1/*
2 * Copyright 2012 Intel Corporation
3 * Author: Josh Triplett <josh@joshtriplett.org>
4 *
5 * Based on the bgrt driver:
6 * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
7 * Author: Matthew Garrett
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 */
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/acpi.h>
16#include <linux/efi.h>
17#include <linux/efi-bgrt.h>
18
19struct acpi_table_bgrt *bgrt_tab;
20void *__initdata bgrt_image;
21size_t __initdata bgrt_image_size;
22
23struct bmp_header {
24	u16 id;
25	u32 size;
26} __packed;
27
28void __init efi_bgrt_init(void)
29{
30	acpi_status status;
31	void __iomem *image;
32	bool ioremapped = false;
33	struct bmp_header bmp_header;
34
35	if (acpi_disabled)
36		return;
37
38	status = acpi_get_table("BGRT", 0,
39	                        (struct acpi_table_header **)&bgrt_tab);
40	if (ACPI_FAILURE(status))
41		return;
42
43	if (bgrt_tab->header.length < sizeof(*bgrt_tab)) {
44		pr_err("Ignoring BGRT: invalid length %u (expected %zu)\n",
45		       bgrt_tab->header.length, sizeof(*bgrt_tab));
46		return;
47	}
48	if (bgrt_tab->version != 1) {
49		pr_err("Ignoring BGRT: invalid version %u (expected 1)\n",
50		       bgrt_tab->version);
51		return;
52	}
53	if (bgrt_tab->status != 1) {
54		pr_err("Ignoring BGRT: invalid status %u (expected 1)\n",
55		       bgrt_tab->status);
56		return;
57	}
58	if (bgrt_tab->image_type != 0) {
59		pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n",
60		       bgrt_tab->image_type);
61		return;
62	}
63	if (!bgrt_tab->image_address) {
64		pr_err("Ignoring BGRT: null image address\n");
65		return;
66	}
67
68	image = efi_lookup_mapped_addr(bgrt_tab->image_address);
69	if (!image) {
70		image = early_ioremap(bgrt_tab->image_address,
71				       sizeof(bmp_header));
72		ioremapped = true;
73		if (!image) {
74			pr_err("Ignoring BGRT: failed to map image header memory\n");
75			return;
76		}
77	}
78
79	memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
80	if (ioremapped)
81		early_iounmap(image, sizeof(bmp_header));
82	bgrt_image_size = bmp_header.size;
83
84	bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
85	if (!bgrt_image) {
86		pr_err("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
87		       bgrt_image_size);
88		return;
89	}
90
91	if (ioremapped) {
92		image = early_ioremap(bgrt_tab->image_address,
93				       bmp_header.size);
94		if (!image) {
95			pr_err("Ignoring BGRT: failed to map image memory\n");
96			kfree(bgrt_image);
97			bgrt_image = NULL;
98			return;
99		}
100	}
101
102	memcpy_fromio(bgrt_image, image, bgrt_image_size);
103	if (ioremapped)
104		early_iounmap(image, bmp_header.size);
105}
106