Message-ID: <000001d2e10a$5eaf8750$1c0e95f0$@socionext.com>
Date:   Fri, 9 Jun 2017 19:22:59 +0900
From:   "Keiji Hayashibara" <hayashibara.keiji@...ionext.com>
To:     "'Guenter Roeck'" <linux@...ck-us.net>, <wim@...ana.be>
Cc:     <linux-watchdog@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <robh+dt@...nel.org>, <devicetree@...r.kernel.org>,
        <masami.hiramatsu@...aro.org>, <jaswinder.singh@...aro.org>,
        Yamada, Masahiro/山田 真弘 
        <yamada.masahiro@...ionext.com>,
        Hayashi, Kunihiko/林 邦彦 
        <hayashi.kunihiko@...ionext.com>,
        Owada, Kiyoshi/大和田 清志 
        <owada.kiyoshi@...ionext.com>
Subject: RE: [PATCH V2 2/3] watchdog: uniphier: add UniPhier watchdog driver

Hi Guenter,

Thank you for your comment.

> On 06/06/2017 02:11 AM, Keiji Hayashibara wrote:
> > Add a watchdog driver for Socionext UniPhier series SoC.
> > Note that the timeout value for this device must be a power
> > of 2 because of the specification.
> >
> > Signed-off-by: Keiji Hayashibara <hayashibara.keiji@...ionext.com>
> > ---
> >   Documentation/watchdog/watchdog-parameters.txt |   6 +
> >   drivers/watchdog/Kconfig                       |  11 +
> >   drivers/watchdog/Makefile                      |   1 +
> >   drivers/watchdog/uniphier_wdt.c                | 275 +++++++++++++++++++++++++
> >   4 files changed, 293 insertions(+)
> >   create mode 100644 drivers/watchdog/uniphier_wdt.c
> >
> > diff --git a/Documentation/watchdog/watchdog-parameters.txt b/Documentation/watchdog/watchdog-parameters.txt
> > index 4f7d86d..6f9d7b4 100644
> > --- a/Documentation/watchdog/watchdog-parameters.txt
> > +++ b/Documentation/watchdog/watchdog-parameters.txt
> > @@ -369,6 +369,12 @@ timeout: Watchdog timeout in seconds. (0<timeout<N, default=60)
> >   nowayout: Watchdog cannot be stopped once started
> >   	(default=kernel config parameter)
> >   -------------------------------------------------
> > +uniphier_wdt:
> > +timeout: Watchdog timeout in power of two seconds.
> > +	(1 <= timeout <= 128, default=64)
> > +nowayout: Watchdog cannot be stopped once started
> > +	(default=kernel config parameter)
> > +-------------------------------------------------
> >   w83627hf_wdt:
> >   wdt_io: w83627hf/thf WDT io port (default 0x2E)
> >   timeout: Watchdog timeout in seconds. 1 <= timeout <= 255, default=60.
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
> > index 52a70ee..2a9d9a6 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -744,6 +744,17 @@ config ZX2967_WATCHDOG
> >   	  To compile this driver as a module, choose M here: the
> >   	  module will be called zx2967_wdt.
> >
> > +config UNIPHIER_WATCHDOG
> > +	tristate "UniPhier watchdog support"
> > +	depends on ARCH_UNIPHIER || COMPILE_TEST
> > +	select WATCHDOG_CORE
> > +	help
> > +	  Say Y here to include support watchdog timer embedded
> > +	  into the UniPhier system.
> > +
> > +	  To compile this driver as a module, choose M here: the
> > +	  module will be called uniphier_wdt.
> > +
> >   # AVR32 Architecture
> >
> >   config AT32AP700X_WDT
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index a2126e2..0928dac 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -84,6 +84,7 @@ obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o
> >   obj-$(CONFIG_RENESAS_WDT) += renesas_wdt.o
> >   obj-$(CONFIG_ASPEED_WATCHDOG) += aspeed_wdt.o
> >   obj-$(CONFIG_ZX2967_WATCHDOG) += zx2967_wdt.o
> > +obj-$(CONFIG_UNIPHIER_WATCHDOG) += uniphier_wdt.o
> >
> >   # AVR32 Architecture
> >   obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
> > diff --git a/drivers/watchdog/uniphier_wdt.c b/drivers/watchdog/uniphier_wdt.c
> > new file mode 100644
> > index 0000000..75862a0
> > --- /dev/null
> > +++ b/drivers/watchdog/uniphier_wdt.c
> > @@ -0,0 +1,275 @@
> > +/*
> > + * Watchdog driver for the UniPhier watchdog timer
> > + *
> > + * (c) Copyright 2014 Panasonic Corporation
> > + * (c) Copyright 2016 Socionext Inc.
> > + * All rights reserved.
> > + *
> > + * 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.
> > + *
> > + * This program is distributed in the hope that it will be useful,
> > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
> > +#include <linux/of.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/regmap.h>
> > +#include <linux/watchdog.h>
> > +#include <linux/bitops.h>
> > +
> > +/* WDT timer setting register */
> > +#define WDTTIMSET			0x3004
> > +#define   WDTTIMSET_PERIOD_MASK		(0xf << 0)
> > +#define   WDTTIMSET_PERIOD_1_SEC	(0x3 << 0)
> > +#define   WDTTIMSET_PERIOD_2_SEC	(0x4 << 0)
> > +#define   WDTTIMSET_PERIOD_4_SEC	(0x5 << 0)
> > +#define   WDTTIMSET_PERIOD_8_SEC	(0x6 << 0)
> > +#define   WDTTIMSET_PERIOD_16_SEC	(0x7 << 0)
> > +#define   WDTTIMSET_PERIOD_32_SEC	(0x8 << 0)
> > +#define   WDTTIMSET_PERIOD_64_SEC	(0x9 << 0)
> > +#define   WDTTIMSET_PERIOD_128_SEC	(0xa << 0)
> > +
> > +/* WDT reset selection register */
> > +#define WDTRSTSEL			0x3008
> > +#define   WDTRSTSEL_RSTSEL_MASK		(0x3 << 0)
> > +#define   WDTRSTSEL_RSTSEL_BOTH		(0x0 << 0)
> > +#define   WDTRSTSEL_RSTSEL_IRQ_ONLY	(0x2 << 0)
> > +
> > +/* WDT control register */
> > +#define WDTCTRL				0x300c
> > +#define   WDTCTRL_STATUS		BIT(8)
> > +#define   WDTCTRL_CLEAR			BIT(1)
> > +#define   WDTCTRL_ENABLE		BIT(0)
> > +
> > +#define SEC_TO_WDTTIMSET_PRD(sec) \
> > +		(ilog2(sec) + WDTTIMSET_PERIOD_1_SEC)
> > +
> > +#define WDTST_TIMEOUT			1000 /* usec */
> > +
> > +#define WDT_DEFAULT_TIMEOUT		64   /* Default is 64 seconds */
> > +#define WDT_PERIOD_MIN			1
> > +#define WDT_PERIOD_MAX			128
> > +
> > +static unsigned int timeout = WDT_DEFAULT_TIMEOUT;
> 
> This should be initialized to 0 (see below).

OK. I fix it.

> > +static bool nowayout = WATCHDOG_NOWAYOUT;
> > +
> > +struct uniphier_wdt_dev {
> > +	struct watchdog_device wdt_dev;
> > +	struct regmap	*regmap;
> > +};
> > +
> > +/*
> > + * UniPhier Watchdog operations
> > + */
> > +static int uniphier_watchdog_ping(struct watchdog_device *w)
> > +{
> > +	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	/* Clear counter */
> > +	ret = regmap_write_bits(wdev->regmap, WDTCTRL,
> > +				WDTCTRL_CLEAR, WDTCTRL_CLEAR);
> > +	if (!ret)
> > +		/*
> > +		 * As SoC specification, after clear counter,
> > +		 * it needs to wait until counter status is 1.
> > +		 */
> > +		ret = regmap_read_poll_timeout(wdev->regmap, WDTCTRL, val,
> > +					       (val & WDTCTRL_STATUS),
> > +					       0, WDTST_TIMEOUT);
> > +
> > +	return ret;
> > +}
> > +
> > +static int __uniphier_watchdog_start(struct regmap *regmap, unsigned int sec)
> > +{
> > +	unsigned int val;
> > +	int ret;
> > +
> > +	ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
> > +				       !(val & WDTCTRL_STATUS),
> > +				       0, WDTST_TIMEOUT);
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Setup period */
> > +	ret = regmap_write(regmap, WDTTIMSET,
> > +			   SEC_TO_WDTTIMSET_PRD(sec));
> > +	if (ret)
> > +		return ret;
> > +
> > +	/* Enable and clear watchdog */
> > +	ret = regmap_write(regmap, WDTCTRL, WDTCTRL_ENABLE | WDTCTRL_CLEAR);
> > +	if (!ret)
> > +		/*
> > +		 * As SoC specification, after clear counter,
> > +		 * it needs to wait until counter status is 1.
> > +		 */
> > +		ret = regmap_read_poll_timeout(regmap, WDTCTRL, val,
> > +					       (val & WDTCTRL_STATUS),
> > +					       0, WDTST_TIMEOUT);
> > +
> > +	return ret;
> > +}
> > +
> > +static int __uniphier_watchdog_stop(struct regmap *regmap)
> > +{
> > +	/* Disable and stop watchdog */
> > +	return regmap_write_bits(regmap, WDTCTRL, WDTCTRL_ENABLE, 0);
> > +}
> > +
> > +static int __uniphier_watchdog_restart(struct regmap *regmap, unsigned int sec)
> > +{
> > +	int ret;
> > +
> > +	ret = __uniphier_watchdog_stop(regmap);
> > +	if (ret)
> > +		return ret;
> > +
> > +	return __uniphier_watchdog_start(regmap, sec);
> > +}
> > +
> > +static int uniphier_watchdog_start(struct watchdog_device *w)
> > +{
> > +	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
> > +	unsigned int tmp_timeout;
> > +
> > +	tmp_timeout = roundup_pow_of_two(w->timeout);
> > +
> > +	return __uniphier_watchdog_start(wdev->regmap, tmp_timeout);
> > +}
> > +
> > +static int uniphier_watchdog_stop(struct watchdog_device *w)
> > +{
> > +	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
> > +
> > +	return __uniphier_watchdog_stop(wdev->regmap);
> > +}
> > +
> > +static int uniphier_watchdog_set_timeout(struct watchdog_device *w,
> > +					 unsigned int t)
> > +{
> > +	struct uniphier_wdt_dev *wdev = watchdog_get_drvdata(w);
> > +	unsigned int tmp_timeout;
> > +	int ret;
> > +
> > +	tmp_timeout = roundup_pow_of_two(t);
> > +	if (tmp_timeout == w->timeout)
> > +		return 0;
> > +
> > +	if (watchdog_active(w)) {
> > +		ret = __uniphier_watchdog_restart(wdev->regmap, tmp_timeout);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> > +	w->timeout = tmp_timeout;
> > +
> > +	return 0;
> > +}
> > +
> > +/*
> > + * Kernel Interfaces
> > + */
> > +static const struct watchdog_info uniphier_wdt_info = {
> > +	.identity	= "uniphier-wdt",
> > +	.options	= WDIOF_SETTIMEOUT |
> > +			  WDIOF_KEEPALIVEPING |
> > +			  WDIOF_MAGICCLOSE |
> > +			  WDIOF_OVERHEAT,
> > +};
> > +
> > +static const struct watchdog_ops uniphier_wdt_ops = {
> > +	.owner		= THIS_MODULE,
> > +	.start		= uniphier_watchdog_start,
> > +	.stop		= uniphier_watchdog_stop,
> > +	.ping		= uniphier_watchdog_ping,
> > +	.set_timeout	= uniphier_watchdog_set_timeout,
> > +};
> > +
> > +static int uniphier_wdt_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct uniphier_wdt_dev *wdev;
> > +	struct regmap *regmap;
> > +	struct device_node *parent;
> > +	int ret;
> > +
> > +	wdev = devm_kzalloc(dev, sizeof(*wdev), GFP_KERNEL);
> > +	if (!wdev)
> > +		return -ENOMEM;
> > +
> > +	platform_set_drvdata(pdev, wdev);
> > +
> > +	parent = of_get_parent(dev->of_node); /* parent should be syscon node */
> > +	regmap = syscon_node_to_regmap(parent);
> > +	of_node_put(parent);
> > +	if (IS_ERR(regmap))
> > +		return PTR_ERR(regmap);
> > +
> > +	wdev->regmap = regmap;
> > +	wdev->wdt_dev.info = &uniphier_wdt_info;
> > +	wdev->wdt_dev.ops = &uniphier_wdt_ops;
> > +	wdev->wdt_dev.timeout = WDT_DEFAULT_TIMEOUT;
> > +	wdev->wdt_dev.max_timeout = WDT_PERIOD_MAX;
> > +	wdev->wdt_dev.min_timeout = WDT_PERIOD_MIN;
> > +	wdev->wdt_dev.parent = dev;
> > +
> > +	watchdog_init_timeout(&wdev->wdt_dev, timeout, dev);
> 
> This only really makes sense if the default for 'timeout' is 0.
> Otherwise it will never take a timeout from devicetree unless timeout is
> explicitly set to 0 as module parameter, which does not make much sense.

It is certainly so.
I will fix it in next v3 patch.


> > +	watchdog_set_nowayout(&wdev->wdt_dev, nowayout);
> > +	watchdog_stop_on_reboot(&wdev->wdt_dev);
> > +
> > +	watchdog_set_drvdata(&wdev->wdt_dev, wdev);
> > +
> > +	uniphier_watchdog_stop(&wdev->wdt_dev);
> > +	ret = regmap_write(wdev->regmap, WDTRSTSEL, WDTRSTSEL_RSTSEL_BOTH);
> > +	if (ret)
> > +		return ret;
> > +
> > +	ret = devm_watchdog_register_device(dev, &wdev->wdt_dev);
> > +	if (ret)
> > +		return ret;
> > +
> > +	dev_info(dev, "watchdog driver (timeout=%d sec, nowayout=%d)\n",
> > +		 wdev->wdt_dev.timeout, nowayout);
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id uniphier_wdt_dt_ids[] = {
> > +	{ .compatible = "socionext,uniphier-wdt" },
> > +	{ /* sentinel */ }
> > +};
> > +MODULE_DEVICE_TABLE(of, uniphier_wdt_dt_ids);
> > +
> > +static struct platform_driver uniphier_wdt_driver = {
> > +	.probe		= uniphier_wdt_probe,
> > +	.driver		= {
> > +		.name		= "uniphier-wdt",
> > +		.of_match_table	= uniphier_wdt_dt_ids,
> > +	},
> > +};
> > +
> > +module_platform_driver(uniphier_wdt_driver);
> > +
> > +module_param(timeout, uint, 0000);
> > +MODULE_PARM_DESC(timeout,
> > +	"Watchdog timeout seconds in power of 2. (0 < timeout < 128, default="
> > +				__MODULE_STRING(WDT_DEFAULT_TIMEOUT) ")");
> > +
> > +module_param(nowayout, bool, 0000);
> > +MODULE_PARM_DESC(nowayout,
> > +	"Watchdog cannot be stopped once started (default="
> > +				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
> > +
> > +MODULE_AUTHOR("Socionext Inc.");
> > +MODULE_DESCRIPTION("UniPhier Watchdog Device Driver");
> > +MODULE_LICENSE("GPL v2");
> >
> 
> The license here does not match the license in the header (which states GPL2+).

I will modify in next v3 patch.

----------
Best Regards,
Keiji Hayashibara

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