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