drivers/watchdog/pseries-wdt.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * Copyright (c) 2022 International Business Machines, Inc.
  */

 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/limits.h>
 #include <linux/math.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
 #include <linux/platform_device.h>
 #include <linux/time64.h>
 #include <linux/watchdog.h>

 #define DRV_NAME "pseries-wdt"

 /*
  * H_WATCHDOG Input
  *
  * R4: "flags":
  *
  *         Bits 48-55: "operation"
  */
 #define PSERIES_WDTF_OP_START	0x100UL		/* start timer */
 #define PSERIES_WDTF_OP_STOP	0x200UL		/* stop timer */
 #define PSERIES_WDTF_OP_QUERY	0x300UL		/* query timer capabilities */

 /*
  *         Bits 56-63: "timeoutAction" (for "Start Watchdog" only)
  */
 #define PSERIES_WDTF_ACTION_HARD_POWEROFF	0x1UL	/* poweroff */
 #define PSERIES_WDTF_ACTION_HARD_RESTART	0x2UL	/* restart */
 #define PSERIES_WDTF_ACTION_DUMP_RESTART	0x3UL	/* dump + restart */

 /*
  * H_WATCHDOG Output
  *
  * R3: Return code
  *
  *     H_SUCCESS    The operation completed.
  *
  *     H_BUSY	    The hypervisor is too busy; retry the operation.
  *
  *     H_PARAMETER  The given "flags" are somehow invalid.  Either the
  *                  "operation" or "timeoutAction" is invalid, or a
  *                  reserved bit is set.
  *
  *     H_P2         The given "watchdogNumber" is zero or exceeds the
  *                  supported maximum value.
  *
  *     H_P3         The given "timeoutInMs" is below the supported
  *                  minimum value.
  *
  *     H_NOOP       The given "watchdogNumber" is already stopped.
  *
  *     H_HARDWARE   The operation failed for ineffable reasons.
  *
  *     H_FUNCTION   The H_WATCHDOG hypercall is not supported by this
  *                  hypervisor.
  *
  * R4:
  *
  * - For the "Query Watchdog Capabilities" operation, a 64-bit
  *   structure:
  */
 #define PSERIES_WDTQ_MIN_TIMEOUT(cap)	(((cap) >> 48) & 0xffff)
 #define PSERIES_WDTQ_MAX_NUMBER(cap)	(((cap) >> 32) & 0xffff)

 static const unsigned long pseries_wdt_action[] = {
 	[0] = PSERIES_WDTF_ACTION_HARD_POWEROFF,
 	[1] = PSERIES_WDTF_ACTION_HARD_RESTART,
 	[2] = PSERIES_WDTF_ACTION_DUMP_RESTART,
 };

 #define WATCHDOG_ACTION 1
 static unsigned int action = WATCHDOG_ACTION;
 module_param(action, uint, 0444);
 MODULE_PARM_DESC(action, "Action taken when watchdog expires (default="
 		 __MODULE_STRING(WATCHDOG_ACTION) ")");

 static bool nowayout = WATCHDOG_NOWAYOUT;
 module_param(nowayout, bool, 0444);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

 #define WATCHDOG_TIMEOUT 60
 static unsigned int timeout = WATCHDOG_TIMEOUT;
 module_param(timeout, uint, 0444);
 MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds (default="
 		 __MODULE_STRING(WATCHDOG_TIMEOUT) ")");

 struct pseries_wdt {
 	struct watchdog_device wd;
 	unsigned long action;
 	unsigned long num;		/* Watchdog numbers are 1-based */
 };

 static int pseries_wdt_start(struct watchdog_device *wdd)
 {
 	struct pseries_wdt *pw = watchdog_get_drvdata(wdd);
 	struct device *dev = wdd->parent;
 	unsigned long flags, msecs;
 	long rc;

 	flags = pw->action | PSERIES_WDTF_OP_START;
 	msecs = wdd->timeout * MSEC_PER_SEC;
 	rc = plpar_hcall_norets(H_WATCHDOG, flags, pw->num, msecs);
 	if (rc != H_SUCCESS) {
 		dev_crit(dev, "H_WATCHDOG: %ld: failed to start timer %lu",
 			 rc, pw->num);
 		return -EIO;
 	}
 	return 0;
 }

 static int pseries_wdt_stop(struct watchdog_device *wdd)
 {
 	struct pseries_wdt *pw = watchdog_get_drvdata(wdd);
 	struct device *dev = wdd->parent;
 	long rc;

