Wan ZongShun | 0400e31 | 2009-08-17 18:00:01 +0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2009 Nuvoton technology corporation. |
| 3 | * |
| 4 | * Wan ZongShun <mcuos.com@gmail.com> |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License as published by |
| 8 | * the Free Software Foundation;version 2 of the License. |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | #include <linux/bitops.h> |
| 13 | #include <linux/errno.h> |
| 14 | #include <linux/fs.h> |
| 15 | #include <linux/init.h> |
| 16 | #include <linux/io.h> |
| 17 | #include <linux/clk.h> |
| 18 | #include <linux/kernel.h> |
| 19 | #include <linux/miscdevice.h> |
| 20 | #include <linux/module.h> |
| 21 | #include <linux/moduleparam.h> |
| 22 | #include <linux/platform_device.h> |
| 23 | #include <linux/interrupt.h> |
| 24 | #include <linux/types.h> |
| 25 | #include <linux/watchdog.h> |
| 26 | #include <linux/uaccess.h> |
| 27 | |
| 28 | #define REG_WTCR 0x1c |
| 29 | #define WTCLK (0x01 << 10) |
| 30 | #define WTE (0x01 << 7) /*wdt enable*/ |
| 31 | #define WTIS (0x03 << 4) |
| 32 | #define WTIF (0x01 << 3) |
| 33 | #define WTRF (0x01 << 2) |
| 34 | #define WTRE (0x01 << 1) |
| 35 | #define WTR (0x01 << 0) |
| 36 | /* |
| 37 | * The watchdog time interval can be calculated via following formula: |
| 38 | * WTIS real time interval (formula) |
| 39 | * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds |
| 40 | * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds |
| 41 | * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds |
| 42 | * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds |
| 43 | * |
| 44 | * The external crystal freq is 15Mhz in the nuc900 evaluation board. |
| 45 | * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, |
| 46 | * 0x03 = +- 16.92 seconds.. |
| 47 | */ |
| 48 | #define WDT_HW_TIMEOUT 0x02 |
| 49 | #define WDT_TIMEOUT (HZ/2) |
| 50 | #define WDT_HEARTBEAT 15 |
| 51 | |
| 52 | static int heartbeat = WDT_HEARTBEAT; |
| 53 | module_param(heartbeat, int, 0); |
| 54 | MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " |
| 55 | "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); |
| 56 | |
| 57 | static int nowayout = WATCHDOG_NOWAYOUT; |
| 58 | module_param(nowayout, int, 0); |
| 59 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " |
| 60 | "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |
| 61 | |
| 62 | struct nuc900_wdt { |
| 63 | struct resource *res; |
| 64 | struct clk *wdt_clock; |
| 65 | struct platform_device *pdev; |
| 66 | void __iomem *wdt_base; |
| 67 | char expect_close; |
| 68 | struct timer_list timer; |
| 69 | spinlock_t wdt_lock; |
| 70 | unsigned long next_heartbeat; |
| 71 | }; |
| 72 | |
| 73 | static unsigned long nuc900wdt_busy; |
| 74 | struct nuc900_wdt *nuc900_wdt; |
| 75 | |
| 76 | static inline void nuc900_wdt_keepalive(void) |
| 77 | { |
| 78 | unsigned int val; |
| 79 | |
| 80 | spin_lock(&nuc900_wdt->wdt_lock); |
| 81 | |
| 82 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
| 83 | val |= (WTR | WTIF); |
| 84 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
| 85 | |
| 86 | spin_unlock(&nuc900_wdt->wdt_lock); |
| 87 | } |
| 88 | |
| 89 | static inline void nuc900_wdt_start(void) |
| 90 | { |
| 91 | unsigned int val; |
| 92 | |
| 93 | spin_lock(&nuc900_wdt->wdt_lock); |
| 94 | |
| 95 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
| 96 | val |= (WTRE | WTE | WTR | WTCLK | WTIF); |
| 97 | val &= ~WTIS; |
| 98 | val |= (WDT_HW_TIMEOUT << 0x04); |
| 99 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
| 100 | |
| 101 | spin_unlock(&nuc900_wdt->wdt_lock); |
| 102 | |
| 103 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; |
| 104 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); |
| 105 | } |
| 106 | |
