riscv: timer: Add support for an early timer

Added support for timer_early_get_count() and timer_early_get_rate()
This is mostly useful in tracing.

Signed-off-by: Pragnesh Patel <pragnesh.patel@sifive.com>
Reviewed-by: Rick Chen <rick@andestech.com>

drivers/timer/riscv_timer.c

@@ -16,7 +16,7 @@
 #include <timer.h>
 #include <asm/csr.h>
 
-static u64 riscv_timer_get_count(struct udevice *dev)
+static u64 notrace riscv_timer_get_count(struct udevice *dev)
 {
 	__maybe_unused u32 hi, lo;
 
@@ -31,6 +31,25 @@ static u64 riscv_timer_get_count(struct udevice *dev)
 	return ((u64)hi << 32) | lo;
 }
 
+#if CONFIG_IS_ENABLED(RISCV_SMODE) && IS_ENABLED(CONFIG_TIMER_EARLY)
+/**
+ * timer_early_get_rate() - Get the timer rate before driver model
+ */
+unsigned long notrace timer_early_get_rate(void)
+{
+	return RISCV_SMODE_TIMER_FREQ;
+}
+
+/**
+ * timer_early_get_count() - Get the timer count before driver model
+ *
+ */
+u64 notrace timer_early_get_count(void)
+{
+	return riscv_timer_get_count(NULL);
+}
+#endif
+
 static int riscv_timer_probe(struct udevice *dev)
 {
 	struct timer_dev_priv *uc_priv = dev_get_uclass_priv(dev);