dm: timer: Support 64-bit counter

There are timers with a 64-bit counter value but current timer
uclass driver assumes a 32-bit one. Modify timer_get_count()
to ask timer driver to always return a 64-bit counter value,
and provide an inline helper function timer_conv_64() to handle
the 32-bit/64-bit conversion automatically.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

drivers/timer/altera_timer.c

@@ -34,7 +34,7 @@ struct altera_timer_platdata {
 	struct altera_timer_regs *regs;
 };
 
-static int altera_timer_get_count(struct udevice *dev, unsigned long *count)
+static int altera_timer_get_count(struct udevice *dev, u64 *count)
 {
 	struct altera_timer_platdata *plat = dev->platdata;
 	struct altera_timer_regs *const regs = plat->regs;
@@ -46,7 +46,7 @@ static int altera_timer_get_count(struct udevice *dev, unsigned long *count)
 	/* Read timer value */
 	val = readl(&regs->snapl) & 0xffff;
 	val |= (readl(&regs->snaph) & 0xffff) << 16;
-	*count = ~val;
+	*count = timer_conv_64(~val);
 
 	return 0;
 }

drivers/timer/sandbox_timer.c

@@ -18,7 +18,7 @@ void sandbox_timer_add_offset(unsigned long offset)
 	sandbox_timer_offset += offset;
 }
 
-static int sandbox_timer_get_count(struct udevice *dev, unsigned long *count)
+static int sandbox_timer_get_count(struct udevice *dev, u64 *count)
 {
 	*count = os_get_nsec() / 1000 + sandbox_timer_offset * 1000;
 

drivers/timer/timer-uclass.c

@@ -13,14 +13,14 @@ DECLARE_GLOBAL_DATA_PTR;
 
 /*
  * Implement a timer uclass to work with lib/time.c. The timer is usually
- * a 32 bits free-running up counter. The get_rate() method is used to get
+ * a 32/64 bits free-running up counter. The get_rate() method is used to get
  * the input clock frequency of the timer. The get_count() method is used
- * to get the current 32 bits count value. If the hardware is counting down,
+ * to get the current 64 bits count value. If the hardware is counting down,
  * the value should be inversed inside the method. There may be no real
  * tick, and no timer interrupt.
  */
 
-int timer_get_count(struct udevice *dev, unsigned long *count)
+int timer_get_count(struct udevice *dev, u64 *count)
 {
 	const struct timer_ops *ops = device_get_ops(dev);
 
@@ -47,6 +47,15 @@ static int timer_pre_probe(struct udevice *dev)
 	return 0;
 }
 
+u64 timer_conv_64(u32 count)
+{
+	/* increment tbh if tbl has rolled over */
+	if (count < gd->timebase_l)
+		gd->timebase_h++;
+	gd->timebase_l = count;
+	return ((u64)gd->timebase_h << 32) | gd->timebase_l;
+}
+
 UCLASS_DRIVER(timer) = {
 	.id		= UCLASS_TIMER,
 	.name		= "timer",

include/timer.h

@@ -8,13 +8,21 @@
 #define _TIMER_H_
 
 /*
+ * timer_conv_64 - convert 32-bit counter value to 64-bit
+ *
+ * @count: 32-bit counter value
+ * @return: 64-bit counter value
+ */
+u64 timer_conv_64(u32 count);
+
+/*
  * Get the current timer count
  *
  * @dev: The timer device
  * @count: pointer that returns the current timer count
  * @return: 0 if OK, -ve on error
  */
-int timer_get_count(struct udevice *dev, unsigned long *count);
+int timer_get_count(struct udevice *dev, u64 *count);
 
 /*
  * Get the timer input clock frequency
@@ -35,10 +43,10 @@ struct timer_ops {
 	 * Get the current timer count
 	 *
 	 * @dev: The timer device
-	 * @count: pointer that returns the current timer count
+	 * @count: pointer that returns the current 64-bit timer count
 	 * @return: 0 if OK, -ve on error
 	 */
-	int (*get_count)(struct udevice *dev, unsigned long *count);
+	int (*get_count)(struct udevice *dev, u64 *count);
 };
 
 /*

lib/time.c

@@ -69,9 +69,9 @@ ulong notrace get_tbclk(void)
 	return timer_get_rate(gd->timer);
 }
 
-unsigned long notrace timer_read_counter(void)
+uint64_t notrace get_ticks(void)
 {
-	unsigned long count;
+	u64 count;
 	int ret;
 
 	ret = dm_timer_init();
@@ -84,7 +84,8 @@ unsigned long notrace timer_read_counter(void)
 
 	return count;
 }
-#endif /* CONFIG_TIMER */
+
+#else /* !CONFIG_TIMER */
 
 uint64_t __weak notrace get_ticks(void)
 {
@@ -97,6 +98,8 @@ uint64_t __weak notrace get_ticks(void)
 	return ((uint64_t)gd->timebase_h << 32) | gd->timebase_l;
 }
 
+#endif /* CONFIG_TIMER */
+
 /* Returns time in milliseconds */
 static uint64_t notrace tick_to_time(uint64_t tick)
 {