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Message-ID: <20211117133639.GI2435591@roeck-us.net>
Date: Wed, 17 Nov 2021 05:36:39 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Sam Protsenko <semen.protsenko@...aro.org>
Cc: Wim Van Sebroeck <wim@...ux-watchdog.org>,
Rob Herring <robh+dt@...nel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>,
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 09/12] watchdog: s3c2410: Cleanup PMU related code
On Sun, Nov 07, 2021 at 10:29:40PM +0200, Sam Protsenko wrote:
> Now that PMU enablement code was extended for new Exynos SoCs, it
> doesn't look very cohesive and consistent anymore. Do a bit of renaming,
> grouping and style changes, to make it look good again. While at it, add
> quirks documentation as well.
>
> No functional change, just a refactoring commit.
>
> Signed-off-by: Sam Protsenko <semen.protsenko@...aro.org>
> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> Changes in v3:
> - Added quirks documentation
> - Added R-b tag by Krzysztof Kozlowski
>
> Changes in v2:
> - (none): it's a new patch
>
> drivers/watchdog/s3c2410_wdt.c | 83 ++++++++++++++++++++++++----------
> 1 file changed, 58 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c
> index ec341c876225..f211be8bf976 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -56,17 +56,51 @@
> #define EXYNOS5_RST_STAT_REG_OFFSET 0x0404
> #define EXYNOS5_WDT_DISABLE_REG_OFFSET 0x0408
> #define EXYNOS5_WDT_MASK_RESET_REG_OFFSET 0x040c
> -#define QUIRK_HAS_PMU_CONFIG (1 << 0)
> -#define QUIRK_HAS_RST_STAT (1 << 1)
> -#define QUIRK_HAS_WTCLRINT_REG (1 << 2)
> +
> +/**
> + * Quirk flags for different Samsung watchdog IP-cores.
> + *
> + * This driver supports multiple Samsung SoCs, each of which might have
> + * different set of registers and features supported. As watchdog block
> + * sometimes requires modifying PMU registers for proper functioning, register
> + * differences in both watchdog and PMU IP-cores should be accounted for. Quirk
> + * flags described below serve the purpose of telling the driver about mentioned
> + * SoC traits, and can be specified in driver data for each particular supported
> + * device.
> + *
> + * %QUIRK_HAS_WTCLRINT_REG: Watchdog block has WTCLRINT register. It's used to
> + * clear the interrupt once the interrupt service routine is complete. It's
> + * write-only, writing any values to this register clears the interrupt, but
> + * reading is not permitted.
> + *
> + * %QUIRK_HAS_PMU_MASK_RESET: PMU block has the register for disabling/enabling
> + * WDT reset request. On old SoCs it's usually called MASK_WDT_RESET_REQUEST,
> + * new SoCs have CLUSTERx_NONCPU_INT_EN register, which 'mask_bit' value is
> + * inverted compared to the former one.
> + *
> + * %QUIRK_HAS_PMU_RST_STAT: PMU block has RST_STAT (reset status) register,
> + * which contains bits indicating the reason for most recent CPU reset. If
> + * present, driver will use this register to check if previous reboot was due to
> + * watchdog timer reset.
> + *
> + * %QUIRK_HAS_PMU_AUTO_DISABLE: PMU block has AUTOMATIC_WDT_RESET_DISABLE
> + * register. If 'mask_bit' bit is set, PMU will disable WDT reset when
> + * corresponding processor is in reset state.
> + *
> + * %QUIRK_HAS_PMU_CNT_EN: PMU block has some register (e.g. CLUSTERx_NONCPU_OUT)
> + * with "watchdog counter enable" bit. That bit should be set to make watchdog
> + * counter running.
