Hello Albert,
On 11/4/2012 5:02 PM, Albert ARIBAUD wrote:
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 isetting 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 exolicitly or for some reason; the relevant maintainers and custodians are cc:ed.
Signed-off-by: Albert ARIBAUDalbert.u.boot@aribaud.net
Changes in v2:
- moved description from cover letter to patch commit msg
- added note about tests in the cover letter
- fixed baords with CONFIG_SPL but not CONFIG_SPL_STACK
<snip>
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S new file mode 100644 index 0000000..fd6bd92 --- /dev/null +++ b/arch/arm/lib/crt0.S @@ -0,0 +1,180 @@ +/*
- crt0 - C-runtime startup Code for ARM U-Boot
- Copyright (c) 2012 Albert ARIBAUDalbert.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:
- 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. In this context, VARIABLE
- global data, initialized or not (BSS), are UNAVAILABLE; only
- CONSTANT initialized data are available.
- Call board_init_f(). This function prepares the hardware for
- execution from DDR. As DDR may not be available, board_init_f()
- must use GD to store any data which must be passed on to later,
- stages, including the reloction destination and the new stack
- pointer address, below which the stack resides and above it the
- new GD resides.
- Set up intermediate environment where the stack and GD are the
- ones allocated by board_init_f() in DDR, but BSS and initialized
- non-const data are still not available.
- Call relocate_code(). This function relocates U-Boot from its
- current location into the relocation destination computed by
- board_init_f().
- 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 DDR.
- GD has but retained values set by board_init_f(). Some CPUs
- have some work to do at this point, so call c_runtime_cpu_setup.
- Call noard_init_r(). If the function returns, reset the board.
- */
s/noard_init_r/board_init_r
+/*
- offset of the nand_boot() function for SPL crt
- */
+#if defined(CONFIG_NAND_SPL)
+.globl nand_boot +_nand_boot:
- .word nand_boot
+#elif ! defined(CONFIG_SPL_BUILD)
+/*
- offset of the board_init_r() function for non-SPL crt
- */
+.globl board_init_r +_board_init_r:
- .word 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 */
- mov r8, sp /* GD is above SP */
- mov r0, #0
- bl board_init_f
+/*
- 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 */
- ldr r8, [r8, #GD_BD] /* r8 = gd->bd */
- sub r8, r8, #GD_SIZE /* new GD is below bd */
+#ifndef CONFIG_SPL_BUILD
In some places the other style is used. "!(defined)". Any particular reasons for switching b/w these two styles?
- 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:
+#endif
+/* 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 aotu-relocated! */
s/aotu/auto
Regards, Vikram