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/acpi.h>
  15 #include <linux/efi.h>
  16 #include <linux/efi-bgrt.h>
  17
  18 struct acpi_table_bgrt *bgrt_tab;
  19 void *bgrt_image;
  20 size_t bgrt_image_size;
  21
  22 struct bmp_header {
  23         u16 id;
  24         u32 size;
  25 } __packed;
  26
  27 void efi_bgrt_init(void)
  28 {
  29         acpi_status status;
  30         void __iomem *image;
  31         bool ioremapped = false;
  32         struct bmp_header bmp_header;
  33
  34         if (acpi_disabled)
  35                 return;
  36
  37         status = acpi_get_table("BGRT", 0,
  38                                 (struct acpi_table_header **)&bgrt_tab);
  39         if (ACPI_FAILURE(status))
  40                 return;
  41
  42         if (bgrt_tab->header.length < sizeof(*bgrt_tab))
  43                 return;
  44         if (bgrt_tab->version != 1)
  45                 return;
  46         if (bgrt_tab->image_type != 0 || !bgrt_tab->image_address)
  47                 return;
  48
  49         image = efi_lookup_mapped_addr(bgrt_tab->image_address);
  50         if (!image) {
  51                 image = ioremap(bgrt_tab->image_address, sizeof(bmp_header));
  52                 ioremapped = true;
  53                 if (!image)
  54                         return;
  55         }
  56
  57         memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
  58         if (ioremapped)
  59                 iounmap(image);
  60         bgrt_image_size = bmp_header.size;
  61
  62         bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL);
  63         if (!bgrt_image)
  64                 return;
  65
  66         if (ioremapped) {
  67                 image = ioremap(bgrt_tab->image_address, bmp_header.size);
  68                 if (!image) {
  69                         kfree(bgrt_image);
  70                         bgrt_image = NULL;
  71                         return;
  72                 }
  73         }
  74
  75         memcpy_fromio(bgrt_image, image, bgrt_image_size);
  76         if (ioremapped)
  77                 iounmap(image);
  78 }