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