utils: Fix ms timer accuracy

Additionally add BPMP delay timers for future use.

bootloader/soc/bpmp.c

@@ -216,3 +216,37 @@ void bpmp_clk_rate_set(bpmp_freq_t fid)
 	}
 }
 
+// The following functions halt BPMP to reduce power while sleeping.
+// They are not as accurate as RTC at big values but they guarantee time+ delay.
+void bpmp_usleep(u32 us)
+{
+	u32 delay;
+
+	// Each iteration takes 1us.
+	while (us)
+	{
+		delay = (us > HALT_COP_MAX_CNT) ? HALT_COP_MAX_CNT : us;
+		us -= delay;
+
+		FLOW_CTLR(FLOW_CTLR_HALT_COP_EVENTS) = HALT_COP_WAIT_EVENT | HALT_COP_USEC | delay;
+	}
+}
+
+void bpmp_msleep(u32 ms)
+{
+	u32 delay;
+
+	// Iteration time is variable. ~200 - 1000us.
+	while (ms)
+	{
+		delay = (ms > HALT_COP_MAX_CNT) ? HALT_COP_MAX_CNT : ms;
+		ms -= delay;
+
+		FLOW_CTLR(FLOW_CTLR_HALT_COP_EVENTS) = HALT_COP_WAIT_EVENT | HALT_COP_MSEC | delay;
+	}
+}
+
+void bpmp_halt()
+{
+	FLOW_CTLR(FLOW_CTLR_HALT_COP_EVENTS) = HALT_COP_WAIT_EVENT | HALT_COP_JTAG;
+}