LXR linux/drivers/firmware/google/memconsole.c

   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