| /* |
| * Blackfin On-Chip Watchdog Driver |
| * |
| * Originally based on softdog.c |
| * Copyright 2006-2010 Analog Devices Inc. |
| * Copyright 2006-2007 Michele d'Amico |
| * Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk> |
| * |
| * Enter bugs at http://blackfin.uclinux.org/ |
| * |
| * Licensed under the GPL-2 or later. |
| */ |
| |
| #include <linux/platform_device.h> |
| #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/notifier.h> |
| #include <linux/reboot.h> |
| #include <linux/init.h> |
| #include <linux/interrupt.h> |
| #include <linux/uaccess.h> |
| #include <asm/blackfin.h> |
| |
| #define stamp(fmt, args...) \ |
| pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args) |
| #define stampit() stamp("here i am") |
| #define pr_devinit(fmt, args...) \ |
| ({ static const __devinitconst char __fmt[] = fmt; \ |
| printk(__fmt, ## args); }) |
| #define pr_init(fmt, args...) \ |
| ({ static const __initconst char __fmt[] = fmt; \ |
| printk(__fmt, ## args); }) |
| |
| #define WATCHDOG_NAME "bfin-wdt" |
| #define PFX WATCHDOG_NAME ": " |
| |
| /* The BF561 has two watchdogs (one per core), but since Linux |
| * only runs on core A, we'll just work with that one. |
| */ |
| #ifdef BF561_FAMILY |
| # define bfin_read_WDOG_CTL() bfin_read_WDOGA_CTL() |
| # define bfin_read_WDOG_CNT() bfin_read_WDOGA_CNT() |
| # define bfin_read_WDOG_STAT() bfin_read_WDOGA_STAT() |
| # define bfin_write_WDOG_CTL(x) bfin_write_WDOGA_CTL(x) |
| # define bfin_write_WDOG_CNT(x) bfin_write_WDOGA_CNT(x) |
| # define bfin_write_WDOG_STAT(x) bfin_write_WDOGA_STAT(x) |
| #endif |
| |
| /* Bit in SWRST that indicates boot caused by watchdog */ |
| #define SWRST_RESET_WDOG 0x4000 |
| |
| /* Bit in WDOG_CTL that indicates watchdog has expired (WDR0) */ |
| #define WDOG_EXPIRED 0x8000 |
| |
| /* Masks for WDEV field in WDOG_CTL register */ |
| #define ICTL_RESET 0x0 |
| #define ICTL_NMI 0x2 |
| #define ICTL_GPI 0x4 |
| #define ICTL_NONE 0x6 |
| #define ICTL_MASK 0x6 |
| |
| /* Masks for WDEN field in WDOG_CTL register */ |
| #define WDEN_MASK 0x0FF0 |
| #define WDEN_ENABLE 0x0000 |
| #define WDEN_DISABLE 0x0AD0 |
| |
| /* some defaults */ |
| #define WATCHDOG_TIMEOUT 20 |
| |
| static unsigned int timeout = WATCHDOG_TIMEOUT; |
| static int nowayout = WATCHDOG_NOWAYOUT; |
| static const struct watchdog_info bfin_wdt_info; |
| static unsigned long open_check; |
| static char expect_close; |
| static DEFINE_SPINLOCK(bfin_wdt_spinlock); |
| |
| /** |
| * bfin_wdt_keepalive - Keep the Userspace Watchdog Alive |
| * |
| * The Userspace watchdog got a KeepAlive: schedule the next timeout. |
| */ |
| static int bfin_wdt_keepalive(void) |
| { |
| stampit(); |
| bfin_write_WDOG_STAT(0); |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_stop - Stop the Watchdog |
| * |
| * Stops the on-chip watchdog. |
| */ |
| static int bfin_wdt_stop(void) |
| { |
| stampit(); |
| bfin_write_WDOG_CTL(WDEN_DISABLE); |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_start - Start the Watchdog |
| * |
| * Starts the on-chip watchdog. Automatically loads WDOG_CNT |
| * into WDOG_STAT for us. |
| */ |
| static int bfin_wdt_start(void) |
| { |
| stampit(); |
| bfin_write_WDOG_CTL(WDEN_ENABLE | ICTL_RESET); |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_running - Check Watchdog status |
