1 /* 2 * Intel Atom E6xx Watchdog driver 3 * 4 * Copyright (C) 2011 Alexander Stein 5 * <alexander.stein@systec-electronic.com> 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of version 2 of the GNU General 9 * Public License as published by the Free Software Foundation. 10 * 11 * This program is distributed in the hope that it will be 12 * useful, but WITHOUT ANY WARRANTY; without even the implied 13 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR 14 * PURPOSE. See the GNU General Public License for more details. 15 * You should have received a copy of the GNU General Public 16 * License along with this program; if not, write to the Free 17 * Software Foundation, Inc., 59 Temple Place - Suite 330, 18 * Boston, MA 02111-1307, USA. 19 * The full GNU General Public License is included in this 20 * distribution in the file called COPYING. 21 * 22 */ 23 24 #include <linux/module.h> 25 #include <linux/moduleparam.h> 26 #include <linux/platform_device.h> 27 #include <linux/io.h> 28 #include <linux/kernel.h> 29 #include <linux/types.h> 30 #include <linux/watchdog.h> 31 #include <linux/seq_file.h> 32 #include <linux/debugfs.h> 33 #include <linux/uaccess.h> 34 #include <linux/spinlock.h> 35 36 #define DRIVER_NAME "ie6xx_wdt" 37 38 #define PV1 0x00 39 #define PV2 0x04 40 41 #define RR0 0x0c 42 #define RR1 0x0d 43 #define WDT_RELOAD 0x01 44 #define WDT_TOUT 0x02 45 46 #define WDTCR 0x10 47 #define WDT_PRE_SEL 0x04 48 #define WDT_RESET_SEL 0x08 49 #define WDT_RESET_EN 0x10 50 #define WDT_TOUT_EN 0x20 51 52 #define DCR 0x14 53 54 #define WDTLR 0x18 55 #define WDT_LOCK 0x01 56 #define WDT_ENABLE 0x02 57 #define WDT_TOUT_CNF 0x03 58 59 #define MIN_TIME 1 60 #define MAX_TIME (10 * 60) /* 10 minutes */ 61 #define DEFAULT_TIME 60 62 63 static unsigned int timeout = DEFAULT_TIME; 64 module_param(timeout, uint, 0); 65 MODULE_PARM_DESC(timeout, 66 "Default Watchdog timer setting (" 67 __MODULE_STRING(DEFAULT_TIME) "s)." 68 "The range is from 1 to 600"); 69 70 static bool nowayout = WATCHDOG_NOWAYOUT; 71 module_param(nowayout, bool, 0); 72 MODULE_PARM_DESC(nowayout, 73 "Watchdog cannot be stopped once started (default=" 74 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 75 76 static u8 resetmode = 0x10; 77 module_param(resetmode, byte, 0); 78 MODULE_PARM_DESC(resetmode, 79 "Resetmode bits: 0x08 warm reset (cold reset otherwise), " 80 "0x10 reset enable, 0x20 disable toggle GPIO[4] (default=0x10)"); 81 82 static struct { 83 unsigned short sch_wdtba; 84 struct spinlock unlock_sequence; 85 #ifdef CONFIG_DEBUG_FS 86 struct dentry *debugfs; 87 #endif 88 } ie6xx_wdt_data; 89 90 /* 91 * This is needed to write to preload and reload registers 92 * struct ie6xx_wdt_data.unlock_sequence must be used 93 * to prevent sequence interrupts 94 */ 95 static void ie6xx_wdt_unlock_registers(void) 96 { 97 outb(0x80, ie6xx_wdt_data.sch_wdtba + RR0); 98 outb(0x86, ie6xx_wdt_data.sch_wdtba + RR0); 99 } 100 101 static int ie6xx_wdt_ping(struct watchdog_device *wdd) 102 { 103 spin_lock(&ie6xx_wdt_data.unlock_sequence); 104 ie6xx_wdt_unlock_registers(); 105 