cpwatchdog: Move to drivers/watchdog/cpwd.c

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 695 insertions, 0 deletions

diff --git a/drivers/watchdog/cpwd.c b/drivers/watchdog/cpwd.c
new file mode 100644
index 0000000..1f1ee25
--- /dev/null
+++ b/drivers/watchdog/cpwd.c
@@ -0,0 +1,695 @@
+/* cpwd.c - driver implementation for hardware watchdog
+ * timers found on Sun Microsystems CP1400 and CP1500 boards.
+ *
+ * This device supports both the generic Linux watchdog 
+ * interface and Solaris-compatible ioctls as best it is
+ * able.
+ *
+ * NOTE: 	CP1400 systems appear to have a defective intr_mask
+ * 			register on the PLD, preventing the disabling of
+ * 			timer interrupts.  We use a timer to periodically 
+ * 			reset 'stopped' watchdogs on affected platforms.
+ *
+ * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
+ * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/major.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/timer.h>
+#include <linux/smp_lock.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+
+#include <asm/irq.h>
+#include <asm/uaccess.h>
+
+#include <asm/watchdog.h>
+
+#define DRIVER_NAME	"cpwd"
+#define PFX		DRIVER_NAME ": "
+
+#define WD_OBPNAME	"watchdog"
+#define WD_BADMODEL	"SUNW,501-5336"
+#define WD_BTIMEOUT	(jiffies + (HZ * 1000))
+#define WD_BLIMIT	0xFFFF
+
+#define WD0_MINOR	212
+#define WD1_MINOR	213	
+#define WD2_MINOR	214	
+
+/* Internal driver definitions.  */
+#define WD0_ID			0
+#define WD1_ID			1
+#define WD2_ID			2
+#define WD_NUMDEVS		3
+
+#define WD_INTR_OFF		0
+#define WD_INTR_ON		1
+
+#define WD_STAT_INIT	0x01	/* Watchdog timer is initialized	*/
+#define WD_STAT_BSTOP	0x02	/* Watchdog timer is brokenstopped	*/
+#define WD_STAT_SVCD	0x04	/* Watchdog interrupt occurred		*/
+
+/* Register value definitions
+ */
+#define WD0_INTR_MASK	0x01	/* Watchdog device interrupt masks	*/
+#define WD1_INTR_MASK	0x02
+#define WD2_INTR_MASK	0x04
+
+#define WD_S_RUNNING	0x01	/* Watchdog device status running	*/
+#define WD_S_EXPIRED	0x02	/* Watchdog device status expired	*/
+
+struct cpwd {
+	void __iomem	*regs;
+	spinlock_t	lock;
+
+	unsigned int	irq;
+
+	unsigned long	timeout;
+	bool		enabled;
+	bool		reboot;
+	bool		broken;
+	bool		initialized;
+
+	struct {
+		struct miscdevice	misc;
+		void __iomem		*regs;
+		u8			intr_mask;
+		u8			runstatus;
+		u16			timeout;
+	} devs[WD_NUMDEVS];
+};
+
+static struct cpwd *cpwd_device;
+
+/* Sun uses Altera PLD EPF8820ATC144-4 
+ * providing three hardware watchdogs:
+ *
+ * 	1) RIC - sends an interrupt when triggered
+ * 	2) XIR - asserts XIR_B_RESET when triggered, resets CPU
+ * 	3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
+ *
+ *** Timer register block definition (struct wd_timer_regblk)
+ *
+ * dcntr and limit registers (halfword access):      
+ * -------------------
+ * | 15 | ...| 1 | 0 |
+ * -------------------
+ * |-  counter val  -|
+ * -------------------
+ * dcntr - 	Current 16-bit downcounter value.
+ * 			When downcounter reaches '0' watchdog expires.
+ * 			Reading this register resets downcounter with 'limit' value.
+ * limit - 	16-bit countdown value in 1/10th second increments.
+ * 			Writing this register begins countdown with input value.
+ * 			Reading from this register does not affect counter.
