lib: sbi: Simplify timer platform operations

Instead of having timer_value(), timer_event_start(), and
timer_event_stop() callbacks in platform operations, it will
be much simpler for timer driver to directly register these
operations as device to the sbi_timer implementation.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>

lib/sbi/sbi_platform.c

@@ -19,9 +19,6 @@ static inline char *sbi_platform_feature_id2string(unsigned long feature)
 		return NULL;
 
 	switch (feature) {
-	case SBI_PLATFORM_HAS_TIMER_VALUE:
-		fstr = "timer";
-		break;
 	case SBI_PLATFORM_HAS_HART_HOTPLUG:
 		fstr = "hotplug";
 		break;

lib/sbi/sbi_timer.c

@@ -16,10 +16,11 @@
 #include <sbi/sbi_timer.h>
 
 static unsigned long time_delta_off;
-static u64 (*get_time_val)(const struct sbi_platform *plat);
+static u64 (*get_time_val)(void);
+static const struct sbi_timer_device *timer_dev = NULL;
 
 #if __riscv_xlen == 32
-static u64 get_ticks(const struct sbi_platform *plat)
+static u64 get_ticks(void)
 {
 	u32 lo, hi, tmp;
 	__asm__ __volatile__("1:\n"
@@ -31,7 +32,7 @@ static u64 get_ticks(const struct sbi_platform *plat)
 	return ((u64)hi << 32) | lo;
 }
 #else
-static u64 get_ticks(const struct sbi_platform *plat)
+static u64 get_ticks(void)
 {
 	unsigned long n;
 
@@ -40,9 +41,16 @@ static u64 get_ticks(const struct sbi_platform *plat)
 }
 #endif
 
+static u64 get_platform_ticks(void)
+{
+	return timer_dev->timer_value();
+}
+
 u64 sbi_timer_value(void)
 {
-	return get_time_val(sbi_platform_thishart_ptr());
+	if (get_time_val)
+		return get_time_val();
+	return 0;
 }
 
 u64 sbi_timer_virt_value(void)
@@ -80,7 +88,8 @@ void sbi_timer_set_delta_upper(ulong delta_upper)
 
 void sbi_timer_event_start(u64 next_event)
 {
-	sbi_platform_timer_event_start(sbi_platform_thishart_ptr(), next_event);
+	if (timer_dev && timer_dev->timer_event_start)
+		timer_dev->timer_event_start(next_event);
 	csr_clear(CSR_MIP, MIP_STIP);
 	csr_set(CSR_MIE, MIP_MTIP);
 }
@@ -91,17 +100,34 @@ void sbi_timer_process(void)
 	csr_set(CSR_MIP, MIP_STIP);
 }
 
+const struct sbi_timer_device *sbi_timer_get_device(void)
+{
+	return timer_dev;
+}
+
+void sbi_timer_set_device(const struct sbi_timer_device *dev)
+{
+	if (!dev || timer_dev)
+		return;
+
+	timer_dev = dev;
+	if (!get_time_val && timer_dev->timer_value)
+		get_time_val = get_platform_ticks;
+}
+
 int sbi_timer_init(struct sbi_scratch *scratch, bool cold_boot)
 {
 	u64 *time_delta;
 	const struct sbi_platform *plat = sbi_platform_ptr(scratch);
-	int ret;
 
 	if (cold_boot) {
 		time_delta_off = sbi_scratch_alloc_offset(sizeof(*time_delta),
 							  "TIME_DELTA");
 		if (!time_delta_off)
 			return SBI_ENOMEM;
+
+		if (sbi_hart_has_feature(scratch, SBI_HART_HAS_TIME))
+			get_time_val = get_ticks;
 	} else {
 		if (!time_delta_off)
 			return SBI_ENOMEM;
@@ -110,24 +136,13 @@ int sbi_timer_init(struct sbi_scratch *scratch, bool cold_boot)
 	time_delta = sbi_scratch_offset_ptr(scratch, time_delta_off);
 	*time_delta = 0;
 
-	ret = sbi_platform_timer_init(plat, cold_boot);
-	if (ret)
-		return ret;
-
-	if (sbi_hart_has_feature(scratch, SBI_HART_HAS_TIME))
-		get_time_val = get_ticks;
-	else if (sbi_platform_has_timer_value(plat))
-		get_time_val = sbi_platform_timer_value;
-	else
-		/* There is no method to provide timer value */
-		return SBI_ENODEV;
-
-	return 0;
+	return sbi_platform_timer_init(plat, cold_boot);
 }
 
 void sbi_timer_exit(struct sbi_scratch *scratch)
 {
-	sbi_platform_timer_event_stop(sbi_platform_ptr(scratch));
+	if (timer_dev && timer_dev->timer_event_stop)
+		timer_dev->timer_event_stop();
 
 	csr_clear(CSR_MIP, MIP_STIP);
 	csr_clear(CSR_MIE, MIP_MTIP);