diff options
Diffstat (limited to 'drivers/watchdog/m54xx_wdt.c')
| -rw-r--r-- | drivers/watchdog/m54xx_wdt.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/watchdog/m54xx_wdt.c b/drivers/watchdog/m54xx_wdt.c new file mode 100644 index 00000000..663cad86 --- /dev/null +++ b/drivers/watchdog/m54xx_wdt.c @@ -0,0 +1,227 @@ +/* + * drivers/watchdog/m54xx_wdt.c + * + * Watchdog driver for ColdFire MCF547x & MCF548x processors + * Copyright 2010 (c) Philippe De Muyter <phdm@macqel.be> + * + * Adapted from the IXP4xx watchdog driver, which carries these notices: + * + * Author: Deepak Saxena <dsaxena@plexity.net> + * + * Copyright 2004 (c) MontaVista, Software, Inc. + * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu> + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/fs.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/init.h> +#include <linux/bitops.h> +#include <linux/ioport.h> +#include <linux/uaccess.h> + +#include <asm/coldfire.h> +#include <asm/m54xxsim.h> +#include <asm/m54xxgpt.h> + +static bool nowayout = WATCHDOG_NOWAYOUT; +static unsigned int heartbeat = 30; /* (secs) Default is 0.5 minute */ +static unsigned long wdt_status; + +#define WDT_IN_USE 0 +#define WDT_OK_TO_CLOSE 1 + +static void wdt_enable(void) +{ + unsigned int gms0; + + /* preserve GPIO usage, if any */ + gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); + if (gms0 & MCF_GPT_GMS_TMS_GPIO) + gms0 &= (MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_GPIO_MASK + | MCF_GPT_GMS_OD); + else + gms0 = MCF_GPT_GMS_TMS_GPIO | MCF_GPT_GMS_OD; + __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); + __raw_writel(MCF_GPT_GCIR_PRE(heartbeat*(MCF_BUSCLK/0xffff)) | + MCF_GPT_GCIR_CNT(0xffff), MCF_MBAR + MCF_GPT_GCIR0); + gms0 |= MCF_GPT_GMS_OCPW(0xA5) | MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE; + __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); +} + +static void wdt_disable(void) +{ + unsigned int gms0; + + /* disable watchdog */ + gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); + gms0 &= ~(MCF_GPT_GMS_WDEN | MCF_GPT_GMS_CE); + __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); +} + +static void wdt_keepalive(void) +{ + unsigned int gms0; + + gms0 = __raw_readl(MCF_MBAR + MCF_GPT_GMS0); + gms0 |= MCF_GPT_GMS_OCPW(0xA5); + __raw_writel(gms0, MCF_MBAR + MCF_GPT_GMS0); +} + +static int m54xx_wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(WDT_IN_USE, &wdt_status)) + return -EBUSY; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + wdt_enable(); + return nonseekable_open(inode, file); +} + +static ssize_t m54xx_wdt_write(struct file *file, const char *data, + size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + for (i = 0; i != len; i++) { + char c; + + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + set_bit(WDT_OK_TO_CLOSE, &wdt_status); + } + } + wdt_keepalive(); + } + return len; +} + +static const struct watchdog_info ident = { + .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING, + .identity = "Coldfire M54xx Watchdog", +}; + +static long m54xx_wdt_ioctl(struct file *file, unsigned int cmd, + unsigned long arg) +{ + int ret = -ENOTTY; + int time; + + switch (cmd) { + case WDIOC_GETSUPPORT: + ret = copy_to_user((struct watchdog_info *)arg, &ident, + sizeof(ident)) ? -EFAULT : 0; + break; + + case WDIOC_GETSTATUS: + ret = put_user(0, (int *)arg); + break; + + case WDIOC_GETBOOTSTATUS: + ret = put_user(0, (int *)arg); + break; + + case WDIOC_KEEPALIVE: + wdt_keepalive(); + ret = 0; + break; + + case WDIOC_SETTIMEOUT: + ret = get_user(time, (int *)arg); + if (ret) + break; + + if (time <= 0 || time > 30) { + ret = -EINVAL; + break; + } + + heartbeat = time; + wdt_enable(); + /* Fall through */ + + case WDIOC_GETTIMEOUT: + ret = put_user(heartbeat, (int *)arg); + break; + } + return ret; +} + +static int m54xx_wdt_release(struct inode *inode, struct file *file) +{ + if (test_bit(WDT_OK_TO_CLOSE, &wdt_status)) + wdt_disable(); + else { + pr_crit("Device closed unexpectedly - timer will not stop\n"); + wdt_keepalive(); + } + clear_bit(WDT_IN_USE, &wdt_status); + clear_bit(WDT_OK_TO_CLOSE, &wdt_status); + + return 0; +} + + +static const struct file_operations m54xx_wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = m54xx_wdt_write, + .unlocked_ioctl = m54xx_wdt_ioctl, + .open = m54xx_wdt_open, + .release = m54xx_wdt_release, +}; + +static struct miscdevice m54xx_wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &m54xx_wdt_fops, +}; + +static int __init m54xx_wdt_init(void) +{ + if (!request_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4, + "Coldfire M54xx Watchdog")) { + pr_warn("I/O region busy\n"); + return -EBUSY; + } + pr_info("driver is loaded\n"); + + return misc_register(&m54xx_wdt_miscdev); +} + +static void __exit m54xx_wdt_exit(void) +{ + misc_deregister(&m54xx_wdt_miscdev); + release_mem_region(MCF_MBAR + MCF_GPT_GCIR0, 4); +} + +module_init(m54xx_wdt_init); +module_exit(m54xx_wdt_exit); + +MODULE_AUTHOR("Philippe De Muyter <phdm@macqel.be>"); +MODULE_DESCRIPTION("Coldfire M54xx Watchdog"); + +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 30s)"); + +module_param(nowayout, bool, 0); +MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started"); + +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |