Cortex-A55: Implement workaround for erratum 768277
Change-Id: Iebd45ef5e39ee7080235fb85414ce5b2e776f90c
Signed-off-by: Ambroise Vincent <ambroise.vincent@arm.com>
diff --git a/docs/cpu-specific-build-macros.rst b/docs/cpu-specific-build-macros.rst
index 315457a..897c771 100644
--- a/docs/cpu-specific-build-macros.rst
+++ b/docs/cpu-specific-build-macros.rst
@@ -97,6 +97,11 @@
Earlier revisions of the CPU have other errata which require the same
workaround in software, so they should be covered anyway.
+For Cortex-A55, the following errata build flags are defined :
+
+- ``ERRATA_A55_768277``: This applies errata 768277 workaround to Cortex-A55
+ CPU. This needs to be enabled only for revision r0p0 of the CPU.
+
For Cortex-A57, the following errata build flags are defined :
- ``ERRATA_A57_806969``: This applies errata 806969 workaround to Cortex-A57
diff --git a/include/lib/cpus/aarch64/cortex_a55.h b/include/lib/cpus/aarch64/cortex_a55.h
index 8b21e16..5db0f00 100644
--- a/include/lib/cpus/aarch64/cortex_a55.h
+++ b/include/lib/cpus/aarch64/cortex_a55.h
@@ -18,6 +18,13 @@
#define CORTEX_A55_CPUPWRCTLR_EL1 S3_0_C15_C2_7
#define CORTEX_A55_CPUECTLR_EL1 S3_0_C15_C1_4
+/*******************************************************************************
+ * CPU Auxiliary Control register specific definitions.
+ ******************************************************************************/
+#define CORTEX_A55_CPUACTLR_EL1 S3_0_C15_C1_0
+
+#define CORTEX_A55_CPUACTLR_EL1_DISABLE_DUAL_ISSUE (ULL(1) << 31)
+
/* Definitions of register field mask in CORTEX_A55_CPUPWRCTLR_EL1 */
#define CORTEX_A55_CORE_PWRDN_EN_MASK U(0x1)
diff --git a/lib/cpus/aarch64/cortex_a55.S b/lib/cpus/aarch64/cortex_a55.S
index b347e29..018c9db 100644
--- a/lib/cpus/aarch64/cortex_a55.S
+++ b/lib/cpus/aarch64/cortex_a55.S
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2017-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2017-2019, ARM Limited and Contributors. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
@@ -11,11 +11,49 @@
#include <cpu_macros.S>
#include <plat_macros.S>
+ /* --------------------------------------------------
+ * Errata Workaround for Cortex A55 Errata #768277.
+ * This applies only to revision r0p0 of Cortex A55.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_a55_768277_wa
+ /*
+ * Compare x0 against revision r0p0
+ */
+ mov x17, x30
+ bl check_errata_768277
+ cbz x0, 1f
+ mrs x1, CORTEX_A55_CPUACTLR_EL1
+ orr x1, x1, #CORTEX_A55_CPUACTLR_EL1_DISABLE_DUAL_ISSUE
+ msr CORTEX_A55_CPUACTLR_EL1, x1
+ isb
+1:
+ ret x17
+endfunc errata_a55_768277_wa
+
+func check_errata_768277
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_768277
+
func cortex_a55_reset_func
mov x19, x30
+
#if ERRATA_DSU_936184
bl errata_dsu_936184_wa
#endif
+
+ bl cpu_get_rev_var
+ mov x18, x0
+
+#if ERRATA_A55_768277
+ mov x0, x18
+ bl errata_a55_768277_wa
+#endif
+
ret x19
endfunc cortex_a55_reset_func
@@ -49,6 +87,7 @@
* "report_errata" is expecting it and it doesn't corrupt it.
*/
report_errata ERRATA_DSU_936184, cortex_a55, dsu_936184
+ report_errata ERRATA_A55_768277, cortex_a55, 768277
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 7824df2..2ada0be 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -79,6 +79,10 @@
# of by the rich OS.
ERRATA_A53_855873 ?=0
+# Flag to apply erratum 768277 workaround during reset. This erratum applies
+# only to revision r0p0 of the Cortex A55 cpu.
+ERRATA_A55_768277 ?=0
+
# Flag to apply erratum 806969 workaround during reset. This erratum applies
# only to revision r0p0 of the Cortex A57 cpu.
ERRATA_A57_806969 ?=0
@@ -148,6 +152,10 @@
$(eval $(call assert_boolean,ERRATA_A53_855873))
$(eval $(call add_define,ERRATA_A53_855873))
+# Process ERRATA_A55_768277 flag
+$(eval $(call assert_boolean,ERRATA_A55_768277))
+$(eval $(call add_define,ERRATA_A55_768277))
+
# Process ERRATA_A57_806969 flag
$(eval $(call assert_boolean,ERRATA_A57_806969))
$(eval $(call add_define,ERRATA_A57_806969))