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 static ssize_t show_version(struct device *dev,
  19                             struct device_attribute *attr, char *buf)
  20 {
  21         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version);
  22 }
  23 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
  24
  25 static ssize_t show_status(struct device *dev,
  26                            struct device_attribute *attr, char *buf)
  27 {
  28         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status);
  29 }
  30 static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
  31
  32 static ssize_t show_type(struct device *dev,
  33                          struct device_attribute *attr, char *buf)
  34 {
  35         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type);
  36 }
  37 static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
  38
  39 static ssize_t show_xoffset(struct device *dev,
  40                             struct device_attribute *attr, char *buf)
  41 {
  42         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x);
  43 }
  44 static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);
  45
  46 static ssize_t show_yoffset(struct device *dev,
  47                             struct device_attribute *attr, char *buf)
  48 {
  49         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y);
  50 }
  51 static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);
  52
  53 static ssize_t image_read(struct file *file, struct kobject *kobj,
  54                struct bin_attribute *attr, char *buf, loff_t off, size_t count)
  55 {
  56         memcpy(buf, attr->private + off, count);
  57         return count;
  58 }
  59
  60 static BIN_ATTR_RO(image, 0);   /* size gets filled in later */
  61
  62 static struct attribute *bgrt_attributes[] = {
  63         &dev_attr_version.attr,
  64         &dev_attr_status.attr,
  65         &dev_attr_type.attr,
  66         &dev_attr_xoffset.attr,
  67         &dev_attr_yoffset.attr,
  68         NULL,
  69 };
  70
  71 static struct bin_attribute *bgrt_bin_attributes[] = {
  72         &bin_attr_image,
  73         NULL,
  74 };
  75
  76 static const struct attribute_group bgrt_attribute_group = {
  77         .attrs = bgrt_attributes,
  78         .bin_attrs = bgrt_bin_attributes,
  79 };
  80
  81 int __init acpi_parse_bgrt(struct acpi_table_header *table)
  82 {
  83         efi_bgrt_init(table);
  84         return 0;
  85 }
  86
  87 static int __init bgrt_init(void)
  88 {
  89         int ret;
  90
  91         if (!bgrt_tab.image_address)
  92                 return -ENODEV;
  93
  94         bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
  95                               MEMREMAP_WB);
  96         if (!bgrt_image) {
  97                 pr_notice("Ignoring BGRT: failed to map image memory\n");
  98                 return -ENOMEM;
  99         }
 100
 101         bin_attr_image.private = bgrt_image;
 102         bin_attr_image.size = bgrt_image_size;
 103
 104         bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
 105         if (!bgrt_kobj) {
 106                 ret = -EINVAL;
 107                 goto out_memmap;
 108         }
 109
 110         ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
 111         if (ret)
 112                 goto out_kobject;
 113
 114         return 0;
 115
 116 out_kobject:
 117         kobject_put(bgrt_kobj);
 118 out_memmap:
 119         memunmap(bgrt_image);
 120         return ret;
 121 }
 122 device_initcall(bgrt_init);