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// 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;
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>");
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