errata: workaround for Neoverse V1 errata 1852267

Neoverse V1 erratum 1852267 is a Cat B erratum present in r0p0 and
r1p0 of the V1 processor core. It is fixed in r1p1.

SDEN can be found here:
https://documentation-service.arm.com/static/60d499080320e92fa40b4625

Signed-off-by: Lauren Wehrmeister <lauren.wehrmeister@arm.com>
Change-Id: Ide5e0bc09371fbc91c2385ffdff74e604beb2dbe

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

@@ -333,6 +333,10 @@ For Neoverse V1, the following errata build flags are defined :
    CPU. This needs to be enabled only for revisions r0p0 and r1p0, it is fixed
    in r1p1.
 
+-  ``ERRATA_V1_1852267``: This applies errata 1852267 workaround to Neoverse-V1
+   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.

include/lib/cpus/aarch64/neoverse_v1.h

@@ -26,5 +26,6 @@
  ******************************************************************************/
 #define NEOVERSE_V1_ACTLR2_EL1					S3_0_C15_C1_1
 #define NEOVERSE_V1_ACTLR2_EL1_BIT_2				(ULL(1) << 2)
+#define NEOVERSE_V1_ACTLR2_EL1_BIT_28				(ULL(1) << 28)
 
 #endif /* NEOVERSE_V1_H */

lib/cpus/aarch64/neoverse_v1.S

@@ -77,6 +77,34 @@ func check_errata_1791573
 	b	cpu_rev_var_ls
 endfunc check_errata_1791573
 
+	/* --------------------------------------------------
+	 * Errata Workaround for Neoverse V1 Errata #1852267.
+	 * This applies to revisions r0p0 and r1p0, fixed in r1p1.
+	 * x0: variant[4:7] and revision[0:3] of current cpu.
+	 * Shall clobber: x0-x17
+	 * --------------------------------------------------
+	 */
+func errata_neoverse_v1_1852267_wa
+	/* Check workaround compatibility. */
+	mov	x17, x30
+	bl	check_errata_1852267
+	cbz	x0, 1f
+
+	/* Set bit 28 in ACTLR2_EL1 */
+	mrs	x1, NEOVERSE_V1_ACTLR2_EL1
+	orr	x1, x1, #NEOVERSE_V1_ACTLR2_EL1_BIT_28
+	msr	NEOVERSE_V1_ACTLR2_EL1, x1
+	isb
+1:
+	ret	x17
+endfunc errata_neoverse_v1_1852267_wa
+
+func check_errata_1852267
+	/* Applies to r0p0 and r1p0. */
+	mov	x1, #0x10
+	b	cpu_rev_var_ls
+endfunc check_errata_1852267
+
 	/* --------------------------------------------------
 	 * Errata Workaround for Neoverse V1 Erratum #1940577
 	 * This applies to revisions r1p0 - r1p1 and is open.
@@ -164,6 +192,7 @@ func neoverse_v1_errata_report
 	 */
 	report_errata ERRATA_V1_1774420, neoverse_v1, 1774420
 	report_errata ERRATA_V1_1791573, neoverse_v1, 1791573
+	report_errata ERRATA_V1_1852267, neoverse_v1, 1852267
 	report_errata ERRATA_V1_1940577, neoverse_v1, 1940577
 
 	ldp	x8, x30, [sp], #16
@@ -188,6 +217,11 @@ func neoverse_v1_reset_func
 	bl	errata_neoverse_v1_1791573_wa
 #endif
 
+#if ERRATA_V1_1852267
+	mov	x0, x18
+	bl	errata_neoverse_v1_1852267_wa
+#endif
+
 #if ERRATA_V1_1940577
 	mov	x0, x18
 	bl	errata_neoverse_v1_1940577_wa

lib/cpus/cpu-ops.mk

@@ -380,6 +380,10 @@ ERRATA_V1_1774420	?=0
 # to revisions r0p0 and r1p0 of the Neoverse V1 core, and was fixed in r1p1.
 ERRATA_V1_1791573	?=0
 
+# Flag to apply erratum 1852267 workaround during reset.  This erratum applies
+# to revisions r0p0 and r1p0 of the Neoverse V1 core, and was fixed in r1p1.
+ERRATA_V1_1852267	?=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
@@ -697,6 +701,10 @@ $(eval $(call add_define,ERRATA_V1_1774420))
 $(eval $(call assert_boolean,ERRATA_V1_1791573))
 $(eval $(call add_define,ERRATA_V1_1791573))
 
+# Process ERRATA_V1_1852267 flag
+$(eval $(call assert_boolean,ERRATA_V1_1852267))
+$(eval $(call add_define,ERRATA_V1_1852267))
+
 # Process ERRATA_V1_1940577 flag
 $(eval $(call assert_boolean,ERRATA_V1_1940577))
 $(eval $(call add_define,ERRATA_V1_1940577))