1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * arch/arm/common/bL_switcher_dummy_if.c -- b.L switcher dummy interface
4 *
5 * Created by:	Nicolas Pitre, November 2012
6 * Copyright:	(C) 2012-2013  Linaro Limited
7 *
8 * Dummy interface to user space for debugging purpose only.
9 */
10
11#include <linux/init.h>
12#include <linux/module.h>
13#include <linux/fs.h>
14#include <linux/miscdevice.h>
15#include <linux/uaccess.h>
16#include <asm/bL_switcher.h>
17
18static ssize_t bL_switcher_write(struct file *file, const char __user *buf,
19			size_t len, loff_t *pos)
20{
21	unsigned char val[3];
22	unsigned int cpu, cluster;
23	int ret;
24
25	pr_debug("%s\n", __func__);
26
27	if (len < 3)
28		return -EINVAL;
29
30	if (copy_from_user(val, buf, 3))
31		return -EFAULT;
32
33	/* format: <cpu#>,<cluster#> */
34	if (val[0] < '0' || val[0] > '9' ||
35	    val[1] != ',' ||
36	    val[2] < '0' || val[2] > '1')
37		return -EINVAL;
38
39	cpu = val[0] - '0';
40	cluster = val[2] - '0';
41	ret = bL_switch_request(cpu, cluster);
42
43	return ret ? : len;
44}
45
46static const struct file_operations bL_switcher_fops = {
47	.write		= bL_switcher_write,
48	.owner	= THIS_MODULE,
49};
50
51static struct miscdevice bL_switcher_device = {
52	MISC_DYNAMIC_MINOR,
53	"b.L_switcher",
54	&bL_switcher_fops
55};
56module_misc_device(bL_switcher_device);
57
58MODULE_AUTHOR("Nicolas Pitre <nico@linaro.org>");
59MODULE_LICENSE("GPL v2");
60MODULE_DESCRIPTION("big.LITTLE switcher dummy user interface");
61