summaryrefslogtreecommitdiffstats
path: root/drivers/platform/x86/intel_scu_ipcutil.c
blob: 7d87cbd4b9c63c7ceba40284041265315efe6663 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
// SPDX-License-Identifier: GPL-2.0
/*
 * Driver for the Intel SCU IPC mechanism
 *
 * (C) Copyright 2008-2010 Intel Corporation
 * Author: Sreedhara DS (sreedhara.ds@intel.com)
 *
 * This driver provides IOCTL interfaces to call Intel SCU IPC driver API.
 */

#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/uaccess.h>

#include <asm/intel_scu_ipc.h>

static int major;

static struct intel_scu_ipc_dev *scu;
static DEFINE_MUTEX(scu_lock);

/* IOCTL commands */
#define	INTE_SCU_IPC_REGISTER_READ	0
#define INTE_SCU_IPC_REGISTER_WRITE	1
#define INTE_SCU_IPC_REGISTER_UPDATE	2

struct scu_ipc_data {
	u32     count;  /* No. of registers */
	u16     addr[5]; /* Register addresses */
	u8      data[5]; /* Register data */
	u8      mask; /* Valid for read-modify-write */
};

/**
 *	scu_reg_access		-	implement register access ioctls
 *	@cmd: command we are doing (read/write/update)
 *	@data: kernel copy of ioctl data
 *
 *	Allow the user to perform register accesses on the SCU via the
 *	kernel interface
 */

static int scu_reg_access(u32 cmd, struct scu_ipc_data  *data)
{
	unsigned int count = data->count;

	if (count == 0 || count == 3 || count > 4)
		return -EINVAL;

	switch (cmd) {
	case INTE_SCU_IPC_REGISTER_READ:
		return intel_scu_ipc_dev_readv(scu, data->addr, data->data, count);
	case INTE_SCU_IPC_REGISTER_WRITE:
		return intel_scu_ipc_dev_writev(scu, data->addr, data->data, count);
	case INTE_SCU_IPC_REGISTER_UPDATE:
		return intel_scu_ipc_dev_update(scu, data->addr[0], data->data[0],
						data->mask);
	default:
		return -ENOTTY;
	}
}

/**
 *	scu_ipc_ioctl		-	control ioctls for the SCU
 *	@fp: file handle of the SCU device
 *	@cmd: ioctl coce
 *	@arg: pointer to user passed structure
 *
 *	Support the I/O and firmware flashing interfaces of the SCU
 */
static long scu_ipc_ioctl(struct file *fp, unsigned int cmd,
							unsigned long arg)
{
	int ret;
	struct scu_ipc_data  data;
	void __user *argp = (void __user *)arg;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data)))
		return -EFAULT;
	ret = scu_reg_access(cmd, &data);
	if (ret < 0)
		return ret;
	if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data)))
		return -EFAULT;
	return 0;
}

static int scu_ipc_open(struct inode *inode, struct file *file)
{
	int ret = 0;

	/* Only single open at the time */
	mutex_lock(&scu_lock);
	if (scu) {
		ret = -EBUSY;
		goto unlock;
	}

	scu = intel_scu_ipc_dev_get();
	if (!scu)
		ret = -ENODEV;

unlock:
	mutex_unlock(&scu_lock);
	return ret;
}

static int scu_ipc_release(struct inode *inode, struct file *file)
{
	mutex_lock(&scu_lock);
	intel_scu_ipc_dev_put(scu);
	scu = NULL;
	mutex_unlock(&scu_lock);

	return 0;
}

static const struct file_operations scu_ipc_fops = {
	.unlocked_ioctl = scu_ipc_ioctl,
	.open = scu_ipc_open,
	.release = scu_ipc_release,
};

static int __init ipc_module_init(void)
{
	major = register_chrdev(0, "intel_mid_scu", &scu_ipc_fops);
	if (major < 0)
		return major;

	return 0;
}

static void __exit ipc_module_exit(void)
{
	unregister_chrdev(major, "intel_mid_scu");
}

module_init(ipc_module_init);
module_exit(ipc_module_exit);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Utility driver for intel scu ipc");
MODULE_AUTHOR("Sreedhara <sreedhara.ds@intel.com>");