fix(errata): workaround for Cortex-X2 erratum 2216384

Cortex-X2 erratum 2216384 is a Cat B erratum that applies to
revisions r0p0, r1p0 and r2p0 of CPU. It is fixed in r2p1.
The workaround is to set CPUACTLR5_EL1[17] to 1'b1 followed by
applying an instruction patching sequence.

SDEN can be found here:
https://developer.arm.com/documentation/SDEN1775100/latest

Signed-off-by: Bipin Ravi <bipin.ravi@arm.com>
Change-Id: I3c216161678887c06a28c59644e784e0c7d37bab

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

@@ -462,6 +462,10 @@ For Cortex-X2, the following errata build flags are defined :
    Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
    r2p0 of the CPU, it is fixed in r2p1.
 
+-  ``ERRATA_X2_2216384``: This applies errata 2216384 workaround to
+   Cortex-X2 CPU. This needs to be enabled only for revisions r0p0, r1p0 and
+   r2p0 of the CPU, it is fixed in r2p1.
+
 DSU Errata Workarounds
 ----------------------
 

include/lib/cpus/aarch64/cortex_x2.h

@@ -34,6 +34,7 @@
  * CPU Auxiliary Control Register 5 definitions
  ******************************************************************************/
 #define CORTEX_X2_CPUACTLR5_EL1					S3_0_C15_C8_0
+#define CORTEX_X2_CPUACTLR5_EL1_BIT_17				(ULL(1) << 17)
 
 /*******************************************************************************
  * CPU Implementation Specific Selected Instruction registers

lib/cpus/aarch64/cortex_x2.S

@@ -184,6 +184,44 @@ func check_errata_2081180
 	b	cpu_rev_var_ls
 endfunc check_errata_2081180
 
+	/* --------------------------------------------------
+	 * Errata Workaround for Cortex X2 Errata 2216384.
+	 * This applies to revisions r0p0, r1p0, and r2p0
+	 * and is fixed in r2p1.
+	 * x0: variant[4:7] and revision[0:3] of current cpu.
+	 * Shall clobber: x0, x1, x17
+	 * --------------------------------------------------
+	 */
+func errata_x2_2216384_wa
+	/* Check workaround compatibility. */
+	mov	x17, x30
+	bl	check_errata_2216384
+	cbz	x0, 1f
+
+	mrs	x1, CORTEX_X2_CPUACTLR5_EL1
+	orr	x1, x1, CORTEX_X2_CPUACTLR5_EL1_BIT_17
+	msr	CORTEX_X2_CPUACTLR5_EL1, x1
+
+	/* Apply instruction patching sequence */
+	ldr	x0, =0x5
+	msr	CORTEX_X2_IMP_CPUPSELR_EL3, x0
+	ldr	x0, =0x10F600E000
+	msr	CORTEX_X2_IMP_CPUPOR_EL3, x0
+	ldr	x0, =0x10FF80E000
+	msr	CORTEX_X2_IMP_CPUPMR_EL3, x0
+	ldr	x0, =0x80000000003FF
+	msr	CORTEX_X2_IMP_CPUPCR_EL3, x0
+	isb
+
+1:
+	ret	x17
+endfunc errata_x2_2216384_wa
+
+func check_errata_2216384
+	/* Applies to r0p0 - r2p0 */
+	mov	x1, #0x20
+	b	cpu_rev_var_ls
+endfunc check_errata_2216384
 	/* ----------------------------------------------------
 	 * HW will do the cache maintenance while powering down
 	 * ----------------------------------------------------
@@ -219,6 +257,7 @@ func cortex_x2_errata_report
 	report_errata ERRATA_X2_2083908, cortex_x2, 2083908
 	report_errata ERRATA_X2_2017096, cortex_x2, 2017096
 	report_errata ERRATA_X2_2081180, cortex_x2, 2081180
+	report_errata ERRATA_X2_2216384, cortex_x2, 2216384
 
 	ldp	x8, x30, [sp], #16
 	ret
@@ -261,6 +300,11 @@ func cortex_x2_reset_func
 	bl	errata_x2_2081180_wa
 #endif
 
+#if ERRATA_X2_2216384
+	mov	x0, x18
+	bl	errata_x2_2216384_wa
+#endif
+
 	ret x19
 endfunc cortex_x2_reset_func
 

lib/cpus/cpu-ops.mk

@@ -517,6 +517,11 @@ ERRATA_X2_2017096	?=0
 # r2p1.
 ERRATA_X2_2081180	?=0
 
+# Flag to apply erratum 2216384 workaround during reset. This erratum applies
+# only to revisions r0p0, r1p0 and r2p0 of the Cortex-X2 cpu, it is fixed in
+# r2p1.
+ERRATA_X2_2216384	?=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
@@ -962,6 +967,10 @@ $(eval $(call add_define,ERRATA_X2_2017096))
 $(eval $(call assert_boolean,ERRATA_X2_2081180))
 $(eval $(call add_define,ERRATA_X2_2081180))
 
+# Process ERRATA_X2_2216384 flag
+$(eval $(call assert_boolean,ERRATA_X2_2216384))
+$(eval $(call add_define,ERRATA_X2_2216384))
+
 # Process ERRATA_DSU_798953 flag
 $(eval $(call assert_boolean,ERRATA_DSU_798953))
 $(eval $(call add_define,ERRATA_DSU_798953))