 	rc = plpar_hcall_norets(H_WATCHDOG, PSERIES_WDTF_OP_STOP, pw->num);
 	if (rc != H_SUCCESS && rc != H_NOOP) {
 		dev_crit(dev, "H_WATCHDOG: %ld: failed to stop timer %lu",
 			 rc, pw->num);
 		return -EIO;
 	}
 	return 0;
 }

 static struct watchdog_info pseries_wdt_info = {
 	.identity = DRV_NAME,
 	.options = WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT
 	    | WDIOF_PRETIMEOUT,
 };

 static const struct watchdog_ops pseries_wdt_ops = {
 	.owner = THIS_MODULE,
 	.start = pseries_wdt_start,
 	.stop = pseries_wdt_stop,
 };

 static int pseries_wdt_probe(struct platform_device *pdev)
 {
 	unsigned long ret[PLPAR_HCALL_BUFSIZE] = { 0 };
 	struct pseries_wdt *pw;
 	unsigned long cap;
 	long msecs, rc;
 	int err;

 	rc = plpar_hcall(H_WATCHDOG, ret, PSERIES_WDTF_OP_QUERY);
 	if (rc == H_FUNCTION)
 		return -ENODEV;
 	if (rc != H_SUCCESS)
 		return -EIO;
 	cap = ret[0];

 	pw = devm_kzalloc(&pdev->dev, sizeof(*pw), GFP_KERNEL);
 	if (!pw)
 		return -ENOMEM;

 	/*
 	 * Assume watchdogNumber 1 for now.  If we ever support
 	 * multiple timers we will need to devise a way to choose a
 	 * distinct watchdogNumber for each platform device at device
 	 * registration time.
 	 */
 	pw->num = 1;
 	if (PSERIES_WDTQ_MAX_NUMBER(cap) < pw->num)
 		return -ENODEV;

 	if (action >= ARRAY_SIZE(pseries_wdt_action))
 		return -EINVAL;
 	pw->action = pseries_wdt_action[action];

 	pw->wd.parent = &pdev->dev;
 	pw->wd.info = &pseries_wdt_info;
 	pw->wd.ops = &pseries_wdt_ops;
 	msecs = PSERIES_WDTQ_MIN_TIMEOUT(cap);
 	pw->wd.min_timeout = DIV_ROUND_UP(msecs, MSEC_PER_SEC);
 	pw->wd.max_timeout = UINT_MAX / 1000;	/* from linux/watchdog.h */
 	pw->wd.timeout = timeout;
 	if (watchdog_init_timeout(&pw->wd, 0, NULL))
 		return -EINVAL;
 	watchdog_set_nowayout(&pw->wd, nowayout);
 	watchdog_stop_on_reboot(&pw->wd);
 	watchdog_stop_on_unregister(&pw->wd);
 	watchdog_set_drvdata(&pw->wd, pw);

 	err = devm_watchdog_register_device(&pdev->dev, &pw->wd);
 	if (err)
 		return err;

 	platform_set_drvdata(pdev, &pw->wd);

 	return 0;
 }

 static int pseries_wdt_suspend(struct platform_device *pdev, pm_message_t state)
 {
 	struct watchdog_device *wd = platform_get_drvdata(pdev);

 	if (watchdog_active(wd))
 		return pseries_wdt_stop(wd);
 	return 0;
 }

 static int pseries_wdt_resume(struct platform_device *pdev)
 {
 	struct watchdog_device *wd = platform_get_drvdata(pdev);

 	if (watchdog_active(wd))
 		return pseries_wdt_start(wd);
 	return 0;
 }

 static const struct platform_device_id pseries_wdt_id[] = {
 	{ .name = "pseries-wdt" },
 	{}
 };
 MODULE_DEVICE_TABLE(platform, pseries_wdt_id);

 static struct platform_driver pseries_wdt_driver = {
 	.driver = {
 		.name = DRV_NAME,
 	},
 	.id_table = pseries_wdt_id,
 	.probe = pseries_wdt_probe,
 	.resume = pseries_wdt_resume,
 	.suspend = pseries_wdt_suspend,
 };
 module_platform_driver(pseries_wdt_driver);

 MODULE_AUTHOR("Alexey Kardashevskiy");
 MODULE_AUTHOR("Scott Cheloha");
 MODULE_DESCRIPTION("POWER Architecture Platform Watchdog Driver");
 MODULE_LICENSE("GPL");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (c) 2022 International Business Machines, Inc.
	*/

