drivers/acpi/bgrt.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * BGRT boot graphic support
   4  * Authors: Matthew Garrett, Josh Triplett <josh@joshtriplett.org>
   5  * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
   6  * Copyright 2012 Intel Corporation
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/init.h>
  11 #include <linux/device.h>
  12 #include <linux/sysfs.h>
  13 #include <linux/efi-bgrt.h>
  14
  15 static void *bgrt_image;
  16 static struct kobject *bgrt_kobj;
  17
  18 #define BGRT_SHOW(_name, _member) \
  19         static ssize_t _name##_show(struct kobject *kobj,                       \
  20                                     struct kobj_attribute *attr, char *buf)     \
  21         {                                                                       \
  22                 return sysfs_emit(buf, "%d\n", bgrt_tab._member);               \
  23         }                                                                       \
  24         struct kobj_attribute bgrt_attr_##_name = __ATTR_RO(_name)
  25
  26 BGRT_SHOW(version, version);
  27 BGRT_SHOW(status, status);
  28 BGRT_SHOW(type, image_type);
  29 BGRT_SHOW(xoffset, image_offset_x);
  30 BGRT_SHOW(yoffset, image_offset_y);
  31
  32 static ssize_t image_read(struct file *file, struct kobject *kobj,
  33                struct bin_attribute *attr, char *buf, loff_t off, size_t count)
  34 {
  35         memcpy(buf, attr->private + off, count);
  36         return count;
  37 }
  38
  39 static BIN_ATTR_RO(image, 0);   /* size gets filled in later */
  40
  41 static struct attribute *bgrt_attributes[] = {
  42         &bgrt_attr_version.attr,
  43         &bgrt_attr_status.attr,
  44         &bgrt_attr_type.attr,
  45         &bgrt_attr_xoffset.attr,
  46         &bgrt_attr_yoffset.attr,
  47         NULL,
  48 };
  49
  50 static struct bin_attribute *bgrt_bin_attributes[] = {
  51         &bin_attr_image,
  52         NULL,
  53 };
  54
  55 static const struct attribute_group bgrt_attribute_group = {
  56         .attrs = bgrt_attributes,
  57         .bin_attrs = bgrt_bin_attributes,
  58 };
  59
  60 int __init acpi_parse_bgrt(struct acpi_table_header *table)
  61 {
  62         efi_bgrt_init(table);
  63         return 0;
  64 }
  65
  66 static int __init bgrt_init(void)
  67 {
  68         int ret;
  69
  70         if (!bgrt_tab.image_address)
  71                 return -ENODEV;
  72
  73         bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
  74                               MEMREMAP_WB);
  75         if (!bgrt_image) {
  76                 pr_notice("Ignoring BGRT: failed to map image memory\n");
  77                 return -ENOMEM;
  78         }
  79
  80         bin_attr_image.private = bgrt_image;
  81         bin_attr_image.size = bgrt_image_size;
  82
  83         bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
  84         if (!bgrt_kobj) {
  85                 ret = -EINVAL;
  86                 goto out_memmap;
  87         }
  88
  89         ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
  90         if (ret)
  91                 goto out_kobject;
  92
  93         return 0;
  94
  95 out_kobject:
  96         kobject_put(bgrt_kobj);
  97 out_memmap:
  98         memunmap(bgrt_image);
  99         return ret;
 100 }
 101 device_initcall(bgrt_init);