sc520_asm.s

AT91RM9200的完整启动代码：包括loader, boot及U-boot三部分均已编译通过！欢迎下载使用！

/*
 * (C) Copyright 2002
 * Daniel Engstr鰉, Omicron Ceti AB <[e-mail]>.
 *
 * 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
 */

/* This file is largely based on code obtned from AMD. AMD's original
 * copyright is included below 
 */

/*
 *  =============================================================================
 *                                                                              
 *   Copyright 1999 Advanced Micro Devices, Inc.                                
 *                                                                              
 *  This software is the property of Advanced Micro Devices, Inc  (AMD)  which 
 *  specifically grants the user the right to modify, use and distribute this 
 *  software provided this COPYRIGHT NOTICE is not removed or altered.  All 
 *  other rights are reserved by AMD.                                                       
 *                                                                             
 *  THE MATERIALS ARE PROVIDED "AS IS" WITHOUT ANY EXPRESS OR IMPLIED WARRANTY 
 *  OF ANY KIND INCLUDING WARRANTIES OF MERCHANTABILITY, NONINFRINGEMENT OF 
 *  THIRD-PARTY INTELLECTUAL PROPERTY, OR FITNESS FOR ANY PARTICULAR PURPOSE.
 *  IN NO EVENT SHALL AMD OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER
 *  (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS, BUSINESS
 *  INTERRUPTION, LOSS OF INFORMAITON) ARISING OUT OF THE USE OF OR INABILITY
 *  TO USE THE MATERIALS, EVEN IF AMD HAS BEEN ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGES.  BECAUSE SOME JURSIDICTIONS PROHIBIT THE EXCLUSION OR
 *  LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES, THE ABOVE
 *  LIMITATION MAY NOT APPLY TO YOU.
 * 
 *  AMD does not assume any responsibility for any errors that may appear in
 *  the Materials nor any responsibility to support or update the Materials.
 *  AMD retains the right to make changes to its test specifications at any
 *  time, without notice.
 * 
 *  So that all may benefit from your experience, please report  any  problems 
 *  or suggestions about this software back to AMD.  Please include your name, 
 *  company,  telephone number,  AMD product requiring support and question or 
 *  problem encountered.                                                       
 *                                                                             
 *  Advanced Micro Devices, Inc.         Worldwide support and contact           
 *  Embedded Processor Division            information available at:               
 *  Systems Engineering                       [e-mail]
 *  5204 E. Ben White Blvd.                          -or-
 *  Austin, TX 78741                http://www.amd.com/html/support/techsup.html
 *  ============================================================================
 */


/*******************************************************************************
 *	 AUTHOR      : Buddy Fey - Original. 
 *******************************************************************************
 */


/*******************************************************************************
 *       FUNCTIONAL DESCRIPTION:
 * This routine is called to autodetect the geometry of the DRAM.
 *
 * This routine is called to determine the number of column bits for the DRAM
 * devices in this external bank. This routine assumes that the external bank
 * has been configured for an 11-bit column and for 4 internal banks. This gives
 * us the maximum address reach in memory. By writing a test value to the max
 * address and locating where it aliases to, we can determine the number of valid
 * column bits.
 *
 * This routine is called to determine the number of internal banks each DRAM
 * device has. The external bank (under test) is configured for maximum reach
 * with 11-bit columns and 4 internal banks. This routine will write to a max
 * address (BA1 and BA0 = 1) and then read from an address with BA1=0 to see if
 * that column is a "don't care". If BA1 does not affect write/read of data,
 * then this device has only 2 internal banks.
 *
 * This routine is called to determine the ending address for this external
 * bank of SDRAM. We write to a max address with a data value and then disable
 * row address bits looking for "don't care" locations. Each "don't care" bit
 * represents a dividing of the maximum density (128M) by 2. By dividing the
 * maximum of 32 4M chunks in an external bank down by all the "don't care" bits
 * determined during sizing, we set the proper density.
 *
 * WARNINGS.
 * bp must be preserved because it is used for return linkage.
 *
 * EXIT
 * nothing returned - but the memory subsystem is enabled
 *******************************************************************************
 */

#include <config.h>
#ifdef CONFIG_SC520

.section .text
.equ            DRCCTL,     0x0fffef010   /* DRAM control register */
.equ            DRCTMCTL,   0x0fffef012   /* DRAM timing control register */
.equ            DRCCFG,     0x0fffef014   /* DRAM bank configuration register */
.equ            DRCBENDADR, 0x0fffef018   /* DRAM bank ending address register */
.equ            ECCCTL,     0x0fffef020   /* DRAM ECC control register */
.equ            DBCTL,      0x0fffef040   /* DRAM buffer control register */

.equ            CACHELINESZ, 0x00000010   /* size of our cache line (read buffer) */
.equ            COL11_ADR,  0x0e001e00    /* 11 col addrs */
.equ            COL10_ADR,  0x0e000e00    /* 10 col addrs */
.equ            COL09_ADR,  0x0e000600    /*  9 col addrs */
.equ            COL08_ADR,  0x0e000200    /*  8 col addrs */
.equ            ROW14_ADR,  0x0f000000    /* 14 row addrs */
.equ            ROW13_ADR,  0x07000000    /* 13 row addrs */
.equ            ROW12_ADR,  0x03000000    /* 12 row addrs */
.equ            ROW11_ADR,  0x01000000    /* 11 row addrs/also bank switch */
.equ            ROW10_ADR,  0x00000000    /* 10 row addrs/also bank switch */
.equ            COL11_DATA, 0x0b0b0b0b    /* 11 col addrs */
.equ            COL10_DATA, 0x0a0a0a0a    /* 10 col data */
.equ            COL09_DATA, 0x09090909    /*  9 col data */
.equ            COL08_DATA, 0x08080808    /*  8 col data */
.equ            ROW14_DATA, 0x3f3f3f3f    /* 14 row data (MASK) */
.equ            ROW13_DATA, 0x1f1f1f1f    /* 13 row data (MASK) */
.equ            ROW12_DATA, 0x0f0f0f0f    /* 12 row data (MASK) */
.equ            ROW11_DATA, 0x07070707    /* 11 row data/also bank switch (MASK) */
.equ            ROW10_DATA, 0xaaaaaaaa    /* 10 row data/also bank switch (MASK) */


 /*
  * initialize dram controller registers
  */
.globl mem_init
mem_init: 
        xorw    %ax,%ax
        movl    $DBCTL, %edi             
	movb     %al, (%edi)             /* disable write buffer */

        movl    $ECCCTL, %edi            
	movb     %al, (%edi)             /* disable ECC */

        movl    $DRCTMCTL, %edi           
        movb    $0x1E,%al                /* Set SDRAM timing for slowest */
	movb     %al, (%edi)

 /*
  * setup loop to do 4 external banks starting with bank 3
  */
        movl    $0xff000000,%eax         /* enable last bank and setup */
        movl    $DRCBENDADR, %edi        /* ending address register */
	movl     %eax, (%edi)

        movl    $DRCCFG, %edi            /* setup */
        movw    $0xbbbb,%ax              /* dram config register for  */
	movw    %ax, (%edi)

 /*
  * issue a NOP to all DRAMs
  */
        movl    $DRCCTL, %edi            /* setup DRAM control register with */
        movb    $0x1,%al                 /* Disable refresh,disable write buffer */ 
	movb     %al, (%edi)
        movl    $CACHELINESZ, %esi       /* just a dummy address to write for */ 
	movw     %ax, (%esi)
 /*
  * delay for 100 usec? 200?
  * ******this is a cludge for now *************
  */
        movw    $100,%cx
sizdelay: 
        loop    sizdelay                 /* we need 100 usec here */
 /***********************************************/

 /*
  * issue all banks precharge
  */
        movb    $0x2,%al                 /* All banks precharge */
	movb     %al, (%edi)
	movw     %ax, (%esi)

 /*
  * issue 2 auto refreshes to all banks 
  */
        movb    $0x4,%al                 /* Auto refresh cmd */
	movb     %al, (%edi)
        movw    $2,%cx
refresh1: 
	movw     %ax, (%esi)
        loop    refresh1

 /*
  * issue LOAD MODE REGISTER command
  */
        movb    $0x3,%al                 /* Load mode register cmd */
	movb     %al, (%edi)
	movw     %ax, (%esi)

 /*
  * issue 8 more auto refreshes to all banks 
  */ 
        movb    $0x4,%al                 /* Auto refresh cmd */
	movb     %al, (%edi)
        movw    $8,%cx
refresh2: 
	movw     %ax, (%esi)
        loop    refresh2

 /*
  * set control register to NORMAL mode 
  */
        movb    $0x0,%al                 /* Normal mode value */
	movb     %al, (%edi)

 /*
  * size dram starting with external bank 3 moving to external bank 0
  */
        movl    $0x3,%ecx                /* start with external bank 3 */

nextbank: 

 /*
  * write col 11 wrap adr
  */
        movl    $COL11_ADR, %esi         /* set address to max col (11) wrap addr */
        movl    $COL11_DATA, %eax        /* pattern for max supported columns(11) */
	movl    %eax, (%esi)             /* write max col pattern at max col adr */
	movl    (%esi), %ebx             /* optional read */
        cmpl    %ebx,%eax                /* to verify write */
        jnz     bad_ram                  /* this ram is bad */
 /*
  * write col 10 wrap adr
  */

        movl    $COL10_ADR, %esi         /* set address to 10 col wrap address */
        movl    $COL10_DATA, %eax        /* pattern for 10 col wrap */
	movl    %eax, (%esi)             /* write 10 col pattern @ 10 col wrap adr */
	movl    (%esi), %ebx             /* optional read */
        cmpl    %ebx,%eax                /* to verify write */
        jnz     bad_ram                  /* this ram is bad */
 /*
  * write col 9 wrap adr
  */
        movl    $COL09_ADR, %esi         /* set address to 9 col wrap address */
        movl    $COL09_DATA, %eax        /* pattern for 9 col wrap */
	movl    %eax, (%esi)             /* write 9 col pattern @ 9 col wrap adr */
	movl    (%esi), %ebx             /* optional read */
        cmpl    %ebx,%eax                /* to verify write */
        jnz     bad_ram                  /* this ram is bad */
 /*
  * write col 8 wrap adr
  */
        movl    $COL08_ADR, %esi         /* set address to min(8) col wrap address */
        movl    $COL08_DATA, %eax        /* pattern for min (8) col wrap */
	movl    %eax, (%esi)             /* write min col pattern @ min col adr */
	movl    (%esi), %ebx             /* optional read */
        cmpl    %ebx,%eax                /* to verify write */
        jnz     bad_ram                  /* this ram is bad */
 /*
  * write row 14 wrap adr
  */