Merge tag 'riscv-for-linus-6.18-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull more RISC-V updates from Paul Walmsley:

- Support for the RISC-V-standardized RPMI interface.

RPMI is a platform management communication mechanism between OSes
running on application processors, and a remote platform management
processor. Similar to ARM SCMI, TI SCI, etc. This includes irqchip,
mailbox, and clk changes.

- Support for the RISC-V-standardized MPXY SBI extension.

MPXY is a RISC-V-specific standard implementing a shared memory
mailbox between S-mode operating systems (e.g., Linux) and M-mode
firmware (e.g., OpenSBI). It is part of this PR since one of its use
cases is to enable M-mode firmware to act as a single RPMI client for
all RPMI activity on a core (including S-mode RPMI activity).
Includes a mailbox driver.

- Some ACPI-related updates to enable the use of RPMI and MPXY.

- The addition of Linux-wide memcpy_{from,to}_le32() static inline
functions, for RPMI use.

- An ACPI Kconfig change to enable boot logos on any ACPI-using
architecture (including RISC-V)

- A RISC-V defconfig change to add GPIO keyboard and event device
support, for front panel shutdown or reboot buttons

* tag 'riscv-for-linus-6.18-mw2' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (26 commits)
clk: COMMON_CLK_RPMI should depend on RISCV
ACPI: support BGRT table on RISC-V
MAINTAINERS: Add entry for RISC-V RPMI and MPXY drivers
RISC-V: Enable GPIO keyboard and event device in RV64 defconfig
irqchip/riscv-rpmi-sysmsi: Add ACPI support
mailbox/riscv-sbi-mpxy: Add ACPI support
irqchip/irq-riscv-imsic-early: Export imsic_acpi_get_fwnode()
ACPI: RISC-V: Add RPMI System MSI to GSI mapping
ACPI: RISC-V: Add support to update gsi range
ACPI: RISC-V: Create interrupt controller list in sorted order
ACPI: scan: Update honor list for RPMI System MSI
ACPI: Add support for nargs_prop in acpi_fwnode_get_reference_args()
ACPI: property: Refactor acpi_fwnode_get_reference_args() to support nargs_prop
irqchip: Add driver for the RPMI system MSI service group
dt-bindings: Add RPMI system MSI interrupt controller bindings
dt-bindings: Add RPMI system MSI message proxy bindings
clk: Add clock driver for the RISC-V RPMI clock service group
dt-bindings: clock: Add RPMI clock service controller bindings
dt-bindings: clock: Add RPMI clock service message proxy bindings
mailbox: Add RISC-V SBI message proxy (MPXY) based mailbox driver
...

Documentation/devicetree/bindings/clock/riscv,rpmi-clock.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/riscv,rpmi-clock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V RPMI clock service group based clock controller
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a
+  messaging protocol which is modular and extensible. The supervisor
+  software can send/receive RPMI messages via SBI MPXY extension [2]
+  or some dedicated supervisor-mode RPMI transport.
+
+  The RPMI specification [1] defines clock service group for accessing
+  system clocks managed by a platform microcontroller. The supervisor
+  software can access RPMI clock service group via SBI MPXY channel or
+  some dedicated supervisor-mode RPMI transport.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+  [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
+
+properties:
+  compatible:
+    description:
+      Intended for use by the supervisor software.
+    const: riscv,rpmi-clock
+
+  mboxes:
+    maxItems: 1
+    description:
+      Mailbox channel of the underlying RPMI transport or SBI message proxy channel.
+
+  "#clock-cells":
+    const: 1
+    description:
+      Platform specific CLOCK_ID as defined by the RISC-V Platform Management
+      Interface (RPMI) specification.
+
+required:
+  - compatible
+  - mboxes
+  - "#clock-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    clock-controller {
+        compatible = "riscv,rpmi-clock";
+        mboxes = <&mpxy_mbox 0x1000 0x0>;
+        #clock-cells = <1>;
+    };
+...

Documentation/devicetree/bindings/clock/riscv,rpmi-mpxy-clock.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/riscv,rpmi-mpxy-clock.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V RPMI clock service group based message proxy
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a
+  messaging protocol which is modular and extensible. The supervisor
+  software can send/receive RPMI messages via SBI MPXY extension [2]
+  or some dedicated supervisor-mode RPMI transport.
+
+  The RPMI specification [1] defines clock service group for accessing
+  system clocks managed by a platform microcontroller. The SBI implementation
+  (machine mode firmware or hypervisor) can implement an SBI MPXY channel
+  to allow RPMI clock service group access to the supervisor software.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+  [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
+
+properties:
+  compatible:
+    description:
+      Intended for use by the SBI implementation.
+    const: riscv,rpmi-mpxy-clock
+
+  mboxes:
+    maxItems: 1
+    description:
+      Mailbox channel of the underlying RPMI transport.
+
+  riscv,sbi-mpxy-channel-id:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      The SBI MPXY channel id to be used for providing RPMI access to
+      the supervisor software.
+
+required:
+  - compatible
+  - mboxes
+  - riscv,sbi-mpxy-channel-id
+
+additionalProperties: false
+
+examples:
+  - |
+    clock-service {
+        compatible = "riscv,rpmi-mpxy-clock";
+        mboxes = <&rpmi_shmem_mbox 0x8>;
+        riscv,sbi-mpxy-channel-id = <0x1000>;
+    };
+...

Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-mpxy-system-msi.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/riscv,rpmi-mpxy-system-msi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V RPMI system MSI service group based message proxy
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a
+  messaging protocol which is modular and extensible. The supervisor
+  software can send/receive RPMI messages via SBI MPXY extension [2]
+  or some dedicated supervisor-mode RPMI transport.
+
+  The RPMI specification [1] defines system MSI service group which
+  allow application processors to receive MSIs upon system events
+  such as P2A doorbell, graceful shutdown/reboot request, CPU hotplug
+  event, memory hotplug event, etc from the platform microcontroller.
+  The SBI implementation (machine mode firmware or hypervisor) can
+  implement an SBI MPXY channel to allow RPMI system MSI service
+  group access to the supervisor software.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+  [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
+
+properties:
+  compatible:
+    description:
+      Intended for use by the SBI implementation.
+    const: riscv,rpmi-mpxy-system-msi
+
+  mboxes:
+    maxItems: 1
+    description:
+      Mailbox channel of the underlying RPMI transport.
+
+  riscv,sbi-mpxy-channel-id:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      The SBI MPXY channel id to be used for providing RPMI access to
+      the supervisor software.
+
+required:
+  - compatible
+  - mboxes
+  - riscv,sbi-mpxy-channel-id
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller {
+        compatible = "riscv,rpmi-mpxy-system-msi";
+        mboxes = <&rpmi_shmem_mbox 0x2>;
+        riscv,sbi-mpxy-channel-id = <0x2000>;
+    };
+...

Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/riscv,rpmi-system-msi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V RPMI system MSI service group based interrupt controller
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a
+  messaging protocol which is modular and extensible. The supervisor
+  software can send/receive RPMI messages via SBI MPXY extension [2]
+  or some dedicated supervisor-mode RPMI transport.
+
+  The RPMI specification [1] defines system MSI service group which
+  allow application processors to receive MSIs upon system events
+  such as P2A doorbell, graceful shutdown/reboot request, CPU hotplug
+  event, memory hotplug event, etc from the platform microcontroller.
+  The supervisor software can access RPMI system MSI service group via
+  SBI MPXY channel or some dedicated supervisor-mode RPMI transport.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+  [2] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
+
+allOf:
+  - $ref: /schemas/interrupt-controller.yaml#
+
+properties:
+  compatible:
+    description:
+      Intended for use by the supervisor software.
+    const: riscv,rpmi-system-msi
+
+  mboxes:
+    maxItems: 1
+    description:
+      Mailbox channel of the underlying RPMI transport or SBI message proxy channel.
+
+  msi-parent: true
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 1
+
+required:
+  - compatible
+  - mboxes
+  - msi-parent
+  - interrupt-controller
+  - "#interrupt-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    interrupt-controller {
+        compatible = "riscv,rpmi-system-msi";
+        mboxes = <&mpxy_mbox 0x2000 0x0>;
+        msi-parent = <&imsic_slevel>;
+        interrupt-controller;
+        #interrupt-cells = <1>;
+    };
+...

Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/riscv,rpmi-shmem-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V Platform Management Interface (RPMI) shared memory mailbox
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V Platform Management Interface (RPMI) [1] defines a common shared
+  memory based RPMI transport. This RPMI shared memory transport integrates as
+  mailbox controller in the SBI implementation or supervisor software whereas
+  each RPMI service group is mailbox client in the SBI implementation and
+  supervisor software.
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+properties:
+  compatible:
+    const: riscv,rpmi-shmem-mbox
+
+  reg:
+    minItems: 2
+    items:
+      - description: A2P request queue base address
+      - description: P2A acknowledgment queue base address
+      - description: P2A request queue base address
+      - description: A2P acknowledgment queue base address
+      - description: A2P doorbell address
+
+  reg-names:
+    minItems: 2
+    items:
+      - const: a2p-req
+      - const: p2a-ack
+      - enum: [ p2a-req, a2p-doorbell ]
+      - const: a2p-ack
+      - const: a2p-doorbell
+
+  interrupts:
+    maxItems: 1
+    description:
+      The RPMI shared memory transport supports P2A doorbell as a wired
+      interrupt and this property specifies the interrupt source.
+
+  msi-parent:
+    description:
+      The RPMI shared memory transport supports P2A doorbell as a system MSI
+      and this property specifies the target MSI controller.
+
+  riscv,slot-size:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    minimum: 64
+    description:
+      Power-of-2 RPMI slot size of the RPMI shared memory transport.
+
+  riscv,a2p-doorbell-value:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 0x1
+    description:
+      Value written to the 32-bit A2P doorbell register.
+
+  riscv,p2a-doorbell-sysmsi-index:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      The RPMI shared memory transport supports P2A doorbell as a system MSI
+      and this property specifies system MSI index to be used for configuring
+      the P2A doorbell MSI.
+
+  "#mbox-cells":
+    const: 1
+    description:
+      The first cell specifies RPMI service group ID.
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - riscv,slot-size
+  - "#mbox-cells"
+
+anyOf:
+  - required:
+      - interrupts
+  - required:
+      - msi-parent
+
+additionalProperties: false
+
+examples:
+  - |
+    // Example 1 (RPMI shared memory with only 2 queues):
+    mailbox@10080000 {
+        compatible = "riscv,rpmi-shmem-mbox";
+        reg = <0x10080000 0x10000>,
+              <0x10090000 0x10000>;
+        reg-names = "a2p-req", "p2a-ack";
+        msi-parent = <&imsic_mlevel>;
+        riscv,slot-size = <64>;
+        #mbox-cells = <1>;
+    };
+  - |
+    // Example 2 (RPMI shared memory with only 4 queues):
+    mailbox@10001000 {
+        compatible = "riscv,rpmi-shmem-mbox";
+        reg = <0x10001000 0x800>,
+              <0x10001800 0x800>,
+              <0x10002000 0x800>,
+              <0x10002800 0x800>,
+              <0x10003000 0x4>;
+        reg-names = "a2p-req", "p2a-ack", "p2a-req", "a2p-ack", "a2p-doorbell";
+        msi-parent = <&imsic_mlevel>;
+        riscv,slot-size = <64>;
+        riscv,a2p-doorbell-value = <0x00008000>;
+        #mbox-cells = <1>;
+    };

Documentation/devicetree/bindings/mailbox/riscv,sbi-mpxy-mbox.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/riscv,sbi-mpxy-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RISC-V SBI Message Proxy (MPXY) extension based mailbox
+
+maintainers:
+  - Anup Patel <[e-mail]>
+
+description: |
+  The RISC-V SBI Message Proxy (MPXY) extension [1] allows supervisor
+  software to send messages through the SBI implementation (M-mode
+  firmware or HS-mode hypervisor). The underlying message protocol
+  and message format used by the supervisor software could be some
+  other standard protocol compatible with the SBI MPXY extension
+  (such as RISC-V Platform Management Interface (RPMI) [2]).
+
+  ===========================================
+  References
+  ===========================================
+
+  [1] RISC-V Supervisor Binary Interface (SBI) v3.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-sbi-doc/releases
+
+  [2] RISC-V Platform Management Interface (RPMI) v1.0 (or higher)
+      https://github.com/riscv-non-isa/riscv-rpmi/releases
+
+properties:
+  compatible:
+    const: riscv,sbi-mpxy-mbox
+
+  "#mbox-cells":
+    const: 2
+    description:
+      The first cell specifies channel_id of the SBI MPXY channel,
+      the second cell specifies MSG_PROT_ID of the SBI MPXY channel
+
+required:
+  - compatible
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    mailbox {
+          compatible = "riscv,sbi-mpxy-mbox";
+          #mbox-cells = <2>;
+    };

MAINTAINERS

···
 F:	drivers/perf/riscv_pmu_legacy.c
 F:	drivers/perf/riscv_pmu_sbi.c
 
+RISC-V RPMI AND MPXY DRIVERS
+M:	Rahul Pathak <[e-mail]>
+M:	Anup Patel <[e-mail]>
+L:	[e-mail]
+F:	Documentation/devicetree/bindings/clock/riscv,rpmi-clock.yaml
+F:	Documentation/devicetree/bindings/clock/riscv,rpmi-mpxy-clock.yaml
+F:	Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-mpxy-system-msi.yaml
+F:	Documentation/devicetree/bindings/interrupt-controller/riscv,rpmi-system-msi.yaml
+F:	Documentation/devicetree/bindings/mailbox/riscv,rpmi-shmem-mbox.yaml
+F:	Documentation/devicetree/bindings/mailbox/riscv,sbi-mpxy-mbox.yaml
+F:	drivers/clk/clk-rpmi.c
+F:	drivers/irqchip/irq-riscv-rpmi-sysmsi.c
+F:	drivers/mailbox/riscv-sbi-mpxy-mbox.c
+F:	include/linux/mailbox/riscv-rpmi-message.h
+
 RISC-V SPACEMIT SoC Support
 M:	Yixun Lan <[e-mail]>
 L:	[e-mail]

arch/riscv/configs/defconfig

···
 CONFIG_MICROSEMI_PHY=y
 CONFIG_MOTORCOMM_PHY=y
 CONFIG_INPUT_MOUSEDEV=y
+CONFIG_INPUT_EVDEV=y
+CONFIG_KEYBOARD_GPIO=y
 CONFIG_KEYBOARD_SUN4I_LRADC=m
 CONFIG_SERIAL_8250=y
 CONFIG_SERIAL_8250_CONSOLE=y

arch/riscv/include/asm/irq.h

···
 	ACPI_RISCV_IRQCHIP_IMSIC	= 0x01,
 	ACPI_RISCV_IRQCHIP_PLIC		= 0x02,
 	ACPI_RISCV_IRQCHIP_APLIC	= 0x03,
+	ACPI_RISCV_IRQCHIP_SMSI		= 0x04,
 };
 
 int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
···
 unsigned int acpi_rintc_get_plic_nr_contexts(unsigned int plic_id);
 unsigned int acpi_rintc_get_plic_context(unsigned int plic_id, unsigned int ctxt_idx);
 int __init acpi_rintc_get_imsic_mmio_info(u32 index, struct resource *res);
+int riscv_acpi_update_gsi_range(u32 gsi_base, u32 nr_irqs);
 
