Merge commit 'gcl/next' into next

1 files changed, 415 insertions, 13 deletions

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
index 4d76b7f2336c..17ecdf4c87ae 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_gpt.c
@@ -16,8 +16,14 @@
  * output signals or measure input signals.
  *
  * This driver supports the GPIO and IRQ controller functions of the GPT
- * device.  Timer functions are not yet supported, nor is the watchdog
- * timer.
+ * device.  Timer functions are not yet supported.
+ *
+ * The timer gpt0 can be used as watchdog (wdt).  If the wdt mode is used,
+ * this prevents the use of any gpt0 gpt function (i.e. they will fail with
+ * -EBUSY).  Thus, the safety wdt function always has precedence over the gpt
+ * function.  If the kernel has been compiled with CONFIG_WATCHDOG_NOWAYOUT,
+ * this means that gpt0 is locked in wdt mode until the next reboot - this
+ * may be a requirement in safety applications.
  *
  * To use the GPIO function, the following two properties must be added
  * to the device tree node for the gpt device (typically in the .dts file
@@ -46,17 +52,24 @@
  * the output mode.  This driver does not change the output mode setting.
  */
 
+#include <linux/device.h>
 #include <linux/irq.h>
 #include <linux/interrupt.h>
 #include <linux/io.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/of_gpio.h>
 #include <linux/kernel.h>
+#include <linux/watchdog.h>
+#include <linux/miscdevice.h>
+#include <linux/uaccess.h>
+#include <asm/div64.h>
 #include <asm/mpc52xx.h>
 
 MODULE_DESCRIPTION("Freescale MPC52xx gpt driver");
-MODULE_AUTHOR("Sascha Hauer, Grant Likely");
+MODULE_AUTHOR("Sascha Hauer, Grant Likely, Albrecht Dreß");
 MODULE_LICENSE("GPL");
 
 /**
@@ -66,18 +79,27 @@ MODULE_LICENSE("GPL");
  * @lock: spinlock to coordinate between different functions.
  * @of_gc: of_gpio_chip instance structure; used when GPIO is enabled
  * @irqhost: Pointer to irq_host instance; used when IRQ mode is supported
+ * @wdt_mode: only relevant for gpt0: bit 0 (MPC52xx_GPT_CAN_WDT) indicates
+ *   if the gpt may be used as wdt, bit 1 (MPC52xx_GPT_IS_WDT) indicates
+ *   if the timer is actively used as wdt which blocks gpt functions
  */
 struct mpc52xx_gpt_priv {
+	struct list_head list;		/* List of all GPT devices */
 	struct device *dev;
 	struct mpc52xx_gpt __iomem *regs;
 	spinlock_t lock;
 	struct irq_host *irqhost;
+	u32 ipb_freq;
+	u8 wdt_mode;
 
 #if defined(CONFIG_GPIOLIB)
 	struct of_gpio_chip of_gc;
 #endif
 };
 
+LIST_HEAD(mpc52xx_gpt_list);
+DEFINE_MUTEX(mpc52xx_gpt_list_mutex);
+
 #define MPC52xx_GPT_MODE_MS_MASK	(0x07)
 #define MPC52xx_GPT_MODE_MS_IC		(0x01)
 #define MPC52xx_GPT_MODE_MS_OC		(0x02)
@@ -88,15 +110,25 @@ struct mpc52xx_gpt_priv {
 #define MPC52xx_GPT_MODE_GPIO_OUT_LOW	(0x20)
 #define MPC52xx_GPT_MODE_GPIO_OUT_HIGH	(0x30)
 
+#define MPC52xx_GPT_MODE_COUNTER_ENABLE	(0x1000)
+#define MPC52xx_GPT_MODE_CONTINUOUS	(0x0400)
+#define MPC52xx_GPT_MODE_OPEN_DRAIN	(0x0200)
 #define MPC52xx_GPT_MODE_IRQ_EN		(0x0100)
+#define MPC52xx_GPT_MODE_WDT_EN		(0x8000)
 
 #define MPC52xx_GPT_MODE_ICT_MASK	(0x030000)
 #define MPC52xx_GPT_MODE_ICT_RISING	(0x010000)
 #define MPC52xx_GPT_MODE_ICT_FALLING	(0x020000)
 #define MPC52xx_GPT_MODE_ICT_TOGGLE	(0x030000)
 
+#define MPC52xx_GPT_MODE_WDT_PING	(0xa5)
+
 #define MPC52xx_GPT_STATUS_IRQMASK	(0x000f)
 
