errata: workaround for Neoverse V1 errata 1940577
Neoverse V1 erratum 1940577 is a Cat B erratum, present in some
revisions of the V1 processor core. The workaround is to insert a
DMB ST before acquire atomic instructions without release semantics.
This issue is present in revisions r0p0 - r1p1 but this workaround
only applies to revisions r1p0 - r1p1, there is no workaround for older
versions.
SDEN can be found here:
https://documentation-service.arm.com/static/60d499080320e92fa40b4625
Signed-off-by: John Powell <john.powell@arm.com>
Change-Id: I210ad7d8f31c81b6ac51b028dfbce75a725c11aa
diff --git a/docs/design/cpu-specific-build-macros.rst b/docs/design/cpu-specific-build-macros.rst
index 8d17d35..949845a 100644
--- a/docs/design/cpu-specific-build-macros.rst
+++ b/docs/design/cpu-specific-build-macros.rst
@@ -329,6 +329,10 @@
CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
in r1p1.
+- ``ERRATA_V1_1940577``: This applies errata 1940577 workaround to Neoverse-V1
+ CPU. This needs to be enabled only for revision r1p0 and r1p1 of the
+ CPU.
+
DSU Errata Workarounds
----------------------
diff --git a/lib/cpus/aarch64/neoverse_v1.S b/lib/cpus/aarch64/neoverse_v1.S
index d461b10..cee0bb7 100644
--- a/lib/cpus/aarch64/neoverse_v1.S
+++ b/lib/cpus/aarch64/neoverse_v1.S
@@ -49,6 +49,61 @@
b cpu_rev_var_ls
endfunc check_errata_1791573
+ /* --------------------------------------------------
+ * Errata Workaround for Neoverse V1 Erratum #1940577
+ * This applies to revisions r1p0 - r1p1 and is open.
+ * It also exists in r0p0 but there is no fix in that
+ * revision.
+ * Inputs:
+ * x0: variant[4:7] and revision[0:3] of current cpu.
+ * Shall clobber: x0-x17
+ * --------------------------------------------------
+ */
+func errata_neoverse_v1_1940577_wa
+ /* Compare x0 against revisions r1p0 - r1p1 */
+ mov x17, x30
+ bl check_errata_1940577
+ cbz x0, 1f
+
+ mov x0, #0
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3900002
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF00083
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ mov x0, #1
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3800082
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF00083
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ mov x0, #2
+ msr S3_6_C15_C8_0, x0
+ ldr x0, =0x10E3800200
+ msr S3_6_C15_C8_2, x0
+ ldr x0, =0x10FFF003E0
+ msr S3_6_C15_C8_3, x0
+ ldr x0, =0x2001003FF
+ msr S3_6_C15_C8_1, x0
+
+ isb
+1:
+ ret x17
+endfunc errata_neoverse_v1_1940577_wa
+
+func check_errata_1940577
+ /* Applies to revisions r1p0 - r1p1. */
+ mov x1, #0x10
+ mov x2, #0x11
+ b cpu_rev_var_range
+endfunc check_errata_1940577
+
/* ---------------------------------------------
* HW will do the cache maintenance while powering down
* ---------------------------------------------
@@ -80,6 +135,7 @@
* checking functions of each errata.
*/
report_errata ERRATA_V1_1791573, neoverse_v1, 1791573
+ report_errata ERRATA_V1_1940577, neoverse_v1, 1940577
ldp x8, x30, [sp], #16
ret
@@ -98,6 +154,11 @@
bl errata_neoverse_v1_1791573_wa
#endif
+#if ERRATA_V1_1940577
+ mov x0, x18
+ bl errata_neoverse_v1_1940577_wa
+#endif
+
ret x19
endfunc neoverse_v1_reset_func
diff --git a/lib/cpus/cpu-ops.mk b/lib/cpus/cpu-ops.mk
index b34fed6..6f80d2d 100644
--- a/lib/cpus/cpu-ops.mk
+++ b/lib/cpus/cpu-ops.mk
@@ -376,6 +376,10 @@
# to revisions r0p0 and r1p0 of the Neoverse V1 core, and was fixed in r1p1.
ERRATA_V1_1791573 ?=0
+# Flag to apply erratum 1940577 workaround during reset. This erratum applies
+# to revisions r1p0 and r1p1 of the Neoverse V1 cpu.
+ERRATA_V1_1940577 ?=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
@@ -685,6 +689,10 @@
$(eval $(call assert_boolean,ERRATA_V1_1791573))
$(eval $(call add_define,ERRATA_V1_1791573))
+# Process ERRATA_V1_1940577 flag
+$(eval $(call assert_boolean,ERRATA_V1_1940577))
+$(eval $(call add_define,ERRATA_V1_1940577))
+
# Process ERRATA_DSU_798953 flag
$(eval $(call assert_boolean,ERRATA_DSU_798953))
$(eval $(call add_define,ERRATA_DSU_798953))