drivers/watchdog/of_xilinx_wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Watchdog Device Driver for Xilinx axi/xps_timebase_wdt
  *
  * (C) Copyright 2013 - 2014 Xilinx, Inc.
  * (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
  */

 #include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/ioport.h>
 #include <linux/watchdog.h>
 #include <linux/io.h>
 #include <linux/of.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	BIT(3) /* Reset status */
 #define XWT_CSR0_WDS_MASK	BIT(2) /* Timer state  */
 #define XWT_CSR0_EWDT1_MASK	BIT(1) /* Enable bit 1 */

 /* Control/Status Register 0/1 bits  */
 #define XWT_CSRX_EWDT2_MASK	BIT(0) /* Enable bit 2 */

 /* SelfTest constants */
 #define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000
 #define XWT_TIMER_FAILED            0xFFFFFFFF

 #define WATCHDOG_NAME     "Xilinx Watchdog"

 struct xwdt_device {
 	void __iomem *base;
 	u32 wdt_interval;
 	spinlock_t spinlock; /* spinlock for register handling */
 	struct watchdog_device xilinx_wdt_wdd;
 	struct clk		*clk;
 };

 static int xilinx_wdt_start(struct watchdog_device *wdd)
 {
 	int ret;
 	u32 control_status_reg;
 	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

 	ret = clk_enable(xdev->clk);
 	if (ret) {
 		dev_err(wdd->parent, "Failed to enable clock\n");
 		return ret;
 	}

 	spin_lock(&xdev->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(&xdev->spinlock);

 	dev_dbg(wdd->parent, "Watchdog Started!\n");

 	return 0;
 }

 static int xilinx_wdt_stop(struct watchdog_device *wdd)
 {
 	u32 control_status_reg;
 	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

 	spin_lock(&xdev->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(&xdev->spinlock);

 	clk_disable(xdev->clk);

 	dev_dbg(wdd->parent, "Watchdog Stopped!\n");

 	return 0;
 }

 static int xilinx_wdt_keepalive(struct watchdog_device *wdd)
 {
 	u32 control_status_reg;
 	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

 	spin_lock(&xdev->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(&xdev->spinlock);

 	return 0;
 }

 static const struct watchdog_info xilinx_wdt_ident = {
 	.options =  WDIOF_MAGICCLOSE |
 		    WDIOF_KEEPALIVEPING,
 	.firmware_version =	1,
 	.identity =	WATCHDOG_NAME,
 };

 static const struct watchdog_ops xilinx_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = xilinx_wdt_start,
 	.stop = xilinx_wdt_stop,
 	.ping = xilinx_wdt_keepalive,
 };

 static u32 xwdt_selftest(struct xwdt_device *xdev)
 {
 	int i;
 	u32 timer_value1;
 	u32 timer_value2;

 	spin_lock(&xdev->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(&xdev->spinlock);

 	if (timer_value2 != timer_value1)
 		return ~XWT_TIMER_FAILED;
 	else
 		return XWT_TIMER_FAILED;
 }

 static int xwdt_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	int rc;
 	u32 pfreq = 0, enable_once = 0;
 	struct xwdt_device *xdev;
 	struct watchdog_device *xilinx_wdt_wdd;

 	xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL);
 	if (!xdev)
 		return -ENOMEM;

 	xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
 	xilinx_wdt_wdd->info = &xilinx_wdt_ident;
 	xilinx_wdt_wdd->ops = &xilinx_wdt_ops;
 	xilinx_wdt_wdd->parent = dev;

 	xdev->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(xdev->base))
 		return PTR_ERR(xdev->base);

 	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-interval",
 				  &xdev->wdt_interval);
 	if (rc)
 		dev_warn(dev, "Parameter \"xlnx,wdt-interval\" not found\n");

 	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-enable-once",
 				  &enable_once);
 	if (rc)
 		dev_warn(dev,
 			 "Parameter \"xlnx,wdt-enable-once\" not found\n");

 	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);

 	xdev->clk = devm_clk_get_prepared(dev, NULL);
 	if (IS_ERR(xdev->clk)) {
 		if (PTR_ERR(xdev->clk) != -ENOENT)
 			return PTR_ERR(xdev->clk);

 		/*
 		 * Clock framework support is optional, continue on
 		 * anyways if we don't find a matching clock.
 		 */
 		xdev->clk = NULL;

 		rc = of_property_read_u32(dev->of_node, "clock-frequency",
 					  &pfreq);
 		if (rc)
 			dev_warn(dev,
 				 "The watchdog clock freq cannot be obtained\n");
 	} else {
 		pfreq = clk_get_rate(xdev->clk);
 	}

