Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Blackfin On-Chip OTP Memory Interface |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 3 | * |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 4 | * Copyright 2007-2009 Analog Devices Inc. |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 5 | * |
| 6 | * Enter bugs at http://blackfin.uclinux.org/ |
| 7 | * |
| 8 | * Licensed under the GPL-2 or later. |
| 9 | */ |
| 10 | |
| 11 | #include <linux/device.h> |
| 12 | #include <linux/errno.h> |
| 13 | #include <linux/fs.h> |
| 14 | #include <linux/init.h> |
| 15 | #include <linux/miscdevice.h> |
| 16 | #include <linux/module.h> |
| 17 | #include <linux/mutex.h> |
| 18 | #include <linux/types.h> |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 19 | #include <mtd/mtd-abi.h> |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 20 | |
| 21 | #include <asm/blackfin.h> |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 22 | #include <asm/bfrom.h> |
Linus Torvalds | 7c0f6ba | 2016-12-24 11:46:01 -0800 | [diff] [blame] | 23 | #include <linux/uaccess.h> |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 24 | |
| 25 | #define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) |
| 26 | #define stampit() stamp("here i am") |
| 27 | #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); }) |
| 28 | |
| 29 | #define DRIVER_NAME "bfin-otp" |
| 30 | #define PFX DRIVER_NAME ": " |
| 31 | |
| 32 | static DEFINE_MUTEX(bfin_otp_lock); |
| 33 | |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 34 | /** |
| 35 | * bfin_otp_read - Read OTP pages |
| 36 | * |
| 37 | * All reads must be in half page chunks (half page == 64 bits). |
| 38 | */ |
| 39 | static ssize_t bfin_otp_read(struct file *file, char __user *buff, size_t count, loff_t *pos) |
| 40 | { |
| 41 | ssize_t bytes_done; |
| 42 | u32 page, flags, ret; |
| 43 | u64 content; |
| 44 | |
| 45 | stampit(); |
| 46 | |
| 47 | if (count % sizeof(u64)) |
| 48 | return -EMSGSIZE; |
| 49 | |
| 50 | if (mutex_lock_interruptible(&bfin_otp_lock)) |
| 51 | return -ERESTARTSYS; |
| 52 | |
| 53 | bytes_done = 0; |
| 54 | page = *pos / (sizeof(u64) * 2); |
| 55 | while (bytes_done < count) { |
| 56 | flags = (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF); |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 57 | stamp("processing page %i (0x%x:%s)", page, flags, |
| 58 | (flags & OTP_UPPER_HALF ? "upper" : "lower")); |
| 59 | ret = bfrom_OtpRead(page, flags, &content); |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 60 | if (ret & OTP_MASTER_ERROR) { |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 61 | stamp("error from otp: 0x%x", ret); |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 62 | bytes_done = -EIO; |
| 63 | break; |
| 64 | } |
| 65 | if (copy_to_user(buff + bytes_done, &content, sizeof(content))) { |
| 66 | bytes_done = -EFAULT; |
| 67 | break; |
| 68 | } |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 69 | if (flags & OTP_UPPER_HALF) |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 70 | ++page; |
| 71 | bytes_done += sizeof(content); |
| 72 | *pos += sizeof(content); |
| 73 | } |
| 74 | |
| 75 | mutex_unlock(&bfin_otp_lock); |
| 76 | |
| 77 | return bytes_done; |
| 78 | } |
| 79 | |
| 80 | #ifdef CONFIG_BFIN_OTP_WRITE_ENABLE |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 81 | static bool allow_writes; |
| 82 | |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 83 | /** |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 84 | * bfin_otp_init_timing - setup OTP timing parameters |
| 85 | * |
| 86 | * Required before doing any write operation. Algorithms from HRM. |
| 87 | */ |
| 88 | static u32 bfin_otp_init_timing(void) |
| 89 | { |
| 90 | u32 tp1, tp2, tp3, timing; |
| 91 | |
| 92 | tp1 = get_sclk() / 1000000; |
| 93 | tp2 = (2 * get_sclk() / 10000000) << 8; |
| 94 | tp3 = (0x1401) << 15; |
| 95 | timing = tp1 | tp2 | tp3; |
| 96 | if (bfrom_OtpCommand(OTP_INIT, timing)) |
| 97 | return 0; |
| 98 | |
| 99 | return timing; |
| 100 | } |
| 101 | |
| 102 | /** |
| 103 | * bfin_otp_deinit_timing - set timings to only allow reads |
| 104 | * |
| 105 | * Should be called after all writes are done. |
| 106 | */ |
| 107 | static void bfin_otp_deinit_timing(u32 timing) |
| 108 | { |
| 109 | /* mask bits [31:15] so that any attempts to write fail */ |
| 110 | bfrom_OtpCommand(OTP_CLOSE, 0); |
| 111 | bfrom_OtpCommand(OTP_INIT, timing & ~(-1 << 15)); |
| 112 | bfrom_OtpCommand(OTP_CLOSE, 0); |
| 113 | } |
| 114 | |
| 115 | /** |
