lib: sbi: Implement firmware counters

RISC-V SBI v0.3 specification defines a set of firmware events that can
provide additional information about the current firmware context. All
of the firmware event monitoring are enabled now. The firmware
events must be defined as raw perf event with MSB set as specified in the
specification.

Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>

lib/sbi/sbi_timer.c

@@ -12,6 +12,7 @@
 #include <sbi/sbi_error.h>
 #include <sbi/sbi_hart.h>
 #include <sbi/sbi_platform.h>
+#include <sbi/sbi_pmu.h>
 #include <sbi/sbi_scratch.h>
 #include <sbi/sbi_timer.h>
 
@@ -88,6 +89,7 @@ void sbi_timer_set_delta_upper(ulong delta_upper)
 
 void sbi_timer_event_start(u64 next_event)
 {
+	sbi_pmu_ctr_incr_fw(SBI_PMU_FW_SET_TIMER);
 	if (timer_dev && timer_dev->timer_event_start)
 		timer_dev->timer_event_start(next_event);
 	csr_clear(CSR_MIP, MIP_STIP);