drm/radeon: add INFO query for GPU temperature

Useful for profiling.
Tested-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_kms.c

@@ -547,6 +547,13 @@ static int radeon_info_ioctl(struct drm_device *dev, void *data, struct drm_file
 		else
 			*value = 1;
 		break;
+	case RADEON_INFO_CURRENT_GPU_TEMP:
+		/* get temperature in millidegrees C */
+		if (rdev->asic->pm.get_temperature)
+			*value = radeon_get_temperature(rdev);
+		else
+			*value = 0;
+		break;
 	default:
 		DRM_DEBUG_KMS("Invalid request %d\n", info->request);
 		return -EINVAL;

include/uapi/drm/radeon_drm.h

@@ -1034,6 +1034,7 @@ struct drm_radeon_cs {
 #define RADEON_INFO_VRAM_USAGE		0x1e
 #define RADEON_INFO_GTT_USAGE		0x1f
 #define RADEON_INFO_ACTIVE_CU_COUNT	0x20
+#define RADEON_INFO_CURRENT_GPU_TEMP	0x21
 
 struct drm_radeon_info {
 	uint32_t		request;