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1// SPDX-License-Identifier: GPL-2.0+2/*3 * Copyright (C) 2015 Broadcom Corporation4 *5 */6 7#include <linux/clk.h>8#include <linux/init.h>9#include <linux/io.h>10#include <linux/module.h>11#include <linux/of.h>12#include <linux/platform_device.h>13#include <linux/platform_data/bcm7038_wdt.h>14#include <linux/pm.h>15#include <linux/watchdog.h>16 17#define WDT_START_1 0xff0018#define WDT_START_2 0x00ff19#define WDT_STOP_1 0xee0020#define WDT_STOP_2 0x00ee21 22#define WDT_TIMEOUT_REG 0x023#define WDT_CMD_REG 0x424 25#define WDT_MIN_TIMEOUT 1 /* seconds */26#define WDT_DEFAULT_TIMEOUT 30 /* seconds */27#define WDT_DEFAULT_RATE 2700000028 29struct bcm7038_watchdog {30 void __iomem *base;31 struct watchdog_device wdd;32 u32 rate;33 struct clk *clk;34};35 36static bool nowayout = WATCHDOG_NOWAYOUT;37 38static inline void bcm7038_wdt_write(u32 value, void __iomem *addr)39{40 /* MIPS chips strapped for BE will automagically configure the41 * peripheral registers for CPU-native byte order.42 */43 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))44 __raw_writel(value, addr);45 else46 writel_relaxed(value, addr);47}48 49static inline u32 bcm7038_wdt_read(void __iomem *addr)50{51 if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))52 return __raw_readl(addr);53 else54 return readl_relaxed(addr);55}56 57static void bcm7038_wdt_set_timeout_reg(struct watchdog_device *wdog)58{59 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);60 u32 timeout;61 62 timeout = wdt->rate * wdog->timeout;63 64 bcm7038_wdt_write(timeout, wdt->base + WDT_TIMEOUT_REG);65}66 67static int bcm7038_wdt_ping(struct watchdog_device *wdog)68{69 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);70 71 bcm7038_wdt_write(WDT_START_1, wdt->base + WDT_CMD_REG);72 bcm7038_wdt_write(WDT_START_2, wdt->base + WDT_CMD_REG);73 74 return 0;75}76 77static int bcm7038_wdt_start(struct watchdog_device *wdog)78{79 bcm7038_wdt_set_timeout_reg(wdog);80 bcm7038_wdt_ping(wdog);81 82 return 0;83}84 85static int bcm7038_wdt_stop(struct watchdog_device *wdog)86{87 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);88 89 bcm7038_wdt_write(WDT_STOP_1, wdt->base + WDT_CMD_REG);90 bcm7038_wdt_write(WDT_STOP_2, wdt->base + WDT_CMD_REG);91 92 return 0;93}94 95static int bcm7038_wdt_set_timeout(struct watchdog_device *wdog,96 unsigned int t)97{98 /* Can't modify timeout value if watchdog timer is running */99 bcm7038_wdt_stop(wdog);100 wdog->timeout = t;101 bcm7038_wdt_start(wdog);102 103 return 0;104}105 106static unsigned int bcm7038_wdt_get_timeleft(struct watchdog_device *wdog)107{108 struct bcm7038_watchdog *wdt = watchdog_get_drvdata(wdog);109 u32 time_left;110 111 time_left = bcm7038_wdt_read(wdt->base + WDT_CMD_REG);112 113 return time_left / wdt->rate;114}115 116static const struct watchdog_info bcm7038_wdt_info = {117 .identity = "Broadcom BCM7038 Watchdog Timer",118 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |119 WDIOF_MAGICCLOSE120};121 122static const struct watchdog_ops bcm7038_wdt_ops = {123 .owner = THIS_MODULE,124 .start = bcm7038_wdt_start,125 .stop = bcm7038_wdt_stop,126 .set_timeout = bcm7038_wdt_set_timeout,127 .get_timeleft = bcm7038_wdt_get_timeleft,128};129 130static int bcm7038_wdt_probe(struct platform_device *pdev)131{132 struct bcm7038_wdt_platform_data *pdata = pdev->dev.platform_data;133 struct device *dev = &pdev->dev;134 struct bcm7038_watchdog *wdt;135 const char *clk_name = NULL;136 int err;137 138 wdt = devm_kzalloc(dev, sizeof(*wdt), GFP_KERNEL);139 if (!wdt)140 return -ENOMEM;141 142 platform_set_drvdata(pdev, wdt);143 144 wdt->base = devm_platform_ioremap_resource(pdev, 0);145 if (IS_ERR(wdt->base))146 return PTR_ERR(wdt->base);147 148 if (pdata && pdata->clk_name)149 clk_name = pdata->clk_name;150 151 wdt->clk = devm_clk_get_enabled(dev, clk_name);152 /* If unable to get clock, use default frequency */153 if (!IS_ERR(wdt->clk)) {154 wdt->rate = clk_get_rate(wdt->clk);155 /* Prevent divide-by-zero exception */156 if (!wdt->rate)157 wdt->rate = WDT_DEFAULT_RATE;158 } else {159 wdt->rate = WDT_DEFAULT_RATE;160 wdt->clk = NULL;161 }162 163 wdt->wdd.info = &bcm7038_wdt_info;164 wdt->wdd.ops = &bcm7038_wdt_ops;165 wdt->wdd.min_timeout = WDT_MIN_TIMEOUT;166 wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;167 wdt->wdd.max_timeout = 0xffffffff / wdt->rate;168 wdt->wdd.parent = dev;169 watchdog_set_drvdata(&wdt->wdd, wdt);170 171 watchdog_stop_on_reboot(&wdt->wdd);172 watchdog_stop_on_unregister(&wdt->wdd);173 err = devm_watchdog_register_device(dev, &wdt->wdd);174 if (err)175 return err;176 177 dev_info(dev, "Registered BCM7038 Watchdog\n");178 179 return 0;180}181 182static int bcm7038_wdt_suspend(struct device *dev)183{184 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);185 186 if (watchdog_active(&wdt->wdd))187 return bcm7038_wdt_stop(&wdt->wdd);188 189 return 0;190}191 192static int bcm7038_wdt_resume(struct device *dev)193{194 struct bcm7038_watchdog *wdt = dev_get_drvdata(dev);195 196 if (watchdog_active(&wdt->wdd))197 return bcm7038_wdt_start(&wdt->wdd);198 199 return 0;200}201 202static DEFINE_SIMPLE_DEV_PM_OPS(bcm7038_wdt_pm_ops,203 bcm7038_wdt_suspend, bcm7038_wdt_resume);204 205static const struct of_device_id bcm7038_wdt_match[] = {206 { .compatible = "brcm,bcm6345-wdt" },207 { .compatible = "brcm,bcm7038-wdt" },208 {},209};210MODULE_DEVICE_TABLE(of, bcm7038_wdt_match);211 212static const struct platform_device_id bcm7038_wdt_devtype[] = {213 { .name = "bcm63xx-wdt" },214 { /* sentinel */ },215};216MODULE_DEVICE_TABLE(platform, bcm7038_wdt_devtype);217 218static struct platform_driver bcm7038_wdt_driver = {219 .probe = bcm7038_wdt_probe,220 .id_table = bcm7038_wdt_devtype,221 .driver = {222 .name = "bcm7038-wdt",223 .of_match_table = bcm7038_wdt_match,224 .pm = pm_sleep_ptr(&bcm7038_wdt_pm_ops),225 }226};227module_platform_driver(bcm7038_wdt_driver);228 229module_param(nowayout, bool, 0);230MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="231 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");232MODULE_LICENSE("GPL");233MODULE_DESCRIPTION("Driver for Broadcom 7038 SoCs Watchdog");234MODULE_AUTHOR("Justin Chen");235