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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Ralink RT288x/RT3xxx/MT76xx built-in hardware watchdog timer4 *5 * Copyright (C) 2011 Gabor Juhos <juhosg@openwrt.org>6 * Copyright (C) 2013 John Crispin <john@phrozen.org>7 *8 * This driver was based on: drivers/watchdog/softdog.c9 */10 11#include <linux/clk.h>12#include <linux/reset.h>13#include <linux/module.h>14#include <linux/kernel.h>15#include <linux/watchdog.h>16#include <linux/moduleparam.h>17#include <linux/platform_device.h>18#include <linux/mod_devicetable.h>19 20#include <asm/mach-ralink/ralink_regs.h>21 22#define SYSC_RSTSTAT 0x3823#define WDT_RST_CAUSE BIT(1)24 25#define RALINK_WDT_TIMEOUT 3026#define RALINK_WDT_PRESCALE 6553627 28#define TIMER_REG_TMR1LOAD 0x0029#define TIMER_REG_TMR1CTL 0x0830 31#define TMRSTAT_TMR1RST BIT(5)32 33#define TMR1CTL_ENABLE BIT(7)34#define TMR1CTL_MODE_SHIFT 435#define TMR1CTL_MODE_MASK 0x336#define TMR1CTL_MODE_FREE_RUNNING 0x037#define TMR1CTL_MODE_PERIODIC 0x138#define TMR1CTL_MODE_TIMEOUT 0x239#define TMR1CTL_MODE_WDT 0x340#define TMR1CTL_PRESCALE_MASK 0xf41#define TMR1CTL_PRESCALE_65536 0xf42 43struct rt2880_wdt_data {44 void __iomem *base;45 unsigned long freq;46 struct clk *clk;47 struct reset_control *rst;48 struct watchdog_device wdt;49};50 51static bool nowayout = WATCHDOG_NOWAYOUT;52module_param(nowayout, bool, 0);53MODULE_PARM_DESC(nowayout,54 "Watchdog cannot be stopped once started (default="55 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");56 57static inline void rt_wdt_w32(void __iomem *base, unsigned int reg, u32 val)58{59 iowrite32(val, base + reg);60}61 62static inline u32 rt_wdt_r32(void __iomem *base, unsigned int reg)63{64 return ioread32(base + reg);65}66 67static int rt288x_wdt_ping(struct watchdog_device *w)68{69 struct rt2880_wdt_data *drvdata = watchdog_get_drvdata(w);70 71 rt_wdt_w32(drvdata->base, TIMER_REG_TMR1LOAD, w->timeout * drvdata->freq);72 73 return 0;74}75 76static int rt288x_wdt_start(struct watchdog_device *w)77{78 struct rt2880_wdt_data *drvdata = watchdog_get_drvdata(w);79 u32 t;80 81 t = rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL);82 t &= ~(TMR1CTL_MODE_MASK << TMR1CTL_MODE_SHIFT |83 TMR1CTL_PRESCALE_MASK);84 t |= (TMR1CTL_MODE_WDT << TMR1CTL_MODE_SHIFT |85 TMR1CTL_PRESCALE_65536);86 rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, t);87 88 rt288x_wdt_ping(w);89 90 t = rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL);91 t |= TMR1CTL_ENABLE;92 rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, t);93 94 return 0;95}96 97static int rt288x_wdt_stop(struct watchdog_device *w)98{99 struct rt2880_wdt_data *drvdata = watchdog_get_drvdata(w);100 u32 t;101 102 rt288x_wdt_ping(w);103 104 t = rt_wdt_r32(drvdata->base, TIMER_REG_TMR1CTL);105 t &= ~TMR1CTL_ENABLE;106 rt_wdt_w32(drvdata->base, TIMER_REG_TMR1CTL, t);107 108 return 0;109}110 111static int rt288x_wdt_set_timeout(struct watchdog_device *w, unsigned int t)112{113 w->timeout = t;114 rt288x_wdt_ping(w);115 116 return 0;117}118 119static int rt288x_wdt_bootcause(void)120{121 if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)122 return WDIOF_CARDRESET;123 124 return 0;125}126 127static const struct watchdog_info rt288x_wdt_info = {128 .identity = "Ralink Watchdog",129 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,130};131 132static const struct watchdog_ops rt288x_wdt_ops = {133 .owner = THIS_MODULE,134 .start = rt288x_wdt_start,135 .stop = rt288x_wdt_stop,136 .ping = rt288x_wdt_ping,137 .set_timeout = rt288x_wdt_set_timeout,138};139 140static int rt288x_wdt_probe(struct platform_device *pdev)141{142 struct device *dev = &pdev->dev;143 struct watchdog_device *wdt;144 struct rt2880_wdt_data *drvdata;145 int ret;146 147 drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);148 if (!drvdata)149 return -ENOMEM;150 151 drvdata->base = devm_platform_ioremap_resource(pdev, 0);152 if (IS_ERR(drvdata->base))153 return PTR_ERR(drvdata->base);154 155 drvdata->clk = devm_clk_get(dev, NULL);156 if (IS_ERR(drvdata->clk))157 return PTR_ERR(drvdata->clk);158 159 drvdata->rst = devm_reset_control_get_exclusive(dev, NULL);160 if (!IS_ERR(drvdata->rst))161 reset_control_deassert(drvdata->rst);162 163 drvdata->freq = clk_get_rate(drvdata->clk) / RALINK_WDT_PRESCALE;164 165 wdt = &drvdata->wdt;166 wdt->info = &rt288x_wdt_info;167 wdt->ops = &rt288x_wdt_ops;168 wdt->min_timeout = 1;169 wdt->max_timeout = (0xfffful / drvdata->freq);170 wdt->parent = dev;171 wdt->bootstatus = rt288x_wdt_bootcause();172 173 watchdog_init_timeout(wdt, wdt->max_timeout, dev);174 watchdog_set_nowayout(wdt, nowayout);175 watchdog_set_drvdata(wdt, drvdata);176 177 watchdog_stop_on_reboot(wdt);178 ret = devm_watchdog_register_device(dev, &drvdata->wdt);179 if (!ret)180 dev_info(dev, "Initialized\n");181 182 return 0;183}184 185static const struct of_device_id rt288x_wdt_match[] = {186 { .compatible = "ralink,rt2880-wdt" },187 {},188};189MODULE_DEVICE_TABLE(of, rt288x_wdt_match);190 191static struct platform_driver rt288x_wdt_driver = {192 .probe = rt288x_wdt_probe,193 .driver = {194 .name = KBUILD_MODNAME,195 .of_match_table = rt288x_wdt_match,196 },197};198 199module_platform_driver(rt288x_wdt_driver);200 201MODULE_DESCRIPTION("MediaTek/Ralink RT288x/RT3xxx hardware watchdog driver");202MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org");203MODULE_LICENSE("GPL v2");204