1 files changed, 105 insertions, 0 deletions
diff --git a/kernel/arch/x86/platform/efi/efi-bgrt.c b/kernel/arch/x86/platform/efi/efi-bgrt.c
new file mode 100644
index 000000000..d7f997f7c
--- /dev/null
+++ b/kernel/arch/x86/platform/efi/efi-bgrt.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2012 Intel Corporation
+ * Author: Josh Triplett <josh@joshtriplett.org>
+ *
+ * Based on the bgrt driver:
+ * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
+ * Author: Matthew Garrett
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/acpi.h>
+#include <linux/efi.h>
+#include <linux/efi-bgrt.h>
+
+struct acpi_table_bgrt *bgrt_tab;
+void *__initdata bgrt_image;
+size_t __initdata bgrt_image_size;
+
+struct bmp_header {
+	u16 id;
+	u32 size;
+} __packed;
+
+void __init efi_bgrt_init(void)
+{
+	acpi_status status;
+	void __iomem *image;
+	bool ioremapped = false;
+	struct bmp_header bmp_header;
+
+	if (acpi_disabled)
+		return;
+
+	status = acpi_get_table("BGRT", 0,
+	                        (struct acpi_table_header **)&bgrt_tab);
+	if (ACPI_FAILURE(status))
+		return;
+
+	if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
+		pr_err("Ignoring BGRT: invalid length %u (expected %zu)\n",
+		       bgrt_tab->header.length, sizeof(*bgrt_tab));
+		return;
+	}
+	if (bgrt_tab->version != 1) {
+		pr_err("Ignoring BGRT: invalid version %u (expected 1)\n",
+		       bgrt_tab->version);
+		return;
+	}
+	if (bgrt_tab->status != 1) {
+		pr_err("Ignoring BGRT: invalid status %u (expected 1)\n",
+		       bgrt_tab->status);
+		return;
+	}
+	if (bgrt_tab->image_type != 0) {
+		pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n",
+		       bgrt_tab->image_type);
+		return;
+	}
+	if (!bgrt_tab->image_address) {
+		pr_err("Ignoring BGRT: null image address\n");
+		return;
+	}
+
+	image = efi_lookup_mapped_addr(bgrt_tab->image_address);
+	if (!image) {
+		image = early_ioremap(bgrt_tab->image_address,
+				       sizeof(bmp_header));
+		ioremapped = true;
+		if (!image) {
+			pr_err("Ignoring BGRT: failed to map image header memory\n");
+			return;
+		}
+	}
+
+	memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
+	if (ioremapped)
+		early_iounmap(image, sizeof(bmp_header));
+	bgrt_image_size = bmp_header.size;
+
+	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
+	if (!bgrt_image) {
+		pr_err("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
+		       bgrt_image_size);
+		return;
+	}
+
+	if (ioremapped) {
+		image = early_ioremap(bgrt_tab->image_address,
+				       bmp_header.size);
+		if (!image) {
+			pr_err("Ignoring BGRT: failed to map image memory\n");
+			kfree(bgrt_image);
+			bgrt_image = NULL;
+			return;
+		}
+	}
+
+	memcpy_fromio(bgrt_image, image, bgrt_image_size);
+	if (ioremapped)
+		early_iounmap(image, bmp_header.size);
+}