 #else
 static inline int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
···
 	return 0;
 }
 
+static inline int riscv_acpi_update_gsi_range(u32 gsi_base, u32 nr_irqs)
+{
+	return -ENODEV;
+}
 #endif /* CONFIG_ACPI */
 
 #endif /* _ASM_RISCV_IRQ_H */

arch/riscv/include/asm/sbi.h

···
 	SBI_EXT_STA = 0x535441,
 	SBI_EXT_NACL = 0x4E41434C,
 	SBI_EXT_FWFT = 0x46574654,
+	SBI_EXT_MPXY = 0x4D505859,
 
 	/* Experimentals extensions must lie within this range */
 	SBI_EXT_EXPERIMENTAL_START = 0x08000000,
···
 #define SBI_FWFT_GLOBAL_FEATURE_BIT		BIT(31)
 
 #define SBI_FWFT_SET_FLAG_LOCK			BIT(0)
+
+enum sbi_ext_mpxy_fid {
+	SBI_EXT_MPXY_GET_SHMEM_SIZE,
+	SBI_EXT_MPXY_SET_SHMEM,
+	SBI_EXT_MPXY_GET_CHANNEL_IDS,
+	SBI_EXT_MPXY_READ_ATTRS,
+	SBI_EXT_MPXY_WRITE_ATTRS,
+	SBI_EXT_MPXY_SEND_MSG_WITH_RESP,
+	SBI_EXT_MPXY_SEND_MSG_WITHOUT_RESP,
+	SBI_EXT_MPXY_GET_NOTIFICATION_EVENTS,
+};
+
+enum sbi_mpxy_attribute_id {
+	/* Standard channel attributes managed by MPXY framework */
+	SBI_MPXY_ATTR_MSG_PROT_ID		= 0x00000000,
+	SBI_MPXY_ATTR_MSG_PROT_VER		= 0x00000001,
+	SBI_MPXY_ATTR_MSG_MAX_LEN		= 0x00000002,
+	SBI_MPXY_ATTR_MSG_SEND_TIMEOUT		= 0x00000003,
+	SBI_MPXY_ATTR_MSG_COMPLETION_TIMEOUT	= 0x00000004,
+	SBI_MPXY_ATTR_CHANNEL_CAPABILITY	= 0x00000005,
+	SBI_MPXY_ATTR_SSE_EVENT_ID		= 0x00000006,
+	SBI_MPXY_ATTR_MSI_CONTROL		= 0x00000007,
+	SBI_MPXY_ATTR_MSI_ADDR_LO		= 0x00000008,
+	SBI_MPXY_ATTR_MSI_ADDR_HI		= 0x00000009,
+	SBI_MPXY_ATTR_MSI_DATA			= 0x0000000A,
+	SBI_MPXY_ATTR_EVENTS_STATE_CONTROL	= 0x0000000B,
+	SBI_MPXY_ATTR_STD_ATTR_MAX_IDX,
+	/*
+	 * Message protocol specific attributes, managed by
+	 * the message protocol specification.
+	 */
+	SBI_MPXY_ATTR_MSGPROTO_ATTR_START	= 0x80000000,
+	SBI_MPXY_ATTR_MSGPROTO_ATTR_END		= 0xffffffff
+};
+
+/* Possible values of MSG_PROT_ID attribute as-per SBI v3.0 (or higher) */
+enum sbi_mpxy_msgproto_id {
+	SBI_MPXY_MSGPROTO_RPMI_ID = 0x0,
+};
+
+/* RPMI message protocol specific MPXY attributes */
+enum sbi_mpxy_rpmi_attribute_id {
+	SBI_MPXY_RPMI_ATTR_SERVICEGROUP_ID = SBI_MPXY_ATTR_MSGPROTO_ATTR_START,
+	SBI_MPXY_RPMI_ATTR_SERVICEGROUP_VERSION,
+	SBI_MPXY_RPMI_ATTR_IMPL_ID,
+	SBI_MPXY_RPMI_ATTR_IMPL_VERSION,
+	SBI_MPXY_RPMI_ATTR_MAX_ID
+};
+
+/* Encoding of MSG_PROT_VER attribute */
+#define SBI_MPXY_MSG_PROT_VER_MAJOR(__ver)	upper_16_bits(__ver)
+#define SBI_MPXY_MSG_PROT_VER_MINOR(__ver)	lower_16_bits(__ver)
+#define SBI_MPXY_MSG_PROT_MKVER(__maj, __min)	(((u32)(__maj) << 16) | (u16)(__min))
+
+/* Capabilities available through CHANNEL_CAPABILITY attribute */
+#define SBI_MPXY_CHAN_CAP_MSI			BIT(0)
+#define SBI_MPXY_CHAN_CAP_SSE			BIT(1)
+#define SBI_MPXY_CHAN_CAP_EVENTS_STATE		BIT(2)
+#define SBI_MPXY_CHAN_CAP_SEND_WITH_RESP	BIT(3)
+#define SBI_MPXY_CHAN_CAP_SEND_WITHOUT_RESP	BIT(4)
+#define SBI_MPXY_CHAN_CAP_GET_NOTIFICATIONS	BIT(5)
 
 /* SBI spec version fields */
 #define SBI_SPEC_VERSION_DEFAULT	0x1

drivers/acpi/Kconfig

···
 
 config ACPI_BGRT
 	bool "Boottime Graphics Resource Table support"
-	depends on EFI && (X86 || ARM64 || LOONGARCH)
+	depends on EFI
 	help
 	  This driver adds support for exposing the ACPI Boottime Graphics
 	  Resource Table, which allows the operating system to obtain

drivers/acpi/property.c

···
 	return NULL;
 }
 
+static unsigned int acpi_fwnode_get_args_count(struct fwnode_handle *fwnode,
+					       const char *nargs_prop)
+{
+	const struct acpi_device_data *data;
+	const union acpi_object *obj;
+	int ret;
+
+	data = acpi_device_data_of_node(fwnode);
+	if (!data)
+		return 0;
+
+	ret = acpi_data_get_property(data, nargs_prop, ACPI_TYPE_INTEGER, &obj);
+	if (ret)
+		return 0;
+
+	return obj->integer.value;
+}
+
 static int acpi_get_ref_args(struct fwnode_reference_args *args,
 			     struct fwnode_handle *ref_fwnode,
+			     const char *nargs_prop,
 			     const union acpi_object **element,
 			     const union acpi_object *end, size_t num_args)
 {
 	u32 nargs = 0, i;
+
+	if (nargs_prop)
+		num_args = acpi_fwnode_get_args_count(ref_fwnode, nargs_prop);
 
 	/*
 	 * Assume the following integer elements are all args. Stop counting on
···
 	return &dn->fwnode;
 }
 
-/**
- * __acpi_node_get_property_reference - returns handle to the referenced object
- * @fwnode: Firmware node to get the property from
- * @propname: Name of the property
- * @index: Index of the reference to return
- * @num_args: Maximum number of arguments after each reference
- * @args: Location to store the returned reference with optional arguments
- *	  (may be NULL)
- *
- * Find property with @name, verifify that it is a package containing at least
- * one object reference and if so, store the ACPI device object pointer to the
- * target object in @args->adev.  If the reference includes arguments, store
- * them in the @args->args[] array.
- *
- * If there's more than one reference in the property value package, @index is
- * used to select the one to return.
- *
- * It is possible to leave holes in the property value set like in the
- * example below:
- *
- * Package () {
- *     "cs-gpios",
- *     Package () {
- *        ^GPIO, 19, 0, 0,
- *        ^GPIO, 20, 0, 0,
- *        0,
- *        ^GPIO, 21, 0, 0,
- *     }
- * }
- *
- * Calling this function with index %2 or index %3 return %-ENOENT. If the
- * property does not contain any more values %-ENOENT is returned. The NULL
- * entry must be single integer and preferably contain value %0.
- *
- * Return: %0 on success, negative error code on failure.
- */
-int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
-	const char *propname, size_t index, size_t num_args,
-	struct fwnode_reference_args *args)
+static int acpi_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
+					  const char *propname, const char *nargs_prop,
+					  unsigned int args_count, unsigned int index,
+					  struct fwnode_reference_args *args)
 {
 	const union acpi_object *element, *end;
 	const union acpi_object *obj;
···
 				return -EINVAL;
 
 			element++;
-
 			ret = acpi_get_ref_args(idx == index ? args : NULL,
 						acpi_fwnode_handle(device),
-						&element, end, num_args);
+						nargs_prop, &element, end,
+						args_count);
 			if (ret < 0)
 				return ret;
 
···
 				return -EINVAL;
 
 			element++;
-
 			ret = acpi_get_ref_args(idx == index ? args : NULL,
-						ref_fwnode, &element, end,
-						num_args);
+						ref_fwnode, nargs_prop, &element, end,
+						args_count);
 			if (ret < 0)
 				return ret;
 
···
 	}
 
 	return -ENOENT;
+}
+
+/**
+ * __acpi_node_get_property_reference - returns handle to the referenced object
+ * @fwnode: Firmware node to get the property from
+ * @propname: Name of the property
+ * @index: Index of the reference to return
+ * @num_args: Maximum number of arguments after each reference
+ * @args: Location to store the returned reference with optional arguments
+ *	  (may be NULL)
+ *
+ * Find property with @name, verifify that it is a package containing at least
+ * one object reference and if so, store the ACPI device object pointer to the
+ * target object in @args->adev.  If the reference includes arguments, store
+ * them in the @args->args[] array.
+ *
+ * If there's more than one reference in the property value package, @index is
+ * used to select the one to return.
+ *
+ * It is possible to leave holes in the property value set like in the
+ * example below:
+ *
+ * Package () {
+ *     "cs-gpios",
+ *     Package () {
+ *        ^GPIO, 19, 0, 0,
+ *        ^GPIO, 20, 0, 0,
+ *        0,
+ *        ^GPIO, 21, 0, 0,
+ *     }
+ * }
+ *
+ * Calling this function with index %2 or index %3 return %-ENOENT. If the
+ * property does not contain any more values %-ENOENT is returned. The NULL
+ * entry must be single integer and preferably contain value %0.
+ *
+ * Return: %0 on success, negative error code on failure.
+ */
+int __acpi_node_get_property_reference(const struct fwnode_handle *fwnode,
+				       const char *propname, size_t index,
+				       size_t num_args,
+				       struct fwnode_reference_args *args)
+{
+	return acpi_fwnode_get_reference_args(fwnode, propname, NULL, index, num_args, args);
 }
 EXPORT_SYMBOL_GPL(__acpi_node_get_property_reference);
 
···
 {
 	return acpi_node_prop_read(fwnode, propname, DEV_PROP_STRING,
 				   val, nval);
-}
-
-static int
-acpi_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
-			       const char *prop, const char *nargs_prop,
-			       unsigned int args_count, unsigned int index,
-			       struct fwnode_reference_args *args)
-{
-	return __acpi_node_get_property_reference(fwnode, prop, index,
-						  args_count, args);
 }
 
 static const char *acpi_fwnode_get_name(const struct fwnode_handle *fwnode)

drivers/acpi/riscv/irq.c

···
 
 #include "init.h"
 
+#define RISCV_ACPI_INTC_FLAG_PENDING BIT(0)
+
 struct riscv_ext_intc_list {
 	acpi_handle		handle;
 	u32			gsi_base;
···
 	u32			nr_idcs;
 	u32			id;
 	u32			type;
+	u32			flag;
 	struct list_head	list;
 };
 
···
 	return AE_NOT_FOUND;
 }
 
+int riscv_acpi_update_gsi_range(u32 gsi_base, u32 nr_irqs)
+{
+	struct riscv_ext_intc_list *ext_intc_element;
+
+	list_for_each_entry(ext_intc_element, &ext_intc_list, list) {
+		if (gsi_base == ext_intc_element->gsi_base &&
+		    (ext_intc_element->flag & RISCV_ACPI_INTC_FLAG_PENDING)) {
+			ext_intc_element->nr_irqs = nr_irqs;
+			ext_intc_element->flag &= ~RISCV_ACPI_INTC_FLAG_PENDING;
+			return 0;
+		}
+	}
+
+	return -ENODEV;
+}
+
 int riscv_acpi_get_gsi_info(struct fwnode_handle *fwnode, u32 *gsi_base,
 			    u32 *id, u32 *nr_irqs, u32 *nr_idcs)
 {
···
 static int __init riscv_acpi_register_ext_intc(u32 gsi_base, u32 nr_irqs, u32 nr_idcs,
 					       u32 id, u32 type)
 {
-	struct riscv_ext_intc_list *ext_intc_element;
+	struct riscv_ext_intc_list *ext_intc_element, *node, *prev;
 
 	ext_intc_element = kzalloc(sizeof(*ext_intc_element), GFP_KERNEL);
 	if (!ext_intc_element)
 		return -ENOMEM;
 
 	ext_intc_element->gsi_base = gsi_base;
-	ext_intc_element->nr_irqs = nr_irqs;
+
+	/* If nr_irqs is zero, indicate it in flag and set to max range possible */
+	if (nr_irqs) {
+		ext_intc_element->nr_irqs = nr_irqs;
+	} else {
+		ext_intc_element->flag |= RISCV_ACPI_INTC_FLAG_PENDING;
+		ext_intc_element->nr_irqs = U32_MAX - ext_intc_element->gsi_base;
+	}
+
 	ext_intc_element->nr_idcs = nr_idcs;
 	ext_intc_element->id = id;
-	list_add_tail(&ext_intc_element->list, &ext_intc_list);
+	list_for_each_entry(node, &ext_intc_list, list) {
+		if (node->gsi_base < ext_intc_element->gsi_base)
+			break;
+	}
+
+	/* Adjust the previous node's GSI range if that has pending registration */
+	prev = list_prev_entry(node, list);
+	if (!list_entry_is_head(prev, &ext_intc_list, list)) {
+		if (prev->flag & RISCV_ACPI_INTC_FLAG_PENDING)
+			prev->nr_irqs = ext_intc_element->gsi_base - prev->gsi_base;
+	}
+
+	list_add_tail(&ext_intc_element->list, &node->list);
 	return 0;
+}
+
+static acpi_status __init riscv_acpi_create_gsi_map_smsi(acpi_handle handle, u32 level,
+							 void *context, void **return_value)
+{
+	acpi_status status;
+	u64 gbase;
+
+	if (!acpi_has_method(handle, "_GSB")) {
+		acpi_handle_err(handle, "_GSB method not found\n");
+		return AE_ERROR;
+	}
+
+	status = acpi_evaluate_integer(handle, "_GSB", NULL, &gbase);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to evaluate _GSB method\n");
+		return status;
+	}
+
+	riscv_acpi_register_ext_intc(gbase, 0, 0, 0, ACPI_RISCV_IRQCHIP_SMSI);
+	status = riscv_acpi_update_gsi_handle((u32)gbase, handle);
+	if (ACPI_FAILURE(status)) {
+		acpi_handle_err(handle, "failed to find the GSI mapping entry\n");
+		return status;
+	}
+
+	return AE_OK;
 }
 