+#define MPC52xx_GPT_CAN_WDT		(1 << 0)
+#define MPC52xx_GPT_IS_WDT		(1 << 1)
+
+
 /* ---------------------------------------------------------------------
  * Cascaded interrupt controller hooks
  */
@@ -190,7 +222,7 @@ static int mpc52xx_gpt_irq_xlate(struct irq_host *h, struct device_node *ct,
 
 	dev_dbg(gpt->dev, "%s: flags=%i\n", __func__, intspec[0]);
 
-	if ((intsize < 1) || (intspec[0] < 1) || (intspec[0] > 3)) {
+	if ((intsize < 1) || (intspec[0] > 3)) {
 		dev_err(gpt->dev, "bad irq specifier in %s\n", ct->full_name);
 		return -EINVAL;
 	}
@@ -211,13 +243,11 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
 {
 	int cascade_virq;
 	unsigned long flags;
-
-	/* Only setup cascaded IRQ if device tree claims the GPT is
-	 * an interrupt controller */
-	if (!of_find_property(node, "interrupt-controller", NULL))
-		return;
+	u32 mode;
 
 	cascade_virq = irq_of_parse_and_map(node, 0);
+	if (!cascade_virq)
+		return;
 
 	gpt->irqhost = irq_alloc_host(node, IRQ_HOST_MAP_LINEAR, 1,
 				      &mpc52xx_gpt_irq_ops, -1);
@@ -227,14 +257,16 @@ mpc52xx_gpt_irq_setup(struct mpc52xx_gpt_priv *gpt, struct device_node *node)
 	}
 
 	gpt->irqhost->host_data = gpt;
-
 	set_irq_data(cascade_virq, gpt);
 	set_irq_chained_handler(cascade_virq, mpc52xx_gpt_irq_cascade);
 
-	/* Set to Input Capture mode */
+	/* If the GPT is currently disabled, then change it to be in Input
+	 * Capture mode.  If the mode is non-zero, then the pin could be
+	 * already in use for something. */
 	spin_lock_irqsave(&gpt->lock, flags);
-	clrsetbits_be32(&gpt->regs->mode, MPC52xx_GPT_MODE_MS_MASK,
-			MPC52xx_GPT_MODE_MS_IC);
+	mode = in_be32(&gpt->regs->mode);
+	if ((mode & MPC52xx_GPT_MODE_MS_MASK) == 0)
+		out_be32(&gpt->regs->mode, mode | MPC52xx_GPT_MODE_MS_IC);
 	spin_unlock_irqrestore(&gpt->lock, flags);
 
 	dev_dbg(gpt->dev, "%s() complete. virq=%i\n", __func__, cascade_virq);
@@ -335,6 +367,354 @@ static void
 mpc52xx_gpt_gpio_setup(struct mpc52xx_gpt_priv *p, struct device_node *np) { }
 #endif /* defined(CONFIG_GPIOLIB) */
 