> + */
> +#define QUIRK_HAS_WTCLRINT_REG (1 << 0)
> +#define QUIRK_HAS_PMU_MASK_RESET (1 << 1)
> +#define QUIRK_HAS_PMU_RST_STAT (1 << 2)
> #define QUIRK_HAS_PMU_AUTO_DISABLE (1 << 3)
> #define QUIRK_HAS_PMU_CNT_EN (1 << 4)
>
> /* These quirks require that we have a PMU register map */
> -#define QUIRKS_HAVE_PMUREG (QUIRK_HAS_PMU_CONFIG | \
> - QUIRK_HAS_RST_STAT | \
> - QUIRK_HAS_PMU_AUTO_DISABLE | \
> - QUIRK_HAS_PMU_CNT_EN)
> +#define QUIRKS_HAVE_PMUREG \
> + (QUIRK_HAS_PMU_MASK_RESET | QUIRK_HAS_PMU_RST_STAT | \
> + QUIRK_HAS_PMU_AUTO_DISABLE | QUIRK_HAS_PMU_CNT_EN)
>
> static bool nowayout = WATCHDOG_NOWAYOUT;
> static int tmr_margin;
> @@ -146,8 +180,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos5250 = {
> .mask_bit = 20,
> .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> .rst_stat_bit = 20,
> - .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
> - | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
> + .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> + QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
> };
>
> static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
> @@ -156,8 +190,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos5420 = {
> .mask_bit = 0,
> .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> .rst_stat_bit = 9,
> - .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
> - | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
> + .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> + QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
> };
>
> static const struct s3c2410_wdt_variant drv_data_exynos7 = {
> @@ -166,8 +200,8 @@ static const struct s3c2410_wdt_variant drv_data_exynos7 = {
> .mask_bit = 23,
> .rst_stat_reg = EXYNOS5_RST_STAT_REG_OFFSET,
> .rst_stat_bit = 23, /* A57 WDTRESET */
> - .quirks = QUIRK_HAS_PMU_CONFIG | QUIRK_HAS_RST_STAT \
> - | QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_AUTO_DISABLE,
> + .quirks = QUIRK_HAS_WTCLRINT_REG | QUIRK_HAS_PMU_MASK_RESET | \
> + QUIRK_HAS_PMU_RST_STAT | QUIRK_HAS_PMU_AUTO_DISABLE,
> };
>
> static const struct of_device_id s3c2410_wdt_match[] = {
> @@ -253,24 +287,24 @@ static int s3c2410wdt_enable_counter(struct s3c2410_wdt *wdt, bool en)
> return ret;
> }
>
> -static int s3c2410wdt_mask_and_disable_reset(struct s3c2410_wdt *wdt, bool mask)
> +static int s3c2410wdt_enable(struct s3c2410_wdt *wdt, bool en)
> {
> int ret;
>
> if (wdt->drv_data->quirks & QUIRK_HAS_PMU_AUTO_DISABLE) {
> - ret = s3c2410wdt_disable_wdt_reset(wdt, mask);
> + ret = s3c2410wdt_disable_wdt_reset(wdt, !en);
> if (ret < 0)
> return ret;
> }
>
> - if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CONFIG) {
> - ret = s3c2410wdt_mask_wdt_reset(wdt, mask);
> + if (wdt->drv_data->quirks & QUIRK_HAS_PMU_MASK_RESET) {
> + ret = s3c2410wdt_mask_wdt_reset(wdt, !en);
> if (ret < 0)
> return ret;
> }
>
> if (wdt->drv_data->quirks & QUIRK_HAS_PMU_CNT_EN) {
> - ret = s3c2410wdt_enable_counter(wdt, !mask);
> + ret = s3c2410wdt_enable_counter(wdt, en);
> if (ret < 0)
> return ret;
> }
> @@ -531,7 +565,7 @@ static inline unsigned int s3c2410wdt_get_bootstatus(struct s3c2410_wdt *wdt)
> unsigned int rst_stat;
> int ret;
>
> - if (!(wdt->drv_data->quirks & QUIRK_HAS_RST_STAT))
> + if (!(wdt->drv_data->quirks & QUIRK_HAS_PMU_RST_STAT))
> return 0;
>
> ret = regmap_read(wdt->pmureg, wdt->drv_data->rst_stat_reg, &rst_stat);
> @@ -672,7 +706,7 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
> if (ret)
> goto err_cpufreq;
>
> - ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
> + ret = s3c2410wdt_enable(wdt, true);
> if (ret < 0)
> goto err_unregister;
>
> @@ -707,7 +741,7 @@ static int s3c2410wdt_remove(struct platform_device *dev)
> int ret;
> struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
>
> - ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
> + ret = s3c2410wdt_enable(wdt, false);
> if (ret < 0)
> return ret;
>
> @@ -724,8 +758,7 @@ static void s3c2410wdt_shutdown(struct platform_device *dev)
> {
> struct s3c2410_wdt *wdt = platform_get_drvdata(dev);
>
> - s3c2410wdt_mask_and_disable_reset(wdt, true);
> -
> + s3c2410wdt_enable(wdt, false);
> s3c2410wdt_stop(&wdt->wdt_device);
> }
>
> @@ -740,7 +773,7 @@ static int s3c2410wdt_suspend(struct device *dev)
> wdt->wtcon_save = readl(wdt->reg_base + S3C2410_WTCON);
> wdt->wtdat_save = readl(wdt->reg_base + S3C2410_WTDAT);
>
> - ret = s3c2410wdt_mask_and_disable_reset(wdt, true);
> + ret = s3c2410wdt_enable(wdt, false);
> if (ret < 0)
> return ret;
>
> @@ -760,7 +793,7 @@ static int s3c2410wdt_resume(struct device *dev)
> writel(wdt->wtdat_save, wdt->reg_base + S3C2410_WTCNT);/* Reset count */
> writel(wdt->wtcon_save, wdt->reg_base + S3C2410_WTCON);
>
> - ret = s3c2410wdt_mask_and_disable_reset(wdt, false);
> + ret = s3c2410wdt_enable(wdt, true);
> if (ret < 0)
> return ret;
>
> --
> 2.30.2
>
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