LXR linux/arch/mips/mm/sc-debugfs.c

   1/*
   2 * Copyright (C) 2015 Imagination Technologies
   3 * Author: Paul Burton <paul.burton@imgtec.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 <asm/uaccess.h>
  14#include <linux/debugfs.h>
  15#include <linux/init.h>
  16
  17static 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
  30static 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
  56static 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
  63static 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 (IS_ERR(file))
  77                return PTR_ERR(file);
  78
  79        return 0;
  80}
  81late_initcall(sc_debugfs_init);
  82