+ * NOTES:	After watchdog reset, dcntr and limit contain '1'
+ *
+ * status register (byte access):
+ * ---------------------------
+ * | 7 | ... | 2 |  1  |  0  |
+ * --------------+------------
+ * |-   UNUSED  -| EXP | RUN |
+ * ---------------------------
+ * status-	Bit 0 - Watchdog is running
+ * 			Bit 1 - Watchdog has expired
+ *
+ *** PLD register block definition (struct wd_pld_regblk)
+ *
+ * intr_mask register (byte access):
+ * ---------------------------------
+ * | 7 | ... | 3 |  2  |  1  |  0  |
+ * +-------------+------------------
+ * |-   UNUSED  -| WD3 | WD2 | WD1 |
+ * ---------------------------------
+ * WD3 -  1 == Interrupt disabled for watchdog 3
+ * WD2 -  1 == Interrupt disabled for watchdog 2
+ * WD1 -  1 == Interrupt disabled for watchdog 1
+ *
+ * pld_status register (byte access):
+ * UNKNOWN, MAGICAL MYSTERY REGISTER
+ *
+ */
+#define WD_TIMER_REGSZ	16
+#define WD0_OFF		0
+#define WD1_OFF		(WD_TIMER_REGSZ * 1)
+#define WD2_OFF		(WD_TIMER_REGSZ * 2)
+#define PLD_OFF		(WD_TIMER_REGSZ * 3)
+
+#define WD_DCNTR	0x00
+#define WD_LIMIT	0x04
+#define WD_STATUS	0x08
+
+#define PLD_IMASK	(PLD_OFF + 0x00)
+#define PLD_STATUS	(PLD_OFF + 0x04)
+
+static struct timer_list cpwd_timer;
+
+static int wd0_timeout = 0;
+static int wd1_timeout = 0;
+static int wd2_timeout = 0;
+
+module_param	(wd0_timeout, int, 0);
+MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
+module_param 	(wd1_timeout, int, 0);
+MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
+module_param 	(wd2_timeout, int, 0);
+MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
+
+MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
+MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
+MODULE_LICENSE("GPL");
+MODULE_SUPPORTED_DEVICE("watchdog");
+
+static void cpwd_writew(u16 val, void __iomem *addr)
+{
+	writew(cpu_to_le16(val), addr);
+}
+static u16 cpwd_readw(void __iomem *addr)
+{
+	u16 val = readw(addr);
+
+	return le16_to_cpu(val);
+}
+
+static void cpwd_writeb(u8 val, void __iomem *addr)
+{
+	writeb(val, addr);
+}
+
+static u8 cpwd_readb(void __iomem *addr)
+{
+	return readb(addr);
+}
+
+/* Enable or disable watchdog interrupts
+ * Because of the CP1400 defect this should only be
+ * called during initialzation or by wd_[start|stop]timer()
+ *
+ * index 	- sub-device index, or -1 for 'all'
+ * enable	- non-zero to enable interrupts, zero to disable
+ */
+static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
+{
+	unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
+	unsigned char setregs = 
+		(index == -1) ? 
+		(WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) : 
+		(p->devs[index].intr_mask);
+
+	if (enable == WD_INTR_ON)
+		curregs &= ~setregs;
+	else
+		curregs |= setregs;
+
+	cpwd_writeb(curregs, p->regs + PLD_IMASK);
+}
+
+/* Restarts timer with maximum limit value and
+ * does not unset 'brokenstop' value.
+ */
+static void cpwd_resetbrokentimer(struct cpwd *p, int index)
+{
+	cpwd_toggleintr(p, index, WD_INTR_ON);
+	cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
+}
+
+/* Timer method called to reset stopped watchdogs--
+ * because of the PLD bug on CP1400, we cannot mask
+ * interrupts within the PLD so me must continually
+ * reset the timers ad infinitum.
+ */
+static void cpwd_brokentimer(unsigned long data)
+{
+	struct cpwd *p = (struct cpwd *) data;
+	int id, tripped = 0;
+
+	/* kill a running timer instance, in case we
+	 * were called directly instead of by kernel timer
+	 */
+	if (timer_pending(&cpwd_timer))
+		del_timer(&cpwd_timer);
+
+	for (id = 0; id < WD_NUMDEVS; id++) {
+		if (p->devs[id].runstatus & WD_STAT_BSTOP) {
+			++tripped;
+			cpwd_resetbrokentimer(p, id);
+		}
+	}
+
+	if (tripped) {
+		/* there is at least one timer brokenstopped-- reschedule */
+		cpwd_timer.expires = WD_BTIMEOUT;
+		add_timer(&cpwd_timer);
+	}
+}
+
+/* Reset countdown timer with 'limit' value and continue countdown.
