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/andes_plmt_timer.c

@@ -18,11 +18,30 @@
 /* mtime register */
 #define MTIME_REG(base)			((ulong)(base))
 
-static u64 andes_plmt_get_count(struct udevice *dev)
+static u64 notrace andes_plmt_get_count(struct udevice *dev)
 {
 	return readq((void __iomem *)MTIME_REG(dev_get_priv(dev)));
 }
 
+#if CONFIG_IS_ENABLED(RISCV_MMODE) && 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_MMODE_TIMER_FREQ;
+}
+
+/**
+ * timer_early_get_count() - Get the timer count before driver model
+ *
+ */
+u64 notrace timer_early_get_count(void)
+{
+	return readq((void __iomem *)MTIME_REG(RISCV_MMODE_TIMERBASE));
+}
+#endif
+
 static const struct timer_ops andes_plmt_ops = {
 	.get_count = andes_plmt_get_count,
 };

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);

drivers/timer/sifive_clint_timer.c

@@ -15,11 +15,30 @@
 /* mtime register */
 #define MTIME_REG(base)			((ulong)(base) + 0xbff8)
 
-static u64 sifive_clint_get_count(struct udevice *dev)
+static u64 notrace sifive_clint_get_count(struct udevice *dev)
 {
 	return readq((void __iomem *)MTIME_REG(dev_get_priv(dev)));
 }
 
+#if CONFIG_IS_ENABLED(RISCV_MMODE) && 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_MMODE_TIMER_FREQ;
+}
+
+/**
+ * timer_early_get_count() - Get the timer count before driver model
+ *
+ */
+u64 notrace timer_early_get_count(void)
+{
+	return readq((void __iomem *)MTIME_REG(RISCV_MMODE_TIMERBASE));
+}
+#endif
+
 static const struct timer_ops sifive_clint_ops = {
 	.get_count = sifive_clint_get_count,
 };

include/configs/ax25-ae350.h

@@ -17,6 +17,11 @@
 #endif
 #endif
 
+#define RISCV_MMODE_TIMERBASE           0xe6000000
+#define RISCV_MMODE_TIMER_FREQ          60000000
+
+#define RISCV_SMODE_TIMER_FREQ          60000000
+
 /*
  * CPU and Board Configuration Options
  */

include/configs/qemu-riscv.h

@@ -29,6 +29,11 @@
 
 #define CONFIG_STANDALONE_LOAD_ADDR	0x80200000
 
+#define RISCV_MMODE_TIMERBASE		0x2000000
+#define RISCV_MMODE_TIMER_FREQ		1000000
+
+#define RISCV_SMODE_TIMER_FREQ		1000000
+
 /* Environment options */
 
 #ifndef CONFIG_SPL_BUILD

include/configs/sifive-fu540.h

@@ -36,6 +36,11 @@
 
 #define CONFIG_STANDALONE_LOAD_ADDR	0x80200000
 
+#define RISCV_MMODE_TIMERBASE		0x2000000
+#define RISCV_MMODE_TIMER_FREQ		1000000
+
+#define RISCV_SMODE_TIMER_FREQ		1000000
+
 /* Environment options */
 
 #ifndef CONFIG_SPL_BUILD