X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fwatchdog%2Fat32ap700x_wdt.c;h=e8ae638e5804ceb600acce099555127161848191;hb=f2d7499be1b1fe1cd8a5e6a01c1f44173894a241;hp=54a516169d070e6d1b33625b4dc75bb1e451d3bf;hpb=0c326331c8b107abc0a160e8899d749150b8f76a;p=linux-2.6 diff --git a/drivers/watchdog/at32ap700x_wdt.c b/drivers/watchdog/at32ap700x_wdt.c index 54a516169d..e8ae638e58 100644 --- a/drivers/watchdog/at32ap700x_wdt.c +++ b/drivers/watchdog/at32ap700x_wdt.c @@ -6,6 +6,19 @@ * 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. + * + * + * Errata: WDT Clear is blocked after WDT Reset + * + * A watchdog timer event will, after reset, block writes to the WDT_CLEAR + * register, preventing the program to clear the next Watchdog Timer Reset. + * + * If you still want to use the WDT after a WDT reset a small code can be + * insterted at the startup checking the AVR32_PM.rcause register for WDT reset + * and use a GPIO pin to reset the system. This method requires that one of the + * GPIO pins are available and connected externally to the RESET_N pin. After + * the GPIO pin has pulled down the reset line the GPIO will be reset and leave + * the pin tristated with pullup. */ #include @@ -44,6 +57,13 @@ MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" #define WDT_CLR 0x04 +#define WDT_RCAUSE 0x10 +#define WDT_RCAUSE_POR 0 +#define WDT_RCAUSE_EXT 2 +#define WDT_RCAUSE_WDT 3 +#define WDT_RCAUSE_JTAG 4 +#define WDT_RCAUSE_SERP 5 + #define WDT_BIT(name) (1 << WDT_##name) #define WDT_BF(name, value) ((value) << WDT_##name) @@ -56,6 +76,7 @@ struct wdt_at32ap700x { void __iomem *regs; spinlock_t io_lock; int timeout; + int boot_status; unsigned long users; struct miscdevice miscdev; }; @@ -126,7 +147,7 @@ static int at32_wdt_close(struct inode *inode, struct file *file) at32_wdt_stop(); } else { dev_dbg(wdt->miscdev.parent, - "Unexpected close, not stopping watchdog!\n"); + "unexpected close, not stopping watchdog!\n"); at32_wdt_pat(); } clear_bit(1, &wdt->users); @@ -154,6 +175,33 @@ static int at32_wdt_settimeout(int time) return 0; } +/* + * Get the watchdog status. + */ +static int at32_wdt_get_status(void) +{ + int rcause; + int status = 0; + + rcause = wdt_readl(wdt, RCAUSE); + + switch (rcause) { + case WDT_BIT(RCAUSE_EXT): + status = WDIOF_EXTERN1; + break; + case WDT_BIT(RCAUSE_WDT): + status = WDIOF_CARDRESET; + break; + case WDT_BIT(RCAUSE_POR): /* fall through */ + case WDT_BIT(RCAUSE_JTAG): /* fall through */ + case WDT_BIT(RCAUSE_SERP): /* fall through */ + default: + break; + } + + return status; +} + static struct watchdog_info at32_wdt_info = { .identity = "at32ap700x watchdog", .options = WDIOF_SETTIMEOUT | @@ -164,8 +212,8 @@ static struct watchdog_info at32_wdt_info = { /* * Handle commands from user-space. */ -static int at32_wdt_ioctl(struct inode *inode, struct file *file, - unsigned int cmd, unsigned long arg) +static long at32_wdt_ioctl(struct file *file, + unsigned int cmd, unsigned long arg) { int ret = -ENOTTY; int time; @@ -173,30 +221,15 @@ static int at32_wdt_ioctl(struct inode *inode, struct file *file, 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); + case WDIOC_GETSTATUS: + ret = put_user(0, p); break; - case WDIOC_GETSTATUS: /* fall through */ case WDIOC_GETBOOTSTATUS: - ret = put_user(0, p); + ret = put_user(wdt->boot_status, p); break; case WDIOC_SETOPTIONS: ret = get_user(time, p); @@ -208,6 +241,23 @@ static int at32_wdt_ioctl(struct inode *inode, struct file *file, at32_wdt_start(); ret = 0; break; + case WDIOC_KEEPALIVE: + at32_wdt_pat(); + ret = 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; } return ret; @@ -233,7 +283,7 @@ static ssize_t at32_wdt_write(struct file *file, const char __user *data, */ for (i = 0; i != len; i++) { char c; - if (get_user(c, data+i)) + if (get_user(c, data + i)) return -EFAULT; if (c == 'V') expect_release = 42; @@ -248,7 +298,7 @@ static ssize_t at32_wdt_write(struct file *file, const char __user *data, static const struct file_operations at32_wdt_fops = { .owner = THIS_MODULE, .llseek = no_llseek, - .ioctl = at32_wdt_ioctl, + .unlocked_ioctl = at32_wdt_ioctl, .open = at32_wdt_open, .release = at32_wdt_close, .write = at32_wdt_write, @@ -282,8 +332,19 @@ static int __init at32_wdt_probe(struct platform_device *pdev) dev_dbg(&pdev->dev, "could not map I/O memory\n"); goto err_free; } + spin_lock_init(&wdt->io_lock); - wdt->users = 0; + wdt->boot_status = at32_wdt_get_status(); + + /* Work-around for watchdog silicon errata. */ + if (wdt->boot_status & WDIOF_CARDRESET) { + dev_info(&pdev->dev, "CPU must be reset with external " + "reset or POR due to silicon errata.\n"); + ret = -EIO; + goto err_iounmap; + } else { + wdt->users = 0; + } wdt->miscdev.minor = WATCHDOG_MINOR; wdt->miscdev.name = "watchdog"; wdt->miscdev.fops = &at32_wdt_fops; @@ -330,7 +391,6 @@ static int __exit at32_wdt_remove(struct platform_device *pdev) wdt = NULL; platform_set_drvdata(pdev, NULL); } - return 0; } @@ -357,6 +417,9 @@ static int at32_wdt_resume(struct platform_device *pdev) #define at32_wdt_resume NULL #endif +/* work with hotplug and coldplug */ +MODULE_ALIAS("platform:at32_wdt"); + static struct platform_driver at32_wdt_driver = { .remove = __exit_p(at32_wdt_remove), .suspend = at32_wdt_suspend,