+ * This will not start a stopped timer.
+ */
+static void cpwd_pingtimer(struct cpwd *p, int index)
+{
+	if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
+		cpwd_readw(p->devs[index].regs + WD_DCNTR);
+}
+
+/* Stop a running watchdog timer-- the timer actually keeps
+ * running, but the interrupt is masked so that no action is
+ * taken upon expiration.
+ */
+static void cpwd_stoptimer(struct cpwd *p, int index)
+{
+	if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
+		cpwd_toggleintr(p, index, WD_INTR_OFF);
+
+		if (p->broken) {
+			p->devs[index].runstatus |= WD_STAT_BSTOP;
+			cpwd_brokentimer((unsigned long) p);
+		}
+	}
+}
+
+/* Start a watchdog timer with the specified limit value
+ * If the watchdog is running, it will be restarted with
+ * the provided limit value.
+ *
+ * This function will enable interrupts on the specified
+ * watchdog.
+ */
+static void cpwd_starttimer(struct cpwd *p, int index)
+{
+	if (p->broken)
+		p->devs[index].runstatus &= ~WD_STAT_BSTOP;
+
+	p->devs[index].runstatus &= ~WD_STAT_SVCD;
+
+	cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
+	cpwd_toggleintr(p, index, WD_INTR_ON);
+}
+
+static int cpwd_getstatus(struct cpwd *p, int index)
+{
+	unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
+	unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
+	unsigned char ret  = WD_STOPPED;
+
+	/* determine STOPPED */
+	if (!stat) 
+		return ret;
+
+	/* determine EXPIRED vs FREERUN vs RUNNING */
+	else if (WD_S_EXPIRED & stat) {
+		ret = WD_EXPIRED;
+	} else if(WD_S_RUNNING & stat) {
+		if (intr & p->devs[index].intr_mask) {
+			ret = WD_FREERUN;
+		} else {
+			/* Fudge WD_EXPIRED status for defective CP1400--
+			 * IF timer is running 
+			 * 	AND brokenstop is set 
+			 * 	AND an interrupt has been serviced
+			 * we are WD_EXPIRED.
+			 *
+			 * IF timer is running 
+			 * 	AND brokenstop is set 
+			 * 	AND no interrupt has been serviced
+			 * we are WD_FREERUN.
+			 */
+			if (p->broken &&
+			    (p->devs[index].runstatus & WD_STAT_BSTOP)) {
+				if (p->devs[index].runstatus & WD_STAT_SVCD) {
+					ret = WD_EXPIRED;
+				} else {
+					/* we could as well pretend we are expired */
+					ret = WD_FREERUN;
+				}
+			} else {
+				ret = WD_RUNNING;
+			}
+		}
+	}
+
+	/* determine SERVICED */
+	if (p->devs[index].runstatus & WD_STAT_SVCD)
+		ret |= WD_SERVICED;
+
+	return(ret);
+}
+
+static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
+{
+	struct cpwd *p = dev_id;
+
+	/* Only WD0 will interrupt-- others are NMI and we won't
+	 * see them here....
