Commit e9659e69 authored by Alejandro Cabrera's avatar Alejandro Cabrera Committed by Wim Van Sebroeck
Browse files

watchdog: Add Xilinx watchdog timer driver 



Watchdog timer device driver for Xilinx xps_timebase_wdt compatible ip cores.
It takes watchdog timer configuration from device tree and it needs that its
parent has defined the property "clock-frecuency".
It is compatible with watchdog timer kernel API, so user apps like watchdogd
may talk with it.

Signed-off-by: default avatarAlejandro Cabrera <aldaya@gmail.com>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 2fc5d52b

drivers/watchdog/Kconfig

+14 −0
Original line number Diff line number Diff line
@@ -888,6 +888,20 @@ config M54xx_WATCHDOG 
	  To compile this driver as a module, choose M here: the

	  module will be called m54xx_wdt.



# MicroBlaze Architecture



config XILINX_WATCHDOG

	tristate "Xilinx Watchdog timer"

	depends on MICROBLAZE

	---help---

	  Watchdog driver for the xps_timebase_wdt ip core.



	  IMPORTANT: The xps_timebase_wdt parent must have the property

	  "clock-frequency" at device tree.



	  To compile this driver as a module, choose M here: the

	  module will be called of_xilinx_wdt.



# MIPS Architecture



config ATH79_WDT

drivers/watchdog/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -110,6 +110,9 @@ obj-$(CONFIG_INTEL_SCU_WATCHDOG) += intel_scu_watchdog.o 
# M68K Architecture

obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o



# MicroBlaze Architecture

obj-$(CONFIG_XILINX_WATCHDOG) += of_xilinx_wdt.o



# MIPS Architecture

obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o

obj-$(CONFIG_BCM47XX_WDT) += bcm47xx_wdt.o

drivers/watchdog/of_xilinx_wdt.c

0 → 100644
+433 −0
Original line number Diff line number Diff line 
/*

*   of_xilinx_wdt.c  1.01  A Watchdog Device Driver for Xilinx xps_timebase_wdt

*

*   (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)

*

*       -----------------------

*

*   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.

*

*       -----------------------

*	30-May-2011 Alejandro Cabrera <aldaya@gmail.com>

*		- If "xlnx,wdt-enable-once" wasn't found on device tree the

*		  module will use CONFIG_WATCHDOG_NOWAYOUT

*		- If the device tree parameters ("clock-frequency" and

*		  "xlnx,wdt-interval") wasn't found the driver won't

*		  know the wdt reset interval

*/



#include <linux/module.h>

#include <linux/types.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/miscdevice.h>

#include <linux/init.h>

#include <linux/ioport.h>

#include <linux/watchdog.h>

#include <linux/io.h>

#include <linux/uaccess.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/of_address.h>



/* Register offsets for the Wdt device */

#define XWT_TWCSR0_OFFSET   0x0 /* Control/Status Register0 */

#define XWT_TWCSR1_OFFSET   0x4 /* Control/Status Register1 */

#define XWT_TBR_OFFSET      0x8 /* Timebase Register Offset */



/* Control/Status Register Masks  */

#define XWT_CSR0_WRS_MASK   0x00000008 /* Reset status */

#define XWT_CSR0_WDS_MASK   0x00000004 /* Timer state  */

#define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */



/* Control/Status Register 0/1 bits  */

#define XWT_CSRX_EWDT2_MASK 0x00000001 /* Enable bit 2 */



/* SelfTest constants */

#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000

#define XWT_TIMER_FAILED            0xFFFFFFFF



#define WATCHDOG_NAME     "Xilinx Watchdog"

#define PFX WATCHDOG_NAME ": "



struct xwdt_device {

	struct resource  res;

	void __iomem *base;

	u32 nowayout;

	u32 wdt_interval;

	u32 boot_status;

};



static struct xwdt_device xdev;



static  u32 timeout;

static  u32 control_status_reg;

static  u8  expect_close;

static  u8  no_timeout;

static unsigned long driver_open;



static  DEFINE_SPINLOCK(spinlock);



static void xwdt_start(void)

{

	spin_lock(&spinlock);



	/* Clean previous status and enable the watchdog timer */

	control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);

	control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);



	iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK),

				xdev.base + XWT_TWCSR0_OFFSET);



	iowrite32(XWT_CSRX_EWDT2_MASK, xdev.base + XWT_TWCSR1_OFFSET);



	spin_unlock(&spinlock);

}



static void xwdt_stop(void)

