drm/amdgpu: enable AGP aperture on gmc10.x (v2)

Just a small optimization for accessing system pages directly.
Was missed for gmc v10 since the feature landed for older gmcs
while we were still on the emulator or gmc10 and we use the AGP
aperture for zfb on the emulator.

v2: fix up the system aperture as well
Reviewed-and-tested-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/gfxhub_v2_0.c

@@ -153,16 +153,16 @@ static void gfxhub_v2_0_init_system_aperture_regs(struct amdgpu_device *adev)
 	uint64_t value;
 
 	if (!amdgpu_sriov_vf(adev)) {
-		/* Disable AGP. */
+		/* Program the AGP BAR */
 		WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BASE, 0);
-		WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_TOP, 0);
-		WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BOT, 0x00FFFFFF);
+		WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+		WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
 
 		/* Program the system aperture low logical page number. */
 		WREG32_SOC15(GC, 0, mmGCMC_VM_SYSTEM_APERTURE_LOW_ADDR,
-			     adev->gmc.vram_start >> 18);
+			     min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);
 		WREG32_SOC15(GC, 0, mmGCMC_VM_SYSTEM_APERTURE_HIGH_ADDR,
-			     adev->gmc.vram_end >> 18);
+			     max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18);
 
 		/* Set default page address. */
 		value = adev->vram_scratch.gpu_addr - adev->gmc.vram_start

drivers/gpu/drm/amd/amdgpu/gfxhub_v2_1.c

@@ -152,16 +152,16 @@ static void gfxhub_v2_1_init_system_aperture_regs(struct amdgpu_device *adev)
 {
 	uint64_t value;
 
-	/* Disable AGP. */
+	/* Program the AGP BAR */
 	WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BASE, 0);
-	WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_TOP, 0);
-	WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BOT, 0x00FFFFFF);
+	WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+	WREG32_SOC15(GC, 0, mmGCMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
 
 	/* Program the system aperture low logical page number. */
 	WREG32_SOC15(GC, 0, mmGCMC_VM_SYSTEM_APERTURE_LOW_ADDR,
-		     adev->gmc.vram_start >> 18);
+		     min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);
 	WREG32_SOC15(GC, 0, mmGCMC_VM_SYSTEM_APERTURE_HIGH_ADDR,
-		     adev->gmc.vram_end >> 18);
+		     max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18);
 
 	/* Set default page address. */
 	value = adev->vram_scratch.gpu_addr - adev->gmc.vram_start

drivers/gpu/drm/amd/amdgpu/gmc_v10_0.c

@@ -738,6 +738,7 @@ static void gmc_v10_0_vram_gtt_location(struct amdgpu_device *adev,
 
 	amdgpu_gmc_vram_location(adev, &adev->gmc, base);
 	amdgpu_gmc_gart_location(adev, mc);
+	amdgpu_gmc_agp_location(adev, mc);
 
 	/* base offset of vram pages */
 	adev->vm_manager.vram_base_offset = adev->gfxhub.funcs->get_mc_fb_offset(adev);

drivers/gpu/drm/amd/amdgpu/mmhub_v2_0.c

@@ -195,17 +195,17 @@ static void mmhub_v2_0_init_system_aperture_regs(struct amdgpu_device *adev)
 	uint64_t value;
 	uint32_t tmp;
 
-	/* Disable AGP. */
+	/* Program the AGP BAR */
 	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BASE, 0);
-	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_TOP, 0);
-	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BOT, 0x00FFFFFF);
+	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
 
 	if (!amdgpu_sriov_vf(adev)) {
 		/* Program the system aperture low logical page number. */
 		WREG32_SOC15(MMHUB, 0, mmMMMC_VM_SYSTEM_APERTURE_LOW_ADDR,
-			     adev->gmc.vram_start >> 18);
+			     min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);
 		WREG32_SOC15(MMHUB, 0, mmMMMC_VM_SYSTEM_APERTURE_HIGH_ADDR,
-			     adev->gmc.vram_end >> 18);
+			     max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18);
 	}
 
 	/* Set default page address. */

drivers/gpu/drm/amd/amdgpu/mmhub_v2_3.c

@@ -152,14 +152,14 @@ static void mmhub_v2_3_init_system_aperture_regs(struct amdgpu_device *adev)
 
 	/* Disable AGP. */
 	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BASE, 0);
-	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_TOP, 0);
-	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BOT, 0x00FFFFFF);
+	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_BOT, adev->gmc.agp_start >> 24);
+	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_AGP_TOP, adev->gmc.agp_end >> 24);
 
 	/* Program the system aperture low logical page number. */
 	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_SYSTEM_APERTURE_LOW_ADDR,
-		     adev->gmc.vram_start >> 18);
+		     min(adev->gmc.fb_start, adev->gmc.agp_start) >> 18);
 	WREG32_SOC15(MMHUB, 0, mmMMMC_VM_SYSTEM_APERTURE_HIGH_ADDR,
-		     adev->gmc.vram_end >> 18);
+		     max(adev->gmc.fb_end, adev->gmc.agp_end) >> 18);
 
 	/* Set default page address. */
 	value = adev->vram_scratch.gpu_addr - adev->gmc.vram_start +