Initial import

1 files changed, 476 insertions, 0 deletions

diff --git a/drivers/watchdog/bfin_wdt.c b/drivers/watchdog/bfin_wdt.c
new file mode 100644
index 000000000..aa4d2e8a8
--- /dev/null
+++ b/drivers/watchdog/bfin_wdt.c
@@ -0,0 +1,476 @@
+/*
+ * 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.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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/init.h>
+#include <linux/interrupt.h>
+#include <linux/uaccess.h>
+#include <asm/blackfin.h>
+#include <asm/bfin_watchdog.h>
+
+#define stamp(fmt, args...) \
+	pr_debug("%s:%i: " fmt "\n", __func__, __LINE__, ## args)
+#define stampit() stamp("here i am")
+
+#define WATCHDOG_NAME "bfin-wdt"
+
+/* 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
+
+/* some defaults */
+#define WATCHDOG_TIMEOUT 20
+
+static unsigned int timeout = WATCHDOG_TIMEOUT;
+static bool 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) {
+		pr_warn("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 {
+		pr_crit("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;
+	}
+}
+
+#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,
+};
+
+/**
+ *	bfin_wdt_probe - Initialize module
+ *
+ *	Registers the misc device.  Actual device
+ *	initialization is handled by bfin_wdt_open().
+ */
+static int bfin_wdt_probe(struct platform_device *pdev)
+{
+	int ret;
+
+	ret = misc_register(&bfin_wdt_miscdev);
+	if (ret) {
+		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
+		       WATCHDOG_MINOR, ret);
+		return ret;
+	}
+
+	pr_info("initialized: timeout=%d sec (nowayout=%d)\n",
+		timeout, nowayout);
+
+	return 0;
+}
+
+/**
+ *	bfin_wdt_remove - Initialize module
+ *
+ *	Unregisters the misc device.  Actual device
+ *	deinitialization is handled by bfin_wdt_close().
+ */
+static int bfin_wdt_remove(struct platform_device *pdev)
+{
+	misc_deregister(&bfin_wdt_miscdev);
+	return 0;
+}
+
+/**
+ *	bfin_wdt_shutdown - Soft Shutdown Handler
+ *
+ *	Handles the soft shutdown event.
+ */
+static void bfin_wdt_shutdown(struct platform_device *pdev)
+{
+	stampit();
+
+	bfin_wdt_stop();
+}
+
+static struct platform_device *bfin_wdt_device;
+
+static struct platform_driver bfin_wdt_driver = {
+	.probe     = bfin_wdt_probe,
+	.remove    = bfin_wdt_remove,
+	.shutdown  = bfin_wdt_shutdown,
+	.suspend   = bfin_wdt_suspend,
+	.resume    = bfin_wdt_resume,
+	.driver    = {
+		.name  = WATCHDOG_NAME,
+	},
+};
+
+/**
+ *	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_err("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_err("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_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, bool, 0);
+MODULE_PARM_DESC(nowayout,
+	"Watchdog cannot be stopped once started (default="
+		__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");