1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Watchdog driver for the UniPhier watchdog timer 4 * 5 * (c) Copyright 2014 Panasonic Corporation 6 * (c) Copyright 2016 Socionext Inc. 7 * All rights reserved. 8 */ 9 10 #include <linux/bitops.h> 11 #include <linux/mfd/syscon.h> 12 #include <linux/module.h> 13 #include <linux/of.h> 14 #include <linux/platform_device.h> 15 #include <linux/regmap.h> 16 #include <linux/watchdog.h> 17 18 /* WDT timer setting register */ 19 #define WDTTIMSET 0x3004 20 #define WDTTIMSET_PERIOD_MASK (0xf << 0) 21 #define WDTTIMSET_PERIOD_1_SEC (0x3 << 0) 22 23 /* WDT reset selection register */ 24 #define WDTRSTSEL 0x3008 25 #define WDTRSTSEL_RSTSEL_MASK (0x3 << 0) 26 #define WDTRSTSEL_RSTSEL_BOTH (0x0 << 0) 27 #define WDTRSTSEL_RSTSEL_IRQ_ONLY (0x2 << 0) 28 29 /* WDT control register */ 30 #define WDTCTRL 0x300c 31 #define WDTCTRL_STATUS BIT(8) 32 #define WDTCTRL_CLEAR BIT(1) 33 #define WDTCTRL_ENABLE BIT(0) 34 35 #define SEC_TO_WDTTIMSET_PRD(sec) \ 36 (ilog2(sec) + WDTTIMSET_PERIOD_1_SEC) 37 38 #define WDTST_TIMEOUT 1000 /* usec */ 39 40 #define WDT_DEFAULT_TIMEOUT 64 /* Default is 64 seconds */ 41 #define WDT_PERIOD_MIN 1 42 #define WDT_PERIOD_MAX 128 43 44 static unsigned int timeout = 0; 45 static bool nowayout = WATCHDOG_NOWAYOUT; 46 47 struct uniphier_wdt_dev { 48 struct watchdog_device wdt_dev; 49 struct regmap *regmap; 50 }; 51 52 /* 53 * UniPhier Watchdog operations 54 */ 55 static int uniphier_watchdog_ping(struct watchdog_device *w) 56 { 57 struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); 58 unsigned int val; 59 int ret; 60 61 /* Clear counter */ 62 ret = regmap_write_bits(wdev->regmap, WDTCTRL, 63 WDTCTRL_CLEAR, WDTCTRL_CLEAR); 64 if (!ret) 65 /* 66 * As SoC specification, after clear counter, 67 * it needs to wait until counter status is 1. 68 */ 69 ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val, 70 (val & WDTCTRL_STATUS), 71 0, WDTST_TIMEOUT); 72 73 return ret; 74 } 75 76 static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec) 77 { 78 unsigned int val; 79 int ret; 80 81 ret = regmap_read_poll_timeout(regmap, WDTCTRL, val, 82 !(val & WDTCTRL_STATUS), 83 0, WDTST_TIMEOUT); 84 if (ret) 85 return ret; 86 87 /* Setup period */ 88 ret = regmap_write(regmap, WDTTIMSET, 89 SEC_TO_WDTTIMSET_PRD(sec)); 90 if (ret) 91 return ret; 92 93 /* Enable and clear watchdog */ 94 ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR); 95 if (!ret) 96 /* 97 * As SoC specification, after clear counter, 98 * it needs to wait until counter status is 1. 99 */ 100 ret = regmap_read_poll_timeout(regmap, WDTCTRL, val, 101 (val & WDTCTRL_STATUS), 102 0, WDTST_TIMEOUT); 103 104 return ret; 105 } 106 107 static int __uniphier_watchdog_stop(struct regmap *regmap) 108 { 109 /* Disable and stop watchdog */ 110 return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0); 111 } 112 113 static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec) 114 { 115 int ret; 116 117 ret = __uniphier_watchdog_stop(regmap); 118 if (ret) 119 return ret; 120 121 return __uniphier_watchdog_start(regmap, sec); 122 } 123 124 static int uniphier_watchdog_start(struct watchdog_device *w) 125 { 126 struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); 127 unsigned int tmp_timeout; 128 129 tmp_timeout = roundup_pow_of_two(w->timeout); 130 131 return __uniphier_watchdog_start(wdev->regmap, tmp_timeout); 132 } 133 134 static int uniphier_watchdog_stop(struct watchdog_device *w) 135 { 136 struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); 