 static acpi_status __init riscv_acpi_create_gsi_map(acpi_handle handle, u32 level,
···
 
 	if (acpi_table_parse_madt(ACPI_MADT_TYPE_APLIC, riscv_acpi_aplic_parse_madt, 0) > 0)
 		acpi_get_devices("RSCV0002", riscv_acpi_create_gsi_map, NULL, NULL);
+
+	/* Unlike PLIC/APLIC, SYSMSI doesn't have MADT */
+	acpi_get_devices("RSCV0006", riscv_acpi_create_gsi_map_smsi, NULL, NULL);
 }
 
 static acpi_handle riscv_acpi_get_gsi_handle(u32 gsi)

drivers/acpi/scan.c

···
 	"INTC10CF", /* IVSC (MTL) driver must be loaded to allow i2c access to camera sensors */
 	"RSCV0001", /* RISC-V PLIC */
 	"RSCV0002", /* RISC-V APLIC */
+	"RSCV0005", /* RISC-V SBI MPXY MBOX */
+	"RSCV0006", /* RISC-V RPMI SYSMSI */
 	"PNP0C0F",  /* PCI Link Device */
 	NULL
 };

drivers/base/property.c

···
  * @prop:	The name of the property
  * @nargs_prop:	The name of the property telling the number of
  *		arguments in the referred node. NULL if @nargs is known,
- *		otherwise @nargs is ignored. Only relevant on OF.
+ *		otherwise @nargs is ignored.
  * @nargs:	Number of arguments. Ignored if @nargs_prop is non-NULL.
  * @index:	Index of the reference, from zero onwards.
  * @args:	Result structure with reference and integer arguments.

drivers/clk/Kconfig

···
 	  Not all features of the PLL are currently supported
 	  by the driver.
 
+config COMMON_CLK_RPMI
+	tristate "Clock driver based on RISC-V RPMI"
+	depends on RISCV || COMPILE_TEST
+	depends on MAILBOX
+	default RISCV
+	help
+	  Support for clocks based on the clock service group defined by
+	  the RISC-V platform management interface (RPMI) specification.
+
 source "drivers/clk/actions/Kconfig"
 source "drivers/clk/analogbits/Kconfig"
 source "drivers/clk/baikal-t1/Kconfig"

drivers/clk/Makefile

···
 obj-$(CONFIG_CLK_QORIQ)			+= clk-qoriq.o
 obj-$(CONFIG_COMMON_CLK_RK808)		+= clk-rk808.o
 obj-$(CONFIG_COMMON_CLK_RP1)            += clk-rp1.o
+obj-$(CONFIG_COMMON_CLK_RPMI)		+= clk-rpmi.o
 obj-$(CONFIG_COMMON_CLK_HI655X)		+= clk-hi655x.o
 obj-$(CONFIG_COMMON_CLK_S2MPS11)	+= clk-s2mps11.o
 obj-$(CONFIG_COMMON_CLK_SCMI)           += clk-scmi.o

drivers/clk/clk-rpmi.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V MPXY Based Clock Driver
+ *
+ * Copyright (C) 2025 Ventana Micro Systems Ltd.
+ */
+
+#include <linux/clk-provider.h>
+#include <linux/err.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox/riscv-rpmi-message.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/wordpart.h>
+
+#define RPMI_CLK_DISCRETE_MAX_NUM_RATES		16
+#define RPMI_CLK_NAME_LEN			16
+
+#define to_rpmi_clk(clk)	container_of(clk, struct rpmi_clk, hw)
+
+enum rpmi_clk_config {
+	RPMI_CLK_DISABLE = 0,
+	RPMI_CLK_ENABLE = 1,
+	RPMI_CLK_CONFIG_MAX_IDX
+};
+
+#define RPMI_CLK_TYPE_MASK			GENMASK(1, 0)
+enum rpmi_clk_type {
+	RPMI_CLK_DISCRETE = 0,
+	RPMI_CLK_LINEAR = 1,
+	RPMI_CLK_TYPE_MAX_IDX
+};
+
+struct rpmi_clk_context {
+	struct device *dev;
+	struct mbox_chan *chan;
+	struct mbox_client client;
+	u32 max_msg_data_size;
+};
+
+/*
+ * rpmi_clk_rates represents the rates format
+ * as specified by the RPMI specification.
+ * No other data format (e.g., struct linear_range)
+ * is required to avoid to and from conversion.
+ */
+union rpmi_clk_rates {
+	u64 discrete[RPMI_CLK_DISCRETE_MAX_NUM_RATES];
+	struct {
+		u64 min;
+		u64 max;
+		u64 step;
+	} linear;
+};
+
+struct rpmi_clk {
+	struct rpmi_clk_context *context;
+	u32 id;
+	u32 num_rates;
+	u32 transition_latency;
+	enum rpmi_clk_type type;
+	union rpmi_clk_rates *rates;
+	char name[RPMI_CLK_NAME_LEN];
+	struct clk_hw hw;
+};
+
+struct rpmi_clk_rate_discrete {
+	__le32 lo;
+	__le32 hi;
+};
+
+struct rpmi_clk_rate_linear {
+	__le32 min_lo;
+	__le32 min_hi;
+	__le32 max_lo;
+	__le32 max_hi;
+	__le32 step_lo;
+	__le32 step_hi;
+};
+
+struct rpmi_get_num_clocks_rx {
+	__le32 status;
+	__le32 num_clocks;
+};
+
+struct rpmi_get_attrs_tx {
+	__le32 clkid;
+};
+
+struct rpmi_get_attrs_rx {
+	__le32 status;
+	__le32 flags;
+	__le32 num_rates;
+	__le32 transition_latency;
+	char name[RPMI_CLK_NAME_LEN];
+};
+
+struct rpmi_get_supp_rates_tx {
+	__le32 clkid;
+	__le32 clk_rate_idx;
+};
+
+struct rpmi_get_supp_rates_rx {
+	__le32 status;
+	__le32 flags;
+	__le32 remaining;
+	__le32 returned;
+	__le32 rates[];
+};
+
+struct rpmi_get_rate_tx {
+	__le32 clkid;
+};
+
+struct rpmi_get_rate_rx {
+	__le32 status;
+	__le32 lo;
+	__le32 hi;
+};
+
+struct rpmi_set_rate_tx {
+	__le32 clkid;
+	__le32 flags;
+	__le32 lo;
+	__le32 hi;
+};
+
+struct rpmi_set_rate_rx {
+	__le32 status;
+};
+
+struct rpmi_set_config_tx {
+	__le32 clkid;
+	__le32 config;
+};
+
+struct rpmi_set_config_rx {
+	__le32 status;
+};
+
+static inline u64 rpmi_clkrate_u64(u32 __hi, u32 __lo)
+{
+	return (((u64)(__hi) << 32) | (u32)(__lo));
+}
+
+static u32 rpmi_clk_get_num_clocks(struct rpmi_clk_context *context)
+{
+	struct rpmi_get_num_clocks_rx rx, *resp;
+	struct rpmi_mbox_message msg;
+	int ret;
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_NUM_CLOCKS,
+					  NULL, 0, &rx, sizeof(rx));
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return 0;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp || resp->status)
+		return 0;
+
+	return le32_to_cpu(resp->num_clocks);
+}
+
+static int rpmi_clk_get_attrs(u32 clkid, struct rpmi_clk *rpmi_clk)
+{
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_mbox_message msg;
+	struct rpmi_get_attrs_tx tx;
+	struct rpmi_get_attrs_rx rx, *resp;
+	u8 format;
+	int ret;
+
+	tx.clkid = cpu_to_le32(clkid);
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_ATTRIBUTES,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return ret;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp)
+		return -EINVAL;
+	if (resp->status)
+		return rpmi_to_linux_error(le32_to_cpu(resp->status));
+
+	rpmi_clk->id = clkid;
+	rpmi_clk->num_rates = le32_to_cpu(resp->num_rates);
+	rpmi_clk->transition_latency = le32_to_cpu(resp->transition_latency);
+	strscpy(rpmi_clk->name, resp->name, RPMI_CLK_NAME_LEN);
+
+	format = le32_to_cpu(resp->flags) & RPMI_CLK_TYPE_MASK;
+	if (format >= RPMI_CLK_TYPE_MAX_IDX)
+		return -EINVAL;
+
+	rpmi_clk->type = format;
+
+	return 0;
+}
+
+static int rpmi_clk_get_supported_rates(u32 clkid, struct rpmi_clk *rpmi_clk)
+{
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_clk_rate_discrete *rate_discrete;
+	struct rpmi_clk_rate_linear *rate_linear;
+	struct rpmi_get_supp_rates_tx tx;
+	struct rpmi_get_supp_rates_rx *resp;
+	struct rpmi_mbox_message msg;
+	size_t clk_rate_idx;
+	int ret, rateidx, j;
+
+	tx.clkid = cpu_to_le32(clkid);
+	tx.clk_rate_idx = 0;
+
+	/*
+	 * Make sure we allocate rx buffer sufficient to be accommodate all
+	 * the rates sent in one RPMI message.
+	 */
+	struct rpmi_get_supp_rates_rx *rx __free(kfree) =
+					kzalloc(context->max_msg_data_size, GFP_KERNEL);
+	if (!rx)
+		return -ENOMEM;
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_SUPPORTED_RATES,
+					  &tx, sizeof(tx), rx, context->max_msg_data_size);
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return ret;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp)
+		return -EINVAL;
+	if (resp->status)
+		return rpmi_to_linux_error(le32_to_cpu(resp->status));
+	if (!le32_to_cpu(resp->returned))
+		return -EINVAL;
+
+	if (rpmi_clk->type == RPMI_CLK_DISCRETE) {
+		rate_discrete = (struct rpmi_clk_rate_discrete *)resp->rates;
+
+		for (rateidx = 0; rateidx < le32_to_cpu(resp->returned); rateidx++) {
+			rpmi_clk->rates->discrete[rateidx] =
+				rpmi_clkrate_u64(le32_to_cpu(rate_discrete[rateidx].hi),
+						 le32_to_cpu(rate_discrete[rateidx].lo));
+		}
+
+		/*
+		 * Keep sending the request message until all
+		 * the rates are received.
+		 */
+		clk_rate_idx = 0;
+		while (le32_to_cpu(resp->remaining)) {
+			clk_rate_idx += le32_to_cpu(resp->returned);
+			tx.clk_rate_idx = cpu_to_le32(clk_rate_idx);
+
+			rpmi_mbox_init_send_with_response(&msg,
+							  RPMI_CLK_SRV_GET_SUPPORTED_RATES,
+							  &tx, sizeof(tx),
+							  rx, context->max_msg_data_size);
+
+			ret = rpmi_mbox_send_message(context->chan, &msg);
+			if (ret)
+				return ret;
+
+			resp = rpmi_mbox_get_msg_response(&msg);
+			if (!resp)
+				return -EINVAL;
+			if (resp->status)
+				return rpmi_to_linux_error(le32_to_cpu(resp->status));
+			if (!le32_to_cpu(resp->returned))
+				return -EINVAL;
+
+			for (j = 0; j < le32_to_cpu(resp->returned); j++) {
+				if (rateidx >= clk_rate_idx + le32_to_cpu(resp->returned))
+					break;
+				rpmi_clk->rates->discrete[rateidx++] =
+					rpmi_clkrate_u64(le32_to_cpu(rate_discrete[j].hi),
+							 le32_to_cpu(rate_discrete[j].lo));
+			}
+		}
+	} else if (rpmi_clk->type == RPMI_CLK_LINEAR) {
+		rate_linear = (struct rpmi_clk_rate_linear *)resp->rates;
+
+		rpmi_clk->rates->linear.min = rpmi_clkrate_u64(le32_to_cpu(rate_linear->min_hi),
+							       le32_to_cpu(rate_linear->min_lo));
+		rpmi_clk->rates->linear.max = rpmi_clkrate_u64(le32_to_cpu(rate_linear->max_hi),
+							       le32_to_cpu(rate_linear->max_lo));
+		rpmi_clk->rates->linear.step = rpmi_clkrate_u64(le32_to_cpu(rate_linear->step_hi),
+								le32_to_cpu(rate_linear->step_lo));
+	}
+
+	return 0;
+}
+
+static unsigned long rpmi_clk_recalc_rate(struct clk_hw *hw,
+					  unsigned long parent_rate)
+{
+	struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_mbox_message msg;
+	struct rpmi_get_rate_tx tx;
+	struct rpmi_get_rate_rx rx, *resp;
+	int ret;
+
+	tx.clkid = cpu_to_le32(rpmi_clk->id);
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_GET_RATE,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return ret;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp)
+		return -EINVAL;
+	if (resp->status)
+		return rpmi_to_linux_error(le32_to_cpu(resp->status));
+
+	return rpmi_clkrate_u64(le32_to_cpu(resp->hi), le32_to_cpu(resp->lo));
+}
+
+static int rpmi_clk_determine_rate(struct clk_hw *hw,
+				   struct clk_rate_request *req)
+{
+	struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
+	u64 fmin, fmax, ftmp;
+
+	/*
+	 * Keep the requested rate if the clock format
+	 * is of discrete type. Let the platform which
+	 * is actually controlling the clock handle that.
+	 */
+	if (rpmi_clk->type == RPMI_CLK_DISCRETE)
+		return 0;
+
+	fmin = rpmi_clk->rates->linear.min;
+	fmax = rpmi_clk->rates->linear.max;
+
+	if (req->rate <= fmin) {
+		req->rate = fmin;
+		return 0;
+	} else if (req->rate >= fmax) {
+		req->rate = fmax;
+		return 0;
+	}
+
+	ftmp = req->rate - fmin;
+	ftmp += rpmi_clk->rates->linear.step - 1;
+	do_div(ftmp, rpmi_clk->rates->linear.step);
+
+	req->rate = ftmp * rpmi_clk->rates->linear.step + fmin;
+
+	return 0;
+}
+
+static int rpmi_clk_set_rate(struct clk_hw *hw, unsigned long rate,
+			     unsigned long parent_rate)
+{
+	struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_mbox_message msg;
+	struct rpmi_set_rate_tx tx;
+	struct rpmi_set_rate_rx rx, *resp;
+	int ret;
+
+	tx.clkid = cpu_to_le32(rpmi_clk->id);
+	tx.lo = cpu_to_le32(lower_32_bits(rate));
+	tx.hi = cpu_to_le32(upper_32_bits(rate));
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_RATE,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return ret;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp)
+		return -EINVAL;
+	if (resp->status)
+		return rpmi_to_linux_error(le32_to_cpu(resp->status));
+
+	return 0;
+}
+
+static int rpmi_clk_enable(struct clk_hw *hw)
+{
+	struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_mbox_message msg;
+	struct rpmi_set_config_tx tx;
+	struct rpmi_set_config_rx rx, *resp;
+	int ret;
+
+	tx.config = cpu_to_le32(RPMI_CLK_ENABLE);
+	tx.clkid = cpu_to_le32(rpmi_clk->id);
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_CONFIG,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return ret;
+
+	resp = rpmi_mbox_get_msg_response(&msg);
+	if (!resp)
+		return -EINVAL;
+	if (resp->status)
+		return rpmi_to_linux_error(le32_to_cpu(resp->status));
+
+	return 0;
+}
+
+static void rpmi_clk_disable(struct clk_hw *hw)
+{
+	struct rpmi_clk *rpmi_clk = to_rpmi_clk(hw);
+	struct rpmi_clk_context *context = rpmi_clk->context;
+	struct rpmi_mbox_message msg;
+	struct rpmi_set_config_tx tx;
+	struct rpmi_set_config_rx rx;
+
+	tx.config = cpu_to_le32(RPMI_CLK_DISABLE);
+	tx.clkid = cpu_to_le32(rpmi_clk->id);
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_CLK_SRV_SET_CONFIG,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+
+	rpmi_mbox_send_message(context->chan, &msg);
+}
+
+static const struct clk_ops rpmi_clk_ops = {
+	.recalc_rate = rpmi_clk_recalc_rate,
+	.determine_rate = rpmi_clk_determine_rate,
+	.set_rate = rpmi_clk_set_rate,
+	.prepare = rpmi_clk_enable,
+	.unprepare = rpmi_clk_disable,
+};
+
+static struct clk_hw *rpmi_clk_enumerate(struct rpmi_clk_context *context, u32 clkid)
+{
+	struct device *dev = context->dev;
+	unsigned long min_rate, max_rate;
+	union rpmi_clk_rates *rates;
+	struct rpmi_clk *rpmi_clk;
+	struct clk_init_data init = {};
+	struct clk_hw *clk_hw;
+	int ret;
+
+	rates = devm_kzalloc(dev, sizeof(*rates), GFP_KERNEL);
+	if (!rates)
+		return ERR_PTR(-ENOMEM);
+
+	rpmi_clk = devm_kzalloc(dev, sizeof(*rpmi_clk), GFP_KERNEL);
+	if (!rpmi_clk)
+		return ERR_PTR(-ENOMEM);
+
+	rpmi_clk->context = context;
+	rpmi_clk->rates = rates;
+
+	ret = rpmi_clk_get_attrs(clkid, rpmi_clk);
+	if (ret)
+		return dev_err_ptr_probe(dev, ret,
+					 "Failed to get clk-%u attributes\n",
+					 clkid);
+
+	ret = rpmi_clk_get_supported_rates(clkid, rpmi_clk);
+	if (ret)
+		return dev_err_ptr_probe(dev, ret,
+					 "Get supported rates failed for clk-%u\n",
+					 clkid);
+
+	init.flags = CLK_GET_RATE_NOCACHE;
+	init.num_parents = 0;
+	init.ops = &rpmi_clk_ops;
+	init.name = rpmi_clk->name;
+	clk_hw = &rpmi_clk->hw;
+	clk_hw->init = &init;
+
+	ret = devm_clk_hw_register(dev, clk_hw);
+	if (ret)
+		return dev_err_ptr_probe(dev, ret,
+					 "Unable to register clk-%u\n",
+					 clkid);
+
+	if (rpmi_clk->type == RPMI_CLK_DISCRETE) {
+		min_rate = rpmi_clk->rates->discrete[0];
+		max_rate = rpmi_clk->rates->discrete[rpmi_clk->num_rates -  1];
+	} else {
+		min_rate = rpmi_clk->rates->linear.min;
+		max_rate = rpmi_clk->rates->linear.max;
+	}
+
+	clk_hw_set_rate_range(clk_hw, min_rate, max_rate);
+
+	return clk_hw;
+}
+
+static void rpmi_clk_mbox_chan_release(void *data)
+{
+	struct mbox_chan *chan = data;
+
+	mbox_free_channel(chan);
+}
+
+static int rpmi_clk_probe(struct platform_device *pdev)
+{
+	int ret;
+	unsigned int num_clocks, i;
+	struct clk_hw_onecell_data *clk_data;
+	struct rpmi_clk_context *context;
+	struct rpmi_mbox_message msg;
+	struct clk_hw *hw_ptr;
+	struct device *dev = &pdev->dev;
+
+	context = devm_kzalloc(dev, sizeof(*context), GFP_KERNEL);
+	if (!context)
+		return -ENOMEM;
+	context->dev = dev;
+	platform_set_drvdata(pdev, context);
+
+	context->client.dev		= context->dev;
+	context->client.rx_callback	= NULL;
+	context->client.tx_block	= false;
+	context->client.knows_txdone	= true;
+	context->client.tx_tout		= 0;
+
+	context->chan = mbox_request_channel(&context->client, 0);
+	if (IS_ERR(context->chan))
+		return PTR_ERR(context->chan);
+
+	ret = devm_add_action_or_reset(dev, rpmi_clk_mbox_chan_release, context->chan);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to add rpmi mbox channel cleanup\n");
+
+	rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SPEC_VERSION);
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get spec version\n");
+	if (msg.attr.value < RPMI_MKVER(1, 0)) {
+		return dev_err_probe(dev, -EINVAL,
+				     "msg protocol version mismatch, expected 0x%x, found 0x%x\n",
+				     RPMI_MKVER(1, 0), msg.attr.value);
+	}
+
+	rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SERVICEGROUP_ID);
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get service group ID\n");
+	if (msg.attr.value != RPMI_SRVGRP_CLOCK) {
+		return dev_err_probe(dev, -EINVAL,
+				     "service group match failed, expected 0x%x, found 0x%x\n",
+				     RPMI_SRVGRP_CLOCK, msg.attr.value);
+	}
+
+	rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_SERVICEGROUP_VERSION);
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get service group version\n");
+	if (msg.attr.value < RPMI_MKVER(1, 0)) {
+		return dev_err_probe(dev, -EINVAL,
+				     "service group version failed, expected 0x%x, found 0x%x\n",
+				     RPMI_MKVER(1, 0), msg.attr.value);
+	}
+
+	rpmi_mbox_init_get_attribute(&msg, RPMI_MBOX_ATTR_MAX_MSG_DATA_SIZE);
+	ret = rpmi_mbox_send_message(context->chan, &msg);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to get max message data size\n");
+
+	context->max_msg_data_size = msg.attr.value;
+	num_clocks = rpmi_clk_get_num_clocks(context);
+	if (!num_clocks)
+		return dev_err_probe(dev, -ENODEV, "No clocks found\n");
+
+	clk_data = devm_kzalloc(dev, struct_size(clk_data, hws, num_clocks),
+				GFP_KERNEL);
+	if (!clk_data)
+		return dev_err_probe(dev, -ENOMEM, "No memory for clock data\n");
+	clk_data->num = num_clocks;
+
+	for (i = 0; i < clk_data->num; i++) {
+		hw_ptr = rpmi_clk_enumerate(context, i);
+		if (IS_ERR(hw_ptr)) {
+			return dev_err_probe(dev, PTR_ERR(hw_ptr),
+					     "Failed to register clk-%d\n", i);
+		}
+		clk_data->hws[i] = hw_ptr;
+	}
+
+	ret = devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get, clk_data);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register clock HW provider\n");
+
+	return 0;
+}
+
+static const struct of_device_id rpmi_clk_of_match[] = {
+	{ .compatible = "riscv,rpmi-clock" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rpmi_clk_of_match);
+
+static struct platform_driver rpmi_clk_driver = {
+	.driver = {
+		.name = "riscv-rpmi-clock",
+		.of_match_table = rpmi_clk_of_match,
+	},
+	.probe = rpmi_clk_probe,
+};
+module_platform_driver(rpmi_clk_driver);
+
+MODULE_AUTHOR("Rahul Pathak <[e-mail]>");
+MODULE_DESCRIPTION("Clock Driver based on RPMI message protocol");
+MODULE_LICENSE("GPL");

