linux-kernel - [PATCH] watchdog: qcom: Remove incorrect usage of QCOM_WDT_ENABLE

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Message-Id: <20210126150241.10009-1-saiprakash.ranjan@codeaurora.org>
Date:   Tue, 26 Jan 2021 20:32:41 +0530
From:   Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
To:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Wim Van Sebroeck <wim@...ux-watchdog.org>,
        linux-watchdog@...r.kernel.org,
        Jorge Ramirez-Ortiz <jorge.ramirez-ortiz@...aro.org>,
        jorge@...ndries.io
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org,
        Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>,
        stable@...r.kernel.org
Subject: [PATCH] watchdog: qcom: Remove incorrect usage of QCOM_WDT_ENABLE_IRQ

As per register documentation, QCOM_WDT_ENABLE_IRQ which is BIT(1)
of watchdog control register is wakeup interrupt enable bit and
not related to bark interrupt at all, BIT(0) is used for that.
So remove incorrect usage of this bit when supporting bark irq for
pre-timeout notification. Currently with this bit set and bark
interrupt specified, pre-timeout notification and/or watchdog
reset/bite does not occur.

Fixes: 36375491a439 ("watchdog: qcom: support pre-timeout when the bark irq is available")
Cc: stable@...r.kernel.org
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@...eaurora.org>
---

Reading the conversations from when qcom pre-timeout support was
added [1], Bjorn already had mentioned it was not right to touch this
bit, not sure which SoC the pre-timeout was tested on at that time,
but I have tested this on SDM845, SM8150, SC7180 and watchdog bark
and bite does not occur with enabling this bit with the bark irq
specified in DT.

[1] https://lore.kernel.org/linux-watchdog/20190906174009.GC11938@tuxbook-pro/

---
 drivers/watchdog/qcom-wdt.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/drivers/watchdog/qcom-wdt.c b/drivers/watchdog/qcom-wdt.c
index 7cf0f2ec649b..e38a87ffe5f5 100644
--- a/drivers/watchdog/qcom-wdt.c
+++ b/drivers/watchdog/qcom-wdt.c
@@ -22,7 +22,6 @@ enum wdt_reg {
 };
 
 #define QCOM_WDT_ENABLE		BIT(0)
-#define QCOM_WDT_ENABLE_IRQ	BIT(1)
 
 static const u32 reg_offset_data_apcs_tmr[] = {
 	[WDT_RST] = 0x38,
@@ -63,16 +62,6 @@ struct qcom_wdt *to_qcom_wdt(struct watchdog_device *wdd)
 	return container_of(wdd, struct qcom_wdt, wdd);
 }
 
-static inline int qcom_get_enable(struct watchdog_device *wdd)
-{
-	int enable = QCOM_WDT_ENABLE;
-
-	if (wdd->pretimeout)
-		enable |= QCOM_WDT_ENABLE_IRQ;
-
-	return enable;
-}
-
 static irqreturn_t qcom_wdt_isr(int irq, void *arg)
 {
 	struct watchdog_device *wdd = arg;
@@ -91,7 +80,7 @@ static int qcom_wdt_start(struct watchdog_device *wdd)
 	writel(1, wdt_addr(wdt, WDT_RST));
 	writel(bark * wdt->rate, wdt_addr(wdt, WDT_BARK_TIME));
 	writel(wdd->timeout * wdt->rate, wdt_addr(wdt, WDT_BITE_TIME));
-	writel(qcom_get_enable(wdd), wdt_addr(wdt, WDT_EN));
+	writel(QCOM_WDT_ENABLE, wdt_addr(wdt, WDT_EN));
 	return 0;
 }
 
-- 
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