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https://source.denx.de/u-boot/u-boot.git
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b5bd09820c
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>
151 lines
3.1 KiB
ArmAsm
151 lines
3.1 KiB
ArmAsm
/*
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* armboot - Startup Code for ARM920 CPU-core
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*
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* Copyright (c) 2001 Marius Gröger <mag@sysgo.de>
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* Copyright (c) 2002 Alex Züpke <azu@sysgo.de>
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* Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <asm-offsets.h>
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#include <common.h>
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#include <config.h>
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/*
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*************************************************************************
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*
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* Startup Code (called from the ARM reset exception vector)
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*
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* do important init only if we don't start from memory!
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* relocate armboot to ram
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* setup stack
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* jump to second stage
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*
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*************************************************************************
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*/
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.globl reset
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reset:
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/*
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* set the cpu to SVC32 mode
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*/
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mrs r0, cpsr
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bic r0, r0, #0x1f
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orr r0, r0, #0xd3
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msr cpsr, r0
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#if defined(CONFIG_AT91RM9200DK) || defined(CONFIG_AT91RM9200EK)
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/*
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* relocate exception table
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*/
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ldr r0, =_start
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ldr r1, =0x0
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mov r2, #16
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copyex:
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subs r2, r2, #1
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ldr r3, [r0], #4
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str r3, [r1], #4
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bne copyex
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#endif
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#ifdef CONFIG_S3C24X0
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/* turn off the watchdog */
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# if defined(CONFIG_S3C2400)
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# define pWTCON 0x15300000
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# define INTMSK 0x14400008 /* Interrupt-Controller base addresses */
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# define CLKDIVN 0x14800014 /* clock divisor register */
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#else
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# define pWTCON 0x53000000
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# define INTMSK 0x4A000008 /* Interrupt-Controller base addresses */
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# define INTSUBMSK 0x4A00001C
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# define CLKDIVN 0x4C000014 /* clock divisor register */
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# endif
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ldr r0, =pWTCON
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mov r1, #0x0
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str r1, [r0]
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/*
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* mask all IRQs by setting all bits in the INTMR - default
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*/
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mov r1, #0xffffffff
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ldr r0, =INTMSK
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str r1, [r0]
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# if defined(CONFIG_S3C2410)
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ldr r1, =0x3ff
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ldr r0, =INTSUBMSK
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str r1, [r0]
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# endif
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/* FCLK:HCLK:PCLK = 1:2:4 */
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/* default FCLK is 120 MHz ! */
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ldr r0, =CLKDIVN
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mov r1, #3
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str r1, [r0]
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#endif /* CONFIG_S3C24X0 */
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/*
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* we do sys-critical inits only at reboot,
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* not when booting from ram!
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*/
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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bl cpu_init_crit
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#endif
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bl _main
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/*------------------------------------------------------------------------------*/
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.globl c_runtime_cpu_setup
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c_runtime_cpu_setup:
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mov pc, lr
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/*
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*************************************************************************
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*
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* CPU_init_critical registers
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*
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* setup important registers
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* setup memory timing
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*
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*************************************************************************
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*/
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT
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cpu_init_crit:
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/*
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* flush v4 I/D caches
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*/
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mov r0, #0
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mcr p15, 0, r0, c7, c7, 0 /* flush v3/v4 cache */
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mcr p15, 0, r0, c8, c7, 0 /* flush v4 TLB */
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/*
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* disable MMU stuff and caches
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*/
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mrc p15, 0, r0, c1, c0, 0
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bic r0, r0, #0x00002300 @ clear bits 13, 9:8 (--V- --RS)
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bic r0, r0, #0x00000087 @ clear bits 7, 2:0 (B--- -CAM)
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orr r0, r0, #0x00000002 @ set bit 1 (A) Align
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orr r0, r0, #0x00001000 @ set bit 12 (I) I-Cache
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mcr p15, 0, r0, c1, c0, 0
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#ifndef CONFIG_SKIP_LOWLEVEL_INIT_ONLY
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/*
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* before relocating, we have to setup RAM timing
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* because memory timing is board-dependend, you will
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* find a lowlevel_init.S in your board directory.
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*/
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mov ip, lr
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bl lowlevel_init
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mov lr, ip
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#endif
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mov pc, lr
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#endif /* CONFIG_SKIP_LOWLEVEL_INIT */
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