137 138 return __uniphier_watchdog_stop(wdev->regmap); 139 } 140 141 static int uniphier_watchdog_set_timeout(struct watchdog_device *w, 142 unsigned int t) 143 { 144 struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w); 145 unsigned int tmp_timeout; 146 int ret; 147 148 tmp_timeout = roundup_pow_of_two(t); 149 if (tmp_timeout == w->timeout) 150 return 0; 151 152 if (watchdog_active(w)) { 153 ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout); 154 if (ret) 155 return ret; 156 } 157 158 w->timeout = tmp_timeout; 159 160 return 0; 161 } 162 163 /* 164 * Kernel Interfaces 165 */ 166 static const struct watchdog_info uniphier_wdt_info = { 167 .identity = "uniphier-wdt", 168 .options = WDIOF_SETTIMEOUT | 169 WDIOF_KEEPALIVEPING | 170 WDIOF_MAGICCLOSE | 171 WDIOF_OVERHEAT, 172 }; 173 174 static const struct watchdog_ops uniphier_wdt_ops = { 175 .owner = THIS_MODULE, 176 .start = uniphier_watchdog_start, 177 .stop = uniphier_watchdog_stop, 178 .ping = uniphier_watchdog_ping, 179 .set_timeout = uniphier_watchdog_set_timeout, 180 }; 181 182 static int uniphier_wdt_probe(struct platform_device *pdev) 183 { 184 struct device *dev = &pdev->dev; 185 struct uniphier_wdt_dev *wdev; 186 struct regmap *regmap; 187 struct device_node *parent; 188 int ret; 189 190 wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL); 191 if (!wdev) 192 return -ENOMEM; 193 194 parent = of_get_parent(dev->of_node); /* parent should be syscon node */ 195 regmap = syscon_node_to_regmap(parent); 196 of_node_put(parent); 197 if (IS_ERR(regmap)) 198 return PTR_ERR(regmap); 199 200 wdev->regmap = regmap; 201 wdev->wdt_dev.info = &uniphier_wdt_info; 202 wdev->wdt_dev.ops = &uniphier_wdt_ops; 203 wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX; 204 wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN; 205 wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT; 206 wdev->wdt_dev.parent = dev; 207 208 watchdog_init_timeout(&wdev->wdt_dev, timeout, dev); 209 watchdog_set_nowayout(&wdev->wdt_dev, nowayout); 210 watchdog_stop_on_reboot(&wdev->wdt_dev); 211 212 watchdog_set_drvdata(&wdev->wdt_dev, wdev); 213 214 uniphier_watchdog_stop(&wdev->wdt_dev); 215 ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH); 216 if (ret) 217 return ret; 218 219 ret = devm_watchdog_register_device(dev, &wdev->wdt_dev); 220 if (ret) 221 return ret; 222 223 dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n", 224 wdev->wdt_dev.timeout, nowayout); 225 226 return 0; 227 } 228 229 static const struct of_device_id uniphier_wdt_dt_ids[] = { 230 { .compatible = "socionext,uniphier-wdt" }, 231 { /* sentinel */ } 232 }; 233 MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids); 234 235 static struct platform_driver uniphier_wdt_driver = { 236 .probe = uniphier_wdt_probe, 237 .driver = { 238 .name = "uniphier-wdt", 239 .of_match_table = uniphier_wdt_dt_ids, 240 }, 241 }; 242 243 module_platform_driver(uniphier_wdt_driver); 244 245 module_param(timeout, uint, 0000); 246 MODULE_PARM_DESC(timeout, 247 "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default=" 248 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")"); 249 250 module_param(nowayout, bool, 0000); 251 MODULE_PARM_DESC(nowayout, 252 "Watchdog cannot be stopped once started (default=" 253 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); 254 255 MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>"); 256 MODULE_DESCRIPTION("UniPhier Watchdog Device Driver"); 257 MODULE_LICENSE("GPL v2"); 258