Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 1 | /* |
| 2 | * drivers/char/watchdog/max63xx_wdt.c |
| 3 | * |
| 4 | * Driver for max63{69,70,71,72,73,74} watchdog timers |
| 5 | * |
| 6 | * Copyright (C) 2009 Marc Zyngier <maz@misterjones.org> |
| 7 | * |
| 8 | * This file is licensed under the terms of the GNU General Public |
| 9 | * License version 2. This program is licensed "as is" without any |
| 10 | * warranty of any kind, whether express or implied. |
| 11 | * |
| 12 | * This driver assumes the watchdog pins are memory mapped (as it is |
| 13 | * the case for the Arcom Zeus). Should it be connected over GPIOs or |
| 14 | * another interface, some abstraction will have to be introduced. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/moduleparam.h> |
| 19 | #include <linux/types.h> |
| 20 | #include <linux/kernel.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/miscdevice.h> |
| 23 | #include <linux/watchdog.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/bitops.h> |
| 26 | #include <linux/platform_device.h> |
| 27 | #include <linux/spinlock.h> |
| 28 | #include <linux/uaccess.h> |
| 29 | #include <linux/io.h> |
| 30 | #include <linux/device.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 31 | #include <linux/slab.h> |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 32 | |
| 33 | #define DEFAULT_HEARTBEAT 60 |
| 34 | #define MAX_HEARTBEAT 60 |
| 35 | |
| 36 | static int heartbeat = DEFAULT_HEARTBEAT; |
| 37 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 38 | |
| 39 | /* |
| 40 | * Memory mapping: a single byte, 3 first lower bits to select bit 3 |
| 41 | * to ping the watchdog. |
| 42 | */ |
| 43 | #define MAX6369_WDSET (7 << 0) |
Wim Van Sebroeck | 5f3b275 | 2011-02-23 20:04:38 +0000 | [diff] [blame] | 44 | #define MAX6369_WDI (1 << 3) |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 45 | |
| 46 | static DEFINE_SPINLOCK(io_lock); |
| 47 | |
| 48 | static unsigned long wdt_status; |
| 49 | #define WDT_IN_USE 0 |
| 50 | #define WDT_RUNNING 1 |
| 51 | #define WDT_OK_TO_CLOSE 2 |
| 52 | |
| 53 | static int nodelay; |
| 54 | static struct resource *wdt_mem; |
| 55 | static void __iomem *wdt_base; |
| 56 | static struct platform_device *max63xx_pdev; |
| 57 | |
| 58 | /* |
| 59 | * The timeout values used are actually the absolute minimum the chip |
| 60 | * offers. Typical values on my board are slightly over twice as long |
| 61 | * (10s setting ends up with a 25s timeout), and can be up to 3 times |
| 62 | * the nominal setting (according to the datasheet). So please take |
| 63 | * these values with a grain of salt. Same goes for the initial delay |
| 64 | * "feature". Only max6373/74 have a few settings without this initial |
| 65 | * delay (selected with the "nodelay" parameter). |
| 66 | * |
| 67 | * I also decided to remove from the tables any timeout smaller than a |
| 68 | * second, as it looked completly overkill... |
| 69 | */ |
| 70 | |
| 71 | /* Timeouts in second */ |
| 72 | struct max63xx_timeout { |
| 73 | u8 wdset; |
| 74 | u8 tdelay; |
| 75 | u8 twd; |
| 76 | }; |
| 77 | |
| 78 | static struct max63xx_timeout max6369_table[] = { |
| 79 | { 5, 1, 1 }, |
| 80 | { 6, 10, 10 }, |
| 81 | { 7, 60, 60 }, |
| 82 | { }, |
| 83 | }; |
| 84 | |
| 85 | static struct max63xx_timeout max6371_table[] = { |
| 86 | { 6, 60, 3 }, |
