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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs4 *5 * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp>6 */7 8#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt9 10#include <linux/module.h>11#include <linux/moduleparam.h>12#include <linux/types.h>13#include <linux/watchdog.h>14#include <linux/init.h>15#include <linux/platform_device.h>16#include <linux/clk.h>17#include <linux/err.h>18#include <linux/io.h>19#include <asm/txx9tmr.h>20 21#define WD_TIMER_CCD 7 /* 1/256 */22#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD))23#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK)24#define TIMER_MARGIN 60 /* Default is 60 seconds */25 26static unsigned int timeout = TIMER_MARGIN; /* in seconds */27module_param(timeout, uint, 0);28MODULE_PARM_DESC(timeout,29 "Watchdog timeout in seconds. "30 "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), "31 "default=" __MODULE_STRING(TIMER_MARGIN) ")");32 33static bool nowayout = WATCHDOG_NOWAYOUT;34module_param(nowayout, bool, 0);35MODULE_PARM_DESC(nowayout,36 "Watchdog cannot be stopped once started "37 "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");38 39static struct txx9_tmr_reg __iomem *txx9wdt_reg;40static struct clk *txx9_imclk;41static DEFINE_SPINLOCK(txx9_lock);42 43static int txx9wdt_ping(struct watchdog_device *wdt_dev)44{45 spin_lock(&txx9_lock);46 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);47 spin_unlock(&txx9_lock);48 return 0;49}50 51static int txx9wdt_start(struct watchdog_device *wdt_dev)52{53 spin_lock(&txx9_lock);54 __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra);55 __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr);56 __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */57 __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG,58 &txx9wdt_reg->tcr);59 __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr);60 spin_unlock(&txx9_lock);61 return 0;62}63 64static int txx9wdt_stop(struct watchdog_device *wdt_dev)65{66 spin_lock(&txx9_lock);67 __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr);68 __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE,69 &txx9wdt_reg->tcr);70 spin_unlock(&txx9_lock);71 return 0;72}73 74static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev,75 unsigned int new_timeout)76{77 wdt_dev->timeout = new_timeout;78 txx9wdt_stop(wdt_dev);79 txx9wdt_start(wdt_dev);80 return 0;81}82 83static const struct watchdog_info txx9wdt_info = {84 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,85 .identity = "Hardware Watchdog for TXx9",86};87 88static const struct watchdog_ops txx9wdt_ops = {89 .owner = THIS_MODULE,90 .start = txx9wdt_start,91 .stop = txx9wdt_stop,92 .ping = txx9wdt_ping,93 .set_timeout = txx9wdt_set_timeout,94};95 96static struct watchdog_device txx9wdt = {97 .info = &txx9wdt_info,98 .ops = &txx9wdt_ops,99};100 101static int txx9wdt_probe(struct platform_device *dev)102{103 int ret;104 105 txx9_imclk = clk_get(NULL, "imbus_clk");106 if (IS_ERR(txx9_imclk)) {107 ret = PTR_ERR(txx9_imclk);108 txx9_imclk = NULL;109 goto exit;110 }111 ret = clk_prepare_enable(txx9_imclk);112 if (ret) {113 clk_put(txx9_imclk);114 txx9_imclk = NULL;115 goto exit;116 }117 118 txx9wdt_reg = devm_platform_ioremap_resource(dev, 0);119 if (IS_ERR(txx9wdt_reg)) {120 ret = PTR_ERR(txx9wdt_reg);121 goto exit;122 }123 124 if (timeout < 1 || timeout > WD_MAX_TIMEOUT)125 timeout = TIMER_MARGIN;126 txx9wdt.timeout = timeout;127 txx9wdt.min_timeout = 1;128 txx9wdt.max_timeout = WD_MAX_TIMEOUT;129 txx9wdt.parent = &dev->dev;130 watchdog_set_nowayout(&txx9wdt, nowayout);131 132 ret = watchdog_register_device(&txx9wdt);133 if (ret)134 goto exit;135 136 pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n",137 timeout, WD_MAX_TIMEOUT, nowayout);138 139 return 0;140exit:141 if (txx9_imclk) {142 clk_disable_unprepare(txx9_imclk);143 clk_put(txx9_imclk);144 }145 return ret;146}147 148static void txx9wdt_remove(struct platform_device *dev)149{150 watchdog_unregister_device(&txx9wdt);151 clk_disable_unprepare(txx9_imclk);152 clk_put(txx9_imclk);153}154 155static void txx9wdt_shutdown(struct platform_device *dev)156{157 txx9wdt_stop(&txx9wdt);158}159 160static struct platform_driver txx9wdt_driver = {161 .probe = txx9wdt_probe,162 .remove_new = txx9wdt_remove,163 .shutdown = txx9wdt_shutdown,164 .driver = {165 .name = "txx9wdt",166 },167};168module_platform_driver(txx9wdt_driver);169 170MODULE_DESCRIPTION("TXx9 Watchdog Driver");171MODULE_LICENSE("GPL");172MODULE_ALIAS("platform:txx9wdt");173