diff options
Diffstat (limited to 'drivers/watchdog/booke_wdt.c')
| -rw-r--r-- | drivers/watchdog/booke_wdt.c | 283 |
1 files changed, 180 insertions, 103 deletions
diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c index 770824458d4..08a785398ea 100644 --- a/drivers/watchdog/booke_wdt.c +++ b/drivers/watchdog/booke_wdt.c @@ -4,7 +4,7 @@ * Author: Matthew McClintock * Maintainer: Kumar Gala <galak@kernel.crashing.org> * - * Copyright 2005, 2008 Freescale Semiconductor Inc. + * Copyright 2005, 2008, 2010-2011 Freescale Semiconductor Inc. * * 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 @@ -12,16 +12,15 @@ * option) any later version. */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + #include <linux/module.h> -#include <linux/fs.h> #include <linux/smp.h> -#include <linux/miscdevice.h> -#include <linux/notifier.h> #include <linux/watchdog.h> #include <asm/reg_booke.h> -#include <asm/uaccess.h> -#include <asm/system.h> +#include <asm/time.h> +#include <asm/div64.h> /* If the kernel parameter wdt=1, the watchdog will be enabled at boot. * Also, the wdt_period sets the watchdog timer period timeout. @@ -31,156 +30,234 @@ * occur, and the final time the board will reset. */ -#ifdef CONFIG_FSL_BOOKE -#define WDT_PERIOD_DEFAULT 63 /* Ex. wdt_period=28 bus=333Mhz , reset=~40sec */ -#else -#define WDT_PERIOD_DEFAULT 3 /* Refer to the PPC40x and PPC4xx manuals */ -#endif /* for timing information */ - u32 booke_wdt_enabled; -u32 booke_wdt_period = WDT_PERIOD_DEFAULT; +u32 booke_wdt_period = CONFIG_BOOKE_WDT_DEFAULT_TIMEOUT; -#ifdef CONFIG_FSL_BOOKE -#define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15)) +#ifdef CONFIG_PPC_FSL_BOOK3E +#define WDTP(x) ((((x)&0x3)<<30)|(((x)&0x3c)<<15)) +#define WDTP_MASK (WDTP(0x3f)) #else #define WDTP(x) (TCR_WP(x)) +#define WDTP_MASK (TCR_WP_MASK) #endif -static DEFINE_SPINLOCK(booke_wdt_lock); +/* Checks wdt=x and wdt_period=xx command-line option */ +notrace int __init early_parse_wdt(char *p) +{ + if (p && strncmp(p, "0", 1) != 0) + booke_wdt_enabled = 1; + + return 0; +} +early_param("wdt", early_parse_wdt); + +int __init early_parse_wdt_period(char *p) +{ + unsigned long ret; + if (p) { + if (!kstrtol(p, 0, &ret)) + booke_wdt_period = ret; + } + + return 0; +} +early_param("wdt_period", early_parse_wdt_period); + +#ifdef CONFIG_PPC_FSL_BOOK3E + +/* For the specified period, determine the number of seconds + * corresponding to the reset time. There will be a watchdog + * exception at approximately 3/5 of this time. + * + * The formula to calculate this is given by: + * 2.5 * (2^(63-period+1)) / timebase_freq + * + * In order to simplify things, we assume that period is + * at least 1. This will still result in a very long timeout. + */ +static unsigned long long period_to_sec(unsigned int period) +{ + unsigned long long tmp = 1ULL << (64 - period); + unsigned long tmp2 = ppc_tb_freq; + + /* tmp may be a very large number and we don't want to overflow, + * so divide the timebase freq instead of multiplying tmp + */ + tmp2 = tmp2 / 5 * 2; + + do_div(tmp, tmp2); + return tmp; +} + +/* + * This procedure will find the highest period which will give a timeout + * greater than the one required. e.g. for a bus speed of 66666666 and + * and a parameter of 2 secs, then this procedure will return a value of 38. + */ +static unsigned int sec_to_period(unsigned int secs) +{ + unsigned int period; + for (period = 63; period > 0; period--) { + if (period_to_sec(period) >= secs) + return period; + } + return 0; +} + +#define MAX_WDT_TIMEOUT period_to_sec(1) + +#else /* CONFIG_PPC_FSL_BOOK3E */ + +static unsigned long long period_to_sec(unsigned int period) +{ + return period; +} + +static unsigned int sec_to_period(unsigned int secs) +{ + return secs; +} + +#define MAX_WDT_TIMEOUT 3 /* from Kconfig */ + +#endif /* !CONFIG_PPC_FSL_BOOK3E */ + +static void __booke_wdt_set(void *data) +{ + u32 val; + struct watchdog_device *wdog = data; + + val = mfspr(SPRN_TCR); + val &= ~WDTP_MASK; + val |= WDTP(sec_to_period(wdog->timeout)); + + mtspr(SPRN_TCR, val); +} + +static void booke_wdt_set(void *data) +{ + on_each_cpu(__booke_wdt_set, data, 0); +} static void __booke_wdt_ping(void *data) { mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); } -static void booke_wdt_ping(void) +static int booke_wdt_ping(struct watchdog_device *wdog) { on_each_cpu(__booke_wdt_ping, NULL, 0); + + return 0; } static void __booke_wdt_enable(void *data) { u32 val; + struct watchdog_device *wdog = data; /* clear status before enabling watchdog */ __booke_wdt_ping(NULL); val = mfspr(SPRN_TCR); - val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(booke_wdt_period)); + val &= ~WDTP_MASK; + val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(sec_to_period(wdog->timeout))); mtspr(SPRN_TCR, val); } -static ssize_t booke_wdt_write(struct file *file, const char __user *buf, - size_t count, loff_t *ppos) +/** + * booke_wdt_disable - disable the watchdog on the given CPU + * + * This function is called on each CPU. It disables the watchdog on that CPU. + * + * TCR[WRC] cannot be changed once it has been set to non-zero, but we can + * effectively disable the watchdog by setting its period to the maximum value. + */ +static void __booke_wdt_disable(void *data) { - booke_wdt_ping(); - return count; + u32 val; + + val = mfspr(SPRN_TCR); + val &= ~(TCR_WIE | WDTP_MASK); + mtspr(SPRN_TCR, val); + + /* clear status to make sure nothing is pending */ + __booke_wdt_ping(NULL); + } -static struct watchdog_info ident = { - .