	#include <linux/bitops.h>
	#include <linux/kernel.h>
	#include <linux/limits.h>
	#include <linux/math.h>
	#include <linux/mod_devicetable.h>
	#include <linux/module.h>
	#include <linux/moduleparam.h>
	#include <linux/platform_device.h>
	#include <linux/time64.h>
	#include <linux/watchdog.h>

	#define DRV_NAME "pseries-wdt"

	/*
	* H_WATCHDOG Input
	*
	* R4: "flags":
	*
	* Bits 48-55: "operation"
	*/
	#define PSERIES_WDTF_OP_START 0x100UL /* start timer */
	#define PSERIES_WDTF_OP_STOP 0x200UL /* stop timer */
	#define PSERIES_WDTF_OP_QUERY 0x300UL /* query timer capabilities */

	/*
	* Bits 56-63: "timeoutAction" (for "Start Watchdog" only)
	*/
	#define PSERIES_WDTF_ACTION_HARD_POWEROFF 0x1UL /* poweroff */
	#define PSERIES_WDTF_ACTION_HARD_RESTART 0x2UL /* restart */
	#define PSERIES_WDTF_ACTION_DUMP_RESTART 0x3UL /* dump + restart */

	/*
	* H_WATCHDOG Output
	*
	* R3: Return code
	*
	* H_SUCCESS The operation completed.
	*
	* H_BUSY The hypervisor is too busy; retry the operation.
	*
	* H_PARAMETER The given "flags" are somehow invalid. Either the
	* "operation" or "timeoutAction" is invalid, or a
	* reserved bit is set.
	*
	* H_P2 The given "watchdogNumber" is zero or exceeds the
	* supported maximum value.
	*
	* H_P3 The given "timeoutInMs" is below the supported
	* minimum value.
	*
	* H_NOOP The given "watchdogNumber" is already stopped.
	*
	* H_HARDWARE The operation failed for ineffable reasons.
	*
	* H_FUNCTION The H_WATCHDOG hypercall is not supported by this
	* hypervisor.
	*
	* R4:
	*
	* - For the "Query Watchdog Capabilities" operation, a 64-bit
	* structure:
	*/
	#define PSERIES_WDTQ_MIN_TIMEOUT(cap) (((cap) >> 48) & 0xffff)
	#define PSERIES_WDTQ_MAX_NUMBER(cap) (((cap) >> 32) & 0xffff)

	static const unsigned long pseries_wdt_action[] = {
	[0] = PSERIES_WDTF_ACTION_HARD_POWEROFF,
	[1] = PSERIES_WDTF_ACTION_HARD_RESTART,
	[2] = PSERIES_WDTF_ACTION_DUMP_RESTART,
	};

	#define WATCHDOG_ACTION 1
	static unsigned int action = WATCHDOG_ACTION;
	module_param(action, uint, 0444);
	MODULE_PARM_DESC(action, "Action taken when watchdog expires (default="
	__MODULE_STRING(WATCHDOG_ACTION) ")");

	static bool nowayout = WATCHDOG_NOWAYOUT;
	module_param(nowayout, bool, 0444);
	MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
	__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

	#define WATCHDOG_TIMEOUT 60
	static unsigned int timeout = WATCHDOG_TIMEOUT;
	module_param(timeout, uint, 0444);
	MODULE_PARM_DESC(timeout, "Initial watchdog timeout in seconds (default="
	__MODULE_STRING(WATCHDOG_TIMEOUT) ")");

	struct pseries_wdt {
	struct watchdog_device wd;
	unsigned long action;
	unsigned long num; /* Watchdog numbers are 1-based */
	};

	static int pseries_wdt_start(struct watchdog_device *wdd)
	{
	struct pseries_wdt *pw = watchdog_get_drvdata(wdd);
	struct device *dev = wdd->parent;
	unsigned long flags, msecs;
	long rc;

	flags = pw->action \| PSERIES_WDTF_OP_START;
	msecs = wdd->timeout * MSEC_PER_SEC;
	rc = plpar_hcall_norets(H_WATCHDOG, flags, pw->num, msecs);
	if (rc != H_SUCCESS) {
	dev_crit(dev, "H_WATCHDOG: %ld: failed to start timer %lu",
	rc, pw->num);
	return -EIO;
	}
	return 0;
	}

	static int pseries_wdt_stop(struct watchdog_device *wdd)
	{
	struct pseries_wdt *pw = watchdog_get_drvdata(wdd);
	struct device *dev = wdd->parent;
	long rc;

	rc = plpar_hcall_norets(H_WATCHDOG, PSERIES_WDTF_OP_STOP, pw->num);
	if (rc != H_SUCCESS && rc != H_NOOP) {
	dev_crit(dev, "H_WATCHDOG: %ld: failed to stop timer %lu",
	rc, pw->num);
	return -EIO;
	}
	return 0;
	}

	static struct watchdog_info pseries_wdt_info = {
	.identity = DRV_NAME,
	.options = WDIOF_KEEPALIVEPING \| WDIOF_MAGICCLOSE \| WDIOF_SETTIMEOUT
	\| WDIOF_PRETIMEOUT,
	};

	static const struct watchdog_ops pseries_wdt_ops = {
	.owner = THIS_MODULE,
	.start = pseries_wdt_start,
	.stop = pseries_wdt_stop,
	};

	static int pseries_wdt_probe(struct platform_device *pdev)
	{
	unsigned long ret[PLPAR_HCALL_BUFSIZE] = { 0 };
	struct pseries_wdt *pw;
	unsigned long cap;
	long msecs, rc;
	int err;

	rc = plpar_hcall(H_WATCHDOG, ret, PSERIES_WDTF_OP_QUERY);
	if (rc == H_FUNCTION)
	return -ENODEV;
	if (rc != H_SUCCESS)
	return -EIO;
	cap = ret[0];

	pw = devm_kzalloc(&pdev->dev, sizeof(*pw), GFP_KERNEL);
	if (!pw)
	return -ENOMEM;

	/*
	* Assume watchdogNumber 1 for now. If we ever support
	* multiple timers we will need to devise a way to choose a
	* distinct watchdogNumber for each platform device at device
	* registration time.
	*/
	pw->num = 1;
	if (PSERIES_WDTQ_MAX_NUMBER(cap) < pw->num)
	return -ENODEV;

	if (action >= ARRAY_SIZE(pseries_wdt_action))
	return -EINVAL;
	pw->action = pseries_wdt_action[action];

	pw->wd.parent = &pdev->dev;
	pw->wd.info = &pseries_wdt_info;
	pw->wd.ops = &pseries_wdt_ops;
	msecs = PSERIES_WDTQ_MIN_TIMEOUT(cap);
	pw->wd.min_timeout = DIV_ROUND_UP(msecs, MSEC_PER_SEC);
	pw->wd.max_timeout = UINT_MAX / 1000; /* from linux/watchdog.h */
	pw->wd.timeout = timeout;
	if (watchdog_init_timeout(&pw->wd, 0, NULL))
	return -EINVAL;
	watchdog_set_nowayout(&pw->wd, nowayout);
	watchdog_stop_on_reboot(&pw->wd);
	watchdog_stop_on_unregister(&pw->wd);
	watchdog_set_drvdata(&pw->wd, pw);

	err = devm_watchdog_register_device(&pdev->dev, &pw->wd);
	if (err)
	return err;

	platform_set_drvdata(pdev, &pw->wd);

	return 0;
	}

	static int pseries_wdt_suspend(struct platform_device *pdev, pm_message_t state)
	{
	struct watchdog_device *wd = platform_get_drvdata(pdev);

	if (watchdog_active(wd))
	return pseries_wdt_stop(wd);
	return 0;
	}

	static int pseries_wdt_resume(struct platform_device *pdev)
	{
	struct watchdog_device *wd = platform_get_drvdata(pdev);

	if (watchdog_active(wd))
	return pseries_wdt_start(wd);
	return 0;
	}

	static const struct platform_device_id pseries_wdt_id[] = {
	{ .name = "pseries-wdt" },
	{}
	};
	MODULE_DEVICE_TABLE(platform, pseries_wdt_id);

	static struct platform_driver pseries_wdt_driver = {
	.driver = {
	.name = DRV_NAME,
	},
	.id_table = pseries_wdt_id,
	.probe = pseries_wdt_probe,
	.resume = pseries_wdt_resume,
	.suspend = pseries_wdt_suspend,
	};
	module_platform_driver(pseries_wdt_driver);

	MODULE_AUTHOR("Alexey Kardashevskiy");
	MODULE_AUTHOR("Scott Cheloha");
	MODULE_DESCRIPTION("POWER Architecture Platform Watchdog Driver");
	MODULE_LICENSE("GPL");