1 /* 2 * sunxi Watchdog Driver 3 * 4 * Copyright (c) 2013 Carlo Caione 5 * 2012 Henrik Nordstrom 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * Based on xen_wdt.c 13 * (c) Copyright 2010 Novell, Inc. 14 */ 15 16 #include <linux/clk.h> 17 #include <linux/delay.h> 18 #include <linux/err.h> 19 #include <linux/init.h> 20 #include <linux/io.h> 21 #include <linux/kernel.h> 22 #include <linux/module.h> 23 #include <linux/moduleparam.h> 24 #include <linux/notifier.h> 25 #include <linux/of.h> 26 #include <linux/of_device.h> 27 #include <linux/platform_device.h> 28 #include <linux/reboot.h> 29 #include <linux/types.h> 30 #include <linux/watchdog.h> 31 32 #define WDT_MAX_TIMEOUT 16 33 #define WDT_MIN_TIMEOUT 1 34 #define WDT_TIMEOUT_MASK 0x0F 35 36 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1)) 37 38 #define WDT_MODE_EN (1 << 0) 39 40 #define DRV_NAME "sunxi-wdt" 41 #define DRV_VERSION "1.0" 42 43 static bool nowayout = WATCHDOG_NOWAYOUT; 44 static unsigned int timeout = WDT_MAX_TIMEOUT; 45 46 /* 47 * This structure stores the register offsets for different variants 48 * of Allwinner's watchdog hardware. 49 */ 50 struct sunxi_wdt_reg { 51 u8 wdt_ctrl; 52 u8 wdt_cfg; 53 u8 wdt_mode; 54 u8 wdt_timeout_shift; 55 u8 wdt_reset_mask; 56 u8 wdt_reset_val; 57 }; 58 59 struct sunxi_wdt_dev { 60 struct watchdog_device wdt_dev; 61 void __iomem *wdt_base; 62 const struct sunxi_wdt_reg *wdt_regs; 63 struct notifier_block restart_handler; 64 }; 65 66 /* 67 * wdt_timeout_map maps the watchdog timer interval value in seconds to 68 * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3 69 * 70 * [timeout seconds] = register value 71 * 72 */ 73 74 static const int wdt_timeout_map[] = { 75 [1] = 0x1, /* 1s */ 76 [2] = 0x2, /* 2s */ 77 [3] = 0x3, /* 3s */ 78 [4] = 0x4, /* 4s */ 79 [5] = 0x5, /* 5s */ 80 [6] = 0x6, /* 6s */ 81 [8] = 0x7, /* 8s */ 82 [10] = 0x8, /* 10s */ 83 [12] = 0x9, /* 12s */ 84 [14] = 0xA, /* 14s */ 85 [16] = 0xB, /* 16s */ 86 }; 87 88 89 static int sunxi_restart_handle(struct notifier_block *this, unsigned long mode, 90 void *cmd) 91 { 92 struct sunxi_wdt_dev *sunxi_wdt = container_of(this, 93 struct sunxi_wdt_dev, 94 restart_handler); 95 void __iomem *wdt_base = sunxi_wdt->wdt_base; 96 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 97 u32 val; 98 99 /* Set system reset function */ 100 val = readl(wdt_base + regs->wdt_cfg); 101 val &= ~(regs->wdt_reset_mask); 102 val |= regs->wdt_reset_val; 103 writel(val, wdt_base + regs->wdt_cfg); 104 105 /* Set lowest timeout and enable watchdog */ 106 val = readl(wdt_base + regs->wdt_mode); 107 val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); 108 val |= WDT_MODE_EN; 109 writel(val, wdt_base + regs->wdt_mode); 110 111 /* 112 * Restart the watchdog. The default (and lowest) interval 113 * value for the watchdog is 0.5s. 114 */ 115 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); 116 117 while (1) { 118 mdelay(5); 119 val = readl(wdt_base + regs->wdt_mode); 120 val |= WDT_MODE_EN; 121 writel(val, wdt_base + regs->wdt_mode); 122 } 123 return NOTIFY_DONE; 124 } 125 126 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev) 127 { 128 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 129 void __iomem *wdt_base = sunxi_wdt->wdt_base; 130 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 131 132 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); 133 134 return 0; 135 } 136 137 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev, 138 unsigned int timeout) 139 { 140 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 141 void __iomem *wdt_base = sunxi_wdt->wdt_base; 142 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 143 u32 reg; 144 145 if (wdt_timeout_map[timeout] == 0) 146 timeout++; 147 148 sunxi_wdt->wdt_dev.timeout = timeout; 149 150 reg = readl(wdt_base + regs->wdt_mode); 151 reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); 152 reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift; 153 writel(reg, wdt_base + regs->wdt_mode); 154 155 sunxi_wdt_ping(wdt_dev); 156 157 return 0; 158 } 159 160 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev) 161 { 162 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 163 void __iomem *wdt_base = sunxi_wdt->wdt_base; 164 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 165 166 writel(0, wdt_base + regs->wdt_mode); 167 168 return 0; 169 } 170 171 static int sunxi_wdt_start(struct watchdog_device *wdt_dev) 172 { 173 u32 reg; 174 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 175 void __iomem *wdt_base = sunxi_wdt->wdt_base; 176 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 177 int ret; 178 179 ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev, 