Merge tag 'scpi-updates-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into next/drivers

SCPI updates and fixes for v4.8

1. Adds support for device power state management using generic power
domains and runtime PM

2. Other minor/miscellaneous fixes to the driver

* tag 'scpi-updates-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
firmware: scpi: add device power domain support using genpd
Documentation: add DT bindings for ARM SCPI power domains
firmware: arm_scpi: add support for device power state management
firmware: arm_scpi: make it depend on MAILBOX instead of ARM_MHU
firmware: arm_scpi: mark scpi_get_sensor_value as static
firmware: arm_scpi: remove dvfs_get packed structure

Signed-off-by: Olof Johansson <[e-mail]>

Documentation/devicetree/bindings/arm/arm,scpi.txt

···
 			 implementation for the IDs to use. For Juno
 			 R0 and Juno R1 refer to [3].
 
+Power domain bindings for the power domains based on SCPI Message Protocol
+------------------------------------------------------------
+
+This binding uses the generic power domain binding[4].
+
+PM domain providers
+===================
+
+Required properties:
+ - #power-domain-cells : Should be 1. Contains the device or the power
+			 domain ID value used by SCPI commands.
+ - num-domains: Total number of power domains provided by SCPI. This is
+		needed as the SCPI message protocol lacks a mechanism to
+		query this information at runtime.
+
+PM domain consumers
+===================
+
+Required properties:
+ - power-domains : A phandle and PM domain specifier as defined by bindings of
+                   the power controller specified by phandle.
+
 [0] http://infocenter.arm.com/help/topic/com.arm.doc.dui0922b/index.html
 [1] Documentation/devicetree/bindings/clock/clock-bindings.txt
 [2] Documentation/devicetree/bindings/thermal/thermal.txt
 [3] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0922b/apas03s22.html
+[4] Documentation/devicetree/bindings/power/power_domain.txt
 
 Example:
 
···
 		compatible = "arm,scpi-sensors";
 		#thermal-sensor-cells = <1>;
 	};
+
+	scpi_devpd: scpi-power-domains {
+		compatible = "arm,scpi-power-domains";
+		num-domains = <2>;
+		#power-domain-cells = <1>;
+	};
 };
 
 cpu@0 {
···
 	...
 	reg = <0 0x7ff60000 0 0x1000>;
 	clocks = <&scpi_clk 4>;
+	power-domains = <&scpi_devpd 1>;
 };
 
 thermal-zones {
···
 temperature sensor provided by SCP firmware to setup a thermal
 zone. The ID "3" is the sensor identifier for the temperature sensor
 as used by the firmware.
+
+The num-domains property in scpi-power-domains domain specifies that
+SCPI provides 2 power domains. The hdlcd node uses the power domain with
+domain ID 1.

drivers/firmware/Kconfig

···
 
 config ARM_SCPI_PROTOCOL
 	tristate "ARM System Control and Power Interface (SCPI) Message Protocol"
-	depends on ARM_MHU
+	depends on MAILBOX
 	help
 	  System Control and Power Interface (SCPI) Message Protocol is
 	  defined for the purpose of communication between the Application
···
 
 	  This protocol library provides interface for all the client drivers
 	  making use of the features offered by the SCP.
+
+config ARM_SCPI_POWER_DOMAIN
+	tristate "SCPI power domain driver"
+	depends on ARM_SCPI_PROTOCOL || COMPILE_TEST
+	default y
+	select PM_GENERIC_DOMAINS if PM
+	select PM_GENERIC_DOMAINS_OF if PM
+	help
+	  This enables support for the SCPI power domains which can be
+	  enabled or disabled via the SCP firmware
 
 config EDD
 	tristate "BIOS Enhanced Disk Drive calls determine boot disk"

drivers/firmware/Makefile

···
 #
 obj-$(CONFIG_ARM_PSCI_FW)	+= psci.o
 obj-$(CONFIG_ARM_SCPI_PROTOCOL)	+= arm_scpi.o
+obj-$(CONFIG_ARM_SCPI_POWER_DOMAIN) += scpi_pm_domain.o
 obj-$(CONFIG_DMI)		+= dmi_scan.o
 obj-$(CONFIG_DMI_SYSFS)		+= dmi-sysfs.o
 obj-$(CONFIG_EDD)		+= edd.o

drivers/firmware/arm_scpi.c

···
 	} opps[MAX_DVFS_OPPS];
 } __packed;
 
