errata: workaround for Neoverse N2 erratum 2067956
Neoverse N2 erratum 2067956 is a Cat B erratum that applies to
revision r0p0 and is still open. The workaround is to set
CPUACTLR_EL1[46] to force L2 tag ECC inline correction mode.
This workaround works on revision r0p0.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: Ie92d18a379c66675b5c1c50fd0b8dde130848b21
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 9b8b0be..1f99892 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -378,6 +378,11 @@
Cortex-A710 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
r2p0 of the CPU. It is still open.
+For Neoverse N2, the following errata build flags are defined :
+
+- ``ERRATA_N2_2067956``: This applies errata 2067956 workaround to Neoverse-N2
+ CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
+
DSU Errata Workarounds
----------------------
diff --git a/include/lib/cpus/aarch64/neoverse_n2.h b/include/lib/cpus/aarch64/neoverse_n2.h
index 7cbd8c1..a7211d2 100644
--- a/include/lib/cpus/aarch64/neoverse_n2.h
+++ b/include/lib/cpus/aarch64/neoverse_n2.h
@@ -25,6 +25,12 @@
/*******************************************************************************
* CPU Auxiliary Control register specific definitions.
******************************************************************************/
+#define NEOVERSE_N2_CPUACTLR_EL1 S3_0_C15_C1_0
+#define NEOVERSE_N2_CPUACTLR_EL1_BIT_46 (ULL(1) << 46)
+
+/*******************************************************************************
+ * CPU Auxiliary Control register 2 specific definitions.
+ ******************************************************************************/
#define NEOVERSE_N2_CPUACTLR2_EL1 S3_0_C15_C1_1
#define NEOVERSE_N2_CPUACTLR2_EL1_BIT_2 (ULL(1) << 2)
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index 44db0b3..1ab5412 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -61,6 +61,32 @@
b cpu_rev_var_ls
endfunc check_errata_2002655
+/* ---------------------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2067956.
+ * 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_2067956_wa
+ /* Compare x0 against revision r0p0 */
+ mov x17, x30
+ bl check_errata_2067956
+ cbz x0, 1f
+ mrs x1, NEOVERSE_N2_CPUACTLR_EL1
+ orr x1, x1, NEOVERSE_N2_CPUACTLR_EL1_BIT_46
+ msr NEOVERSE_N2_CPUACTLR_EL1, x1
+1:
+ ret x17
+endfunc errata_n2_2067956_wa
+
+func check_errata_2067956
+ /* Applies to r0p0 */
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2067956
+
/* -------------------------------------------------
* The CPU Ops reset function for Neoverse N2.
* -------------------------------------------------
@@ -81,6 +107,11 @@
orr x0, x0, #NEOVERSE_N2_CPUACTLR2_EL1_BIT_2
msr NEOVERSE_N2_CPUACTLR2_EL1, x0
+#if ERRATA_N2_2067956
+ mov x0, x18
+ bl errata_n2_2067956_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, cptr_el3
@@ -97,9 +128,9 @@
#if NEOVERSE_Nx_EXTERNAL_LLC
/* Some systems may have External LLC, core needs to be made aware */
- mrs x0, NEOVERSE_N2_CPUECTLR_EL1
- orr x0, x0, NEOVERSE_N2_CPUECTLR_EL1_EXTLLC_BIT
- msr NEOVERSE_N2_CPUECTLR_EL1, x0
+ mrs x0, NEOVERSE_N2_CPUECTLR_EL1
+ orr x0, x0, NEOVERSE_N2_CPUECTLR_EL1_EXTLLC_BIT
+ msr NEOVERSE_N2_CPUECTLR_EL1, x0
#endif
bl cpu_get_rev_var
@@ -111,7 +142,7 @@
#endif
isb
- ret x19
+ ret x19
endfunc neoverse_n2_reset_func
func neoverse_n2_core_pwr_dwn
@@ -142,6 +173,7 @@
* checking functions of each errata.
*/
report_errata ERRATA_N2_2002655, neoverse_n2, 2002655
+ report_errata ERRATA_N2_2067956, neoverse_n2, 2067956
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 73f977b..b8576e9 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -421,6 +421,10 @@
# to revisions r0p0, r1p0 and r2p0 of the Cortex-A710 cpu and is still open.
ERRATA_A710_2081180 ?=0
+# Flag to apply erratum 2067956 workaround during reset. This erratum applies
+# to revision r0p0 of the Neoverse N2 cpu and is still open.
+ERRATA_N2_2067956 ?=0
+
# Flag to apply DSU erratum 798953. This erratum applies to DSUs revision r0p0.
# Applying the workaround results in higher DSU power consumption on idle.
ERRATA_DSU_798953 ?=0
@@ -774,6 +778,10 @@
$(eval $(call assert_boolean,ERRATA_A710_2081180))
$(eval $(call add_define,ERRATA_A710_2081180))
+# Process ERRATA_N2_2067956 flag
+$(eval $(call assert_boolean,ERRATA_N2_2067956))
+$(eval $(call add_define,ERRATA_N2_2067956))
+
# Process ERRATA_DSU_798953 flag
$(eval $(call assert_boolean,ERRATA_DSU_798953))
$(eval $(call add_define,ERRATA_DSU_798953))