fix(errata): workaround for Neoverse-N2 erratum 2138958
Neoverse-N2 erratum 2138958 is a Cat B erratum that applies to
revision r0p0 of CPU. It is still open. The workaround
is to set CPUACTLR5_EL1[13] to 1'b1.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Signed-off-by: nayanpatel-arm <nayankumar.patel@arm.com>
Change-Id: I5247f8f8eef08d38c169aad6d2c5501ac387c720
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index b19c534..cd4d0fd 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -423,6 +423,9 @@
- ``ERRATA_N2_2242415``: This applies errata 2242415 workaround to Neoverse-N2
CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
+- ``ERRATA_N2_2138958``: This applies errata 2138958 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 8ba62a3..a457f2a 100644
--- a/include/lib/cpus/aarch64/neoverse_n2.h
+++ b/include/lib/cpus/aarch64/neoverse_n2.h
@@ -41,6 +41,7 @@
******************************************************************************/
#define NEOVERSE_N2_CPUACTLR5_EL1 S3_0_C15_C8_0
#define NEOVERSE_N2_CPUACTLR5_EL1_BIT_44 (ULL(1) << 44)
+#define NEOVERSE_N2_CPUACTLR5_EL1_BIT_13 (ULL(1) << 13)
/*******************************************************************************
* CPU Auxiliary Control register specific definitions.
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index c197590..ff569fb 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -240,6 +240,34 @@
b cpu_rev_var_ls
endfunc check_errata_2138953
+/* --------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2138958.
+ * This applies to revision r0p0 of Neoverse N2. it is still open.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x1, x17
+ * --------------------------------------------------
+ */
+func errata_n2_2138958_wa
+ /* Check revision. */
+ mov x17, x30
+ bl check_errata_2138958
+ cbz x0, 1f
+
+ /* Apply instruction patching sequence */
+ mrs x1, NEOVERSE_N2_CPUACTLR5_EL1
+ orr x1, x1, NEOVERSE_N2_CPUACTLR5_EL1_BIT_13
+ msr NEOVERSE_N2_CPUACTLR5_EL1, x1
+1:
+ ret x17
+endfunc errata_n2_2138958_wa
+
+func check_errata_2138958
+ /* Applies to r0p0 */
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2138958
+
/* -------------------------------------------
* The CPU Ops reset function for Neoverse N2.
* -------------------------------------------
@@ -291,6 +319,11 @@
bl errata_n2_2242415_wa
#endif
+#if ERRATA_N2_2138958
+ mov x0, x18
+ bl errata_n2_2138958_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, cptr_el3
@@ -358,6 +391,7 @@
report_errata ERRATA_N2_2138956, neoverse_n2, 2138956
report_errata ERRATA_N2_2138953, neoverse_n2, 2138953
report_errata ERRATA_N2_2242415, neoverse_n2, 2242415
+ report_errata ERRATA_N2_2138958, neoverse_n2, 2138958
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 4224fcc..b676987 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -465,6 +465,10 @@
# to revision r0p0 of the Neoverse N2 cpu and is still open.
ERRATA_N2_2242415 ?=0
+# Flag to apply erratum 2138958 workaround during reset. This erratum applies
+# to revision r0p0 of the Neoverse N2 cpu and is still open.
+ERRATA_N2_2138958 ?=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
@@ -870,6 +874,10 @@
$(eval $(call assert_boolean,ERRATA_N2_2242415))
$(eval $(call add_define,ERRATA_N2_2242415))
+# Process ERRATA_N2_2138958 flag
+$(eval $(call assert_boolean,ERRATA_N2_2138958))
+$(eval $(call add_define,ERRATA_N2_2138958))
+
# Process ERRATA_A710_2055002 flag
$(eval $(call assert_boolean,ERRATA_A710_2055002))
$(eval $(call add_define,ERRATA_A710_2055002))
