linux/arch/mips/mm/sc-debugfs.c
Paul Burton d478b088a2 MIPS: Allow L2 prefetch to be configured via debugfs
When debugging or examining the performance of a system it can be useful
to examine the effect of L2 prefetching. Provide an optional debugfs
entry to allow a user to enable or disable L2 prefetching.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/11182/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2015-10-26 09:49:42 +01:00

82 lines
1.8 KiB
C

/*
* Copyright (C) 2015 Imagination Technologies
* Author: Paul Burton <paul.burton@imgtec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include <asm/bcache.h>
#include <asm/debug.h>
#include <asm/uaccess.h>
#include <linux/debugfs.h>
#include <linux/init.h>
static ssize_t sc_prefetch_read(struct file *file, char __user *user_buf,
size_t count, loff_t *ppos)
{
bool enabled = bc_prefetch_is_enabled();
char buf[3];
buf[0] = enabled ? 'Y' : 'N';
buf[1] = '\n';
buf[2] = 0;
return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
}
static ssize_t sc_prefetch_write(struct file *file,
const char __user *user_buf,
size_t count, loff_t *ppos)
{
char buf[32];
ssize_t buf_size;
bool enabled;
int err;
buf_size = min(count, sizeof(buf) - 1);
if (copy_from_user(buf, user_buf, buf_size))
return -EFAULT;
buf[buf_size] = '\0';
err = strtobool(buf, &enabled);
if (err)
return err;
if (enabled)
bc_prefetch_enable();
else
bc_prefetch_disable();
return count;
}
static const struct file_operations sc_prefetch_fops = {
.open = simple_open,
.llseek = default_llseek,
.read = sc_prefetch_read,
.write = sc_prefetch_write,
};
static int __init sc_debugfs_init(void)
{
struct dentry *dir, *file;
if (!mips_debugfs_dir)
return -ENODEV;
dir = debugfs_create_dir("l2cache", mips_debugfs_dir);
if (IS_ERR(dir))
return PTR_ERR(dir);
file = debugfs_create_file("prefetch", S_IRUGO | S_IWUSR, dir,
NULL, &sc_prefetch_fops);
if (IS_ERR(file))
return PTR_ERR(file);
return 0;
}
late_initcall(sc_debugfs_init);