/* linux/drivers/char/watchdog/s3c2410_wdt.c * * Copyright (c) 2004 Simtec Electronics * Ben Dooks <ben@simtec.co.uk> * * S3C2410 Watchdog Timer Support * * Based on, softdog.c by Alan Cox, * (c) Copyright 1996 Alan Cox <alan@redhat.com> * * 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. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * * Changelog: * 05-Oct-2004 BJD Added semaphore init to stop crashes on open * Fixed tmr_count / wdt_count confusion * Added configurable debug * * 11-Jan-2005 BJD Fixed divide-by-2 in timeout code * * 25-Jan-2005 DA Added suspend/resume support * Replaced reboot notifier with .shutdown method * * 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA */ #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/types.h> #include <linux/timer.h> #include <linux/miscdevice.h> #include <linux/watchdog.h> #include <linux/fs.h> #include <linux/init.h> #include <linux/platform_device.h> #include <linux/interrupt.h> #include <linux/clk.h> #include <asm/uaccess.h> #include <asm/io.h> #include <asm/arch/map.h> #undef S3C24XX_VA_WATCHDOG #define S3C24XX_VA_WATCHDOG (0) #include <asm/arch/regs-watchdog.h> #define PFX "s3c2410-wdt: " #define CONFIG_S3C2410_WATCHDOG_ATBOOT (0) #define CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME (15) static int nowayout = WATCHDOG_NOWAYOUT; static int tmr_margin = CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME; static int tmr_atboot = CONFIG_S3C2410_WATCHDOG_ATBOOT; static int soft_noboot = 0; static int debug = 0; module_param(tmr_margin, int, 0); module_param(tmr_atboot, int, 0); module_param(nowayout, int, 0); module_param(soft_noboot, int, 0); module_param(debug, int, 0); MODULE_PARM_DESC(tmr_margin, "Watchdog tmr_margin in seconds. default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME) ")"); MODULE_PARM_DESC(tmr_atboot, "Watchdog is started at boot time if set to 1, default=" __MODULE_STRING(CONFIG_S3C2410_WATCHDOG_ATBOOT)); MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); MODULE_PARM_DESC(soft_noboot, "Watchdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)"); MODULE_PARM_DESC(debug, "Watchdog debug, set to >1 for debug, (default 0)"); typedef enum close_state { CLOSE_STATE_NOT, CLOSE_STATE_ALLOW=0x4021 } close_state_t; static DECLARE_MUTEX(open_lock); static struct resource *wdt_mem; static struct resource *wdt_irq; static struct clk *wdt_clock; static void __iomem *wdt_base; static unsigned int wdt_count; static close_state_t allow_close; /* watchdog control routines */ #define DBG(msg...) do { \ if (debug) \ printk(KERN_INFO msg); \ } while(0) /* functions */ static int s3c2410wdt_keepalive(void) { writel(wdt_count, wdt_base + S3C2410_WTCNT); return 0; } static int s3c2410wdt_stop(void) { unsigned long wtcon; wtcon = readl(wdt_base + S3C2410_WTCON); wtcon &= ~(S3C2410_WTCON_ENABLE | S3C2410_WTCON_RSTEN); writel(wtcon, wdt_base + S3C2410_WTCON); return 0; } static int s3c2410wdt_start(void) { unsigned long wtcon; s3c2410wdt_stop(); wtcon = readl(wdt_base + S3C2410_WTCON); wtcon |= S3C2410_WTCON_ENABLE | S3C2410_WTCON_DIV128; if (soft_noboot) { wtcon |= S3C2410_WTCON_INTEN; wtcon &= ~S3C2410_WTCON_RSTEN; } else { wtcon &= ~S3C2410_WTCON_INTEN; wtcon |= S3C2410_WTCON_RSTEN; } DBG("%s: wdt_count=0x%08x, wtcon=%08lx\n", __FUNCTION__, wdt_count, wtcon); writel(wdt_count, wdt_base + S3C2410_WTDAT); writel(wdt_count, wdt_base + S3C2410_WTCNT); writel(wtcon, wdt_base + S3C2410_WTCON); return 0; } static int s3c2410wdt_set_heartbeat(int timeout) { unsigned int freq = clk_get_rate(wdt_clock); unsigned int count; unsigned int divisor = 1; unsigned long wtcon; if (timeout < 1) return -EINVAL; freq /= 128; count = timeout * freq; DBG("%s: count=%d, timeout=%d, freq=%d\n", __FUNCTION__, count, timeout, freq); /* if