drm/radeon: don't touch DCE or VGA regs on Hainan (v3)

Hainan has no display hardware:
- no DCE (crtc, uniphy, dac, etc.)
- no VGA

v2: fix bios fetch
v3: fix interrupts

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index 06c261b..8f9e2d3 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -2343,11 +2343,13 @@
 	u32 crtc_enabled, tmp, frame_count, blackout;
 	int i, j;
 
-	save->vga_render_control = RREG32(VGA_RENDER_CONTROL);
-	save->vga_hdp_control = RREG32(VGA_HDP_CONTROL);
+	if (!ASIC_IS_NODCE(rdev)) {
+		save->vga_render_control = RREG32(VGA_RENDER_CONTROL);
+		save->vga_hdp_control = RREG32(VGA_HDP_CONTROL);
 
-	/* disable VGA render */
-	WREG32(VGA_RENDER_CONTROL, 0);
+		/* disable VGA render */
+		WREG32(VGA_RENDER_CONTROL, 0);
+	}
 	/* blank the display controllers */
 	for (i = 0; i < rdev->num_crtc; i++) {
 		crtc_enabled = RREG32(EVERGREEN_CRTC_CONTROL + crtc_offsets[i]) & EVERGREEN_CRTC_MASTER_EN;
@@ -2438,8 +2440,11 @@
 		WREG32(EVERGREEN_GRPH_SECONDARY_SURFACE_ADDRESS + crtc_offsets[i],
 		       (u32)rdev->mc.vram_start);
 	}
-	WREG32(EVERGREEN_VGA_MEMORY_BASE_ADDRESS_HIGH, upper_32_bits(rdev->mc.vram_start));
-	WREG32(EVERGREEN_VGA_MEMORY_BASE_ADDRESS, (u32)rdev->mc.vram_start);
+
+	if (!ASIC_IS_NODCE(rdev)) {
+		WREG32(EVERGREEN_VGA_MEMORY_BASE_ADDRESS_HIGH, upper_32_bits(rdev->mc.vram_start));
+		WREG32(EVERGREEN_VGA_MEMORY_BASE_ADDRESS, (u32)rdev->mc.vram_start);
+	}
 
 	/* unlock regs and wait for update */
 	for (i = 0; i < rdev->num_crtc; i++) {
@@ -2499,10 +2504,12 @@
 			}
 		}
 	}
-	/* Unlock vga access */
-	WREG32(VGA_HDP_CONTROL, save->vga_hdp_control);
-	mdelay(1);
-	WREG32(VGA_RENDER_CONTROL, save->vga_render_control);
+	if (!ASIC_IS_NODCE(rdev)) {
+		/* Unlock vga access */
+		WREG32(VGA_HDP_CONTROL, save->vga_hdp_control);
+		mdelay(1);
+		WREG32(VGA_RENDER_CONTROL, save->vga_render_control);
+	}
 }
 
 void evergreen_mc_program(struct radeon_device *rdev)