outb(WDT_RELOAD, ie6xx_wdt_data.sch_wdtba + RR1); 106 spin_unlock(&ie6xx_wdt_data.unlock_sequence); 107 return 0; 108 } 109 110 static int ie6xx_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t) 111 { 112 u32 preload; 113 u64 clock; 114 u8 wdtcr; 115 116 /* Watchdog clock is PCI Clock (33MHz) */ 117 clock = 33000000; 118 /* and the preload value is loaded into [34:15] of the down counter */ 119 preload = (t * clock) >> 15; 120 /* 121 * Manual states preload must be one less. 122 * Does not wrap as t is at least 1 123 */ 124 preload -= 1; 125 126 spin_lock(&ie6xx_wdt_data.unlock_sequence); 127 128 /* Set ResetMode & Enable prescaler for range 10ms to 10 min */ 129 wdtcr = resetmode & 0x38; 130 outb(wdtcr, ie6xx_wdt_data.sch_wdtba + WDTCR); 131 132 ie6xx_wdt_unlock_registers(); 133 outl(0, ie6xx_wdt_data.sch_wdtba + PV1); 134 135 ie6xx_wdt_unlock_registers(); 136 outl(preload, ie6xx_wdt_data.sch_wdtba + PV2); 137 138 ie6xx_wdt_unlock_registers(); 139 outb(WDT_RELOAD | WDT_TOUT, ie6xx_wdt_data.sch_wdtba + RR1); 140 141 spin_unlock(&ie6xx_wdt_data.unlock_sequence); 142 143 wdd->timeout = t; 144 return 0; 145 } 146 147 static int ie6xx_wdt_start(struct watchdog_device *wdd) 148 { 149 ie6xx_wdt_set_timeout(wdd, wdd->timeout); 150 151 /* Enable the watchdog timer */ 152 spin_lock(&ie6xx_wdt_data.unlock_sequence); 153 outb(WDT_ENABLE, ie6xx_wdt_data.sch_wdtba + WDTLR); 154 spin_unlock(&ie6xx_wdt_data.unlock_sequence); 155 156 return 0; 157 } 158 159 static int ie6xx_wdt_stop(struct watchdog_device *wdd) 160 { 161 if (inb(ie6xx_wdt_data.sch_wdtba + WDTLR) & WDT_LOCK) 162 return -1; 163 164 /* Disable the watchdog timer */ 165 spin_lock(&ie6xx_wdt_data.unlock_sequence); 166 outb(0, ie6xx_wdt_data.sch_wdtba + WDTLR); 167 spin_unlock(&ie6xx_wdt_data.unlock_sequence); 168 169 return 0; 170 } 171 172 static const struct watchdog_info ie6xx_wdt_info = { 173 .identity = "Intel Atom E6xx Watchdog", 174 .options = WDIOF_SETTIMEOUT | 175 WDIOF_MAGICCLOSE | 176 WDIOF_KEEPALIVEPING, 177 }; 178 179 static const struct watchdog_ops ie6xx_wdt_ops = { 180 .owner = THIS_MODULE, 181 .start = ie6xx_wdt_start, 182 .stop = ie6xx_wdt_stop, 183 .ping = ie6xx_wdt_ping, 184 .set_timeout = ie6xx_wdt_set_timeout, 185 }; 186 187 static struct watchdog_device ie6xx_wdt_dev = { 188 .info = &ie6xx_wdt_info, 189 .ops = &ie6xx_wdt_ops, 190 .min_timeout = MIN_TIME, 191 .max_timeout = MAX_TIME, 192 }; 193 194 #ifdef CONFIG_DEBUG_FS 195 196 static int ie6xx_wdt_show(struct seq_file *s, void *unused) 197 { 198 seq_printf(s, "PV1 = 0x%08x\n", 199 inl(ie6xx_wdt_data.sch_wdtba + PV1)); 200 seq_printf(s, "PV2 = 0x%08x\n", 201 inl(ie6xx_wdt_data.sch_wdtba + PV2)); 202 seq_printf(s, "RR = 0x%08x\n", 203 inw(ie6xx_wdt_data.sch_wdtba + RR0)); 204 seq_printf(s, "WDTCR = 0x%08x\n", 205 inw(ie6xx_wdt_data.sch_wdtba + WDTCR)); 206 seq_printf(s, "DCR = 0x%08x\n", 207 inl(ie6xx_wdt_data.sch_wdtba + DCR)); 208 seq_printf(s, "WDTLR = 0x%08x\n", 209 inw(ie6xx_wdt_data.sch_wdtba + WDTLR)); 210 211 seq_printf(s, "\n"); 212 return 0; 213 } 214 215 DEFINE_SHOW_ATTRIBUTE(ie6xx_wdt); 216 217 static void ie6xx_wdt_debugfs_init(void) 