@@ -74,6 +74,20 @@ config ARM_ARCH_TIMER
 	bool
 	select CLKSRC_OF if OF
 
+config ARM_ARCH_TIMER_EVTSTREAM
+	bool "Support for ARM architected timer event stream generation"
+	default y if ARM_ARCH_TIMER
+	help
+	  This option enables support for event stream generation based on
+	  the ARM architected timer. It is used for waking up CPUs executing
+	  the wfe instruction at a frequency represented as a power-of-2
+	  divisor of the clock rate. An event stream might be useful for
+	  imposing timeout on a wfe, safeguarding against any programming
+	  errors in case an expected event is not generated or even to
+	  implement wfe-based timeouts for userspace locking implementations.
+	  This can be disabled for hardware validation purposes to detect any
+	  hardware anomalies of missing events.
+
 config ARM_GLOBAL_TIMER
 	bool
 	select CLKSRC_OF if OF

@@ -123,6 +123,26 @@ static int arch_timer_set_next_event_phys(unsigned long evt,
 	return 0;
 }
 
+#ifdef CONFIG_ARM_ARCH_TIMER_EVTSTREAM
+static void arch_timer_setup_evtstream(void)
+{
+	int evt_stream_div, pos;
+
+	/* Find the closest power of two to the divisor */
+	evt_stream_div = arch_timer_rate / ARCH_TIMER_EVT_STREAM_FREQ;
+	pos = fls(evt_stream_div);
+	if (pos > 1 && !(evt_stream_div & (1 << (pos - 2))))
+		pos--;
+	/* enable event stream */
+	arch_timer_evtstrm_config(true, min(pos, 15));
+}
+#else
+static void arch_timer_setup_evtstream(void)
+{
+	arch_timer_evtstrm_config(false, 0);
+}
+#endif
+
 static int arch_timer_setup(struct clock_event_device *clk)
 {
 	clk->features = CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP;

@@ -154,6 +174,7 @@ static int arch_timer_setup(struct clock_event_device *clk)
 	}
 
 	arch_counter_set_user_access();
+	arch_timer_setup_evtstream();
 
 	return 0;
 }

@@ -37,6 +37,8 @@
 #define ARCH_TIMER_USR_VT_ACCESS_EN	(1 << 8) /* virtual timer registers */
 #define ARCH_TIMER_USR_PT_ACCESS_EN	(1 << 9) /* physical timer registers */
 
+#define ARCH_TIMER_EVT_STREAM_FREQ	10000	/* 100us */
+
 #ifdef CONFIG_ARM_ARCH_TIMER
 
 extern u32 arch_timer_get_rate(void);