errata: workaround for Neoverse N2 erratum 2189731
Neoverse N2 erratum 2189731 is a Cat B erratum that applies to
revision r0p0 and is still open. The workaround is to set
CPUACTLR5_EL1[44] to 1 which will cause the CPP instruction to
invalidate the hardware prefetcher state trained from any EL.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: Iddc6a59adf9fa3cab560c46f2133e1f5a8b3ad03
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index a745ca5..0df4076 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -114,6 +114,33 @@
b cpu_rev_var_ls
endfunc check_errata_2025414
+/* ---------------------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2189731.
+ * This applies to revision r0p0 of Neoverse N2 and is still open.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * ---------------------------------------------------------------
+ */
+func errata_n2_2189731_wa
+ /* Compare x0 against revision r0p0 */
+ mov x17, x30
+ bl check_errata_2189731
+ cbz x0, 1f
+ mrs x1, NEOVERSE_N2_CPUACTLR5_EL1
+ orr x1, x1, NEOVERSE_N2_CPUACTLR5_EL1_BIT_44
+ msr NEOVERSE_N2_CPUACTLR5_EL1, x1
+
+1:
+ ret x17
+endfunc errata_n2_2189731_wa
+
+func check_errata_2189731
+ /* Applies to r0p0 */
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2189731
+
/* -------------------------------------------
* The CPU Ops reset function for Neoverse N2.
* -------------------------------------------
@@ -144,6 +171,11 @@
bl errata_n2_2025414_wa
#endif
+#if ERRATA_N2_2189731
+ mov x0, x18
+ bl errata_n2_2189731_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, cptr_el3
@@ -207,6 +239,7 @@
report_errata ERRATA_N2_2002655, neoverse_n2, 2002655
report_errata ERRATA_N2_2067956, neoverse_n2, 2067956
report_errata ERRATA_N2_2025414, neoverse_n2, 2025414
+ report_errata ERRATA_N2_2189731, neoverse_n2, 2189731
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index a630526..e0fc1f7 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -429,6 +429,10 @@
# to revision r0p0 of the Neoverse N2 cpu and is still open.
ERRATA_N2_2025414 ?=0
+# Flag to apply erratum 2189731 workaround during reset. This erratum applies
+# to revision r0p0 of the Neoverse N2 cpu and is still open.
+ERRATA_N2_2189731 ?=0
+
# Flag to apply erratum 2055002 workaround during reset. This erratum applies
# to revision r1p0, r2p0 of the Cortex-A710 cpu and is still open.
ERRATA_A710_2055002 ?=0
@@ -798,6 +802,10 @@
$(eval $(call assert_boolean,ERRATA_N2_2025414))
$(eval $(call add_define,ERRATA_N2_2025414))
+# Process ERRATA_N2_2189731 flag
+$(eval $(call assert_boolean,ERRATA_N2_2189731))
+$(eval $(call add_define,ERRATA_N2_2189731))
+
# Process ERRATA_A710_2055002 flag
$(eval $(call assert_boolean,ERRATA_A710_2055002))
$(eval $(call add_define,ERRATA_A710_2055002))