-struct dvfs_get {
-	u8 index;
-} __packed;
-
 struct dvfs_set {
 	u8 domain;
 	u8 index;
···
 struct sensor_value {
 	__le32 lo_val;
 	__le32 hi_val;
+} __packed;
+
+struct dev_pstate_set {
+	u16 dev_id;
+	u8 pstate;
 } __packed;
 
 static struct scpi_drvinfo *scpi_info;
···
 static int scpi_dvfs_get_idx(u8 domain)
 {
 	int ret;
-	struct dvfs_get dvfs;
+	u8 dvfs_idx;
 
 	ret = scpi_send_message(SCPI_CMD_GET_DVFS, &domain, sizeof(domain),
-				&dvfs, sizeof(dvfs));
-	return ret ? ret : dvfs.index;
+				&dvfs_idx, sizeof(dvfs_idx));
+	return ret ? ret : dvfs_idx;
 }
 
 static int scpi_dvfs_set_idx(u8 domain, u8 index)
···
 	return ret;
 }
 
-int scpi_sensor_get_value(u16 sensor, u64 *val)
+static int scpi_sensor_get_value(u16 sensor, u64 *val)
 {
 	__le16 id = cpu_to_le16(sensor);
 	struct sensor_value buf;
···
 	return ret;
 }
 
+static int scpi_device_get_power_state(u16 dev_id)
+{
+	int ret;
+	u8 pstate;
+	__le16 id = cpu_to_le16(dev_id);
+
+	ret = scpi_send_message(SCPI_CMD_GET_DEVICE_PWR_STATE, &id,
+				sizeof(id), &pstate, sizeof(pstate));
+	return ret ? ret : pstate;
+}
+
+static int scpi_device_set_power_state(u16 dev_id, u8 pstate)
+{
+	int stat;
+	struct dev_pstate_set dev_set = {
+		.dev_id = cpu_to_le16(dev_id),
+		.pstate = pstate,
+	};
+
+	return scpi_send_message(SCPI_CMD_SET_DEVICE_PWR_STATE, &dev_set,
+				 sizeof(dev_set), &stat, sizeof(stat));
+}
+
 static struct scpi_ops scpi_ops = {
 	.get_version = scpi_get_version,
 	.clk_get_range = scpi_clk_get_range,
···
 	.sensor_get_capability = scpi_sensor_get_capability,
 	.sensor_get_info = scpi_sensor_get_info,
 	.sensor_get_value = scpi_sensor_get_value,
+	.device_get_power_state = scpi_device_get_power_state,
+	.device_set_power_state = scpi_device_set_power_state,
 };
 
 struct scpi_ops *get_scpi_ops(void)

