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https://github.com/brain-hackers/u-boot-brain
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db544b9662
Commit 3ff46cc4 fixed exception vectors setting in
the general ARM case, by either copying the exception
and indirect vector tables to normal (0x00000000) or
high (0xFFFF0000) vectors address, or setting VBAR to
U-Boot's base if applicable.
i.MX27 SoC is ARM926E-JS, thus has only normal and
high options, but does not provide RAM at 0xFFFF0000
and has only ROM at 0x00000000; it is therefore not
possible to move or change its exception vectors.
Besides, i.MX27 ROM code does provide an indirect
vectors table but at a non-standard address and with
the reset and reserved vectors missing.
Turn the current vector relocation code into a weak
routine called after relocate_code from crt0, and add
strong version for i.MX27.
Series-Cc: Heiko Schocher <hs@denx.de>
Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
Reviewed-by: Stefano Babic <sbabic@denx.de>
Tested-by: Stefano Babic <sbabic@denx.de>
Tested-by: Philippe Reynes <tremyfr@gmail.com>
Tested-by: Philippe Reynes <tremyfr@yahoo.fr>
141 lines
4.2 KiB
ArmAsm
141 lines
4.2 KiB
ArmAsm
/*
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* crt0 - C-runtime startup Code for ARM U-Boot
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*
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* Copyright (c) 2012 Albert ARIBAUD <albert.u.boot@aribaud.net>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <config.h>
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#include <asm-offsets.h>
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#include <linux/linkage.h>
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/*
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* This file handles the target-independent stages of the U-Boot
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* start-up where a C runtime environment is needed. Its entry point
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* is _main and is branched into from the target's start.S file.
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*
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* _main execution sequence is:
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*
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* 1. Set up initial environment for calling board_init_f().
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* This environment only provides a stack and a place to store
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* the GD ('global data') structure, both located in some readily
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* available RAM (SRAM, locked cache...). In this context, VARIABLE
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* global data, initialized or not (BSS), are UNAVAILABLE; only
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* CONSTANT initialized data are available.
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*
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* 2. Call board_init_f(). This function prepares the hardware for
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* execution from system RAM (DRAM, DDR...) As system RAM may not
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* be available yet, , board_init_f() must use the current GD to
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* store any data which must be passed on to later stages. These
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* data include the relocation destination, the future stack, and
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* the future GD location.
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*
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* (the following applies only to non-SPL builds)
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*
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* 3. Set up intermediate environment where the stack and GD are the
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* ones allocated by board_init_f() in system RAM, but BSS and
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* initialized non-const data are still not available.
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*
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* 4. Call relocate_code(). This function relocates U-Boot from its
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* current location into the relocation destination computed by
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* board_init_f().
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*
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* 5. Set up final environment for calling board_init_r(). This
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* environment has BSS (initialized to 0), initialized non-const
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* data (initialized to their intended value), and stack in system
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* RAM. GD has retained values set by board_init_f(). Some CPUs
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* have some work left to do at this point regarding memory, so
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* call c_runtime_cpu_setup.
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*
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* 6. Branch to board_init_r().
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*/
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/*
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* entry point of crt0 sequence
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*/
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ENTRY(_main)
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/*
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* Set up initial C runtime environment and call board_init_f(0).
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*/
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#if defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
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ldr sp, =(CONFIG_SPL_STACK)
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#else
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ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
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#endif
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bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
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mov r2, sp
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sub sp, sp, #GD_SIZE /* allocate one GD above SP */
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bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
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mov r9, sp /* GD is above SP */
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mov r1, sp
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mov r0, #0
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clr_gd:
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cmp r1, r2 /* while not at end of GD */
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strlo r0, [r1] /* clear 32-bit GD word */
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addlo r1, r1, #4 /* move to next */
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blo clr_gd
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#if defined(CONFIG_SYS_MALLOC_F_LEN) && !defined(CONFIG_SPL_BUILD)
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sub sp, sp, #CONFIG_SYS_MALLOC_F_LEN
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str sp, [r9, #GD_MALLOC_BASE]
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#endif
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/* mov r0, #0 not needed due to above code */
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bl board_init_f
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#if ! defined(CONFIG_SPL_BUILD)
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/*
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* Set up intermediate environment (new sp and gd) and call
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* relocate_code(addr_moni). Trick here is that we'll return
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* 'here' but relocated.
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*/
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ldr sp, [r9, #GD_START_ADDR_SP] /* sp = gd->start_addr_sp */
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bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
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ldr r9, [r9, #GD_BD] /* r9 = gd->bd */
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sub r9, r9, #GD_SIZE /* new GD is below bd */
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adr lr, here
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ldr r0, [r9, #GD_RELOC_OFF] /* r0 = gd->reloc_off */
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add lr, lr, r0
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ldr r0, [r9, #GD_RELOCADDR] /* r0 = gd->relocaddr */
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b relocate_code
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here:
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/*
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* now relocate vectors
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*/
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bl relocate_vectors
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/* Set up final (full) environment */
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bl c_runtime_cpu_setup /* we still call old routine here */
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ldr r0, =__bss_start /* this is auto-relocated! */
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ldr r1, =__bss_end /* this is auto-relocated! */
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mov r2, #0x00000000 /* prepare zero to clear BSS */
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clbss_l:cmp r0, r1 /* while not at end of BSS */
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strlo r2, [r0] /* clear 32-bit BSS word */
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addlo r0, r0, #4 /* move to next */
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blo clbss_l
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bl coloured_LED_init
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bl red_led_on
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/* call board_init_r(gd_t *id, ulong dest_addr) */
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mov r0, r9 /* gd_t */
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ldr r1, [r9, #GD_RELOCADDR] /* dest_addr */
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/* call board_init_r */
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ldr pc, =board_init_r /* this is auto-relocated! */
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/* we should not return here. */
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#endif
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ENDPROC(_main)
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