+/***********************************************************************
+ * Timer API
+ */
+
+/**
+ * mpc52xx_gpt_from_irq - Return the GPT device associated with an IRQ number
+ * @irq: irq of timer.
+ */
+struct mpc52xx_gpt_priv *mpc52xx_gpt_from_irq(int irq)
+{
+	struct mpc52xx_gpt_priv *gpt;
+	struct list_head *pos;
+
+	/* Iterate over the list of timers looking for a matching device */
+	mutex_lock(&mpc52xx_gpt_list_mutex);
+	list_for_each(pos, &mpc52xx_gpt_list) {
+		gpt = container_of(pos, struct mpc52xx_gpt_priv, list);
+		if (gpt->irqhost && irq == irq_linear_revmap(gpt->irqhost, 0)) {
+			mutex_unlock(&mpc52xx_gpt_list_mutex);
+			return gpt;
+		}
+	}
+	mutex_unlock(&mpc52xx_gpt_list_mutex);
+
+	return NULL;
+}
+EXPORT_SYMBOL(mpc52xx_gpt_from_irq);
+
+static int mpc52xx_gpt_do_start(struct mpc52xx_gpt_priv *gpt, u64 period,
+				int continuous, int as_wdt)
+{
+	u32 clear, set;
+	u64 clocks;
+	u32 prescale;
+	unsigned long flags;
+
+	clear = MPC52xx_GPT_MODE_MS_MASK | MPC52xx_GPT_MODE_CONTINUOUS;
+	set = MPC52xx_GPT_MODE_MS_GPIO | MPC52xx_GPT_MODE_COUNTER_ENABLE;
+	if (as_wdt) {
+		clear |= MPC52xx_GPT_MODE_IRQ_EN;
+		set |= MPC52xx_GPT_MODE_WDT_EN;
+	} else if (continuous)
+		set |= MPC52xx_GPT_MODE_CONTINUOUS;
+
+	/* Determine the number of clocks in the requested period.  64 bit
+	 * arithmatic is done here to preserve the precision until the value
+	 * is scaled back down into the u32 range.  Period is in 'ns', bus
+	 * frequency is in Hz. */
+	clocks = period * (u64)gpt->ipb_freq;
+	do_div(clocks, 1000000000); /* Scale it down to ns range */
+
+	/* This device cannot handle a clock count greater than 32 bits */
+	if (clocks > 0xffffffff)
+		return -EINVAL;
+
+	/* Calculate the prescaler and count values from the clocks value.
+	 * 'clocks' is the number of clock ticks in the period.  The timer
+	 * has 16 bit precision and a 16 bit prescaler.  Prescaler is
+	 * calculated by integer dividing the clocks by 0x10000 (shifting
+	 * down 16 bits) to obtain the smallest possible divisor for clocks
+	 * to get a 16 bit count value.
+	 *
+	 * Note: the prescale register is '1' based, not '0' based.  ie. a
+	 * value of '1' means divide the clock by one.  0xffff divides the
+	 * clock by 0xffff.  '0x0000' does not divide by zero, but wraps
+	 * around and divides by 0x10000.  That is why prescale must be
+	 * a u32 variable, not a u16, for this calculation. */
+	prescale = (clocks >> 16) + 1;
+	do_div(clocks, prescale);
+	if (clocks > 0xffff) {
+		pr_err("calculation error; prescale:%x clocks:%llx\n",
+		       prescale, clocks);
+		return -EINVAL;
+	}
+
+	/* Set and enable the timer, reject an attempt to use a wdt as gpt */
+	spin_lock_irqsave(&gpt->lock, flags);
+	if (as_wdt)
+		gpt->wdt_mode |= MPC52xx_GPT_IS_WDT;
+	else if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) {
+		spin_unlock_irqrestore(&gpt->lock, flags);
+		return -EBUSY;
+	}
+	out_be32(&gpt->regs->count, prescale << 16 | clocks);
+	clrsetbits_be32(&gpt->regs->mode, clear, set);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	return 0;
+}
+
+/**
+ * mpc52xx_gpt_start_timer - Set and enable the GPT timer
+ * @gpt: Pointer to gpt private data structure
+ * @period: period of timer in ns; max. ~130s @ 33MHz IPB clock
+ * @continuous: set to 1 to make timer continuous free running
+ *
+ * An interrupt will be generated every time the timer fires
+ */
+int mpc52xx_gpt_start_timer(struct mpc52xx_gpt_priv *gpt, u64 period,
+                            int continuous)
+{
+	return mpc52xx_gpt_do_start(gpt, period, continuous, 0);
+}
+EXPORT_SYMBOL(mpc52xx_gpt_start_timer);
+
+/**
+ * mpc52xx_gpt_stop_timer - Stop a gpt
+ * @gpt: Pointer to gpt private data structure
+ *
+ * Returns an error if attempting to stop a wdt
+ */
+int mpc52xx_gpt_stop_timer(struct mpc52xx_gpt_priv *gpt)
+{
+	unsigned long flags;
+
+	/* reject the operation if the timer is used as watchdog (gpt 0 only) */
+	spin_lock_irqsave(&gpt->lock, flags);
+	if ((gpt->wdt_mode & MPC52xx_GPT_IS_WDT) != 0) {
+		spin_unlock_irqrestore(&gpt->lock, flags);
+		return -EBUSY;
+	}
+
+	clrbits32(&gpt->regs->mode, MPC52xx_GPT_MODE_COUNTER_ENABLE);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(mpc52xx_gpt_stop_timer);
+
+/**
+ * mpc52xx_gpt_timer_period - Read the timer period
+ * @gpt: Pointer to gpt private data structure
+ *
+ * Returns the timer period in ns
+ */
+u64 mpc52xx_gpt_timer_period(struct mpc52xx_gpt_priv *gpt)
+{
+	u64 period;
+	u64 prescale;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpt->lock, flags);
+	period = in_be32(&gpt->regs->count);
+	spin_unlock_irqrestore(&gpt->lock, flags);
+
+	prescale = period >> 16;
+	period &= 0xffff;
+	if (prescale == 0)
+		prescale = 0x10000;
+	period = period * prescale * 1000000000ULL;
+	do_div(period, (u64)gpt->ipb_freq);
+	return period;
+}
+EXPORT_SYMBOL(mpc52xx_gpt_timer_period);
+
+#if defined(CONFIG_MPC5200_WDT)
+/***********************************************************************
