| 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 | |
| 31 | static 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 | |
| 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; |
| 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 | */ |
| 71 | static 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 | */ |
| 116 | static 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 | |
| 136 | static struct file_operations bfin_otp_fops = { |
| 137 | .owner = THIS_MODULE, |
| 138 | .read = bfin_otp_read, |
| 139 | .write = bfin_otp_write, |
| 140 | }; |
| 141 | |
| 142 | static 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 | */ |
| 154 | static 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 | */ |
| 177 | static void __exit bfin_otp_exit(void) |
| 178 | { |
| 179 | stampit(); |
| 180 | |
| 181 | misc_deregister(&bfin_otp_misc_device); |
| 182 | } |
| 183 | |
| 184 | module_init(bfin_otp_init); |
| 185 | module_exit(bfin_otp_exit); |
| 186 | |
| 187 | MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); |
| 188 | MODULE_DESCRIPTION("Blackfin OTP Memory Interface"); |
| 189 | MODULE_LICENSE("GPL"); |