diff options
Diffstat (limited to 'drivers/watchdog/mpc8xxx_wdt.c')
| -rw-r--r-- | drivers/watchdog/mpc8xxx_wdt.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/drivers/watchdog/mpc8xxx_wdt.c b/drivers/watchdog/mpc8xxx_wdt.c new file mode 100644 index 00000000..40f7bf1f --- /dev/null +++ b/drivers/watchdog/mpc8xxx_wdt.c @@ -0,0 +1,332 @@ +/* + * mpc8xxx_wdt.c - MPC8xx/MPC83xx/MPC86xx watchdog userspace interface + * + * Authors: Dave Updegraff <dave@cray.org> + * Kumar Gala <galak@kernel.crashing.org> + * Attribution: from 83xx_wst: Florian Schirmer <jolt@tuxbox.org> + * ..and from sc520_wdt + * Copyright (c) 2008 MontaVista Software, Inc. + * Anton Vorontsov <avorontsov@ru.mvista.com> + * + * Note: it appears that you can only actually ENABLE or DISABLE the thing + * once after POR. Once enabled, you cannot disable, and vice versa. + * + * 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. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/timer.h> +#include <linux/miscdevice.h> +#include <linux/of_platform.h> +#include <linux/module.h> +#include <linux/watchdog.h> +#include <linux/io.h> +#include <linux/uaccess.h> +#include <sysdev/fsl_soc.h> + +struct mpc8xxx_wdt { + __be32 res0; + __be32 swcrr; /* System watchdog control register */ +#define SWCRR_SWTC 0xFFFF0000 /* Software Watchdog Time Count. */ +#define SWCRR_SWEN 0x00000004 /* Watchdog Enable bit. */ +#define SWCRR_SWRI 0x00000002 /* Software Watchdog Reset/Interrupt Select bit.*/ +#define SWCRR_SWPR 0x00000001 /* Software Watchdog Counter Prescale bit. */ + __be32 swcnr; /* System watchdog count register */ + u8 res1[2]; + __be16 swsrr; /* System watchdog service register */ + u8 res2[0xF0]; +}; + +struct mpc8xxx_wdt_type { + int prescaler; + bool hw_enabled; +}; + +static struct mpc8xxx_wdt __iomem *wd_base; +static int mpc8xxx_wdt_init_late(void); + +static u16 timeout = 0xffff; +module_param(timeout, ushort, 0); +MODULE_PARM_DESC(timeout, + "Watchdog timeout in ticks. (0<timeout<65536, default=65535)"); + +static bool reset = 1; +module_param(reset, bool, 0); +MODULE_PARM_DESC(reset, + "Watchdog Interrupt/Reset Mode. 0 = interrupt, 1 = reset"); + +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) ")"); + +/* + * We always prescale, but if someone really doesn't want to they can set this + * to 0 + */ +static int prescale = 1; +static unsigned int timeout_sec; + +static unsigned long wdt_is_open; +static DEFINE_SPINLOCK(wdt_spinlock); + +static void mpc8xxx_wdt_keepalive(void) +{ + /* Ping the WDT */ + spin_lock(&wdt_spinlock); + out_be16(&wd_base->swsrr, 0x556c); + out_be16(&wd_base->swsrr, 0xaa39); + spin_unlock(&wdt_spinlock); +} + +static void mpc8xxx_wdt_timer_ping(unsigned long arg); +static DEFINE_TIMER(wdt_timer, mpc8xxx_wdt_timer_ping, 0, 0); + +static void mpc8xxx_wdt_timer_ping(unsigned long arg) +{ + mpc8xxx_wdt_keepalive(); + /* We're pinging it twice faster than needed, just to be sure. */ + mod_timer(&wdt_timer, jiffies + HZ * timeout_sec / 2); +} + +static void mpc8xxx_wdt_pr_warn(const char *msg) +{ + pr_crit("%s, expect the %s soon!\n", msg, + reset ? "reset" : "machine check exception"); +} + +static ssize_t mpc8xxx_wdt_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + if (count) + mpc8xxx_wdt_keepalive(); + return count; +} + +static int mpc8xxx_wdt_open(struct inode *inode, struct file *file) +{ + u32 tmp = SWCRR_SWEN; + if (test_and_set_bit(0, &wdt_is_open)) + return -EBUSY; + + /* Once we start the watchdog we can't stop it */ + if (nowayout) + __module_get(THIS_MODULE); + + /* Good, fire up the show */ + if (prescale) + tmp |= SWCRR_SWPR; + if (reset) + tmp |= SWCRR_SWRI; + + tmp |= timeout << 16; + + out_be32(&wd_base->swcrr, tmp); + + del_timer_sync(&wdt_timer); + + return nonseekable_open(inode, file); +} + +static int mpc8xxx_wdt_release(struct inode *inode, struct file *file) +{ + if (!nowayout) + mpc8xxx_wdt_timer_ping(0); + else + mpc8xxx_wdt_pr_warn("watchdog closed"); + clear_bit(0, &wdt_is_open); + return 0; +} + +static long