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, - .identity = "PowerPC Book-E Watchdog", -}; +static int booke_wdt_start(struct watchdog_device *wdog) +{ + on_each_cpu(__booke_wdt_enable, wdog, 0); + pr_debug("watchdog enabled (timeout = %u sec)\n", wdog->timeout); -static int booke_wdt_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) -{ - u32 tmp = 0; - u32 __user *p = (u32 __user *)arg; - - switch (cmd) { - case WDIOC_GETSUPPORT: - if (copy_to_user((struct watchdog_info __user *)arg, &ident, - sizeof(struct watchdog_info))) - return -EFAULT; - case WDIOC_GETSTATUS: - return put_user(ident.options, p); - case WDIOC_GETBOOTSTATUS: - /* XXX: something is clearing TSR */ - tmp = mfspr(SPRN_TSR) & TSR_WRS(3); - /* returns 1 if last reset was caused by the WDT */ - return (tmp ? 1 : 0); - case WDIOC_KEEPALIVE: - booke_wdt_ping(); - return 0; - case WDIOC_SETTIMEOUT: - if (get_user(booke_wdt_period, p)) - return -EFAULT; - mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(booke_wdt_period)); - return 0; - case WDIOC_GETTIMEOUT: - return put_user(booke_wdt_period, p); - case WDIOC_SETOPTIONS: - if (get_user(tmp, p)) - return -EINVAL; - if (tmp == WDIOS_ENABLECARD) { - booke_wdt_ping(); - break; - } else - return -EINVAL; - return 0; - default: - return -ENOTTY; - } + return 0; +} + +static int booke_wdt_stop(struct watchdog_device *wdog) +{ + on_each_cpu(__booke_wdt_disable, NULL, 0); + pr_debug("watchdog disabled\n"); return 0; } -static int booke_wdt_open(struct inode *inode, struct file *file) +static int booke_wdt_set_timeout(struct watchdog_device *wdt_dev, + unsigned int timeout) { - spin_lock(&booke_wdt_lock); - if (booke_wdt_enabled == 0) { - booke_wdt_enabled = 1; - on_each_cpu(__booke_wdt_enable, NULL, 0); - printk(KERN_INFO "PowerPC Book-E Watchdog Timer Enabled " - "(wdt_period=%d)\n", booke_wdt_period); - } - spin_unlock(&booke_wdt_lock); + if (timeout > MAX_WDT_TIMEOUT) + return -EINVAL; + wdt_dev->timeout = timeout; + booke_wdt_set(wdt_dev); - return nonseekable_open(inode, file); + return 0; } -static const struct file_operations booke_wdt_fops = { +static struct watchdog_info booke_wdt_info = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .identity = "PowerPC Book-E Watchdog", +}; + +static struct watchdog_ops booke_wdt_ops = { .owner = THIS_MODULE, - .llseek = no_llseek, - .write = booke_wdt_write, - .ioctl = booke_wdt_ioctl, - .open = booke_wdt_open, + .start = booke_wdt_start, + .stop = booke_wdt_stop, + .ping = booke_wdt_ping, + .set_timeout = booke_wdt_set_timeout, }; -static struct miscdevice booke_wdt_miscdev = { - .minor = WATCHDOG_MINOR, - .name = "watchdog", - .fops = &booke_wdt_fops, +static struct watchdog_device booke_wdt_dev = { + .info = &booke_wdt_info, + .ops = &booke_wdt_ops, + .min_timeout = 1, + .max_timeout = 0xFFFF }; static void __exit booke_wdt_exit(void) { - misc_deregister(&booke_wdt_miscdev); + watchdog_unregister_device(&booke_wdt_dev); } static int __init booke_wdt_init(void) { int ret = 0; + bool nowayout = WATCHDOG_NOWAYOUT; - printk(KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n"); - ident.firmware_version = cur_cpu_spec->pvr_value; + pr_info("powerpc book-e watchdog driver loaded\n"); + booke_wdt_info.firmware_version = cur_cpu_spec->pvr_value; + booke_wdt_set_timeout(&booke_wdt_dev, + period_to_sec(booke_wdt_period)); + watchdog_set_nowayout(&booke_wdt_dev, nowayout); + if (booke_wdt_enabled) + booke_wdt_start(&booke_wdt_dev); - ret = misc_register(&booke_wdt_miscdev); - if (ret) { - printk(KERN_CRIT "Cannot register miscdev on minor=%d: %d\n", - WATCHDOG_MINOR, ret); - return ret; - } - - spin_lock(&booke_wdt_lock); - if (booke_wdt_enabled == 1) { - printk(KERN_INFO "PowerPC Book-E Watchdog Timer Enabled " - "(wdt_period=%d)\n", booke_wdt_period); - on_each_cpu(__booke_wdt_enable, NULL, 0); - } - spin_unlock(&booke_wdt_lock); + ret = watchdog_register_device(&booke_wdt_dev); return ret; } -device_initcall(booke_wdt_init); + +module_init(booke_wdt_init); +module_exit(booke_wdt_exit); + +MODULE_DESCRIPTION("PowerPC Book-E watchdog driver"); +MODULE_LICENSE("GPL"); |