arch/mips/mm/sc-debugfs.c

   1 /*
   2  * Copyright (C) 2015 Imagination Technologies
   3  * Author: Paul Burton <paul.burton@mips.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License as published by the
   7  * Free Software Foundation; either version 2 of the License, or (at your
   8  * option) any later version.
   9  */
  10
  11 #include <asm/bcache.h>
  12 #include <asm/debug.h>
  13 #include <linux/uaccess.h>
  14 #include <linux/debugfs.h>
  15 #include <linux/init.h>
  16
  17 static ssize_t sc_prefetch_read(struct file *file, char __user *user_buf,
  18                                 size_t count, loff_t *ppos)
  19 {
  20         bool enabled = bc_prefetch_is_enabled();
  21         char buf[3];
  22
  23         buf[0] = enabled ? 'Y' : 'N';
  24         buf[1] = '\n';
  25         buf[2] = 0;
  26
  27         return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
  28 }
  29
  30 static ssize_t sc_prefetch_write(struct file *file,
  31                                  const char __user *user_buf,
  32                                  size_t count, loff_t *ppos)
  33 {
  34         bool enabled;
  35         int err;
  36
  37         err = kstrtobool_from_user(user_buf, count, &enabled);
  38         if (err)
  39                 return err;
  40
  41         if (enabled)
  42                 bc_prefetch_enable();
  43         else
  44                 bc_prefetch_disable();
  45
  46         return count;
  47 }
  48
  49 static const struct file_operations sc_prefetch_fops = {
  50         .open = simple_open,
  51         .llseek = default_llseek,
  52         .read = sc_prefetch_read,
  53         .write = sc_prefetch_write,
  54 };
  55
  56 static int __init sc_debugfs_init(void)
  57 {
  58         struct dentry *dir, *file;
  59
  60         if (!mips_debugfs_dir)
  61                 return -ENODEV;
  62
  63         dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
  64         if (IS_ERR(dir))
  65                 return PTR_ERR(dir);
  66
  67         file = debugfs_create_file("prefetch", S_IRUGO | S_IWUSR, dir,
  68                                    NULL, &sc_prefetch_fops);
  69         if (!file)
  70                 return -ENOMEM;
  71
  72         return 0;
  73 }
  74 late_initcall(sc_debugfs_init);