Commit eca10ae6 authored by Linus Walleij's avatar Linus Walleij Committed by Guenter Roeck
Browse files

watchdog: add driver for Cortina Gemini watchdog 



This add support for the Cortina systems Gemini (SL3516)
SoC watchdog.

I have tried to use all the right new kernel interfaces
and tested with busybox' "watchdog" command both to kick
and get timeouts and reboots.

Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 428a6655

drivers/watchdog/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -301,6 +301,17 @@ config 977_WATCHDOG 


	  Not sure? It's safe to say N.



config GEMINI_WATCHDOG

	tristate "Gemini watchdog"

	depends on ARCH_GEMINI

	select WATCHDOG_CORE

	help

	  Say Y here if to include support for the watchdog timer

	  embedded in the Cortina Systems Gemini family of devices.



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

	  module will be called gemini_wdt.



config IXP4XX_WATCHDOG

	tristate "IXP4xx Watchdog"

	depends on ARCH_IXP4XX

drivers/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -45,6 +45,7 @@ obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o 
obj-$(CONFIG_TWL4030_WATCHDOG) += twl4030_wdt.o

obj-$(CONFIG_21285_WATCHDOG) += wdt285.o

obj-$(CONFIG_977_WATCHDOG) += wdt977.o

obj-$(CONFIG_GEMINI_WATCHDOG) += gemini_wdt.o

obj-$(CONFIG_IXP4XX_WATCHDOG) += ixp4xx_wdt.o

obj-$(CONFIG_KS8695_WATCHDOG) += ks8695_wdt.o

obj-$(CONFIG_S3C2410_WATCHDOG) += s3c2410_wdt.o

drivers/watchdog/gemini_wdt.c

0 → 100644
+229 −0
Original line number Diff line number Diff line 
/*

 * Watchdog driver for Cortina Systems Gemini SoC

 *

 * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>

 *

 * Inspired by the out-of-tree drivers from OpenWRT:

 * Copyright (C) 2009 Paulius Zaleckas <paulius.zaleckas@teltonika.lt>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation.

 */



#include <linux/bitops.h>

#include <linux/init.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/kernel.h>

#include <linux/module.h>

#include <linux/of_device.h>

#include <linux/platform_device.h>

#include <linux/slab.h>

#include <linux/watchdog.h>



#define GEMINI_WDCOUNTER	0x0

#define GEMINI_WDLOAD		0x4

#define GEMINI_WDRESTART	0x8

#define GEMINI_WDCR		0xC



#define WDRESTART_MAGIC		0x5AB9



#define WDCR_CLOCK_5MHZ		BIT(4)

#define WDCR_SYS_RST		BIT(1)

#define WDCR_ENABLE		BIT(0)



#define WDT_CLOCK		5000000		/* 5 MHz */



struct gemini_wdt {

	struct watchdog_device	wdd;

	struct device		*dev;

	void __iomem		*base;

};



static inline

struct gemini_wdt *to_gemini_wdt(struct watchdog_device *wdd)

{

	return container_of(wdd, struct gemini_wdt, wdd);

}



static int gemini_wdt_start(struct watchdog_device *wdd)

{

	struct gemini_wdt *gwdt = to_gemini_wdt(wdd);



	writel(wdd->timeout * WDT_CLOCK, gwdt->base + GEMINI_WDLOAD);

	writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);

	/* set clock before enabling */

	writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST,

			gwdt->base + GEMINI_WDCR);

	writel(WDCR_CLOCK_5MHZ | WDCR_SYS_RST | WDCR_ENABLE,

			gwdt->base + GEMINI_WDCR);



	return 0;

}



static int gemini_wdt_stop(struct watchdog_device *wdd)

{

	struct gemini_wdt *gwdt = to_gemini_wdt(wdd);



	writel(0, gwdt->base + GEMINI_WDCR);



	return 0;

}



static int gemini_wdt_ping(struct watchdog_device *wdd)

{

	struct gemini_wdt *gwdt = to_gemini_wdt(wdd);



	writel(WDRESTART_MAGIC, gwdt->base + GEMINI_WDRESTART);



	return 0;

}



static int gemini_wdt_set_timeout(struct watchdog_device *wdd,

				  unsigned int timeout)

{

	wdd->timeout = timeout;

	if (watchdog_active(wdd))

		gemini_wdt_start(wdd);



	return 0;

}



static irqreturn_t gemini_wdt_interrupt(int irq, void *data)

