drm/amdgpu/gmc: set a default disable value for AGP

To disable AGP, the start needs to be set to a higher
value than the end.  Set a default disable value for
the AGP aperture and allow the IP specific GMC code
to enable it selectively be calling amdgpu_gmc_agp_location().
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -316,14 +316,6 @@ void amdgpu_gmc_agp_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
 	const uint64_t sixteen_gb_mask = ~(sixteen_gb - 1);
 	u64 size_af, size_bf;
 
-	if (amdgpu_sriov_vf(adev)) {
-		mc->agp_start = 0xffffffffffff;
-		mc->agp_end = 0x0;
-		mc->agp_size = 0;
-
-		return;
-	}
-
 	if (mc->fb_start > mc->gart_start) {
 		size_bf = (mc->fb_start & sixteen_gb_mask) -
 			ALIGN(mc->gart_end + 1, sixteen_gb);
@@ -347,6 +339,25 @@ void amdgpu_gmc_agp_location(struct amdgpu_device *adev, struct amdgpu_gmc *mc)
 			mc->agp_size >> 20, mc->agp_start, mc->agp_end);
 }
 
+/**
+ * amdgpu_gmc_set_agp_default - Set the default AGP aperture value.
+ * @adev: amdgpu device structure holding all necessary information
+ * @mc: memory controller structure holding memory information
+ *
+ * To disable the AGP aperture, you need to set the start to a larger
+ * value than the end.  This function sets the default value which
+ * can then be overridden using amdgpu_gmc_agp_location() if you want
+ * to enable the AGP aperture on a specific chip.
+ *
+ */
+void amdgpu_gmc_set_agp_default(struct amdgpu_device *adev,
+				struct amdgpu_gmc *mc)
+{
+	mc->agp_start = 0xffffffffffff;
+	mc->agp_end = 0;
+	mc->agp_size = 0;
+}
+
 /**
  * amdgpu_gmc_fault_key - get hask key from vm fault address and pasid
  *

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

@@ -394,6 +394,8 @@ void amdgpu_gmc_gart_location(struct amdgpu_device *adev,
 			      struct amdgpu_gmc *mc);
 void amdgpu_gmc_agp_location(struct amdgpu_device *adev,
 			     struct amdgpu_gmc *mc);
+void amdgpu_gmc_set_agp_default(struct amdgpu_device *adev,
+				struct amdgpu_gmc *mc);
 bool amdgpu_gmc_filter_faults(struct amdgpu_device *adev,
 			      struct amdgpu_ih_ring *ih, uint64_t addr,
 			      uint16_t pasid, uint64_t timestamp);

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

@@ -1062,6 +1062,9 @@ static const char * const amdgpu_vram_names[] = {
  */
 int amdgpu_bo_init(struct amdgpu_device *adev)
 {
+	/* set the default AGP aperture state */
+	amdgpu_gmc_set_agp_default(adev, &adev->gmc);
+
 	/* On A+A platform, VRAM can be mapped as WB */
 	if (!adev->gmc.xgmi.connected_to_cpu && !adev->gmc.is_app_apu) {
 		/* reserve PAT memory space to WC for VRAM */

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

@@ -671,7 +671,8 @@ 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);
+	if (!amdgpu_sriov_vf(adev))
+		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/gmc_v11_0.c

@@ -635,7 +635,8 @@ static void gmc_v11_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);
+	if (!amdgpu_sriov_vf(adev))
+		amdgpu_gmc_agp_location(adev, mc);
 
 	/* base offset of vram pages */
 	if (amdgpu_sriov_vf(adev))

drivers/gpu/drm/amd/amdgpu/gmc_v6_0.c

@@ -253,8 +253,8 @@ static void gmc_v6_0_mc_program(struct amdgpu_device *adev)
 	WREG32(mmMC_VM_SYSTEM_APERTURE_DEFAULT_ADDR,
 	       adev->mem_scratch.gpu_addr >> 12);
 	WREG32(mmMC_VM_AGP_BASE, 0);
-	WREG32(mmMC_VM_AGP_TOP, 0);
-	WREG32(mmMC_VM_AGP_BOT, 0x0FFFFFFF);
+	WREG32(mmMC_VM_AGP_TOP, adev->gmc.agp_end >> 22);
+	WREG32(mmMC_VM_AGP_BOT, adev->gmc.agp_start >> 22);
 
 	if (gmc_v6_0_wait_for_idle((void *)adev))
 		dev_warn(adev->dev, "Wait for MC idle timedout !\n");

drivers/gpu/drm/amd/amdgpu/gmc_v7_0.c

@@ -288,8 +288,8 @@ static void gmc_v7_0_mc_program(struct amdgpu_device *adev)
 	WREG32(mmMC_VM_SYSTEM_APERTURE_DEFAULT_ADDR,
 	       adev->mem_scratch.gpu_addr >> 12);
 	WREG32(mmMC_VM_AGP_BASE, 0);
-	WREG32(mmMC_VM_AGP_TOP, 0);
-	WREG32(mmMC_VM_AGP_BOT, 0x0FFFFFFF);
+	WREG32(mmMC_VM_AGP_TOP, adev->gmc.agp_end >> 22);
+	WREG32(mmMC_VM_AGP_BOT, adev->gmc.agp_start >> 22);
 	if (gmc_v7_0_wait_for_idle((void *)adev))
 		dev_warn(adev->dev, "Wait for MC idle timedout !\n");
 

drivers/gpu/drm/amd/amdgpu/gmc_v8_0.c

@@ -473,8 +473,8 @@ static void gmc_v8_0_mc_program(struct amdgpu_device *adev)
 	}
 
 	WREG32(mmMC_VM_AGP_BASE, 0);
-	WREG32(mmMC_VM_AGP_TOP, 0);
-	WREG32(mmMC_VM_AGP_BOT, 0x0FFFFFFF);
+	WREG32(mmMC_VM_AGP_TOP, adev->gmc.agp_end >> 22);
+	WREG32(mmMC_VM_AGP_BOT, adev->gmc.agp_start >> 22);
 	if (gmc_v8_0_wait_for_idle((void *)adev))
 		dev_warn(adev->dev, "Wait for MC idle timedout !\n");
 

drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c

@@ -1612,7 +1612,8 @@ static void gmc_v9_0_vram_gtt_location(struct amdgpu_device *adev,
 	} else {
 		amdgpu_gmc_vram_location(adev, mc, base);
 		amdgpu_gmc_gart_location(adev, mc);
-		amdgpu_gmc_agp_location(adev, mc);
+		if (!amdgpu_sriov_vf(adev))
+			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/display/amdgpu_dm/amdgpu_dm.c

@@ -1256,7 +1256,7 @@ static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_
 	agp_top = adev->gmc.agp_end >> 24;
 
 	/* AGP aperture is disabled */
-	if (agp_bot == agp_top) {
+	if (agp_bot > agp_top) {
 		logical_addr_low = adev->gmc.fb_start >> 18;
 		if (adev->apu_flags & AMD_APU_IS_RAVEN2)
 			/*