+	 */
+	spin_lock_irq(&p->lock);
+
+	cpwd_stoptimer(p, WD0_ID);
+	p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
+
+	spin_unlock_irq(&p->lock);
+
+	return IRQ_HANDLED;
+}
+
+static int cpwd_open(struct inode *inode, struct file *f)
+{
+	struct cpwd *p = cpwd_device;
+
+	lock_kernel();
+	switch(iminor(inode)) {
+		case WD0_MINOR:
+		case WD1_MINOR:
+		case WD2_MINOR:
+			break;
+
+		default:
+			unlock_kernel();
+			return -ENODEV;
+	}
+
+	/* Register IRQ on first open of device */
+	if (!p->initialized) {
+		if (request_irq(p->irq, &cpwd_interrupt, 
+				IRQF_SHARED, DRIVER_NAME, p)) {
+			printk(KERN_ERR PFX "Cannot register IRQ %d\n", 
+				p->irq);
+			unlock_kernel();
+			return -EBUSY;
+		}
+		p->initialized = true;
+	}
+
+	unlock_kernel();
+
+	return nonseekable_open(inode, f);
+}
+
+static int cpwd_release(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static int cpwd_ioctl(struct inode *inode, struct file *file, 
+		      unsigned int cmd, unsigned long arg)
+{
+	static struct watchdog_info info = {
+		.options		= WDIOF_SETTIMEOUT,
+		.firmware_version	= 1,
+		.identity		= DRIVER_NAME,
+	};
+	void __user *argp = (void __user *)arg;
+	int index = iminor(inode) - WD0_MINOR;
+	struct cpwd *p = cpwd_device;
+	int setopt = 0;
+
+	switch (cmd) {
+	/* Generic Linux IOCTLs */
+	case WDIOC_GETSUPPORT:
+		if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
+			return -EFAULT;
+		break;
+
+	case WDIOC_GETSTATUS:
+	case WDIOC_GETBOOTSTATUS:
+		if (put_user(0, (int __user *)argp))
+			return -EFAULT;
+		break;
+
+	case WDIOC_KEEPALIVE:
+		cpwd_pingtimer(p, index);
+		break;
+
+	case WDIOC_SETOPTIONS:
+		if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
+			return -EFAULT;
+
+		if (setopt & WDIOS_DISABLECARD) {
+			if (p->enabled)
+				return -EINVAL;
+			cpwd_stoptimer(p, index);
+		} else if (setopt & WDIOS_ENABLECARD) {
+			cpwd_starttimer(p, index);
+		} else {
+			return -EINVAL;
+		}	
+		break;
+
+	/* Solaris-compatible IOCTLs */
+	case WIOCGSTAT:
+		setopt = cpwd_getstatus(p, index);
+		if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
+			return -EFAULT;
+		break;
+
+	case WIOCSTART:
+		cpwd_starttimer(p, index);
+		break;
+
+	case WIOCSTOP:
+		if (p->enabled)
+			return(-EINVAL);
+
+		cpwd_stoptimer(p, index);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
+			      unsigned long arg)
+{
+	int rval = -ENOIOCTLCMD;
+
+	switch (cmd) {
+	/* solaris ioctls are specific to this driver */
+	case WIOCSTART:
+	case WIOCSTOP:
+	case WIOCGSTAT:
+		lock_kernel();
+		rval = cpwd_ioctl(file->f_path.dentry->d_inode, file, cmd, arg);
+		unlock_kernel();
+		break;
+
+	/* everything else is handled by the generic compat layer */
+	default:
+		break;
+	}
+
+	return rval;
+}
+
+static ssize_t cpwd_write(struct file *file, const char __user *buf, 
+			  size_t count, loff_t *ppos)
+{
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct cpwd *p = cpwd_device;
+	int index = iminor(inode);
+
+	if (count) {
+		cpwd_pingtimer(p, index);
+		return 1;
+	}
+
+	return 0;
+}
+
+static ssize_t cpwd_read(struct file * file, char __user *buffer,
+			 size_t count, loff_t *ppos)
+{
+	return -EINVAL;
+}
+
+static const struct file_operations cpwd_fops = {
+	.owner =	THIS_MODULE,
+	.ioctl =	cpwd_ioctl,
+	.compat_ioctl =	cpwd_compat_ioctl,
+	.open =		cpwd_open,
+	.write =	cpwd_write,
+	.read =		cpwd_read,
+	.release =	cpwd_release,
+};
+
+static int __devinit cpwd_probe(struct of_device *op,
+				const struct of_device_id *match)
+{
+	struct device_node *options;
+	const char *str_prop;
+	const void *prop_val;
+	int i, err = -EINVAL;
+	struct cpwd *p;
+
+	if (cpwd_device)
+		return -EINVAL;
+
+	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	err = -ENOMEM;
+	if (!p) {
+		printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
+		goto out;
+	}
+
+	p->irq = op->irqs[0];
+
+	spin_lock_init(&p->lock);
+
+	p->regs = of_ioremap(&op->resource[0], 0,
+			     4 * WD_TIMER_REGSZ, DRIVER_NAME);
+	if (!p->regs) {
+		printk(KERN_ERR PFX "Unable to map registers.\n");
+		goto out_free;
+	}
+
+	options = of_find_node_by_path("/options");
+	err = -ENODEV;
+	if (!options) {
+		printk(KERN_ERR PFX "Unable to find /options node.\n");
+		goto out_iounmap;
+	}
+
+	prop_val = of_get_property(options, "watchdog-enable?", NULL);
+	p->enabled = (prop_val ? true : false);
+
+	prop_val = of_get_property(options, "watchdog-reboot?", NULL);
+	p->reboot = (prop_val ? true : false);
+
+	str_prop = of_get_property(options, "watchdog-timeout", NULL);
+	if (str_prop)
+		p->timeout = simple_strtoul(str_prop, NULL, 10);
+
+	/* CP1400s seem to have broken PLD implementations-- the
+	 * interrupt_mask register cannot be written, so no timer
+	 * interrupts can be masked within the PLD.
