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[/] [openrisc/] [trunk/] [orpsocv2/] [sw/] [bootrom/] [bootrom.S] - Rev 361
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//////////////////////////////////////////////////////////////////////
/// ////
/// bootrom ////
/// ////
/// Assembly programs to be embedded inside system to aid boot ////
/// ////
/// Julius Baxter, julius@opencores.org ////
/// ////
//////////////////////////////////////////////////////////////////////
//// ////
//// Copyright (C) 2009, 2010 Authors and OPENCORES.ORG ////
//// ////
//// This source file may be used and distributed without ////
//// restriction provided that this copyright statement is not ////
//// removed from the file and that any derivative work contains ////
//// the original copyright notice and the associated disclaimer. ////
//// ////
//// This source file is free software; you can redistribute it ////
//// and/or modify it under the terms of the GNU Lesser General ////
//// Public License as published by the Free Software Foundation; ////
//// either version 2.1 of the License, or (at your option) any ////
//// later version. ////
//// ////
//// This source 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 Lesser General Public License for more ////
//// details. ////
//// ////
//// You should have received a copy of the GNU Lesser General ////
//// Public License along with this source; if not, download it ////
//// from http://www.opencores.org/lgpl.shtml ////
//// ////
//////////////////////////////////////////////////////////////////////
// Defines for which bootrom app to use are in board.h - TODO: use the
// processed orspoc-defines.v file for this define. It makes more sense
// as this software ends up as gates.
#include "board.h"
#ifdef BOOTLOADER_SPI_FLASH
/* Assembly program to go into the boot ROM */
/* Currently just loads a program from SPI flash into RAM */
/* Assuming address at RAM_LOAD_BASE gets clobbered, we need
a byte writable address somewhere!*/
#define SPI_BASE SPI0_BASE
/* simple_spi driver */
#define SPI_SPCR 0x0
#define SPI_SPSR 0x1
#define SPI_SPDR 0x2
#define SPI_SPER 0x3
#define SPI_SPSS 0x4
#define SPI_SPCR_XFER_GO 0x51
#define SPI_SPSS_INIT 0x1
#define SPI_SPSR_RX_CHECK 0x01 /* Check bit 0 is cleared, fifo !empty*/
#define RAM_LOAD_BASE SDRAM_BASE
#define RESET_ADDR 0x100
boot_init:
l.movhi r0, 0
l.movhi r1, RAM_LOAD_BASE
l.movhi r4, hi(SPI_BASE)
spi_init:
l.ori r2, r0, SPI_SPCR_XFER_GO /* Setup SPCR with enable bit set */
l.sb SPI_SPCR(r4), r2
l.sb SPI_SPSS(r4), r0 /* Clear SPI slave selects */
l.ori r6, r0, SPI_SPSS_INIT
l.sb SPI_SPSS(r4), r6 /* Now put in appropriate slave select */
l.jal spi_xfer
l.ori r3, r0, 0x3 /* READ command opcode for SPI device */
l.jal spi_xfer
l.or r3, r0, r0
l.jal spi_xfer
l.or r3, r0, r0
l.jal spi_xfer
l.or r3, r0, r0
l.movhi r6, 0
l.movhi r7, 0xffff
copy:
l.jal spi_xfer /* Read a byte into r3 */
l.add r8, r1, r6 /* Calculate store address */
l.sb 0(r8), r3 /* Write byte to memory */
l.addi r6, r6, 1 /* Increment counter */
l.sfeqi r6, 0x4 /* Is this the first word */
l.bf store_sizeword /* put sizeword in the register */
l.sfeq r6, r7 /* Check if we've finished loading the words */
l.bnf copy /* Continue copying if not last word */
l.nop
goto_reset:
l.ori r1, r1, RESET_ADDR
l.jr r1
l.sb SPI_SPSS(r4), r0 /* Clear SPI slave selects */
store_sizeword:
l.j copy
l.lwz r7, 0(r1) /* Size word is in first word of SDRAM */
spi_xfer:
l.sb SPI_SPDR(r4), r3 /* Dummy write what's in r3 */
l.ori r3, r0, SPI_SPSR_RX_CHECK /* r3 = , ensure loop just once */
spi_xfer_poll:
l.andi r3, r3, SPI_SPSR_RX_CHECK /* AND read fifo bit empty */
l.sfeqi r3, SPI_SPSR_RX_CHECK /* is bit set? ... */
l.bf spi_xfer_poll /* ... if so, rxfifo empty, keep polling */
l.lbz r3, SPI_SPSR(r4) /* Read SPSR */
l.jr r9
l.lbz r3, SPI_SPDR(r4) /* Get data byte */
#endif
#ifdef BOOTLOADER_GOTO_RESET
/* Jump to reset vector in the SDRAM */
l.movhi r0, 0
l.movhi r4, SDRAM_BASE
l.ori r4, r4, 0x100
l.jr r4
l.nop
#endif
#ifdef BOOTLOADER_LOOP_AT_ZERO
/* Don't load app via SPI, instead just put an infinite loop into bottom
of memory and jump there.
*/
l.movhi r0, 0
l.movhi r4, SDRAM_BASE
l.sw 0x0(r4), r0
l.movhi r5, hi(0x15000001) /* A l.nop 1 so sim exits if this enabled */
l.ori r5, r5, lo(0x15000001)
l.sw 0x4(r4), r5
l.sw 0x8(r4), r5
l.sw 0xc(r4), r5
l.jr r4
l.nop
#endif
#ifdef BOOTLOADER_LOOP_IN_ROM
/* Don't load app via SPI, instead just put an infinite loop into bottom
of memory and jump there.
*/
l.movhi r0, 0
l.nop 0x1
l.j 0
l.nop
l.nop
#endif
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