drm/radeon: add new callback for info ioctl register accessor

This adds a callback for each asic family to determine what
registers are allowed to be read back via the info ioctl.

The idea here is to allow usermode to query things like GPU status
registers or GPU harvest registers for profiling and determining
the gfx config.

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

drivers/gpu/drm/radeon/radeon.h

@@ -1856,6 +1856,8 @@ struct radeon_asic {
 	u32 (*get_xclk)(struct radeon_device *rdev);
 	/* get the gpu clock counter */
 	uint64_t (*get_gpu_clock_counter)(struct radeon_device *rdev);
+	/* get register for info ioctl */
+	int (*get_allowed_info_register)(struct radeon_device *rdev, u32 reg, u32 *val);
 	/* gart */
 	struct {
 		void (*tlb_flush)(struct radeon_device *rdev);
@@ -2933,6 +2935,7 @@ static inline void radeon_ring_write(struct radeon_ring *ring, uint32_t v)
 #define radeon_mc_wait_for_idle(rdev) (rdev)->asic->mc_wait_for_idle((rdev))
 #define radeon_get_xclk(rdev) (rdev)->asic->get_xclk((rdev))
 #define radeon_get_gpu_clock_counter(rdev) (rdev)->asic->get_gpu_clock_counter((rdev))
+#define radeon_get_allowed_info_register(rdev, r, v) (rdev)->asic->get_allowed_info_register((rdev), (r), (v))
 #define radeon_dpm_init(rdev) rdev->asic->dpm.init((rdev))
 #define radeon_dpm_setup_asic(rdev) rdev->asic->dpm.setup_asic((rdev))
 #define radeon_dpm_enable(rdev) rdev->asic->dpm.enable((rdev))