180 sunxi_wdt->wdt_dev.timeout); 181 if (ret < 0) 182 return ret; 183 184 /* Set system reset function */ 185 reg = readl(wdt_base + regs->wdt_cfg); 186 reg &= ~(regs->wdt_reset_mask); 187 reg |= ~(regs->wdt_reset_val); 188 writel(reg, wdt_base + regs->wdt_cfg); 189 190 /* Enable watchdog */ 191 reg = readl(wdt_base + regs->wdt_mode); 192 reg |= WDT_MODE_EN; 193 writel(reg, wdt_base + regs->wdt_mode); 194 195 return 0; 196 } 197 198 static const struct watchdog_info sunxi_wdt_info = { 199 .identity = DRV_NAME, 200 .options = WDIOF_SETTIMEOUT | 201 WDIOF_KEEPALIVEPING | 202 WDIOF_MAGICCLOSE, 203 }; 204 205 static const struct watchdog_ops sunxi_wdt_ops = { 206 .owner = THIS_MODULE, 207 .start = sunxi_wdt_start, 208 .stop = sunxi_wdt_stop, 209 .ping = sunxi_wdt_ping, 210 .set_timeout = sunxi_wdt_set_timeout, 211 }; 212 213 static const struct sunxi_wdt_reg sun4i_wdt_reg = { 214 .wdt_ctrl = 0x00, 215 .wdt_cfg = 0x04, 216 .wdt_mode = 0x04, 217 .wdt_timeout_shift = 3, 218 .wdt_reset_mask = 0x02, 219 .wdt_reset_val = 0x02, 220 }; 221 222 static const struct sunxi_wdt_reg sun6i_wdt_reg = { 223 .wdt_ctrl = 0x10, 224 .wdt_cfg = 0x14, 225 .wdt_mode = 0x18, 226 .wdt_timeout_shift = 4, 227 .wdt_reset_mask = 0x03, 228 .wdt_reset_val = 0x01, 229 }; 230 231 static const struct of_device_id sunxi_wdt_dt_ids[] = { 232 { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg }, 233 { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg }, 234 { /* sentinel */ } 235 }; 236 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids); 237 238 static int sunxi_wdt_probe(struct platform_device *pdev) 239 { 240 struct sunxi_wdt_dev *sunxi_wdt; 241 const struct of_device_id *device; 242 struct resource *res; 243 int err; 244 245 sunxi_wdt = devm_kzalloc(&pdev->dev, sizeof(*sunxi_wdt), GFP_KERNEL); 246 if (!sunxi_wdt) 247 return -EINVAL; 248 249 platform_set_drvdata(pdev, sunxi_wdt); 250 251 device = of_match_device(sunxi_wdt_dt_ids, &pdev->dev); 252 if (!device) 253 return -ENODEV; 254 255 sunxi_wdt->wdt_regs = device->data; 256 257 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 258 sunxi_wdt->wdt_base = devm_ioremap_resource(&pdev->dev, res); 259 if (IS_ERR(sunxi_wdt->wdt_base)) 260 return PTR_ERR(sunxi_wdt->wdt_base); 261 262 sunxi_wdt->wdt_dev.info = &sunxi_wdt_info; 263 sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops; 264 sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 265 sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 266 sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 267 sunxi_wdt->wdt_dev.parent = &pdev->dev; 268 269 watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, &pdev->dev); 270 watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout); 271 272 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt); 273 274 sunxi_wdt_stop(&sunxi_wdt->wdt_dev); 275 276 err = watchdog_register_device(&sunxi_wdt->wdt_dev); 277 if (unlikely(err)) 278 return err; 279 280 sunxi_wdt->restart_handler.notifier_call = sunxi_restart_handle; 281 sunxi_wdt->restart_handler.priority = 128; 282 err = register_restart_handler(&sunxi_wdt->restart_handler); 283 if (err) 284 dev_err(&pdev->dev, 285 "cannot register restart handler (err=%d)\n", err); 286 287 dev_info(&pdev->dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", 288 sunxi_wdt->wdt_dev.timeout, nowayout); 289 290 return 0; 291 } 292 293 static int sunxi_wdt_remove(struct platform_device *pdev) 294 { 295 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev); 296 297 unregister_restart_handler(&sunxi_wdt->restart_handler); 298 299 watchdog_unregister_device(&sunxi_wdt->wdt_dev); 300 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, NULL); 301 302 return 0; 303 } 304 305 static void sunxi_wdt_shutdown(struct platform_device *pdev) 306 { 307 struct sunxi_wdt_dev *sunxi_wdt = platform_get_drvdata(pdev); 308 309 sunxi_wdt_stop(&sunxi_wdt->wdt_dev); 310 } 311 312 static struct platform_driver sunxi_wdt_driver = { 313 .probe = sunxi_wdt_probe, 314 .remove = sunxi_wdt_remove, 315 .shutdown = sunxi_wdt_shutdown, 316 .driver = { 317 .name = DRV_NAME, 318 .of_match_table = sunxi_wdt_dt_ids, 319 }, 320 }; 321 322 module_platform_driver(sunxi_wdt_driver); 323 324 module_param(timeout, uint, 0); 325 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 326 327 module_param(nowayout, bool, 0); 328 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 329 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 330 331 MODULE_LICENSE("GPL"); 332 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>"); 333 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>"); 334 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver"); 335 MODULE_VERSION(DRV_VERSION); 336