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1// SPDX-License-Identifier: GPL-2.02/*3 * Watchdog driver for the UniPhier watchdog timer4 *5 * (c) Copyright 2014 Panasonic Corporation6 * (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 0x300420#define WDTTIMSET_PERIOD_MASK (0xf << 0)21#define WDTTIMSET_PERIOD_1_SEC (0x3 << 0)22 23/* WDT reset selection register */24#define WDTRSTSEL 0x300825#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 0x300c31#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 142#define WDT_PERIOD_MAX 12843 44static unsigned int timeout = 0;45static bool nowayout = WATCHDOG_NOWAYOUT;46 47struct uniphier_wdt_dev {48 struct watchdog_device wdt_dev;49 struct regmap *regmap;50};51 52/*53 * UniPhier Watchdog operations54 */55static 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 76static 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 107static 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 113static 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 124static 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 134static 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 141static 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 Interfaces165 */166static 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 174static 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 182static 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 229static const struct of_device_id uniphier_wdt_dt_ids[] = {230 { .compatible = "socionext,uniphier-wdt" },231 { /* sentinel */ }232};233MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);234 235static 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 243module_platform_driver(uniphier_wdt_driver);244 245module_param(timeout, uint, 0000);246MODULE_PARM_DESC(timeout,247 "Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="248 __MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");249 250module_param(nowayout, bool, 0000);251MODULE_PARM_DESC(nowayout,252 "Watchdog cannot be stopped once started (default="253 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");254 255MODULE_AUTHOR("Keiji Hayashibara <hayashibara.keiji@socionext.com>");256MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");257MODULE_LICENSE("GPL v2");258