Merge "errata: workaround for Neoverse V1 errata 1966096" into integration

docs/design/cpu-specific-build-macros.rst

@@ -344,6 +344,11 @@ For Neoverse V1, the following errata build flags are defined :
    CPU. This needs to be enabled only for revision r1p0 and r1p1 of the
    CPU.
 
+-  ``ERRATA_V1_1966096``: This applies errata 1966096 workaround to Neoverse-V1
+   CPU. This needs to be enabled for revisions r1p0 and r1p1 of the CPU, the
+   issue is present in r0p0 as well but there is no workaround for that
+   revision.  It is still open.
+
 DSU Errata Workarounds
 ----------------------
 

lib/cpus/aarch64/neoverse_v1.S

 /*
- * Copyright (c) 2019-2021, ARM Limited. All rights reserved.
+ * Copyright (c) 2019-2021, Arm Limited. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -188,6 +188,42 @@ func check_errata_1940577
 	b	cpu_rev_var_range
 endfunc check_errata_1940577
 
+	/* --------------------------------------------------
+	 * Errata Workaround for Neoverse V1 Errata #1966096
+	 * This applies to revisions r1p0 - r1p1 and is open.
+	 * It also exists in r0p0 but there is no workaround
+	 * for that revision.
+	 * x0: variant[4:7] and revision[0:3] of current cpu.
+	 * Shall clobber: x0-x17
+	 * --------------------------------------------------
+	 */
+func errata_neoverse_v1_1966096_wa
+	/* Check workaround compatibility. */
+	mov	x17, x30
+	bl	check_errata_1966096
+	cbz	x0, 1f
+
+	/* Apply the workaround. */
+	mov	x0, #0x3
+	msr	S3_6_C15_C8_0, x0
+	ldr	x0, =0xEE010F12
+	msr	S3_6_C15_C8_2, x0
+	ldr	x0, =0xFFFF0FFF
+	msr	S3_6_C15_C8_3, x0
+	ldr	x0, =0x80000000003FF
+	msr	S3_6_C15_C8_1, x0
+	isb
+
+1:
+	ret	x17
+endfunc errata_neoverse_v1_1966096_wa
+
+func check_errata_1966096
+	mov	x1, #0x10
+	mov	x2, #0x11
+	b	cpu_rev_var_range
+endfunc check_errata_1966096
+
 	/* ---------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ---------------------------------------------
@@ -223,6 +259,7 @@ func neoverse_v1_errata_report
 	report_errata ERRATA_V1_1852267, neoverse_v1, 1852267
 	report_errata ERRATA_V1_1925756, neoverse_v1, 1925756
 	report_errata ERRATA_V1_1940577, neoverse_v1, 1940577
+	report_errata ERRATA_V1_1966096, neoverse_v1, 1966096
 
 	ldp	x8, x30, [sp], #16
 	ret
@@ -261,6 +298,11 @@ func neoverse_v1_reset_func
 	bl	errata_neoverse_v1_1940577_wa
 #endif
 
+#if ERRATA_V1_1966096
+	mov	x0, x18
+	bl	errata_neoverse_v1_1966096_wa
+#endif
+
 	ret	x19
 endfunc neoverse_v1_reset_func
 

lib/cpus/cpu-ops.mk

@@ -392,6 +392,11 @@ ERRATA_V1_1925756	?=0
 # to revisions r1p0 and r1p1 of the Neoverse V1 cpu.
 ERRATA_V1_1940577	?=0
 
+# Flag to apply erratum 1966096 workaround during reset. This erratum applies
+# to revisions r1p0 and r1p1 of the Neoverse V1 CPU and is open.  This issue
+# exists in r0p0 as well but there is no workaround for that revision.
+ERRATA_V1_1966096   ?=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
@@ -717,6 +722,10 @@ $(eval $(call add_define,ERRATA_V1_1925756))
 $(eval $(call assert_boolean,ERRATA_V1_1940577))
 $(eval $(call add_define,ERRATA_V1_1940577))
 
+# Process ERRATA_V1_1966096 flag
+$(eval $(call assert_boolean,ERRATA_V1_1966096))
+$(eval $(call add_define,ERRATA_V1_1966096))
+
 # Process ERRATA_DSU_798953 flag
 $(eval $(call assert_boolean,ERRATA_DSU_798953))
 $(eval $(call add_define,ERRATA_DSU_798953))