{

	spin_lock(&spinlock);



	control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);



	iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK),

				xdev.base + XWT_TWCSR0_OFFSET);



	iowrite32(0, xdev.base + XWT_TWCSR1_OFFSET);



	spin_unlock(&spinlock);

	printk(KERN_INFO PFX "Stopped!\n");

}



static void xwdt_keepalive(void)

{

	spin_lock(&spinlock);



	control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);

	control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);

	iowrite32(control_status_reg, xdev.base + XWT_TWCSR0_OFFSET);



	spin_unlock(&spinlock);

}



static void xwdt_get_status(int *status)

{

	int new_status;



	spin_lock(&spinlock);



	control_status_reg = ioread32(xdev.base + XWT_TWCSR0_OFFSET);

	new_status = ((control_status_reg &

			(XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK)) != 0);

	spin_unlock(&spinlock);



	*status = 0;

	if (new_status & 1)

		*status |= WDIOF_CARDRESET;

}



static u32 xwdt_selftest(void)

{

	int i;

	u32 timer_value1;

	u32 timer_value2;



	spin_lock(&spinlock);



	timer_value1 = ioread32(xdev.base + XWT_TBR_OFFSET);

	timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET);



	for (i = 0;

		((i <= XWT_MAX_SELFTEST_LOOP_COUNT) &&

			(timer_value2 == timer_value1)); i++) {

		timer_value2 = ioread32(xdev.base + XWT_TBR_OFFSET);

	}



	spin_unlock(&spinlock);



	if (timer_value2 != timer_value1)

		return ~XWT_TIMER_FAILED;

	else

		return XWT_TIMER_FAILED;

}



static int xwdt_open(struct inode *inode, struct file *file)

{

	/* Only one process can handle the wdt at a time */

	if (test_and_set_bit(0, &driver_open))

		return -EBUSY;



	/* Make sure that the module are always loaded...*/

	if (xdev.nowayout)

		__module_get(THIS_MODULE);



	xwdt_start();

	printk(KERN_INFO PFX "Started...\n");



	return nonseekable_open(inode, file);

}



static int xwdt_release(struct inode *inode, struct file *file)

{

	if (expect_close == 42) {

		xwdt_stop();

	} else {

		printk(KERN_CRIT PFX

			"Unexpected close, not stopping watchdog!\n");

		xwdt_keepalive();

	}



	clear_bit(0, &driver_open);

	expect_close = 0;

	return 0;

}



/*

 *      xwdt_write:

 *      @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. Any

 *      write of data will do, as we don't define content meaning.

 */

static ssize_t xwdt_write(struct file *file, const char __user *buf,

						size_t len, loff_t *ppos)

{

	if (len) {

		if (!xdev.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, buf + i))

					return -EFAULT;

				if (c == 'V')

					expect_close = 42;

			}

		}

		xwdt_keepalive();

	}

	return len;

}



static const struct watchdog_info ident = {

	.options =  WDIOF_MAGICCLOSE |

		    WDIOF_KEEPALIVEPING,

	.firmware_version =	1,

	.identity =	WATCHDOG_NAME,

};



/*

 *      xwdt_ioctl:

 *      @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.

 */

static long xwdt_ioctl(struct file *file, unsigned int cmd, unsigned long arg)

{

	int status;



	union {

		struct watchdog_info __user *ident;

		int __user *i;

	} uarg;



	uarg.i = (int __user *)arg;



	switch (cmd) {

	case WDIOC_GETSUPPORT:

		return copy_to_user(uarg.ident, &ident,

					sizeof(ident)) ? -EFAULT : 0;



	case WDIOC_GETBOOTSTATUS:

		return put_user(xdev.boot_status, uarg.i);



	case WDIOC_GETSTATUS:

		xwdt_get_status(&status);

		return put_user(status, uarg.i);



	case WDIOC_KEEPALIVE:

		xwdt_keepalive();

		return 0;



	case WDIOC_GETTIMEOUT:

		if (no_timeout)

			return -ENOTTY;

		else

			return put_user(timeout, uarg.i);



	default:

		return -ENOTTY;

	}

}



static const struct file_operations xwdt_fops = {

	.owner      = THIS_MODULE,

	.llseek     = no_llseek,

	.write      = xwdt_write,

	.open       = xwdt_open,

	.release    = xwdt_release,

	.unlocked_ioctl = xwdt_ioctl,

};



static struct miscdevice xwdt_miscdev = {

	.minor      = WATCHDOG_MINOR,

	.name       = "watchdog",

	.fops       = &xwdt_fops,

};



static int __devinit xwdt_probe(struct platform_device *pdev)

