diff options
Diffstat (limited to 'drivers/char/watchdog/booke_wdt.c')
| -rw-r--r-- | drivers/char/watchdog/booke_wdt.c | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/drivers/char/watchdog/booke_wdt.c b/drivers/char/watchdog/booke_wdt.c new file mode 100644 index 000000000000..7281f394f682 --- /dev/null +++ b/drivers/char/watchdog/booke_wdt.c @@ -0,0 +1,191 @@ +/* + * drivers/char/watchdog/booke_wdt.c + * + * Watchdog timer for PowerPC Book-E systems + * + * Author: Matthew McClintock + * Maintainer: Kumar Gala <kumar.gala@freescale.com> + * + * Copyright 2005 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 + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + */ + +#include <linux/config.h> +#include <linux/module.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/notifier.h> +#include <linux/watchdog.h> + +#include <asm/reg_booke.h> +#include <asm/uaccess.h> + +/* If the kernel parameter wdt_enable=1, the watchdog will be enabled at boot. + * Also, the wdt_period sets the watchdog timer period timeout. + * For E500 cpus the wdt_period sets which bit changing from 0->1 will + * trigger a watchog timeout. This watchdog timeout will occur 3 times, the + * first time nothing will happen, the second time a watchdog exception will + * 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 4 /* Refer to the PPC40x and PPC4xx manuals */ +#endif /* for timing information */ + +u32 wdt_enable = 0; +u32 wdt_period = WDT_PERIOD_DEFAULT; + +#ifdef CONFIG_FSL_BOOKE +#define WDTP(x) ((((63-x)&0x3)<<30)|(((63-x)&0x3c)<<15)) +#else +#define WDTP(x) (TCR_WP(x)) +#endif + +/* + * booke_wdt_enable: + */ +static __inline__ void booke_wdt_enable(void) +{ + u32 val; + + val = mfspr(SPRN_TCR); + val |= (TCR_WIE|TCR_WRC(WRC_CHIP)|WDTP(wdt_period)); + + mtspr(SPRN_TCR, val); +} + +/* + * booke_wdt_ping: + */ +static __inline__ void booke_wdt_ping(void) +{ + mtspr(SPRN_TSR, TSR_ENW|TSR_WIS); +} + +/* + * booke_wdt_write: + */ +static ssize_t booke_wdt_write (struct file *file, const char *buf, + size_t count, loff_t *ppos) +{ + booke_wdt_ping(); + return count; +} + +static struct watchdog_info ident = { + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING, + .firmware_version = 0, + .identity = "PowerPC Book-E Watchdog", +}; + +/* + * booke_wdt_ioctl: + */ +static int booke_wdt_ioctl (struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + u32 tmp = 0; + + switch (cmd) { + case WDIOC_GETSUPPORT: + if (copy_to_user ((struct watchdog_info *) arg, &ident, + sizeof(struct watchdog_info))) + return -EFAULT; + case WDIOC_GETSTATUS: + return put_user(ident.options, (u32 *) arg); + 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(wdt_period, (u32 *) arg)) + return -EFAULT; + mtspr(SPRN_TCR, (mfspr(SPRN_TCR)&~WDTP(0))|WDTP(wdt_period)); + return 0; + case WDIOC_GETTIMEOUT: + return put_user(wdt_period, (u32 *) arg); + case WDIOC_SETOPTIONS: + if (get_user(tmp, (u32 *) arg)) + return -EINVAL; + if (tmp == WDIOS_ENABLECARD) { + booke_wdt_ping(); + break; + } else + return -EINVAL; + return 0; + default: + return -ENOIOCTLCMD; + } + + return 0; +} +/* + * booke_wdt_open: + */ +static int booke_wdt_open (struct inode *inode, struct file *file) +{ + if (wdt_enable == 0) { + wdt_enable = 1; + booke_wdt_enable(); + printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", + wdt_period); + } + + return 0; +} + +static struct file_operations booke_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = booke_wdt_write, + .ioctl = booke_wdt_ioctl, + .open = booke_wdt_open, +}; + +static struct miscdevice booke_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &booke_wdt_fops, +}; + +static void __exit booke_wdt_exit(void) +{ + misc_deregister(&booke_wdt_miscdev); +} + +/* + * booke_wdt_init: + */ +static int __init booke_wdt_init(void) +{ + int ret = 0; + + printk (KERN_INFO "PowerPC Book-E Watchdog Timer Loaded\n"); + ident.firmware_version = cpu_specs[0].pvr_value; + + ret = misc_register(&booke_wdt_miscdev); + if (ret) { + printk (KERN_CRIT "Cannot register miscdev on minor=%d (err=%d)\n", + WATCHDOG_MINOR, ret); + return ret; + } + + if (wdt_enable == 1) { + printk (KERN_INFO "PowerPC Book-E Watchdog Timer Enabled (wdt_period=%d)\n", + wdt_period); + booke_wdt_enable(); + } + + return ret; +} +device_initcall(booke_wdt_init); |