| /* |
| * drivers/watchdog/shwdt.c |
| * |
| * Watchdog driver for integrated watchdog in the SuperH processors. |
| * |
| * Copyright (C) 2001 - 2012 Paul Mundt <lethal@linux-sh.org> |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2 of the License, or (at your |
| * option) any later version. |
| * |
| * 14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com> |
| * Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT |
| * |
| * 19-Apr-2002 Rob Radez <rob@osinvestor.com> |
| * Added expect close support, made emulated timeout runtime changeable |
| * general cleanups, add some ioctls |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/platform_device.h> |
| #include <linux/init.h> |
| #include <linux/types.h> |
| #include <linux/spinlock.h> |
| #include <linux/watchdog.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/slab.h> |
| #include <linux/io.h> |
| #include <linux/clk.h> |
| #include <linux/err.h> |
| #include <asm/watchdog.h> |
| |
| #define DRV_NAME "sh-wdt" |
| |
| /* |
| * Default clock division ratio is 5.25 msecs. For an additional table of |
| * values, consult the asm-sh/watchdog.h. Overload this at module load |
| * time. |
| * |
| * In order for this to work reliably we need to have HZ set to 1000 or |
| * something quite higher than 100 (or we need a proper high-res timer |
| * implementation that will deal with this properly), otherwise the 10ms |
| * resolution of a jiffy is enough to trigger the overflow. For things like |
| * the SH-4 and SH-5, this isn't necessarily that big of a problem, though |
| * for the SH-2 and SH-3, this isn't recommended unless the WDT is absolutely |
| * necssary. |
| * |
| * As a result of this timing problem, the only modes that are particularly |
| * feasible are the 4096 and the 2048 divisors, which yield 5.25 and 2.62ms |
| * overflow periods respectively. |
| * |
| * Also, since we can't really expect userspace to be responsive enough |
| * before the overflow happens, we maintain two separate timers .. One in |
| * the kernel for clearing out WOVF every 2ms or so (again, this depends on |
| * HZ == 1000), and another for monitoring userspace writes to the WDT device. |
| * |
| * As such, we currently use a configurable heartbeat interval which defaults |
| * to 30s. In this case, the userspace daemon is only responsible for periodic |
| * writes to the device before the next heartbeat is scheduled. If the daemon |
| * misses its deadline, the kernel timer will allow the WDT to overflow. |
| */ |
| static int clock_division_ratio = WTCSR_CKS_4096; |
| #define next_ping_period(cks) (jiffies + msecs_to_jiffies(cks - 4)) |
| |
| #define WATCHDOG_HEARTBEAT 30 /* 30 sec default heartbeat */ |
| static int heartbeat = WATCHDOG_HEARTBEAT; /* in seconds */ |
| static bool nowayout = WATCHDOG_NOWAYOUT; |
| static unsigned long next_heartbeat; |
| |
| struct sh_wdt { |
| void __iomem *base; |
| struct device *dev; |
| struct clk *clk; |
| spinlock_t lock; |
| |
| struct timer_list timer; |
| }; |
| |
| static int sh_wdt_start(struct watchdog_device *wdt_dev) |
| { |
| struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev); |
| unsigned long flags; |
| u8 csr; |
| |
| pm_runtime_get_sync(wdt->dev); |
| clk_enable(wdt->clk); |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| |
| next_heartbeat = jiffies + (heartbeat * HZ); |
