[PATCH 1/2] lib: sbi: Introduce early hart initialization scheme

[Leo Yu-Chi Liang]

Referencing U-Boot (edd9ad81 riscv: cpu: Add callback to init each core)
Introduce a callback function for each hart to do its own initialization
as early as possible.

Signed-off-by: Leo Yu-Chi Liang <ycliang at andestech.com>
---
 firmware/fw_base.S | 6 ++++++
 lib/sbi/sbi_init.c | 4 ++++
 2 files changed, 10 insertions(+)

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index 1569e60..dfbe7d7 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -47,6 +47,12 @@
 	.globl _start
 	.globl _start_warm
 _start:
+	/* Setup temporary stack */
+	lla	s4, _fw_end
+	li	s5, (SBI_SCRATCH_SIZE * 2)
+	add	sp, s4, s5
+	/* call harts_early_init */
+	call harts_early_init
 	/* Find preferred boot HART id */
 	MOV_3R	s0, a0, s1, a1, s2, a2
 	call	fw_boot_hart
diff --git a/lib/sbi/sbi_init.c b/lib/sbi/sbi_init.c
index 6ef8742..02acac0 100644
--- a/lib/sbi/sbi_init.c
+++ b/lib/sbi/sbi_init.c
@@ -536,3 +536,7 @@ void __noreturn sbi_exit(struct sbi_scratch *scratch)
 
 	sbi_hsm_exit(scratch);
 }
+
+__attribute__((weak)) void harts_early_init(void)
+{
+}
-- 
2.17.0