2 * Blackfin On-Chip OTP Memory Interface
5 * Copyright 2007-2008 Analog Devices Inc.
7 * Enter bugs at http://blackfin.uclinux.org/
9 * Licensed under the GPL-2 or later.
12 #include <linux/device.h>
13 #include <linux/errno.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>
21 #include <asm/blackfin.h>
22 #include <asm/uaccess.h>
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); })
28 #define DRIVER_NAME "bfin-otp"
29 #define PFX DRIVER_NAME ": "
31 static DEFINE_MUTEX(bfin_otp_lock);
33 /* OTP Boot ROM functions */
34 #define _BOOTROM_OTP_COMMAND 0xEF000018
35 #define _BOOTROM_OTP_READ 0xEF00001A
36 #define _BOOTROM_OTP_WRITE 0xEF00001C
38 static u32 (* const otp_command)(u32 command, u32 value) = (void *)_BOOTROM_OTP_COMMAND;
39 static u32 (* const otp_read)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_READ;
40 static u32 (* const otp_write)(u32 page, u32 flags, u64 *page_content) = (void *)_BOOTROM_OTP_WRITE;
42 /* otp_command(): defines for "command" */
43 #define OTP_INIT 0x00000001
44 #define OTP_CLOSE 0x00000002
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
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
67 * bfin_otp_read - Read OTP pages
69 * All reads must be in half page chunks (half page == 64 bits).
71 static ssize_t bfin_otp_read(struct file *file, char __user *buff, size_t count, loff_t *pos)
79 if (count % sizeof(u64))
82 if (mutex_lock_interruptible(&bfin_otp_lock))
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) {
95 if (copy_to_user(buff + bytes_done, &content, sizeof(content))) {
99 if (flags == OTP_UPPER_HALF)
101 bytes_done += sizeof(content);
102 *pos += sizeof(content);
105 mutex_unlock(&bfin_otp_lock);
110 #ifdef CONFIG_BFIN_OTP_WRITE_ENABLE
112 * bfin_otp_write - Write OTP pages
114 * All writes must be in half page chunks (half page == 64 bits).
116 static ssize_t bfin_otp_write(struct file *filp, const char __user *buff, size_t count, loff_t *pos)
120 if (count % sizeof(u64))
123 if (mutex_lock_interruptible(&bfin_otp_lock))
126 /* need otp_init() documentation before this can be implemented */
128 mutex_unlock(&bfin_otp_lock);
133 # define bfin_otp_write NULL
136 static struct file_operations bfin_otp_fops = {
137 .owner = THIS_MODULE,
138 .read = bfin_otp_read,
139 .write = bfin_otp_write,
142 static struct miscdevice bfin_otp_misc_device = {
143 .minor = MISC_DYNAMIC_MINOR,
145 .fops = &bfin_otp_fops,
149 * bfin_otp_init - Initialize module
151 * Registers the device and notifier handler. Actual device
152 * initialization is handled by bfin_otp_open().
154 static int __init bfin_otp_init(void)
160 ret = misc_register(&bfin_otp_misc_device);
162 pr_init(KERN_ERR PFX "unable to register a misc device\n");
166 pr_init(KERN_INFO PFX "initialized\n");
172 * bfin_otp_exit - Deinitialize module
174 * Unregisters the device and notifier handler. Actual device
175 * deinitialization is handled by bfin_otp_close().
177 static void __exit bfin_otp_exit(void)
181 misc_deregister(&bfin_otp_misc_device);
184 module_init(bfin_otp_init);
185 module_exit(bfin_otp_exit);
187 MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
188 MODULE_DESCRIPTION("Blackfin OTP Memory Interface");
189 MODULE_LICENSE("GPL");