| 87 | { 7, 60, 60 }, |
| 88 | { }, |
| 89 | }; |
| 90 | |
| 91 | static struct max63xx_timeout max6373_table[] = { |
| 92 | { 2, 60, 1 }, |
| 93 | { 5, 0, 1 }, |
| 94 | { 1, 3, 3 }, |
| 95 | { 7, 60, 10 }, |
| 96 | { 6, 0, 10 }, |
| 97 | { }, |
| 98 | }; |
| 99 | |
| 100 | static struct max63xx_timeout *current_timeout; |
| 101 | |
| 102 | static struct max63xx_timeout * |
| 103 | max63xx_select_timeout(struct max63xx_timeout *table, int value) |
| 104 | { |
| 105 | while (table->twd) { |
| 106 | if (value <= table->twd) { |
| 107 | if (nodelay && table->tdelay == 0) |
| 108 | return table; |
| 109 | |
| 110 | if (!nodelay) |
| 111 | return table; |
| 112 | } |
| 113 | |
| 114 | table++; |
| 115 | } |
| 116 | |
| 117 | return NULL; |
| 118 | } |
| 119 | |
| 120 | static void max63xx_wdt_ping(void) |
| 121 | { |
| 122 | u8 val; |
| 123 | |
| 124 | spin_lock(&io_lock); |
| 125 | |
| 126 | val = __raw_readb(wdt_base); |
| 127 | |
| 128 | __raw_writeb(val | MAX6369_WDI, wdt_base); |
| 129 | __raw_writeb(val & ~MAX6369_WDI, wdt_base); |
| 130 | |
| 131 | spin_unlock(&io_lock); |
| 132 | } |
| 133 | |
| 134 | static void max63xx_wdt_enable(struct max63xx_timeout *entry) |
| 135 | { |
| 136 | u8 val; |
| 137 | |
| 138 | if (test_and_set_bit(WDT_RUNNING, &wdt_status)) |
| 139 | return; |
| 140 | |
| 141 | spin_lock(&io_lock); |
| 142 | |
| 143 | val = __raw_readb(wdt_base); |
| 144 | val &= ~MAX6369_WDSET; |
| 145 | val |= entry->wdset; |
| 146 | __raw_writeb(val, wdt_base); |
| 147 | |
| 148 | spin_unlock(&io_lock); |
| 149 | |
| 150 | /* check for a edge triggered startup */ |
| 151 | if (entry->tdelay == 0) |
| 152 | max63xx_wdt_ping(); |
| 153 | } |
| 154 | |
| 155 | static void max63xx_wdt_disable(void) |
| 156 | { |
Marc Zyngier | b1183e0 | 2010-04-09 17:43:33 +0100 | [diff] [blame] | 157 | u8 val; |
| 158 | |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 159 | spin_lock(&io_lock); |
| 160 | |
Marc Zyngier | b1183e0 | 2010-04-09 17:43:33 +0100 | [diff] [blame] | 161 | val = __raw_readb(wdt_base); |
| 162 | val &= ~MAX6369_WDSET; |
| 163 | val |= 3; |
| 164 | __raw_writeb(val, wdt_base); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 165 | |
| 166 | spin_unlock(&io_lock); |
| 167 | |
| 168 | clear_bit(WDT_RUNNING, &wdt_status); |
| 169 | } |
| 170 | |
| 171 | static int max63xx_wdt_open(struct inode *inode, struct file *file) |
| 172 | { |
| 173 | if (test_and_set_bit(WDT_IN_USE, &wdt_status)) |
| 174 | return -EBUSY; |
| 175 | |
| 176 | max63xx_wdt_enable(current_timeout); |
| 177 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 178 | |
| 179 | return nonseekable_open(inode, file); |
| 180 | } |
| 181 | |
| 182 | static ssize_t max63xx_wdt_write(struct file *file, const char *data, |
| 183 | size_t len, loff_t *ppos) |
| 184 | { |
| 185 | if (len) { |
| 186 | if (!nowayout) { |
| 187 | size_t i; |
| 188 | |
| 189 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 190 | for (i = 0; i != len; i++) { |
| 191 | char c; |
| 192 | |
| 193 | if (get_user(c, data + i)) |
| 194 | return -EFAULT; |
| 195 | |
| 196 | if (c == 'V') |
| 197 | set_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 198 | } |
| 199 | } |
| 200 | |
| 201 | max63xx_wdt_ping(); |
| 202 | } |
| 203 | |
| 204 | return len; |
| 205 | } |
| 206 | |
| 207 | static const struct watchdog_info ident = { |