| 107 | static inline void nuc900_wdt_stop(void) |
| 108 | { |
| 109 | unsigned int val; |
| 110 | |
| 111 | del_timer(&nuc900_wdt->timer); |
| 112 | |
| 113 | spin_lock(&nuc900_wdt->wdt_lock); |
| 114 | |
| 115 | val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); |
| 116 | val &= ~WTE; |
| 117 | __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); |
| 118 | |
| 119 | spin_unlock(&nuc900_wdt->wdt_lock); |
| 120 | } |
| 121 | |
| 122 | static inline void nuc900_wdt_ping(void) |
| 123 | { |
| 124 | nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; |
| 125 | } |
| 126 | |
| 127 | static int nuc900_wdt_open(struct inode *inode, struct file *file) |
| 128 | { |
| 129 | |
| 130 | if (test_and_set_bit(0, &nuc900wdt_busy)) |
| 131 | return -EBUSY; |
| 132 | |
| 133 | nuc900_wdt_start(); |
| 134 | |
| 135 | return nonseekable_open(inode, file); |
| 136 | } |
| 137 | |
| 138 | static int nuc900_wdt_close(struct inode *inode, struct file *file) |
| 139 | { |
| 140 | if (nuc900_wdt->expect_close == 42) |
| 141 | nuc900_wdt_stop(); |
| 142 | else { |
| 143 | dev_crit(&nuc900_wdt->pdev->dev, |
| 144 | "Unexpected close, not stopping watchdog!\n"); |
| 145 | nuc900_wdt_ping(); |
| 146 | } |
| 147 | |
| 148 | nuc900_wdt->expect_close = 0; |
| 149 | clear_bit(0, &nuc900wdt_busy); |
| 150 | return 0; |
| 151 | } |
| 152 | |
| 153 | static const struct watchdog_info nuc900_wdt_info = { |
| 154 | .identity = "nuc900 watchdog", |
| 155 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | |
| 156 | WDIOF_MAGICCLOSE, |
| 157 | }; |
| 158 | |
| 159 | static long nuc900_wdt_ioctl(struct file *file, |
| 160 | unsigned int cmd, unsigned long arg) |
| 161 | { |
| 162 | void __user *argp = (void __user *)arg; |
| 163 | int __user *p = argp; |
| 164 | int new_value; |
| 165 | |
| 166 | switch (cmd) { |
| 167 | case WDIOC_GETSUPPORT: |
| 168 | return copy_to_user(argp, &nuc900_wdt_info, |
| 169 | sizeof(nuc900_wdt_info)) ? -EFAULT : 0; |
| 170 | case WDIOC_GETSTATUS: |
| 171 | case WDIOC_GETBOOTSTATUS: |
| 172 | return put_user(0, p); |
| 173 | |
| 174 | case WDIOC_KEEPALIVE: |
| 175 | nuc900_wdt_ping(); |
| 176 | return 0; |
| 177 | |
| 178 | case WDIOC_SETTIMEOUT: |
| 179 | if (get_user(new_value, p)) |
| 180 | return -EFAULT; |
| 181 | |
| 182 | heartbeat = new_value; |
| 183 | nuc900_wdt_ping(); |
| 184 | |
| 185 | return put_user(new_value, p); |
| 186 | case WDIOC_GETTIMEOUT: |
| 187 | return put_user(heartbeat, p); |
| 188 | default: |
| 189 | return -ENOTTY; |
| 190 | } |
| 191 | } |
| 192 | |
| 193 | static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, |
| 194 | size_t len, loff_t *ppos) |
| 195 | { |
| 196 | if (!len) |
| 197 | return 0; |
| 198 | |
| 199 | /* Scan for magic character */ |
| 200 | if (!nowayout) { |
| 201 | size_t i; |
| 202 | |
| 203 | nuc900_wdt->expect_close = 0; |
| 204 | |
| 205 | for (i = 0; i < len; i++) { |
| 206 | char c; |
| 207 | if (get_user(c, data + i)) |
| 208 | return -EFAULT; |
| 209 | if (c == 'V') { |
| 210 | nuc900_wdt->expect_close = 42; |
| 211 | break; |
| 212 | } |
| 213 | } |
| 214 | } |
| 215 | |
| 216 | nuc900_wdt_ping(); |
| 217 | return len; |
| 218 | } |
| 219 | |
| 220 | static void nuc900_wdt_timer_ping(unsigned long data) |
| 221 | { |
| 222 | if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { |
| 223 | nuc900_wdt_keepalive(); |
| 224 | mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); |
| 225 | } else |
| 226 | dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); |
| 227 | } |
| 228 | |
| 229 | static const struct file_operations nuc900wdt_fops = { |
| 230 | .owner = THIS_MODULE, |
| 231 | .llseek = no_llseek, |
| 232 | .unlocked_ioctl = nuc900_wdt_ioctl, |
| 233 | .open = nuc900_wdt_open, |
| 234 | .release = nuc900_wdt_close, |
