drm/radeon: add pci config hard reset

This is used to hard reset the asic.  If a soft
reset is not able to reset things, a hard reset
can be used.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon.h

@@ -140,6 +140,9 @@ extern int radeon_hard_reset;
 #define RADEON_VA_RESERVED_SIZE			(8 << 20)
 #define RADEON_IB_VM_MAX_SIZE			(64 << 10)
 
+/* hard reset data */
+#define RADEON_ASIC_RESET_DATA                  0x39d5e86b
+
 /* reset flags */
 #define RADEON_RESET_GFX			(1 << 0)
 #define RADEON_RESET_COMPUTE			(1 << 1)
@@ -2675,6 +2678,7 @@ void radeon_ring_write(struct radeon_ring *ring, uint32_t v);
 /* Common functions */
 /* AGP */
 extern int radeon_gpu_reset(struct radeon_device *rdev);
+extern void radeon_pci_config_reset(struct radeon_device *rdev);
 extern void r600_set_bios_scratch_engine_hung(struct radeon_device *rdev, bool hung);
 extern void radeon_agp_disable(struct radeon_device *rdev);
 extern int radeon_modeset_init(struct radeon_device *rdev);

drivers/gpu/drm/radeon/radeon_device.c

@@ -144,6 +144,11 @@ void radeon_program_register_sequence(struct radeon_device *rdev,
 	}
 }
 
+void radeon_pci_config_reset(struct radeon_device *rdev)
+{
+	pci_write_config_dword(rdev->pdev, 0x7c, RADEON_ASIC_RESET_DATA);
+}
+
 /**
  * radeon_surface_init - Clear GPU surface registers.
  *