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(to: val, from: buf, n: 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

source code of linux/arch/arm/common/bL_switcher_dummy_if.c