[PATCH v6 14/20] watchdog: s3c2410_wdt: Add support for WTCON register DBGACK_MASK bit

Peter Griffin
2023-12-09T23:31:37Z

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@google.com>
Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org>
Signed-off-by: Peter Griffin <peter.griffin@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@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)
+#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