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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * drivers/char/watchdog/ixp4xx_wdt.c4 *5 * Watchdog driver for Intel IXP4xx network processors6 *7 * Author: Deepak Saxena <dsaxena@plexity.net>8 * Author: Linus Walleij <linus.walleij@linaro.org>9 *10 * Copyright 2004 (c) MontaVista, Software, Inc.11 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>12 */13 14#include <linux/module.h>15#include <linux/types.h>16#include <linux/kernel.h>17#include <linux/watchdog.h>18#include <linux/bits.h>19#include <linux/platform_device.h>20#include <linux/clk.h>21#include <linux/soc/ixp4xx/cpu.h>22 23struct ixp4xx_wdt {24 struct watchdog_device wdd;25 void __iomem *base;26 unsigned long rate;27};28 29/* Fallback if we do not have a clock for this */30#define IXP4XX_TIMER_FREQ 6666600031 32/* Registers after the timer registers */33#define IXP4XX_OSWT_OFFSET 0x14 /* Watchdog Timer */34#define IXP4XX_OSWE_OFFSET 0x18 /* Watchdog Enable */35#define IXP4XX_OSWK_OFFSET 0x1C /* Watchdog Key */36#define IXP4XX_OSST_OFFSET 0x20 /* Timer Status */37 38#define IXP4XX_OSST_TIMER_WDOG_PEND 0x0000000839#define IXP4XX_OSST_TIMER_WARM_RESET 0x0000001040#define IXP4XX_WDT_KEY 0x0000482E41#define IXP4XX_WDT_RESET_ENABLE 0x0000000142#define IXP4XX_WDT_IRQ_ENABLE 0x0000000243#define IXP4XX_WDT_COUNT_ENABLE 0x0000000444 45static inline46struct ixp4xx_wdt *to_ixp4xx_wdt(struct watchdog_device *wdd)47{48 return container_of(wdd, struct ixp4xx_wdt, wdd);49}50 51static int ixp4xx_wdt_start(struct watchdog_device *wdd)52{53 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);54 55 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);56 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);57 __raw_writel(wdd->timeout * iwdt->rate,58 iwdt->base + IXP4XX_OSWT_OFFSET);59 __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,60 iwdt->base + IXP4XX_OSWE_OFFSET);61 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);62 63 return 0;64}65 66static int ixp4xx_wdt_stop(struct watchdog_device *wdd)67{68 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);69 70 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);71 __raw_writel(0, iwdt->base + IXP4XX_OSWE_OFFSET);72 __raw_writel(0, iwdt->base + IXP4XX_OSWK_OFFSET);73 74 return 0;75}76 77static int ixp4xx_wdt_set_timeout(struct watchdog_device *wdd,78 unsigned int timeout)79{80 wdd->timeout = timeout;81 if (watchdog_active(wdd))82 ixp4xx_wdt_start(wdd);83 84 return 0;85}86 87static int ixp4xx_wdt_restart(struct watchdog_device *wdd,88 unsigned long action, void *data)89{90 struct ixp4xx_wdt *iwdt = to_ixp4xx_wdt(wdd);91 92 __raw_writel(IXP4XX_WDT_KEY, iwdt->base + IXP4XX_OSWK_OFFSET);93 __raw_writel(0, iwdt->base + IXP4XX_OSWT_OFFSET);94 __raw_writel(IXP4XX_WDT_COUNT_ENABLE | IXP4XX_WDT_RESET_ENABLE,95 iwdt->base + IXP4XX_OSWE_OFFSET);96 97 return 0;98}99 100static const struct watchdog_ops ixp4xx_wdt_ops = {101 .start = ixp4xx_wdt_start,102 .stop = ixp4xx_wdt_stop,103 .set_timeout = ixp4xx_wdt_set_timeout,104 .restart = ixp4xx_wdt_restart,105 .owner = THIS_MODULE,106};107 108/*109 * The A0 version of the IXP422 had a bug in the watchdog making110 * is useless, but we still need to use it to restart the system111 * as it is the only way, so in this special case we register a112 * "dummy" watchdog that doesn't really work, but will support113 * the restart operation.114 */115static int ixp4xx_wdt_dummy(struct watchdog_device *wdd)116{117 return 0;118}119 120static const struct watchdog_ops ixp4xx_wdt_restart_only_ops = {121 .start = ixp4xx_wdt_dummy,122 .stop = ixp4xx_wdt_dummy,123 .restart = ixp4xx_wdt_restart,124 .owner = THIS_MODULE,125};126 127static const struct watchdog_info ixp4xx_wdt_info = {128 .options = WDIOF_KEEPALIVEPING129 | WDIOF_MAGICCLOSE130 | WDIOF_SETTIMEOUT,131 .identity = KBUILD_MODNAME,132};133 134static int ixp4xx_wdt_probe(struct platform_device *pdev)135{136 static const struct watchdog_ops *iwdt_ops;137 struct device *dev = &pdev->dev;138 struct ixp4xx_wdt *iwdt;139 struct clk *clk;140 int ret;141 142 if (!(read_cpuid_id() & 0xf) && !cpu_is_ixp46x()) {143 dev_info(dev, "Rev. A0 IXP42x CPU detected - only restart supported\n");144 iwdt_ops = &ixp4xx_wdt_restart_only_ops;145 } else {146 iwdt_ops = &ixp4xx_wdt_ops;147 }148 149 iwdt = devm_kzalloc(dev, sizeof(*iwdt), GFP_KERNEL);150 if (!iwdt)151 return -ENOMEM;152 iwdt->base = (void __iomem *)dev->platform_data;153 154 /*155 * Retrieve rate from a fixed clock from the device tree if156 * the parent has that, else use the default clock rate.157 */158 clk = devm_clk_get_enabled(dev->parent, NULL);159 if (!IS_ERR(clk))160 iwdt->rate = clk_get_rate(clk);161 162 if (!iwdt->rate)163 iwdt->rate = IXP4XX_TIMER_FREQ;164 165 iwdt->wdd.info = &ixp4xx_wdt_info;166 iwdt->wdd.ops = iwdt_ops;167 iwdt->wdd.min_timeout = 1;168 iwdt->wdd.max_timeout = U32_MAX / iwdt->rate;169 iwdt->wdd.parent = dev;170 /* Default to 60 seconds */171 iwdt->wdd.timeout = 60U;172 watchdog_init_timeout(&iwdt->wdd, 0, dev);173 174 if (__raw_readl(iwdt->base + IXP4XX_OSST_OFFSET) &175 IXP4XX_OSST_TIMER_WARM_RESET)176 iwdt->wdd.bootstatus = WDIOF_CARDRESET;177 178 ret = devm_watchdog_register_device(dev, &iwdt->wdd);179 if (ret)180 return ret;181 182 dev_info(dev, "IXP4xx watchdog available\n");183 184 return 0;185}186 187static struct platform_driver ixp4xx_wdt_driver = {188 .probe = ixp4xx_wdt_probe,189 .driver = {190 .name = "ixp4xx-watchdog",191 },192};193module_platform_driver(ixp4xx_wdt_driver);194 195MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");196MODULE_DESCRIPTION("IXP4xx Network Processor Watchdog");197MODULE_LICENSE("GPL");198