1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * sunxi Watchdog Driver 4 * 5 * Copyright (c) 2013 Carlo Caione 6 * 2012 Henrik Nordstrom 7 * 8 * Based on xen_wdt.c 9 * (c) Copyright 2010 Novell, Inc. 10 */ 11 12 #include <linux/clk.h> 13 #include <linux/delay.h> 14 #include <linux/err.h> 15 #include <linux/init.h> 16 #include <linux/io.h> 17 #include <linux/kernel.h> 18 #include <linux/module.h> 19 #include <linux/moduleparam.h> 20 #include <linux/of.h> 21 #include <linux/of_device.h> 22 #include <linux/platform_device.h> 23 #include <linux/types.h> 24 #include <linux/watchdog.h> 25 26 #define WDT_MAX_TIMEOUT 16 27 #define WDT_MIN_TIMEOUT 1 28 #define WDT_TIMEOUT_MASK 0x0F 29 30 #define WDT_CTRL_RELOAD ((1 << 0) | (0x0a57 << 1)) 31 32 #define WDT_MODE_EN (1 << 0) 33 34 #define DRV_NAME "sunxi-wdt" 35 #define DRV_VERSION "1.0" 36 37 static bool nowayout = WATCHDOG_NOWAYOUT; 38 static unsigned int timeout; 39 40 /* 41 * This structure stores the register offsets for different variants 42 * of Allwinner's watchdog hardware. 43 */ 44 struct sunxi_wdt_reg { 45 u8 wdt_ctrl; 46 u8 wdt_cfg; 47 u8 wdt_mode; 48 u8 wdt_timeout_shift; 49 u8 wdt_reset_mask; 50 u8 wdt_reset_val; 51 }; 52 53 struct sunxi_wdt_dev { 54 struct watchdog_device wdt_dev; 55 void __iomem *wdt_base; 56 const struct sunxi_wdt_reg *wdt_regs; 57 }; 58 59 /* 60 * wdt_timeout_map maps the watchdog timer interval value in seconds to 61 * the value of the register WDT_MODE at bits .wdt_timeout_shift ~ +3 62 * 63 * [timeout seconds] = register value 64 * 65 */ 66 67 static const int wdt_timeout_map[] = { 68 [1] = 0x1, /* 1s */ 69 [2] = 0x2, /* 2s */ 70 [3] = 0x3, /* 3s */ 71 [4] = 0x4, /* 4s */ 72 [5] = 0x5, /* 5s */ 73 [6] = 0x6, /* 6s */ 74 [8] = 0x7, /* 8s */ 75 [10] = 0x8, /* 10s */ 76 [12] = 0x9, /* 12s */ 77 [14] = 0xA, /* 14s */ 78 [16] = 0xB, /* 16s */ 79 }; 80 81 82 static int sunxi_wdt_restart(struct watchdog_device *wdt_dev, 83 unsigned long action, void *data) 84 { 85 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 86 void __iomem *wdt_base = sunxi_wdt->wdt_base; 87 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 88 u32 val; 89 90 /* Set system reset function */ 91 val = readl(wdt_base + regs->wdt_cfg); 92 val &= ~(regs->wdt_reset_mask); 93 val |= regs->wdt_reset_val; 94 writel(val, wdt_base + regs->wdt_cfg); 95 96 /* Set lowest timeout and enable watchdog */ 97 val = readl(wdt_base + regs->wdt_mode); 98 val &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); 99 val |= WDT_MODE_EN; 100 writel(val, wdt_base + regs->wdt_mode); 101 102 /* 103 * Restart the watchdog. The default (and lowest) interval 104 * value for the watchdog is 0.5s. 105 */ 106 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); 107 108 while (1) { 109 mdelay(5); 110 val = readl(wdt_base + regs->wdt_mode); 111 val |= WDT_MODE_EN; 112 writel(val, wdt_base + regs->wdt_mode); 113 } 114 return 0; 115 } 116 117 static int sunxi_wdt_ping(struct watchdog_device *wdt_dev) 118 { 119 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 120 void __iomem *wdt_base = sunxi_wdt->wdt_base; 121 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 122 123 writel(WDT_CTRL_RELOAD, wdt_base + regs->wdt_ctrl); 124 125 return 0; 126 } 127 128 static int sunxi_wdt_set_timeout(struct watchdog_device *wdt_dev, 129 unsigned int timeout) 130 { 131 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 132 void __iomem *wdt_base = sunxi_wdt->wdt_base; 133 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 134 u32 reg; 135 136 if (wdt_timeout_map[timeout] == 0) 137 timeout++; 138 139 sunxi_wdt->wdt_dev.timeout = timeout; 140 141 reg = readl(wdt_base + regs->wdt_mode); 142 reg &= ~(WDT_TIMEOUT_MASK << regs->wdt_timeout_shift); 143 reg |= wdt_timeout_map[timeout] << regs->wdt_timeout_shift; 144 writel(reg, wdt_base + regs->wdt_mode); 145 146 sunxi_wdt_ping(wdt_dev); 147 148 return 0; 149 } 150 151 static int sunxi_wdt_stop(struct watchdog_device *wdt_dev) 152 { 153 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 154 void __iomem *wdt_base = sunxi_wdt->wdt_base; 155 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 