/* * Watchdog driver for Atmel AT32AP700X devices * * Copyright (C) 2005-2006 Atmel Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #define TIMEOUT_MIN 1 #define TIMEOUT_MAX 2 #define TIMEOUT_DEFAULT TIMEOUT_MAX /* module parameters */ static int timeout = TIMEOUT_DEFAULT; module_param(timeout, int, 0); MODULE_PARM_DESC(timeout, "Timeout value. Limited to be 1 or 2 seconds. (default=" __MODULE_STRING(TIMEOUT_DEFAULT) ")"); 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) ")"); /* Watchdog registers and write/read macro */ #define WDT_CTRL 0x00 #define WDT_CTRL_EN 0 #define WDT_CTRL_PSEL 8 #define WDT_CTRL_KEY 24 #define WDT_CLR 0x04 #define WDT_BIT(name) (1 << WDT_##name) #define WDT_BF(name, value) ((value) << WDT_##name) #define wdt_readl(dev, reg) \ __raw_readl((dev)->regs + WDT_##reg) #define wdt_writel(dev, reg, value) \ __raw_writel((value), (dev)->regs + WDT_##reg) struct wdt_at32ap700x { void __iomem *regs; spinlock_t io_lock; int timeout; unsigned long users; struct miscdevice miscdev; }; static struct wdt_at32ap700x *wdt; static char expect_release; /* * Disable the watchdog. */ static inline void at32_wdt_stop(void) { unsigned long psel; spin_lock(&wdt->io_lock); psel = wdt_readl(wdt, CTRL) & WDT_BF(CTRL_PSEL, 0x0f); wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0x55)); wdt_writel(wdt, CTRL, psel | WDT_BF(CTRL_KEY, 0xaa)); spin_unlock(&wdt->io_lock); } /* * Enable and reset the watchdog. */ static inline void at32_wdt_start(void) { /* 0xf is 2^16 divider = 2 sec, 0xe is 2^15 divider = 1 sec */ unsigned long psel = (wdt->timeout > 1) ? 0xf : 0xe; spin_lock(&wdt->io_lock); wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | WDT_BF(CTRL_PSEL, psel) | WDT_BF(CTRL_KEY, 0x55)); wdt_writel(wdt, CTRL, WDT_BIT(CTRL_EN) | WDT_BF(CTRL_PSEL, psel) | WDT_BF(CTRL_KEY, 0xaa)); spin_unlock(&wdt->io_lock); } /* * Pat the watchdog timer. */ static inline void at32_wdt_pat(void) { spin_lock(&wdt->io_lock); wdt_writel(wdt, CLR, 0x42); spin_unlock(&wdt->io_lock); } /* * Watchdog device is opened, and watchdog starts running. */ static int at32_wdt_open(struct inode *inode, struct file *file) { if (test_and_set_bit(1, &wdt->users)) return -EBUSY; at32_wdt_start(); return nonseekable_open(inode, file); } /* * Close the watchdog device. */ static int at32_wdt_close(struct inode *inode, struct file *file) { if (expect_release == 42) { at32_wdt_stop(); } else { dev_dbg(wdt->miscdev.parent, "Unexpected close, not stopping watchdog!\n"); at32_wdt_pat(); } clear_bit(1, &wdt->users); expect_release = 0; return 0; } /* * Change the watchdog time interval. */ static int at32_wdt_settimeout(int time) { /* * All counting occurs at 1 / SLOW_CLOCK (32 kHz) and max prescaler is * 2 ^ 16 allowing up to 2 seconds timeout. */ if ((time < TIMEOUT_MIN) || (time > TIMEOUT_MAX)) return -EINVAL; /* * Set new watchdog time. It will be used when at32_wdt_start() is * called. */ wdt->timeout = time; return 0; } static struct watchdog_info at32_wdt_info = { .identity = "at32ap700x watchdog", .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, }; /* * Handle commands from user-space. */ static int at32_wdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; int time; void __user *argp = (void __user *)arg; int __user *p = argp; switch (cmd) { case WDIOC_KEEPALIVE: at32_wdt_pat(); ret = 0; break; case WDIOC_GETSUPPORT: ret = copy_to_user(argp, &at32_wdt_info, sizeof(at32_wdt_info)) ? -EFAULT : 0; break; case WDIOC_SETTIMEOUT: ret = get_user(time, p); if (ret) break; ret = at32_wdt_settimeout(time); if (ret) break; /* Enable new time value */ at32_wdt_start(); /* fall through */ case WDIOC_GETTIMEOUT: ret = put_user(wdt->timeout, p); break; case WDIOC_GETSTATUS: /* fall through */ case WDIOC_GETBOOTSTATUS: ret = put_user(0, p); break; case WDIOC_SETOPTIONS: ret = get_user(time, p); if (ret) break; if (time & WDIOS_DISABLECARD) at32_wdt_stop(); if (time & WDIOS_ENABLECARD) at32_wdt_start(); ret = 0; break; } return ret; } static ssize_t at32_wdt_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) { /* See if we got the magic character 'V' and reload the timer */ if (len) { if (!nowayout) { size_t i; /* * note: just in case someone wrote the magic * character five months ago... */ expect_release = 0; /* * scan to see whether or not we got the magic * character */ for (i = 0; i != len; i++) { char c; if (get_user(c, data+i)) return -EFAULT; if (c == 'V') expect_release = 42; } } /* someone wrote to us, we should pat the watchdog */ at32_wdt_pat(); } return len; } static const struct file_operations at32_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, .ioctl = at32_wdt_ioctl, .open = at32_wdt_open, .release = at32_wdt_close, .write = at32_wdt_write, }; static int __init at32_wdt_probe(struct platform_device *pdev) { struct resource *regs; int ret; if (wdt) { dev_dbg(&pdev->dev, "only 1 wdt instance supported.\n"); return -EBUSY; } regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!regs) { dev_dbg(&pdev->dev, "missing mmio resource\n"); return -ENXIO; } wdt = kzalloc(sizeof(struct wdt_at32ap700x), GFP_KERNEL); if (!wdt) { dev_dbg(&pdev->dev, "no memory for wdt structure\n"); return -ENOMEM; } wdt->regs = ioremap(regs->start, regs->end - regs->start + 1); if (!wdt->regs) { ret = -ENOMEM; dev_dbg(&pdev->dev, "could not map I/O memory\n"); goto err_free; } spin_lock_init(&wdt->io_lock); wdt->users = 0; wdt->miscdev.minor = WATCHDOG_MINOR; wdt->miscdev.name = "watchdog"; wdt->miscdev.fops = &at32_wdt_fops; if (at32_wdt_settimeout(timeout)) { at32_wdt_settimeout(TIMEOUT_DEFAULT); dev_dbg(&pdev->dev, "default timeout invalid, set to %d sec.\n", TIMEOUT_DEFAULT); } ret = misc_register(&wdt->miscdev); if (ret) { dev_dbg(&pdev->dev, "failed to register wdt miscdev\n"); goto err_iounmap; } platform_set_drvdata(pdev, wdt); wdt->miscdev.parent = &pdev->dev; dev_info(&pdev->dev, "AT32AP700X WDT at 0x%p, timeout %d sec (nowayout=%d)\n", wdt->regs, wdt->timeout, nowayout); return 0; err_iounmap: iounmap(wdt->regs); err_free: kfree(wdt); wdt = NULL; return ret; } static int __exit at32_wdt_remove(struct platform_device *pdev) { if (wdt && platform_get_drvdata(pdev) == wdt) { /* Stop the timer before we leave */ if (!nowayout) at32_wdt_stop(); misc_deregister(&wdt->miscdev); iounmap(wdt->regs); kfree(wdt); wdt = NULL; platform_set_drvdata(pdev, NULL); } return 0; } static void at32_wdt_shutdown(struct platform_device *pdev) { at32_wdt_stop(); } #ifdef CONFIG_PM static int at32_wdt_suspend(struct platform_device *pdev, pm_message_t message) { at32_wdt_stop(); return 0; } static int at32_wdt_resume(struct platform_device *pdev) { if (wdt->users) at32_wdt_start(); return 0; } #else #define at32_wdt_suspend NULL #define at32_wdt_resume NULL #endif static struct platform_driver at32_wdt_driver = { .remove = __exit_p(at32_wdt_remove), .suspend = at32_wdt_suspend, .resume = at32_wdt_resume, .driver = { .name = "at32_wdt", .owner = THIS_MODULE, }, .shutdown = at32_wdt_shutdown, }; static int __init at32_wdt_init(void) { return platform_driver_probe(&at32_wdt_driver, at32_wdt_probe); } module_init(at32_wdt_init); static void __exit at32_wdt_exit(void) { platform_driver_unregister(&at32_wdt_driver); } module_exit(at32_wdt_exit); MODULE_AUTHOR("Hans-Christian Egtvedt "); MODULE_DESCRIPTION("Watchdog driver for Atmel AT32AP700X"); MODULE_LICENSE("GPL"); MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);