/*
 * Copyright (C) 2017 NXP.
 *
 * 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.
 */

#include <linux/arm-smccc.h>
#include <linux/io.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/watchdog.h>
#include <soc/imx/fsl_sip.h>
#include <soc/imx8/sc/sci.h>
#include <soc/imx8/sc/svc/irq/api.h>

#define DEFAULT_TIMEOUT 60
/*
 * Software timer tick implemented in scfw side, support 10ms to 0xffffffff ms
 * in theory, but for normal case, 1s~128s is enough, you can change this max
 * value in case it's not enough.
 */
#define MAX_TIMEOUT 128

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0000);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static unsigned int timeout = DEFAULT_TIMEOUT;
module_param(timeout, uint, 0000);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds 1<= timeout <="
				__MODULE_STRING(MAX_TIMEOUT) " (default="
				__MODULE_STRING(DEFAULT_TIMEOUT) ")");

static struct watchdog_device imx8_wdd;

static int imx8_wdt_notify(struct notifier_block *nb,
				      unsigned long event, void *group)
{
	/* ignore other irqs */
	if (!(event & SC_IRQ_WDOG &&
		(*(sc_irq_group_t *)group == SC_IRQ_GROUP_WDOG)))
		return 0;

	watchdog_notify_pretimeout(&imx8_wdd);

	return 0;
}

static int imx8_wdt_ping(struct watchdog_device *wdog)
{
	struct arm_smccc_res res;

	arm_smccc_smc(FSL_SIP_SRTC, FSL_SIP_SRTC_PING_WDOG, 0, 0, 0, 0, 0, 0,
			&res);

	return res.a0;
}

static int imx8_wdt_start(struct watchdog_device *wdog)
{
	struct arm_smccc_res res;

	/* no block */
	arm_smccc_smc(FSL_SIP_SRTC, FSL_SIP_SRTC_START_WDOG, 0, 0, 0, 0, 0, 0,
			&res);
	if (res.a0)
		return res.a0;

	dev_dbg(wdog->parent, "Watchdog started\n");

	return 0;
}

static int imx8_wdt_stop(struct watchdog_device *wdog)
{
	struct arm_smccc_res res;

	arm_smccc_smc(FSL_SIP_SRTC, FSL_SIP_SRTC_STOP_WDOG, 0, 0, 0, 0, 0, 0,
			&res);

	dev_dbg(wdog->parent, "Watchdog stopped\n");

	return res.a0;
}

static int imx8_wdt_set_timeout(struct watchdog_device *wdog,
				unsigned int timeout)
{
	struct arm_smccc_res res;

	wdog->timeout = timeout;

	arm_smccc_smc(FSL_SIP_SRTC, FSL_SIP_SRTC_SET_TIMEOUT_WDOG,
			timeout * 1000, 0, 0, 0, 0, 0, &res);

	dev_dbg(wdog->parent, "Set timeout to %d seconds\n", timeout);

	return res.a0;
}

static int imx8_wdt_set_pretimeout(struct watchdog_device *wdog,
				   unsigned int new_pretimeout)
{
	struct arm_smccc_res res;

	/*
	 * SCU firmware calculates pretimeout based on current time
	 * stamp instead of watchdog timeout stamp, need to convert
	 * the pretimeout to SCU firmware's timeout value.
	 */
	arm_smccc_smc(FSL_SIP_SRTC, FSL_SIP_SRTC_SET_PRETIME_WDOG,
		      (wdog->timeout - new_pretimeout) * 1000, 0, 0, 0,
		      0, 0, &res);

	dev_dbg(wdog->parent, "Set pretimeout to %d seconds\n", new_pretimeout);

	return res.a0;
}

static const struct watchdog_ops imx8_wdt_ops = {
	.owner = THIS_MODULE,
	.start = imx8_wdt_start,
	.stop  = imx8_wdt_stop,
	.ping  = imx8_wdt_ping,
	.set_timeout = imx8_wdt_set_timeout,
	.set_pretimeout = imx8_wdt_set_pretimeout,
};

static const struct watchdog_info imx8_wdt_info = {
	.identity	= "i.MX8 watchdog timer",
	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
			  WDIOF_MAGICCLOSE | WDIOF_PRETIMEOUT,
};

static struct notifier_block imx8_wdt_notifier = {
	.notifier_call = imx8_wdt_notify,
};

#ifdef CONFIG_PM_SLEEP
static int imx8_wdt_suspend(struct device *dev)
{
	if (test_bit(WDOG_ACTIVE, &imx8_wdd.status))
		imx8_wdt_stop(&imx8_wdd);

	return 0;
}

static int imx8_wdt_resume(struct device *dev)
{
	if (test_bit(WDOG_ACTIVE, &imx8_wdd.status))
		imx8_wdt_start(&imx8_wdd);

	return 0;
}

static const struct dev_pm_ops imx8_wdt_pm_ops = {
	.suspend = imx8_wdt_suspend,
	.resume = imx8_wdt_resume,
};

#define IMX8_WDT_PM_OPS	(&imx8_wdt_pm_ops)

#else

#define IMX8_WDT_PM_OPS	NULL

#endif

static int imx8_wdt_probe(struct platform_device *pdev)
{
	struct watchdog_device *wdt = &imx8_wdd;
	int err;

	platform_set_drvdata(pdev, wdt);
	/* init the wdd */
	wdt->info = &imx8_wdt_info;
	wdt->ops = &imx8_wdt_ops;
	wdt->min_timeout = 1;
	wdt->max_timeout = MAX_TIMEOUT;
	wdt->parent = &pdev->dev;
	watchdog_set_drvdata(wdt, NULL);

	err = watchdog_init_timeout(wdt, timeout, &pdev->dev);
	if (err) {
		dev_err(&pdev->dev, "Failed to init watchdog timeout:%d\n", err);
		return err;
	}

	err = watchdog_register_device(wdt);
	if (err) {
		dev_err(&pdev->dev, "Failed to register watchdog device: %d\n", err);
		return err;
	}

	err = register_scu_notifier(&imx8_wdt_notifier);
	if (err) {
		dev_err(&pdev->dev, "Failed to register scu notifier: %d\n", err);
		goto scu_err;
	}

	dev_info(&pdev->dev, "initialized (timeout=%d sec, nowayout=%d)\n",
		 timeout, nowayout);

	return 0;

scu_err:
	watchdog_unregister_device(wdt);

	return err;
}

static int imx8_wdt_remove(struct platform_device *pdev)
{
	struct watchdog_device *wdt = platform_get_drvdata(pdev);

	imx8_wdt_stop(wdt);

	unregister_scu_notifier(&imx8_wdt_notifier);

	watchdog_unregister_device(wdt);

	return 0;
}

static void imx8_wdt_shutdown(struct platform_device *pdev)
{
	struct watchdog_device *wdt = platform_get_drvdata(pdev);

	if (watchdog_active(wdt))
		imx8_wdt_stop(wdt);
}

static const struct of_device_id imx8_wdt_dt_ids[] = {
	{ .compatible = "fsl,imx8-wdt", },
	{ /*sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx8_wdt_dt_ids);

static struct platform_driver imx8_wdt_driver = {
	.probe		= imx8_wdt_probe,
	.remove		= imx8_wdt_remove,
	.shutdown	= imx8_wdt_shutdown,
	.driver		= {
		.name	= "imx8-wdt",
		.of_match_table = imx8_wdt_dt_ids,
		.pm	= IMX8_WDT_PM_OPS,
	},
};

module_platform_driver(imx8_wdt_driver);

MODULE_AUTHOR("Robin Gong <yibin.gong@nxp.com>");
MODULE_DESCRIPTION("NXP i.MX8 watchdog driver");
MODULE_LICENSE("GPL v2");