drm/radeon/kms: add support for DP modesetting

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
index 85abc08..6578d19 100644
--- a/drivers/gpu/drm/radeon/atom.c
+++ b/drivers/gpu/drm/radeon/atom.c
@@ -1214,3 +1214,28 @@
 		*crev = CU8(idx + 3);
 	return;
 }
+
+int atom_allocate_fb_scratch(struct atom_context *ctx)
+{
+	int index = GetIndexIntoMasterTable(DATA, VRAM_UsageByFirmware);
+	uint16_t data_offset;
+	int usage_bytes;
+	struct _ATOM_VRAM_USAGE_BY_FIRMWARE *firmware_usage;
+
+	atom_parse_data_header(ctx, index, NULL, NULL, NULL, &data_offset);
+
+	firmware_usage = (struct _ATOM_VRAM_USAGE_BY_FIRMWARE *)(ctx->bios + data_offset);
+
+	DRM_DEBUG("atom firmware requested %08x %dkb\n",
+		  firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware,
+		  firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb);
+
+	usage_bytes = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb * 1024;
+	if (usage_bytes == 0)
+		usage_bytes = 20 * 1024;
+	/* allocate some scratch memory */
+	ctx->scratch = kzalloc(usage_bytes, GFP_KERNEL);
+	if (!ctx->scratch)
+		return -ENOMEM;
+	return 0;
+}