drm/amdgpu: support atcs method powershift (v4)

add support to handle ATCS method for power shift control.
used to communicate dGPU device state to SBIOS.

V2: use defined acpi func for checking psc support (Lijo)
fix alignment (Shashank)
V3: rebased on unified ATCS handling (Alex)
V4: rebased on ATPX/ATCS structures global (Alex)

Signed-off-by: Sathishkumar S <[e-mail]>
Reviewed-by: Alex Deucher <[e-mail]>
Reviewed-by: Lijo Lazar <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

drivers/gpu/drm/amd/amdgpu/amdgpu.h

···
 int amdgpu_acpi_init(struct amdgpu_device *adev);
 void amdgpu_acpi_fini(struct amdgpu_device *adev);
 bool amdgpu_acpi_is_pcie_performance_request_supported(struct amdgpu_device *adev);
+bool amdgpu_acpi_is_power_shift_control_supported(void);
 int amdgpu_acpi_pcie_performance_request(struct amdgpu_device *adev,
 						u8 perf_req, bool advertise);
+int amdgpu_acpi_power_shift_control(struct amdgpu_device *adev,
+				    u8 dev_state, bool drv_state);
 int amdgpu_acpi_pcie_notify_device_ready(struct amdgpu_device *adev);
 
 void amdgpu_acpi_get_backlight_caps(struct amdgpu_dm_backlight_caps *caps);
···
 static inline void amdgpu_acpi_fini(struct amdgpu_device *adev) { }
 static inline bool amdgpu_acpi_is_s0ix_supported(struct amdgpu_device *adev) { return false; }
 static inline void amdgpu_acpi_detect(void) { }
+static inline bool amdgpu_acpi_is_power_shift_control_supported(void) { return false; }
+static inline int amdgpu_acpi_power_shift_control(struct amdgpu_device *adev,
+						  u8 dev_state, bool drv_state) { return 0; }
 #endif
 
 int amdgpu_cs_find_mapping(struct amdgpu_cs_parser *parser,

drivers/gpu/drm/amd/amdgpu/amdgpu_acpi.c

···
 	bool pcie_perf_req;
 	bool pcie_dev_rdy;
 	bool pcie_bus_width;
+	bool power_shift_control;
 };
 
 struct amdgpu_atcs {
···
 	f->pcie_perf_req = mask & ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED;
 	f->pcie_dev_rdy = mask & ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED;
 	f->pcie_bus_width = mask & ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED;
+	f->power_shift_control = mask & ATCS_SET_POWER_SHIFT_CONTROL_SUPPORTED;
 }
 
 /**
···
 		return true;
 
 	return false;
+}
+
+/**
+ * amdgpu_acpi_is_power_shift_control_supported
+ *
+ * Check if the ATCS power shift control method
+ * is supported.
+ * returns true if supported, false if not.
+ */
+bool amdgpu_acpi_is_power_shift_control_supported(void)
+{
+	return amdgpu_acpi_priv.atcs.functions.power_shift_control;
 }
 
 /**
···
 			udelay(10);
 			break;
 		}
+	}
+
+	return 0;
+}
+
+/**
+ * amdgpu_acpi_power_shift_control
+ *
+ * @adev: amdgpu_device pointer
+ * @dev_state: device acpi state
+ * @drv_state: driver state
+ *
+ * Executes the POWER_SHIFT_CONTROL method to
+ * communicate current dGPU device state and
+ * driver state to APU/SBIOS.
+ * returns 0 on success, error on failure.
+ */
+int amdgpu_acpi_power_shift_control(struct amdgpu_device *adev,
+				    u8 dev_state, bool drv_state)
+{
+	union acpi_object *info;
+	struct amdgpu_atcs *atcs = &amdgpu_acpi_priv.atcs;
+	struct atcs_pwr_shift_input atcs_input;
+	struct acpi_buffer params;
+
+	if (!amdgpu_acpi_is_power_shift_control_supported())
+		return -EINVAL;
+
+	atcs_input.size = sizeof(struct atcs_pwr_shift_input);
+	/* dGPU id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
+	atcs_input.dgpu_id = adev->pdev->devfn | (adev->pdev->bus->number << 8);
+	atcs_input.dev_acpi_state = dev_state;
+	atcs_input.drv_state = drv_state;
+
+	params.length = sizeof(struct atcs_pwr_shift_input);
+	params.pointer = &atcs_input;
+
+	info = amdgpu_atcs_call(atcs, ATCS_FUNCTION_POWER_SHIFT_CONTROL, &params);
+	if (!info) {
+		DRM_ERROR("ATCS PSC update failed\n");
+		return -EIO;
 	}
 
 	return 0;

drivers/gpu/drm/amd/include/amd_acpi.h

···
 	u8 ret_val;		/* return value */
 } __packed;
 
+struct atcs_pwr_shift_input {
+	u16 size;		/* structure size in bytes (includes size field) */
+	u16 dgpu_id;		/* client id (bit 2-0: func num, 7-3: dev num, 15-8: bus num) */
+	u8 dev_acpi_state;	/* D0 = 0, D3 hot = 3 */
+	u8 drv_state;	/* 0 = operational, 1 = not operational */
+} __packed;
+
 /* AMD hw uses four ACPI control methods:
  * 1. ATIF
  * ARG0: (ACPI_INTEGER) function code
···
 #       define ATCS_PCIE_PERFORMANCE_REQUEST_SUPPORTED             (1 << 1)
 #       define ATCS_PCIE_DEVICE_READY_NOTIFICATION_SUPPORTED       (1 << 2)
 #       define ATCS_SET_PCIE_BUS_WIDTH_SUPPORTED                   (1 << 3)
+#       define ATCS_SET_POWER_SHIFT_CONTROL_SUPPORTED		   (1 << 7)
 #define ATCS_FUNCTION_GET_EXTERNAL_STATE                           0x1
 /* ARG0: ATCS_FUNCTION_GET_EXTERNAL_STATE
  * ARG1: none
···
  * OUTPUT:
  * WORD  - structure size in bytes (includes size field)
  * BYTE  - number of active lanes
+ */
+
+#define ATCS_FUNCTION_POWER_SHIFT_CONTROL                          0x8
+/* ARG0: ATCS_FUNCTION_POWER_SHIFT_CONTROL
+ * ARG1:
+ * WORD  - structure size in bytes (includes size field)
+ * WORD  - dGPU id (bit 2-0: func num, 7-3: dev num, 15-8: bus num)
+ * BYTE  - Device ACPI state
+ * BYTE  - Driver state
+ * OUTPUT: none
  */
 
 #endif