| 235 | .write = nuc900_wdt_write, |
| 236 | }; |
| 237 | |
| 238 | static struct miscdevice nuc900wdt_miscdev = { |
| 239 | .minor = WATCHDOG_MINOR, |
| 240 | .name = "watchdog", |
| 241 | .fops = &nuc900wdt_fops, |
| 242 | }; |
| 243 | |
| 244 | static int __devinit nuc900wdt_probe(struct platform_device *pdev) |
| 245 | { |
| 246 | int ret = 0; |
| 247 | |
| 248 | nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL); |
| 249 | if (!nuc900_wdt) |
| 250 | return -ENOMEM; |
| 251 | |
| 252 | nuc900_wdt->pdev = pdev; |
| 253 | |
| 254 | spin_lock_init(&nuc900_wdt->wdt_lock); |
| 255 | |
| 256 | nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 257 | if (nuc900_wdt->res == NULL) { |
| 258 | dev_err(&pdev->dev, "no memory resource specified\n"); |
| 259 | ret = -ENOENT; |
| 260 | goto err_get; |
| 261 | } |
| 262 | |
| 263 | if (!request_mem_region(nuc900_wdt->res->start, |
| 264 | resource_size(nuc900_wdt->res), pdev->name)) { |
| 265 | dev_err(&pdev->dev, "failed to get memory region\n"); |
| 266 | ret = -ENOENT; |
| 267 | goto err_get; |
| 268 | } |
| 269 | |
| 270 | nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start, |
| 271 | resource_size(nuc900_wdt->res)); |
| 272 | if (nuc900_wdt->wdt_base == NULL) { |
| 273 | dev_err(&pdev->dev, "failed to ioremap() region\n"); |
| 274 | ret = -EINVAL; |
| 275 | goto err_req; |
| 276 | } |
| 277 | |
| 278 | nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL); |
| 279 | if (IS_ERR(nuc900_wdt->wdt_clock)) { |
| 280 | dev_err(&pdev->dev, "failed to find watchdog clock source\n"); |
| 281 | ret = PTR_ERR(nuc900_wdt->wdt_clock); |
| 282 | goto err_map; |
| 283 | } |
| 284 | |
| 285 | clk_enable(nuc900_wdt->wdt_clock); |
| 286 | |
| 287 | setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); |
| 288 | |
| 289 | if (misc_register(&nuc900wdt_miscdev)) { |
| 290 | dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", |
| 291 | WATCHDOG_MINOR, ret); |
| 292 | goto err_clk; |
| 293 | } |
| 294 | |
| 295 | return 0; |
| 296 | |
| 297 | err_clk: |
| 298 | clk_disable(nuc900_wdt->wdt_clock); |
| 299 | clk_put(nuc900_wdt->wdt_clock); |
| 300 | err_map: |
| 301 | iounmap(nuc900_wdt->wdt_base); |
| 302 | err_req: |
| 303 | release_mem_region(nuc900_wdt->res->start, |
| 304 | resource_size(nuc900_wdt->res)); |
| 305 | err_get: |
| 306 | kfree(nuc900_wdt); |
| 307 | return ret; |
| 308 | } |
| 309 | |
| 310 | static int __devexit nuc900wdt_remove(struct platform_device *pdev) |
| 311 | { |
| 312 | misc_deregister(&nuc900wdt_miscdev); |
| 313 | |
| 314 | clk_disable(nuc900_wdt->wdt_clock); |
| 315 | clk_put(nuc900_wdt->wdt_clock); |
| 316 | |
| 317 | iounmap(nuc900_wdt->wdt_base); |
| 318 | |
| 319 | release_mem_region(nuc900_wdt->res->start, |
| 320 | resource_size(nuc900_wdt->res)); |
| 321 | |
| 322 | kfree(nuc900_wdt); |
| 323 | |
| 324 | return 0; |
| 325 | } |
| 326 | |
| 327 | static struct platform_driver nuc900wdt_driver = { |
| 328 | .probe = nuc900wdt_probe, |
| 329 | .remove = __devexit_p(nuc900wdt_remove), |
| 330 | .driver = { |
| 331 | .name = "nuc900-wdt", |
| 332 | .owner = THIS_MODULE, |
| 333 | }, |
| 334 | }; |
| 335 | |
| 336 | static int __init nuc900_wdt_init(void) |
| 337 | { |
| 338 | return platform_driver_register(&nuc900wdt_driver); |
| 339 | } |
| 340 | |
| 341 | static void __exit nuc900_wdt_exit(void) |
| 342 | { |
| 343 | platform_driver_unregister(&nuc900wdt_driver); |
| 344 | } |
| 345 | |
| 346 | module_init(nuc900_wdt_init); |
| 347 | module_exit(nuc900_wdt_exit); |
| 348 | |
| 349 | MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); |
| 350 | MODULE_DESCRIPTION("Watchdog driver for NUC900"); |
| 351 | MODULE_LICENSE("GPL"); |
| 352 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| 353 | MODULE_ALIAS("platform:nuc900-wdt"); |