+ * Watchdog API for gpt0
+ */
+
+#define WDT_IDENTITY	    "mpc52xx watchdog on GPT0"
+
+/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
+static unsigned long wdt_is_active;
+
+/* wdt-capable gpt */
+static struct mpc52xx_gpt_priv *mpc52xx_gpt_wdt;
+
+/* low-level wdt functions */
+static inline void mpc52xx_gpt_wdt_ping(struct mpc52xx_gpt_priv *gpt_wdt)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpt_wdt->lock, flags);
+	out_8((u8 *) &gpt_wdt->regs->mode, MPC52xx_GPT_MODE_WDT_PING);
+	spin_unlock_irqrestore(&gpt_wdt->lock, flags);
+}
+
+/* wdt misc device api */
+static ssize_t mpc52xx_wdt_write(struct file *file, const char __user *data,
+				 size_t len, loff_t *ppos)
+{
+	struct mpc52xx_gpt_priv *gpt_wdt = file->private_data;
+	mpc52xx_gpt_wdt_ping(gpt_wdt);
+	return 0;
+}
+
+static struct watchdog_info mpc5200_wdt_info = {
+	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING,
+	.identity	= WDT_IDENTITY,
+};
+
+static long mpc52xx_wdt_ioctl(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	struct mpc52xx_gpt_priv *gpt_wdt = file->private_data;
+	int __user *data = (int __user *)arg;
+	int timeout;
+	u64 real_timeout;
+	int ret = 0;
+
+	switch (cmd) {
+	case WDIOC_GETSUPPORT:
+		ret = copy_to_user(data, &mpc5200_wdt_info,
+				   sizeof(mpc5200_wdt_info));
+		if (ret)
+			ret = -EFAULT;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		ret = put_user(0, data);
+		break;
+
+	case WDIOC_KEEPALIVE:
+		mpc52xx_gpt_wdt_ping(gpt_wdt);
+		break;
+
+	case WDIOC_SETTIMEOUT:
+		ret = get_user(timeout, data);
+		if (ret)
+			break;
+		real_timeout = (u64) timeout * 1000000000ULL;
+		ret = mpc52xx_gpt_do_start(gpt_wdt, real_timeout, 0, 1);
+		if (ret)
+			break;
+		/* fall through and return the timeout */
+
+	case WDIOC_GETTIMEOUT:
+		/* we need to round here as to avoid e.g. the following
+		 * situation:
+		 * - timeout requested is 1 second;
+		 * - real timeout @33MHz is 999997090ns
+		 * - the int divide by 10^9 will return 0.
+		 */
+		real_timeout =
+			mpc52xx_gpt_timer_period(gpt_wdt) + 500000000ULL;
+		do_div(real_timeout, 1000000000ULL);
+		timeout = (int) real_timeout;
+		ret = put_user(timeout, data);
+		break;
+
+	default:
+		ret = -ENOTTY;
+	}
+	return ret;
+}
+
+static int mpc52xx_wdt_open(struct inode *inode, struct file *file)
+{
+	int ret;
+
+	/* sanity check */
+	if (!mpc52xx_gpt_wdt)
+		return -ENODEV;
+
+	/* /dev/watchdog can only be opened once */
+	if (test_and_set_bit(0, &wdt_is_active))
+		return -EBUSY;
+
+	/* Set and activate the watchdog with 30 seconds timeout */
+	ret = mpc52xx_gpt_do_start(mpc52xx_gpt_wdt, 30ULL * 1000000000ULL,
+				   0, 1);
+	if (ret) {
+		clear_bit(0, &wdt_is_active);
+		return ret;
+	}
+
+	file->private_data = mpc52xx_gpt_wdt;
+	return nonseekable_open(inode, file);
+}
+
+static int mpc52xx_wdt_release(struct inode *inode, struct file *file)
+{
+	/* note: releasing the wdt in NOWAYOUT-mode does not stop it */
+#if !defined(CONFIG_WATCHDOG_NOWAYOUT)
+	struct mpc52xx_gpt_priv *gpt_wdt = file->private_data;
+	unsigned long flags;
+
+	spin_lock_irqsave(&gpt_wdt->lock, flags);
+	clrbits32(&gpt_wdt->regs->mode,
+		  MPC52xx_GPT_MODE_COUNTER_ENABLE | MPC52xx_GPT_MODE_WDT_EN);
+	gpt_wdt->wdt_mode &= ~MPC52xx_GPT_IS_WDT;
+	spin_unlock_irqrestore(&gpt_wdt->lock, flags);
+#endif
+	clear_bit(0, &wdt_is_active);
+	return 0;
+}
+
+
+static const struct file_operations mpc52xx_wdt_fops = {
+	.owner		= THIS_MODULE,
+	.llseek		= no_llseek,
+	.write		= mpc52xx_wdt_write,
+	.unlocked_ioctl = mpc52xx_wdt_ioctl,
+	.open		= mpc52xx_wdt_open,
+	.release	= mpc52xx_wdt_release,
+};
+
+static struct miscdevice mpc52xx_wdt_miscdev = {
+	.minor		= WATCHDOG_MINOR,
+	.name		= "watchdog",
+	.fops		= &mpc52xx_wdt_fops,
+};
+
+static int __devinit mpc52xx_gpt_wdt_init(void)
+{
+	int err;
+
+	/* try to register the watchdog misc device */
+	err = misc_register(&mpc52xx_wdt_miscdev);
+	if (err)
+		pr_err("%s: cannot register watchdog device\n", WDT_IDENTITY);
+	else
+		pr_info("%s: watchdog device registered\n", WDT_IDENTITY);
+	return err;
+}
+
+static int mpc52xx_gpt_wdt_setup(struct mpc52xx_gpt_priv *gpt,
+				 const u32 *period)
+{
+	u64 real_timeout;
+
+	/* remember the gpt for the wdt operation */
+	mpc52xx_gpt_wdt = gpt;
+
+	/* configure the wdt if the device tree contained a timeout */
+	if (!period || *period == 0)
+		return 0;
+
+	real_timeout = (u64) *period * 1000000000ULL;
+	if (mpc52xx_gpt_do_start(gpt, real_timeout, 0, 1))
+		dev_warn(gpt->dev, "starting as wdt failed\n");
+	else
+		dev_info(gpt->dev, "watchdog set to %us timeout\n", *period);
+	return 0;
+}
+
+#else
+
+static int __devinit mpc52xx_gpt_wdt_init(void)
+{
+	return 0;
+}
+
+#define mpc52xx_gpt_wdt_setup(x, y)		(0)
+
+#endif	/*  CONFIG_MPC5200_WDT	*/
+
 /* ---------------------------------------------------------------------
  * of_platform bus binding code
  */
@@ -349,6 +729,7 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
 
