[PATCH v2 4/5] vexpress64: Enable OF_CONTROL and OF_BOARD for VExpress64

[Peter Hoyes <peter.hoyes@arm.com>]

From: Peter Hoyes <Peter.Hoyes@arm.com>

Capture x0 in lowlevel_init.S as potential fdt address. Modify
board_fdt_blob_setup to use fdt address from either vexpress_aemv8.h
or lowlevel_init.S.

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
---
 board/armltd/vexpress64/Makefile        |  2 +-
 board/armltd/vexpress64/lowlevel_init.S | 12 ++++++++++++
 board/armltd/vexpress64/vexpress64.c    | 26 +++++++++++++++++++++++++
 3 files changed, 39 insertions(+), 1 deletion(-)
 create mode 100644 board/armltd/vexpress64/lowlevel_init.S

diff --git a/board/armltd/vexpress64/Makefile b/board/armltd/vexpress64/Makefile
index 868dc4f629..1878fbed4e 100644
--- a/board/armltd/vexpress64/Makefile
+++ b/board/armltd/vexpress64/Makefile
@@ -3,5 +3,5 @@
 # (C) Copyright 2000-2004
 # Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 
-obj-y	:= vexpress64.o
+obj-y	:= vexpress64.o lowlevel_init.o
 obj-$(CONFIG_TARGET_VEXPRESS64_JUNO)	+= pcie.o
diff --git a/board/armltd/vexpress64/lowlevel_init.S b/board/armltd/vexpress64/lowlevel_init.S
new file mode 100644
index 0000000000..3dcfb85d0e
--- /dev/null
+++ b/board/armltd/vexpress64/lowlevel_init.S
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * (C) Copyright 2021 Arm Limited
+ */
+
+.global save_boot_params
+save_boot_params:
+
+	adr	x8, prior_stage_fdt_address
+	str	x0, [x8]
+
+	b	save_boot_params_ret
diff --git a/board/armltd/vexpress64/vexpress64.c b/board/armltd/vexpress64/vexpress64.c
index d2f307cca5..d17b463be5 100644
--- a/board/armltd/vexpress64/vexpress64.c
+++ b/board/armltd/vexpress64/vexpress64.c
@@ -85,7 +85,15 @@ int dram_init_banksize(void)
 	return 0;
 }
 
+/* Assigned in lowlevel_init.S
+ * Push the variable into the .data section so that it
+ * does not get cleared later.
+ */
+unsigned long __section(".data") prior_stage_fdt_address;
+
 #ifdef CONFIG_OF_BOARD
+
+#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
 #define JUNO_FLASH_SEC_SIZE	(256 * 1024)
 static phys_addr_t find_dtb_in_nor_flash(const char *partname)
 {
@@ -130,9 +138,11 @@ static phys_addr_t find_dtb_in_nor_flash(const char *partname)
 
 	return ~0;
 }
+#endif
 
 void *board_fdt_blob_setup(int *err)
 {
+#ifdef CONFIG_TARGET_VEXPRESS64_JUNO
 	phys_addr_t fdt_rom_addr = find_dtb_in_nor_flash(CONFIG_JUNO_DTB_PART);
 
 	*err = 0;
@@ -142,6 +152,22 @@ void *board_fdt_blob_setup(int *err)
 	}
 
 	return (void *)fdt_rom_addr;
+#endif
+
+#ifdef VEXPRESS_FDT_ADDR
+	if (fdt_magic(VEXPRESS_FDT_ADDR) == FDT_MAGIC) {
+		*err = 0;
+		return (void *)VEXPRESS_FDT_ADDR;
+	}
+#endif
+
+	if (fdt_magic(prior_stage_fdt_address) == FDT_MAGIC) {
+		*err = 0;
+		return (void *)prior_stage_fdt_address;
+	}
+
+	*err = -ENXIO;
+	return NULL;
 }
 #endif
 
-- 
2.25.1