156 157 writel(0, wdt_base + regs->wdt_mode); 158 159 return 0; 160 } 161 162 static int sunxi_wdt_start(struct watchdog_device *wdt_dev) 163 { 164 u32 reg; 165 struct sunxi_wdt_dev *sunxi_wdt = watchdog_get_drvdata(wdt_dev); 166 void __iomem *wdt_base = sunxi_wdt->wdt_base; 167 const struct sunxi_wdt_reg *regs = sunxi_wdt->wdt_regs; 168 int ret; 169 170 ret = sunxi_wdt_set_timeout(&sunxi_wdt->wdt_dev, 171 sunxi_wdt->wdt_dev.timeout); 172 if (ret < 0) 173 return ret; 174 175 /* Set system reset function */ 176 reg = readl(wdt_base + regs->wdt_cfg); 177 reg &= ~(regs->wdt_reset_mask); 178 reg |= regs->wdt_reset_val; 179 writel(reg, wdt_base + regs->wdt_cfg); 180 181 /* Enable watchdog */ 182 reg = readl(wdt_base + regs->wdt_mode); 183 reg |= WDT_MODE_EN; 184 writel(reg, wdt_base + regs->wdt_mode); 185 186 return 0; 187 } 188 189 static const struct watchdog_info sunxi_wdt_info = { 190 .identity = DRV_NAME, 191 .options = WDIOF_SETTIMEOUT | 192 WDIOF_KEEPALIVEPING | 193 WDIOF_MAGICCLOSE, 194 }; 195 196 static const struct watchdog_ops sunxi_wdt_ops = { 197 .owner = THIS_MODULE, 198 .start = sunxi_wdt_start, 199 .stop = sunxi_wdt_stop, 200 .ping = sunxi_wdt_ping, 201 .set_timeout = sunxi_wdt_set_timeout, 202 .restart = sunxi_wdt_restart, 203 }; 204 205 static const struct sunxi_wdt_reg sun4i_wdt_reg = { 206 .wdt_ctrl = 0x00, 207 .wdt_cfg = 0x04, 208 .wdt_mode = 0x04, 209 .wdt_timeout_shift = 3, 210 .wdt_reset_mask = 0x02, 211 .wdt_reset_val = 0x02, 212 }; 213 214 static const struct sunxi_wdt_reg sun6i_wdt_reg = { 215 .wdt_ctrl = 0x10, 216 .wdt_cfg = 0x14, 217 .wdt_mode = 0x18, 218 .wdt_timeout_shift = 4, 219 .wdt_reset_mask = 0x03, 220 .wdt_reset_val = 0x01, 221 }; 222 223 static const struct of_device_id sunxi_wdt_dt_ids[] = { 224 { .compatible = "allwinner,sun4i-a10-wdt", .data = &sun4i_wdt_reg }, 225 { .compatible = "allwinner,sun6i-a31-wdt", .data = &sun6i_wdt_reg }, 226 { /* sentinel */ } 227 }; 228 MODULE_DEVICE_TABLE(of, sunxi_wdt_dt_ids); 229 230 static int sunxi_wdt_probe(struct platform_device *pdev) 231 { 232 struct device *dev = &pdev->dev; 233 struct sunxi_wdt_dev *sunxi_wdt; 234 int err; 235 236 sunxi_wdt = devm_kzalloc(dev, sizeof(*sunxi_wdt), GFP_KERNEL); 237 if (!sunxi_wdt) 238 return -ENOMEM; 239 240 sunxi_wdt->wdt_regs = of_device_get_match_data(dev); 241 if (!sunxi_wdt->wdt_regs) 242 return -ENODEV; 243 244 sunxi_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0); 245 if (IS_ERR(sunxi_wdt->wdt_base)) 246 return PTR_ERR(sunxi_wdt->wdt_base); 247 248 sunxi_wdt->wdt_dev.info = &sunxi_wdt_info; 249 sunxi_wdt->wdt_dev.ops = &sunxi_wdt_ops; 250 sunxi_wdt->wdt_dev.timeout = WDT_MAX_TIMEOUT; 251 sunxi_wdt->wdt_dev.max_timeout = WDT_MAX_TIMEOUT; 252 sunxi_wdt->wdt_dev.min_timeout = WDT_MIN_TIMEOUT; 253 sunxi_wdt->wdt_dev.parent = dev; 254 255 watchdog_init_timeout(&sunxi_wdt->wdt_dev, timeout, dev); 256 watchdog_set_nowayout(&sunxi_wdt->wdt_dev, nowayout); 257 watchdog_set_restart_priority(&sunxi_wdt->wdt_dev, 128); 258 259 watchdog_set_drvdata(&sunxi_wdt->wdt_dev, sunxi_wdt); 260 261 sunxi_wdt_stop(&sunxi_wdt->wdt_dev); 262 263 watchdog_stop_on_reboot(&sunxi_wdt->wdt_dev); 264 err = devm_watchdog_register_device(dev, &sunxi_wdt->wdt_dev); 265 if (unlikely(err)) 266 return err; 267 268 dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)", 269 sunxi_wdt->wdt_dev.timeout, nowayout); 270 271 return 0; 272 } 273 274 static struct platform_driver sunxi_wdt_driver = { 275 .probe = sunxi_wdt_probe, 276 .driver = { 277 .name = DRV_NAME, 278 .of_match_table = sunxi_wdt_dt_ids, 279 }, 280 }; 281 282 module_platform_driver(sunxi_wdt_driver); 283 284 module_param(timeout, uint, 0); 285 MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds"); 286 287 module_param(nowayout, bool, 0); 288 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " 289 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 290 291 MODULE_LICENSE("GPL"); 292 MODULE_AUTHOR("Carlo Caione <carlo.caione@gmail.com>"); 293 MODULE_AUTHOR("Henrik Nordstrom <henrik@henriknordstrom.net>"); 294 MODULE_DESCRIPTION("sunxi WatchDog Timer Driver"); 295 MODULE_VERSION(DRV_VERSION); 296