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
19 struct acpi_table_bgrt *bgrt_tab;
20 void *__initdata bgrt_image;
21 size_t __initdata bgrt_image_size;
22
23 struct bmp_header {
24 u16 id;
25 u32 size;
26 } __packed;
27
efi_bgrt_init(void)28 void __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