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
memconsole_read(struct file * filp,struct kobject * kobp,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)16 static 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
29 static struct bin_attribute memconsole_bin_attr = {
30 .attr = {.name = "log", .mode = 0444},
31 .read = memconsole_read,
32 };
33
memconsole_setup(ssize_t (* read_func)(char *,loff_t,size_t))34 void memconsole_setup(ssize_t (*read_func)(char *, loff_t, size_t))
35 {
36 memconsole_bin_attr.private = read_func;
37 }
38 EXPORT_SYMBOL(memconsole_setup);
39
memconsole_sysfs_init(void)40 int memconsole_sysfs_init(void)
41 {
42 return sysfs_create_bin_file(firmware_kobj, &memconsole_bin_attr);
43 }
44 EXPORT_SYMBOL(memconsole_sysfs_init);
45
memconsole_exit(void)46 void memconsole_exit(void)
47 {
48 sysfs_remove_bin_file(firmware_kobj, &memconsole_bin_attr);
49 }
50 EXPORT_SYMBOL(memconsole_exit);
51
52 MODULE_AUTHOR("Google, Inc.");
53 MODULE_LICENSE("GPL");
54