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
15static void *bgrt_image;
16static 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	static struct kobj_attribute bgrt_attr_##_name = __ATTR_RO(_name)
25
26BGRT_SHOW(version, version);
27BGRT_SHOW(status, status);
28BGRT_SHOW(type, image_type);
29BGRT_SHOW(xoffset, image_offset_x);
30BGRT_SHOW(yoffset, image_offset_y);
31
32static 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
39static BIN_ATTR_RO(image, 0);	/* size gets filled in later */
40
41static 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
50static struct bin_attribute *bgrt_bin_attributes[] = {
51	&bin_attr_image,
52	NULL,
53};
54
55static const struct attribute_group bgrt_attribute_group = {
56	.attrs = bgrt_attributes,
57	.bin_attrs = bgrt_bin_attributes,
58};
59
60int __init acpi_parse_bgrt(struct acpi_table_header *table)
61{
62	efi_bgrt_init(table);
63	return 0;
64}
65
66static 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
95out_kobject:
96	kobject_put(bgrt_kobj);
97out_memmap:
98	memunmap(bgrt_image);
99	return ret;
100}
101device_initcall(bgrt_init);
102