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bcm2708 watchdog driver

Signed-off-by: popcornmix <popcornmix@gmail.com>
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1 parent 031ee3e commit 7ff2699415531e8cc583921d5ee9b48f8df25b82 @popcornmix popcornmix committed with Dom Cobley Jan 17, 2012
Showing with 392 additions and 0 deletions.
  1. +6 −0 drivers/watchdog/Kconfig
  2. +1 −0 drivers/watchdog/Makefile
  3. +385 −0 drivers/watchdog/bcm2708_wdog.c
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6 drivers/watchdog/Kconfig
@@ -343,6 +343,12 @@ config IMX2_WDT
To compile this driver as a module, choose M here: the
module will be called imx2_wdt.
+config BCM2708_WDT
+ tristate "BCM2708 Watchdog"
+ depends on ARCH_BCM2708
+ help
+ Enables BCM2708 watchdog support.
+
# AVR32 Architecture
config AT32AP700X_WDT
View
1 drivers/watchdog/Makefile
@@ -53,6 +53,7 @@ obj-$(CONFIG_STMP3XXX_WATCHDOG) += stmp3xxx_wdt.o
obj-$(CONFIG_NUC900_WATCHDOG) += nuc900_wdt.o
obj-$(CONFIG_TS72XX_WATCHDOG) += ts72xx_wdt.o
obj-$(CONFIG_IMX2_WDT) += imx2_wdt.o
+obj-$(CONFIG_BCM2708_WDT) += bcm2708_wdog.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
View
385 drivers/watchdog/bcm2708_wdog.c
@@ -0,0 +1,385 @@
+/*
+ * Broadcom BCM2708 watchdog driver.
+ *
+ * (c) Copyright 2010 Broadcom Europe Ltd
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ *
+ * BCM2708 watchdog driver. Loosely based on wdt driver.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/types.h>
+#include <linux/miscdevice.h>
+#include <linux/watchdog.h>
+#include <linux/fs.h>
+#include <linux/ioport.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
+#include <mach/platform.h>
+
+#include <asm/system.h>
+
+#define SECS_TO_WDOG_TICKS(x) ((x) << 16)
+#define WDOG_TICKS_TO_SECS(x) ((x) >> 16)
+
+static unsigned long wdog_is_open;
+static uint32_t wdog_ticks; /* Ticks to load into wdog timer */
+static char expect_close;
+
+/*
+ * Module parameters
+ */
+
+#define WD_TIMO 10 /* Default heartbeat = 60 seconds */
+static int heartbeat = WD_TIMO; /* Heartbeat in seconds */
+
+module_param(heartbeat, int, 0);
+MODULE_PARM_DESC(heartbeat,
+ "Watchdog heartbeat in seconds. (0 < heartbeat < 65536, default="
+ __MODULE_STRING(WD_TIMO) ")");
+
+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) ")");
+
+static DEFINE_SPINLOCK(wdog_lock);
+
+/**
+ * Start the watchdog driver.
+ */
+
+static int wdog_start(unsigned long timeout)
+{
+ uint32_t cur;
+ unsigned long flags;
+ spin_lock_irqsave(&wdog_lock, flags);
+
+ /* enable the watchdog */
+ iowrite32(PM_PASSWORD | (timeout & PM_WDOG_TIME_SET),
+ __io_address(PM_WDOG));
+ cur = ioread32(__io_address(PM_RSTC));
+ iowrite32(PM_PASSWORD | (cur & PM_RSTC_WRCFG_CLR) |
+ PM_RSTC_WRCFG_FULL_RESET, __io_address(PM_RSTC));
+
+ spin_unlock_irqrestore(&wdog_lock, flags);
+ return 0;
+}
+
+/**
+ * Stop the watchdog driver.
+ */
+
+static int wdog_stop(void)
+{
+ iowrite32(PM_PASSWORD | PM_RSTC_RESET, __io_address(PM_RSTC));
+ printk(KERN_INFO "watchdog stopped\n");
+ return 0;
+}
+
+/**
+ * Reload counter one with the watchdog heartbeat. We don't bother
+ * reloading the cascade counter.
+ */
+
+static void wdog_ping(void)
+{
+ wdog_start(wdog_ticks);
+}
+
+/**
+ * @t: the new heartbeat value that needs to be set.
