Workaround for Neoverse N1 erratum 1207823
Neoverse N1 erratum 1207823 is a Cat B erratum [1],
present in older revisions of the Neoverse N1 processor core.
The workaround is to set a bit in the implementation defined
CPUACTLR2_EL1 system register.
[1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.pjdoc-466751330-10325/index.html
Change-Id: Ia932337821f1ef0d644db3612480462a8d924d21
Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
diff --git a/lib/cpus/aarch64/neoverse_n1.S b/lib/cpus/aarch64/neoverse_n1.S
index a8ffa25..c9bcea8 100644
--- a/lib/cpus/aarch64/neoverse_n1.S
+++ b/lib/cpus/aarch64/neoverse_n1.S
@@ -158,6 +158,33 @@
endfunc check_errata_1165347
/* --------------------------------------------------
+ * Errata Workaround for Neoverse N1 Errata #1207823
+ * This applies to revision <=r2p0 of Neoverse N1.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_n1_1207823_wa
+ /* Compare x0 against revision r2p0 */
+ mov x17, x30
+ bl check_errata_1207823
+ cbz x0, 1f
+ mrs x1, NEOVERSE_N1_CPUACTLR2_EL1
+ orr x1, x1, NEOVERSE_N1_CPUACTLR2_EL1_BIT_11
+ msr NEOVERSE_N1_CPUACTLR2_EL1, x1
+ isb
+1:
+ ret x17
+endfunc errata_n1_1207823_wa
+
+func check_errata_1207823
+ /* Applies to <=r2p0 */
+ mov x1, #0x20
+ b cpu_rev_var_ls
+endfunc check_errata_1207823
+
+/* --------------------------------------------------
* Errata Workaround for Neoverse N1 Erratum 1315703.
* This applies to revision <= r3p0 of Neoverse N1.
* Inputs:
@@ -220,6 +247,11 @@
bl errata_n1_1165347_wa
#endif
+#if ERRATA_N1_1207823
+ mov x0, x18
+ bl errata_n1_1207823_wa
+#endif
+
#if ERRATA_N1_1315703
mov x0, x18
bl errata_n1_1315703_wa
@@ -285,6 +317,7 @@
report_errata ERRATA_N1_1073348, neoverse_n1, 1073348
report_errata ERRATA_N1_1130799, neoverse_n1, 1130799
report_errata ERRATA_N1_1165347, neoverse_n1, 1165347
+ report_errata ERRATA_N1_1207823, neoverse_n1, 1207823
report_errata ERRATA_N1_1315703, neoverse_n1, 1315703
report_errata ERRATA_DSU_936184, neoverse_n1, dsu_936184
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index faaf120..78efbeb 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -250,6 +250,10 @@
# only to revision <= r2p0 of the Neoverse N1 cpu.
ERRATA_N1_1165347 ?=0
+# Flag to apply erratum 1207823 workaround during reset. This erratum applies
+# only to revision <= r2p0 of the Neoverse N1 cpu.
+ERRATA_N1_1207823 ?=0
+
# Flag to apply erratum 1315703 workaround during reset. This erratum applies
# to revisions before r3p1 of the Neoverse N1 cpu.
ERRATA_N1_1315703 ?=1
@@ -455,6 +459,10 @@
$(eval $(call assert_boolean,ERRATA_N1_1165347))
$(eval $(call add_define,ERRATA_N1_1165347))
+# Process ERRATA_N1_1207823 flag
+$(eval $(call assert_boolean,ERRATA_N1_1207823))
+$(eval $(call add_define,ERRATA_N1_1207823))
+
# Process ERRATA_N1_1315703 flag
$(eval $(call assert_boolean,ERRATA_N1_1315703))
$(eval $(call add_define,ERRATA_N1_1315703))