| 116 | * bfin_otp_write - write OTP pages |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 117 | * |
| 118 | * All writes must be in half page chunks (half page == 64 bits). |
| 119 | */ |
| 120 | static ssize_t bfin_otp_write(struct file *filp, const char __user *buff, size_t count, loff_t *pos) |
| 121 | { |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 122 | ssize_t bytes_done; |
| 123 | u32 timing, page, base_flags, flags, ret; |
| 124 | u64 content; |
| 125 | |
| 126 | if (!allow_writes) |
| 127 | return -EACCES; |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 128 | |
| 129 | if (count % sizeof(u64)) |
| 130 | return -EMSGSIZE; |
| 131 | |
| 132 | if (mutex_lock_interruptible(&bfin_otp_lock)) |
| 133 | return -ERESTARTSYS; |
| 134 | |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 135 | stampit(); |
| 136 | |
| 137 | timing = bfin_otp_init_timing(); |
| 138 | if (timing == 0) { |
| 139 | mutex_unlock(&bfin_otp_lock); |
| 140 | return -EIO; |
| 141 | } |
| 142 | |
| 143 | base_flags = OTP_CHECK_FOR_PREV_WRITE; |
| 144 | |
| 145 | bytes_done = 0; |
| 146 | page = *pos / (sizeof(u64) * 2); |
| 147 | while (bytes_done < count) { |
| 148 | flags = base_flags | (*pos % (sizeof(u64) * 2) ? OTP_UPPER_HALF : OTP_LOWER_HALF); |
| 149 | stamp("processing page %i (0x%x:%s) from %p", page, flags, |
| 150 | (flags & OTP_UPPER_HALF ? "upper" : "lower"), buff + bytes_done); |
| 151 | if (copy_from_user(&content, buff + bytes_done, sizeof(content))) { |
| 152 | bytes_done = -EFAULT; |
| 153 | break; |
| 154 | } |
| 155 | ret = bfrom_OtpWrite(page, flags, &content); |
| 156 | if (ret & OTP_MASTER_ERROR) { |
| 157 | stamp("error from otp: 0x%x", ret); |
| 158 | bytes_done = -EIO; |
| 159 | break; |
| 160 | } |
| 161 | if (flags & OTP_UPPER_HALF) |
| 162 | ++page; |
| 163 | bytes_done += sizeof(content); |
| 164 | *pos += sizeof(content); |
| 165 | } |
| 166 | |
| 167 | bfin_otp_deinit_timing(timing); |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 168 | |
| 169 | mutex_unlock(&bfin_otp_lock); |
| 170 | |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 171 | return bytes_done; |
| 172 | } |
| 173 | |
| 174 | static long bfin_otp_ioctl(struct file *filp, unsigned cmd, unsigned long arg) |
| 175 | { |
| 176 | stampit(); |
| 177 | |
| 178 | switch (cmd) { |
| 179 | case OTPLOCK: { |
| 180 | u32 timing; |
| 181 | int ret = -EIO; |
| 182 | |
| 183 | if (!allow_writes) |
| 184 | return -EACCES; |
| 185 | |
| 186 | if (mutex_lock_interruptible(&bfin_otp_lock)) |
| 187 | return -ERESTARTSYS; |
| 188 | |
| 189 | timing = bfin_otp_init_timing(); |
| 190 | if (timing) { |
| 191 | u32 otp_result = bfrom_OtpWrite(arg, OTP_LOCK, NULL); |
| 192 | stamp("locking page %lu resulted in 0x%x", arg, otp_result); |
| 193 | if (!(otp_result & OTP_MASTER_ERROR)) |
| 194 | ret = 0; |
| 195 | |
| 196 | bfin_otp_deinit_timing(timing); |
| 197 | } |
| 198 | |
| 199 | mutex_unlock(&bfin_otp_lock); |
| 200 | |
| 201 | return ret; |
| 202 | } |
| 203 | |
| 204 | case MEMLOCK: |
| 205 | allow_writes = false; |
| 206 | return 0; |
| 207 | |
| 208 | case MEMUNLOCK: |
| 209 | allow_writes = true; |
| 210 | return 0; |
| 211 | } |
| 212 | |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 213 | return -EINVAL; |
| 214 | } |
| 215 | #else |
| 216 | # define bfin_otp_write NULL |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 217 | # define bfin_otp_ioctl NULL |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 218 | #endif |
| 219 | |
Alexey Dobriyan | 828c095 | 2009-10-01 15:43:56 -0700 | [diff] [blame] | 220 | static const struct file_operations bfin_otp_fops = { |
Mike Frysinger | 156dd63 | 2009-09-23 15:57:16 -0700 | [diff] [blame] | 221 | .owner = THIS_MODULE, |
| 222 | .unlocked_ioctl = bfin_otp_ioctl, |
| 223 | .read = bfin_otp_read, |
| 224 | .write = bfin_otp_write, |
Arnd Bergmann | 6038f37 | 2010-08-15 18:52:59 +0200 | [diff] [blame] | 225 | .llseek = default_llseek, |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 226 | }; |
| 227 | |
| 228 | static struct miscdevice bfin_otp_misc_device = { |
| 229 | .minor = MISC_DYNAMIC_MINOR, |
| 230 | .name = DRIVER_NAME, |
| 231 | .fops = &bfin_otp_fops, |
| 232 | }; |
PrasannaKumar Muralidharan | d6a38c0 | 2016-08-25 22:30:50 +0530 | [diff] [blame] | 233 | module_misc_device(bfin_otp_misc_device); |
Mike Frysinger | 2dc63a8 | 2008-04-25 08:04:56 +0800 | [diff] [blame] | 234 | |
| 235 | MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); |
| 236 | MODULE_DESCRIPTION("Blackfin OTP Memory Interface"); |
| 237 | MODULE_LICENSE("GPL"); |