| * |
| * See if the watchdog is running. |
| */ |
| static int bfin_wdt_running(void) |
| { |
| stampit(); |
| return ((bfin_read_WDOG_CTL() & WDEN_MASK) != WDEN_DISABLE); |
| } |
| |
| /** |
| * bfin_wdt_set_timeout - Set the Userspace Watchdog timeout |
| * @t: new timeout value (in seconds) |
| * |
| * Translate the specified timeout in seconds into System Clock |
| * terms which is what the on-chip Watchdog requires. |
| */ |
| static int bfin_wdt_set_timeout(unsigned long t) |
| { |
| u32 cnt, max_t, sclk; |
| unsigned long flags; |
| |
| sclk = get_sclk(); |
| max_t = -1 / sclk; |
| cnt = t * sclk; |
| stamp("maxtimeout=%us newtimeout=%lus (cnt=%#x)", max_t, t, cnt); |
| |
| if (t > max_t) { |
| printk(KERN_WARNING PFX "timeout value is too large\n"); |
| return -EINVAL; |
| } |
| |
| spin_lock_irqsave(&bfin_wdt_spinlock, flags); |
| { |
| int run = bfin_wdt_running(); |
| bfin_wdt_stop(); |
| bfin_write_WDOG_CNT(cnt); |
| if (run) |
| bfin_wdt_start(); |
| } |
| spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); |
| |
| timeout = t; |
| |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_open - Open the Device |
| * @inode: inode of device |
| * @file: file handle of device |
| * |
| * Watchdog device is opened and started. |
| */ |
| static int bfin_wdt_open(struct inode *inode, struct file *file) |
| { |
| stampit(); |
| |
| if (test_and_set_bit(0, &open_check)) |
| return -EBUSY; |
| |
| if (nowayout) |
| __module_get(THIS_MODULE); |
| |
| bfin_wdt_keepalive(); |
| bfin_wdt_start(); |
| |
| return nonseekable_open(inode, file); |
| } |
| |
| /** |
| * bfin_wdt_close - Close the Device |
| * @inode: inode of device |
| * @file: file handle of device |
| * |
| * Watchdog device is closed and stopped. |
| */ |
| static int bfin_wdt_release(struct inode *inode, struct file *file) |
| { |
| stampit(); |
| |
| if (expect_close == 42) |
| bfin_wdt_stop(); |
| else { |
| printk(KERN_CRIT PFX |
| "Unexpected close, not stopping watchdog!\n"); |
| bfin_wdt_keepalive(); |
| } |
| expect_close = 0; |
| clear_bit(0, &open_check); |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_write - Write to Device |
| * @file: file handle of device |
| * @buf: buffer to write |
| * @count: length of buffer |
| * @ppos: offset |
| * |
| * Pings the watchdog on write. |
| */ |
| static ssize_t bfin_wdt_write(struct file *file, const char __user *data, |
| size_t len, loff_t *ppos) |
| { |
| stampit(); |
| |
| if (len) { |
| if (!nowayout) { |
| size_t i; |
| |
| /* In case it was set long ago */ |
| expect_close = 0; |
| |
| for (i = 0; i != len; i++) { |
| char c; |
| if (get_user(c, data + i)) |
| return -EFAULT; |
| if (c == 'V') |
| expect_close = 42; |
| } |
| } |
| bfin_wdt_keepalive(); |
| } |
| |
| return len; |
| } |
| |
| /** |
| * bfin_wdt_ioctl - Query Device |
| * @file: file handle of device |
| * @cmd: watchdog command |
| * @arg: argument |
| * |
| * Query basic information from the device or ping it, as outlined by the |
| * watchdog API. |
| */ |
| static long bfin_wdt_ioctl(struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| void __user *argp = (void __user *)arg; |
| int __user *p = argp; |
| |
| stampit(); |
| |
| switch (cmd) { |
| case WDIOC_GETSUPPORT: |
| if (copy_to_user(argp, &bfin_wdt_info, sizeof(bfin_wdt_info))) |
