[PATCH 4/7] firmware: fw_base.S: call fw_dynamic_append_boot_args on cold boot

[Zong Li]

When building the FW_DYNAMIC_APPEND firmware type, the previous booting
stage jumps directly to _start without setting up a0/a1/a2. Add a single
guarded call at the very top of the cold _start path to
fw_dynamic_append_boot_args(), whose implementation lives in
fw_dynamic_append.S.

The call is wrapped in #ifdef FW_DYNAMIC_APPEND, which is only defined by
fw_dynamic_append.S, so FW_DYNAMIC, FW_JUMP and FW_PAYLOAD compile and
behave exactly as before. Only the cold boot path is touched, secondary
HARTs continue to enter through _start_warm.

Signed-off-by: Zong Li <zong.li at sifive.com>
---
 firmware/fw_base.S | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index 0c5c65c1..91a17efb 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -46,6 +46,17 @@
 	.globl _start
 	.globl _start_warm
 _start:
+#ifdef FW_DYNAMIC_APPEND
+	/*
+	 * FW_DYNAMIC_APPEND entry fixup (cold boot path only).
+	 *
+	 * For this firmware type the previous booting stage does NOT pass the
+	 * usual a0=hartid, a1=dtb, a2=fw_dynamic_info arguments. It merely
+	 * patches the fw_dynamic_info structure appended at the tail of this
+	 * binary (right before .bss, see fw_base.ldS) and jumps here.
+	 */
+	call	fw_dynamic_append_boot_args
+#endif
 	/* Find preferred boot HART id */
 	MOV_3R	s0, a0, s1, a1, s2, a2
 	call	fw_boot_hart
-- 
2.43.7