clocksource/drivers/sprd: Enable register for timer counter from 32 bit to 64 bit

Using 32 bit for suspend compensation, the max compensation time is 36
hours(working clock is 32k).In some IOT devices, the suspend time may
be long, even exceeding 36 hours. Therefore, a 64 bit timer counter
is needed for counting.

Signed-off-by: Enlin Mu <enlin.mu@unisoc.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Link: https://patch.msgid.link/20251106021830.34846-1-enlin.mu@linux.dev

Author: muenlin

drivers/clocksource/timer-sprd.c

@@ -30,6 +30,7 @@
 #define TIMER_VALUE_SHDW_HI	0x1c
 
 #define TIMER_VALUE_LO_MASK	GENMASK(31, 0)
+#define TIMER_VALUE_HI_MASK	GENMASK(31, 0)
 
 static void sprd_timer_enable(void __iomem *base, u32 flag)
 {
@@ -162,15 +163,26 @@ static struct timer_of suspend_to = {
 
 static u64 sprd_suspend_timer_read(struct clocksource *cs)
 {
-	return ~(u64)readl_relaxed(timer_of_base(&suspend_to) +
-				   TIMER_VALUE_SHDW_LO) & cs->mask;
+	u32 lo, hi;
+
+	do {
+		hi = readl_relaxed(timer_of_base(&suspend_to) +
+				   TIMER_VALUE_SHDW_HI);
+		lo = readl_relaxed(timer_of_base(&suspend_to) +
+				   TIMER_VALUE_SHDW_LO);
+	} while (hi != readl_relaxed(timer_of_base(&suspend_to) + TIMER_VALUE_SHDW_HI));
+
+	return ~(((u64)hi << 32) | lo);
 }
 
 static int sprd_suspend_timer_enable(struct clocksource *cs)
 {
-	sprd_timer_update_counter(timer_of_base(&suspend_to),
-				  TIMER_VALUE_LO_MASK);
-	sprd_timer_enable(timer_of_base(&suspend_to), TIMER_CTL_PERIOD_MODE);
+	writel_relaxed(TIMER_VALUE_LO_MASK,
+		       timer_of_base(&suspend_to) + TIMER_LOAD_LO);
+	writel_relaxed(TIMER_VALUE_HI_MASK,
+		       timer_of_base(&suspend_to) + TIMER_LOAD_HI);
+	sprd_timer_enable(timer_of_base(&suspend_to),
+			  TIMER_CTL_PERIOD_MODE|TIMER_CTL_64BIT_WIDTH);
 
 	return 0;
 }
@@ -186,7 +198,7 @@ static struct clocksource suspend_clocksource = {
 	.read	= sprd_suspend_timer_read,
 	.enable = sprd_suspend_timer_enable,
 	.disable = sprd_suspend_timer_disable,
-	.mask	= CLOCKSOURCE_MASK(32),
+	.mask	= CLOCKSOURCE_MASK(64),
 	.flags	= CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_SUSPEND_NONSTOP,
 };