| return -EFAULT; |
| else |
| return 0; |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| return put_user(!!(_bfin_swrst & SWRST_RESET_WDOG), p); |
| case WDIOC_SETOPTIONS: { |
| unsigned long flags; |
| int options, ret = -EINVAL; |
| |
| if (get_user(options, p)) |
| return -EFAULT; |
| |
| spin_lock_irqsave(&bfin_wdt_spinlock, flags); |
| if (options & WDIOS_DISABLECARD) { |
| bfin_wdt_stop(); |
| ret = 0; |
| } |
| if (options & WDIOS_ENABLECARD) { |
| bfin_wdt_start(); |
| ret = 0; |
| } |
| spin_unlock_irqrestore(&bfin_wdt_spinlock, flags); |
| return ret; |
| } |
| case WDIOC_KEEPALIVE: |
| bfin_wdt_keepalive(); |
| return 0; |
| case WDIOC_SETTIMEOUT: { |
| int new_timeout; |
| |
| if (get_user(new_timeout, p)) |
| return -EFAULT; |
| if (bfin_wdt_set_timeout(new_timeout)) |
| return -EINVAL; |
| } |
| /* Fall */ |
| case WDIOC_GETTIMEOUT: |
| return put_user(timeout, p); |
| default: |
| return -ENOTTY; |
| } |
| } |
| |
| /** |
| * bfin_wdt_notify_sys - Notifier Handler |
| * @this: notifier block |
| * @code: notifier event |
| * @unused: unused |
| * |
| * Handles specific events, such as turning off the watchdog during a |
| * shutdown event. |
| */ |
| static int bfin_wdt_notify_sys(struct notifier_block *this, |
| unsigned long code, void *unused) |
| { |
| stampit(); |
| |
| if (code == SYS_DOWN || code == SYS_HALT) |
| bfin_wdt_stop(); |
| |
| return NOTIFY_DONE; |
| } |
| |
| #ifdef CONFIG_PM |
| static int state_before_suspend; |
| |
| /** |
| * bfin_wdt_suspend - suspend the watchdog |
| * @pdev: device being suspended |
| * @state: requested suspend state |
| * |
| * Remember if the watchdog was running and stop it. |
| * TODO: is this even right? Doesn't seem to be any |
| * standard in the watchdog world ... |
| */ |
| static int bfin_wdt_suspend(struct platform_device *pdev, pm_message_t state) |
| { |
| stampit(); |
| |
| state_before_suspend = bfin_wdt_running(); |
| bfin_wdt_stop(); |
| |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_resume - resume the watchdog |
| * @pdev: device being resumed |
| * |
| * If the watchdog was running, turn it back on. |
| */ |
| static int bfin_wdt_resume(struct platform_device *pdev) |
| { |
| stampit(); |
| |
| if (state_before_suspend) { |
| bfin_wdt_set_timeout(timeout); |
| bfin_wdt_start(); |
| } |
| |
| return 0; |
| } |
| #else |
| # define bfin_wdt_suspend NULL |
| # define bfin_wdt_resume NULL |
| #endif |
| |
| static const struct file_operations bfin_wdt_fops = { |
| .owner = THIS_MODULE, |
| .llseek = no_llseek, |
| .write = bfin_wdt_write, |
| .unlocked_ioctl = bfin_wdt_ioctl, |
| .open = bfin_wdt_open, |
| .release = bfin_wdt_release, |
| }; |
| |
| static struct miscdevice bfin_wdt_miscdev = { |
| .minor = WATCHDOG_MINOR, |
| .name = "watchdog", |
| .fops = &bfin_wdt_fops, |
| }; |
| |
| static const struct watchdog_info bfin_wdt_info = { |
| .identity = "Blackfin Watchdog", |
| .options = WDIOF_SETTIMEOUT | |
| WDIOF_KEEPALIVEPING | |
| WDIOF_MAGICCLOSE, |
| }; |
| |
| static struct notifier_block bfin_wdt_notifier = { |
| .notifier_call = bfin_wdt_notify_sys, |
| }; |
| |
| /** |
| * bfin_wdt_probe - Initialize module |
| * |
| * Registers the misc device and notifier handler. Actual device |
| * initialization is handled by bfin_wdt_open(). |
| */ |