drivers/irqchip/Kconfig

···
 	select GENERIC_MSI_IRQ
 	select IRQ_MSI_LIB
 
+config RISCV_RPMI_SYSMSI
+	bool
+	depends on RISCV && MAILBOX
+	select IRQ_DOMAIN_HIERARCHY
+	select GENERIC_MSI_IRQ
+	default RISCV
+
 config SIFIVE_PLIC
 	bool
 	depends on RISCV

drivers/irqchip/Makefile

···
 obj-$(CONFIG_RISCV_APLIC)		+= irq-riscv-aplic-main.o irq-riscv-aplic-direct.o
 obj-$(CONFIG_RISCV_APLIC_MSI)		+= irq-riscv-aplic-msi.o
 obj-$(CONFIG_RISCV_IMSIC)		+= irq-riscv-imsic-state.o irq-riscv-imsic-early.o irq-riscv-imsic-platform.o
+obj-$(CONFIG_RISCV_RPMI_SYSMSI)		+= irq-riscv-rpmi-sysmsi.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_STARFIVE_JH8100_INTC)	+= irq-starfive-jh8100-intc.o
 obj-$(CONFIG_ACLINT_SSWI)		+= irq-aclint-sswi.o

drivers/irqchip/irq-riscv-imsic-early.c

···
 #define pr_fmt(fmt) "riscv-imsic: " fmt
 #include <linux/acpi.h>
 #include <linux/cpu.h>
+#include <linux/export.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
 #include <linux/io.h>
···
 {
 	return imsic_acpi_fwnode;
 }
+EXPORT_SYMBOL_GPL(imsic_acpi_get_fwnode);
 
 static int __init imsic_early_acpi_init(union acpi_subtable_headers *header,
 					const unsigned long end)

