1 /* 2 * Atheros AR71XX/AR724X/AR913X built-in hardware watchdog timer. 3 * 4 * Copyright (C) 2008-2011 Gabor Juhos <juhosg@openwrt.org> 5 * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org> 6 * 7 * This driver was based on: drivers/watchdog/ixp4xx_wdt.c 8 * Author: Deepak Saxena <dsaxena@plexity.net> 9 * Copyright 2004 (c) MontaVista, Software, Inc. 10 * 11 * which again was based on sa1100 driver, 12 * Copyright (C) 2000 Oleg Drokin <green@crimea.edu> 13 * 14 * This program is free software; you can redistribute it and/or modify it 15 * under the terms of the GNU General Public License version 2 as published 16 * by the Free Software Foundation. 17 * 18 */ 19 20 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 21 22 #include <linux/bitops.h> 23 #include <linux/errno.h> 24 #include <linux/fs.h> 25 #include <linux/init.h> 26 #include <linux/io.h> 27 #include <linux/kernel.h> 28 #include <linux/miscdevice.h> 29 #include <linux/module.h> 30 #include <linux/moduleparam.h> 31 #include <linux/platform_device.h> 32 #include <linux/types.h> 33 #include <linux/watchdog.h> 34 #include <linux/clk.h> 35 #include <linux/err.h> 36 #include <linux/of.h> 37 #include <linux/of_platform.h> 38 39 #define DRIVER_NAME "ath79-wdt" 40 41 #define WDT_TIMEOUT 15 /* seconds */ 42 43 #define WDOG_REG_CTRL 0x00 44 #define WDOG_REG_TIMER 0x04 45 46 #define WDOG_CTRL_LAST_RESET BIT(31) 47 #define WDOG_CTRL_ACTION_MASK 3 48 #define WDOG_CTRL_ACTION_NONE 0 /* no action */ 49 #define WDOG_CTRL_ACTION_GPI 1 /* general purpose interrupt */ 50 #define WDOG_CTRL_ACTION_NMI 2 /* NMI */ 51 #define WDOG_CTRL_ACTION_FCR 3 /* full chip reset */ 52 53 static bool nowayout = WATCHDOG_NOWAYOUT; 54 module_param(nowayout, bool, 0); 55 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 56 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 57 58 static int timeout = WDT_TIMEOUT; 59 module_param(timeout, int, 0); 60 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds " 61 "(default=" __MODULE_STRING(WDT_TIMEOUT) "s)"); 62 63 static unsigned long wdt_flags; 64 65 #define WDT_FLAGS_BUSY 0 66 #define WDT_FLAGS_EXPECT_CLOSE 1 67 68 static struct clk *wdt_clk; 69 static unsigned long wdt_freq; 70 static int boot_status; 71 static int max_timeout; 72 static void __iomem *wdt_base; 73 74 static inline void ath79_wdt_wr(unsigned reg, u32 val) 75 { 76 iowrite32(val, wdt_base + reg); 77 } 78 79 static inline u32 ath79_wdt_rr(unsigned reg) 80 { 81 return ioread32(wdt_base + reg); 82 } 83 84 static inline void ath79_wdt_keepalive(void) 85 { 86 ath79_wdt_wr(WDOG_REG_TIMER, wdt_freq * timeout); 87 /* flush write */ 88 ath79_wdt_rr(WDOG_REG_TIMER); 89 } 90 91 static inline void ath79_wdt_enable(void) 92 { 93 ath79_wdt_keepalive(); 94 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_FCR); 95 /* flush write */ 96 ath79_wdt_rr(WDOG_REG_CTRL); 97 } 98 99 static inline void ath79_wdt_disable(void) 100 { 101 ath79_wdt_wr(WDOG_REG_CTRL, WDOG_CTRL_ACTION_NONE); 102 /* flush write */ 103 ath79_wdt_rr(WDOG_REG_CTRL); 104 } 105 106 static int ath79_wdt_set_timeout(int val) 107 { 108 if (val < 1 || val > max_timeout) 109 return -EINVAL; 110 111 timeout = val; 112 ath79_wdt_keepalive(); 113 114 return 0; 115 } 116 117 static int ath79_wdt_open(struct inode *inode, struct file *file) 118 { 119 if (test_and_set_bit(WDT_FLAGS_BUSY, &wdt_flags)) 120 return -EBUSY; 121 122 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); 123 ath79_wdt_enable(); 124 125 return nonseekable_open(inode, file); 126 } 127 128 static int ath79_wdt_release(struct inode *inode, struct file *file) 129 { 130 if (test_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags)) 131 ath79_wdt_disable(); 132 else { 133 pr_crit("device closed unexpectedly, watchdog timer will not stop!