drivers/acpi/bgrt.c

   1 /*
   2  * BGRT boot graphic support
   3  * Authors: Matthew Garrett, Josh Triplett <josh@joshtriplett.org>
   4  * Copyright 2012 Red Hat, Inc <mjg@redhat.com>
   5  * Copyright 2012 Intel Corporation
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/device.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/efi-bgrt.h>
  17
  18 static void *bgrt_image;
  19 static struct kobject *bgrt_kobj;
  20
  21 static ssize_t show_version(struct device *dev,
  22                             struct device_attribute *attr, char *buf)
  23 {
  24         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.version);
  25 }
  26 static DEVICE_ATTR(version, S_IRUGO, show_version, NULL);
  27
  28 static ssize_t show_status(struct device *dev,
  29                            struct device_attribute *attr, char *buf)
  30 {
  31         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.status);
  32 }
  33 static DEVICE_ATTR(status, S_IRUGO, show_status, NULL);
  34
  35 static ssize_t show_type(struct device *dev,
  36                          struct device_attribute *attr, char *buf)
  37 {
  38         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_type);
  39 }
  40 static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
  41
  42 static ssize_t show_xoffset(struct device *dev,
  43                             struct device_attribute *attr, char *buf)
  44 {
  45         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_x);
  46 }
  47 static DEVICE_ATTR(xoffset, S_IRUGO, show_xoffset, NULL);
  48
  49 static ssize_t show_yoffset(struct device *dev,
  50                             struct device_attribute *attr, char *buf)
  51 {
  52         return snprintf(buf, PAGE_SIZE, "%d\n", bgrt_tab.image_offset_y);
  53 }
  54 static DEVICE_ATTR(yoffset, S_IRUGO, show_yoffset, NULL);
  55
  56 static ssize_t image_read(struct file *file, struct kobject *kobj,
  57                struct bin_attribute *attr, char *buf, loff_t off, size_t count)
  58 {
  59         memcpy(buf, attr->private + off, count);
  60         return count;
  61 }
  62
  63 static BIN_ATTR_RO(image, 0);   /* size gets filled in later */
  64
  65 static struct attribute *bgrt_attributes[] = {
  66         &dev_attr_version.attr,
  67         &dev_attr_status.attr,
  68         &dev_attr_type.attr,
  69         &dev_attr_xoffset.attr,
  70         &dev_attr_yoffset.attr,
  71         NULL,
  72 };
  73
  74 static struct bin_attribute *bgrt_bin_attributes[] = {
  75         &bin_attr_image,
  76         NULL,
  77 };
  78
  79 static struct attribute_group bgrt_attribute_group = {
  80         .attrs = bgrt_attributes,
  81         .bin_attrs = bgrt_bin_attributes,
  82 };
  83
  84 static int __init bgrt_init(void)
  85 {
  86         int ret;
  87
  88         if (!bgrt_tab.image_address)
  89                 return -ENODEV;
  90
  91         bgrt_image = memremap(bgrt_tab.image_address, bgrt_image_size,
  92                               MEMREMAP_WB);
  93         if (!bgrt_image) {
  94                 pr_notice("Ignoring BGRT: failed to map image memory\n");
  95                 return -ENOMEM;
  96         }
  97
  98         bin_attr_image.private = bgrt_image;
  99         bin_attr_image.size = bgrt_image_size;
 100
 101         bgrt_kobj = kobject_create_and_add("bgrt", acpi_kobj);
 102         if (!bgrt_kobj) {
 103                 ret = -EINVAL;
 104                 goto out_memmap;
 105         }
 106
 107         ret = sysfs_create_group(bgrt_kobj, &bgrt_attribute_group);
 108         if (ret)
 109                 goto out_kobject;
 110
 111         return 0;
 112
 113 out_kobject:
 114         kobject_put(bgrt_kobj);
 115 out_memmap:
 116         memunmap(bgrt_image);
 117         return ret;
 118 }
 119 device_initcall(bgrt_init);