drivers/irqchip/irq-riscv-rpmi-sysmsi.c

···
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2025 Ventana Micro Systems Inc. */
+
+#include <linux/acpi.h>
+#include <linux/bits.h>
+#include <linux/bug.h>
+#include <linux/device.h>
+#include <linux/device/devres.h>
+#include <linux/dev_printk.h>
+#include <linux/errno.h>
+#include <linux/irq.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/riscv-imsic.h>
+#include <linux/mailbox_client.h>
+#include <linux/mailbox/riscv-rpmi-message.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+
+struct rpmi_sysmsi_get_attrs_rx {
+	__le32 status;
+	__le32 sys_num_msi;
+	__le32 flag0;
+	__le32 flag1;
+};
+
+#define RPMI_SYSMSI_MSI_ATTRIBUTES_FLAG0_PREF_PRIV	BIT(0)
+
+struct rpmi_sysmsi_set_msi_state_tx {
+	__le32 sys_msi_index;
+	__le32 sys_msi_state;
+};
+
+struct rpmi_sysmsi_set_msi_state_rx {
+	__le32 status;
+};
+
+#define RPMI_SYSMSI_MSI_STATE_ENABLE			BIT(0)
+#define RPMI_SYSMSI_MSI_STATE_PENDING			BIT(1)
+
+struct rpmi_sysmsi_set_msi_target_tx {
+	__le32 sys_msi_index;
+	__le32 sys_msi_address_low;
+	__le32 sys_msi_address_high;
+	__le32 sys_msi_data;
+};
+
+struct rpmi_sysmsi_set_msi_target_rx {
+	__le32 status;
+};
+
+struct rpmi_sysmsi_priv {
+	struct device		*dev;
+	struct mbox_client	client;
+	struct mbox_chan	*chan;
+	u32			nr_irqs;
+	u32			gsi_base;
+};
+
+static int rpmi_sysmsi_get_num_msi(struct rpmi_sysmsi_priv *priv)
+{
+	struct rpmi_sysmsi_get_attrs_rx rx;
+	struct rpmi_mbox_message msg;
+	int ret;
+
+	rpmi_mbox_init_send_with_response(&msg, RPMI_SYSMSI_SRV_GET_ATTRIBUTES,
+					  NULL, 0, &rx, sizeof(rx));
+	ret = rpmi_mbox_send_message(priv->chan, &msg);
+	if (ret)
+		return ret;
+	if (rx.status)
+		return rpmi_to_linux_error(le32_to_cpu(rx.status));
+
+	return le32_to_cpu(rx.sys_num_msi);
+}
+
+static int rpmi_sysmsi_set_msi_state(struct rpmi_sysmsi_priv *priv,
+				     u32 sys_msi_index, u32 sys_msi_state)
+{
+	struct rpmi_sysmsi_set_msi_state_tx tx;
+	struct rpmi_sysmsi_set_msi_state_rx rx;
+	struct rpmi_mbox_message msg;
+	int ret;
+
+	tx.sys_msi_index = cpu_to_le32(sys_msi_index);
+	tx.sys_msi_state = cpu_to_le32(sys_msi_state);
+	rpmi_mbox_init_send_with_response(&msg, RPMI_SYSMSI_SRV_SET_MSI_STATE,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+	ret = rpmi_mbox_send_message(priv->chan, &msg);
+	if (ret)
+		return ret;
+	if (rx.status)
+		return rpmi_to_linux_error(le32_to_cpu(rx.status));
+
+	return 0;
+}
+
+static int rpmi_sysmsi_set_msi_target(struct rpmi_sysmsi_priv *priv,
+				      u32 sys_msi_index, struct msi_msg *m)
+{
+	struct rpmi_sysmsi_set_msi_target_tx tx;
+	struct rpmi_sysmsi_set_msi_target_rx rx;
+	struct rpmi_mbox_message msg;
+	int ret;
+
+	tx.sys_msi_index = cpu_to_le32(sys_msi_index);
+	tx.sys_msi_address_low = cpu_to_le32(m->address_lo);
+	tx.sys_msi_address_high = cpu_to_le32(m->address_hi);
+	tx.sys_msi_data = cpu_to_le32(m->data);
+	rpmi_mbox_init_send_with_response(&msg, RPMI_SYSMSI_SRV_SET_MSI_TARGET,
+					  &tx, sizeof(tx), &rx, sizeof(rx));
+	ret = rpmi_mbox_send_message(priv->chan, &msg);
+	if (ret)
+		return ret;
+	if (rx.status)
+		return rpmi_to_linux_error(le32_to_cpu(rx.status));
+
+	return 0;
+}
+
+static void rpmi_sysmsi_irq_mask(struct irq_data *d)
+{
+	struct rpmi_sysmsi_priv *priv = irq_data_get_irq_chip_data(d);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	int ret;
+
+	ret = rpmi_sysmsi_set_msi_state(priv, hwirq, 0);
+	if (ret)
+		dev_warn(priv->dev, "Failed to mask hwirq %lu (error %d)\n", hwirq, ret);
+	irq_chip_mask_parent(d);
+}
+
+static void rpmi_sysmsi_irq_unmask(struct irq_data *d)
+{
+	struct rpmi_sysmsi_priv *priv = irq_data_get_irq_chip_data(d);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	int ret;
+
+	irq_chip_unmask_parent(d);
+	ret = rpmi_sysmsi_set_msi_state(priv, hwirq, RPMI_SYSMSI_MSI_STATE_ENABLE);
+	if (ret)
+		dev_warn(priv->dev, "Failed to unmask hwirq %lu (error %d)\n", hwirq, ret);
+}
+
+static void rpmi_sysmsi_write_msg(struct irq_data *d, struct msi_msg *msg)
+{
+	struct rpmi_sysmsi_priv *priv = irq_data_get_irq_chip_data(d);
+	irq_hw_number_t hwirq = irqd_to_hwirq(d);
+	int ret;
+
+	/* For zeroed MSI, do nothing as of now */
+	if (!msg->address_hi && !msg->address_lo && !msg->data)
+		return;
+
+	ret = rpmi_sysmsi_set_msi_target(priv, hwirq, msg);
+	if (ret)
+		dev_warn(priv->dev, "Failed to set target for hwirq %lu (error %d)\n", hwirq, ret);
+}
+
+static void rpmi_sysmsi_set_desc(msi_alloc_info_t *arg, struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = desc->data.icookie.value;
+}
+
+static int rpmi_sysmsi_translate(struct irq_domain *d, struct irq_fwspec *fwspec,
+				 unsigned long *hwirq, unsigned int *type)
+{
+	struct msi_domain_info *info = d->host_data;
+	struct rpmi_sysmsi_priv *priv = info->data;
+
+	if (WARN_ON(fwspec->param_count < 1))
+		return -EINVAL;
+
+	/* For DT, gsi_base is always zero. */
+	*hwirq = fwspec->param[0] - priv->gsi_base;
+	*type = IRQ_TYPE_NONE;
+	return 0;
+}
+
+static const struct msi_domain_template rpmi_sysmsi_template = {
+	.chip = {
+		.name			= "RPMI-SYSMSI",
+		.irq_mask		= rpmi_sysmsi_irq_mask,
+		.irq_unmask		= rpmi_sysmsi_irq_unmask,
+#ifdef CONFIG_SMP
+		.irq_set_affinity	= irq_chip_set_affinity_parent,
+#endif
+		.irq_write_msi_msg	= rpmi_sysmsi_write_msg,
+		.flags			= IRQCHIP_SET_TYPE_MASKED |
+					  IRQCHIP_SKIP_SET_WAKE |
+					  IRQCHIP_MASK_ON_SUSPEND,
+	},
+
+	.ops = {
+		.set_desc		= rpmi_sysmsi_set_desc,
+		.msi_translate		= rpmi_sysmsi_translate,
+	},
+
+	.info = {
+		.bus_token		= DOMAIN_BUS_WIRED_TO_MSI,
+		.flags			= MSI_FLAG_USE_DEV_FWNODE,
+		.handler		= handle_simple_irq,
+		.handler_name		= "simple",
+	},
+};
+
+static int rpmi_sysmsi_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rpmi_sysmsi_priv *priv;
+	struct fwnode_handle *fwnode;
+	u32 id;
+	int rc;
+
+	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return -ENOMEM;
+	priv->dev = dev;
+
+	/* Setup mailbox client */
+	priv->client.dev		= priv->dev;
+	priv->client.rx_callback	= NULL;
+	priv->client.tx_block		= false;
+	priv->client.knows_txdone	= true;
+	priv->client.tx_tout		= 0;
+
+	/* Request mailbox channel */
+	priv->chan = mbox_request_channel(&priv->client, 0);
+	if (IS_ERR(priv->chan))
+		return PTR_ERR(priv->chan);
+
+	/* Get number of system MSIs */
+	rc = rpmi_sysmsi_get_num_msi(priv);
+	if (rc < 1) {
+		mbox_free_channel(priv->chan);
+		if (rc)
+			return dev_err_probe(dev, rc, "Failed to get number of system MSIs\n");
+		else
+			return dev_err_probe(dev, -ENODEV, "No system MSIs found\n");
+	}
+	priv->nr_irqs = rc;
+
+	fwnode = dev_fwnode(dev);
+	if (is_acpi_node(fwnode)) {
+		u32 nr_irqs;
+
+		rc = riscv_acpi_get_gsi_info(fwnode, &priv->gsi_base, &id,
+					     &nr_irqs, NULL);
+		if (rc) {
+			dev_err(dev, "failed to find GSI mapping\n");
+			return rc;
+		}
+
+		/* Update with actual GSI range */
+		if (nr_irqs != priv->nr_irqs)
+			riscv_acpi_update_gsi_range(priv->gsi_base, priv->nr_irqs);
+	}
+
+	/*
+	 * The device MSI domain for platform devices on RISC-V architecture
+	 * is only available after the MSI controller driver is probed so,
+	 * explicitly configure here.
+	 */
+	if (!dev_get_msi_domain(dev)) {
+		/*
+		 * The device MSI domain for OF devices is only set at the
+		 * time of populating/creating OF device. If the device MSI
+		 * domain is discovered later after the OF device is created
+		 * then we need to set it explicitly before using any platform
+		 * MSI functions.
+		 */
+		if (is_of_node(fwnode)) {
+			of_msi_configure(dev, dev_of_node(dev));
+		} else if (is_acpi_device_node(fwnode)) {
+			struct irq_domain *msi_domain;
+
+			msi_domain = irq_find_matching_fwnode(imsic_acpi_get_fwnode(dev),
+							      DOMAIN_BUS_PLATFORM_MSI);
+			dev_set_msi_domain(dev, msi_domain);
+		}
+
+		if (!dev_get_msi_domain(dev)) {
+			mbox_free_channel(priv->chan);
+			return -EPROBE_DEFER;
+		}
+	}
+
+	if (!msi_create_device_irq_domain(dev, MSI_DEFAULT_DOMAIN,
+					  &rpmi_sysmsi_template,
+					  priv->nr_irqs, priv, priv)) {
+		mbox_free_channel(priv->chan);
+		return dev_err_probe(dev, -ENOMEM, "failed to create MSI irq domain\n");
+	}
+
+#ifdef CONFIG_ACPI
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (adev)
+		acpi_dev_clear_dependencies(adev);
+#endif
+
+	dev_info(dev, "%u system MSIs registered\n", priv->nr_irqs);
+	return 0;
+}
+
+static const struct of_device_id rpmi_sysmsi_match[] = {
+	{ .compatible = "riscv,rpmi-system-msi" },
+	{}
+};
+
+static const struct acpi_device_id acpi_rpmi_sysmsi_match[] = {
+	{ "RSCV0006" },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, acpi_rpmi_sysmsi_match);
+
+static struct platform_driver rpmi_sysmsi_driver = {
+	.driver = {
+		.name			= "rpmi-sysmsi",
+		.of_match_table		= rpmi_sysmsi_match,
+		.acpi_match_table	= acpi_rpmi_sysmsi_match,
+	},
+	.probe = rpmi_sysmsi_probe,
+};
+builtin_platform_driver(rpmi_sysmsi_driver);

drivers/mailbox/Kconfig

···
 	  processor and coprocessor that handles various power management task
 	  and more.
 
+config RISCV_SBI_MPXY_MBOX
+	tristate "RISC-V SBI Message Proxy (MPXY) Mailbox"
+	depends on RISCV_SBI
+	default RISCV
+	help
+	  Mailbox driver implementation for RISC-V SBI Message Proxy (MPXY)
+	  extension. This mailbox driver is used to send messages to the
+	  remote processor through the SBI implementation (M-mode firmware
+	  or HS-mode hypervisor). Say Y here if you want to have this support.
+	  If unsure say N.
+
 endif

drivers/mailbox/Makefile

···
 obj-$(CONFIG_CIX_MBOX)	+= cix-mailbox.o
 
 obj-$(CONFIG_BCM74110_MAILBOX)	+= bcm74110-mailbox.o
+
+obj-$(CONFIG_RISCV_SBI_MPXY_MBOX)	+= riscv-sbi-mpxy-mbox.o

drivers/mailbox/mailbox.c

···
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/of.h>
+#include <linux/property.h>
 #include <linux/spinlock.h>
 
 #include "mailbox.h"
···
  */
 struct mbox_chan *mbox_request_channel(struct mbox_client *cl, int index)
 {
-	struct device *dev = cl->dev;
+	struct fwnode_reference_args fwspec;
+	struct fwnode_handle *fwnode;
 	struct mbox_controller *mbox;
 	struct of_phandle_args spec;
 	struct mbox_chan *chan;
+	struct device *dev;
+	unsigned int i;
 	int ret;
 
-	if (!dev || !dev->of_node) {
-		pr_debug("%s: No owner device node\n", __func__);
+	dev = cl->dev;
+	if (!dev) {
+		pr_debug("No owner device\n");
 		return ERR_PTR(-ENODEV);
 	}
 
-	ret = of_parse_phandle_with_args(dev->of_node, "mboxes", "#mbox-cells",
-					 index, &spec);
+	fwnode = dev_fwnode(dev);
+	if (!fwnode) {
+		dev_dbg(dev, "No owner fwnode\n");
+		return ERR_PTR(-ENODEV);
+	}
+
+	ret = fwnode_property_get_reference_args(fwnode, "mboxes", "#mbox-cells",
+						 0, index, &fwspec);
 	if (ret) {
-		dev_err(dev, "%s: can't parse \"mboxes\" property\n", __func__);
+		dev_err(dev, "%s: can't parse \"%s\" property\n", __func__, "mboxes");
 		return ERR_PTR(ret);
 	}
 
+	spec.np = to_of_node(fwspec.fwnode);
+	spec.args_count = fwspec.nargs;
+	for (i = 0; i < spec.args_count; i++)
+		spec.args[i] = fwspec.args[i];
+
 	scoped_guard(mutex, &con_mutex) {
 		chan = ERR_PTR(-EPROBE_DEFER);
-		list_for_each_entry(mbox, &mbox_cons, node)
-			if (mbox->dev->of_node == spec.np) {
-				chan = mbox->of_xlate(mbox, &spec);
-				if (!IS_ERR(chan))
-					break;
+		list_for_each_entry(mbox, &mbox_cons, node) {
+			if (device_match_fwnode(mbox->dev, fwspec.fwnode)) {
+				if (mbox->fw_xlate) {
+					chan = mbox->fw_xlate(mbox, &fwspec);
+					if (!IS_ERR(chan))
+						break;
+				} else if (mbox->of_xlate) {
+					chan = mbox->of_xlate(mbox, &spec);
+					if (!IS_ERR(chan))
+						break;
+				}
 			}
+		}
 
-		of_node_put(spec.np);
+		fwnode_handle_put(fwspec.fwnode);
 
 		if (IS_ERR(chan))
 			return chan;
···
 struct mbox_chan *mbox_request_channel_byname(struct mbox_client *cl,
 					      const char *name)
 {
-	struct device_node *np = cl->dev->of_node;
-	int index;
+	int index = device_property_match_string(cl->dev, "mbox-names", name);
 
-	if (!np) {
-		dev_err(cl->dev, "%s() currently only supports DT\n", __func__);
-		return ERR_PTR(-EINVAL);
-	}
-
-	index = of_property_match_string(np, "mbox-names", name);
 	if (index < 0) {
 		dev_err(cl->dev, "%s() could not locate channel named \"%s\"\n",
 			__func__, name);
···
 }
 EXPORT_SYMBOL_GPL(mbox_free_channel);
 
-static struct mbox_chan *
-of_mbox_index_xlate(struct mbox_controller *mbox,
-		    const struct of_phandle_args *sp)
+static struct mbox_chan *fw_mbox_index_xlate(struct mbox_controller *mbox,
+					     const struct fwnode_reference_args *sp)
 {
 	int ind = sp->args[0];
 