| static int __devinit bfin_wdt_probe(struct platform_device *pdev) |
| { |
| int ret; |
| |
| ret = register_reboot_notifier(&bfin_wdt_notifier); |
| if (ret) { |
| pr_devinit(KERN_ERR PFX |
| "cannot register reboot notifier (err=%d)\n", ret); |
| return ret; |
| } |
| |
| ret = misc_register(&bfin_wdt_miscdev); |
| if (ret) { |
| pr_devinit(KERN_ERR PFX |
| "cannot register miscdev on minor=%d (err=%d)\n", |
| WATCHDOG_MINOR, ret); |
| unregister_reboot_notifier(&bfin_wdt_notifier); |
| return ret; |
| } |
| |
| pr_devinit(KERN_INFO PFX "initialized: timeout=%d sec (nowayout=%d)\n", |
| timeout, nowayout); |
| |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_remove - Initialize module |
| * |
| * Unregisters the misc device and notifier handler. Actual device |
| * deinitialization is handled by bfin_wdt_close(). |
| */ |
| static int __devexit bfin_wdt_remove(struct platform_device *pdev) |
| { |
| misc_deregister(&bfin_wdt_miscdev); |
| unregister_reboot_notifier(&bfin_wdt_notifier); |
| return 0; |
| } |
| |
| static struct platform_device *bfin_wdt_device; |
| |
| static struct platform_driver bfin_wdt_driver = { |
| .probe = bfin_wdt_probe, |
| .remove = __devexit_p(bfin_wdt_remove), |
| .suspend = bfin_wdt_suspend, |
| .resume = bfin_wdt_resume, |
| .driver = { |
| .name = WATCHDOG_NAME, |
| .owner = THIS_MODULE, |
| }, |
| }; |
| |
| /** |
| * bfin_wdt_init - Initialize module |
| * |
| * Checks the module params and registers the platform device & driver. |
| * Real work is in the platform probe function. |
| */ |
| static int __init bfin_wdt_init(void) |
| { |
| int ret; |
| |
| stampit(); |
| |
| /* Check that the timeout value is within range */ |
| if (bfin_wdt_set_timeout(timeout)) |
| return -EINVAL; |
| |
| /* Since this is an on-chip device and needs no board-specific |
| * resources, we'll handle all the platform device stuff here. |
| */ |
| ret = platform_driver_register(&bfin_wdt_driver); |
| if (ret) { |
| pr_init(KERN_ERR PFX "unable to register driver\n"); |
| return ret; |
| } |
| |
| bfin_wdt_device = platform_device_register_simple(WATCHDOG_NAME, |
| -1, NULL, 0); |
| if (IS_ERR(bfin_wdt_device)) { |
| pr_init(KERN_ERR PFX "unable to register device\n"); |
| platform_driver_unregister(&bfin_wdt_driver); |
| return PTR_ERR(bfin_wdt_device); |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * bfin_wdt_exit - Deinitialize module |
| * |
| * Back out the platform device & driver steps. Real work is in the |
| * platform remove function. |
| */ |
| static void __exit bfin_wdt_exit(void) |
| { |
| platform_device_unregister(bfin_wdt_device); |
| platform_driver_unregister(&bfin_wdt_driver); |
| } |
| |
| module_init(bfin_wdt_init); |
| module_exit(bfin_wdt_exit); |
| |
| MODULE_AUTHOR("Michele d'Amico, Mike Frysinger <vapier@gentoo.org>"); |
| MODULE_DESCRIPTION("Blackfin Watchdog Device Driver"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |
| |
| module_param(timeout, uint, 0); |
| MODULE_PARM_DESC(timeout, |
| "Watchdog timeout in seconds. (1<=timeout<=((2^32)/SCLK), default=" |
| __MODULE_STRING(WATCHDOG_TIMEOUT) ")"); |
| |
| module_param(nowayout, int, 0); |
| MODULE_PARM_DESC(nowayout, |
| "Watchdog cannot be stopped once started (default=" |
| __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); |