1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * Copyright 2012 Intel Corporation
4*4882a593Smuzhiyun * Author: Josh Triplett <josh@joshtriplett.org>
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * Based on the bgrt driver:
7*4882a593Smuzhiyun * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
8*4882a593Smuzhiyun * Author: Matthew Garrett
9*4882a593Smuzhiyun */
10*4882a593Smuzhiyun
11*4882a593Smuzhiyun #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include <linux/kernel.h>
14*4882a593Smuzhiyun #include <linux/init.h>
15*4882a593Smuzhiyun #include <linux/acpi.h>
16*4882a593Smuzhiyun #include <linux/efi.h>
17*4882a593Smuzhiyun #include <linux/efi-bgrt.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun struct acpi_table_bgrt bgrt_tab;
20*4882a593Smuzhiyun size_t bgrt_image_size;
21*4882a593Smuzhiyun
22*4882a593Smuzhiyun struct bmp_header {
23*4882a593Smuzhiyun u16 id;
24*4882a593Smuzhiyun u32 size;
25*4882a593Smuzhiyun } __packed;
26*4882a593Smuzhiyun
efi_bgrt_init(struct acpi_table_header * table)27*4882a593Smuzhiyun void __init efi_bgrt_init(struct acpi_table_header *table)
28*4882a593Smuzhiyun {
29*4882a593Smuzhiyun void *image;
30*4882a593Smuzhiyun struct bmp_header bmp_header;
31*4882a593Smuzhiyun struct acpi_table_bgrt *bgrt = &bgrt_tab;
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun if (acpi_disabled)
34*4882a593Smuzhiyun return;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun if (!efi_enabled(EFI_MEMMAP))
37*4882a593Smuzhiyun return;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun if (table->length < sizeof(bgrt_tab)) {
40*4882a593Smuzhiyun pr_notice("Ignoring BGRT: invalid length %u (expected %zu)\n",
41*4882a593Smuzhiyun table->length, sizeof(bgrt_tab));
42*4882a593Smuzhiyun return;
43*4882a593Smuzhiyun }
44*4882a593Smuzhiyun *bgrt = *(struct acpi_table_bgrt *)table;
45*4882a593Smuzhiyun /*
46*4882a593Smuzhiyun * Only version 1 is defined but some older laptops (seen on Lenovo
47*4882a593Smuzhiyun * Ivy Bridge models) have a correct version 1 BGRT table with the
48*4882a593Smuzhiyun * version set to 0, so we accept version 0 and 1.
49*4882a593Smuzhiyun */
50*4882a593Smuzhiyun if (bgrt->version > 1) {
51*4882a593Smuzhiyun pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
52*4882a593Smuzhiyun bgrt->version);
53*4882a593Smuzhiyun goto out;
54*4882a593Smuzhiyun }
55*4882a593Smuzhiyun if (bgrt->image_type != 0) {
56*4882a593Smuzhiyun pr_notice("Ignoring BGRT: invalid image type %u (expected 0)\n",
57*4882a593Smuzhiyun bgrt->image_type);
58*4882a593Smuzhiyun goto out;
59*4882a593Smuzhiyun }
60*4882a593Smuzhiyun if (!bgrt->image_address) {
61*4882a593Smuzhiyun pr_notice("Ignoring BGRT: null image address\n");
62*4882a593Smuzhiyun goto out;
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun if (efi_mem_type(bgrt->image_address) != EFI_BOOT_SERVICES_DATA) {
66*4882a593Smuzhiyun pr_notice("Ignoring BGRT: invalid image address\n");
67*4882a593Smuzhiyun goto out;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun image = early_memremap(bgrt->image_address, sizeof(bmp_header));
70*4882a593Smuzhiyun if (!image) {
71*4882a593Smuzhiyun pr_notice("Ignoring BGRT: failed to map image header memory\n");
72*4882a593Smuzhiyun goto out;
73*4882a593Smuzhiyun }
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun memcpy(&bmp_header, image, sizeof(bmp_header));
76*4882a593Smuzhiyun early_memunmap(image, sizeof(bmp_header));
77*4882a593Smuzhiyun if (bmp_header.id != 0x4d42) {
78*4882a593Smuzhiyun pr_notice("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
79*4882a593Smuzhiyun bmp_header.id);
80*4882a593Smuzhiyun goto out;
81*4882a593Smuzhiyun }
82*4882a593Smuzhiyun bgrt_image_size = bmp_header.size;
83*4882a593Smuzhiyun efi_mem_reserve(bgrt->image_address, bgrt_image_size);
84*4882a593Smuzhiyun
85*4882a593Smuzhiyun return;
86*4882a593Smuzhiyun out:
87*4882a593Smuzhiyun memset(bgrt, 0, sizeof(bgrt_tab));
88*4882a593Smuzhiyun }
89