1 files changed, 62 insertions, 0 deletions
diff --git a/drivers/arm/css/sds/aarch64/sds_helpers.S b/drivers/arm/css/sds/aarch64/sds_helpers.S
new file mode 100644
index 0000000..3256c2b
--- /dev/null
+++ b/drivers/arm/css/sds/aarch64/sds_helpers.S
@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch.h>
+#include <asm_macros.S>
+#include <drivers/arm/css/sds.h>
+#include <platform_def.h>
+
+#include "../sds_private.h"
+
+	.globl	sds_get_primary_cpu_id
+
+	/*
+	 * int sds_get_primary_cpu_id(void);
+	 * Return the primary CPI ID from SDS Structure
+	 * Returns CPUID on success or -1 on failure
+	 */
+func sds_get_primary_cpu_id
+	mov_imm	x0, PLAT_ARM_SDS_MEM_BASE
+	mov	w2, #SDS_REGION_SIGNATURE
+	ldr	w1, [x0]
+
+	/* Check if the SDS region signature found */
+	cmp	w2, w1, uxth
+	b.ne	2f
+
+	/* Get the structure count from region descriptor in `w1 */
+	ubfx	w1, w1, #SDS_REGION_STRUCT_COUNT_SHIFT, #SDS_REGION_STRUCT_COUNT_WIDTH
+	cbz	w1, 2f
+	add	x0, x0, #SDS_REGION_DESC_SIZE
+
+	/* Initialize the loop iterator count in w3 */
+	mov	w3, #0
+loop_begin:
+	ldrh	w2, [x0]
+	cmp	w2, #SDS_AP_CPU_INFO_STRUCT_ID
+	b.ne	continue_loop
+
+	/* We have found the required structure */
+	ldr	w0, [x0,#(SDS_HEADER_SIZE + SDS_AP_CPU_INFO_PRIMARY_CPUID_OFFSET)]
+	ret
+continue_loop:
+	/* Increment the loop counter and exit loop if counter == structure count */
+	add	w3, w3, #0x1
+	cmp	w1, w3
+	b.eq	2f
+
+	/* Read the 2nd word in header */
+	ldr	w2, [x0,#4]
+	/* Get the structure size from header */
+	ubfx	x2, x2, #SDS_HEADER_STRUCT_SIZE_SHIFT, #SDS_HEADER_STRUCT_SIZE_WIDTH
+	/* Add the structure size and SDS HEADER SIZE to point to next header */
+	add	x2, x2, #SDS_HEADER_SIZE
+	add	x0, x0, x2
+	b	loop_begin
+2:
+	mov	w0, #0xffffffff
+	ret
+endfunc sds_get_primary_cpu_id