| mod_timer(&wdt->timer, next_ping_period(clock_division_ratio)); |
| |
| csr = sh_wdt_read_csr(); |
| csr |= WTCSR_WT | clock_division_ratio; |
| sh_wdt_write_csr(csr); |
| |
| sh_wdt_write_cnt(0); |
| |
| /* |
| * These processors have a bit of an inconsistent initialization |
| * process.. starting with SH-3, RSTS was moved to WTCSR, and the |
| * RSTCSR register was removed. |
| * |
| * On the SH-2 however, in addition with bits being in different |
| * locations, we must deal with RSTCSR outright.. |
| */ |
| csr = sh_wdt_read_csr(); |
| csr |= WTCSR_TME; |
| csr &= ~WTCSR_RSTS; |
| sh_wdt_write_csr(csr); |
| |
| #ifdef CONFIG_CPU_SH2 |
| csr = sh_wdt_read_rstcsr(); |
| csr &= ~RSTCSR_RSTS; |
| sh_wdt_write_rstcsr(csr); |
| #endif |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| return 0; |
| } |
| |
| static int sh_wdt_stop(struct watchdog_device *wdt_dev) |
| { |
| struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev); |
| unsigned long flags; |
| u8 csr; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| |
| del_timer(&wdt->timer); |
| |
| csr = sh_wdt_read_csr(); |
| csr &= ~WTCSR_TME; |
| sh_wdt_write_csr(csr); |
| |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| clk_disable(wdt->clk); |
| pm_runtime_put_sync(wdt->dev); |
| |
| return 0; |
| } |
| |
| static int sh_wdt_keepalive(struct watchdog_device *wdt_dev) |
| { |
| struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| next_heartbeat = jiffies + (heartbeat * HZ); |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| return 0; |
| } |
| |
| static int sh_wdt_set_heartbeat(struct watchdog_device *wdt_dev, unsigned t) |
| { |
| struct sh_wdt *wdt = watchdog_get_drvdata(wdt_dev); |
| unsigned long flags; |
| |
| if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */ |
| return -EINVAL; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| heartbeat = t; |
| wdt_dev->timeout = t; |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| |
| return 0; |
| } |
| |
| static void sh_wdt_ping(struct timer_list *t) |
| { |
| struct sh_wdt *wdt = from_timer(wdt, t, timer); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&wdt->lock, flags); |
| if (time_before(jiffies, next_heartbeat)) { |
| u8 csr; |
| |
| csr = sh_wdt_read_csr(); |
| csr &= ~WTCSR_IOVF; |
| sh_wdt_write_csr(csr); |
| |
| sh_wdt_write_cnt(0); |
| |
| mod_timer(&wdt->timer, next_ping_period(clock_division_ratio)); |
| } else |
| dev_warn(wdt->dev, "Heartbeat lost! Will not ping " |
| "the watchdog\n"); |
| spin_unlock_irqrestore(&wdt->lock, flags); |
| } |
| |
| static const struct watchdog_info sh_wdt_info = { |
| .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | |
| WDIOF_MAGICCLOSE, |
| .firmware_version = 1, |
| .identity = "SH WDT", |
| }; |
| |
| static const struct watchdog_ops sh_wdt_ops = { |
| .owner = THIS_MODULE, |
| .start = sh_wdt_start, |
| .stop = sh_wdt_stop, |
| .ping = sh_wdt_keepalive, |
| .set_timeout = sh_wdt_set_heartbeat, |
| }; |
| |
| static struct watchdog_device sh_wdt_dev = { |
| .info = &sh_wdt_info, |
| .ops = &sh_wdt_ops, |
| }; |
| |
| static int sh_wdt_probe(struct platform_device *pdev) |
| { |
| struct sh_wdt *wdt; |
| struct resource *res; |
| int rc; |
| |
| /* |
| * As this driver only covers the global watchdog case, reject |
| * any attempts to register per-CPU watchdogs. |
