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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>"); |