218 { 219 /* /sys/kernel/debug/ie6xx_wdt */ 220 ie6xx_wdt_data.debugfs = debugfs_create_file("ie6xx_wdt", 221 S_IFREG | S_IRUGO, NULL, NULL, &ie6xx_wdt_fops); 222 } 223 224 static void ie6xx_wdt_debugfs_exit(void) 225 { 226 debugfs_remove(ie6xx_wdt_data.debugfs); 227 } 228 229 #else 230 static void ie6xx_wdt_debugfs_init(void) 231 { 232 } 233 234 static void ie6xx_wdt_debugfs_exit(void) 235 { 236 } 237 #endif 238 239 static int ie6xx_wdt_probe(struct platform_device *pdev) 240 { 241 struct resource *res; 242 u8 wdtlr; 243 int ret; 244 245 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 246 if (!res) 247 return -ENODEV; 248 249 if (!request_region(res->start, resource_size(res), pdev->name)) { 250 dev_err(&pdev->dev, "Watchdog region 0x%llx already in use!\n", 251 (u64)res->start); 252 return -EBUSY; 253 } 254 255 ie6xx_wdt_data.sch_wdtba = res->start; 256 dev_dbg(&pdev->dev, "WDT = 0x%X\n", ie6xx_wdt_data.sch_wdtba); 257 258 ie6xx_wdt_dev.timeout = timeout; 259 watchdog_set_nowayout(&ie6xx_wdt_dev, nowayout); 260 ie6xx_wdt_dev.parent = &pdev->dev; 261 262 spin_lock_init(&ie6xx_wdt_data.unlock_sequence); 263 264 wdtlr = inb(ie6xx_wdt_data.sch_wdtba + WDTLR); 265 if (wdtlr & WDT_LOCK) 266 dev_warn(&pdev->dev, 267 "Watchdog Timer is Locked (Reg=0x%x)\n", wdtlr); 268 269 ie6xx_wdt_debugfs_init(); 270 271 ret = watchdog_register_device(&ie6xx_wdt_dev); 272 if (ret) { 273 dev_err(&pdev->dev, 274 "Watchdog timer: cannot register device (err =%d)\n", 275 ret); 276 goto misc_register_error; 277 } 278 279 return 0; 280 281 misc_register_error: 282 ie6xx_wdt_debugfs_exit(); 283 release_region(res->start, resource_size(res)); 284 ie6xx_wdt_data.sch_wdtba = 0; 285 return ret; 286 } 287 288 static int ie6xx_wdt_remove(struct platform_device *pdev) 289 { 290 struct resource *res; 291 292 res = platform_get_resource(pdev, IORESOURCE_IO, 0); 293 ie6xx_wdt_stop(NULL); 294 watchdog_unregister_device(&ie6xx_wdt_dev); 295 ie6xx_wdt_debugfs_exit(); 296 release_region(res->start, resource_size(res)); 297 ie6xx_wdt_data.sch_wdtba = 0; 298 299 return 0; 300 } 301 302 static struct platform_driver ie6xx_wdt_driver = { 303 .probe = ie6xx_wdt_probe, 304 .remove = ie6xx_wdt_remove, 305 .driver = { 306 .name = DRIVER_NAME, 307 }, 308 }; 309 310 static int __init ie6xx_wdt_init(void) 311 { 312 /* Check boot parameters to verify that their initial values */ 313 /* are in range. */ 314 if ((timeout < MIN_TIME) || 315 (timeout > MAX_TIME)) { 316 pr_err("Watchdog timer: value of timeout %d (dec) " 317 "is out of range from %d to %d (dec)\n", 318 timeout, MIN_TIME, MAX_TIME); 319 return -EINVAL; 320 } 321 322 return platform_driver_register(&ie6xx_wdt_driver); 323 } 324 325 static void __exit ie6xx_wdt_exit(void) 326 { 327 platform_driver_unregister(&ie6xx_wdt_driver); 328 } 329 330 late_initcall(ie6xx_wdt_init); 331 module_exit(ie6xx_wdt_exit); 332 333 MODULE_AUTHOR("Alexander Stein <alexander.stein@systec-electronic.com>"); 334 MODULE_DESCRIPTION("Intel Atom E6xx Watchdog Device Driver"); 335 MODULE_LICENSE("GPL"); 336 MODULE_ALIAS("platform:" DRIVER_NAME); 337