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152 lines
3.4 KiB
152 lines
3.4 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Driver for the Intel SCU IPC mechanism |
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* |
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* (C) Copyright 2008-2010 Intel Corporation |
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* Author: Sreedhara DS ([email protected]) |
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* |
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* This driver provides IOCTL interfaces to call Intel SCU IPC driver API. |
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*/ |
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#include <linux/errno.h> |
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#include <linux/fcntl.h> |
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#include <linux/fs.h> |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/sched.h> |
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#include <linux/slab.h> |
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#include <linux/types.h> |
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#include <linux/uaccess.h> |
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#include <asm/intel_scu_ipc.h> |
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static int major; |
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struct intel_scu_ipc_dev *scu; |
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static DEFINE_MUTEX(scu_lock); |
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/* IOCTL commands */ |
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#define INTE_SCU_IPC_REGISTER_READ 0 |
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#define INTE_SCU_IPC_REGISTER_WRITE 1 |
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#define INTE_SCU_IPC_REGISTER_UPDATE 2 |
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struct scu_ipc_data { |
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u32 count; /* No. of registers */ |
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u16 addr[5]; /* Register addresses */ |
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u8 data[5]; /* Register data */ |
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u8 mask; /* Valid for read-modify-write */ |
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}; |
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/** |
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* scu_reg_access - implement register access ioctls |
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* @cmd: command we are doing (read/write/update) |
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* @data: kernel copy of ioctl data |
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* |
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* Allow the user to perform register accesses on the SCU via the |
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* kernel interface |
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*/ |
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static int scu_reg_access(u32 cmd, struct scu_ipc_data *data) |
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{ |
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unsigned int count = data->count; |
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if (count == 0 || count == 3 || count > 4) |
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return -EINVAL; |
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switch (cmd) { |
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case INTE_SCU_IPC_REGISTER_READ: |
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return intel_scu_ipc_dev_readv(scu, data->addr, data->data, count); |
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case INTE_SCU_IPC_REGISTER_WRITE: |
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return intel_scu_ipc_dev_writev(scu, data->addr, data->data, count); |
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case INTE_SCU_IPC_REGISTER_UPDATE: |
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return intel_scu_ipc_dev_update(scu, data->addr[0], data->data[0], |
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data->mask); |
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default: |
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return -ENOTTY; |
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} |
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} |
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/** |
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* scu_ipc_ioctl - control ioctls for the SCU |
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* @fp: file handle of the SCU device |
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* @cmd: ioctl coce |
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* @arg: pointer to user passed structure |
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* |
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* Support the I/O and firmware flashing interfaces of the SCU |
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*/ |
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static long scu_ipc_ioctl(struct file *fp, unsigned int cmd, |
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unsigned long arg) |
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{ |
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int ret; |
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struct scu_ipc_data data; |
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void __user *argp = (void __user *)arg; |
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if (!capable(CAP_SYS_RAWIO)) |
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return -EPERM; |
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if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data))) |
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return -EFAULT; |
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ret = scu_reg_access(cmd, &data); |
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if (ret < 0) |
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return ret; |
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if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data))) |
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return -EFAULT; |
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return 0; |
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} |
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static int scu_ipc_open(struct inode *inode, struct file *file) |
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{ |
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int ret = 0; |
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/* Only single open at the time */ |
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mutex_lock(&scu_lock); |
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if (scu) { |
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ret = -EBUSY; |
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goto unlock; |
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} |
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scu = intel_scu_ipc_dev_get(); |
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if (!scu) |
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ret = -ENODEV; |
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unlock: |
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mutex_unlock(&scu_lock); |
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return ret; |
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} |
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static int scu_ipc_release(struct inode *inode, struct file *file) |
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{ |
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mutex_lock(&scu_lock); |
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intel_scu_ipc_dev_put(scu); |
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scu = NULL; |
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mutex_unlock(&scu_lock); |
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return 0; |
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} |
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static const struct file_operations scu_ipc_fops = { |
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.unlocked_ioctl = scu_ipc_ioctl, |
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.open = scu_ipc_open, |
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.release = scu_ipc_release, |
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}; |
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static int __init ipc_module_init(void) |
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{ |
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major = register_chrdev(0, "intel_mid_scu", &scu_ipc_fops); |
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if (major < 0) |
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return major; |
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return 0; |
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} |
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static void __exit ipc_module_exit(void) |
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{ |
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unregister_chrdev(major, "intel_mid_scu"); |
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} |
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module_init(ipc_module_init); |
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module_exit(ipc_module_exit); |
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MODULE_LICENSE("GPL v2"); |
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MODULE_DESCRIPTION("Utility driver for intel scu ipc"); |
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MODULE_AUTHOR("Sreedhara <[email protected]>");
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