diff options
Diffstat (limited to 'drivers/char/watchdog/s3c2410_wdt.c')
| -rw-r--r-- | drivers/char/watchdog/s3c2410_wdt.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/drivers/char/watchdog/s3c2410_wdt.c b/drivers/char/watchdog/s3c2410_wdt.c new file mode 100644 index 00000000000..1699d2c28ce --- /dev/null +++ b/drivers/char/watchdog/s3c2410_wdt.c @@ -0,0 +1,516 @@ +/* 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-2004 BJD Fixed divide-by-2 in timeout code + * + * 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) + +#ifdef CONFIG_WATCHDOG_NOWAYOUT +static int nowayout = 1; +#else +static int nowayout = 0; +#endif + +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; +} + +static struct device_driver s3c2410wdt_driver = { + .name = "s3c2410-wdt", + .bus = &platform_bus_type, + .probe = s3c2410wdt_probe, + .remove = s3c2410wdt_remove, +}; + + + +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>"); +MODULE_DESCRIPTION("S3C2410 Watchdog Device Driver"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |