drm/amdgpu: Reserve shared memory on VRAM for SR-IOV

SR-IOV need to reserve a piece of shared VRAM at the exact place
to exchange data betweem PF and VF. The start address and size of
the shared mem are passed to guest through VBIOS structure
VRAM_UsageByFirmware.

VRAM_UsageByFirmware is a general feature in VBIOS, it indicates
that VBIOS need to reserve a piece of memory on the VRAM.

Because the mem address is specified. Reserve it early in
amdgpu_ttm_init to make sure that it can monoplize the space.
Signed-off-by: Horace Chen <horace.chen@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1378,6 +1378,18 @@ struct amdgpu_atcs {
 	struct amdgpu_atcs_functions functions;
 };
 
+/*
+ * Firmware VRAM reservation
+ */
+struct amdgpu_fw_vram_usage {
+	u64 start_offset;
+	u64 size;
+	struct amdgpu_bo *reserved_bo;
+	void *va;
+};
+
+int amdgpu_fw_reserve_vram_init(struct amdgpu_device *adev);
+
 /*
  * CGS
  */
@@ -1582,6 +1594,8 @@ struct amdgpu_device {
 	struct delayed_work     late_init_work;
 
 	struct amdgpu_virt	virt;
+	/* firmware VRAM reservation */
+	struct amdgpu_fw_vram_usage fw_vram_usage;
 
 	/* link all shadow bo */
 	struct list_head                shadow_list;

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

@@ -1807,6 +1807,8 @@ int amdgpu_atombios_allocate_fb_scratch(struct amdgpu_device *adev)
 	uint16_t data_offset;
 	int usage_bytes = 0;
 	struct _ATOM_VRAM_USAGE_BY_FIRMWARE *firmware_usage;
+	u64 start_addr;
+	u64 size;
 
 	if (amdgpu_atom_parse_data_header(ctx, index, NULL, NULL, NULL, &data_offset)) {
 		firmware_usage = (struct _ATOM_VRAM_USAGE_BY_FIRMWARE *)(ctx->bios + data_offset);
@@ -1815,8 +1817,22 @@ int amdgpu_atombios_allocate_fb_scratch(struct amdgpu_device *adev)
 			  le32_to_cpu(firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware),
 			  le16_to_cpu(firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb));
 
+		start_addr = firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware;
+		size = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb;
+
+		if ((uint32_t)(start_addr & ATOM_VRAM_OPERATION_FLAGS_MASK) ==
+			(uint32_t)(ATOM_VRAM_BLOCK_SRIOV_MSG_SHARE_RESERVATION <<
+			ATOM_VRAM_OPERATION_FLAGS_SHIFT)) {
+			/* Firmware request VRAM reservation for SR-IOV */
+			adev->fw_vram_usage.start_offset = (start_addr &
+				(~ATOM_VRAM_OPERATION_FLAGS_MASK)) << 10;
+			adev->fw_vram_usage.size = size << 10;
+			/* Use the default scratch size */
+			usage_bytes = 0;
+		} else {
 			usage_bytes = le16_to_cpu(firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb) * 1024;
 		}
+	}
 	ctx->scratch_size_bytes = 0;
 	if (usage_bytes == 0)
 		usage_bytes = 20 * 1024;

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

@@ -657,6 +657,81 @@ void amdgpu_gart_location(struct amdgpu_device *adev, struct amdgpu_mc *mc)
 			mc->gart_size >> 20, mc->gart_start, mc->gart_end);
 }
 
+/*
+ * Firmware Reservation functions
+ */
+/**
+ * amdgpu_fw_reserve_vram_fini - free fw reserved vram
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * free fw reserved vram if it has been reserved.
+ */
+void amdgpu_fw_reserve_vram_fini(struct amdgpu_device *adev)
+{
+	amdgpu_bo_free_kernel(&adev->fw_vram_usage.reserved_bo,
+		NULL, &adev->fw_vram_usage.va);
+}
+
+/**
+ * amdgpu_fw_reserve_vram_init - create bo vram reservation from fw
+ *
+ * @adev: amdgpu_device pointer
+ *
+ * create bo vram reservation from fw.
+ */
+int amdgpu_fw_reserve_vram_init(struct amdgpu_device *adev)
+{
+	int r = 0;
+	u64 gpu_addr;
+	u64 vram_size = adev->mc.visible_vram_size;
+
+	adev->fw_vram_usage.va = NULL;
+	adev->fw_vram_usage.reserved_bo = NULL;
+
+	if (adev->fw_vram_usage.size > 0 &&
+		adev->fw_vram_usage.size <= vram_size) {
+
+		r = amdgpu_bo_create(adev, adev->fw_vram_usage.size,
+			PAGE_SIZE, true, 0,
+			AMDGPU_GEM_CREATE_CPU_ACCESS_REQUIRED |
+			AMDGPU_GEM_CREATE_VRAM_CONTIGUOUS, NULL, NULL, 0,
+			&adev->fw_vram_usage.reserved_bo);
+		if (r)
+			goto error_create;
+
+		r = amdgpu_bo_reserve(adev->fw_vram_usage.reserved_bo, false);
+		if (r)
+			goto error_reserve;
+		r = amdgpu_bo_pin_restricted(adev->fw_vram_usage.reserved_bo,
+			AMDGPU_GEM_DOMAIN_VRAM,
+			adev->fw_vram_usage.start_offset,
+			(adev->fw_vram_usage.start_offset +
+			adev->fw_vram_usage.size), &gpu_addr);
+		if (r)
+			goto error_pin;
+		r = amdgpu_bo_kmap(adev->fw_vram_usage.reserved_bo,
+			&adev->fw_vram_usage.va);
+		if (r)
+			goto error_kmap;
+
+		amdgpu_bo_unreserve(adev->fw_vram_usage.reserved_bo);
+	}
+	return r;
+
+error_kmap:
+	amdgpu_bo_unpin(adev->fw_vram_usage.reserved_bo);
+error_pin:
+	amdgpu_bo_unreserve(adev->fw_vram_usage.reserved_bo);
+error_reserve:
+	amdgpu_bo_unref(&adev->fw_vram_usage.reserved_bo);
+error_create:
+	adev->fw_vram_usage.va = NULL;
+	adev->fw_vram_usage.reserved_bo = NULL;
+	return r;
+}
+
+
 /*
  * GPU helpers function.
  */
@@ -2300,6 +2375,7 @@ void amdgpu_device_fini(struct amdgpu_device *adev)
 	/* evict vram memory */
 	amdgpu_bo_evict_vram(adev);
 	amdgpu_ib_pool_fini(adev);
+	amdgpu_fw_reserve_vram_fini(adev);
 	amdgpu_fence_driver_fini(adev);
 	amdgpu_fbdev_fini(adev);
 	r = amdgpu_fini(adev);

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

@@ -1255,6 +1255,15 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 	/* Change the size here instead of the init above so only lpfn is affected */
 	amdgpu_ttm_set_active_vram_size(adev, adev->mc.visible_vram_size);
 
+	/*
+	 *The reserved vram for firmware must be pinned to the specified
+	 *place on the VRAM, so reserve it early.
+	 */
+	r = amdgpu_fw_reserve_vram_init(adev);
+	if (r) {
+		return r;
+	}
+
 	r = amdgpu_bo_create_kernel(adev, adev->mc.stolen_size, PAGE_SIZE,
 				    AMDGPU_GEM_DOMAIN_VRAM,
 				    &adev->stolen_vga_memory,