tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Blackfin On-Chip OTP Memory Interface
3 * Supports BF52x/BF54x
4 *
5 * Copyright 2007-2008 Analog Devices Inc.
6 *
7 * Enter bugs at http://blackfin.uclinux.org/
8 *
9 * Licensed under the GPL-2 or later.
10 */
11
12#include <linux/device.h>
13#include <linux/errno.h>
14#include <linux/fs.h>
15#include <linux/init.h>
16#include <linux/miscdevice.h>
17#include <linux/module.h>
18#include <linux/mutex.h>
19#include <linux/types.h>
20
21#include <asm/blackfin.h>
22#include <asm/uaccess.h>
23
24#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
25#define stampit() stamp("here i am")
26#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
27
28#define DRIVER_NAME "bfin-otp"
29#define PFX DRIVER_NAME ": "
30
31static DEFINE_MUTEX(bfin_otp_lock);
32
33/* OTP Boot ROM functions */
34#define _BOOTROM_OTP_COMMAND 0xEF000018
35#define _BOOTROM_OTP_READ 0xEF00001A
36#define _BOOTROM_OTP_WRITE 0xEF00001C
37
38static u32 (* const otp_command)(u32 command, u32 value) = (void *)_BOOTROM_OTP_COMMAND;
39static u32 (* const otp_read)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_READ;
40static u32 (* const otp_write)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_WRITE;
41
42/* otp_command(): defines for "command" */
43#define OTP_INIT 0x00000001
44#define OTP_CLOSE 0x00000002
45
46/* otp_{read,write}(): defines for "flags" */
47#define OTP_LOWER_HALF 0x00000000 /* select upper/lower 64-bit half (bit 0) */
48#define OTP_UPPER_HALF 0x00000001
49#define OTP_NO_ECC 0x00000010 /* do not use ECC */
50#define OTP_LOCK 0x00000020 /* sets page protection bit for page */
51#define OTP_ACCESS_READ 0x00001000
52#define OTP_ACCESS_READWRITE 0x00002000
53
54/* Return values for all functions */
55#define OTP_SUCCESS 0x00000000
56#define OTP_MASTER_ERROR 0x001
57#define OTP_WRITE_ERROR 0x003
58#define OTP_READ_ERROR 0x005
59#define OTP_ACC_VIO_ERROR 0x009
60#define OTP_DATA_MULT_ERROR 0x011
61#define OTP_ECC_MULT_ERROR 0x021
62#define OTP_PREV_WR_ERROR 0x041
63#define OTP_DATA_SB_WARN 0x100
64#define OTP_ECC_SB_WARN 0x200
65
66/**
67 * bfin_otp_read - Read OTP pages
68 *
69 * All reads must be in half page chunks (half page == 64 bits).
70 */
71static ssize_t bfin_otp_read(struct file *file, char __user *buff, size_t count, loff_t *pos)
72{
73 ssize_t bytes_done;
74 u32 page, flags, ret;
75 u64 content;
76
77 stampit();
78
79 if (count % sizeof(u64))
80 return -EMSGSIZE;
81
82 if (mutex_lock_interruptible(&bfin_otp_lock))
83 return -ERESTARTSYS;
84
85 bytes_done = 0;
86 page = *pos / (sizeof(u64) * 2);
87 while (bytes_done < count) {
88 flags = (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF);
89 stamp("processing page %i (%s)", page, (flags == OTP_UPPER_HALF ? "upper" : "lower"));
90 ret = otp_read(page, flags, &content);
91 if (ret & OTP_MASTER_ERROR) {
92 bytes_done = -EIO;
93 break;
94 }
95 if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
96 bytes_done = -EFAULT;
97 break;
98 }
99 if (flags == OTP_UPPER_HALF)
100 ++page;
101 bytes_done += sizeof(content);
102 *pos += sizeof(content);
103 }
104
105 mutex_unlock(&bfin_otp_lock);
106
107 return bytes_done;
108}
109
110#ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
111/**
112 * bfin_otp_write - Write OTP pages
113 *
114 * All writes must be in half page chunks (half page == 64 bits).
115 */
116static ssize_t bfin_otp_write(struct file *filp, const char __user *buff, size_t count, loff_t *pos)
117{
118 stampit();
119
120 if (count % sizeof(u64))
121 return -EMSGSIZE;
122
123 if (mutex_lock_interruptible(&bfin_otp_lock))
124 return -ERESTARTSYS;
125
126 /* need otp_init() documentation before this can be implemented */
127
128 mutex_unlock(&bfin_otp_lock);
129
130 return -EINVAL;
131}
132#else
133# define bfin_otp_write NULL
134#endif
135
136static struct file_operations bfin_otp_fops = {
137 .owner = THIS_MODULE,
138 .read = bfin_otp_read,
139 .write = bfin_otp_write,
140};
141
142static struct miscdevice bfin_otp_misc_device = {
143 .minor = MISC_DYNAMIC_MINOR,
144 .name = DRIVER_NAME,
145 .fops = &bfin_otp_fops,
146};
147
148/**
149 * bfin_otp_init - Initialize module
150 *
151 * Registers the device and notifier handler. Actual device
152 * initialization is handled by bfin_otp_open().
153 */
154static int __init bfin_otp_init(void)
155{
156 int ret;
157
158 stampit();
159
160 ret = misc_register(&bfin_otp_misc_device);
161 if (ret) {
162 pr_init(KERN_ERR PFX "unable to register a misc device\n");
163 return ret;
164 }
165
166 pr_init(KERN_INFO PFX "initialized\n");
167
168 return 0;
169}
170
171/**
172 * bfin_otp_exit - Deinitialize module
173 *
174 * Unregisters the device and notifier handler. Actual device
175 * deinitialization is handled by bfin_otp_close().
176 */
177static void __exit bfin_otp_exit(void)
178{
179 stampit();
180
181 misc_deregister(&bfin_otp_misc_device);
182}
183
184module_init(bfin_otp_init);
185module_exit(bfin_otp_exit);
186
187MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
188MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
189MODULE_LICENSE("GPL");