* 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 <linux/init.h>
#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)
void __iomem *regs;
spinlock_t io_lock;
int timeout;
+ int boot_status;
unsigned long users;
struct miscdevice miscdev;
};
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);
return 0;
}
-static struct watchdog_info at32_wdt_info = {
+/*
+ * 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 const struct watchdog_info at32_wdt_info = {
.identity = "at32ap700x watchdog",
.options = WDIOF_SETTIMEOUT |
WDIOF_KEEPALIVEPING |
/*
* 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;
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);
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;
*/
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;
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,
return -ENOMEM;
}
- wdt->regs = ioremap(regs->start, regs->end - regs->start + 1);
+ wdt->regs = ioremap(regs->start, resource_size(regs));
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->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;
wdt = NULL;
platform_set_drvdata(pdev, NULL);
}
-
return 0;
}
#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,
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff