diff options
Diffstat (limited to 'drivers/watchdog/txx9wdt.c')
| -rw-r--r-- | drivers/watchdog/txx9wdt.c | 276 |
1 files changed, 276 insertions, 0 deletions
diff --git a/drivers/watchdog/txx9wdt.c b/drivers/watchdog/txx9wdt.c new file mode 100644 index 000000000000..328b3c7211ef --- /dev/null +++ b/drivers/watchdog/txx9wdt.c @@ -0,0 +1,276 @@ +/* + * txx9wdt: A Hardware Watchdog Driver for TXx9 SoCs + * + * Copyright (C) 2007 Atsushi Nemoto <anemo@mba.ocn.ne.jp> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/types.h> +#include <linux/miscdevice.h> +#include <linux/watchdog.h> +#include <linux/fs.h> +#include <linux/reboot.h> +#include <linux/init.h> +#include <linux/uaccess.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <asm/txx9tmr.h> + +#define TIMER_MARGIN 60 /* Default is 60 seconds */ + +static int timeout = TIMER_MARGIN; /* in seconds */ +module_param(timeout, int, 0); +MODULE_PARM_DESC(timeout, + "Watchdog timeout in seconds. " + "(0<timeout<((2^" __MODULE_STRING(TXX9_TIMER_BITS) ")/(IMCLK/256)), " + "default=" __MODULE_STRING(TIMER_MARGIN) ")"); + +static int nowayout = WATCHDOG_NOWAYOUT; +module_param(nowayout, int, 0); +MODULE_PARM_DESC(nowayout, + "Watchdog cannot be stopped once started " + "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); + +#define WD_TIMER_CCD 7 /* 1/256 */ +#define WD_TIMER_CLK (clk_get_rate(txx9_imclk) / (2 << WD_TIMER_CCD)) +#define WD_MAX_TIMEOUT ((0xffffffff >> (32 - TXX9_TIMER_BITS)) / WD_TIMER_CLK) + +static unsigned long txx9wdt_alive; +static int expect_close; +static struct txx9_tmr_reg __iomem *txx9wdt_reg; +static struct clk *txx9_imclk; + +static void txx9wdt_ping(void) +{ + __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); +} + +static void txx9wdt_start(void) +{ + __raw_writel(WD_TIMER_CLK * timeout, &txx9wdt_reg->cpra); + __raw_writel(WD_TIMER_CCD, &txx9wdt_reg->ccdr); + __raw_writel(0, &txx9wdt_reg->tisr); /* clear pending interrupt */ + __raw_writel(TXx9_TMTCR_TCE | TXx9_TMTCR_CCDE | TXx9_TMTCR_TMODE_WDOG, + &txx9wdt_reg->tcr); + __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); +} + +static void txx9wdt_stop(void) +{ + __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); + __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, + &txx9wdt_reg->tcr); +} + +static int txx9wdt_open(struct inode *inode, struct file *file) +{ + if (test_and_set_bit(0, &txx9wdt_alive)) + return -EBUSY; + + if (__raw_readl(&txx9wdt_reg->tcr) & TXx9_TMTCR_TCE) { + clear_bit(0, &txx9wdt_alive); + return -EBUSY; + } + + if (nowayout) + __module_get(THIS_MODULE); + + txx9wdt_start(); + return nonseekable_open(inode, file); +} + +static int txx9wdt_release(struct inode *inode, struct file *file) +{ + if (expect_close) + txx9wdt_stop(); + else { + printk(KERN_CRIT "txx9wdt: " + "Unexpected close, not stopping watchdog!