diff options
Diffstat (limited to 'drivers/watchdog/nuc900_wdt.c')
| -rw-r--r-- | drivers/watchdog/nuc900_wdt.c | 353 |
1 files changed, 353 insertions, 0 deletions
diff --git a/drivers/watchdog/nuc900_wdt.c b/drivers/watchdog/nuc900_wdt.c new file mode 100644 index 000000000000..adefe3a9d510 --- /dev/null +++ b/drivers/watchdog/nuc900_wdt.c @@ -0,0 +1,353 @@ +/* + * Copyright (c) 2009 Nuvoton technology corporation. + * + * Wan ZongShun <mcuos.com@gmail.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;version 2 of the License. + * + */ + +#include <linux/bitops.h> +#include <linux/errno.h> +#include <linux/fs.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/kernel.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/platform_device.h> +#include <linux/interrupt.h> +#include <linux/types.h> +#include <linux/watchdog.h> +#include <linux/uaccess.h> + +#define REG_WTCR 0x1c +#define WTCLK (0x01 << 10) +#define WTE (0x01 << 7) /*wdt enable*/ +#define WTIS (0x03 << 4) +#define WTIF (0x01 << 3) +#define WTRF (0x01 << 2) +#define WTRE (0x01 << 1) +#define WTR (0x01 << 0) +/* + * The watchdog time interval can be calculated via following formula: + * WTIS real time interval (formula) + * 0x00 ((2^ 14 ) * ((external crystal freq) / 256))seconds + * 0x01 ((2^ 16 ) * ((external crystal freq) / 256))seconds + * 0x02 ((2^ 18 ) * ((external crystal freq) / 256))seconds + * 0x03 ((2^ 20 ) * ((external crystal freq) / 256))seconds + * + * The external crystal freq is 15Mhz in the nuc900 evaluation board. + * So 0x00 = +-0.28 seconds, 0x01 = +-1.12 seconds, 0x02 = +-4.48 seconds, + * 0x03 = +- 16.92 seconds.. + */ +#define WDT_HW_TIMEOUT 0x02 +#define WDT_TIMEOUT (HZ/2) +#define WDT_HEARTBEAT 15 + +static int heartbeat = WDT_HEARTBEAT; +module_param(heartbeat, int, 0); +MODULE_PARM_DESC(heartbeat, "Watchdog heartbeats in seconds. " + "(default = " __MODULE_STRING(WDT_HEARTBEAT) ")"); + +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) ")"); + +struct nuc900_wdt { + struct resource *res; + struct clk *wdt_clock; + struct platform_device *pdev; + void __iomem *wdt_base; + char expect_close; + struct timer_list timer; + spinlock_t wdt_lock; + unsigned long next_heartbeat; +}; + +static unsigned long nuc900wdt_busy; +struct nuc900_wdt *nuc900_wdt; + +static inline void nuc900_wdt_keepalive(void) +{ + unsigned int val; + + spin_lock(&nuc900_wdt->wdt_lock); + + val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); + val |= (WTR | WTIF); + __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); + + spin_unlock(&nuc900_wdt->wdt_lock); +} + +static inline void nuc900_wdt_start(void) +{ + unsigned int val; + + spin_lock(&nuc900_wdt->wdt_lock); + + val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); + val |= (WTRE | WTE | WTR | WTCLK | WTIF); + val &= ~WTIS; + val |= (WDT_HW_TIMEOUT << 0x04); + __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); + + spin_unlock(&nuc900_wdt->wdt_lock); + + nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; + mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); +} + +static inline void nuc900_wdt_stop(void) +{ + unsigned int val; + + del_timer(&nuc900_wdt->timer); + + spin_lock(&nuc900_wdt->wdt_lock); + + val = __raw_readl(nuc900_wdt->wdt_base + REG_WTCR); + val &= ~WTE; + __raw_writel(val, nuc900_wdt->wdt_base + REG_WTCR); + + spin_unlock(&nuc900_wdt->wdt_lock); +} + +static inline void nuc900_wdt_ping(void) +{ + nuc900_wdt->next_heartbeat = jiffies + heartbeat * HZ; +} + +static int nuc900_wdt_open(struct inode *inode, struct file *file) +{ + + if (test_and_set_bit(0, &nuc900wdt_busy)) + return -EBUSY; + + nuc900_wdt_start(); + + return nonseekable_open(inode, file); +} + +static int nuc900_wdt_close(struct inode *inode, struct file *file) +{ + if (nuc900_wdt->expect_close == 42) + nuc900_wdt_stop(); + else { + dev_crit(&nuc900_wdt->pdev->dev, + "Unexpected close, not stopping watchdog!\n"); + nuc900_wdt_ping(); + } + + nuc900_wdt->expect_close = 0; + clear_bit(0, &nuc900wdt_busy); + return 0; +} + +static const struct watchdog_info nuc900_wdt_info = { + .identity = "nuc900 watchdog", + .