drm/amdgpu: reduce ip discovery data reading size

Only read first 4K data instead of whole TMR block,
so we can reduce the time in full access mode.
Signed-off-by: Wenhui Sheng <Wenhui.Sheng@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -133,7 +133,7 @@ static int hw_id_map[MAX_HWIP] = {
 static int amdgpu_discovery_read_binary(struct amdgpu_device *adev, uint8_t *binary)
 {
 	uint64_t vram_size = (uint64_t)RREG32(mmRCC_CONFIG_MEMSIZE) << 20;
-	uint64_t pos = vram_size - adev->discovery_tmr_size;
+	uint64_t pos = vram_size - DISCOVERY_TMR_OFFSET;
 
 	amdgpu_device_vram_access(adev, pos, (uint32_t *)binary,
 				  adev->discovery_tmr_size, false);

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

@@ -24,7 +24,8 @@
 #ifndef __AMDGPU_DISCOVERY__
 #define __AMDGPU_DISCOVERY__
 
-#define DISCOVERY_TMR_SIZE  (64 << 10)
+#define DISCOVERY_TMR_SIZE      (4 << 10)
+#define DISCOVERY_TMR_OFFSET    (64 << 10)
 
 void amdgpu_discovery_fini(struct amdgpu_device *adev);
 int amdgpu_discovery_reg_base_init(struct amdgpu_device *adev);