head_dm270.s

针对德州仪器DM270开发板的bootloader,其实现了内核的下载以及文件系统的下载

//
// File: head_dm270.S
//
// (Derived from head-arm-atmel.S and Boot.asm)
//
// Contains the necessary h/w setup specific to the TI DM270 EVM board.
//
// Copyright (C) 2002 RidgeRun, Inc.
// Author: RidgeRun, Inc  <[e-mail]>
//  - Derived from head_dsc21.S, 9/6/02, Gregory Nutt
//  - Derived from head_dsc25.S, 2/19/03, Gregory Nutt
//
//  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  SOFTWARE  IS  PROVIDED  ``AS  IS''  AND   ANY  EXPRESS  OR IMPLIED
//  WARRANTIES,   INCLUDING, BUT NOT  LIMITED  TO, THE IMPLIED WARRANTIES OF
//  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
//  NO  EVENT  SHALL   THE AUTHOR  BE    LIABLE FOR ANY   DIRECT,  INDIRECT,
//  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
//  NOT LIMITED   TO, PROCUREMENT OF  SUBSTITUTE GOODS  OR SERVICES; LOSS OF
//  USE, DATA,  OR PROFITS; OR  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
//  ANY THEORY OF LIABILITY, WHETHER IN  CONTRACT, STRICT LIABILITY, OR TORT
//  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
//  THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
//  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.,
//  675 Mass Ave, Cambridge, MA 02139, USA.
//
// Please report all bugs/problems to the author or <[e-mail]>
//
// key: RRGPLCR (do not remove)
//
	.text
        .align
        .global _start

#define I_BIT        0x80
#define F_BIT        0x40
#define ARM_MODE_SVC 0x13
        
_start:
        // Turn off IRQ/FIQ and put into service mode.
        mov r0, #(ARM_MODE_SVC | I_BIT | F_BIT)
        msr cpsr, r0
      
        // Initialize the board's clocks.
//        bl clock_ini

        // A little something for the onboard flash.
//        bl flash
      
        // Initialize board's SDRAM controller (64MB).
//        bl sdram_ini

        // Setup Relocation register.
        ldr r10, =0x00000000
        
        // Setup Stack
//        ldr sp, =0x00004ff0
         ldr sp, =0x08000

        mov fp, #0
        b   bootstrap
        
// **********************
// Macro regw(add,data)
// **********************
        .macro regw, reg_add, reg_data
        ldr r0, \reg_add
        ldr r1, \reg_data
        strh r1, [r0]       
        .endm

// **************************************
// Setup on-board flash.
// **************************************
flash:          
        regw EMIF_CS0CTRL1, CS0CTRL1_DATA
        regw EMIF_CS0CTRL2, CS0CTRL2_DATA
        mov  pc, lr
                
// **************************************
// CLOCK controller initialize
// **************************************
clock_ini:

        regw    CLKC_PLLA, PLLAOUT_DATA
        regw    CLKC_PLLB, PLLBOUT_DATA
        regw    CLKC_CLKC, CLOCKC_DATA 
        regw    CLKC_DIV, DIV_DATA
        regw    CLKC_SEL, SEL_DATA
        regw    CLOCKC_MOD1, MOD1_DATA
        regw    CLOCKC_MOD2, MOD2_DATA
        regw    CLOCKC_MOD3, MOD3_DATA
        mov  pc, lr

EMIF_CS0CTRL1:    .word 0x30A00
CS0CTRL1_DATA:   .word 0xAAEF
EMIF_CS0CTRL2:    .word 0x30A02
CS0CTRL2_DATA:   .word 0x7221
CLKC_PLLA    :    .word 0x30880
CLKC_PLLB    :    .word 0x30882
CLKC_CLKC    :      .word 0x30884
CLKC_SEL     :       .word 0x30886
CLKC_DIV     :      .word 0x30888
CLOCKC_MOD1:      .word 0x30890
CLOCKC_MOD2:      .word 0x30892
CLOCKC_MOD3:      .word 0x30894
//CLOCKC_DATA:      .word  0x4280
//PLLAOUT_DATA:      .word 0x00E1
//PLLBOUT_DATA:     .word 0x00C1 
//add 2.20
CLOCKC_DATA:      .word  0x4200
PLLAOUT_DATA:      .word 0x80E1
PLLBOUT_DATA:     .word 0x80C1  
SEL_DATA   :       .word 0x1011 
DIV_DATA   :       .word 0x0111  
MOD1_DATA:        .word 0x07FF
MOD2_DATA:        .word 0x01FF
MOD3_DATA:        .word 0x3FFF

// **********************************************************
// Note: These values should stay in sync with linux/kernel.h
// **********************************************************
L_STACK_MAGIC:           .long 0xdeadbeef
L_STACK_UNTOUCHED_MAGIC: .long 0xfeef1ef0