···
 		spin_lock_init(&chan->lock);
 	}
 
-	if (!mbox->of_xlate)
-		mbox->of_xlate = of_mbox_index_xlate;
+	if (!mbox->fw_xlate && !mbox->of_xlate)
+		mbox->fw_xlate = fw_mbox_index_xlate;
 
 	scoped_guard(mutex, &con_mutex)
 		list_add_tail(&mbox->node, &mbox_cons);

drivers/mailbox/riscv-sbi-mpxy-mbox.c

···
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * RISC-V SBI Message Proxy (MPXY) mailbox controller driver
+ *
+ * Copyright (C) 2025 Ventana Micro Systems Inc.
+ */
+
+#include <linux/acpi.h>
+#include <linux/cpu.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/irqchip/riscv-imsic.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox/riscv-rpmi-message.h>
+#include <linux/minmax.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/of_irq.h>
+#include <linux/percpu.h>
+#include <linux/platform_device.h>
+#include <linux/smp.h>
+#include <linux/string.h>
+#include <linux/types.h>
+#include <asm/byteorder.h>
+#include <asm/sbi.h>
+
+/* ====== SBI MPXY extension data structures ====== */
+
+/* SBI MPXY MSI related channel attributes */
+struct sbi_mpxy_msi_info {
+	/* Lower 32-bits of the MSI target address */
+	u32 msi_addr_lo;
+	/* Upper 32-bits of the MSI target address */
+	u32 msi_addr_hi;
+	/* MSI data value */
+	u32 msi_data;
+};
+
+/*
+ * SBI MPXY standard channel attributes.
+ *
+ * NOTE: The sequence of attribute fields are as-per the
+ * defined sequence in the attribute table in spec (or
+ * as-per the enum sbi_mpxy_attribute_id).
+ */
+struct sbi_mpxy_channel_attrs {
+	/* Message protocol ID */
+	u32 msg_proto_id;
+	/* Message protocol version */
+	u32 msg_proto_version;
+	/* Message protocol maximum message length */
+	u32 msg_max_len;
+	/* Message protocol message send timeout in microseconds */
+	u32 msg_send_timeout;
+	/* Message protocol message completion timeout in microseconds */
+	u32 msg_completion_timeout;
+	/* Bit array for channel capabilities */
+	u32 capability;
+	/* SSE event ID */
+	u32 sse_event_id;
+	/* MSI enable/disable control knob */
+	u32 msi_control;
+	/* Channel MSI info */
+	struct sbi_mpxy_msi_info msi_info;
+	/* Events state control */
+	u32 events_state_ctrl;
+};
+
+/*
+ * RPMI specific SBI MPXY channel attributes.
+ *
+ * NOTE: The sequence of attribute fields are as-per the
+ * defined sequence in the attribute table in spec (or
+ * as-per the enum sbi_mpxy_rpmi_attribute_id).
+ */
+struct sbi_mpxy_rpmi_channel_attrs {
+	/* RPMI service group ID */
+	u32 servicegroup_id;
+	/* RPMI service group version */
+	u32 servicegroup_version;
+	/* RPMI implementation ID */
+	u32 impl_id;
+	/* RPMI implementation version */
+	u32 impl_version;
+};
+
+/* SBI MPXY channel IDs data in shared memory */
+struct sbi_mpxy_channel_ids_data {
+	/* Remaining number of channel ids */
+	__le32 remaining;
+	/* Returned channel ids in current function call */
+	__le32 returned;
+	/* Returned channel id array */
+	__le32 channel_array[];
+};
+
+/* SBI MPXY notification data in shared memory */
+struct sbi_mpxy_notification_data {
+	/* Remaining number of notification events */
+	__le32 remaining;
+	/* Number of notification events returned */
+	__le32 returned;
+	/* Number of notification events lost */
+	__le32 lost;
+	/* Reserved for future use */
+	__le32 reserved;
+	/* Returned channel id array */
+	u8 events_data[];
+};
+
+/* ====== MPXY data structures & helper routines ====== */
+
+/* MPXY Per-CPU or local context */
+struct mpxy_local {
+	/* Shared memory base address */
+	void *shmem;
+	/* Shared memory physical address */
+	phys_addr_t shmem_phys_addr;
+	/* Flag representing whether shared memory is active or not */
+	bool shmem_active;
+};
+
+static DEFINE_PER_CPU(struct mpxy_local, mpxy_local);
+static unsigned long mpxy_shmem_size;
+static bool mpxy_shmem_init_done;
+
+static int mpxy_get_channel_count(u32 *channel_count)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbi_mpxy_channel_ids_data *sdata = mpxy->shmem;
+	u32 remaining, returned;
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!channel_count)
+		return -EINVAL;
+
+	get_cpu();
+
+	/* Get the remaining and returned fields to calculate total */
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_GET_CHANNEL_IDS,
+			 0, 0, 0, 0, 0, 0);
+	if (sret.error)
+		goto err_put_cpu;
+
+	remaining = le32_to_cpu(sdata->remaining);
+	returned = le32_to_cpu(sdata->returned);
+	*channel_count = remaining + returned;
+
+err_put_cpu:
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_get_channel_ids(u32 channel_count, u32 *channel_ids)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbi_mpxy_channel_ids_data *sdata = mpxy->shmem;
+	u32 remaining, returned, count, start_index = 0;
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!channel_count || !channel_ids)
+		return -EINVAL;
+
+	get_cpu();
+
+	do {
+		sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_GET_CHANNEL_IDS,
+				 start_index, 0, 0, 0, 0, 0);
+		if (sret.error)
+			goto err_put_cpu;
+
+		remaining = le32_to_cpu(sdata->remaining);
+		returned = le32_to_cpu(sdata->returned);
+
+		count = returned < (channel_count - start_index) ?
+			returned : (channel_count - start_index);
+		memcpy_from_le32(&channel_ids[start_index], sdata->channel_array, count);
+		start_index += count;
+	} while (remaining && start_index < channel_count);
+
+err_put_cpu:
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_read_attrs(u32 channel_id, u32 base_attrid, u32 attr_count,
+			   u32 *attrs_buf)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!attr_count || !attrs_buf)
+		return -EINVAL;
+
+	get_cpu();
+
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_READ_ATTRS,
+			 channel_id, base_attrid, attr_count, 0, 0, 0);
+	if (sret.error)
+		goto err_put_cpu;
+
+	memcpy_from_le32(attrs_buf, (__le32 *)mpxy->shmem, attr_count);
+
+err_put_cpu:
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_write_attrs(u32 channel_id, u32 base_attrid, u32 attr_count,
+			    u32 *attrs_buf)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!attr_count || !attrs_buf)
+		return -EINVAL;
+
+	get_cpu();
+
+	memcpy_to_le32((__le32 *)mpxy->shmem, attrs_buf, attr_count);
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_WRITE_ATTRS,
+			 channel_id, base_attrid, attr_count, 0, 0, 0);
+
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_send_message_with_resp(u32 channel_id, u32 msg_id,
+				       void *tx, unsigned long tx_len,
+				       void *rx, unsigned long max_rx_len,
+				       unsigned long *rx_len)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	unsigned long rx_bytes;
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!tx && tx_len)
+		return -EINVAL;
+
+	get_cpu();
+
+	/* Message protocols allowed to have no data in messages */
+	if (tx_len)
+		memcpy(mpxy->shmem, tx, tx_len);
+
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_SEND_MSG_WITH_RESP,
+			 channel_id, msg_id, tx_len, 0, 0, 0);
+	if (rx && !sret.error) {
+		rx_bytes = sret.value;
+		if (rx_bytes > max_rx_len) {
+			put_cpu();
+			return -ENOSPC;
+		}
+
+		memcpy(rx, mpxy->shmem, rx_bytes);
+		if (rx_len)
+			*rx_len = rx_bytes;
+	}
+
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_send_message_without_resp(u32 channel_id, u32 msg_id,
+					  void *tx, unsigned long tx_len)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!tx && tx_len)
+		return -EINVAL;
+
+	get_cpu();
+
+	/* Message protocols allowed to have no data in messages */
+	if (tx_len)
+		memcpy(mpxy->shmem, tx, tx_len);
+
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_SEND_MSG_WITHOUT_RESP,
+			 channel_id, msg_id, tx_len, 0, 0, 0);
+
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_get_notifications(u32 channel_id,
+				  struct sbi_mpxy_notification_data *notif_data,
+				  unsigned long *events_data_len)
+{
+	struct mpxy_local *mpxy = this_cpu_ptr(&mpxy_local);
+	struct sbiret sret;
+
+	if (!mpxy->shmem_active)
+		return -ENODEV;
+	if (!notif_data || !events_data_len)
+		return -EINVAL;
+
+	get_cpu();
+
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_GET_NOTIFICATION_EVENTS,
+			 channel_id, 0, 0, 0, 0, 0);
+	if (sret.error)
+		goto err_put_cpu;
+
+	memcpy(notif_data, mpxy->shmem, sret.value + 16);
+	*events_data_len = sret.value;
+
+err_put_cpu:
+	put_cpu();
+	return sbi_err_map_linux_errno(sret.error);
+}
+
+static int mpxy_get_shmem_size(unsigned long *shmem_size)
+{
+	struct sbiret sret;
+
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_GET_SHMEM_SIZE,
+			 0, 0, 0, 0, 0, 0);
+	if (sret.error)
+		return sbi_err_map_linux_errno(sret.error);
+	if (shmem_size)
+		*shmem_size = sret.value;
+	return 0;
+}
+
+static int mpxy_setup_shmem(unsigned int cpu)
+{
+	struct page *shmem_page;
+	struct mpxy_local *mpxy;
+	struct sbiret sret;
+
+	mpxy = per_cpu_ptr(&mpxy_local, cpu);
+	if (mpxy->shmem_active)
+		return 0;
+
+	shmem_page = alloc_pages(GFP_KERNEL | __GFP_ZERO, get_order(mpxy_shmem_size));
+	if (!shmem_page)
+		return -ENOMEM;
+
+	/*
+	 * Linux setup of shmem is done in mpxy OVERWRITE mode.
+	 * flags[1:0] = 00b
+	 */
+	sret = sbi_ecall(SBI_EXT_MPXY, SBI_EXT_MPXY_SET_SHMEM,
+			 page_to_phys(shmem_page), 0, 0, 0, 0, 0);
+	if (sret.error) {
+		free_pages((unsigned long)page_to_virt(shmem_page),
+			   get_order(mpxy_shmem_size));
+		return sbi_err_map_linux_errno(sret.error);
+	}
+
+	mpxy->shmem = page_to_virt(shmem_page);
+	mpxy->shmem_phys_addr = page_to_phys(shmem_page);
+	mpxy->shmem_active = true;
+
+	return 0;
+}
+
+/* ====== MPXY mailbox data structures ====== */
+
+/* MPXY mailbox channel */
+struct mpxy_mbox_channel {
+	struct mpxy_mbox *mbox;
+	u32 channel_id;
+	struct sbi_mpxy_channel_attrs attrs;
+	struct sbi_mpxy_rpmi_channel_attrs rpmi_attrs;
+	struct sbi_mpxy_notification_data *notif;
+	u32 max_xfer_len;
+	bool have_events_state;
+	u32 msi_index;
+	u32 msi_irq;
+	bool started;
+};
+
+/* MPXY mailbox */
+struct mpxy_mbox {
+	struct device *dev;
+	u32 channel_count;
+	struct mpxy_mbox_channel *channels;
+	u32 msi_count;
+	struct mpxy_mbox_channel **msi_index_to_channel;
+	struct mbox_controller controller;
+};
+
+/* ====== MPXY RPMI processing ====== */
+
+static void mpxy_mbox_send_rpmi_data(struct mpxy_mbox_channel *mchan,
+				     struct rpmi_mbox_message *msg)
+{
+	msg->error = 0;
+	switch (msg->type) {
+	case RPMI_MBOX_MSG_TYPE_GET_ATTRIBUTE:
+		switch (msg->attr.id) {
+		case RPMI_MBOX_ATTR_SPEC_VERSION:
+			msg->attr.value = mchan->attrs.msg_proto_version;
+			break;
+		case RPMI_MBOX_ATTR_MAX_MSG_DATA_SIZE:
+			msg->attr.value = mchan->max_xfer_len;
+			break;
+		case RPMI_MBOX_ATTR_SERVICEGROUP_ID:
+			msg->attr.value = mchan->rpmi_attrs.servicegroup_id;
+			break;
+		case RPMI_MBOX_ATTR_SERVICEGROUP_VERSION:
+			msg->attr.value = mchan->rpmi_attrs.servicegroup_version;
+			break;
+		case RPMI_MBOX_ATTR_IMPL_ID:
+			msg->attr.value = mchan->rpmi_attrs.impl_id;
+			break;
+		case RPMI_MBOX_ATTR_IMPL_VERSION:
+			msg->attr.value = mchan->rpmi_attrs.impl_version;
+			break;
+		default:
+			msg->error = -EOPNOTSUPP;
+			break;
+		}
+		break;
+	case RPMI_MBOX_MSG_TYPE_SET_ATTRIBUTE:
+		/* None of the RPMI linux mailbox attributes are writeable */
+		msg->error = -EOPNOTSUPP;
+		break;
+	case RPMI_MBOX_MSG_TYPE_SEND_WITH_RESPONSE:
+		if ((!msg->data.request && msg->data.request_len) ||
+		    (msg->data.request && msg->data.request_len > mchan->max_xfer_len) ||
+		    (!msg->data.response && msg->data.max_response_len)) {
+			msg->error = -EINVAL;
+			break;
+		}
+		if (!(mchan->attrs.capability & SBI_MPXY_CHAN_CAP_SEND_WITH_RESP)) {
+			msg->error = -EIO;
+			break;
+		}
+		msg->error = mpxy_send_message_with_resp(mchan->channel_id,
+							 msg->data.service_id,
+							 msg->data.request,
+							 msg->data.request_len,
+							 msg->data.response,
+							 msg->data.max_response_len,
+							 &msg->data.out_response_len);
+		break;
+	case RPMI_MBOX_MSG_TYPE_SEND_WITHOUT_RESPONSE:
+		if ((!msg->data.request && msg->data.request_len) ||
+		    (msg->data.request && msg->data.request_len > mchan->max_xfer_len)) {
+			msg->error = -EINVAL;
+			break;
+		}
+		if (!(mchan->attrs.capability & SBI_MPXY_CHAN_CAP_SEND_WITHOUT_RESP)) {
+			msg->error = -EIO;
+			break;
+		}
+		msg->error = mpxy_send_message_without_resp(mchan->channel_id,
+							    msg->data.service_id,
+							    msg->data.request,
+							    msg->data.request_len);
+		break;
+	default:
+		msg->error = -EOPNOTSUPP;
+		break;
+	}
+}
+
+static void mpxy_mbox_peek_rpmi_data(struct mbox_chan *chan,
+				     struct mpxy_mbox_channel *mchan,
+				     struct sbi_mpxy_notification_data *notif,
+				     unsigned long events_data_len)
+{
+	struct rpmi_notification_event *event;
+	struct rpmi_mbox_message msg;
+	unsigned long pos = 0;
+
+	while (pos < events_data_len && (events_data_len - pos) <= sizeof(*event)) {
+		event = (struct rpmi_notification_event *)(notif->events_data + pos);
+
+		msg.type = RPMI_MBOX_MSG_TYPE_NOTIFICATION_EVENT;
+		msg.notif.event_datalen = le16_to_cpu(event->event_datalen);
+		msg.notif.event_id = event->event_id;
+		msg.notif.event_data = event->event_data;
+		msg.error = 0;
+
+		mbox_chan_received_data(chan, &msg);
+		pos += sizeof(*event) + msg.notif.event_datalen;
+	}
+}
+
+static int mpxy_mbox_read_rpmi_attrs(struct mpxy_mbox_channel *mchan)
+{
+	return mpxy_read_attrs(mchan->channel_id,
+			       SBI_MPXY_ATTR_MSGPROTO_ATTR_START,
+			       sizeof(mchan->rpmi_attrs) / sizeof(u32),
+			       (u32 *)&mchan->rpmi_attrs);
+}
+
+/* ====== MPXY mailbox callbacks ====== */
+
+static int mpxy_mbox_send_data(struct mbox_chan *chan, void *data)
+{
+	struct mpxy_mbox_channel *mchan = chan->con_priv;
+
+	if (mchan->attrs.msg_proto_id == SBI_MPXY_MSGPROTO_RPMI_ID) {
+		mpxy_mbox_send_rpmi_data(mchan, data);
+		return 0;
+	}
+
+	return -EOPNOTSUPP;
+}
+
+static bool mpxy_mbox_peek_data(struct mbox_chan *chan)
+{
+	struct mpxy_mbox_channel *mchan = chan->con_priv;
