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
18 static 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] < '' || val[0] > '9' ||
35 val[1] != ',' ||
36 val[2] < '' || val[2] > '1')
37 return -EINVAL;
38
39 cpu = val[0] - '';
40 cluster = val[2] - '';
41 ret = bL_switch_request(cpu, cluster);
42
43 return ret ? : len;
44 }
45
46 static const struct file_operations bL_switcher_fops = {
47 .write = bL_switcher_write,
48 .owner = THIS_MODULE,
49 };
50
51 static struct miscdevice bL_switcher_device = {
52 MISC_DYNAMIC_MINOR,
53 "b.L_switcher",
54 &bL_switcher_fops
55 };
56 module_misc_device(bL_switcher_device);
57
58 MODULE_AUTHOR("Nicolas Pitre <nico@linaro.org>");
59 MODULE_LICENSE("GPL v2");
60 MODULE_DESCRIPTION("big.LITTLE switcher dummy user interface");
61
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