arch/x86/platform/efi/efi-bgrt.c

   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
  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 || bgrt_tab->status != 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 = early_memremap(bgrt_tab->image_address,
  53                                        sizeof(bmp_header));
  54                 ioremapped = true;
  55                 if (!image)
  56                         return;
  57         }
  58
  59         memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
  60         if (ioremapped)
  61                 early_iounmap(image, sizeof(bmp_header));
  62         bgrt_image_size = bmp_header.size;
  63
  64         bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL);
  65         if (!bgrt_image)
  66                 return;
  67
  68         if (ioremapped) {
  69                 image = early_memremap(bgrt_tab->image_address,
  70                                        bmp_header.size);
  71                 if (!image) {
  72                         kfree(bgrt_image);
  73                         bgrt_image = NULL;
  74                         return;
  75                 }
  76         }
  77
  78         memcpy_fromio(bgrt_image, image, bgrt_image_size);
  79         if (ioremapped)
  80                 early_iounmap(image, bmp_header.size);
  81 }