arch/arm/lib/crt0.S - uboot/armada - Git at Google

 /*
  *  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
  */

 #ifdef CONFIG_MACH_AVANTA_LP_FPGA
 .globl _board_init_f_link_addr
 _board_init_f_link_addr:
 	.word board_init_f

 .globl _start_link_val2
 _start_link_val2:
 	.word _main
 #endif

 .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
 #ifdef CONFIG_MACH_AVANTA_LP_FPGA
 	/* Instead of 'bl' use 'ldr pc, addr'
 	 * Rationale: 'bl' is PC-relative, => not appropriate when running
 	 * from Flash, because .text is already copied into RAM, so, flow has
 	 * to jump to RAM (meaning: linker-based symbol address).
 	 */
 	mov	r14, pc
 	ldr	pc, _board_init_f_link_addr
 #else
 	bl	board_init_f
 #endif

 #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

 /* additional test if running from flash (FPGA) */
 #ifdef CONFIG_MACH_AVANTA_LP_FPGA
 	adr	r0, _main		/* r0 <- current position of code */
 	ldr	r1, _start_link_val2	/* r1 =  current position  offset relative to code start :test if we run from flash or RAM */
 	cmp	r0, r1			/* if not equal we run from FLASH -> r14 offset correction needed */
 	beq	no_correction

 	sub	r0,  r0,  r1		/* r0 = flash base */
 	sub 	r14, r14, r0		/* r14 = fixed return address after code relocation */
 #endif
 /* additional test if running from flash (FPGA) */

 no_correction:
 	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
	/*
	* 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
	*/

	#ifdef CONFIG_MACH_AVANTA_LP_FPGA
	.globl _board_init_f_link_addr
	_board_init_f_link_addr:
	.word board_init_f

	.globl _start_link_val2
	_start_link_val2:
	.word _main
	#endif

	.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
	#ifdef CONFIG_MACH_AVANTA_LP_FPGA
	/* Instead of 'bl' use 'ldr pc, addr'
	* Rationale: 'bl' is PC-relative, => not appropriate when running
	* from Flash, because .text is already copied into RAM, so, flow has
	* to jump to RAM (meaning: linker-based symbol address).
	*/
	mov r14, pc
	ldr pc, _board_init_f_link_addr
	#else
	bl board_init_f
	#endif

	#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

	/* additional test if running from flash (FPGA) */
	#ifdef CONFIG_MACH_AVANTA_LP_FPGA
	adr r0, _main /* r0 <- current position of code */
	ldr r1, _start_link_val2 /* r1 = current position offset relative to code start :test if we run from flash or RAM */
	cmp r0, r1 /* if not equal we run from FLASH -> r14 offset correction needed */
	beq no_correction

	sub r0, r0, r1 /* r0 = flash base */
	sub r14, r14, r0 /* r14 = fixed return address after code relocation */
	#endif
	/* additional test if running from flash (FPGA) */

	no_correction:
	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