linux-kernel - Re: [PATCH v3 12/12] watchdog: s3c2410: Add Exynos850 support

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Message-ID: <2c0e5b23-92c5-70c9-3460-e9748f8a869e@roeck-us.net>
Date:   Sat, 20 Nov 2021 12:29:36 -0800
From:   Guenter Roeck <linux@...ck-us.net>
To:     Sam Protsenko <semen.protsenko@...aro.org>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Cc:     linux-watchdog@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v3 12/12] watchdog: s3c2410: Add Exynos850 support

On 11/7/21 12:29 PM, Sam Protsenko wrote:
> Exynos850 is a bit different from SoCs already supported in WDT driver:
>    - AUTOMATIC_WDT_RESET_DISABLE register is removed, so its value is
>      always 0; .disable_auto_reset callback is not set for that reason
>    - MASK_WDT_RESET_REQUEST register is replaced with
>      CLUSTERx_NONCPU_IN_EN register; instead of masking (disabling) WDT
>      reset interrupt it's now enabled with the same value; .mask_reset
>      callback is reused for that functionality though
>    - To make WDT functional, WDT counter needs to be enabled in
>      CLUSTERx_NONCPU_OUT register; it's done using .enable_counter
>      callback
> 
> Also Exynos850 has two CPU clusters, each has its own dedicated WDT
> instance. Different PMU registers and bits are used for each cluster. So
> driver data is now modified in probe, adding needed info depending on
> cluster index passed from device tree.
> 
> Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
> ---
> Changes in v3:
>    - Renamed "samsung,index" property to more descriptive
>      "samsung,cluster-index"
>    - Used pre-defined and completely set driver data for cluster0 and
>      cluster1
> 
> Changes in v2:
>    - Used single compatible for Exynos850, populating missing driver data
>      in probe
>    - Added "index" property to specify CPU cluster index
> 
>   drivers/watchdog/s3c2410_wdt.c | 62 +++++++++++++++++++++++++++++++++-
>   1 file changed, 61 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index 96aa5d9c6ed4..1456201f27de 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -56,6 +56,13 @@
>   #define EXYNOS5_RST_STAT_REG_OFFSET		0x0404
>   #define EXYNOS5_WDT_DISABLE_REG_OFFSET		0x0408
>   #define EXYNOS5_WDT_MASK_RESET_REG_OFFSET	0x040c
> +#define EXYNOS850_CLUSTER0_NONCPU_OUT		0x1220
> +#define EXYNOS850_CLUSTER0_NONCPU_INT_EN	0x1244
> +#define EXYNOS850_CLUSTER1_NONCPU_OUT		0x1620
> +#define EXYNOS850_CLUSTER1_NONCPU_INT_EN	0x1644
> +
> +#define EXYNOS850_CLUSTER0_WDTRESET_BIT		24
> +#define EXYNOS850_CLUSTER1_WDTRESET_BIT		23
>   
>   /**
>    * Quirk flags for different Samsung watchdog IP-cores.
> @@ -205,6 +212,30 @@ static const struct s3c2410_wdt_variant drv_data_exynos7 = {
>   		  QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
>   };
>   
> +static const struct s3c2410_wdt_variant drv_data_exynos850_cl0 = {
> +	.mask_reset_reg = EXYNOS850_CLUSTER0_NONCPU_INT_EN,
> +	.mask_bit = 2,
> +	.mask_reset_inv = true,
> +	.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> +	.rst_stat_bit = EXYNOS850_CLUSTER0_WDTRESET_BIT,
> +	.cnt_en_reg = EXYNOS850_CLUSTER0_NONCPU_OUT,
> +	.cnt_en_bit = 7,
> +	.quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> +		  QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_CNT_EN,
> +};
> +
> +static const struct s3c2410_wdt_variant drv_data_exynos850_cl1 = {
> +	.mask_reset_reg = EXYNOS850_CLUSTER1_NONCPU_INT_EN,
> +	.mask_bit = 2,
> +	.mask_reset_inv = true,
> +	.rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> +	.rst_stat_bit = EXYNOS850_CLUSTER1_WDTRESET_BIT,
> +	.cnt_en_reg = EXYNOS850_CLUSTER1_NONCPU_OUT,
> +	.cnt_en_bit = 7,
> +	.quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> +		  QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_CNT_EN,
> +};
> +
>   static const struct of_device_id s3c2410_wdt_match[] = {
>   	{ .compatible = "samsung,s3c2410-wdt",
>   	  .data = &drv_data_s3c2410 },
> @@ -216,6 +247,8 @@ static const struct of_device_id s3c2410_wdt_match[] = {
>   	  .data = &drv_data_exynos5420 },
>   	{ .compatible = "samsung,exynos7-wdt",
>   	  .data = &drv_data_exynos7 },
> +	{ .compatible = "samsung,exynos850-wdt",
> +	  .data = &drv_data_exynos850_cl0 },
>   	{},
>   };
>   MODULE_DEVICE_TABLE(of, s3c2410_wdt_match);
> @@ -587,14 +620,38 @@ static inline const struct s3c2410_wdt_variant *
>   s3c2410_get_wdt_drv_data(struct platform_device *pdev)
>   {
>   	const struct s3c2410_wdt_variant *variant;
> +	struct device *dev = &pdev->dev;
>   
> -	variant = of_device_get_match_data(&pdev->dev);
> +	variant = of_device_get_match_data(dev);
>   	if (!variant) {
>   		/* Device matched by platform_device_id */
>   		variant = (struct s3c2410_wdt_variant *)
>   			   platform_get_device_id(pdev)->driver_data;
>   	}
>   
> +	/* Choose Exynos850 driver data w.r.t. cluster index */
> +	if (variant == &drv_data_exynos850_cl0) {

0-day has a point here. drv_data_exynos850_cl0 is declared inside a CONFIG_OF
conditional, causing compile failure if CONFIG_OF is not enabled.

Please fix and resubmit.

Guenter