 	/*
 	 * Twice of the 2^wdt_interval / freq  because the first wdt overflow is
 	 * ignored (interrupt), reset is only generated at second wdt overflow
 	 */
 	if (pfreq && xdev->wdt_interval)
 		xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
 					  pfreq);

 	spin_lock_init(&xdev->spinlock);
 	watchdog_set_drvdata(xilinx_wdt_wdd, xdev);

 	rc = clk_enable(xdev->clk);
 	if (rc) {
 		dev_err(dev, "unable to enable clock\n");
 		return rc;
 	}

 	rc = xwdt_selftest(xdev);
 	if (rc == XWT_TIMER_FAILED) {
 		dev_err(dev, "SelfTest routine error\n");
 		clk_disable(xdev->clk);
 		return rc;
 	}

 	clk_disable(xdev->clk);

 	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
 	if (rc)
 		return rc;

 	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds\n",
 		 xilinx_wdt_wdd->timeout);

 	platform_set_drvdata(pdev, xdev);

 	return 0;
 }

 /**
  * xwdt_suspend - Suspend the device.
  *
  * @dev: handle to the device structure.
  * Return: 0 always.
  */
 static int __maybe_unused xwdt_suspend(struct device *dev)
 {
 	struct xwdt_device *xdev = dev_get_drvdata(dev);

 	if (watchdog_active(&xdev->xilinx_wdt_wdd))
 		xilinx_wdt_stop(&xdev->xilinx_wdt_wdd);

 	return 0;
 }

 /**
  * xwdt_resume - Resume the device.
  *
  * @dev: handle to the device structure.
  * Return: 0 on success, errno otherwise.
  */
 static int __maybe_unused xwdt_resume(struct device *dev)
 {
 	struct xwdt_device *xdev = dev_get_drvdata(dev);
 	int ret = 0;

 	if (watchdog_active(&xdev->xilinx_wdt_wdd))
 		ret = xilinx_wdt_start(&xdev->xilinx_wdt_wdd);

 	return ret;
 }

 static SIMPLE_DEV_PM_OPS(xwdt_pm_ops, xwdt_suspend, xwdt_resume);

 /* Match table for of_platform binding */
 static const struct of_device_id xwdt_of_match[] = {
 	{ .compatible = "xlnx,xps-timebase-wdt-1.00.a", },
 	{ .compatible = "xlnx,xps-timebase-wdt-1.01.a", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, xwdt_of_match);

 static struct platform_driver xwdt_driver = {
 	.probe       = xwdt_probe,
 	.driver = {
 		.name  = WATCHDOG_NAME,
 		.of_match_table = xwdt_of_match,
 		.pm = &xwdt_pm_ops,
 	},
 };

 module_platform_driver(xwdt_driver);

 MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
 MODULE_DESCRIPTION("Xilinx Watchdog driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* Watchdog Device Driver for Xilinx axi/xps_timebase_wdt
	*
	* (C) Copyright 2013 - 2014 Xilinx, Inc.
	* (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
	*/

	#include <linux/bits.h>
	#include <linux/clk.h>
	#include <linux/err.h>
	#include <linux/module.h>
	#include <linux/platform_device.h>
	#include <linux/types.h>
	#include <linux/kernel.h>
	#include <linux/ioport.h>
	#include <linux/watchdog.h>
	#include <linux/io.h>
	#include <linux/of.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 BIT(3) /* Reset status */
	#define XWT_CSR0_WDS_MASK BIT(2) /* Timer state */
	#define XWT_CSR0_EWDT1_MASK BIT(1) /* Enable bit 1 */

	/* Control/Status Register 0/1 bits */
	#define XWT_CSRX_EWDT2_MASK BIT(0) /* Enable bit 2 */

	/* SelfTest constants */
	#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000
	#define XWT_TIMER_FAILED 0xFFFFFFFF

	#define WATCHDOG_NAME "Xilinx Watchdog"

	struct xwdt_device {
	void __iomem *base;
	u32 wdt_interval;
	spinlock_t spinlock; /* spinlock for register handling */
	struct watchdog_device xilinx_wdt_wdd;
	struct clk *clk;
	};

	static int xilinx_wdt_start(struct watchdog_device *wdd)
	{
	int ret;
	u32 control_status_reg;
	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

	ret = clk_enable(xdev->clk);
	if (ret) {
	dev_err(wdd->parent, "Failed to enable clock\n");
	return ret;
	}

	spin_lock(&xdev->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(&xdev->spinlock);

	dev_dbg(wdd->parent, "Watchdog Started!\n");

	return 0;
	}

	static int xilinx_wdt_stop(struct watchdog_device *wdd)
	{
	u32 control_status_reg;
	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

	spin_lock(&xdev->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(&xdev->spinlock);

	clk_disable(xdev->clk);

	dev_dbg(wdd->parent, "Watchdog Stopped!\n");

	return 0;
	}

	static int xilinx_wdt_keepalive(struct watchdog_device *wdd)
	{
	u32 control_status_reg;
	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);

	spin_lock(&xdev->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(&xdev->spinlock);

	return 0;
	}

	static const struct watchdog_info xilinx_wdt_ident = {
	.options = WDIOF_MAGICCLOSE \|
	WDIOF_KEEPALIVEPING,
	.firmware_version = 1,
	.identity = WATCHDOG_NAME,
	};