+	struct sbi_mpxy_notification_data *notif = mchan->notif;
+	bool have_notifications = false;
+	unsigned long data_len;
+	int rc;
+
+	if (!(mchan->attrs.capability & SBI_MPXY_CHAN_CAP_GET_NOTIFICATIONS))
+		return false;
+
+	do {
+		rc = mpxy_get_notifications(mchan->channel_id, notif, &data_len);
+		if (rc || !data_len)
+			break;
+
+		if (mchan->attrs.msg_proto_id == SBI_MPXY_MSGPROTO_RPMI_ID)
+			mpxy_mbox_peek_rpmi_data(chan, mchan, notif, data_len);
+
+		have_notifications = true;
+	} while (1);
+
+	return have_notifications;
+}
+
+static irqreturn_t mpxy_mbox_irq_thread(int irq, void *dev_id)
+{
+	mpxy_mbox_peek_data(dev_id);
+	return IRQ_HANDLED;
+}
+
+static int mpxy_mbox_setup_msi(struct mbox_chan *chan,
+			       struct mpxy_mbox_channel *mchan)
+{
+	struct device *dev = mchan->mbox->dev;
+	int rc;
+
+	/* Do nothing if MSI not supported */
+	if (mchan->msi_irq == U32_MAX)
+		return 0;
+
+	/* Fail if MSI already enabled */
+	if (mchan->attrs.msi_control)
+		return -EALREADY;
+
+	/* Request channel MSI handler */
+	rc = request_threaded_irq(mchan->msi_irq, NULL, mpxy_mbox_irq_thread,
+				  0, dev_name(dev), chan);
+	if (rc) {
+		dev_err(dev, "failed to request MPXY channel 0x%x IRQ\n",
+			mchan->channel_id);
+		return rc;
+	}
+
+	/* Enable channel MSI control */
+	mchan->attrs.msi_control = 1;
+	rc = mpxy_write_attrs(mchan->channel_id, SBI_MPXY_ATTR_MSI_CONTROL,
+			      1, &mchan->attrs.msi_control);
+	if (rc) {
+		dev_err(dev, "enable MSI control failed for MPXY channel 0x%x\n",
+			mchan->channel_id);
+		mchan->attrs.msi_control = 0;
+		free_irq(mchan->msi_irq, chan);
+		return rc;
+	}
+
+	return 0;
+}
+
+static void mpxy_mbox_cleanup_msi(struct mbox_chan *chan,
+				  struct mpxy_mbox_channel *mchan)
+{
+	struct device *dev = mchan->mbox->dev;
+	int rc;
+
+	/* Do nothing if MSI not supported */
+	if (mchan->msi_irq == U32_MAX)
+		return;
+
+	/* Do nothing if MSI already disabled */
+	if (!mchan->attrs.msi_control)
+		return;
+
+	/* Disable channel MSI control */
+	mchan->attrs.msi_control = 0;
+	rc = mpxy_write_attrs(mchan->channel_id, SBI_MPXY_ATTR_MSI_CONTROL,
+			      1, &mchan->attrs.msi_control);
+	if (rc) {
+		dev_err(dev, "disable MSI control failed for MPXY channel 0x%x\n",
+			mchan->channel_id);
+	}
+
+	/* Free channel MSI handler */
+	free_irq(mchan->msi_irq, chan);
+}
+
+static int mpxy_mbox_setup_events(struct mpxy_mbox_channel *mchan)
+{
+	struct device *dev = mchan->mbox->dev;
+	int rc;
+
+	/* Do nothing if events state not supported */
+	if (!mchan->have_events_state)
+		return 0;
+
+	/* Fail if events state already enabled */
+	if (mchan->attrs.events_state_ctrl)
+		return -EALREADY;
+
+	/* Enable channel events state */
+	mchan->attrs.events_state_ctrl = 1;
+	rc = mpxy_write_attrs(mchan->channel_id, SBI_MPXY_ATTR_EVENTS_STATE_CONTROL,
+			      1, &mchan->attrs.events_state_ctrl);
+	if (rc) {
+		dev_err(dev, "enable events state failed for MPXY channel 0x%x\n",
+			mchan->channel_id);
+		mchan->attrs.events_state_ctrl = 0;
+		return rc;
+	}
+
+	return 0;
+}
+
+static void mpxy_mbox_cleanup_events(struct mpxy_mbox_channel *mchan)
+{
+	struct device *dev = mchan->mbox->dev;
+	int rc;
+
+	/* Do nothing if events state not supported */
+	if (!mchan->have_events_state)
+		return;
+
+	/* Do nothing if events state already disabled */
+	if (!mchan->attrs.events_state_ctrl)
+		return;
+
+	/* Disable channel events state */
+	mchan->attrs.events_state_ctrl = 0;
+	rc = mpxy_write_attrs(mchan->channel_id, SBI_MPXY_ATTR_EVENTS_STATE_CONTROL,
+			      1, &mchan->attrs.events_state_ctrl);
+	if (rc)
+		dev_err(dev, "disable events state failed for MPXY channel 0x%x\n",
+			mchan->channel_id);
+}
+
+static int mpxy_mbox_startup(struct mbox_chan *chan)
+{
+	struct mpxy_mbox_channel *mchan = chan->con_priv;
+	int rc;
+
+	if (mchan->started)
+		return -EALREADY;
+
+	/* Setup channel MSI */
+	rc = mpxy_mbox_setup_msi(chan, mchan);
+	if (rc)
+		return rc;
+
+	/* Setup channel notification events */
+	rc = mpxy_mbox_setup_events(mchan);
+	if (rc) {
+		mpxy_mbox_cleanup_msi(chan, mchan);
+		return rc;
+	}
+
+	/* Mark the channel as started */
+	mchan->started = true;
+
+	return 0;
+}
+
+static void mpxy_mbox_shutdown(struct mbox_chan *chan)
+{
+	struct mpxy_mbox_channel *mchan = chan->con_priv;
+
+	if (!mchan->started)
+		return;
+
+	/* Mark the channel as stopped */
+	mchan->started = false;
+
+	/* Cleanup channel notification events */
+	mpxy_mbox_cleanup_events(mchan);
+
+	/* Cleanup channel MSI */
+	mpxy_mbox_cleanup_msi(chan, mchan);
+}
+
+static const struct mbox_chan_ops mpxy_mbox_ops = {
+	.send_data = mpxy_mbox_send_data,
+	.peek_data = mpxy_mbox_peek_data,
+	.startup = mpxy_mbox_startup,
+	.shutdown = mpxy_mbox_shutdown,
+};
+
+/* ====== MPXY platform driver ===== */
+
+static void mpxy_mbox_msi_write(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct device *dev = msi_desc_to_dev(desc);
+	struct mpxy_mbox *mbox = dev_get_drvdata(dev);
+	struct mpxy_mbox_channel *mchan;
+	struct sbi_mpxy_msi_info *minfo;
+	int rc;
+
+	mchan = mbox->msi_index_to_channel[desc->msi_index];
+	if (!mchan) {
+		dev_warn(dev, "MPXY channel not available for MSI index %d\n",
+			 desc->msi_index);
+		return;
+	}
+
+	minfo = &mchan->attrs.msi_info;
+	minfo->msi_addr_lo = msg->address_lo;
+	minfo->msi_addr_hi = msg->address_hi;
+	minfo->msi_data = msg->data;
+
+	rc = mpxy_write_attrs(mchan->channel_id, SBI_MPXY_ATTR_MSI_ADDR_LO,
+			      sizeof(*minfo) / sizeof(u32), (u32 *)minfo);
+	if (rc) {
+		dev_warn(dev, "failed to write MSI info for MPXY channel 0x%x\n",
+			 mchan->channel_id);
+	}
+}
+
+static struct mbox_chan *mpxy_mbox_fw_xlate(struct mbox_controller *ctlr,
+					    const struct fwnode_reference_args *pa)
+{
+	struct mpxy_mbox *mbox = container_of(ctlr, struct mpxy_mbox, controller);
+	struct mpxy_mbox_channel *mchan;
+	u32 i;
+
+	if (pa->nargs != 2)
+		return ERR_PTR(-EINVAL);
+
+	for (i = 0; i < mbox->channel_count; i++) {
+		mchan = &mbox->channels[i];
+		if (mchan->channel_id == pa->args[0] &&
+		    mchan->attrs.msg_proto_id == pa->args[1])
+			return &mbox->controller.chans[i];
+	}
+
+	return ERR_PTR(-ENOENT);
+}
+
+static int mpxy_mbox_populate_channels(struct mpxy_mbox *mbox)
+{
+	u32 i, *channel_ids __free(kfree) = NULL;
+	struct mpxy_mbox_channel *mchan;
+	int rc;
+
+	/* Find-out of number of channels */
+	rc = mpxy_get_channel_count(&mbox->channel_count);
+	if (rc)
+		return dev_err_probe(mbox->dev, rc, "failed to get number of MPXY channels\n");
+	if (!mbox->channel_count)
+		return dev_err_probe(mbox->dev, -ENODEV, "no MPXY channels available\n");
+
+	/* Allocate and fetch all channel IDs */
+	channel_ids = kcalloc(mbox->channel_count, sizeof(*channel_ids), GFP_KERNEL);
+	if (!channel_ids)
+		return -ENOMEM;
+	rc = mpxy_get_channel_ids(mbox->channel_count, channel_ids);
+	if (rc)
+		return dev_err_probe(mbox->dev, rc, "failed to get MPXY channel IDs\n");
+
+	/* Populate all channels */
+	mbox->channels = devm_kcalloc(mbox->dev, mbox->channel_count,
+				      sizeof(*mbox->channels), GFP_KERNEL);
+	if (!mbox->channels)
+		return -ENOMEM;
+	for (i = 0; i < mbox->channel_count; i++) {
+		mchan = &mbox->channels[i];
+		mchan->mbox = mbox;
+		mchan->channel_id = channel_ids[i];
+
+		rc = mpxy_read_attrs(mchan->channel_id, SBI_MPXY_ATTR_MSG_PROT_ID,
+				     sizeof(mchan->attrs) / sizeof(u32),
+				     (u32 *)&mchan->attrs);
+		if (rc) {
+			return dev_err_probe(mbox->dev, rc,
+					     "MPXY channel 0x%x read attrs failed\n",
+					     mchan->channel_id);
+		}
+
+		if (mchan->attrs.msg_proto_id == SBI_MPXY_MSGPROTO_RPMI_ID) {
+			rc = mpxy_mbox_read_rpmi_attrs(mchan);
+			if (rc) {
+				return dev_err_probe(mbox->dev, rc,
+						     "MPXY channel 0x%x read RPMI attrs failed\n",
+						     mchan->channel_id);
+			}
+		}
+
+		mchan->notif = devm_kzalloc(mbox->dev, mpxy_shmem_size, GFP_KERNEL);
+		if (!mchan->notif)
+			return -ENOMEM;
+
+		mchan->max_xfer_len = min(mpxy_shmem_size, mchan->attrs.msg_max_len);
+
+		if ((mchan->attrs.capability & SBI_MPXY_CHAN_CAP_GET_NOTIFICATIONS) &&
+		    (mchan->attrs.capability & SBI_MPXY_CHAN_CAP_EVENTS_STATE))
+			mchan->have_events_state = true;
+
+		if ((mchan->attrs.capability & SBI_MPXY_CHAN_CAP_GET_NOTIFICATIONS) &&
+		    (mchan->attrs.capability & SBI_MPXY_CHAN_CAP_MSI))
+			mchan->msi_index = mbox->msi_count++;
+		else
+			mchan->msi_index = U32_MAX;
+		mchan->msi_irq = U32_MAX;
+	}
+
+	return 0;
+}
+
+static int mpxy_mbox_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct mpxy_mbox_channel *mchan;
+	struct mpxy_mbox *mbox;
+	int msi_idx, rc;
+	u32 i;
+
+	/*
+	 * Initialize MPXY shared memory only once. This also ensures
+	 * that SBI MPXY mailbox is probed only once.
+	 */
+	if (mpxy_shmem_init_done) {
+		dev_err(dev, "SBI MPXY mailbox already initialized\n");
+		return -EALREADY;
+	}
+
+	/* Probe for SBI MPXY extension */
+	if (sbi_spec_version < sbi_mk_version(1, 0) ||
+	    sbi_probe_extension(SBI_EXT_MPXY) <= 0) {
+		dev_info(dev, "SBI MPXY extension not available\n");
+		return -ENODEV;
+	}
+
+	/* Find-out shared memory size */
+	rc = mpxy_get_shmem_size(&mpxy_shmem_size);
+	if (rc)
+		return dev_err_probe(dev, rc, "failed to get MPXY shared memory size\n");
+
+	/*
+	 * Setup MPXY shared memory on each CPU
+	 *
+	 * Note: Don't cleanup MPXY shared memory upon CPU power-down
+	 * because the RPMI System MSI irqchip driver needs it to be
+	 * available when migrating IRQs in CPU power-down path.
+	 */
+	cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "riscv/sbi-mpxy-shmem",
+			  mpxy_setup_shmem, NULL);
+
+	/* Mark as MPXY shared memory initialization done */
+	mpxy_shmem_init_done = true;
+
+	/* Allocate mailbox instance */
+	mbox = devm_kzalloc(dev, sizeof(*mbox), GFP_KERNEL);
+	if (!mbox)
+		return -ENOMEM;
+	mbox->dev = dev;
+	platform_set_drvdata(pdev, mbox);
+
+	/* Populate mailbox channels */
+	rc = mpxy_mbox_populate_channels(mbox);
+	if (rc)
+		return rc;
+
+	/* Initialize mailbox controller */
+	mbox->controller.txdone_irq = false;
+	mbox->controller.txdone_poll = false;
+	mbox->controller.ops = &mpxy_mbox_ops;
+	mbox->controller.dev = dev;
+	mbox->controller.num_chans = mbox->channel_count;
+	mbox->controller.fw_xlate = mpxy_mbox_fw_xlate;
+	mbox->controller.chans = devm_kcalloc(dev, mbox->channel_count,
+					      sizeof(*mbox->controller.chans),
+					      GFP_KERNEL);
+	if (!mbox->controller.chans)
+		return -ENOMEM;
+	for (i = 0; i < mbox->channel_count; i++)
+		mbox->controller.chans[i].con_priv = &mbox->channels[i];
+
+	/* Setup MSIs for mailbox (if required) */
+	if (mbox->msi_count) {
+		/*
+		 * The device MSI domain for platform devices on RISC-V architecture
+		 * is only available after the MSI controller driver is probed so,
+		 * explicitly configure here.
+		 */
+		if (!dev_get_msi_domain(dev)) {
+			struct fwnode_handle *fwnode = dev_fwnode(dev);
+
+			/*
+			 * The device MSI domain for OF devices is only set at the
+			 * time of populating/creating OF device. If the device MSI
+			 * domain is discovered later after the OF device is created
+			 * then we need to set it explicitly before using any platform
+			 * MSI functions.
+			 */
+			if (is_of_node(fwnode)) {
+				of_msi_configure(dev, dev_of_node(dev));
+			} else if (is_acpi_device_node(fwnode)) {
+				struct irq_domain *msi_domain;
+
+				msi_domain = irq_find_matching_fwnode(imsic_acpi_get_fwnode(dev),
+								      DOMAIN_BUS_PLATFORM_MSI);
+				dev_set_msi_domain(dev, msi_domain);
+			}
+
+			if (!dev_get_msi_domain(dev))
+				return -EPROBE_DEFER;
+		}
+
+		mbox->msi_index_to_channel = devm_kcalloc(dev, mbox->msi_count,
+							  sizeof(*mbox->msi_index_to_channel),
+							  GFP_KERNEL);
+		if (!mbox->msi_index_to_channel)
+			return -ENOMEM;
+
+		for (msi_idx = 0; msi_idx < mbox->msi_count; msi_idx++) {
+			for (i = 0; i < mbox->channel_count; i++) {
+				mchan = &mbox->channels[i];
+				if (mchan->msi_index == msi_idx) {
+					mbox->msi_index_to_channel[msi_idx] = mchan;
+					break;
+				}
+			}
+		}
+
+		rc = platform_device_msi_init_and_alloc_irqs(dev, mbox->msi_count,
+							     mpxy_mbox_msi_write);
+		if (rc) {
+			return dev_err_probe(dev, rc, "Failed to allocate %d MSIs\n",
+					     mbox->msi_count);
+		}
+
+		for (i = 0; i < mbox->channel_count; i++) {
+			mchan = &mbox->channels[i];
+			if (mchan->msi_index == U32_MAX)
+				continue;
+			mchan->msi_irq = msi_get_virq(dev, mchan->msi_index);
+		}
+	}
+
+	/* Register mailbox controller */
+	rc = devm_mbox_controller_register(dev, &mbox->controller);
+	if (rc) {
+		dev_err_probe(dev, rc, "Registering SBI MPXY mailbox failed\n");
+		if (mbox->msi_count)
+			platform_device_msi_free_irqs_all(dev);
+		return rc;
+	}
+
+#ifdef CONFIG_ACPI
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (adev)
+		acpi_dev_clear_dependencies(adev);
+#endif
+
+	dev_info(dev, "mailbox registered with %d channels\n",
+		 mbox->channel_count);
+	return 0;
+}
+
+static void mpxy_mbox_remove(struct platform_device *pdev)
+{
+	struct mpxy_mbox *mbox = platform_get_drvdata(pdev);
+
+	if (mbox->msi_count)
+		platform_device_msi_free_irqs_all(mbox->dev);
+}
+
+static const struct of_device_id mpxy_mbox_of_match[] = {
+	{ .compatible = "riscv,sbi-mpxy-mbox" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, mpxy_mbox_of_match);
+
+static const struct acpi_device_id mpxy_mbox_acpi_match[] = {
+	{ "RSCV0005" },
+	{}
+};
+MODULE_DEVICE_TABLE(acpi, mpxy_mbox_acpi_match);
+
+static struct platform_driver mpxy_mbox_driver = {
+	.driver = {
+		.name = "riscv-sbi-mpxy-mbox",
+		.of_match_table = mpxy_mbox_of_match,
+		.acpi_match_table = mpxy_mbox_acpi_match,
+	},
+	.probe = mpxy_mbox_probe,
+	.remove = mpxy_mbox_remove,
+};
+module_platform_driver(mpxy_mbox_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Anup Patel <[e-mail]>");
+MODULE_DESCRIPTION("RISC-V SBI MPXY mailbox controller driver");