| */ |
| if (pdev->id != -1) |
| return -EINVAL; |
| |
| wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL); |
| if (unlikely(!wdt)) |
| return -ENOMEM; |
| |
| wdt->dev = &pdev->dev; |
| |
| wdt->clk = devm_clk_get(&pdev->dev, NULL); |
| if (IS_ERR(wdt->clk)) { |
| /* |
| * Clock framework support is optional, continue on |
| * anyways if we don't find a matching clock. |
| */ |
| wdt->clk = NULL; |
| } |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| wdt->base = devm_ioremap_resource(wdt->dev, res); |
| if (IS_ERR(wdt->base)) |
| return PTR_ERR(wdt->base); |
| |
| watchdog_set_nowayout(&sh_wdt_dev, nowayout); |
| watchdog_set_drvdata(&sh_wdt_dev, wdt); |
| sh_wdt_dev.parent = &pdev->dev; |
| |
| spin_lock_init(&wdt->lock); |
| |
| rc = sh_wdt_set_heartbeat(&sh_wdt_dev, heartbeat); |
| if (unlikely(rc)) { |
| /* Default timeout if invalid */ |
| sh_wdt_set_heartbeat(&sh_wdt_dev, WATCHDOG_HEARTBEAT); |
| |
| dev_warn(&pdev->dev, |
| "heartbeat value must be 1<=x<=3600, using %d\n", |
| sh_wdt_dev.timeout); |
| } |
| |
| dev_info(&pdev->dev, "configured with heartbeat=%d sec (nowayout=%d)\n", |
| sh_wdt_dev.timeout, nowayout); |
| |
| rc = watchdog_register_device(&sh_wdt_dev); |
| if (unlikely(rc)) { |
| dev_err(&pdev->dev, "Can't register watchdog (err=%d)\n", rc); |
| return rc; |
| } |
| |
| timer_setup(&wdt->timer, sh_wdt_ping, 0); |
| wdt->timer.expires = next_ping_period(clock_division_ratio); |
| |
| dev_info(&pdev->dev, "initialized.\n"); |
| |
| pm_runtime_enable(&pdev->dev); |
| |
| return 0; |
| } |
| |
| static int sh_wdt_remove(struct platform_device *pdev) |
| { |
| watchdog_unregister_device(&sh_wdt_dev); |
| |
| pm_runtime_disable(&pdev->dev); |
| |
| return 0; |
| } |
| |
| static void sh_wdt_shutdown(struct platform_device *pdev) |
| { |
| sh_wdt_stop(&sh_wdt_dev); |
| } |
| |
| static struct platform_driver sh_wdt_driver = { |
| .driver = { |
| .name = DRV_NAME, |
| }, |
| |
| .probe = sh_wdt_probe, |
| .remove = sh_wdt_remove, |
| .shutdown = sh_wdt_shutdown, |
| }; |
| |
| static int __init sh_wdt_init(void) |
| { |
| if (unlikely(clock_division_ratio < 0x5 || |
| clock_division_ratio > 0x7)) { |
| clock_division_ratio = WTCSR_CKS_4096; |
| |
| pr_info("divisor must be 0x5<=x<=0x7, using %d\n", |
| clock_division_ratio); |
| } |
| |
| return platform_driver_register(&sh_wdt_driver); |
| } |
| |
| static void __exit sh_wdt_exit(void) |
| { |
| platform_driver_unregister(&sh_wdt_driver); |
| } |
| module_init(sh_wdt_init); |
| module_exit(sh_wdt_exit); |
| |
| MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>"); |
| MODULE_DESCRIPTION("SuperH watchdog driver"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("platform:" DRV_NAME); |
| |
| module_param(clock_division_ratio, int, 0); |
| MODULE_PARM_DESC(clock_division_ratio, |
| "Clock division ratio. Valid ranges are from 0x5 (1.31ms) " |
| "to 0x7 (5.25ms). (default=" __MODULE_STRING(WTCSR_CKS_4096) ")"); |
| |
| module_param(heartbeat, int, 0); |
| MODULE_PARM_DESC(heartbeat, |
| "Watchdog heartbeat in seconds. (1 <= heartbeat <= 3600, default=" |
| __MODULE_STRING(WATCHDOG_HEARTBEAT) ")"); |
| |
| module_param(nowayout, bool, 0); |
| MODULE_PARM_DESC(nowayout, |
| "Watchdog cannot be stopped once started (default=" |
| __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |