Date:   Fri, 14 Apr 2023 11:44:17 +0000
From:   Bharat Bhushan <bbhushan2@...vell.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        "wim@...ux-watchdog.org" <wim@...ux-watchdog.org>,
        "linux@...ck-us.net" <linux@...ck-us.net>,
        "robh+dt@...nel.org" <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>,
        "linux-watchdog@...r.kernel.org" <linux-watchdog@...r.kernel.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [EXT] Re: [PATCH 2/2] Watchdog: Add octeontx2 GTI watchdog driver

Please see inline 

> -----Original Message-----
> From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
> Sent: Friday, April 14, 2023 4:58 PM
> To: Bharat Bhushan <bbhushan2@...vell.com>; wim@...ux-watchdog.org;
> linux@...ck-us.net; robh+dt@...nel.org; krzysztof.kozlowski+dt@...aro.org;
> linux-watchdog@...r.kernel.org; devicetree@...r.kernel.org; linux-
> kernel@...r.kernel.org
> Subject: [EXT] Re: [PATCH 2/2] Watchdog: Add octeontx2 GTI watchdog driver
> 
> External Email
> 
> ----------------------------------------------------------------------
> On 14/04/2023 12:23, Bharat Bhushan wrote:
> > GTI watchdog timer are programmed in "interrupt + del3t + reset mode"
> > and del3t traps are not enabled.
> > GTI watchdog exception flow is:
> >  - 1st timer expiration generates watchdog interrupt.
> >  - 2nd timer expiration is ignored
> >  - On 3rd timer expiration will trigger a system-wide core reset.
> >
> > Signed-off-by: Bharat Bhushan <bbhushan2@...vell.com>
> > ---
> >  drivers/watchdog/Kconfig         |   9 ++
> >  drivers/watchdog/Makefile        |   1 +
> >  drivers/watchdog/octeontx2_wdt.c | 238
> > +++++++++++++++++++++++++++++++
> >  3 files changed, 248 insertions(+)
> >  create mode 100644 drivers/watchdog/octeontx2_wdt.c
> >
> > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig index
> > f0872970daf9..31ff282c62ad 100644
> > --- a/drivers/watchdog/Kconfig
> > +++ b/drivers/watchdog/Kconfig
> > @@ -2212,4 +2212,13 @@ config KEEMBAY_WATCHDOG
> >  	  To compile this driver as a module, choose M here: the
> >  	  module will be called keembay_wdt.
> >
> > +config OCTEONTX2_WATCHDOG
> > +	tristate "OCTEONTX2 Watchdog driver"
> > +	depends on ARCH_THUNDER || (COMPILE_TEST && 64BIT)
> 
> Why it cannot be compile tested on 32-bit?

Used in 64 bit configuration but no harm getting compile tested for 32bit.
Will change

> 
> > +	help
> > +	 OCTEONTX2 GTI hardware supports watchdog timer. This watchdog
> timer are
> > +	 programmed in "interrupt + del3t + reset" mode. On first expiry it will
> > +	 generate interrupt. Second expiry (del3t) is ignored and system will reset
> > +	 on final timer expiry.
> > +
> >  endif # WATCHDOG
> > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
> > index 9cbf6580f16c..aa1b813ad1f9 100644
> > --- a/drivers/watchdog/Makefile
> > +++ b/drivers/watchdog/Makefile
> > @@ -230,3 +230,4 @@ obj-$(CONFIG_MENZ069_WATCHDOG) +=
> menz69_wdt.o
> >  obj-$(CONFIG_RAVE_SP_WATCHDOG) += rave-sp-wdt.o
> >  obj-$(CONFIG_STPMIC1_WATCHDOG) += stpmic1_wdt.o
> >  obj-$(CONFIG_SL28CPLD_WATCHDOG) += sl28cpld_wdt.o
> > +obj-$(CONFIG_OCTEONTX2_WATCHDOG) += octeontx2_wdt.o
> 
> Please tell me that you added it in some reasonable place, not just at the end...
> The same in Kconfig.

Is it alphabetical order, any suggestion?

> 
> > diff --git a/drivers/watchdog/octeontx2_wdt.c
> > b/drivers/watchdog/octeontx2_wdt.c
> > new file mode 100644
> > index 000000000000..7b78a092e83f
> > --- /dev/null
> > +++ b/drivers/watchdog/octeontx2_wdt.c
> > @@ -0,0 +1,238 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Marvell Octeontx2 Watchdog driver
> > + *
> > + * Copyright (C) 2023 Marvell International Ltd.
> > + *
> > + * 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.
> 
> Drop boilerplate.
> 
> > + */
> > +
> > +#include <linux/module.h>
> > +#include <linux/cpu.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/watchdog.h>
> > +#include <linux/sched/debug.h>
> > +
> > +#include <asm/arch_timer.h>
> > +
> > +/* GTI CWD Watchdog Registers */
> > +#define GTI_CWD_GLOBAL_WDOG_IDX		63
> > +#define GTI_CWD_WDOG			(0x8 *
> GTI_CWD_GLOBAL_WDOG_IDX)
> > +#define GTI_CWD_WDOG_MODE_INT_DEL3T_RST	0x3
> > +#define GTI_CWD_WDOG_MODE_MASK		0x3
> > +#define GTI_CWD_WDOG_LEN_SHIFT		4
> > +#define GTI_CWD_WDOG_CNT_SHIFT		20
> > +
> > +/* GTI Per-core Watchdog Interrupt Register */
> > +#define GTI_CWD_INT			0x200
> > +#define GTI_CWD_INT_PENDING_STATUS	(1ULL <<
> GTI_CWD_GLOBAL_WDOG_IDX)
> > +
> > +/* GTI Per-core Watchdog Interrupt Enable Clear Register */
> > +#define GTI_CWD_INT_ENA_CLR		0x210
> > +#define GTI_CWD_INT_ENA_CLR_VAL		(1ULL <<
> GTI_CWD_GLOBAL_WDOG_IDX)
> > +
> > +/* GTI Per-core Watchdog Interrupt Enable Set Register */
> > +#define GTI_CWD_INT_ENA_SET		0x218
> > +#define GTI_CWD_INT_ENA_SET_VAL		(1ULL <<
> GTI_CWD_GLOBAL_WDOG_IDX)
> > +
> > +/* GTI Per-core Watchdog Poke Registers */
> > +#define GTI_CWD_POKE		(0x10000 + 0x8 *
> GTI_CWD_GLOBAL_WDOG_IDX)
> > +#define GTI_CWD_POKE_VAL	(1ULL << GTI_CWD_GLOBAL_WDOG_IDX)
> > +
> > +struct octeontx2_wdt_priv {
> > +	struct watchdog_device wdev;
> > +	void __iomem *base;
> > +	u64 clock_freq;
> > +	int irq;
> > +};
> > +
> > +static irqreturn_t octeontx2_wdt_interrupt(int irq, void *data) {
> > +	panic("Kernel Watchdog");
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +static int octeontx2_wdt_ping(struct watchdog_device *wdev) {
> > +	struct octeontx2_wdt_priv *priv = watchdog_get_drvdata(wdev);
> > +
> > +	writeq(GTI_CWD_POKE_VAL, priv->base + GTI_CWD_POKE);
> > +	return 0;
> > +}
> > +
> > +static int octeontx2_wdt_start(struct watchdog_device *wdev) {
> > +	struct octeontx2_wdt_priv *priv = watchdog_get_drvdata(wdev);
> > +	u64 regval;
> > +
> > +	set_bit(WDOG_HW_RUNNING, &wdev->status);
> > +
> > +	/* Clear any pending interrupt */
> > +	writeq(GTI_CWD_INT_PENDING_STATUS, priv->base + GTI_CWD_INT);
> > +
> > +	/* Enable Interrupt */
> > +	writeq(GTI_CWD_INT_ENA_SET_VAL, priv->base +
> GTI_CWD_INT_ENA_SET);
> > +
> > +	/* Set (Interrupt + SCP interrupt (DEL3T) + core domain reset) Mode */
> > +	regval = readq(priv->base + GTI_CWD_WDOG);
> > +	regval |= GTI_CWD_WDOG_MODE_INT_DEL3T_RST;
> > +	writeq(regval, priv->base + GTI_CWD_WDOG);
> > +
> > +	return 0;
> > +}
> > +
> > +static int octeontx2_wdt_stop(struct watchdog_device *wdev) {
> > +	struct octeontx2_wdt_priv *priv = watchdog_get_drvdata(wdev);
> > +	u64 regval;
> > +
> > +	/* Disable Interrupt */
> > +	writeq(GTI_CWD_INT_ENA_CLR_VAL, priv->base +
> GTI_CWD_INT_ENA_CLR);
> > +
> > +	/* Set GTI_CWD_WDOG.Mode = 0 to stop the timer */
> > +	regval = readq(priv->base + GTI_CWD_WDOG);
> > +	regval &= ~GTI_CWD_WDOG_MODE_MASK;
> > +	writeq(regval, priv->base + GTI_CWD_WDOG);
> > +
> > +	return 0;
> > +}
> > +
> > +static int octeontx2_wdt_settimeout(struct watchdog_device *wdev,
> > +					unsigned int timeout)
> > +{
> > +	struct octeontx2_wdt_priv *priv = watchdog_get_drvdata(wdev);
> > +	u64 timeout_wdog, regval;
> > +
> > +	/* Update new timeout */
> > +	wdev->timeout = timeout;
> > +
> > +	/* Get clock cycles from timeout in second */
> > +	timeout_wdog = (u64)timeout * priv->clock_freq;
> > +
> > +	/* Watchdog counts in 1024 cycle steps */
> > +	timeout_wdog = timeout_wdog >> 10;
> > +
> > +	/*
> > +	 * Hardware allows programming of upper 16-bits of 24-bits cycles
> > +	 * Round up and use upper 16-bits only.
> > +	 * Set max if timeout more than h/w supported
> > +	 */
> > +	timeout_wdog = (timeout_wdog + 0xff) >> 8;
> > +	if (timeout_wdog >= 0x10000)
> > +		timeout_wdog = 0xffff;
> > +
> > +	/*
> > +	 * GTI_CWD_WDOG.LEN have only upper 16-bits of 24-bits
> > +	 * GTI_CWD_WDOG.CNT, need addition shift of 8.
> > +	 */
> > +	regval = readq(priv->base + GTI_CWD_WDOG);
> > +	regval &= GTI_CWD_WDOG_MODE_MASK;
> > +	regval |= ((timeout_wdog) << (GTI_CWD_WDOG_CNT_SHIFT + 8)) |
> > +		   (timeout_wdog << GTI_CWD_WDOG_LEN_SHIFT);
> > +	writeq(regval, priv->base + GTI_CWD_WDOG);
> > +	return 0;
> > +}
> > +
> > +static const struct watchdog_info octeontx2_wdt_ident = {
> > +	.identity = "OcteonTX2 watchdog",
> > +	.options	= WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
> WDIOF_MAGICCLOSE |
> > +			  WDIOF_CARDRESET,
> 
> Weird indentation in =

Do not know how it comes in email, they are correctly aligned when look into code.

> 
> > +};
> > +
> > +static const struct watchdog_ops octeontx2_wdt_ops = {
> > +	.owner = THIS_MODULE,
> > +	.start = octeontx2_wdt_start,
> > +	.stop = octeontx2_wdt_stop,
> > +	.ping = octeontx2_wdt_ping,
> > +	.set_timeout = octeontx2_wdt_settimeout, };
> > +
> > +static int octeontx2_wdt_probe(struct platform_device *pdev) {
> > +	struct octeontx2_wdt_priv *priv;
> > +	struct device *dev = &pdev->dev;
> > +	struct watchdog_device *wdog_dev;
> > +	int irq;
> > +	int err;
> > +
> > +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> > +	if (!priv)
> > +		return -ENOMEM;
> > +
> > +	priv->base = devm_platform_ioremap_resource(pdev, 0);
> > +	if (IS_ERR(priv->base))
> > +		return dev_err_probe(&pdev->dev, PTR_ERR(priv->base),
> > +			      "reg property not valid/found\n");
> > +
> > +	priv->clock_freq = arch_timer_get_cntfrq();
> > +
> > +	wdog_dev = &priv->wdev;
> > +	wdog_dev->info = &octeontx2_wdt_ident,
> > +	wdog_dev->ops = &octeontx2_wdt_ops,
> > +	wdog_dev->parent = dev;
> > +	wdog_dev->min_timeout = 1;
> > +	wdog_dev->max_timeout = 16;
> > +	wdog_dev->max_hw_heartbeat_ms = 16000;
> > +	wdog_dev->timeout = 8;
> > +
> > +	irq = platform_get_irq(pdev, 0);
> > +	if (irq < 0) {
> > +		dev_err(&pdev->dev, "IRQ resource not found\n");
> 
> return dev_err_probe
> also in other places

okay

> 
> > +		return -ENODEV;
> > +	}
> > +
> > +	err = request_irq(irq, octeontx2_wdt_interrupt, 0, pdev->name, priv);
> > +	if (err) {
> > +		dev_err(dev, "cannot register interrupt handler %d\n", err);
> > +		return err;
> > +	}
> > +
> > +	priv->irq = irq;
> > +	watchdog_set_drvdata(wdog_dev, priv);
> > +	platform_set_drvdata(pdev, priv);
> > +	watchdog_init_timeout(wdog_dev, wdog_dev->timeout, dev);
> > +	octeontx2_wdt_settimeout(wdog_dev, wdog_dev->timeout);
> > +	watchdog_stop_on_reboot(wdog_dev);
> > +	watchdog_stop_on_unregister(wdog_dev);
> > +
> > +	err = devm_watchdog_register_device(dev, wdog_dev);
> > +	if (err) {
> > +		free_irq(irq, priv);
> > +		return err;
> > +	}
> > +
> > +	dev_info(dev, "Watchdog enabled (timeout=%d sec)\n", wdog_dev-
> >timeout);
> > +	return 0;
> > +}
> > +
> > +static int octeontx2_wdt_remove(struct platform_device *pdev) {
> > +	struct octeontx2_wdt_priv *priv = platform_get_drvdata(pdev);
> > +
> > +	if (priv->irq)
> 
> Is it possible?
> 
> > +		free_irq(priv->irq, priv);
> 
> Anyway, your order of cleanup is a bit surprising. It is expected to be reversed
> from probe. In probe() you requested IRQs before watchdog, but cleanup will be
> done before watchdog release? This does not look right.

Watchdog release happen outside this driver as we used devm_*. Will convert request_irq to devm_request_irq(). 

Thanks
-Bharat

> 
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct of_device_id octeontx2_wdt_of_match[] = {
> > +	{ .compatible = "marvell-octeontx2-wdt", },
> > +	{ },
> > +};
> > +MODULE_DEVICE_TABLE(of, octeontx2_wdt_of_match);
> 
> Best regards,
> Krzysztof

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