include/linux/byteorder/generic.h

···
 	}
 }
 
+static inline void memcpy_from_le32(u32 *dst, const __le32 *src, size_t words)
+{
+	size_t i;
+
+	for (i = 0; i < words; i++)
+		dst[i] = le32_to_cpu(src[i]);
+}
+
+static inline void memcpy_to_le32(__le32 *dst, const u32 *src, size_t words)
+{
+	size_t i;
+
+	for (i = 0; i < words; i++)
+		dst[i] = cpu_to_le32(src[i]);
+}
+
 static inline void be16_add_cpu(__be16 *var, u16 val)
 {
 	*var = cpu_to_be16(be16_to_cpu(*var) + val);

include/linux/mailbox/riscv-rpmi-message.h

···
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2025 Ventana Micro Systems Inc. */
+
+#ifndef _LINUX_RISCV_RPMI_MESSAGE_H_
+#define _LINUX_RISCV_RPMI_MESSAGE_H_
+
+#include <linux/errno.h>
+#include <linux/mailbox_client.h>
+#include <linux/types.h>
+#include <linux/wordpart.h>
+
+/* RPMI version encode/decode macros */
+#define RPMI_VER_MAJOR(__ver)		upper_16_bits(__ver)
+#define RPMI_VER_MINOR(__ver)		lower_16_bits(__ver)
+#define RPMI_MKVER(__maj, __min)	(((u32)(__maj) << 16) | (u16)(__min))
+
+/* RPMI message header */
+struct rpmi_message_header {
+	__le16 servicegroup_id;
+	u8 service_id;
+	u8 flags;
+	__le16 datalen;
+	__le16 token;
+};
+
+/* RPMI message */
+struct rpmi_message {
+	struct rpmi_message_header header;
+	u8 data[];
+};
+
+/* RPMI notification event */
+struct rpmi_notification_event {
+	__le16 event_datalen;
+	u8 event_id;
+	u8 reserved;
+	u8 event_data[];
+};
+
+/* RPMI error codes */
+enum rpmi_error_codes {
+	RPMI_SUCCESS			= 0,
+	RPMI_ERR_FAILED			= -1,
+	RPMI_ERR_NOTSUPP		= -2,
+	RPMI_ERR_INVALID_PARAM		= -3,
+	RPMI_ERR_DENIED			= -4,
+	RPMI_ERR_INVALID_ADDR		= -5,
+	RPMI_ERR_ALREADY		= -6,
+	RPMI_ERR_EXTENSION		= -7,
+	RPMI_ERR_HW_FAULT		= -8,
+	RPMI_ERR_BUSY			= -9,
+	RPMI_ERR_INVALID_STATE		= -10,
+	RPMI_ERR_BAD_RANGE		= -11,
+	RPMI_ERR_TIMEOUT		= -12,
+	RPMI_ERR_IO			= -13,
+	RPMI_ERR_NO_DATA		= -14,
+	RPMI_ERR_RESERVED_START		= -15,
+	RPMI_ERR_RESERVED_END		= -127,
+	RPMI_ERR_VENDOR_START		= -128,
+};
+
+static inline int rpmi_to_linux_error(int rpmi_error)
+{
+	switch (rpmi_error) {
+	case RPMI_SUCCESS:
+		return 0;
+	case RPMI_ERR_INVALID_PARAM:
+	case RPMI_ERR_BAD_RANGE:
+	case RPMI_ERR_INVALID_STATE:
+		return -EINVAL;
+	case RPMI_ERR_DENIED:
+		return -EPERM;
+	case RPMI_ERR_INVALID_ADDR:
+	case RPMI_ERR_HW_FAULT:
+		return -EFAULT;
+	case RPMI_ERR_ALREADY:
+		return -EALREADY;
+	case RPMI_ERR_BUSY:
+		return -EBUSY;
+	case RPMI_ERR_TIMEOUT:
+		return -ETIMEDOUT;
+	case RPMI_ERR_IO:
+		return -ECOMM;
+	case RPMI_ERR_FAILED:
+	case RPMI_ERR_NOTSUPP:
+	case RPMI_ERR_NO_DATA:
+	case RPMI_ERR_EXTENSION:
+	default:
+		return -EOPNOTSUPP;
+	}
+}
+
+/* RPMI service group IDs */
+#define RPMI_SRVGRP_SYSTEM_MSI		0x00002
+#define RPMI_SRVGRP_CLOCK		0x00008
+
+/* RPMI clock service IDs */
+enum rpmi_clock_service_id {
+	RPMI_CLK_SRV_ENABLE_NOTIFICATION = 0x01,
+	RPMI_CLK_SRV_GET_NUM_CLOCKS = 0x02,
+	RPMI_CLK_SRV_GET_ATTRIBUTES = 0x03,
+	RPMI_CLK_SRV_GET_SUPPORTED_RATES = 0x04,
+	RPMI_CLK_SRV_SET_CONFIG = 0x05,
+	RPMI_CLK_SRV_GET_CONFIG = 0x06,
+	RPMI_CLK_SRV_SET_RATE = 0x07,
+	RPMI_CLK_SRV_GET_RATE = 0x08,
+	RPMI_CLK_SRV_ID_MAX_COUNT
+};
+
+/* RPMI system MSI service IDs */
+enum rpmi_sysmsi_service_id {
+	RPMI_SYSMSI_SRV_ENABLE_NOTIFICATION = 0x01,
+	RPMI_SYSMSI_SRV_GET_ATTRIBUTES = 0x02,
+	RPMI_SYSMSI_SRV_GET_MSI_ATTRIBUTES = 0x03,
+	RPMI_SYSMSI_SRV_SET_MSI_STATE = 0x04,
+	RPMI_SYSMSI_SRV_GET_MSI_STATE = 0x05,
+	RPMI_SYSMSI_SRV_SET_MSI_TARGET = 0x06,
+	RPMI_SYSMSI_SRV_GET_MSI_TARGET = 0x07,
+	RPMI_SYSMSI_SRV_ID_MAX_COUNT
+};
+
+/* RPMI Linux mailbox attribute IDs */
+enum rpmi_mbox_attribute_id {
+	RPMI_MBOX_ATTR_SPEC_VERSION,
+	RPMI_MBOX_ATTR_MAX_MSG_DATA_SIZE,
+	RPMI_MBOX_ATTR_SERVICEGROUP_ID,
+	RPMI_MBOX_ATTR_SERVICEGROUP_VERSION,
+	RPMI_MBOX_ATTR_IMPL_ID,
+	RPMI_MBOX_ATTR_IMPL_VERSION,
+	RPMI_MBOX_ATTR_MAX_ID
+};
+
+/* RPMI Linux mailbox message types */
+enum rpmi_mbox_message_type {
+	RPMI_MBOX_MSG_TYPE_GET_ATTRIBUTE,
+	RPMI_MBOX_MSG_TYPE_SET_ATTRIBUTE,
+	RPMI_MBOX_MSG_TYPE_SEND_WITH_RESPONSE,
+	RPMI_MBOX_MSG_TYPE_SEND_WITHOUT_RESPONSE,
+	RPMI_MBOX_MSG_TYPE_NOTIFICATION_EVENT,
+	RPMI_MBOX_MSG_MAX_TYPE
+};
+
+/* RPMI Linux mailbox message instance */
+struct rpmi_mbox_message {
+	enum rpmi_mbox_message_type type;
+	union {
+		struct {
+			enum rpmi_mbox_attribute_id id;
+			u32 value;
+		} attr;
+
+		struct {
+			u32 service_id;
+			void *request;
+			unsigned long request_len;
+			void *response;
+			unsigned long max_response_len;
+			unsigned long out_response_len;
+		} data;
+
+		struct {
+			u16 event_datalen;
+			u8 event_id;
+			u8 *event_data;
+		} notif;
+	};
+	int error;
+};
+
+/* RPMI Linux mailbox message helper routines */
+static inline void rpmi_mbox_init_get_attribute(struct rpmi_mbox_message *msg,
+						enum rpmi_mbox_attribute_id id)
+{
+	msg->type = RPMI_MBOX_MSG_TYPE_GET_ATTRIBUTE;
+	msg->attr.id = id;
+	msg->attr.value = 0;
+	msg->error = 0;
+}
+
+static inline void rpmi_mbox_init_set_attribute(struct rpmi_mbox_message *msg,
+						enum rpmi_mbox_attribute_id id,
+						u32 value)
+{
+	msg->type = RPMI_MBOX_MSG_TYPE_SET_ATTRIBUTE;
+	msg->attr.id = id;
+	msg->attr.value = value;
+	msg->error = 0;
+}
+
+static inline void rpmi_mbox_init_send_with_response(struct rpmi_mbox_message *msg,
+						     u32 service_id,
+						     void *request,
+						     unsigned long request_len,
+						     void *response,
+						     unsigned long max_response_len)
+{
+	msg->type = RPMI_MBOX_MSG_TYPE_SEND_WITH_RESPONSE;
+	msg->data.service_id = service_id;
+	msg->data.request = request;
+	msg->data.request_len = request_len;
+	msg->data.response = response;
+	msg->data.max_response_len = max_response_len;
+	msg->data.out_response_len = 0;
+	msg->error = 0;
+}
+
+static inline void rpmi_mbox_init_send_without_response(struct rpmi_mbox_message *msg,
+							u32 service_id,
+							void *request,
+							unsigned long request_len)
+{
+	msg->type = RPMI_MBOX_MSG_TYPE_SEND_WITHOUT_RESPONSE;
+	msg->data.service_id = service_id;
+	msg->data.request = request;
+	msg->data.request_len = request_len;
+	msg->data.response = NULL;
+	msg->data.max_response_len = 0;
+	msg->data.out_response_len = 0;
+	msg->error = 0;
+}
+
+static inline void *rpmi_mbox_get_msg_response(struct rpmi_mbox_message *msg)
+{
+	return msg ? msg->data.response : NULL;
+}
+
+static inline int rpmi_mbox_send_message(struct mbox_chan *chan,
+					 struct rpmi_mbox_message *msg)
+{
+	int ret;
+
+	/* Send message for the underlying mailbox channel */
+	ret = mbox_send_message(chan, msg);
+	if (ret < 0)
+		return ret;
+
+	/* Explicitly signal txdone for mailbox channel */
+	ret = msg->error;
+	mbox_client_txdone(chan, ret);
+	return ret;
+}
+
+#endif /* _LINUX_RISCV_RPMI_MESSAGE_H_ */

include/linux/mailbox_controller.h

···
  *			no interrupt rises. Ignored if 'txdone_irq' is set.
  * @txpoll_period:	If 'txdone_poll' is in effect, the API polls for
  *			last TX's status after these many millisecs
+ * @fw_xlate:		Controller driver specific mapping of channel via fwnode
  * @of_xlate:		Controller driver specific mapping of channel via DT
  * @poll_hrt:		API private. hrtimer used to poll for TXDONE on all
  *			channels.
···
 	bool txdone_irq;
 	bool txdone_poll;
 	unsigned txpoll_period;
+	struct mbox_chan *(*fw_xlate)(struct mbox_controller *mbox,
+				      const struct fwnode_reference_args *sp);
 	struct mbox_chan *(*of_xlate)(struct mbox_controller *mbox,
 				      const struct of_phandle_args *sp);
 	/* Internal to API */