+	 */
+	str_prop = of_get_property(op->node, "model", NULL);
+	p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
+
+	if (!p->enabled)
+		cpwd_toggleintr(p, -1, WD_INTR_OFF);
+
+	for (i = 0; i < WD_NUMDEVS; i++) {
+		static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
+		static int *parms[] = { &wd0_timeout,
+					&wd1_timeout,
+					&wd2_timeout };
+		struct miscdevice *mp = &p->devs[i].misc;
+
+		mp->minor = WD0_MINOR + i;
+		mp->name = cpwd_names[i];
+		mp->fops = &cpwd_fops;
+
+		p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
+		p->devs[i].intr_mask = (WD0_INTR_MASK << i);
+		p->devs[i].runstatus &= ~WD_STAT_BSTOP;
+		p->devs[i].runstatus |= WD_STAT_INIT;
+		p->devs[i].timeout = p->timeout;
+		if (*parms[i])
+			p->devs[i].timeout = *parms[i];
+
+		err = misc_register(&p->devs[i].misc);
+		if (err) {
+			printk(KERN_ERR "Could not register misc device for "
+			       "dev %d\n", i);
+			goto out_unregister;
+		}
+	}
+
+	if (p->broken) {
+		init_timer(&cpwd_timer);
+		cpwd_timer.function 	= cpwd_brokentimer;
+		cpwd_timer.data		= (unsigned long) p;
+		cpwd_timer.expires	= WD_BTIMEOUT;
+
+		printk(KERN_INFO PFX "PLD defect workaround enabled for "
+		       "model " WD_BADMODEL ".\n");
+	}
+
+	dev_set_drvdata(&op->dev, p);
+	cpwd_device = p;
+	err = 0;
+
+out:
+	return err;
+
+out_unregister:
+	for (i--; i >= 0; i--)
+		misc_deregister(&p->devs[i].misc);
+
+out_iounmap:
+	of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
+
+out_free:
+	kfree(p);
+	goto out;
+}
+
+static int __devexit cpwd_remove(struct of_device *op)
+{
+	struct cpwd *p = dev_get_drvdata(&op->dev);
+	int i;
+
+	for (i = 0; i < 4; i++) {
+		misc_deregister(&p->devs[i].misc);
+
+		if (!p->enabled) {
+			cpwd_stoptimer(p, i);
+			if (p->devs[i].runstatus & WD_STAT_BSTOP)
+				cpwd_resetbrokentimer(p, i);
+		}
+	}
+
+	if (p->broken)
+		del_timer_sync(&cpwd_timer);
+
+	if (p->initialized)
+		free_irq(p->irq, p);
+
+	of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
+	kfree(p);
+
+	cpwd_device = NULL;
+
+	return 0;
+}
+
+static struct of_device_id cpwd_match[] = {
+	{
+		.name = "watchdog",
+	},
+	{},
+};
+MODULE_DEVICE_TABLE(of, cpwd_match);
+
+static struct of_platform_driver cpwd_driver = {
+	.name		= DRIVER_NAME,
+	.match_table	= cpwd_match,
+	.probe		= cpwd_probe,
+	.remove		= __devexit_p(cpwd_remove),
+};
+
+static int __init cpwd_init(void)
+{
+	return of_register_driver(&cpwd_driver, &of_bus_type);
+}
+
+static void __exit cpwd_exit(void)
+{
+	of_unregister_driver(&cpwd_driver);
+}
+
+module_init(cpwd_init);
+module_exit(cpwd_exit);