mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-05 11:00:15 +00:00
e05e5de7fa
Move all the C runtime setup code from every start.S in arch/arm into arch/arm/lib/crt0.S. This covers the code sequence from setting up the initial stack to calling into board_init_r(). Also, rewrite the C runtime setup and make functions board_init_*() and relocate_code() behave according to normal C semantics (no jumping across the C stack any more, etc). Some SPL targets had to be touched because they use start.S explicitly or for some reason; the relevant maintainers and custodians are cc:ed. Signed-off-by: Albert ARIBAUD <albert.u.boot@aribaud.net>
173 lines
5 KiB
ArmAsm
173 lines
5 KiB
ArmAsm
/*
|
|
* crt0 - C-runtime startup Code for ARM U-Boot
|
|
*
|
|
* Copyright (c) 2012 Albert ARIBAUD <albert.u.boot@aribaud.net>
|
|
*
|
|
* See file CREDITS for list of people who contributed to this
|
|
* project.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation; either version 2 of
|
|
* the License, or (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
|
|
* MA 02111-1307 USA
|
|
*/
|
|
|
|
#include <config.h>
|
|
#include <asm-offsets.h>
|
|
|
|
/*
|
|
* This file handles the target-independent stages of the U-Boot
|
|
* start-up where a C runtime environment is needed. Its entry point
|
|
* is _main and is branched into from the target's start.S file.
|
|
*
|
|
* _main execution sequence is:
|
|
*
|
|
* 1. Set up initial environment for calling board_init_f().
|
|
* This environment only provides a stack and a place to store
|
|
* the GD ('global data') structure, both located in some readily
|
|
* available RAM (SRAM, locked cache...). In this context, VARIABLE
|
|
* global data, initialized or not (BSS), are UNAVAILABLE; only
|
|
* CONSTANT initialized data are available.
|
|
*
|
|
* 2. Call board_init_f(). This function prepares the hardware for
|
|
* execution from system RAM (DRAM, DDR...) As system RAM may not
|
|
* be available yet, , board_init_f() must use the current GD to
|
|
* store any data which must be passed on to later stages. These
|
|
* data include the relocation destination, the future stack, and
|
|
* the future GD location.
|
|
*
|
|
* (the following applies only to non-SPL builds)
|
|
*
|
|
* 3. Set up intermediate environment where the stack and GD are the
|
|
* ones allocated by board_init_f() in system RAM, but BSS and
|
|
* initialized non-const data are still not available.
|
|
*
|
|
* 4. Call relocate_code(). This function relocates U-Boot from its
|
|
* current location into the relocation destination computed by
|
|
* board_init_f().
|
|
*
|
|
* 5. Set up final environment for calling board_init_r(). This
|
|
* environment has BSS (initialized to 0), initialized non-const
|
|
* data (initialized to their intended value), and stack in system
|
|
* RAM. GD has retained values set by board_init_f(). Some CPUs
|
|
* have some work left to do at this point regarding memory, so
|
|
* call c_runtime_cpu_setup.
|
|
*
|
|
* 6. Branch to either nand_boot() or board_init_r().
|
|
*/
|
|
|
|
/*
|
|
* declare nand_boot() or board_init_r() to jump to at end of crt0
|
|
*/
|
|
|
|
#if defined(CONFIG_NAND_SPL)
|
|
|
|
.globl nand_boot
|
|
|
|
#elif ! defined(CONFIG_SPL_BUILD)
|
|
|
|
.globl board_init_r
|
|
|
|
#endif
|
|
|
|
/*
|
|
* start and end of BSS
|
|
*/
|
|
|
|
.globl __bss_start
|
|
.globl __bss_end__
|
|
|
|
/*
|
|
* entry point of crt0 sequence
|
|
*/
|
|
|
|
.global _main
|
|
|
|
_main:
|
|
|
|
/*
|
|
* Set up initial C runtime environment and call board_init_f(0).
|
|
*/
|
|
|
|
#if defined(CONFIG_NAND_SPL)
|
|
/* deprecated, use instead CONFIG_SPL_BUILD */
|
|
ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
|
|
#elif defined(CONFIG_SPL_BUILD) && defined(CONFIG_SPL_STACK)
|
|
ldr sp, =(CONFIG_SPL_STACK)
|
|
#else
|
|
ldr sp, =(CONFIG_SYS_INIT_SP_ADDR)
|
|
#endif
|
|
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
|
|
sub sp, #GD_SIZE /* allocate one GD above SP */
|
|
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
|
|
mov r8, sp /* GD is above SP */
|
|
mov r0, #0
|
|
bl board_init_f
|
|
|
|
#if ! defined(CONFIG_SPL_BUILD)
|
|
|
|
/*
|
|
* Set up intermediate environment (new sp and gd) and call
|
|
* relocate_code(addr_sp, gd, addr_moni). Trick here is that
|
|
* we'll return 'here' but relocated.
|
|
*/
|
|
|
|
ldr sp, [r8, #GD_START_ADDR_SP] /* r8 = gd->start_addr_sp */
|
|
bic sp, sp, #7 /* 8-byte alignment for ABI compliance */
|
|
ldr r8, [r8, #GD_BD] /* r8 = gd->bd */
|
|
sub r8, r8, #GD_SIZE /* new GD is below bd */
|
|
|
|
adr lr, here
|
|
ldr r0, [r8, #GD_RELOC_OFF] /* lr = gd->start_addr_sp */
|
|
add lr, lr, r0
|
|
ldr r0, [r8, #GD_START_ADDR_SP] /* r0 = gd->start_addr_sp */
|
|
mov r1, r8 /* r1 = gd */
|
|
ldr r2, [r8, #GD_RELOCADDR] /* r2 = gd->relocaddr */
|
|
b relocate_code
|
|
here:
|
|
|
|
/* Set up final (full) environment */
|
|
|
|
bl c_runtime_cpu_setup /* we still call old routine here */
|
|
|
|
ldr r0, =__bss_start /* this is auto-relocated! */
|
|
ldr r1, =__bss_end__ /* this is auto-relocated! */
|
|
|
|
mov r2, #0x00000000 /* prepare zero to clear BSS */
|
|
|
|
clbss_l:cmp r0, r1 /* while not at end of BSS */
|
|
strlo r2, [r0] /* clear 32-bit BSS word */
|
|
addlo r0, r0, #4 /* move to next */
|
|
blo clbss_l
|
|
|
|
bl coloured_LED_init
|
|
bl red_led_on
|
|
|
|
#if defined(CONFIG_NAND_SPL)
|
|
|
|
/* call _nand_boot() */
|
|
ldr pc, =nand_boot
|
|
|
|
#else
|
|
|
|
/* call board_init_r(gd_t *id, ulong dest_addr) */
|
|
mov r0, r8 /* gd_t */
|
|
ldr r1, [r8, #GD_RELOCADDR] /* dest_addr */
|
|
/* call board_init_r */
|
|
ldr pc, =board_init_r /* this is auto-relocated! */
|
|
|
|
#endif
|
|
|
|
/* we should not return here. */
|
|
|
|
#endif
|