the count is bigger than the watchdog register, then work out what we need to do (and if) we can actually make this value */ if (count >= 0x10000) { for (divisor = 1; divisor <= 0x100; divisor++) { if ((count / divisor) < 0x10000) break; } if ((count / divisor) >= 0x10000) { printk(KERN_ERR PFX "timeout %d too big\n", timeout); return -EINVAL; } } tmr_margin = timeout; DBG("%s: timeout=%d, divisor=%d, count=%d (%08x)\n", __FUNCTION__, timeout, divisor, count, count/divisor); count /= divisor; wdt_count = count; /* update the pre-scaler */ wtcon = readl(wdt_base + S3C2410_WTCON); wtcon &= ~S3C2410_WTCON_PRESCALE_MASK; wtcon |= S3C2410_WTCON_PRESCALE(divisor-1); writel(count, wdt_base + S3C2410_WTDAT); writel(wtcon, wdt_base + S3C2410_WTCON); return 0; } /* * /dev/watchdog handling */ static int s3c2410wdt_open(struct inode *inode, struct file *file) { if(down_trylock(&open_lock)) return -EBUSY; if (nowayout) __module_get(THIS_MODULE); allow_close = CLOSE_STATE_NOT; /* start the timer */ s3c2410wdt_start(); return nonseekable_open(inode, file); } static int s3c2410wdt_release(struct inode *inode, struct file *file) { /* * Shut off the timer. * Lock it in if it's a module and we set nowayout */ if (allow_close == CLOSE_STATE_ALLOW) { s3c2410wdt_stop(); } else { printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); s3c2410wdt_keepalive(); } allow_close = CLOSE_STATE_NOT; up(&open_lock); return 0; } static ssize_t s3c2410wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* * Refresh the timer. */ if(len) { if (!nowayout) { size_t i; /* In case it was set long ago */ allow_close = CLOSE_STATE_NOT; for (i = 0; i != len; i++) { char c; if (get_user(c, data + i)) return -EFAULT; if (c == 'V') allow_close = CLOSE_STATE_ALLOW; } } s3c2410wdt_keepalive(); } return len; } #define OPTIONS WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE static struct watchdog_info s3c2410_wdt_ident = { .options = OPTIONS, .firmware_version = 0, .identity = "S3C2410 Watchdog", }; static int s3c2410wdt_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_margin; switch (cmd) { default: return -ENOTTY; case WDIOC_GETSUPPORT: return copy_to_user(argp, &s3c2410_wdt_ident, sizeof(s3c2410_wdt_ident)) ? -EFAULT : 0; case WDIOC_GETSTATUS: case WDIOC_GETBOOTSTATUS: return put_user(0, p); case WDIOC_KEEPALIVE: s3c2410wdt_keepalive(); return 0; case WDIOC_SETTIMEOUT: if (get_user(new_margin, p)) return -EFAULT; if (s3c2410wdt_set_heartbeat(new_margin)) return -EINVAL; s3c2410wdt_keepalive(); return put_user(tmr_margin, p); case WDIOC_GETTIMEOUT: return put_user(tmr_margin, p); } } /* kernel interface */ static const struct file_operations s3c2410wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .write = s3c2410wdt_write, .ioctl = s3c2410wdt_ioctl, .open = s3c2410wdt_open, .release = s3c2410wdt_release, }; static struct miscdevice s3c2410wdt_miscdev = { .minor = WATCHDOG_MINOR, .name = "watchdog", .fops = &s3c2410wdt_fops, }; /* interrupt handler code */ static irqreturn_t s3c2410wdt_irq(int irqno, void *param) { printk(KERN_INFO PFX "Watchdog timer expired!\n"); s3c2410wdt_keepalive(); return IRQ_HANDLED; } /* device interface */ static int s3c2410wdt_probe(struct platform_device *pdev) { struct resource *res; int started = 0; int ret; int size; DBG("%s: probe=%p\n", __FUNCTION__, pdev); /* get the memory region for the watchdog timer */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { printk(KERN_INFO PFX "failed to get memory region resouce\n"); return -ENOENT; } size = (res->end-res->start)+1; wdt_mem = request_mem_region(res->start, size, pdev->name); if (wdt_mem == NULL) { printk(KERN_INFO PFX "failed to get memory region\n"); ret = -ENOENT; goto err_req; } wdt_base = ioremap(res->start, size); if (wdt_base == 0) { printk(KERN_INFO PFX "failed to ioremap() region\n"); ret = -EINVAL; goto err_req; } DBG("probe: mapped wdt_base=%p\n", wdt_base); res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); if (res == NULL) { printk(KERN_INFO PFX "failed to get irq resource\n"); ret = -ENOENT; goto err_map; } ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, pdev); if (ret != 0) { printk(KERN_INFO PFX "failed to install irq (%d)\n", ret); goto err_map; } wdt_clock = clk_get(&pdev->dev, "watchdog"); if (IS_ERR(wdt_clock)) { printk(KERN_INFO PFX "failed to find watchdog clock source\n"); ret = PTR_ERR(wdt_clock); goto err_irq; } clk_enable(wdt_clock); /* see if we can actually set the requested timer margin, and if * not, try the default value */ if (s3c2410wdt_set_heartbeat(tmr_margin)) { started = s3c2410wdt_set_heartbeat(CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); if (started == 0) { printk(KERN_INFO PFX "tmr_margin value out of range, default %d used\n", CONFIG_S3C2410_WATCHDOG_DEFAULT_TIME); } else { printk(KERN_INFO PFX "default timer value is out of range, cannot start\n"); } } ret = misc_register(&s3c2410wdt_miscdev); if (ret) { printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n", WATCHDOG_MINOR, ret); goto err_clk; } if (tmr_atboot && started == 0) { printk(KERN_INFO PFX "Starting Watchdog Timer\n"); s3c2410wdt_start(); } else if (!tmr_atboot) { /* if we're not enabling the watchdog, then ensure it is * disabled if it has been left running from the bootloader * or other source */ s3c2410wdt_stop(); } return 0; err_clk: clk_disable(wdt_clock); clk_put(wdt_clock); err_irq: free_irq(wdt_irq->start, pdev); err_map: iounmap(wdt_base); err_req: release_resource(wdt_mem); kfree(wdt_mem); return ret; } static int s3c2410wdt_remove(struct platform_device *dev) { release_resource(wdt_mem); kfree(wdt_mem); wdt_mem = NULL; free_irq(wdt_irq->start, dev); wdt_irq = NULL; clk_disable(wdt_clock); clk_put(wdt_clock); wdt_clock = NULL; iounmap(wdt_base); misc_deregister(&s3c2410wdt_miscdev); return 0; } static void s3c2410wdt_shutdown(struct platform_device *dev) { s3c2410wdt_stop(); } #ifdef CONFIG_PM static unsigned long wtcon_save; static unsigned long wtdat_save; static int s3c2410wdt_suspend(struct platform_device *dev, pm_message_t state) { /* Save watchdog state, and turn it off. */ wtcon_save = readl(wdt_base + S3C2410_WTCON); wtdat_save = readl(wdt_base + S3C2410_WTDAT); /* Note that WTCNT doesn't need to be saved. */ s3c2410wdt_stop(); return 0; } static int s3c2410wdt_resume(struct platform_device *dev) { /* Restore watchdog state. */ writel(wtdat_save, wdt_base + S3C2410_WTDAT); writel(wtdat_save, wdt_base + S3C2410_WTCNT); /* Reset count */ writel(wtcon_save, wdt_base + S3C2410_WTCON); printk(KERN_INFO PFX "watchdog %sabled\n", (wtcon_save & S3C2410_WTCON_ENABLE) ? "en" : "dis"); return 0; } #else #define s3c2410wdt_suspend NULL #define s3c2410wdt_resume NULL #endif /* CONFIG_PM */ static struct platform_driver s3c2410wdt_driver = { .probe = s3c2410wdt_probe, .remove = s3c2410wdt_remove, .shutdown = s3c2410wdt_shutdown, .suspend = s3c2410wdt_suspend, .resume = s3c2410wdt_resume, .driver = { .owner = THIS_MODULE, .name = "s3c2410-wdt", }, }; static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n"; static int __init watchdog_init(void) { printk(banner); return platform_driver_register(&s3c2410wdt_driver); } static void __exit watchdog_exit(void) { platform_driver_unregister(&s3c2410wdt_driver); } module_init(watchdog_init); module_exit(watchdog_exit); MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>, " "Dimitry Andric <dimitry.andric@tomtom.com>"); MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);