[PATCH v7 10/16] watchdog: s3c2410_wdt: Add support for WTCON register DBGACK_MASK bit

[Alim Akhtar]

Hi Peter

> -----Original Message-----
> From: Peter Griffin <peter.griffin at linaro.org>
> Sent: Monday, December 11, 2023 9:53 PM
> To: robh+dt at kernel.org; krzysztof.kozlowski+dt at linaro.org;
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> wim at linux-watchdog.org; linux at roeck-us.net; catalin.marinas at arm.com;
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> Cc: peter.griffin at linaro.org; tudor.ambarus at linaro.org;
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> Subject: [PATCH v7 10/16] watchdog: s3c2410_wdt: Add support for WTCON
> register DBGACK_MASK bit
> 
> The WDT uses the CPU core signal DBGACK to determine whether the SoC is
> running in debug mode or not. If the DBGACK signal is asserted and
> DBGACK_MASK bit is enabled, then WDT output and interrupt is masked
> (disabled).
> 
> Presence of the DBGACK_MASK bit is determined by adding a new
> QUIRK_HAS_DBGACK_BIT quirk. Also update to use BIT macro to avoid
> checkpatch --strict warnings.
> 
> Tested-by: Will McVicker <willmcvicker at google.com>
> Reviewed-by: Sam Protsenko <semen.protsenko at linaro.org>
> Signed-off-by: Peter Griffin <peter.griffin at linaro.org>
> ---
>  drivers/watchdog/s3c2410_wdt.c | 28 +++++++++++++++++++++++++---
>  1 file changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/watchdog/s3c2410_wdt.c
> b/drivers/watchdog/s3c2410_wdt.c index 0b4bd883ff28..7ecb762a371d
> 100644
> --- a/drivers/watchdog/s3c2410_wdt.c
> +++ b/drivers/watchdog/s3c2410_wdt.c
> @@ -9,6 +9,7 @@
>   *     (c) Copyright 1996 Alan Cox <alan at lxorguk.ukuu.org.uk>
>   */
> 
> +#include <linux/bits.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
>  #include <linux/types.h>
> @@ -34,9 +35,10 @@
> 
>  #define S3C2410_WTCNT_MAXCNT	0xffff
> 
> -#define S3C2410_WTCON_RSTEN	(1 << 0)
> -#define S3C2410_WTCON_INTEN	(1 << 2)
> -#define S3C2410_WTCON_ENABLE	(1 << 5)
> +#define S3C2410_WTCON_RSTEN		BIT(0)
> +#define S3C2410_WTCON_INTEN		BIT(2)
> +#define S3C2410_WTCON_ENABLE		BIT(5)
> +#define S3C2410_WTCON_DBGACK_MASK	BIT(16)
> 
>  #define S3C2410_WTCON_DIV16	(0 << 3)
>  #define S3C2410_WTCON_DIV32	(1 << 3)
> @@ -100,12 +102,17 @@
>   * %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.
> + *
> + * %QUIRK_HAS_DBGACK_BIT: WTCON register has DBGACK_MASK bit.
> Setting
> + the
> + * DBGACK_MASK bit disables the watchdog outputs when the SoC is in
> debug mode.
> + * Debug mode is determined by the DBGACK CPU signal.
>   */
>  #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)
Probably these above defines might also give checkpatch --strict warnings,
so you can change to use  BIT macro here as well.

> +#define QUIRK_HAS_DBGACK_BIT			BIT(5)
> 
>  /* These quirks require that we have a PMU register map */  #define
> QUIRKS_HAVE_PMUREG \ @@ -375,6 +382,19 @@ static int
> s3c2410wdt_enable(struct s3c2410_wdt *wdt, bool en)
>  	return 0;
>  }
> 
> +/* Disable watchdog outputs if CPU is in debug mode */ static void
> +s3c2410wdt_mask_dbgack(struct s3c2410_wdt *wdt) {
> +	unsigned long wtcon;
> +
> +	if (!(wdt->drv_data->quirks & QUIRK_HAS_DBGACK_BIT))
> +		return;
> +
> +	wtcon = readl(wdt->reg_base + S3C2410_WTCON);
> +	wtcon |= S3C2410_WTCON_DBGACK_MASK;
> +	writel(wtcon, wdt->reg_base + S3C2410_WTCON); }
> +
>  static int s3c2410wdt_keepalive(struct watchdog_device *wdd)  {
>  	struct s3c2410_wdt *wdt = watchdog_get_drvdata(wdd); @@ -700,6
> +720,8 @@ static int s3c2410wdt_probe(struct platform_device *pdev)
>  	wdt->wdt_device.bootstatus = s3c2410wdt_get_bootstatus(wdt);
>  	wdt->wdt_device.parent = dev;
> 
> +	s3c2410wdt_mask_dbgack(wdt);
> +
>  	/*
>  	 * If "tmr_atboot" param is non-zero, start the watchdog right now.
> Also
>  	 * set WDOG_HW_RUNNING bit, so that watchdog core can kick the
> watchdog.
> --
> 2.43.0.472.g3155946c3a-goog