watchdog: sprd: check busy bit before new loading rather than after that

[ 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@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20201029023933.24548-3-zhang.lyra@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/watchdog/sprd_wdt.c b/drivers/watchdog/sprd_wdt.c
index f3c90b4..b9b1daa 100644 (file)
--- 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;
 }