 	spin_lock_init(&gpt->lock);
 	gpt->dev = &ofdev->dev;
+	gpt->ipb_freq = mpc5xxx_get_bus_frequency(ofdev->node);
 	gpt->regs = of_iomap(ofdev->node, 0);
 	if (!gpt->regs) {
 		kfree(gpt);
@@ -360,6 +741,26 @@ static int __devinit mpc52xx_gpt_probe(struct of_device *ofdev,
 	mpc52xx_gpt_gpio_setup(gpt, ofdev->node);
 	mpc52xx_gpt_irq_setup(gpt, ofdev->node);
 
+	mutex_lock(&mpc52xx_gpt_list_mutex);
+	list_add(&gpt->list, &mpc52xx_gpt_list);
+	mutex_unlock(&mpc52xx_gpt_list_mutex);
+
+	/* check if this device could be a watchdog */
+	if (of_get_property(ofdev->node, "fsl,has-wdt", NULL) ||
+	    of_get_property(ofdev->node, "has-wdt", NULL)) {
+		const u32 *on_boot_wdt;
+
+		gpt->wdt_mode = MPC52xx_GPT_CAN_WDT;
+		on_boot_wdt = of_get_property(ofdev->node, "fsl,wdt-on-boot",
+					      NULL);
+		if (on_boot_wdt) {
+			dev_info(gpt->dev, "used as watchdog\n");
+			gpt->wdt_mode |= MPC52xx_GPT_IS_WDT;
+		} else
+			dev_info(gpt->dev, "can function as watchdog\n");
+		mpc52xx_gpt_wdt_setup(gpt, on_boot_wdt);
+	}
+
 	return 0;
 }
 
@@ -394,3 +795,4 @@ static int __init mpc52xx_gpt_init(void)
 
 /* Make sure GPIOs and IRQs get set up before anyone tries to use them */
 subsys_initcall(mpc52xx_gpt_init);
+device_initcall(mpc52xx_gpt_wdt_init);