{

	struct gemini_wdt *gwdt = data;



	watchdog_notify_pretimeout(&gwdt->wdd);



	return IRQ_HANDLED;

}



static const struct watchdog_ops gemini_wdt_ops = {

	.start		= gemini_wdt_start,

	.stop		= gemini_wdt_stop,

	.ping		= gemini_wdt_ping,

	.set_timeout	= gemini_wdt_set_timeout,

	.owner		= THIS_MODULE,

};



static const struct watchdog_info gemini_wdt_info = {

	.options	= WDIOF_KEEPALIVEPING

			| WDIOF_MAGICCLOSE

			| WDIOF_SETTIMEOUT,

	.identity	= KBUILD_MODNAME,

};





static int gemini_wdt_probe(struct platform_device *pdev)

{

	struct device *dev = &pdev->dev;

	struct resource *res;

	struct gemini_wdt *gwdt;

	unsigned int reg;

	int irq;

	int ret;



	gwdt = devm_kzalloc(dev, sizeof(*gwdt), GFP_KERNEL);

	if (!gwdt)

		return -ENOMEM;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	gwdt->base = devm_ioremap_resource(dev, res);

	if (IS_ERR(gwdt->base))

		return PTR_ERR(gwdt->base);



	irq = platform_get_irq(pdev, 0);

	if (!irq)

		return -EINVAL;



	gwdt->dev = dev;

	gwdt->wdd.info = &gemini_wdt_info;

	gwdt->wdd.ops = &gemini_wdt_ops;

	gwdt->wdd.min_timeout = 1;

	gwdt->wdd.max_timeout = 0xFFFFFFFF / WDT_CLOCK;

	gwdt->wdd.parent = dev;



	/*

	 * If 'timeout-sec' unspecified in devicetree, assume a 13 second

	 * default.

	 */

	gwdt->wdd.timeout = 13U;

	watchdog_init_timeout(&gwdt->wdd, 0, dev);



	reg = readw(gwdt->base + GEMINI_WDCR);

	if (reg & WDCR_ENABLE) {

		/* Watchdog was enabled by the bootloader, disable it. */

		reg &= ~WDCR_ENABLE;

		writel(reg, gwdt->base + GEMINI_WDCR);

	}



	ret = devm_request_irq(dev, irq, gemini_wdt_interrupt, 0,

			       "watchdog bark", gwdt);

	if (ret)

		return ret;



	ret = devm_watchdog_register_device(dev, &gwdt->wdd);

	if (ret) {

		dev_err(&pdev->dev, "failed to register watchdog\n");

		return ret;

	}



	/* Set up platform driver data */

	platform_set_drvdata(pdev, gwdt);

	dev_info(dev, "Gemini watchdog driver enabled\n");



	return 0;

}



static int __maybe_unused gemini_wdt_suspend(struct device *dev)

{

	struct gemini_wdt *gwdt = dev_get_drvdata(dev);

	unsigned int reg;



	reg = readw(gwdt->base + GEMINI_WDCR);

	reg &= ~WDCR_ENABLE;

	writel(reg, gwdt->base + GEMINI_WDCR);



	return 0;

}



static int __maybe_unused gemini_wdt_resume(struct device *dev)

{

	struct gemini_wdt *gwdt = dev_get_drvdata(dev);

	unsigned int reg;



	if (watchdog_active(&gwdt->wdd)) {

		reg = readw(gwdt->base + GEMINI_WDCR);

		reg |= WDCR_ENABLE;

		writel(reg, gwdt->base + GEMINI_WDCR);

	}



	return 0;

}



static const struct dev_pm_ops gemini_wdt_dev_pm_ops = {

	SET_SYSTEM_SLEEP_PM_OPS(gemini_wdt_suspend,

				gemini_wdt_resume)

};



#ifdef CONFIG_OF

static const struct of_device_id gemini_wdt_match[] = {

	{ .compatible = "cortina,gemini-watchdog" },

	{},

};

MODULE_DEVICE_TABLE(of, gemini_wdt_match);

#endif



static struct platform_driver gemini_wdt_driver = {

	.probe		= gemini_wdt_probe,

	.driver		= {

		.name	= "gemini-wdt",

		.of_match_table = of_match_ptr(gemini_wdt_match),

		.pm = &gemini_wdt_dev_pm_ops,

	},

};

module_platform_driver(gemini_wdt_driver);

MODULE_AUTHOR("Linus Walleij");

MODULE_DESCRIPTION("Watchdog driver for Gemini");

MODULE_LICENSE("GPL");

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