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 return;
45 if (bgrt_tab->version != 1)
46 return;
47 if (bgrt_tab->image_type != 0 || !bgrt_tab->image_address)
48 return;
49
50 image = efi_lookup_mapped_addr(bgrt_tab->image_address);
51 if (!image) {
52 image = ioremap(bgrt_tab->image_address, sizeof(bmp_header));
53 ioremapped = true;
54 if (!image)
55 return;
56 }
57
58 memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
59 if (ioremapped)
60 iounmap(image);
61 bgrt_image_size = bmp_header.size;
62
63 bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL);
64 if (!bgrt_image)
65 return;
66
67 if (ioremapped) {
68 image = ioremap(bgrt_tab->image_address, bmp_header.size);
69 if (!image) {
70 kfree(bgrt_image);
71 bgrt_image = NULL;
72 return;
73 }
74 }
75
76 memcpy_fromio(bgrt_image, image, bgrt_image_size);
77 if (ioremapped)
78 iounmap(image);
79 }
80