| /* 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 |
| * |
| * 10-Mar-2005 LCVR Changed S3C2410_VA to S3C24XX_VA |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/config.h> |
| #include <linux/types.h> |
| #include <linux/timer.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/fs.h> |
| #include <linux/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/device.h> |
| #include <linux/interrupt.h> |
| |
| #include <asm/uaccess.h> |
| #include <asm/io.h> |
| |
| #include <asm/arch/map.h> |
| #include <asm/hardware/clock.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); |
| } else { |
| allow_close = CLOSE_STATE_ALLOW; |
| } |
| |
| /* 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 -ENOIOCTLCMD; |
| |
| 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); |
| } |
| } |
| |
| /* |
| * Notifier for system down |
| */ |
| |
| static int s3c2410wdt_notify_sys(struct notifier_block *this, unsigned long code, |
| void *unused) |
| { |
| if(code==SYS_DOWN || code==SYS_HALT) { |
| /* Turn the WDT off */ |
| s3c2410wdt_stop(); |
| } |
| return NOTIFY_DONE; |
| } |
| |
| /* kernel interface */ |
| |
| static 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, |
| }; |
| |
| static struct notifier_block s3c2410wdt_notifier = { |
| .notifier_call = s3c2410wdt_notify_sys, |
| }; |
| |
| /* interrupt handler code */ |
| |
| static irqreturn_t s3c2410wdt_irq(int irqno, void *param, |
| struct pt_regs *regs) |
| { |
| printk(KERN_INFO PFX "Watchdog timer expired!\n"); |
| |
| s3c2410wdt_keepalive(); |
| return IRQ_HANDLED; |
| } |
| /* device interface */ |
| |
| static int s3c2410wdt_probe(struct device *dev) |
| { |
| struct platform_device *pdev = to_platform_device(dev); |
| struct resource *res; |
| int started = 0; |
| int ret; |
| int size; |
| |
| DBG("%s: probe=%p, device=%p\n", __FUNCTION__, pdev, dev); |
| |
| /* 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"); |
| return -ENOENT; |
| } |
| |
| wdt_base = ioremap(res->start, size); |
| if (wdt_base == 0) { |
| printk(KERN_INFO PFX "failed to ioremap() region\n"); |
| return -EINVAL; |
| } |
| |
| 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"); |
| return -ENOENT; |
| } |
| |
| ret = request_irq(res->start, s3c2410wdt_irq, 0, pdev->name, dev); |
| if (ret != 0) { |
| printk(KERN_INFO PFX "failed to install irq (%d)\n", ret); |
| return ret; |
| } |
| |
| wdt_clock = clk_get(dev, "watchdog"); |
| if (wdt_clock == NULL) { |
| printk(KERN_INFO PFX "failed to find watchdog clock source\n"); |
| return -ENOENT; |
| } |
| |
| clk_use(wdt_clock); |
| 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 = register_reboot_notifier(&s3c2410wdt_notifier); |
| if (ret) { |
| printk (KERN_ERR PFX "cannot register reboot notifier (%d)\n", |
| ret); |
| return ret; |
| } |
| |
| ret = misc_register(&s3c2410wdt_miscdev); |
| if (ret) { |
| printk (KERN_ERR PFX "cannot register miscdev on minor=%d (%d)\n", |
| WATCHDOG_MINOR, ret); |
| unregister_reboot_notifier(&s3c2410wdt_notifier); |
| return ret; |
| } |
| |
| if (tmr_atboot && started == 0) { |
| printk(KERN_INFO PFX "Starting Watchdog Timer\n"); |
| s3c2410wdt_start(); |
| } |
| |
| return 0; |
| } |
| |
| static int s3c2410wdt_remove(struct device *dev) |
| { |
| if (wdt_mem != NULL) { |
| release_resource(wdt_mem); |
| kfree(wdt_mem); |
| wdt_mem = NULL; |
| } |
| |
| if (wdt_irq != NULL) { |
| free_irq(wdt_irq->start, dev); |
| wdt_irq = NULL; |
| } |
| |
| if (wdt_clock != NULL) { |
| clk_disable(wdt_clock); |
| clk_unuse(wdt_clock); |
| clk_put(wdt_clock); |
| wdt_clock = NULL; |
| } |
| |
| misc_deregister(&s3c2410wdt_miscdev); |
| return 0; |
| } |
| |
| #ifdef CONFIG_PM |
| |
| static unsigned long wtcon_save; |
| static unsigned long wtdat_save; |
| |
| static int s3c2410wdt_suspend(struct device *dev, u32 state, u32 level) |
| { |
| if (level == SUSPEND_POWER_DOWN) { |
| /* 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 device *dev, u32 level) |
| { |
| if (level == RESUME_POWER_ON) { |
| /* 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 device_driver s3c2410wdt_driver = { |
| .name = "s3c2410-wdt", |
| .bus = &platform_bus_type, |
| .probe = s3c2410wdt_probe, |
| .remove = s3c2410wdt_remove, |
| .suspend = s3c2410wdt_suspend, |
| .resume = s3c2410wdt_resume, |
| }; |
| |
| |
| static char banner[] __initdata = KERN_INFO "S3C2410 Watchdog Timer, (c) 2004 Simtec Electronics\n"; |
| |
| static int __init watchdog_init(void) |
| { |
| printk(banner); |
| return driver_register(&s3c2410wdt_driver); |
| } |
| |
| static void __exit watchdog_exit(void) |
| { |
| driver_unregister(&s3c2410wdt_driver); |
| unregister_reboot_notifier(&s3c2410wdt_notifier); |
| } |
| |
| 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); |