firmware: fw_base: Introduce optional fw_platform_init()

We add optional fw_platform_init() function which will allow
platform specific code to update "struct sbi_platform platform"
before it is used.

The fw_platform_init() can be a regular C function so before
callint it we:
1. zero-out BSS section
2. Setup temporary trap handler to catch bugs
3. Setup temporary stack pointer

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
This commit is contained in:
Anup Patel 2020-04-26 14:31:28 +05:30 committed by Anup Patel
parent 7cc6fa4d8a
commit 4d063538f0

View file

@ -160,6 +160,32 @@ _relocate_done:
li ra, 0
call _reset_regs
/* Zero-out BSS */
la s4, _bss_start
la s5, _bss_end
_bss_zero:
REG_S zero, (s4)
add s4, s4, __SIZEOF_POINTER__
blt s4, s5, _bss_zero
/* Setup temporary trap handler */
la s4, _start_hang
csrw CSR_MTVEC, s4
/* Setup temporary stack */
la s4, _fw_end
li s5, (SBI_SCRATCH_SIZE * 2)
add sp, s4, s5
/*
* Initialize platform
* Note: The a0 to a4 registers passed to the
* firmware are parameters to this function.
*/
MOV_5R s0, a0, s1, a1, s2, a2, s3, a3, s4, a4
call fw_platform_init
MOV_5R a0, s0, a1, s1, a2, s2, a3, s3, a4, s4
/* Allow main firmware to save info */
MOV_5R s0, a0, s1, a1, s2, a2, s3, a3, s4, a4
call fw_save_info
@ -245,14 +271,6 @@ _scratch_init:
add t1, t1, t2
blt t1, s7, _scratch_init
/* Zero-out BSS */
la a4, _bss_start
la a5, _bss_end
_bss_zero:
REG_S zero, (a4)
add a4, a4, __SIZEOF_POINTER__
blt a4, a5, _bss_zero
/* Override pervious arg1 */
MOV_3R s0, a0, s1, a1, s2, a2
call fw_prev_arg1
@ -454,6 +472,13 @@ _start_hang:
wfi
j _start_hang
.section .entry, "ax", %progbits
.align 3
.globl fw_platform_init
.weak fw_platform_init
fw_platform_init:
ret
.section .entry, "ax", %progbits
.align 3
.globl _trap_handler