1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * memconsole.c
4 *
5 * Architecture-independent parts of the memory based BIOS console.
6 *
7 * Copyright 2017 Google Inc.
8 */
9
10#include <linux/sysfs.h>
11#include <linux/kobject.h>
12#include <linux/module.h>
13
14#include "memconsole.h"
15
16static ssize_t memconsole_read(struct file *filp, struct kobject *kobp,
17			       struct bin_attribute *bin_attr, char *buf,
18			       loff_t pos, size_t count)
19{
20	ssize_t (*memconsole_read_func)(char *, loff_t, size_t);
21
22	memconsole_read_func = bin_attr->private;
23	if (WARN_ON_ONCE(!memconsole_read_func))
24		return -EIO;
25
26	return memconsole_read_func(buf, pos, count);
27}
28
29static struct bin_attribute memconsole_bin_attr = {
30	.attr = {.name = "log", .mode = 0444},
31	.read = memconsole_read,
32};
33
34void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t))
35{
36	memconsole_bin_attr.private = read_func;
37}
38EXPORT_SYMBOL(memconsole_setup);
39
40int memconsole_sysfs_init(void)
41{
42	return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
43}
44EXPORT_SYMBOL(memconsole_sysfs_init);
45
46void memconsole_exit(void)
47{
48	sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
49}
50EXPORT_SYMBOL(memconsole_exit);
51
52MODULE_AUTHOR("Google, Inc.");
53MODULE_LICENSE("GPL");
54