mxc_spl_startup.s

i.mx31 3DS平台Nandboot引导程序源码

/*
 * Copyright 2004-2006 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 * 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
 */

/*!
 * @file spl/mxc_spl_startup.S
 * 
 * @brief Assembly code required to initialize the stack for Secondary Program 
 * Loader.
 * 
 * @ingroup NANDboot
 */
#ifdef MX21
#define STACK_ADDR      0xC0008000

#else
#define STACK_ADDR      0x80004000
#endif
/*!
 * This is the first assembly routine called when NANDboot starts executing.
 *
 */
init:
	
        ldr     sp,=STACK_ADDR
        bl      mxcnb_spl

        .global         jump_to_kernel

/*!
 * This assembly function is called by SPL to load the program counter with 
 * Linux kernel image starting address. Using this function SPL passes the 
 * control to Linux kernel. 
 * SPL stores following data required by Linux kernel into the registers 
 * before executing the kernel through the function parameters.
 * This function is used with following prototype
 * void JumpToKernel(int reg_ro, int mach_arch, int pcmdline, int jaddr)
 *
 * @param reg_ro        stores reg r0 = 0
 * @param mach_arch     stores reg r1 = machine architecture number
 * @param pcmdline      stores reg r2 = pointer to command line
 * @param jaddr         stores reg r3 = jump address
 *
 */
jump_to_kernel:
        /* jump to the first instruction of the Linux kernel */
        mov     pc, r3