| 208 | .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING, |
| 209 | .identity = "max63xx Watchdog", |
| 210 | }; |
| 211 | |
| 212 | static long max63xx_wdt_ioctl(struct file *file, unsigned int cmd, |
| 213 | unsigned long arg) |
| 214 | { |
| 215 | int ret = -ENOTTY; |
| 216 | |
| 217 | switch (cmd) { |
| 218 | case WDIOC_GETSUPPORT: |
| 219 | ret = copy_to_user((struct watchdog_info *)arg, &ident, |
| 220 | sizeof(ident)) ? -EFAULT : 0; |
| 221 | break; |
| 222 | |
| 223 | case WDIOC_GETSTATUS: |
| 224 | case WDIOC_GETBOOTSTATUS: |
| 225 | ret = put_user(0, (int *)arg); |
| 226 | break; |
| 227 | |
| 228 | case WDIOC_KEEPALIVE: |
| 229 | max63xx_wdt_ping(); |
| 230 | ret = 0; |
| 231 | break; |
| 232 | |
| 233 | case WDIOC_GETTIMEOUT: |
| 234 | ret = put_user(heartbeat, (int *)arg); |
| 235 | break; |
| 236 | } |
| 237 | return ret; |
| 238 | } |
| 239 | |
| 240 | static int max63xx_wdt_release(struct inode *inode, struct file *file) |
| 241 | { |
| 242 | if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) |
| 243 | max63xx_wdt_disable(); |
| 244 | else |
| 245 | dev_crit(&max63xx_pdev->dev, |
| 246 | "device closed unexpectedly - timer will not stop\n"); |
| 247 | |
| 248 | clear_bit(WDT_IN_USE, &wdt_status); |
| 249 | clear_bit(WDT_OK_TO_CLOSE, &wdt_status); |
| 250 | |
| 251 | return 0; |
| 252 | } |
| 253 | |
| 254 | static const struct file_operations max63xx_wdt_fops = { |
| 255 | .owner = THIS_MODULE, |
| 256 | .llseek = no_llseek, |
| 257 | .write = max63xx_wdt_write, |
| 258 | .unlocked_ioctl = max63xx_wdt_ioctl, |
| 259 | .open = max63xx_wdt_open, |
| 260 | .release = max63xx_wdt_release, |
| 261 | }; |
| 262 | |
| 263 | static struct miscdevice max63xx_wdt_miscdev = { |
| 264 | .minor = WATCHDOG_MINOR, |
| 265 | .name = "watchdog", |
| 266 | .fops = &max63xx_wdt_fops, |
| 267 | }; |
| 268 | |
| 269 | static int __devinit max63xx_wdt_probe(struct platform_device *pdev) |
| 270 | { |
| 271 | int ret = 0; |
| 272 | int size; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 273 | struct device *dev = &pdev->dev; |
| 274 | struct max63xx_timeout *table; |
| 275 | |
| 276 | table = (struct max63xx_timeout *)pdev->id_entry->driver_data; |
| 277 | |
| 278 | if (heartbeat < 1 || heartbeat > MAX_HEARTBEAT) |
| 279 | heartbeat = DEFAULT_HEARTBEAT; |
| 280 | |
| 281 | dev_info(dev, "requesting %ds heartbeat\n", heartbeat); |
| 282 | current_timeout = max63xx_select_timeout(table, heartbeat); |
| 283 | |
| 284 | if (!current_timeout) { |
| 285 | dev_err(dev, "unable to satisfy heartbeat request\n"); |
| 286 | return -EINVAL; |
| 287 | } |
| 288 | |
| 289 | dev_info(dev, "using %ds heartbeat with %ds initial delay\n", |
| 290 | current_timeout->twd, current_timeout->tdelay); |
| 291 | |
| 292 | heartbeat = current_timeout->twd; |
| 293 | |
| 294 | max63xx_pdev = pdev; |
| 295 | |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 296 | wdt_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 297 | if (wdt_mem == NULL) { |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 298 | dev_err(dev, "failed to get memory region resource\n"); |
| 299 | return -ENOENT; |
| 300 | } |
| 301 | |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 302 | size = resource_size(wdt_mem); |
| 303 | if (!request_mem_region(wdt_mem->start, size, pdev->name)) { |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 304 | dev_err(dev, "failed to get memory region\n"); |
