[PATCH 5.4 278/453] watchdog: sprd: check busy bit before new loading rather than after that

[Greg Kroah-Hartman]

From: Lingling Xu <ling_ling.xu@xxxxxxxxxx>

[ Upstream commit 3e07d240939803bed9feb2a353d94686a411a7ca ]

As the specification described, users must check busy bit before start
a new loading operation to make sure that the previous loading is done
and the device is ready to accept a new one.

[ chunyan: Massaged changelog ]

Fixes: 477603467009 ("watchdog: Add Spreadtrum watchdog driver")
Signed-off-by: Lingling Xu <ling_ling.xu@xxxxxxxxxx>
Signed-off-by: Chunyan Zhang <chunyan.zhang@xxxxxxxxxx>
Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20201029023933.24548-3-zhang.lyra@xxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/watchdog/sprd_wdt.c | 25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
index f3c90b4afead1..b9b1daa9e2a4c 100644
--- a/drivers/watchdog/sprd_wdt.c
+++ b/drivers/watchdog/sprd_wdt.c
@@ -108,18 +108,6 @@ static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
 	u32 tmr_step = timeout * SPRD_WDT_CNT_STEP;
 	u32 prtmr_step = pretimeout * SPRD_WDT_CNT_STEP;
 
-	sprd_wdt_unlock(wdt->base);
-	writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
-		      SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
-	writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
-		       wdt->base + SPRD_WDT_LOAD_LOW);
-	writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
-			SPRD_WDT_LOW_VALUE_MASK,
-		       wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
-	writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
-		       wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
-	sprd_wdt_lock(wdt->base);
-
 	/*
 	 * Waiting the load value operation done,
 	 * it needs two or three RTC clock cycles.
@@ -134,6 +122,19 @@ static int sprd_wdt_load_value(struct sprd_wdt *wdt, u32 timeout,
 
 	if (delay_cnt >= SPRD_WDT_LOAD_TIMEOUT)
 		return -EBUSY;
+
+	sprd_wdt_unlock(wdt->base);
+	writel_relaxed((tmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
+		      SPRD_WDT_LOW_VALUE_MASK, wdt->base + SPRD_WDT_LOAD_HIGH);
+	writel_relaxed((tmr_step & SPRD_WDT_LOW_VALUE_MASK),
+		       wdt->base + SPRD_WDT_LOAD_LOW);
+	writel_relaxed((prtmr_step >> SPRD_WDT_CNT_HIGH_SHIFT) &
+			SPRD_WDT_LOW_VALUE_MASK,
+		       wdt->base + SPRD_WDT_IRQ_LOAD_HIGH);
+	writel_relaxed(prtmr_step & SPRD_WDT_LOW_VALUE_MASK,
+		       wdt->base + SPRD_WDT_IRQ_LOAD_LOW);
+	sprd_wdt_lock(wdt->base);
+
 	return 0;
 }
 
-- 
2.27.0