+ *
+ * Set a new heartbeat value for the watchdog device. If the heartbeat
+ * value is incorrect we keep the old value and return -EINVAL. If
+ * successful we return 0.
+ */
+
+static int wdog_set_heartbeat(int t)
+{
+ if (t < 1 || t > WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET))
+ return -EINVAL;
+
+ heartbeat = t;
+ wdog_ticks = SECS_TO_WDOG_TICKS(t);
+ return 0;
+}
+
+/**
+ * @file: file handle to the watchdog
+ * @buf: buffer to write (unused as data does not matter here
+ * @count: count of bytes
+ * @ppos: pointer to the position to write. No seeks allowed
+ *
+ * A write to a watchdog device is defined as a keepalive signal.
+ *
+ * if 'nowayout' is set then normally a close() is ignored. But
+ * if you write 'V' first then the close() will stop the timer.
+ */
+
+static ssize_t wdog_write(struct file *file, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ if (count) {
+ if (!nowayout) {
+ size_t i;
+
+ /* In case it was set long ago */
+ expect_close = 0;
+
+ for (i = 0; i != count; i++) {
+ char c;
+ if (get_user(c, buf + i))
+ return -EFAULT;
+ if (c == 'V')
+ expect_close = 42;
+ }
+ }
+ wdog_ping();
+ }
+ return count;
+}
+
+static int wdog_get_status(void)
+{
+ unsigned long flags;
+ int status = 0;
+ spin_lock_irqsave(&wdog_lock, flags);
+ /* FIXME: readback reset reason */
+ spin_unlock_irqrestore(&wdog_lock, flags);
+ return status;
+}
+
+static uint32_t wdog_get_remaining(void)
+{
+ uint32_t ret = ioread32(__io_address(PM_WDOG));
+ return ret & PM_WDOG_TIME_SET;
+}
+
+/**
+ * @file: file handle to the device
+ * @cmd: watchdog command
+ * @arg: argument pointer
+ *
+ * The watchdog API defines a common set of functions for all watchdogs
+ * according to their available features. We only actually usefully support
+ * querying capabilities and current status.
+ */
+
+static long wdog_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+ void __user *argp = (void __user *)arg;
+ int __user *p = argp;
+ int new_heartbeat;
+ int status;
+ int options;
+ uint32_t remaining;
+
+ struct watchdog_info ident = {
+ .options = WDIOF_SETTIMEOUT|
+ WDIOF_MAGICCLOSE|
+ WDIOF_KEEPALIVEPING,
+ .firmware_version = 1,
+ .identity = "BCM2708",
+ };
+
+ switch (cmd) {
+ case WDIOC_GETSUPPORT:
+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+ case WDIOC_GETSTATUS:
+ status = wdog_get_status();
+ return put_user(status, p);
+ case WDIOC_GETBOOTSTATUS:
+ return put_user(0, p);
+ case WDIOC_KEEPALIVE:
+ wdog_ping();
+ return 0;
+ case WDIOC_SETTIMEOUT:
+ if (get_user(new_heartbeat, p))
+ return -EFAULT;
+ if (wdog_set_heartbeat(new_heartbeat))
+ return -EINVAL;
+ wdog_ping();
+ /* Fall */
+ case WDIOC_GETTIMEOUT:
+ return put_user(heartbeat, p);
+ case WDIOC_GETTIMELEFT:
+ remaining = WDOG_TICKS_TO_SECS(wdog_get_remaining());
+ return put_user(remaining, p);
+ case WDIOC_SETOPTIONS:
+ if (get_user(options, p))
+ return -EFAULT;
+ if (options & WDIOS_DISABLECARD)
+ wdog_stop();
+ if (options & WDIOS_ENABLECARD)
+ wdog_start(wdog_ticks);
+ return 0;
+ default:
+ return -ENOTTY;
+ }
+}
+
+/**
+ * @inode: inode of device
+ * @file: file handle to device
+ *
+ * The watchdog device has been opened. The watchdog device is single
+ * open and on opening we load the counters.
