diff options
Diffstat (limited to 'drivers/watchdog/txx9wdt.c')
| -rw-r--r-- | drivers/watchdog/txx9wdt.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c new file mode 100644 index 00000000..98e16373 --- /dev/null +++ b/drivers/watchdog/txx9wdt.c @@ -0,0 +1,191 @@ +/* + * 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/miscdevice.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_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_request_and_ioremap(&dev->dev, res); + if (!txx9wdt_reg) { + ret = -EBUSY; + 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; + 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(txx9_imclk); + clk_put(txx9_imclk); + } + return ret; +} + +static int __exit txx9wdt_remove(struct platform_device *dev) +{ + watchdog_unregister_device(&txx9wdt); + clk_disable(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", + .owner = THIS_MODULE, + }, +}; + +static int __init watchdog_init(void) +{ + return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe); +} + +static void __exit watchdog_exit(void) +{ + platform_driver_unregister(&txx9wdt_driver); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_DESCRIPTION("TXx9 Watchdog Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:txx9wdt"); |