Cortex-A15: Implement workaround for errata 816470

Change-Id: I9755252725be25bfd0147839d7df56888424ff84
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>

docs/cpu-specific-build-macros.rst

@@ -71,6 +71,11 @@ for it to specify which errata workarounds should be enabled or not.
 The value of the build flags is 0 by default, that is, disabled. A value of 1
 will enable it.
 
+For Cortex-A15, the following errata build flags are defined :
+
+-  ``ERRATA_A15_816470``: This applies errata 816470 workaround to Cortex-A15
+   CPU. This needs to be enabled only for revision >= r3p0 of the CPU.
+
 For Cortex-A53, the following errata build flags are defined :
 
 -  ``ERRATA_A53_819472``: This applies errata 819472 workaround to all

lib/cpus/aarch32/cortex_a15.S

 /*
- * Copyright (c) 2016-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2016-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -29,6 +29,13 @@ func cortex_a15_disable_smp
 	bic	r0, #CORTEX_A15_ACTLR_SMP_BIT
 	stcopr	r0, ACTLR
 	isb
+#if ERRATA_A15_816470
+	/*
+	 * Invalidate any TLB address
+	 */
+	mov	r0, #0
+	stcopr	r0, TLBIMVA
+#endif
 	dsb	sy
 	bx	lr
 endfunc cortex_a15_disable_smp
@@ -41,6 +48,20 @@ func cortex_a15_enable_smp
 	bx	lr
 endfunc cortex_a15_enable_smp
 
+	/* ----------------------------------------------------
+	 * Errata Workaround for Cortex A15 Errata #816470.
+	 * This applies only to revision >= r3p0 of Cortex A15.
+	 * ----------------------------------------------------
+	 */
+func check_errata_816470
+	/*
+	 * Even though this is only needed for revision >= r3p0, it is always
+	 * applied because of the low cost of the workaround.
+	 */
+	mov	r0, #ERRATA_APPLIES
+	bx	lr
+endfunc check_errata_816470
+
 func check_errata_cve_2017_5715
 #if WORKAROUND_CVE_2017_5715
 	mov	r0, #ERRATA_APPLIES
@@ -64,6 +85,7 @@ func cortex_a15_errata_report
 	 * Report all errata. The revision-variant information is passed to
 	 * checking functions of each errata.
 	 */
+	report_errata ERRATA_A15_816470, cortex_a15, 816470
 	report_errata WORKAROUND_CVE_2017_5715, cortex_a15, cve_2017_5715
 
 	pop	{r12, lr}

lib/cpus/cpu-ops.mk

@@ -53,6 +53,10 @@ endif
 # These should be enabled by the platform if the erratum workaround needs to be
 # applied.
 
+# Flag to apply erratum 816470 workaround during power down. This erratum
+# applies only to revision >= r3p0 of the Cortex A15 cpu.
+ERRATA_A15_816470	?=0
+
 # Flag to apply erratum 819472 workaround during reset. This erratum applies
 # only to revision <= r0p1 of the Cortex A53 cpu.
 ERRATA_A53_819472	?=0
@@ -196,6 +200,10 @@ ERRATA_N1_1043202	?=1
 # higher DSU power consumption on idle.
 ERRATA_DSU_936184	?=0
 
+# Process ERRATA_A15_816470 flag
+$(eval $(call assert_boolean,ERRATA_A15_816470))
+$(eval $(call add_define,ERRATA_A15_816470))
+
 # Process ERRATA_A53_819472 flag
 $(eval $(call assert_boolean,ERRATA_A53_819472))
 $(eval $(call add_define,ERRATA_A53_819472))