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author | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
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committer | Srikant Patnaik | 2015-01-11 12:28:04 +0530 |
commit | 871480933a1c28f8a9fed4c4d34d06c439a7a422 (patch) | |
tree | 8718f573808810c2a1e8cb8fb6ac469093ca2784 /drivers/watchdog/shwdt.c | |
parent | 9d40ac5867b9aefe0722bc1f110b965ff294d30d (diff) | |
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Moved, renamed, and deleted files
The original directory structure was scattered and unorganized.
Changes are basically to make it look like kernel structure.
Diffstat (limited to 'drivers/watchdog/shwdt.c')
-rw-r--r-- | drivers/watchdog/shwdt.c | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/drivers/watchdog/shwdt.c b/drivers/watchdog/shwdt.c new file mode 100644 index 00000000..93958a77 --- /dev/null +++ b/drivers/watchdog/shwdt.c @@ -0,0 +1,490 @@ +/* + * drivers/watchdog/shwdt.c + * + * Watchdog driver for integrated watchdog in the SuperH processors. + * + * Copyright (C) 2001 - 2010 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/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/reboot.h> +#include <linux/notifier.h> +#include <linux/ioport.h> +#include <linux/fs.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/io.h> +#include <linux/uaccess.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)) + +static const struct watchdog_info sh_wdt_info; +static struct platform_device *sh_wdt_dev; +static DEFINE_SPINLOCK(shwdt_lock); + +#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 timer_list timer; + + unsigned long enabled; + char expect_close; +}; + +static void sh_wdt_start(struct sh_wdt *wdt) +{ + unsigned long flags; + u8 csr; + + spin_lock_irqsave(&shwdt_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(&shwdt_lock, flags); +} + +static void sh_wdt_stop(struct sh_wdt *wdt) +{ + unsigned long flags; + u8 csr; + + spin_lock_irqsave(&shwdt_lock, flags); + + del_timer(&wdt->timer); + + csr = sh_wdt_read_csr(); + csr &= ~WTCSR_TME; + sh_wdt_write_csr(csr); + + spin_unlock_irqrestore(&shwdt_lock, flags); +} + +static inline void sh_wdt_keepalive(struct sh_wdt *wdt) +{ + unsigned long flags; + + spin_lock_irqsave(&shwdt_lock, flags); + next_heartbeat = jiffies + (heartbeat * HZ); + spin_unlock_irqrestore(&shwdt_lock, flags); +} + +static int sh_wdt_set_heartbeat(int t) +{ + unsigned long flags; + + if (unlikely(t < 1 || t > 3600)) /* arbitrary upper limit */ + return -EINVAL; + + spin_lock_irqsave(&shwdt_lock, flags); + heartbeat = t; + spin_unlock_irqrestore(&shwdt_lock, flags); + return 0; +} + +static void sh_wdt_ping(unsigned long data) +{ + struct sh_wdt *wdt = (struct sh_wdt *)data; + unsigned long flags; + + spin_lock_irqsave(&shwdt_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(&shwdt_lock, flags); +} + +static int sh_wdt_open(struct inode *inode, struct file *file) +{ + struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev); + + if (test_and_set_bit(0, &wdt->enabled)) + return -EBUSY; + if (nowayout) + __module_get(THIS_MODULE); + + file->private_data = wdt; + + sh_wdt_start(wdt); + + return nonseekable_open(inode, file); +} + +static int sh_wdt_close(struct inode *inode, struct file *file) +{ + struct sh_wdt *wdt = file->private_data; + + if (wdt->expect_close == 42) { + sh_wdt_stop(wdt); + } else { + dev_crit(wdt->dev, "Unexpected close, not " + "stopping watchdog!\n"); + sh_wdt_keepalive(wdt); + } + + clear_bit(0, &wdt->enabled); + wdt->expect_close = 0; + + return 0; +} + +static ssize_t sh_wdt_write(struct file *file, const char *buf, + size_t count, loff_t *ppos) +{ + struct sh_wdt *wdt = file->private_data; + + if (count) { + if (!nowayout) { + size_t i; + + wdt->expect_close = 0; + + for (i = 0; i != count; i++) { + char c; + if (get_user(c, buf + i)) + return -EFAULT; + if (c == 'V') + wdt->expect_close = 42; + } + } + sh_wdt_keepalive(wdt); + } + + return count; +} + +static long sh_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + struct sh_wdt *wdt = file->private_data; + int new_heartbeat; + int options, retval = -EINVAL; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user((struct watchdog_info *)arg, + &sh_wdt_info, sizeof(sh_wdt_info)) ? -EFAULT : 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, (int *)arg); + case WDIOC_SETOPTIONS: + if (get_user(options, (int *)arg)) + return -EFAULT; + + if (options & WDIOS_DISABLECARD) { + sh_wdt_stop(wdt); + retval = 0; + } + + if (options & WDIOS_ENABLECARD) { + sh_wdt_start(wdt); + retval = 0; + } + + return retval; + case WDIOC_KEEPALIVE: + sh_wdt_keepalive(wdt); + return 0; + case WDIOC_SETTIMEOUT: + if (get_user(new_heartbeat, (int *)arg)) + return -EFAULT; + + if (sh_wdt_set_heartbeat(new_heartbeat)) + return -EINVAL; + + sh_wdt_keepalive(wdt); + /* Fall */ + case WDIOC_GETTIMEOUT: + return put_user(heartbeat, (int *)arg); + default: + return -ENOTTY; + } + return 0; +} + +static int sh_wdt_notify_sys(struct notifier_block *this, + unsigned long code, void *unused) +{ + struct sh_wdt *wdt = platform_get_drvdata(sh_wdt_dev); + + if (code == SYS_DOWN || code == SYS_HALT) + sh_wdt_stop(wdt); + + return NOTIFY_DONE; +} + +static const struct file_operations sh_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = sh_wdt_write, + .unlocked_ioctl = sh_wdt_ioctl, + .open = sh_wdt_open, + .release = sh_wdt_close, +}; + +static const struct watchdog_info sh_wdt_info = { + .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | + WDIOF_MAGICCLOSE, + .firmware_version = 1, + .identity = "SH WDT", +}; + +static struct notifier_block sh_wdt_notifier = { + .notifier_call = sh_wdt_notify_sys, +}; + +static struct miscdevice sh_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &sh_wdt_fops, +}; + +static int __devinit 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; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (unlikely(!res)) + return -EINVAL; + + if (!devm_request_mem_region(&pdev->dev, res->start, + resource_size(res), DRV_NAME)) + return -EBUSY; + + wdt = devm_kzalloc(&pdev->dev, sizeof(struct sh_wdt), GFP_KERNEL); + if (unlikely(!wdt)) { + rc = -ENOMEM; + goto out_release; + } + + wdt->dev = &pdev->dev; + + wdt->base = devm_ioremap(&pdev->dev, res->start, resource_size(res)); + if (unlikely(!wdt->base)) { + rc = -ENXIO; + goto out_err; + } + + rc = register_reboot_notifier(&sh_wdt_notifier); + if (unlikely(rc)) { + dev_err(&pdev->dev, + "Can't register reboot notifier (err=%d)\n", rc); + goto out_unmap; + } + + sh_wdt_miscdev.parent = wdt->dev; + + rc = misc_register(&sh_wdt_miscdev); + if (unlikely(rc)) { + dev_err(&pdev->dev, + "Can't register miscdev on minor=%d (err=%d)\n", + sh_wdt_miscdev.minor, rc); + goto out_unreg; + } + + init_timer(&wdt->timer); + wdt->timer.function = sh_wdt_ping; + wdt->timer.data = (unsigned long)wdt; + wdt->timer.expires = next_ping_period(clock_division_ratio); + + platform_set_drvdata(pdev, wdt); + sh_wdt_dev = pdev; + + dev_info(&pdev->dev, "initialized.\n"); + + return 0; + +out_unreg: + unregister_reboot_notifier(&sh_wdt_notifier); +out_unmap: + devm_iounmap(&pdev->dev, wdt->base); +out_err: + devm_kfree(&pdev->dev, wdt); +out_release: + devm_release_mem_region(&pdev->dev, res->start, resource_size(res)); + + return rc; +} + +static int __devexit sh_wdt_remove(struct platform_device *pdev) +{ + struct sh_wdt *wdt = platform_get_drvdata(pdev); + struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + + platform_set_drvdata(pdev, NULL); + + misc_deregister(&sh_wdt_miscdev); + + sh_wdt_dev = NULL; + + unregister_reboot_notifier(&sh_wdt_notifier); + devm_release_mem_region(&pdev->dev, res->start, resource_size(res)); + devm_iounmap(&pdev->dev, wdt->base); + devm_kfree(&pdev->dev, wdt); + + return 0; +} + +static struct platform_driver sh_wdt_driver = { + .driver = { + .name = DRV_NAME, + .owner = THIS_MODULE, + }, + + .probe = sh_wdt_probe, + .remove = __devexit_p(sh_wdt_remove), +}; + +static int __init sh_wdt_init(void) +{ + int rc; + + 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); + } + + rc = sh_wdt_set_heartbeat(heartbeat); + if (unlikely(rc)) { + heartbeat = WATCHDOG_HEARTBEAT; + + pr_info("heartbeat value must be 1<=x<=3600, using %d\n", + heartbeat); + } + + pr_info("configured with heartbeat=%d sec (nowayout=%d)\n", + heartbeat, nowayout); + + 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_ALIAS_MISCDEV(WATCHDOG_MINOR); + +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) ")"); |