Orange Pi5 kernel

// 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>");