+ */
+
+static int wdog_open(struct inode *inode, struct file *file)
+{
+ if (test_and_set_bit(0, &wdog_is_open))
+ return -EBUSY;
+ /*
+ * Activate
+ */
+ wdog_start(wdog_ticks);
+ return nonseekable_open(inode, file);
+}
+
+/**
+ * @inode: inode to board
+ * @file: file handle to board
+ *
+ * The watchdog has a configurable API. There is a religious dispute
+ * between people who want their watchdog to be able to shut down and
+ * those who want to be sure if the watchdog manager dies the machine
+ * reboots. In the former case we disable the counters, in the latter
+ * case you have to open it again very soon.
+ */
+
+static int wdog_release(struct inode *inode, struct file *file)
+{
+ if (expect_close == 42) {
+ wdog_stop();
+ } else {
+ printk(KERN_CRIT
+ "wdt: WDT device closed unexpectedly. WDT will not stop!\n");
+ wdog_ping();
+ }
+ clear_bit(0, &wdog_is_open);
+ expect_close = 0;
+ return 0;
+}
+
+/**
+ * @this: our notifier block
+ * @code: the event being reported
+ * @unused: unused
+ *
+ * Our notifier is called on system shutdowns. Turn the watchdog
+ * off so that it does not fire during the next reboot.
+ */
+
+static int wdog_notify_sys(struct notifier_block *this, unsigned long code,
+ void *unused)
+{
+ if (code == SYS_DOWN || code == SYS_HALT)
+ wdog_stop();
+ return NOTIFY_DONE;
+}
+
+/*
+ * Kernel Interfaces
+ */
+
+
+static const struct file_operations wdog_fops = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .write = wdog_write,
+ .unlocked_ioctl = wdog_ioctl,
+ .open = wdog_open,
+ .release = wdog_release,
+};
+
+static struct miscdevice wdog_miscdev = {
+ .minor = WATCHDOG_MINOR,
+ .name = "watchdog",
+ .fops = &wdog_fops,
+};
+
+/*
+ * The WDT card needs to learn about soft shutdowns in order to
+ * turn the timebomb registers off.
+ */
+
+static struct notifier_block wdog_notifier = {
+ .notifier_call = wdog_notify_sys,
+};
+
+/**
+ * cleanup_module:
+ *
+ * Unload the watchdog. You cannot do this with any file handles open.
+ * If your watchdog is set to continue ticking on close and you unload
+ * it, well it keeps ticking. We won't get the interrupt but the board
+ * will not touch PC memory so all is fine. You just have to load a new
+ * module in 60 seconds or reboot.
+ */
+
+static void __exit wdog_exit(void)
+{
+ misc_deregister(&wdog_miscdev);
+ unregister_reboot_notifier(&wdog_notifier);
+}
+
+static int __init wdog_init(void)
+{
+ int ret;
+
+ /* Check that the heartbeat value is within it's range;
+ if not reset to the default */
+ if (wdog_set_heartbeat(heartbeat)) {
+ wdog_set_heartbeat(WD_TIMO);
+ printk(KERN_INFO "bcm2708_wdog: heartbeat value must be "
+ "0 < heartbeat < %d, using %d\n",
+ WDOG_TICKS_TO_SECS(PM_WDOG_TIME_SET),
+ WD_TIMO);
+ }
+
+ ret = register_reboot_notifier(&wdog_notifier);
+ if (ret) {
+ printk(KERN_ERR
+ "wdt: cannot register reboot notifier (err=%d)\n", ret);
+ goto out_reboot;
+ }
+
+ ret = misc_register(&wdog_miscdev);
+ if (ret) {
+ printk(KERN_ERR
+ "wdt: cannot register miscdev on minor=%d (err=%d)\n",
+ WATCHDOG_MINOR, ret);
+ goto out_misc;
+ }
+
+ printk(KERN_INFO "bcm2708 watchdog, heartbeat=%d sec (nowayout=%d)\n",
+ heartbeat, nowayout);
+ return 0;
+
+out_misc:
+ unregister_reboot_notifier(&wdog_notifier);
+out_reboot:
+ return ret;
+}
+
+module_init(wdog_init);
+module_exit(wdog_exit);
+
+MODULE_AUTHOR("Luke Diamand");
+MODULE_DESCRIPTION("Driver for BCM2708 watchdog");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
+MODULE_ALIAS_MISCDEV(TEMP_MINOR);
+MODULE_LICENSE("GPL");
+

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