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | + WDIOF_MAGICCLOSE, +}; + +static long nuc900_wdt_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) +{ + void __user *argp = (void __user *)arg; + int __user *p = argp; + int new_value; + + switch (cmd) { + case WDIOC_GETSUPPORT: + return copy_to_user(argp, &nuc900_wdt_info, + sizeof(nuc900_wdt_info)) ? -EFAULT : 0; + case WDIOC_GETSTATUS: + case WDIOC_GETBOOTSTATUS: + return put_user(0, p); + + case WDIOC_KEEPALIVE: + nuc900_wdt_ping(); + return 0; + + case WDIOC_SETTIMEOUT: + if (get_user(new_value, p)) + return -EFAULT; + + heartbeat = new_value; + nuc900_wdt_ping(); + + return put_user(new_value, p); + case WDIOC_GETTIMEOUT: + return put_user(heartbeat, p); + default: + return -ENOTTY; + } +} + +static ssize_t nuc900_wdt_write(struct file *file, const char __user *data, + size_t len, loff_t *ppos) +{ + if (!len) + return 0; + + /* Scan for magic character */ + if (!nowayout) { + size_t i; + + nuc900_wdt->expect_close = 0; + + for (i = 0; i < len; i++) { + char c; + if (get_user(c, data + i)) + return -EFAULT; + if (c == 'V') { + nuc900_wdt->expect_close = 42; + break; + } + } + } + + nuc900_wdt_ping(); + return len; +} + +static void nuc900_wdt_timer_ping(unsigned long data) +{ + if (time_before(jiffies, nuc900_wdt->next_heartbeat)) { + nuc900_wdt_keepalive(); + mod_timer(&nuc900_wdt->timer, jiffies + WDT_TIMEOUT); + } else + dev_warn(&nuc900_wdt->pdev->dev, "Will reset the machine !\n"); +} + +static const struct file_operations nuc900wdt_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .unlocked_ioctl = nuc900_wdt_ioctl, + .open = nuc900_wdt_open, + .release = nuc900_wdt_close, + .write = nuc900_wdt_write, +}; + +static struct miscdevice nuc900wdt_miscdev = { + .minor = WATCHDOG_MINOR, + .name = "watchdog", + .fops = &nuc900wdt_fops, +}; + +static int __devinit nuc900wdt_probe(struct platform_device *pdev) +{ + int ret = 0; + + nuc900_wdt = kzalloc(sizeof(struct nuc900_wdt), GFP_KERNEL); + if (!nuc900_wdt) + return -ENOMEM; + + nuc900_wdt->pdev = pdev; + + spin_lock_init(&nuc900_wdt->wdt_lock); + + nuc900_wdt->res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (nuc900_wdt->res == NULL) { + dev_err(&pdev->dev, "no memory resource specified\n"); + ret = -ENOENT; + goto err_get; + } + + if (!request_mem_region(nuc900_wdt->res->start, + resource_size(nuc900_wdt->res), pdev->name)) { + dev_err(&pdev->dev, "failed to get memory region\n"); + ret = -ENOENT; + goto err_get; + } + + nuc900_wdt->wdt_base = ioremap(nuc900_wdt->res->start, + resource_size(nuc900_wdt->res)); + if (nuc900_wdt->wdt_base == NULL) { + dev_err(&pdev->dev, "failed to ioremap() region\n"); + ret = -EINVAL; + goto err_req; + } + + nuc900_wdt->wdt_clock = clk_get(&pdev->dev, NULL); + if (IS_ERR(nuc900_wdt->wdt_clock)) { + dev_err(&pdev->dev, "failed to find watchdog clock source\n"); + ret = PTR_ERR(nuc900_wdt->wdt_clock); + goto err_map; + } + + clk_enable(nuc900_wdt->wdt_clock); + + setup_timer(&nuc900_wdt->timer, nuc900_wdt_timer_ping, 0); + + if (misc_register(&nuc900wdt_miscdev)) { + dev_err(&pdev->dev, "err register miscdev on minor=%d (%d)\n", + WATCHDOG_MINOR, ret); + goto err_clk; + } + + return 0; + +err_clk: + clk_disable(nuc900_wdt->wdt_clock); + clk_put(nuc900_wdt->wdt_clock); +err_map: + iounmap(nuc900_wdt->wdt_base); +err_req: + release_mem_region(nuc900_wdt->res->start, + resource_size(nuc900_wdt->res)); +err_get: + kfree(nuc900_wdt); + return ret; +} + +static int __devexit nuc900wdt_remove(struct platform_device *pdev) +{ + misc_deregister(&nuc900wdt_miscdev); + + clk_disable(nuc900_wdt->wdt_clock); + clk_put(nuc900_wdt->wdt_clock); + + iounmap(nuc900_wdt->wdt_base); + + release_mem_region(nuc900_wdt->res->start, + resource_size(nuc900_wdt->res)); + + kfree(nuc900_wdt); + + return 0; +} + +static struct platform_driver nuc900wdt_driver = { + .probe = nuc900wdt_probe, + .remove = __devexit_p(nuc900wdt_remove), + .driver = { + .name = "nuc900-wdt", + .owner = THIS_MODULE, + }, +}; + +static int __init nuc900_wdt_init(void) +{ + return platform_driver_register(&nuc900wdt_driver); +} + +static void __exit nuc900_wdt_exit(void) +{ + platform_driver_unregister(&nuc900wdt_driver); +} + +module_init(nuc900_wdt_init); +module_exit(nuc900_wdt_exit); + +MODULE_AUTHOR("Wan ZongShun <mcuos.com@gmail.com>"); +MODULE_DESCRIPTION("Watchdog driver for NUC900"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); +MODULE_ALIAS("platform:nuc900-wdt"); |