Add workaround for a Juno platform errata
This patch adds the recommended workaround for defect id 831273 by triggering
the event stream every 65536 cycles.
Change-Id: I62c947e64396f10af62af495e413d0af846d6628
diff --git a/include/lib/aarch64/arch.h b/include/lib/aarch64/arch.h
index 9186094..82a04c9 100644
--- a/include/lib/aarch64/arch.h
+++ b/include/lib/aarch64/arch.h
@@ -167,6 +167,10 @@
#define EL0VTEN_BIT (1 << 8)
#define EL0PCTEN_BIT (1 << 0)
#define EL0VCTEN_BIT (1 << 1)
+#define EVNTEN_BIT (1 << 2)
+#define EVNTDIR_BIT (1 << 3)
+#define EVNTI_SHIFT 4
+#define EVNTI_MASK 0xf
/* CPTR_EL3 definitions */
#define TCPAC_BIT (1 << 31)
diff --git a/lib/aarch64/cpu_helpers.S b/lib/aarch64/cpu_helpers.S
index 8d063c4..b85e743 100644
--- a/lib/aarch64/cpu_helpers.S
+++ b/lib/aarch64/cpu_helpers.S
@@ -64,6 +64,14 @@
msr s3_1_c11_c0_2, x0
smp_setup_begin:
+ /* ---------------------------------------------
+ * Enable the event stream every 65536 cycles
+ * ---------------------------------------------
+ */
+ mov x0, #(0xf << EVNTI_SHIFT)
+ orr x0, x0, #EVNTEN_BIT
+ msr CNTKCTL_EL1, x0
+
mrs x0, CPUECTLR_EL1
orr x0, x0, #CPUECTLR_SMP_BIT
msr CPUECTLR_EL1, x0
