[PATCH v2] riscv: ax25: bypass malloc when spl fit boots from ram

[Rick Chen <rick@andestech.com>]

When fit image boots from ram, the payload will
be prepared in the address of SPL_LOAD_FIT_ADDRESS.
In spl fit generic flow, it will malloc another
memory address and copy whole fit image to this
malloc address.  But it is un-necessary for booting
from RAM.

This patch improves this flow by declare the
board_spl_fit_buffer_addr() to replace the original one.
The larger image size (eq: Kernel Image 10~20MB), it
can save more booting time.

Also enhance memcpy function by checking source and
destination address. If they are the same address,
just return and don't copy data anymore.

Signed-off-by: Rick Chen <rick@andestech.com>
---
Changes in v2
 - Move spl.c to board level instead of arch level
---
 arch/riscv/cpu/ax25/Makefile |  1 +
 arch/riscv/cpu/ax25/spl.c    | 31 +++++++++++++++++++++++++++++++
 arch/riscv/lib/memcpy.S      |  2 ++
 3 files changed, 34 insertions(+)
 create mode 100644 arch/riscv/cpu/ax25/spl.c

diff --git a/arch/riscv/cpu/ax25/Makefile b/arch/riscv/cpu/ax25/Makefile
index 318baccb09..f1c21eadd4 100644
--- a/arch/riscv/cpu/ax25/Makefile
+++ b/arch/riscv/cpu/ax25/Makefile
@@ -5,3 +5,4 @@
 
 obj-y	:= cpu.o
 obj-y	+= cache.o
+obj-y += spl.o
diff --git a/arch/riscv/cpu/ax25/spl.c b/arch/riscv/cpu/ax25/spl.c
new file mode 100644
index 0000000000..6bf357d26d
--- /dev/null
+++ b/arch/riscv/cpu/ax25/spl.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2023 Andes Technology Corporation
+ * Rick Chen, Andes Technology Corporation <rick@andestech.com>
+ */
+#include <common.h>
+#include <cpu_func.h>
+#include <hang.h>
+#include <init.h>
+#include <log.h>
+#include <spl.h>
+#include <asm/global_data.h>
+#include <asm/system.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#if CONFIG_IS_ENABLED(RAM_SUPPORT)
+struct legacy_img_hdr *spl_get_load_buffer(ssize_t offset, size_t size)
+{
+	return (void *)(CONFIG_SPL_LOAD_FIT_ADDRESS + offset);
+}
+
+void *board_spl_fit_buffer_addr(ulong fit_size, int sectors, int bl_len)
+{
+	void *buf;
+
+	buf = spl_get_load_buffer(0, sectors * bl_len);
+
+	return buf;
+}
+#endif
diff --git a/arch/riscv/lib/memcpy.S b/arch/riscv/lib/memcpy.S
index 00672c19ad..9884077c93 100644
--- a/arch/riscv/lib/memcpy.S
+++ b/arch/riscv/lib/memcpy.S
@@ -9,6 +9,7 @@
 /* void *memcpy(void *, const void *, size_t) */
 ENTRY(__memcpy)
 WEAK(memcpy)
+	beq	a0, a1, .copy_end
 	/* Save for return value */
 	mv	t6, a0
 
@@ -121,6 +122,7 @@ WEAK(memcpy)
 2:
 
 	mv	a0, t6
+.copy_end:
 	ret
 
 .Lmisaligned_word_copy:
-- 
2.17.1