watchdog: Add Xilinx watchdog timer driver (e9659e69) · Commits · e / devices / android_kernel_sony_msm8994

drivers/watchdog/Kconfig

+14 −0

Original line number	Original line	Diff line number	Diff line
	@@ -888,6 +888,20 @@ config M54xx_WATCHDOG
	To compile this driver as a module, choose M here: the		To compile this driver as a module, choose M here: the
	module will be called m54xx_wdt.		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		# MIPS Architecture

	config ATH79_WDT		config ATH79_WDT

drivers/watchdog/Makefile

+3 −0

Original line number	Original line	Diff line number	Diff line
	@@ -110,6 +110,9 @@ obj-$(CONFIG_INTEL_SCU_WATCHDOG) += intel_scu_watchdog.o
	# M68K Architecture		# M68K Architecture
	obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o		obj-$(CONFIG_M54xx_WATCHDOG) += m54xx_wdt.o

			# MicroBlaze Architecture
			obj-$(CONFIG_XILINX_WATCHDOG) += of_xilinx_wdt.o

	# MIPS Architecture		# MIPS Architecture
	obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o		obj-$(CONFIG_ATH79_WDT) += ath79_wdt.o
	obj-$(CONFIG_BCM47XX_WDT) += bcm47xx_wdt.o		obj-$(CONFIG_BCM47XX_WDT) += bcm47xx_wdt.o

drivers/watchdog/of_xilinx_wdt.c

0 → 100644

+433 −0

Original line number	Original line	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);