drivers/firmware/scpi_pm_domain.c

···
+/*
+ * SCPI Generic power domain support.
+ *
+ * Copyright (C) 2016 ARM Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/of_platform.h>
+#include <linux/pm_domain.h>
+#include <linux/scpi_protocol.h>
+
+struct scpi_pm_domain {
+	struct generic_pm_domain genpd;
+	struct scpi_ops *ops;
+	u32 domain;
+	char name[30];
+};
+
+/*
+ * These device power state values are not well-defined in the specification.
+ * In case, different implementations use different values, we can make these
+ * specific to compatibles rather than getting these values from device tree.
+ */
+enum scpi_power_domain_state {
+	SCPI_PD_STATE_ON = 0,
+	SCPI_PD_STATE_OFF = 3,
+};
+
+#define to_scpi_pd(gpd) container_of(gpd, struct scpi_pm_domain, genpd)
+
+static int scpi_pd_power(struct scpi_pm_domain *pd, bool power_on)
+{
+	int ret;
+	enum scpi_power_domain_state state;
+
+	if (power_on)
+		state = SCPI_PD_STATE_ON;
+	else
+		state = SCPI_PD_STATE_OFF;
+
+	ret = pd->ops->device_set_power_state(pd->domain, state);
+	if (ret)
+		return ret;
+
+	return !(state == pd->ops->device_get_power_state(pd->domain));
+}
+
+static int scpi_pd_power_on(struct generic_pm_domain *domain)
+{
+	struct scpi_pm_domain *pd = to_scpi_pd(domain);
+
+	return scpi_pd_power(pd, true);
+}
+
+static int scpi_pd_power_off(struct generic_pm_domain *domain)
+{
+	struct scpi_pm_domain *pd = to_scpi_pd(domain);
+
+	return scpi_pd_power(pd, false);
+}
+
+static int scpi_pm_domain_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *np = dev->of_node;
+	struct scpi_pm_domain *scpi_pd;
+	struct genpd_onecell_data *scpi_pd_data;
+	struct generic_pm_domain **domains;
+	struct scpi_ops *scpi_ops;
+	int ret, num_domains, i;
+
+	scpi_ops = get_scpi_ops();
+	if (!scpi_ops)
+		return -EPROBE_DEFER;
+
+	if (!np) {
+		dev_err(dev, "device tree node not found\n");
+		return -ENODEV;
+	}
+
+	if (!scpi_ops->device_set_power_state ||
+	    !scpi_ops->device_get_power_state) {
+		dev_err(dev, "power domains not supported in the firmware\n");
+		return -ENODEV;
+	}
+
+	ret = of_property_read_u32(np, "num-domains", &num_domains);
+	if (ret) {
+		dev_err(dev, "number of domains not found\n");
+		return -EINVAL;
+	}
+
+	scpi_pd = devm_kcalloc(dev, num_domains, sizeof(*scpi_pd), GFP_KERNEL);
+	if (!scpi_pd)
+		return -ENOMEM;
+
+	scpi_pd_data = devm_kzalloc(dev, sizeof(*scpi_pd_data), GFP_KERNEL);
+	if (!scpi_pd_data)
+		return -ENOMEM;
+
+	domains = devm_kcalloc(dev, num_domains, sizeof(*domains), GFP_KERNEL);
+	if (!domains)
+		return -ENOMEM;
+
+	for (i = 0; i < num_domains; i++, scpi_pd++) {
+		domains[i] = &scpi_pd->genpd;
+
+		scpi_pd->domain = i;
+		scpi_pd->ops = scpi_ops;
+		sprintf(scpi_pd->name, "%s.%d", np->name, i);
+		scpi_pd->genpd.name = scpi_pd->name;
+		scpi_pd->genpd.power_off = scpi_pd_power_off;
+		scpi_pd->genpd.power_on = scpi_pd_power_on;
+
+		/*
+		 * Treat all power domains as off at boot.
+		 *
+		 * The SCP firmware itself may have switched on some domains,
+		 * but for reference counting purpose, keep it this way.
+		 */
+		pm_genpd_init(&scpi_pd->genpd, NULL, true);
+	}
+
+	scpi_pd_data->domains = domains;
+	scpi_pd_data->num_domains = num_domains;
+
+	of_genpd_add_provider_onecell(np, scpi_pd_data);
+
+	return 0;
+}
+
+static const struct of_device_id scpi_power_domain_ids[] = {
+	{ .compatible = "arm,scpi-power-domains", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, scpi_power_domain_ids);
+
+static struct platform_driver scpi_power_domain_driver = {
+	.driver	= {
+		.name = "scpi_power_domain",
+		.of_match_table = scpi_power_domain_ids,
+	},
+	.probe = scpi_pm_domain_probe,
+};
+module_platform_driver(scpi_power_domain_driver);
+
+MODULE_AUTHOR("Sudeep Holla <[e-mail]>");
+MODULE_DESCRIPTION("ARM SCPI power domain driver");
+MODULE_LICENSE("GPL v2");

include/linux/scpi_protocol.h

···
 	int (*sensor_get_capability)(u16 *sensors);
 	int (*sensor_get_info)(u16 sensor_id, struct scpi_sensor_info *);
 	int (*sensor_get_value)(u16, u64 *);
+	int (*device_get_power_state)(u16);
+	int (*device_set_power_state)(u16, u8);
 };
 
 #if IS_REACHABLE(CONFIG_ARM_SCPI_PROTOCOL)