{

	int rc;

	u32 *tmptr;

	u32 *pfreq;



	no_timeout = 0;



	pfreq = (u32 *)of_get_property(pdev->dev.of_node->parent,

					"clock-frequency", NULL);



	if (pfreq == NULL) {

		printk(KERN_WARNING PFX

			"The watchdog clock frequency cannot be obtained!\n");

		no_timeout = 1;

	}



	rc = of_address_to_resource(pdev->dev.of_node, 0, &xdev.res);

	if (rc) {

		printk(KERN_WARNING PFX "invalid address!\n");

		return rc;

	}



	tmptr = (u32 *)of_get_property(pdev->dev.of_node,

					"xlnx,wdt-interval", NULL);

	if (tmptr == NULL) {

		printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-interval\""

					" not found in device tree!\n");

		no_timeout = 1;

	} else {

		xdev.wdt_interval = *tmptr;

	}



	tmptr = (u32 *)of_get_property(pdev->dev.of_node,

					"xlnx,wdt-enable-once", NULL);

	if (tmptr == NULL) {

		printk(KERN_WARNING PFX "Parameter \"xlnx,wdt-enable-once\""

					" not found in device tree!\n");

		xdev.nowayout = WATCHDOG_NOWAYOUT;

	}



/*

 *  Twice of the 2^wdt_interval / freq  because the first wdt overflow is

 *  ignored (interrupt), reset is only generated at second wdt overflow

 */

	if (!no_timeout)

		timeout = 2 * ((1<<xdev.wdt_interval) / *pfreq);



	if (!request_mem_region(xdev.res.start,

			xdev.res.end - xdev.res.start + 1, WATCHDOG_NAME)) {

		rc = -ENXIO;

		printk(KERN_ERR PFX "memory request failure!\n");

		goto err_out;

	}



	xdev.base = ioremap(xdev.res.start, xdev.res.end - xdev.res.start + 1);

	if (xdev.base == NULL) {

		rc = -ENOMEM;

		printk(KERN_ERR PFX "ioremap failure!\n");

		goto release_mem;

	}



	rc = xwdt_selftest();

	if (rc == XWT_TIMER_FAILED) {

		printk(KERN_ERR PFX "SelfTest routine error!\n");

		goto unmap_io;

	}



	xwdt_get_status(&xdev.boot_status);



	rc = misc_register(&xwdt_miscdev);

	if (rc) {

		printk(KERN_ERR PFX

			"cannot register miscdev on minor=%d (err=%d)\n",

						xwdt_miscdev.minor, rc);

		goto unmap_io;

	}



	if (no_timeout)

		printk(KERN_INFO PFX

			"driver loaded (timeout=? sec, nowayout=%d)\n",

						    xdev.nowayout);

	else

		printk(KERN_INFO PFX

			"driver loaded (timeout=%d sec, nowayout=%d)\n",

					timeout, xdev.nowayout);



	expect_close = 0;

	clear_bit(0, &driver_open);



	return 0;



unmap_io:

	iounmap(xdev.base);

release_mem:

	release_mem_region(xdev.res.start, resource_size(&xdev.res));

err_out:

	return rc;

}



static int __devexit xwdt_remove(struct platform_device *dev)

{

	misc_deregister(&xwdt_miscdev);

	iounmap(xdev.base);

	release_mem_region(xdev.res.start, resource_size(&xdev.res));



	return 0;

}



/* Match table for of_platform binding */

static struct of_device_id __devinitdata xwdt_of_match[] = {

	{ .compatible = "xlnx,xps-timebase-wdt-1.01.a", },

	{},

};

MODULE_DEVICE_TABLE(of, xwdt_of_match);



static struct platform_driver xwdt_driver = {

	.probe       = xwdt_probe,

	.remove      = __devexit_p(xwdt_remove),

	.driver = {

		.owner = THIS_MODULE,

		.name  = WATCHDOG_NAME,

		.of_match_table = xwdt_of_match,

	},

};



static int __init xwdt_init(void)

{

	return platform_driver_register(&xwdt_driver);

}



static void __exit xwdt_exit(void)

{

	platform_driver_unregister(&xwdt_driver);

}



module_init(xwdt_init);

module_exit(xwdt_exit);



MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");

MODULE_DESCRIPTION("Xilinx Watchdog driver");

MODULE_LICENSE("GPL");

MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);

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