mpc8xxx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + static const struct watchdog_info ident = { + .options = WDIOF_KEEPALIVEPING, + .firmware_version = 1, + .identity = "MPC8xxx", + }; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + case WDIOC_KEEPALIVE: + mpc8xxx_wdt_keepalive(); + return 0; + case WDIOC_GETTIMEOUT: + return put_user(timeout_sec, p); + default: + return -ENOTTY; + } +} + +static const struct file_operations mpc8xxx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = mpc8xxx_wdt_write, + .unlocked_ioctl = mpc8xxx_wdt_ioctl, + .open = mpc8xxx_wdt_open, + .release = mpc8xxx_wdt_release, +}; + +static struct miscdevice mpc8xxx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &mpc8xxx_wdt_fops, +}; + +static const struct of_device_id mpc8xxx_wdt_match[]; +static int __devinit mpc8xxx_wdt_probe(struct platform_device *ofdev) +{ + int ret; + const struct of_device_id *match; + struct device_node *np = ofdev->dev.of_node; + struct mpc8xxx_wdt_type *wdt_type; + u32 freq = fsl_get_sys_freq(); + bool enabled; + + match = of_match_device(mpc8xxx_wdt_match, &ofdev->dev); + if (!match) + return -EINVAL; + wdt_type = match->data; + + if (!freq || freq == -1) + return -EINVAL; + + wd_base = of_iomap(np, 0); + if (!wd_base) + return -ENOMEM; + + enabled = in_be32(&wd_base->swcrr) & SWCRR_SWEN; + if (!enabled && wdt_type->hw_enabled) { + pr_info("could not be enabled in software\n"); + ret = -ENOSYS; + goto err_unmap; + } + + /* Calculate the timeout in seconds */ + if (prescale) + timeout_sec = (timeout * wdt_type->prescaler) / freq; + else + timeout_sec = timeout / freq; + +#ifdef MODULE + ret = mpc8xxx_wdt_init_late(); + if (ret) + goto err_unmap; +#endif + + pr_info("WDT driver for MPC8xxx initialized. mode:%s timeout=%d (%d seconds)\n", + reset ? "reset" : "interrupt", timeout, timeout_sec); + + /* + * If the watchdog was previously enabled or we're running on + * MPC8xxx, we should ping the wdt from the kernel until the + * userspace handles it. + */ + if (enabled) + mpc8xxx_wdt_timer_ping(0); + return 0; +err_unmap: + iounmap(wd_base); + wd_base = NULL; + return ret; +} + +static int __devexit mpc8xxx_wdt_remove(struct platform_device *ofdev) +{ + mpc8xxx_wdt_pr_warn("watchdog removed"); + del_timer_sync(&wdt_timer); + misc_deregister(&mpc8xxx_wdt_miscdev); + iounmap(wd_base); + + return 0; +} + +static const struct of_device_id mpc8xxx_wdt_match[] = { + { + .compatible = "mpc83xx_wdt", + .data = &(struct mpc8xxx_wdt_type) { + .prescaler = 0x10000, + }, + }, + { + .compatible = "fsl,mpc8610-wdt", + .data = &(struct mpc8xxx_wdt_type) { + .prescaler = 0x10000, + .hw_enabled = true, + }, + }, + { + .compatible = "fsl,mpc823-wdt", + .data = &(struct mpc8xxx_wdt_type) { + .prescaler = 0x800, + }, + }, + {}, +}; +MODULE_DEVICE_TABLE(of, mpc8xxx_wdt_match); + +static struct platform_driver mpc8xxx_wdt_driver = { + .probe = mpc8xxx_wdt_probe, + .remove = __devexit_p(mpc8xxx_wdt_remove), + .driver = { + .name = "mpc8xxx_wdt", + .owner = THIS_MODULE, + .of_match_table = mpc8xxx_wdt_match, + }, +}; + +/* + * We do wdt initialization in two steps: arch_initcall probes the wdt + * very early to start pinging the watchdog (misc devices are not yet + * available), and later module_init() just registers the misc device. + */ +static int mpc8xxx_wdt_init_late(void) +{ + int ret; + + if (!wd_base) + return -ENODEV; + + ret = misc_register(&mpc8xxx_wdt_miscdev); + if (ret) { + pr_err("cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + return ret; + } + return 0; +} +#ifndef MODULE +module_init(mpc8xxx_wdt_init_late); +#endif + +static int __init mpc8xxx_wdt_init(void) +{ + return platform_driver_register(&mpc8xxx_wdt_driver); +} +arch_initcall(mpc8xxx_wdt_init); + +static void __exit mpc8xxx_wdt_exit(void) +{ + platform_driver_unregister(&mpc8xxx_wdt_driver); +} +module_exit(mpc8xxx_wdt_exit); + +MODULE_AUTHOR("Dave Updegraff, Kumar Gala"); +MODULE_DESCRIPTION("Driver for watchdog timer in MPC8xx/MPC83xx/MPC86xx " + "uProcessors"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |