mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-07-30 06:43:45 +09:00
7b8657e2bd
Make sure value in register r0 and r1 is preserved and passed to the board_init_ll() and mxs_common_spl_init() where it can be processed further. The value in r0 can be configured during the BootStream generation to arbitary value, r1 contains pointer to return value from CALL'd function. This patch also clears the value in r0 before returning to BootROM to make sure the BootROM is not confused by this value. Finally, this patch cleans up some comments in the start.S file. Signed-off-by: Marek Vasut <marex@denx.de> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Stefano Babic <sbabic@denx.de>
204 lines
4.7 KiB
ArmAsm
204 lines
4.7 KiB
ArmAsm
/*
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* armboot - Startup Code for ARM926EJS CPU-core
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*
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* Copyright (c) 2003 Texas Instruments
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*
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* ----- Adapted for OMAP1610 OMAP730 from ARM925t code ------
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*
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* Copyright (c) 2001 Marius Groger <mag@sysgo.de>
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* Copyright (c) 2002 Alex Zupke <azu@sysgo.de>
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* Copyright (c) 2002 Gary Jennejohn <garyj@denx.de>
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* Copyright (c) 2003 Richard Woodruff <r-woodruff2@ti.com>
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* Copyright (c) 2003 Kshitij <kshitij@ti.com>
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* Copyright (c) 2010 Albert Aribaud <albert.u.boot@aribaud.net>
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*
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* Change to support call back into iMX28 bootrom
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* Copyright (c) 2011 Marek Vasut <marek.vasut@gmail.com>
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* on behalf of DENX Software Engineering GmbH
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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 <config.h>
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#include <common.h>
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#include <version.h>
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/*
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*************************************************************************
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*
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* Jump vector table as in table 3.1 in [1]
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*
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*************************************************************************
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*/
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.globl _start
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_start:
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b reset
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b undefined_instruction
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b software_interrupt
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b prefetch_abort
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b data_abort
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b not_used
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b irq
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b fiq
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/*
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* Vector table, located at address 0x20.
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* This table allows the code running AFTER SPL, the U-Boot, to install it's
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* interrupt handlers here. The problem is that the U-Boot is loaded into RAM,
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* including it's interrupt vectoring table and the table at 0x0 is still the
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* SPLs. So if interrupt happens in U-Boot, the SPLs interrupt vectoring table
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* is still used.
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*/
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_vt_reset:
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.word _reset
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_vt_undefined_instruction:
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.word _hang
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_vt_software_interrupt:
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.word _hang
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_vt_prefetch_abort:
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.word _hang
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_vt_data_abort:
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.word _hang
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_vt_not_used:
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.word _reset
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_vt_irq:
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.word _hang
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_vt_fiq:
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.word _hang
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reset:
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ldr pc, _vt_reset
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undefined_instruction:
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ldr pc, _vt_undefined_instruction
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software_interrupt:
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ldr pc, _vt_software_interrupt
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prefetch_abort:
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ldr pc, _vt_prefetch_abort
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data_abort:
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ldr pc, _vt_data_abort
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not_used:
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ldr pc, _vt_not_used
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irq:
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ldr pc, _vt_irq
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fiq:
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ldr pc, _vt_fiq
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.balignl 16,0xdeadbeef
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/*
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*************************************************************************
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*
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* Startup Code (reset vector)
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*
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* do important init only if we don't start from memory!
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* setup Memory and board specific bits prior to relocation.
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* relocate armboot to ram
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* setup stack
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*
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*************************************************************************
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*/
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.globl _TEXT_BASE
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_TEXT_BASE:
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#ifdef CONFIG_SPL_TEXT_BASE
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.word CONFIG_SPL_TEXT_BASE
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#else
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.word CONFIG_SYS_TEXT_BASE
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#endif
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/*
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* These are defined in the board-specific linker script.
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* Subtracting _start from them lets the linker put their
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* relative position in the executable instead of leaving
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* them null.
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*/
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.globl _bss_start_ofs
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_bss_start_ofs:
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.word __bss_start - _start
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.globl _bss_end_ofs
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_bss_end_ofs:
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.word __bss_end - _start
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.globl _end_ofs
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_end_ofs:
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.word _end - _start
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#ifdef CONFIG_USE_IRQ
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/* IRQ stack memory (calculated at run-time) */
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.globl IRQ_STACK_START
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IRQ_STACK_START:
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.word 0x0badc0de
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/* IRQ stack memory (calculated at run-time) */
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.globl FIQ_STACK_START
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FIQ_STACK_START:
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.word 0x0badc0de
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#endif
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/* IRQ stack memory (calculated at run-time) + 8 bytes */
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.globl IRQ_STACK_START_IN
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IRQ_STACK_START_IN:
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.word 0x0badc0de
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/*
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* the actual reset code
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*/
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_reset:
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/*
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* Store all registers on old stack pointer, this will allow us later to
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* return to the BootROM and let the BootROM load U-Boot into RAM.
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*
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* WARNING: Register r0 and r1 are used by the BootROM to pass data
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* to the called code. Register r0 will contain arbitrary
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* data that are set in the BootStream. In case this code
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* was started with CALL instruction, register r1 will contain
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* pointer to the return value this function can then set.
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* The code below MUST NOT CHANGE register r0 and r1 !
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*/
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push {r0-r12,r14}
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/* Save control register c1 */
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mrc p15, 0, r2, c1, c0, 0
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push {r2}
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/* Set the cpu to SVC32 mode and store old CPSR register content. */
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mrs r2, cpsr
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push {r2}
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bic r2, r2, #0x1f
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orr r2, r2, #0xd3
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msr cpsr, r2
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bl board_init_ll
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/* Restore BootROM's CPU mode (especially FIQ). */
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pop {r2}
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msr cpsr,r2
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/*
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* Restore c1 register. Especially set exception vector location
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* back to BootROM space which is required by bootrom for USB boot.
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*/
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pop {r2}
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mcr p15, 0, r2, c1, c0, 0
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pop {r0-r12,r14}
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/*
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* In case this code was started by the CALL instruction, the register
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* r0 is examined by the BootROM after this code returns. The value in
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* r0 must be set to 0 to indicate successful return.
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*/
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mov r0, #0
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bx lr
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_hang:
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ldr sp, _TEXT_BASE /* switch to abort stack */
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1:
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bl 1b /* hang and never return */
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