u-boot/arch/arm/cpu/arm720t/start.S
Simon Glass 1c2d2727d1 arm: arm720t: Support CONFIG_SKIP_LOWLEVEL_INIT_ONLY
This option allows skipping the call to lowlevel() while still performing
CP15 init. Support this on ARM720T so it can be used with Tegra.

Signed-off-by: Simon Glass <sjg@chromium.org>
2017-06-09 13:39:31 -06:00

80 lines
1.6 KiB
ArmAsm

/*
* armboot - Startup Code for ARM720 CPU-core
*
* Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
* Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <asm-offsets.h>
#include <config.h>
/*
*************************************************************************
*
* Startup Code (reset vector)
*
* do important init only if we don't start from RAM!
* relocate armboot to ram
* setup stack
* jump to second stage
*
*************************************************************************
*/
.globl reset
reset:
/*
* set the cpu to SVC32 mode
*/
mrs r0,cpsr
bic r0,r0,#0x1f
orr r0,r0,#0xd3
msr cpsr,r0
/*
* we do sys-critical inits only at reboot,
* not when booting from ram!
*/
#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) && \
!defined(CONFIG_SKIP_LOWLEVEL_INIT_ONLY)
bl cpu_init_crit
#endif
bl _main
/*------------------------------------------------------------------------------*/
.globl c_runtime_cpu_setup
c_runtime_cpu_setup:
mov pc, lr
/*
*************************************************************************
*
* CPU_init_critical registers
*
* setup important registers
* setup memory timing
*
*************************************************************************
*/
#if !defined(CONFIG_SKIP_LOWLEVEL_INIT) && \
!defined(CONFIG_SKIP_LOWLEVEL_INIT_ONLY)
cpu_init_crit:
mov ip, lr
/*
* before relocating, we have to setup RAM timing
* because memory timing is board-dependent, you will
* find a lowlevel_init.S in your board directory.
*/
bl lowlevel_init
mov lr, ip
mov pc, lr
#endif /* CONFIG_SKIP_LOWLEVEL_INIT */