drivers/platform/x86/intel_scu_ipcutil.c

   1 /*
   2  * intel_scu_ipc.c: Driver for the Intel SCU IPC mechanism
   3  *
   4  * (C) Copyright 2008-2010 Intel Corporation
   5  * Author: Sreedhara DS (sreedhara.ds@intel.com)
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public License
   9  * as published by the Free Software Foundation; version 2
  10  * of the License.
  11  *
  12  * This driver provides ioctl interfaces to call intel scu ipc driver api
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/kernel.h>
  17 #include <linux/errno.h>
  18 #include <linux/types.h>
  19 #include <linux/fs.h>
  20 #include <linux/fcntl.h>
  21 #include <linux/sched.h>
  22 #include <linux/uaccess.h>
  23 #include <linux/slab.h>
  24 #include <linux/init.h>
  25 #include <asm/intel_scu_ipc.h>
  26
  27 static u32 major;
  28
  29 #define MAX_FW_SIZE 264192
  30
  31 /* ioctl commnds */
  32 #define INTE_SCU_IPC_REGISTER_READ      0
  33 #define INTE_SCU_IPC_REGISTER_WRITE     1
  34 #define INTE_SCU_IPC_REGISTER_UPDATE    2
  35 #define INTE_SCU_IPC_FW_UPDATE          0xA2
  36
  37 struct scu_ipc_data {
  38         u32     count;  /* No. of registers */
  39         u16     addr[5]; /* Register addresses */
  40         u8      data[5]; /* Register data */
  41         u8      mask; /* Valid for read-modify-write */
  42 };
  43
  44 /**
  45  *      scu_reg_access          -       implement register access ioctls
  46  *      @cmd: command we are doing (read/write/update)
  47  *      @data: kernel copy of ioctl data
  48  *
  49  *      Allow the user to perform register accesses on the SCU via the
  50  *      kernel interface
  51  */
  52
  53 static int scu_reg_access(u32 cmd, struct scu_ipc_data  *data)
  54 {
  55         int count = data->count;
  56
  57         if (count == 0 || count == 3 || count > 4)
  58                 return -EINVAL;
  59
  60         switch (cmd) {
  61         case INTE_SCU_IPC_REGISTER_READ:
  62                 return intel_scu_ipc_readv(data->addr, data->data, count);
  63         case INTE_SCU_IPC_REGISTER_WRITE:
  64                 return intel_scu_ipc_writev(data->addr, data->data, count);
  65         case INTE_SCU_IPC_REGISTER_UPDATE:
  66                 return intel_scu_ipc_update_register(data->addr[0],
  67                                                     data->data[0], data->mask);
  68         default:
  69                 return -ENOTTY;
  70         }
  71 }
  72
  73 /**
  74  *      scu_ipc_ioctl           -       control ioctls for the SCU
  75  *      @fp: file handle of the SCU device
  76  *      @cmd: ioctl coce
  77  *      @arg: pointer to user passed structure
  78  *
  79  *      Support the I/O and firmware flashing interfaces of the SCU
  80  */
  81 static long scu_ipc_ioctl(struct file *fp, unsigned int cmd,
  82                                                         unsigned long arg)
  83 {
  84         int ret;
  85         struct scu_ipc_data  data;
  86         void __user *argp = (void __user *)arg;
  87
  88         if (!capable(CAP_SYS_RAWIO))
  89                 return -EPERM;
  90
  91         if (cmd == INTE_SCU_IPC_FW_UPDATE) {
  92                         u8 *fwbuf = kmalloc(MAX_FW_SIZE, GFP_KERNEL);
  93                         if (fwbuf == NULL)
  94                                 return -ENOMEM;
  95                         if (copy_from_user(fwbuf, (u8 *)arg, MAX_FW_SIZE)) {
  96                                 kfree(fwbuf);
  97                                 return -EFAULT;
  98                         }
  99                         ret = intel_scu_ipc_fw_update(fwbuf, MAX_FW_SIZE);
 100                         kfree(fwbuf);
 101                         return ret;
 102         } else {
 103                 if (copy_from_user(&data, argp, sizeof(struct scu_ipc_data)))
 104                         return -EFAULT;
 105                 ret = scu_reg_access(cmd, &data);
 106                 if (ret < 0)
 107                         return ret;
 108                 if (copy_to_user(argp, &data, sizeof(struct scu_ipc_data)))
 109                         return -EFAULT;
 110                 return 0;
 111         }
 112 }
 113
 114 static const struct file_operations scu_ipc_fops = {
 115         .unlocked_ioctl = scu_ipc_ioctl,
 116 };
 117
 118 static int __init ipc_module_init(void)
 119 {
 120         return register_chrdev(0, "intel_mid_scu", &scu_ipc_fops);
 121 }
 122
 123 static void __exit ipc_module_exit(void)
 124 {
 125         unregister_chrdev(major, "intel_mid_scu");
 126 }
 127
 128 module_init(ipc_module_init);
 129 module_exit(ipc_module_exit);
 130
 131 MODULE_LICENSE("GPL v2");
 132 MODULE_DESCRIPTION("Utility driver for intel scu ipc");
 133 MODULE_AUTHOR("Sreedhara <sreedhara.ds@intel.com>");