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         char buf[32];
  35         ssize_t buf_size;
  36         bool enabled;
  37         int err;
  38
  39         buf_size = min(count, sizeof(buf) - 1);
  40         if (copy_from_user(buf, user_buf, buf_size))
  41                 return -EFAULT;
  42
  43         buf[buf_size] = '\0';
  44         err = strtobool(buf, &enabled);
  45         if (err)
  46                 return err;
  47
  48         if (enabled)
  49                 bc_prefetch_enable();
  50         else
  51                 bc_prefetch_disable();
  52
  53         return count;
  54 }
  55
  56 static const struct file_operations sc_prefetch_fops = {
  57         .open = simple_open,
  58         .llseek = default_llseek,
  59         .read = sc_prefetch_read,
  60         .write = sc_prefetch_write,
  61 };
  62
  63 static int __init sc_debugfs_init(void)
  64 {
  65         struct dentry *dir, *file;
  66
  67         if (!mips_debugfs_dir)
  68                 return -ENODEV;
  69
  70         dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
  71         if (IS_ERR(dir))
  72                 return PTR_ERR(dir);
  73
  74         file = debugfs_create_file("prefetch", S_IRUGO | S_IWUSR, dir,
  75                                    NULL, &sc_prefetch_fops);
  76         if (!file)
  77                 return -ENOMEM;
  78
  79         return 0;
  80 }
  81 late_initcall(sc_debugfs_init);