\n"); 134 ath79_wdt_keepalive(); 135 } 136 137 clear_bit(WDT_FLAGS_BUSY, &wdt_flags); 138 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); 139 140 return 0; 141 } 142 143 static ssize_t ath79_wdt_write(struct file *file, const char *data, 144 size_t len, loff_t *ppos) 145 { 146 if (len) { 147 if (!nowayout) { 148 size_t i; 149 150 clear_bit(WDT_FLAGS_EXPECT_CLOSE, &wdt_flags); 151 152 for (i = 0; i != len; i++) { 153 char c; 154 155 if (get_user(c, data + i)) 156 return -EFAULT; 157 158 if (c == 'V') 159 set_bit(WDT_FLAGS_EXPECT_CLOSE, 160 &wdt_flags); 161 } 162 } 163 164 ath79_wdt_keepalive(); 165 } 166 167 return len; 168 } 169 170 static const struct watchdog_info ath79_wdt_info = { 171 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | 172 WDIOF_MAGICCLOSE | WDIOF_CARDRESET, 173 .firmware_version = 0, 174 .identity = "ATH79 watchdog", 175 }; 176 177 static long ath79_wdt_ioctl(struct file *file, unsigned int cmd, 178 unsigned long arg) 179 { 180 void __user *argp = (void __user *)arg; 181 int __user *p = argp; 182 int err; 183 int t; 184 185 switch (cmd) { 186 case WDIOC_GETSUPPORT: 187 err = copy_to_user(argp, &ath79_wdt_info, 188 sizeof(ath79_wdt_info)) ? -EFAULT : 0; 189 break; 190 191 case WDIOC_GETSTATUS: 192 err = put_user(0, p); 193 break; 194 195 case WDIOC_GETBOOTSTATUS: 196 err = put_user(boot_status, p); 197 break; 198 199 case WDIOC_KEEPALIVE: 200 ath79_wdt_keepalive(); 201 err = 0; 202 break; 203 204 case WDIOC_SETTIMEOUT: 205 err = get_user(t, p); 206 if (err) 207 break; 208 209 err = ath79_wdt_set_timeout(t); 210 if (err) 211 break; 212 213 /* fallthrough */ 214 case WDIOC_GETTIMEOUT: 215 err = put_user(timeout, p); 216 break; 217 218 default: 219 err = -ENOTTY; 220 break; 221 } 222 223 return err; 224 } 225 226 static const struct file_operations ath79_wdt_fops = { 227 .owner = THIS_MODULE, 228 .llseek = no_llseek, 229 .write = ath79_wdt_write, 230 .unlocked_ioctl = ath79_wdt_ioctl, 231 .open = ath79_wdt_open, 232 .release = ath79_wdt_release, 233 }; 234 235 static struct miscdevice ath79_wdt_miscdev = { 236 .minor = WATCHDOG_MINOR, 237 .name = "watchdog", 238 .fops = &ath79_wdt_fops, 239 }; 240 241 static int ath79_wdt_probe(struct platform_device *pdev) 242 { 243 struct resource *res; 244 u32 ctrl; 245 int err; 246 247 if (wdt_base) 248 return -EBUSY; 249 250 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 251 wdt_base = devm_ioremap_resource(&pdev->dev, res); 252 if (IS_ERR(wdt_base)) 253 return PTR_ERR(wdt_base); 254 255 wdt_clk = devm_clk_get(&pdev->dev, "wdt"); 256 if (IS_ERR(wdt_clk)) 257 return PTR_ERR(wdt_clk); 258 259 err = clk_enable(wdt_clk); 260 if (err) 261 return err; 262 263 wdt_freq = clk_get_rate(wdt_clk); 264 if (!wdt_freq) { 265 err = -EINVAL; 266 goto err_clk_disable; 267 } 268 269 max_timeout = (0xfffffffful / wdt_freq); 270 if (timeout < 1 || timeout > max_timeout) { 271 timeout = max_timeout; 272 dev_info(&pdev->dev, 273 "timeout value must be 0 < timeout < %d, using %d\n", 274 max_timeout, timeout); 275 } 276 277 ctrl = ath79_wdt_rr(WDOG_REG_CTRL); 278 boot_status = (ctrl & WDOG_CTRL_LAST_RESET) ? WDIOF_CARDRESET : 0; 279 280 err = misc_register(&ath79_wdt_miscdev); 281 if (err) { 282 dev_err(&pdev->dev, 283 "unable to register misc device, err=%d\n", err); 284 goto err_clk_disable; 285 } 286 287 return 0; 288 289 err_clk_disable: 290 clk_disable(wdt_clk); 291 return err; 292 } 293 294 static int ath79_wdt_remove(struct platform_device *pdev) 295 { 296 misc_deregister(&ath79_wdt_miscdev); 297 clk_disable(wdt_clk); 298 return 0; 299 } 300 301 static void ath97_wdt_shutdown(struct platform_device *pdev) 302 { 303 ath79_wdt_disable(); 304 } 305 306 #ifdef CONFIG_OF 307 static const struct of_device_id ath79_wdt_match[] = { 308 { .compatible = "qca,ar7130-wdt" }, 309 {}, 310 }; 311 MODULE_DEVICE_TABLE(of, ath79_wdt_match); 312 #endif 313 314 static struct platform_driver ath79_wdt_driver = { 315 .probe = ath79_wdt_probe, 316 .remove = ath79_wdt_remove, 317 .shutdown = ath97_wdt_shutdown, 318 .driver = { 319 .name = DRIVER_NAME, 320 .owner = THIS_MODULE, 321 .of_match_table = of_match_ptr(ath79_wdt_match), 322 }, 323 }; 324 325 module_platform_driver(ath79_wdt_driver); 326 327 MODULE_DESCRIPTION("Atheros AR71XX/AR724X/AR913X hardware watchdog driver"); 328 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org"); 329 MODULE_AUTHOR("Imre Kaloz <kaloz@openwrt.org"); 330 MODULE_LICENSE("GPL v2"); 331 MODULE_ALIAS("platform:" DRIVER_NAME); 332 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); 333