fix(errata): workaround for Neoverse-N2 erratum 2138953
Neoverse-N2 erratum 2138953 is a Cat B erratum that applies to
revision r0p0 of CPU. It is still open. The workaround
is to write the value 4'b1001 to the PF_MODE bits in the
IMP_CPUECTLR2_EL1 register which will place the data prefetcher
in the most conservative mode instead of disabling it.
SDEN can be found here:
https://developer.arm.com/documentation/SDEN1982442/latest
Signed-off-by: nayanpatel-arm <nayankumar.patel@arm.com>
Change-Id: Ife0a4bece7ccf83cc99c1d5f5b5a43084bb69d64
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index bde6d97..9676ae7 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -403,6 +403,9 @@
- ``ERRATA_N2_2138956``: This applies errata 2138956 workaround to Neoverse-N2
CPU. This needs to be enabled for revision r0p0 of the CPU and is still open.
+- ``ERRATA_N2_2138953``: This applies errata 2138953 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 948f965..f414cb5 100644
--- a/include/lib/cpus/aarch64/neoverse_n2.h
+++ b/include/lib/cpus/aarch64/neoverse_n2.h
@@ -8,37 +8,45 @@
#define NEOVERSE_N2_H
/* Neoverse N2 ID register for revision r0p0 */
-#define NEOVERSE_N2_MIDR U(0x410FD490)
+#define NEOVERSE_N2_MIDR U(0x410FD490)
/*******************************************************************************
* CPU Power control register
******************************************************************************/
-#define NEOVERSE_N2_CPUPWRCTLR_EL1 S3_0_C15_C2_7
-#define NEOVERSE_N2_CORE_PWRDN_EN_BIT (ULL(1) << 0)
+#define NEOVERSE_N2_CPUPWRCTLR_EL1 S3_0_C15_C2_7
+#define NEOVERSE_N2_CORE_PWRDN_EN_BIT (ULL(1) << 0)
/*******************************************************************************
* CPU Extended Control register specific definitions.
******************************************************************************/
-#define NEOVERSE_N2_CPUECTLR_EL1 S3_0_C15_C1_4
-#define NEOVERSE_N2_CPUECTLR_EL1_EXTLLC_BIT (ULL(1) << 0)
-#define NEOVERSE_N2_CPUECTLR_EL1_PFSTIDIS_BIT (ULL(1) << 8)
+#define NEOVERSE_N2_CPUECTLR_EL1 S3_0_C15_C1_4
+#define NEOVERSE_N2_CPUECTLR_EL1_EXTLLC_BIT (ULL(1) << 0)
+#define NEOVERSE_N2_CPUECTLR_EL1_PFSTIDIS_BIT (ULL(1) << 8)
/*******************************************************************************
* 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)
+#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)
+#define NEOVERSE_N2_CPUACTLR2_EL1 S3_0_C15_C1_1
+#define NEOVERSE_N2_CPUACTLR2_EL1_BIT_2 (ULL(1) << 2)
/*******************************************************************************
* CPU Auxiliary Control register 5 specific definitions.
******************************************************************************/
-#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 S3_0_C15_C8_0
+#define NEOVERSE_N2_CPUACTLR5_EL1_BIT_44 (ULL(1) << 44)
+
+/*******************************************************************************
+ * CPU Auxiliary Control register specific definitions.
+ ******************************************************************************/
+#define NEOVERSE_N2_CPUECTLR2_EL1 S3_0_C15_C1_5
+#define NEOVERSE_N2_CPUECTLR2_EL1_PF_MODE_CNSRV ULL(9)
+#define CPUECTLR2_EL1_PF_MODE_LSB U(11)
+#define CPUECTLR2_EL1_PF_MODE_WIDTH U(4)
#endif /* NEOVERSE_N2_H */
diff --git a/lib/cpus/aarch64/neoverse_n2.S b/lib/cpus/aarch64/neoverse_n2.S
index 9e7bbf7..330cc59 100644
--- a/lib/cpus/aarch64/neoverse_n2.S
+++ b/lib/cpus/aarch64/neoverse_n2.S
@@ -183,6 +183,35 @@
b cpu_rev_var_ls
endfunc check_errata_2138956
+/* --------------------------------------------------
+ * Errata Workaround for Neoverse N2 Erratum 2138953.
+ * 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_2138953_wa
+ /* Check revision. */
+ mov x17, x30
+ bl check_errata_2138953
+ cbz x0, 1f
+
+ /* Apply instruction patching sequence */
+ mrs x1, NEOVERSE_N2_CPUECTLR2_EL1
+ mov x0, #NEOVERSE_N2_CPUECTLR2_EL1_PF_MODE_CNSRV
+ bfi x1, x0, #CPUECTLR2_EL1_PF_MODE_LSB, #CPUECTLR2_EL1_PF_MODE_WIDTH
+ msr NEOVERSE_N2_CPUECTLR2_EL1, x1
+1:
+ ret x17
+endfunc errata_n2_2138953_wa
+
+func check_errata_2138953
+ /* Applies to r0p0 */
+ mov x1, #0x00
+ b cpu_rev_var_ls
+endfunc check_errata_2138953
+
/* -------------------------------------------
* The CPU Ops reset function for Neoverse N2.
* -------------------------------------------
@@ -224,6 +253,11 @@
bl errata_n2_2138956_wa
#endif
+#if ERRATA_N2_2138953
+ mov x0, x18
+ bl errata_n2_2138953_wa
+#endif
+
#if ENABLE_AMU
/* Make sure accesses from EL0/EL1 and EL2 are not trapped to EL3 */
mrs x0, cptr_el3
@@ -287,8 +321,9 @@
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
+ report_errata ERRATA_N2_2189731, neoverse_n2, 2189731
report_errata ERRATA_N2_2138956, neoverse_n2, 2138956
+ report_errata ERRATA_N2_2138953, neoverse_n2, 2138953
ldp x8, x30, [sp], #16
ret
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index 6103a5a..1d470e2 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -441,6 +441,10 @@
# to revision r0p0 of the Neoverse N2 cpu and is still open.
ERRATA_N2_2138956 ?=0
+# Flag to apply erratum 2138953 workaround during reset. This erratum applies
+# to revision r0p0 of the Neoverse N2 cpu and is still open.
+ERRATA_N2_2138953 ?=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
@@ -822,6 +826,10 @@
$(eval $(call assert_boolean,ERRATA_N2_2138956))
$(eval $(call add_define,ERRATA_N2_2138956))
+# Process ERRATA_N2_2138953 flag
+$(eval $(call assert_boolean,ERRATA_N2_2138953))
+$(eval $(call add_define,ERRATA_N2_2138953))
+
# Process ERRATA_A710_2055002 flag
$(eval $(call assert_boolean,ERRATA_A710_2055002))
$(eval $(call add_define,ERRATA_A710_2055002))