u-boot/arch/arm/mach-aspeed/ast2500/lowlevel_init.S
Chia-Wei, Wang 611fe09577 aspeed: ast2500: Add lowlevel_init assembly
The original lowlevel_init function of AST2500 is written
in C. However, the C runtime environment is not ready until
_main execution.

This patch adds the assembly version of the lowlevel_init
function. Additional initialization to DRAM configuration
and LPC reset source are also added.

Signed-off-by: Chia-Wei, Wang <chiawei_wang@aspeedtech.com>
2020-08-14 09:46:40 -04:00

41 lines
862 B
ArmAsm

/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (C) ASPEED Technology Inc.
*/
#include <asm/arch/scu_ast2500.h>
/* registers for low level init */
#define SCU_PROT_KEY 0x1e6e2000
#define SCU_VGA_HANDSHAKE 0x1e6e2040
#define SCU_HW_STRAP 0x1e6e2070
#define SCU_HW_STRAP_CLR 0x1e6e207c
#define WDT3_CTRL 0x1e78504c
.global lowlevel_init
lowlevel_init:
/* unlock SCU */
ldr r0, =SCU_PROT_KEY
ldr r1, =SCU_UNLOCK_VALUE
str r1, [r0]
/* set BMC FW as DRAM initializer */
ldr r0, =SCU_VGA_HANDSHAKE
ldr r1, [r0]
orr r1, #0x80
str r1, [r0]
/* set PERST# as LPC reset source if eSPI mode is enabled*/
ldr r0, =SCU_HW_STRAP
ldr r1, [r0]
tst r1, #(0x1 << 25)
ldrne r0, =SCU_HW_STRAP_CLR
movne r1, #(0x1 << 14)
strne r1, [r0]
/* disable WDT3 for SPI 3/4 bytes auto-detection */
ldr r0, =WDT3_CTRL
mov r1, #0x0
str r1, [r0]
mov pc, lr