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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Meson Watchdog Driver4 *5 * Copyright (c) 2014 Carlo Caione6 */7 8#include <linux/clk.h>9#include <linux/delay.h>10#include <linux/err.h>11#include <linux/init.h>12#include <linux/io.h>13#include <linux/kernel.h>14#include <linux/mod_devicetable.h>15#include <linux/module.h>16#include <linux/moduleparam.h>17#include <linux/platform_device.h>18#include <linux/property.h>19#include <linux/types.h>20#include <linux/watchdog.h>21 22#define DRV_NAME "meson_wdt"23 24#define MESON_WDT_TC 0x0025#define MESON_WDT_DC_RESET (3 << 24)26 27#define MESON_WDT_RESET 0x0428 29#define MESON_WDT_TIMEOUT 3030#define MESON_WDT_MIN_TIMEOUT 131 32#define MESON_SEC_TO_TC(s, c) ((s) * (c))33 34static bool nowayout = WATCHDOG_NOWAYOUT;35static unsigned int timeout;36 37struct meson_wdt_data {38 unsigned int enable;39 unsigned int terminal_count_mask;40 unsigned int count_unit;41};42 43static struct meson_wdt_data meson6_wdt_data = {44 .enable = BIT(22),45 .terminal_count_mask = 0x3fffff,46 .count_unit = 100000, /* 10 us */47};48 49static struct meson_wdt_data meson8b_wdt_data = {50 .enable = BIT(19),51 .terminal_count_mask = 0xffff,52 .count_unit = 7812, /* 128 us */53};54 55struct meson_wdt_dev {56 struct watchdog_device wdt_dev;57 void __iomem *wdt_base;58 const struct meson_wdt_data *data;59};60 61static int meson_wdt_restart(struct watchdog_device *wdt_dev,62 unsigned long action, void *data)63{64 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);65 u32 tc_reboot = MESON_WDT_DC_RESET;66 67 tc_reboot |= meson_wdt->data->enable;68 69 while (1) {70 writel(tc_reboot, meson_wdt->wdt_base + MESON_WDT_TC);71 mdelay(5);72 }73 74 return 0;75}76 77static int meson_wdt_ping(struct watchdog_device *wdt_dev)78{79 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);80 81 writel(0, meson_wdt->wdt_base + MESON_WDT_RESET);82 83 return 0;84}85 86static void meson_wdt_change_timeout(struct watchdog_device *wdt_dev,87 unsigned int timeout)88{89 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);90 u32 reg;91 92 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);93 reg &= ~meson_wdt->data->terminal_count_mask;94 reg |= MESON_SEC_TO_TC(timeout, meson_wdt->data->count_unit);95 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);96}97 98static int meson_wdt_set_timeout(struct watchdog_device *wdt_dev,99 unsigned int timeout)100{101 wdt_dev->timeout = timeout;102 103 meson_wdt_change_timeout(wdt_dev, timeout);104 meson_wdt_ping(wdt_dev);105 106 return 0;107}108 109static int meson_wdt_stop(struct watchdog_device *wdt_dev)110{111 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);112 u32 reg;113 114 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);115 reg &= ~meson_wdt->data->enable;116 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);117 118 return 0;119}120 121static int meson_wdt_start(struct watchdog_device *wdt_dev)122{123 struct meson_wdt_dev *meson_wdt = watchdog_get_drvdata(wdt_dev);124 u32 reg;125 126 meson_wdt_change_timeout(wdt_dev, meson_wdt->wdt_dev.timeout);127 meson_wdt_ping(wdt_dev);128 129 reg = readl(meson_wdt->wdt_base + MESON_WDT_TC);130 reg |= meson_wdt->data->enable;131 writel(reg, meson_wdt->wdt_base + MESON_WDT_TC);132 133 return 0;134}135 136static const struct watchdog_info meson_wdt_info = {137 .identity = DRV_NAME,138 .options = WDIOF_SETTIMEOUT |139 WDIOF_KEEPALIVEPING |140 WDIOF_MAGICCLOSE,141};142 143static const struct watchdog_ops meson_wdt_ops = {144 .owner = THIS_MODULE,145 .start = meson_wdt_start,146 .stop = meson_wdt_stop,147 .ping = meson_wdt_ping,148 .set_timeout = meson_wdt_set_timeout,149 .restart = meson_wdt_restart,150};151 152static const struct of_device_id meson_wdt_dt_ids[] = {153 { .compatible = "amlogic,meson6-wdt", .data = &meson6_wdt_data },154 { .compatible = "amlogic,meson8-wdt", .data = &meson6_wdt_data },155 { .compatible = "amlogic,meson8b-wdt", .data = &meson8b_wdt_data },156 { .compatible = "amlogic,meson8m2-wdt", .data = &meson8b_wdt_data },157 { /* sentinel */ }158};159MODULE_DEVICE_TABLE(of, meson_wdt_dt_ids);160 161static int meson_wdt_probe(struct platform_device *pdev)162{163 struct device *dev = &pdev->dev;164 struct meson_wdt_dev *meson_wdt;165 int err;166 167 meson_wdt = devm_kzalloc(dev, sizeof(*meson_wdt), GFP_KERNEL);168 if (!meson_wdt)169 return -ENOMEM;170 171 meson_wdt->wdt_base = devm_platform_ioremap_resource(pdev, 0);172 if (IS_ERR(meson_wdt->wdt_base))173 return PTR_ERR(meson_wdt->wdt_base);174 175 meson_wdt->data = device_get_match_data(dev);176 177 meson_wdt->wdt_dev.parent = dev;178 meson_wdt->wdt_dev.info = &meson_wdt_info;179 meson_wdt->wdt_dev.ops = &meson_wdt_ops;180 meson_wdt->wdt_dev.max_timeout =181 meson_wdt->data->terminal_count_mask / meson_wdt->data->count_unit;182 meson_wdt->wdt_dev.min_timeout = MESON_WDT_MIN_TIMEOUT;183 meson_wdt->wdt_dev.timeout = min_t(unsigned int,184 MESON_WDT_TIMEOUT,185 meson_wdt->wdt_dev.max_timeout);186 187 watchdog_set_drvdata(&meson_wdt->wdt_dev, meson_wdt);188 189 watchdog_init_timeout(&meson_wdt->wdt_dev, timeout, dev);190 watchdog_set_nowayout(&meson_wdt->wdt_dev, nowayout);191 watchdog_set_restart_priority(&meson_wdt->wdt_dev, 128);192 193 meson_wdt_stop(&meson_wdt->wdt_dev);194 195 watchdog_stop_on_reboot(&meson_wdt->wdt_dev);196 err = devm_watchdog_register_device(dev, &meson_wdt->wdt_dev);197 if (err)198 return err;199 200 dev_info(dev, "Watchdog enabled (timeout=%d sec, nowayout=%d)",201 meson_wdt->wdt_dev.timeout, nowayout);202 203 return 0;204}205 206static struct platform_driver meson_wdt_driver = {207 .probe = meson_wdt_probe,208 .driver = {209 .name = DRV_NAME,210 .of_match_table = meson_wdt_dt_ids,211 },212};213 214module_platform_driver(meson_wdt_driver);215 216module_param(timeout, uint, 0);217MODULE_PARM_DESC(timeout, "Watchdog heartbeat in seconds");218 219module_param(nowayout, bool, 0);220MODULE_PARM_DESC(nowayout,221 "Watchdog cannot be stopped once started (default="222 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");223 224MODULE_LICENSE("GPL");225MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");226MODULE_DESCRIPTION("Meson Watchdog Timer Driver");227