| 305 | return -ENOENT; |
| 306 | } |
| 307 | |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 308 | wdt_base = ioremap(wdt_mem->start, size); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 309 | if (!wdt_base) { |
| 310 | dev_err(dev, "failed to map memory region\n"); |
| 311 | ret = -ENOMEM; |
| 312 | goto out_request; |
| 313 | } |
| 314 | |
| 315 | ret = misc_register(&max63xx_wdt_miscdev); |
| 316 | if (ret < 0) { |
| 317 | dev_err(dev, "cannot register misc device\n"); |
| 318 | goto out_unmap; |
| 319 | } |
| 320 | |
| 321 | return 0; |
| 322 | |
| 323 | out_unmap: |
| 324 | iounmap(wdt_base); |
| 325 | out_request: |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 326 | release_mem_region(wdt_mem->start, size); |
| 327 | wdt_mem = NULL; |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 328 | |
| 329 | return ret; |
| 330 | } |
| 331 | |
| 332 | static int __devexit max63xx_wdt_remove(struct platform_device *pdev) |
| 333 | { |
| 334 | misc_deregister(&max63xx_wdt_miscdev); |
| 335 | if (wdt_mem) { |
Julia Lawall | f712eac | 2011-02-26 17:34:39 +0100 | [diff] [blame] | 336 | release_mem_region(wdt_mem->start, resource_size(wdt_mem)); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 337 | wdt_mem = NULL; |
| 338 | } |
| 339 | |
| 340 | if (wdt_base) |
| 341 | iounmap(wdt_base); |
| 342 | |
| 343 | return 0; |
| 344 | } |
| 345 | |
| 346 | static struct platform_device_id max63xx_id_table[] = { |
| 347 | { "max6369_wdt", (kernel_ulong_t)max6369_table, }, |
| 348 | { "max6370_wdt", (kernel_ulong_t)max6369_table, }, |
| 349 | { "max6371_wdt", (kernel_ulong_t)max6371_table, }, |
| 350 | { "max6372_wdt", (kernel_ulong_t)max6371_table, }, |
| 351 | { "max6373_wdt", (kernel_ulong_t)max6373_table, }, |
| 352 | { "max6374_wdt", (kernel_ulong_t)max6373_table, }, |
| 353 | { }, |
| 354 | }; |
| 355 | MODULE_DEVICE_TABLE(platform, max63xx_id_table); |
| 356 | |
| 357 | static struct platform_driver max63xx_wdt_driver = { |
| 358 | .probe = max63xx_wdt_probe, |
| 359 | .remove = __devexit_p(max63xx_wdt_remove), |
| 360 | .id_table = max63xx_id_table, |
| 361 | .driver = { |
| 362 | .name = "max63xx_wdt", |
| 363 | .owner = THIS_MODULE, |
| 364 | }, |
| 365 | }; |
| 366 | |
Axel Lin | b8ec611 | 2011-11-29 13:56:27 +0800 | [diff] [blame^] | 367 | module_platform_driver(max63xx_wdt_driver); |
Marc Zyngier | 66aaa7a | 2010-02-04 20:08:56 +0000 | [diff] [blame] | 368 | |
| 369 | MODULE_AUTHOR("Marc Zyngier <maz@misterjones.org>"); |
| 370 | MODULE_DESCRIPTION("max63xx Watchdog Driver"); |
| 371 | |
| 372 | module_param(heartbeat, int, 0); |
| 373 | MODULE_PARM_DESC(heartbeat, |
| 374 | "Watchdog heartbeat period in seconds from 1 to " |
| 375 | __MODULE_STRING(MAX_HEARTBEAT) ", default " |
| 376 | __MODULE_STRING(DEFAULT_HEARTBEAT)); |
| 377 | |
| 378 | module_param(nowayout, int, 0); |
| 379 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" |
| 380 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 381 | |
| 382 | module_param(nodelay, int, 0); |
| 383 | MODULE_PARM_DESC(nodelay, |
| 384 | "Force selection of a timeout setting without initial delay " |
| 385 | "(max6373/74 only, default=0)"); |
| 386 | |
| 387 | MODULE_LICENSE("GPL"); |
| 388 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |