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Subject: Re: [PATCH v1 4/4] watchdog: npcm: sets card ext1 and ext2 bootstatus
 during probe
To:     Tomer Maimon <tmaimon77@gmail.com>, wim@linux-watchdog.org,
        robh+dt@kernel.org, mark.rutland@arm.com, joel@jms.id.au,
        avifishman70@gmail.com, tali.perry1@gmail.com, yuenn@google.com,
        benjaminfair@google.com
Cc:     linux-watchdog@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, openbmc@lists.ozlabs.org
References: <20200301094040.123189-1-tmaimon77@gmail.com>
 <20200301094040.123189-5-tmaimon77@gmail.com>
From:   Guenter Roeck <linux@roeck-us.net>
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Message-ID: <026fa94c-8fde-acda-e218-ffff9b5891c9@roeck-us.net>
Date:   Sun, 1 Mar 2020 02:48:08 -0800
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Sender: linux-kernel-owner@vger.kernel.org
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On 3/1/20 1:40 AM, Tomer Maimon wrote:
> During probe NPCM watchdog sets the following bootstatus flags:
> 	- WDIOF_CARDRESET represent power and core reset.
> 	- WDIOF_EXTERN1 represent watchdog 0-2 reset.
> 	- WDIOF_EXTERN2 represent software 1-4 reset.
> 
> Each flag is representing a group of bootstatus.
> The user can configure through the device treethe exact reset
> to each flag group.
> 

Sorry, this doesn't make sense to me. I could understand reporting
the above, but it looks to me like devicetree is used to associate
a reset bit from the controller with one of the above.
Devicetree only seems to be used to associate reset status bits
from the controller with WDIOF_CARDRESET, WDIOF_EXTERN1, or
WDIOF_EXTERN2. That adds a lot of complexity for little if any
gain.

It would make sense to set the bootstatus bits as suggested above,
but that doesn't require devicetree properties.

More comments inline.

Guenter

> Signed-off-by: Tomer Maimon <tmaimon77@gmail.com>
> ---
>  drivers/watchdog/npcm_wdt.c | 132 ++++++++++++++++++++++++++++++++----
>  1 file changed, 119 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/watchdog/npcm_wdt.c b/drivers/watchdog/npcm_wdt.c
> index 8609c7acf17d..dba9a73249c9 100644
> --- a/drivers/watchdog/npcm_wdt.c
> +++ b/drivers/watchdog/npcm_wdt.c
> @@ -11,7 +11,24 @@
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/watchdog.h>
> -
> +#include <linux/regmap.h>
> +#include <linux/mfd/syscon.h>
> +
New include files in alphabetic order merged with existing ones, please.

> +/* NPCM7xx GCR module */
> +#define NPCM7XX_RESSR_OFFSET		0x6C
> +#define NPCM7XX_INTCR2_OFFSET		0x60
> +
> +#define NPCM7XX_PORST			BIT(31)
> +#define NPCM7XX_CORST			BIT(30)
> +#define NPCM7XX_WD0RST			BIT(29)
> +#define NPCM7XX_WD1RST			BIT(24)
> +#define NPCM7XX_WD2RST			BIT(23)
> +#define NPCM7XX_SWR1RST			BIT(28)
> +#define NPCM7XX_SWR2RST			BIT(27)
> +#define NPCM7XX_SWR3RST			BIT(26)
> +#define NPCM7XX_SWR4RST			BIT(25)
> +
> + /* WD register */
>  #define NPCM_WTCR	0x1C
>  
>  #define NPCM_WTCLK	(BIT(10) | BIT(11))	/* Clock divider */
> @@ -43,6 +60,9 @@
>  struct npcm_wdt {
>  	struct watchdog_device  wdd;
>  	void __iomem		*reg;
> +	u32			card_reset;
> +	u32			ext1_reset;
> +	u32			ext2_reset;
>  };
>  
>  static inline struct npcm_wdt *to_npcm_wdt(struct watchdog_device *wdd)
> @@ -103,30 +123,29 @@ static int npcm_wdt_stop(struct watchdog_device *wdd)
>  	return 0;
>  }
>  
> -
>  static int npcm_wdt_set_timeout(struct watchdog_device *wdd,
>  				unsigned int timeout)
>  {
>  	if (timeout < 2)
>  		wdd->timeout = 1;
>  	else if (timeout < 3)
> -	      wdd->timeout = 2;
> +		wdd->timeout = 2;
>  	else if (timeout < 6)
> -	      wdd->timeout = 5;
> +		wdd->timeout = 5;
>  	else if (timeout < 11)
> -	      wdd->timeout = 10;
> +		wdd->timeout = 10;
>  	else if (timeout < 22)
> -	      wdd->timeout = 21;
> +		wdd->timeout = 21;
>  	else if (timeout < 44)
> -	      wdd->timeout = 43;
> +		wdd->timeout = 43;
>  	else if (timeout < 87)
> -	      wdd->timeout = 86;
> +		wdd->timeout = 86;
>  	else if (timeout < 173)
> -	      wdd->timeout = 172;
> +		wdd->timeout = 172;
>  	else if (timeout < 688)
> -	      wdd->timeout = 687;
> +		wdd->timeout = 687;
>  	else
> -	      wdd->timeout = 2750;
> +		wdd->timeout = 2750;
>  

Whitespace changes in a separate patch, please.

>  	if (watchdog_active(wdd))
>  		npcm_wdt_start(wdd);
> @@ -177,9 +196,61 @@ static const struct watchdog_ops npcm_wdt_ops = {
>  	.restart = npcm_wdt_restart,
>  };
>  
> +static void npcm_get_reset_status(struct npcm_wdt *wdt, struct device *dev)
> +{
> +	struct regmap *gcr_regmap;
> +	u32 rstval;
> +
> +	if (of_device_is_compatible(dev->of_node, "nuvoton,npcm750-wdt")) {
> +		gcr_regmap = syscon_regmap_lookup_by_compatible("nuvoton,npcm750-gcr");
> +		if (IS_ERR(gcr_regmap))
> +			dev_warn(dev, "Failed to find nuvoton,npcm750-gcr WD reset status not supported\n");
> +
> +		regmap_read(gcr_regmap, NPCM7XX_RESSR_OFFSET, &rstval);
> +		if (!rstval) {
> +			regmap_read(gcr_regmap, NPCM7XX_INTCR2_OFFSET, &rstval);
> +			rstval = ~rstval;
> +		}

The second register reports the same as the first only negated if
bits in the first register are not set ? That seems unlikely.
Please point to the datasheet, or at least provide a reference to the
two registers.

> +
> +		if (rstval & wdt->card_reset)
> +			wdt->wdd.bootstatus |= WDIOF_CARDRESET;
> +		if (rstval & wdt->ext1_reset)
> +			wdt->wdd.bootstatus |= WDIOF_EXTERN1;
> +		if (rstval & wdt->ext2_reset)
> +			wdt->wdd.bootstatus |= WDIOF_EXTERN2;
> +	}
> +}
> +
> +static u32 npcm_wdt_reset_type(const char *reset_type)
> +{
> +	if (!strcmp(reset_type, "porst"))
> +		return NPCM7XX_PORST;
> +	else if (!strcmp(reset_type, "corst"))
> +		return NPCM7XX_CORST;
> +	else if (!strcmp(reset_type, "wd0"))
> +		return NPCM7XX_WD0RST;
> +	else if (!strcmp(reset_type, "wd1"))
> +		return NPCM7XX_WD1RST;
> +	else if (!strcmp(reset_type, "wd2"))
> +		return NPCM7XX_WD2RST;
> +	else if (!strcmp(reset_type, "sw1"))
> +		return NPCM7XX_SWR1RST;
> +	else if (!strcmp(reset_type, "sw2"))
> +		return NPCM7XX_SWR2RST;
> +	else if (!strcmp(reset_type, "sw3"))
> +		return NPCM7XX_SWR3RST;
> +	else if (!strcmp(reset_type, "sw4"))
> +		return NPCM7XX_SWR4RST;
> +
> +	return 0;
> +}
> +
>  static int npcm_wdt_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> +	const char *card_reset_type;
> +	const char *ext1_reset_type;
> +	const char *ext2_reset_type;
>  	struct npcm_wdt *wdt;
>  	u32 priority;
>  	int irq;
> @@ -202,6 +273,39 @@ static int npcm_wdt_probe(struct platform_device *pdev)
>  	else
>  		watchdog_set_restart_priority(&wdt->wdd, priority);
>  
> +	ret = of_property_read_string(pdev->dev.of_node,
> +				      "nuvoton,card-reset-type",
> +				      &card_reset_type);
> +	if (ret) {
> +		wdt->card_reset = NPCM7XX_PORST;
> +	} else {
> +		wdt->card_reset = npcm_wdt_reset_type(card_reset_type);
> +		if (!wdt->card_reset)
> +			wdt->card_reset = NPCM7XX_PORST;
> +	}
> +
> +	ret = of_property_read_string(pdev->dev.of_node,
> +				      "nuvoton,ext1-reset-type",
> +				      &ext1_reset_type);
> +	if (ret) {
> +		wdt->ext1_reset = NPCM7XX_WD0RST;
> +	} else {
> +		wdt->ext1_reset = npcm_wdt_reset_type(ext1_reset_type);
> +		if (!wdt->ext1_reset)
> +			wdt->ext1_reset = NPCM7XX_WD0RST;
> +	}
> +
> +	ret = of_property_read_string(pdev->dev.of_node,
> +				      "nuvoton,ext2-reset-type",
> +				      &ext2_reset_type);
> +	if (ret) {
> +		wdt->ext2_reset = NPCM7XX_SWR1RST;
> +	} else {
> +		wdt->ext2_reset = npcm_wdt_reset_type(ext2_reset_type);
> +		if (!wdt->ext2_reset)
> +			wdt->ext2_reset = NPCM7XX_SWR1RST;
> +	}
> +
>  	wdt->wdd.info = &npcm_wdt_info;
>  	wdt->wdd.ops = &npcm_wdt_ops;
>  	wdt->wdd.min_timeout = 1;
> @@ -220,8 +324,10 @@ static int npcm_wdt_probe(struct platform_device *pdev)
>  		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
>  	}
>  
> -	ret = devm_request_irq(dev, irq, npcm_wdt_interrupt, 0, "watchdog",
> -			       wdt);
> +	npcm_get_reset_status(wdt, dev);
> +
> +	ret = devm_request_irq(dev, irq, npcm_wdt_interrupt, 0,
> +			       "watchdog", wdt);
>  	if (ret)
>  		return ret;
>  
>