/* * 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/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 DEFINE_SPINLOCK(txx9_lock); static void txx9wdt_ping(void) { spin_lock(&txx9_lock); __raw_writel(TXx9_TMWTMR_TWIE | TXx9_TMWTMR_TWC, &txx9wdt_reg->wtmr); spin_unlock(&txx9_lock); } static void txx9wdt_start(void) { spin_lock(&txx9_lock); __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); spin_unlock(&txx9_lock); } static void txx9wdt_stop(void) { spin_lock(&txx9_lock); __raw_writel(TXx9_TMWTMR_WDIS, &txx9wdt_reg->wtmr); __raw_writel(__raw_readl(&txx9wdt_reg->tcr) & ~TXx9_TMTCR_TCE, &txx9wdt_reg->tcr); spin_unlock(&txx9_lock); } 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 long txx9wdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { void __user *argp = (void __user *)arg; int __user *p = argp; int new_timeout; static const struct watchdog_info ident = { .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, .firmware_version = 0, .identity = "Hardware Watchdog for TXx9", }; 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: 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); default: return -ENOTTY; } } static const struct file_operations txx9wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = txx9wdt_write, .unlocked_ioctl = txx9wdt_ioctl, .open = txx9wdt_open, .release = txx9wdt_release, }; static struct miscdevice txx9wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &txx9wdt_fops, }; 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, resource_size(res), "txx9wdt")) goto exit_busy; txx9wdt_reg = devm_ioremap(&dev->dev, res->start, resource_size(res)); if (!txx9wdt_reg) goto exit_busy; ret = misc_register(&txx9wdt_miscdev); if (ret) { 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); clk_disable(txx9_imclk); clk_put(txx9_imclk); return 0; } static void txx9wdt_shutdown(struct platform_device *dev) { txx9wdt_stop(); } static struct platform_driver txx9wdt_driver = { .remove = __exit_p(txx9wdt_remove), .shutdown = txx9wdt_shutdown, .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); MODULE_ALIAS("platform:txx9wdt");