/* * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs * * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/watchdog.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/clk.h> #include <linux/err.h> #include <linux/io.h> #include <asm/txx9tmr.h> #define WD_TIMER_CCD 7 /* 1/256 */ #define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) #define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) #define TIMER_MARGIN 60 /* Default is 60 seconds */ static unsigned int timeout = TIMER_MARGIN; /* in seconds */ module_param(timeout, uint, 0); MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. " "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " "default=" __MODULE_STRING(TIMER_MARGIN) ")"); static bool nowayout = WATCHDOG_NOWAYOUT; module_param(nowayout, bool, 0); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started " "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); static struct txx9_tmr_reg __iomem *txx9wdt_reg; static struct clk *txx9_imclk; static DEFINE_SPINLOCK(txx9_lock); static int txx9wdt_ping(struct watchdog_device *wdt_dev) { spin_lock(&txx9_lock); __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); spin_unlock(&txx9_lock); return 0; } static int txx9wdt_start(struct watchdog_device *wdt_dev) { spin_lock(&txx9_lock); __raw_writel(WD_TIMER_CLK * wdt_dev->timeout, &txx9wdt_reg->cpra); __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, &txx9wdt_reg->tcr); __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); spin_unlock(&txx9_lock); return 0; } static int txx9wdt_stop(struct watchdog_device *wdt_dev) { spin_lock(&txx9_lock); __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, &txx9wdt_reg->tcr); spin_unlock(&txx9_lock); return 0; } static int txx9wdt_set_timeout(struct watchdog_device *wdt_dev, unsigned int new_timeout) { wdt_dev->timeout = new_timeout; txx9wdt_stop(wdt_dev); txx9wdt_start(wdt_dev); return 0; } static const struct watchdog_info txx9wdt_info = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .identity = "Hardware Watchdog for TXx9", }; static const struct watchdog_ops txx9wdt_ops = { .owner = THIS_MODULE, .start = txx9wdt_start, .stop = txx9wdt_stop, .ping = txx9wdt_ping, .set_timeout = txx9wdt_set_timeout, }; static struct watchdog_device txx9wdt = { .info = &txx9wdt_info, .ops = &txx9wdt_ops, }; static int __init txx9wdt_probe(struct platform_device *dev) { struct resource *res; int ret; txx9_imclk = clk_get(NULL, "imbus_clk"); if (IS_ERR(txx9_imclk)) { ret = PTR_ERR(txx9_imclk); txx9_imclk = NULL; goto exit; } ret = clk_prepare_enable(txx9_imclk); if (ret) { clk_put(txx9_imclk); txx9_imclk = NULL; goto exit; } res = platform_get_resource(dev, IORESOURCE_MEM, 0); txx9wdt_reg = devm_ioremap_resource(&dev->dev, res); if (IS_ERR(txx9wdt_reg)) { ret = PTR_ERR(txx9wdt_reg); goto exit; } if (timeout < 1 || timeout > WD_MAX_TIMEOUT) timeout = TIMER_MARGIN; txx9wdt.timeout = timeout; txx9wdt.min_timeout = 1; txx9wdt.max_timeout = WD_MAX_TIMEOUT; txx9wdt.parent = &dev->dev; watchdog_set_nowayout(&txx9wdt, nowayout); ret = watchdog_register_device(&txx9wdt); if (ret) goto exit; pr_info("Hardware Watchdog Timer: timeout=%d sec (max %ld) (nowayout= %d)\n", timeout, WD_MAX_TIMEOUT, nowayout); return 0; exit: if (txx9_imclk) { clk_disable_unprepare(txx9_imclk); clk_put(txx9_imclk); } return ret; } static int __exit txx9wdt_remove(struct platform_device *dev) { watchdog_unregister_device(&txx9wdt); clk_disable_unprepare(txx9_imclk); clk_put(txx9_imclk); return 0; } static void txx9wdt_shutdown(struct platform_device *dev) { txx9wdt_stop(&txx9wdt); } static struct platform_driver txx9wdt_driver = { .remove = __exit_p(txx9wdt_remove), .shutdown = txx9wdt_shutdown, .driver = { .name = "txx9wdt", }, }; module_platform_driver_probe(txx9wdt_driver, txx9wdt_probe); MODULE_DESCRIPTION("TXx9 Watchdog Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:txx9wdt");