u-boot/arch/arm/cpu/sa1100/start.S
Simon Glass b5bd09820c arm: Allow skipping of low-level init with I-cache on
At present CONFIG_SKIP_LOWLEVEL_INIT prevents U-Boot from calling
lowlevel_init(). This means that the instruction cache is not enabled and
the board runs very slowly.

What is really needed in many cases is to skip the call to lowlevel_init()
but still perform CP15 init. Add an option to handle this.

Reviewed-by: Heiko Schocher <hs@denx.de>
Tested-on: smartweb, corvus, taurus, axm
Tested-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Joe Hershberger <joe.hershberger@ni.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>
2016-06-12 23:49:38 +02:00

127 lines
2.5 KiB
ArmAsm

/*
* armboot - Startup Code for SA1100 CPU
*
* Copyright (C) 1998 Dan Malek <dmalek@jlc.net>
* Copyright (C) 1999 Magnus Damm <kieraypc01.p.y.kie.era.ericsson.se>
* Copyright (C) 2000 Wolfgang Denk <wd@denx.de>
* Copyright (c) 2001 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 memory!
* 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!
*/
#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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
*
*************************************************************************
*/
/* Interrupt-Controller base address */
IC_BASE: .word 0x90050000
#define ICMR 0x04
/* Reset-Controller */
RST_BASE: .word 0x90030000
#define RSRR 0x00
#define RCSR 0x04
/* PWR */
PWR_BASE: .word 0x90020000
#define PSPR 0x08
#define PPCR 0x14
cpuspeed: .word CONFIG_SYS_CPUSPEED
cpu_init_crit:
/*
* mask all IRQs
*/
ldr r0, IC_BASE
mov r1, #0x00
str r1, [r0, #ICMR]
/* set clock speed */
ldr r0, PWR_BASE
ldr r1, cpuspeed
str r1, [r0, #PPCR]
#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY
/*
* before relocating, we have to setup RAM timing
* because memory timing is board-dependend, you will
* find a lowlevel_init.S in your board directory.
*/
mov ip, lr
bl lowlevel_init
mov lr, ip
#endif
/*
* disable MMU stuff and enable I-cache
*/
mrc p15,0,r0,c1,c0
bic r0, r0, #0x00002000 @ clear bit 13 (X)
bic r0, r0, #0x0000000f @ clear bits 3-0 (WCAM)
orr r0, r0, #0x00001000 @ set bit 12 (I) Icache
orr r0, r0, #0x00000002 @ set bit 1 (A) Align
mcr p15,0,r0,c1,c0
/*
* flush v4 I/D caches
*/
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
mov pc, lr