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Commit ab3f09fe authored by John Crispin's avatar John Crispin Committed by Wim Van Sebroeck
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watchdog: add MT7621 watchdog support 



This patch adds support for the watchdog core found on newer MediaTek Wifi
SoCs MT7621 and MT7628. There is no symbol for MT7628 as it is a subtype of
MT7620 so we depend on that instead.

Signed-off-by: default avatarJohn Crispin <blogic@openwrt.org>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarWim Van Sebroeck <wim@iguana.be>
parent 3b8d058c

Documentation/devicetree/bindings/watchdog/mt7621-wdt.txt

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+12 −0
Original line number Diff line number Diff line 
Ralink Watchdog Timers



Required properties:

- compatible: must be "mediatek,mt7621-wdt"

- reg: physical base address of the controller and length of the register range



Example:



	watchdog@100 {

		compatible = "mediatek,mt7621-wdt";

		reg = <0x100 0x10>;

	};

drivers/watchdog/Kconfig

+7 −0
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@@ -1403,6 +1403,13 @@ config RALINK_WDT 
	help

	  Hardware driver for the Ralink SoC Watchdog Timer.



config MT7621_WDT

	tristate "Mediatek SoC watchdog"

	select WATCHDOG_CORE

	depends on SOC_MT7620 || SOC_MT7621

	help

	  Hardware driver for the Mediatek/Ralink MT7621/8 SoC Watchdog Timer.



# PARISC Architecture



# POWERPC Architecture

drivers/watchdog/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -152,6 +152,7 @@ octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o 
obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o

obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o

obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o

obj-$(CONFIG_MT7621_WDT) += mt7621_wdt.o



# PARISC Architecture

drivers/watchdog/mt7621_wdt.c

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/*

 * Ralink MT7621/MT7628 built-in hardware watchdog timer

 *

 * Copyright (C) 2014 John Crispin <blogic@openwrt.org>

 *

 * This driver was based on: drivers/watchdog/rt2880_wdt.c

 *

 * 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/clk.h>

#include <linux/reset.h>

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/watchdog.h>

#include <linux/moduleparam.h>

#include <linux/platform_device.h>



#include <asm/mach-ralink/ralink_regs.h>



#define SYSC_RSTSTAT			0x38

#define WDT_RST_CAUSE			BIT(1)



#define RALINK_WDT_TIMEOUT		30



#define TIMER_REG_TMRSTAT		0x00

#define TIMER_REG_TMR1LOAD		0x24

#define TIMER_REG_TMR1CTL		0x20



#define TMR1CTL_ENABLE			BIT(7)

#define TMR1CTL_RESTART			BIT(9)

#define TMR1CTL_PRESCALE_SHIFT		16



static void __iomem *mt7621_wdt_base;

static struct reset_control *mt7621_wdt_reset;



static bool nowayout = WATCHDOG_NOWAYOUT;

module_param(nowayout, bool, 0);

MODULE_PARM_DESC(nowayout,

		 "Watchdog cannot be stopped once started (default="

		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");



static inline void rt_wdt_w32(unsigned reg, u32 val)

{

	iowrite32(val, mt7621_wdt_base + reg);

}



static inline u32 rt_wdt_r32(unsigned reg)

{

	return ioread32(mt7621_wdt_base + reg);

}



static int mt7621_wdt_ping(struct watchdog_device *w)

{

	rt_wdt_w32(TIMER_REG_TMRSTAT, TMR1CTL_RESTART);



	return 0;

}



static int mt7621_wdt_set_timeout(struct watchdog_device *w, unsigned int t)

{

	w->timeout = t;

	rt_wdt_w32(TIMER_REG_TMR1LOAD, t * 1000);

	mt7621_wdt_ping(w);



	return 0;

}



static int mt7621_wdt_start(struct watchdog_device *w)

{

	u32 t;



	/* set the prescaler to 1ms == 1000us */

	rt_wdt_w32(TIMER_REG_TMR1CTL, 1000 << TMR1CTL_PRESCALE_SHIFT);



	mt7621_wdt_set_timeout(w, w->timeout);



	t = rt_wdt_r32(TIMER_REG_TMR1CTL);

	t |= TMR1CTL_ENABLE;

	rt_wdt_w32(TIMER_REG_TMR1CTL, t);



	return 0;

}



static int mt7621_wdt_stop(struct watchdog_device *w)

{

	u32 t;



	mt7621_wdt_ping(w);



	t = rt_wdt_r32(TIMER_REG_TMR1CTL);

	t &= ~TMR1CTL_ENABLE;

	rt_wdt_w32(TIMER_REG_TMR1CTL, t);



	return 0;

}



static int mt7621_wdt_bootcause(void)

{

	if (rt_sysc_r32(SYSC_RSTSTAT) & WDT_RST_CAUSE)

		return WDIOF_CARDRESET;



	return 0;

}



static struct watchdog_info mt7621_wdt_info = {

	.identity = "Mediatek Watchdog",

	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,

};



static struct watchdog_ops mt7621_wdt_ops = {

	.owner = THIS_MODULE,

	.start = mt7621_wdt_start,

	.stop = mt7621_wdt_stop,

	.ping = mt7621_wdt_ping,

	.set_timeout = mt7621_wdt_set_timeout,

};



static struct watchdog_device mt7621_wdt_dev = {

	.info = &mt7621_wdt_info,

	.ops = &mt7621_wdt_ops,

	.min_timeout = 1,

	.max_timeout = 0xfffful / 1000,

};



static int mt7621_wdt_probe(struct platform_device *pdev)

{

	struct resource *res;

	int ret;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	mt7621_wdt_base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(mt7621_wdt_base))

		return PTR_ERR(mt7621_wdt_base);



	mt7621_wdt_reset = devm_reset_control_get(&pdev->dev, NULL);

	if (!IS_ERR(mt7621_wdt_reset))

		reset_control_deassert(mt7621_wdt_reset);



	mt7621_wdt_dev.dev = &pdev->dev;

	mt7621_wdt_dev.bootstatus = mt7621_wdt_bootcause();



	watchdog_init_timeout(&mt7621_wdt_dev, mt7621_wdt_dev.max_timeout,

			      &pdev->dev);

	watchdog_set_nowayout(&mt7621_wdt_dev, nowayout);



	ret = watchdog_register_device(&mt7621_wdt_dev);



	return 0;

}



static int mt7621_wdt_remove(struct platform_device *pdev)

{

	watchdog_unregister_device(&mt7621_wdt_dev);



	return 0;

}



static void mt7621_wdt_shutdown(struct platform_device *pdev)

{

	mt7621_wdt_stop(&mt7621_wdt_dev);

}



static const struct of_device_id mt7621_wdt_match[] = {

	{ .compatible = "mediatek,mt7621-wdt" },

	{},

};

MODULE_DEVICE_TABLE(of, mt7621_wdt_match);



static struct platform_driver mt7621_wdt_driver = {

	.probe		= mt7621_wdt_probe,

	.remove		= mt7621_wdt_remove,

	.shutdown	= mt7621_wdt_shutdown,

	.driver		= {

		.name		= KBUILD_MODNAME,

		.of_match_table	= mt7621_wdt_match,

	},

};



module_platform_driver(mt7621_wdt_driver);



MODULE_DESCRIPTION("MediaTek MT762x hardware watchdog driver");

MODULE_AUTHOR("John Crispin <blogic@openwrt.org");

MODULE_LICENSE("GPL v2");