	static const struct watchdog_ops xilinx_wdt_ops = {
	.owner = THIS_MODULE,
	.start = xilinx_wdt_start,
	.stop = xilinx_wdt_stop,
	.ping = xilinx_wdt_keepalive,
	};

	static u32 xwdt_selftest(struct xwdt_device *xdev)
	{
	int i;
	u32 timer_value1;
	u32 timer_value2;

	spin_lock(&xdev->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(&xdev->spinlock);

	if (timer_value2 != timer_value1)
	return ~XWT_TIMER_FAILED;
	else
	return XWT_TIMER_FAILED;
	}

	static int xwdt_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	int rc;
	u32 pfreq = 0, enable_once = 0;
	struct xwdt_device *xdev;
	struct watchdog_device *xilinx_wdt_wdd;

	xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL);
	if (!xdev)
	return -ENOMEM;

	xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
	xilinx_wdt_wdd->info = &xilinx_wdt_ident;
	xilinx_wdt_wdd->ops = &xilinx_wdt_ops;
	xilinx_wdt_wdd->parent = dev;

	xdev->base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(xdev->base))
	return PTR_ERR(xdev->base);

	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-interval",
	&xdev->wdt_interval);
	if (rc)
	dev_warn(dev, "Parameter \"xlnx,wdt-interval\" not found\n");

	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-enable-once",
	&enable_once);
	if (rc)
	dev_warn(dev,
	"Parameter \"xlnx,wdt-enable-once\" not found\n");

	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);

	xdev->clk = devm_clk_get_prepared(dev, NULL);
	if (IS_ERR(xdev->clk)) {
	if (PTR_ERR(xdev->clk) != -ENOENT)
	return PTR_ERR(xdev->clk);

	/*
	* Clock framework support is optional, continue on
	* anyways if we don't find a matching clock.
	*/
	xdev->clk = NULL;

	rc = of_property_read_u32(dev->of_node, "clock-frequency",
	&pfreq);
	if (rc)
	dev_warn(dev,
	"The watchdog clock freq cannot be obtained\n");
	} else {
	pfreq = clk_get_rate(xdev->clk);
	}

	/*
	* Twice of the 2^wdt_interval / freq because the first wdt overflow is
	* ignored (interrupt), reset is only generated at second wdt overflow
	*/
	if (pfreq && xdev->wdt_interval)
	xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
	pfreq);

	spin_lock_init(&xdev->spinlock);
	watchdog_set_drvdata(xilinx_wdt_wdd, xdev);

	rc = clk_enable(xdev->clk);
	if (rc) {
	dev_err(dev, "unable to enable clock\n");
	return rc;
	}

	rc = xwdt_selftest(xdev);
	if (rc == XWT_TIMER_FAILED) {
	dev_err(dev, "SelfTest routine error\n");
	clk_disable(xdev->clk);
	return rc;
	}

	clk_disable(xdev->clk);

	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
	if (rc)
	return rc;

	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds\n",
	xilinx_wdt_wdd->timeout);

	platform_set_drvdata(pdev, xdev);

	return 0;
	}

	/**
	* xwdt_suspend - Suspend the device.
	*
	* @dev: handle to the device structure.
	* Return: 0 always.
	*/
	static int __maybe_unused xwdt_suspend(struct device *dev)
	{
	struct xwdt_device *xdev = dev_get_drvdata(dev);

	if (watchdog_active(&xdev->xilinx_wdt_wdd))
	xilinx_wdt_stop(&xdev->xilinx_wdt_wdd);

	return 0;
	}

	/**
	* xwdt_resume - Resume the device.
	*
	* @dev: handle to the device structure.
	* Return: 0 on success, errno otherwise.
	*/
	static int __maybe_unused xwdt_resume(struct device *dev)
	{
	struct xwdt_device *xdev = dev_get_drvdata(dev);
	int ret = 0;

	if (watchdog_active(&xdev->xilinx_wdt_wdd))
	ret = xilinx_wdt_start(&xdev->xilinx_wdt_wdd);

	return ret;
	}

	static SIMPLE_DEV_PM_OPS(xwdt_pm_ops, xwdt_suspend, xwdt_resume);

	/* Match table for of_platform binding */
	static const struct of_device_id xwdt_of_match[] = {
	{ .compatible = "xlnx,xps-timebase-wdt-1.00.a", },
	{ .compatible = "xlnx,xps-timebase-wdt-1.01.a", },
	{},
	};
	MODULE_DEVICE_TABLE(of, xwdt_of_match);

	static struct platform_driver xwdt_driver = {
	.probe = xwdt_probe,
	.driver = {
	.name = WATCHDOG_NAME,
	.of_match_table = xwdt_of_match,
	.pm = &xwdt_pm_ops,
	},
	};

	module_platform_driver(xwdt_driver);

	MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
	MODULE_DESCRIPTION("Xilinx Watchdog driver");
	MODULE_LICENSE("GPL");