\n"); + txx9wdt_ping(); + } + clear_bit(0, &txx9wdt_alive); + expect_close = 0; + return 0; +} + +static ssize_t txx9wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + if (len) { + if (!nowayout) { + size_t i; + + expect_close = 0; + for (i = 0; i != len; i++) { + char c; + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') + expect_close = 1; + } + } + txx9wdt_ping(); + } + return len; +} + +static int txx9wdt_ioctl(struct inode *inode, struct file *file, + unsigned int cmd, unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int new_timeout; + static struct watchdog_info ident = { + .options = WDIOF_SETTIMEOUT | + WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, + .firmware_version = 0, + .identity = "Hardware Watchdog for TXx9", + }; + + switch (cmd) { + default: + return -ENOTTY; + 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: + txx9wdt_ping(); + return 0; + case WDIOC_SETTIMEOUT: + if (get_user(new_timeout, p)) + return -EFAULT; + if (new_timeout < 1 || new_timeout > WD_MAX_TIMEOUT) + return -EINVAL; + timeout = new_timeout; + txx9wdt_stop(); + txx9wdt_start(); + /* Fall */ + case WDIOC_GETTIMEOUT: + return put_user(timeout, p); + } +} + +static int txx9wdt_notify_sys(struct notifier_block *this, unsigned long code, + void *unused) +{ + if (code == SYS_DOWN || code == SYS_HALT) + txx9wdt_stop(); + return NOTIFY_DONE; +} + +static const struct file_operations txx9wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .write = txx9wdt_write, + .ioctl = txx9wdt_ioctl, + .open = txx9wdt_open, + .release = txx9wdt_release, +}; + +static struct miscdevice txx9wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &txx9wdt_fops, +}; + +static struct notifier_block txx9wdt_notifier = { + .notifier_call = txx9wdt_notify_sys +}; + +static int __init txx9wdt_probe(struct platform_device *dev) +{ + struct resource *res; + int ret; + + txx9_imclk = clk_get(NULL, "imbus_clk"); + if (IS_ERR(txx9_imclk)) { + ret = PTR_ERR(txx9_imclk); + txx9_imclk = NULL; + goto exit; + } + ret = clk_enable(txx9_imclk); + if (ret) { + clk_put(txx9_imclk); + txx9_imclk = NULL; + goto exit; + } + + res = platform_get_resource(dev, IORESOURCE_MEM, 0); + if (!res) + goto exit_busy; + if (!devm_request_mem_region(&dev->dev, + res->start, res->end - res->start + 1, + "txx9wdt")) + goto exit_busy; + txx9wdt_reg = devm_ioremap(&dev->dev, + res->start, res->end - res->start + 1); + if (!txx9wdt_reg) + goto exit_busy; + + ret = register_reboot_notifier(&txx9wdt_notifier); + if (ret) + goto exit; + + ret = misc_register(&txx9wdt_miscdev); + if (ret) { + unregister_reboot_notifier(&txx9wdt_notifier); + goto exit; + } + + printk(KERN_INFO "Hardware Watchdog Timer for TXx9: " + "timeout=%d sec (max %ld) (nowayout= %d)\n", + timeout, WD_MAX_TIMEOUT, nowayout); + + return 0; +exit_busy: + ret = -EBUSY; +exit: + if (txx9_imclk) { + clk_disable(txx9_imclk); + clk_put(txx9_imclk); + } + return ret; +} + +static int __exit txx9wdt_remove(struct platform_device *dev) +{ + misc_deregister(&txx9wdt_miscdev); + unregister_reboot_notifier(&txx9wdt_notifier); + clk_disable(txx9_imclk); + clk_put(txx9_imclk); + return 0; +} + +static struct platform_driver txx9wdt_driver = { + .remove = __exit_p(txx9wdt_remove), + .driver = { + .name = "txx9wdt", + .owner = THIS_MODULE, + }, +}; + +static int __init watchdog_init(void) +{ + return platform_driver_probe(&txx9wdt_driver, txx9wdt_probe); +} + +static void __exit watchdog_exit(void) +{ + platform_driver_unregister(&txx9wdt_driver); +} + +module_init(watchdog_init); +module_exit(watchdog_exit); + +MODULE_DESCRIPTION("TXx9 Watchdog Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |