init.s

uboot在arm处理器s3c2410的移植代码

/*------------------------------------------------------------------------------+ */
/* */
/*       This source code has been made available to you by IBM on an AS-IS */
/*       basis.  Anyone receiving this source is licensed under IBM */
/*       copyrights to use it in any way he or she deems fit, including */
/*       copying it, modifying it, compiling it, and redistributing it either */
/*       with or without modifications.  No license under IBM patents or */
/*       patent applications is to be implied by the copyright license. */
/* */
/*       Any user of this software should understand that IBM cannot provide */
/*       technical support for this software and will not be responsible for */
/*       any consequences resulting from the use of this software. */
/* */
/*       Any person who transfers this source code or any derivative work */
/*       must include the IBM copyright notice, this paragraph, and the */
/*       preceding two paragraphs in the transferred software. */
/* */
/*       COPYRIGHT   I B M   CORPORATION 1995 */
/*       LICENSED MATERIAL  -  PROGRAM PROPERTY OF I B M */
/*------------------------------------------------------------------------------- */

/*----------------------------------------------------------------------------- */
/* Function:     ext_bus_cntlr_init */
/* Description:  Initializes the External Bus Controller for the external */
/*		peripherals. IMPORTANT: For pass1 this code must run from */
/*		cache since you can not reliably change a peripheral banks */
/*		timing register (pbxap) while running code from that bank. */
/*		For ex., since we are running from ROM on bank 0, we can NOT */
/*		execute the code that modifies bank 0 timings from ROM, so */
/*		we run it from cache. */
/*	Bank 0 - Flash and SRAM */
/*	Bank 1 - NVRAM/RTC */
/*	Bank 2 - Keyboard/Mouse controller */
/*	Bank 3 - IR controller */
/*	Bank 4 - not used */
/*	Bank 5 - not used */
/*	Bank 6 - not used */
/*	Bank 7 - FPGA registers */
/*-----------------------------------------------------------------------------#include <config.h> */
#include <ppc4xx.h>

#define _LINUX_CONFIG_H 1	/* avoid reading Linux autoconf.h file	*/

#include <ppc_asm.tmpl>
#include <ppc_defs.h>

#include <asm/cache.h>
#include <asm/mmu.h>

/* CRAY - L1: only nominally a 'walnut', since ext.Bus.Cntlr is all empty */
/*	except for #1 which we use for DMA'ing to IOCA-like things, so the */
/*	control registers to set that up are determined by what we've */
/*	empirically discovered work there. */

	.globl	ext_bus_cntlr_init
ext_bus_cntlr_init:
	mflr    r4                      /* save link register */
	bl      ..getAddr
..getAddr:
	mflr    r3                      /* get address of ..getAddr */
	mtlr    r4                      /* restore link register */
	addi    r4,0,14                 /* set ctr to 10; used to prefetch */
	mtctr   r4                      /* 10 cache lines to fit this function */
					/* in cache (gives us 8x10=80 instrctns) */
..ebcloop:
	icbt    r0,r3                   /* prefetch cache line for addr in r3 */
	addi    r3,r3,32		/* move to next cache line */
	bdnz    ..ebcloop               /* continue for 10 cache lines */

	/*------------------------------------------------------------------- */
	/* Delay to ensure all accesses to ROM are complete before changing */
	    /* bank 0 timings. 200usec should be enough. */
	/*   200,000,000 (cycles/sec) X .000200 (sec) = 0x9C40 cycles */
	/*------------------------------------------------------------------- */
	addis	r3,0,0x0
	ori     r3,r3,0xA000          /* ensure 200usec have passed since reset */
	mtctr   r3
..spinlp:
	bdnz    ..spinlp                /* spin loop */


	/*---------------------------------------------------------------------- */
	/* Peripheral Bank 0 (Flash) initialization */
	/*---------------------------------------------------------------------- */
		/* 0x7F8FFE80 slowest boot */
	addi    r4,0,pb0ap
	mtdcr   ebccfga,r4
	addis   r4,0,0x9B01
	ori     r4,r4,0x5480
	mtdcr   ebccfgd,r4

	addi    r4,0,pb0cr
	mtdcr   ebccfga,r4
	addis   r4,0,0xFFC5           /* BAS=0xFFC,BS=0x4(4MB),BU=0x3(R/W), */
	ori     r4,r4,0x8000          /* BW=0x0( 8 bits) */
	mtdcr   ebccfgd,r4

	blr

	/*---------------------------------------------------------------------- */
	/* Peripheral Bank 1 (NVRAM/RTC) initialization */
		/* CRAY:the L1 has NOT this bank, it is tied to SV2/IOCA/etc/ instead */
		/* and we do DMA on it.  The ConfigurationRegister part is threfore */
		/* almost arbitrary, except that our linux driver needs to know the */
		/* address, but it can query, it.. */
		/* */
		/* The AccessParameter is CRITICAL, */
		/* thouch, since it needs to agree with the electrical timings on the */
		/* IOCA parallel interface.  That value is: 0x0185,4380 */
		/* BurstModeEnable			BME=0 */
		/* TransferWait				TWT=3 */
		/* ChipSelectOnTiming		CSN=1 */
		/* OutputEnableOnTimimg		OEN=1 */
		/* WriteByteEnableOnTiming	WBN=1 */
		/* WriteByteEnableOffTiming	WBF=0 */
		/* TransferHold				TH=1 */
		/* ReadyEnable				RE=1 */
		/* SampleOnReady			SOR=1 */
		/* ByteEnableMode			BEM=0 */
		/* ParityEnable				PEN=0 */
		/* all reserved bits=0 */
	/*---------------------------------------------------------------------- */
	/*---------------------------------------------------------------------- */
	addi    r4,0,pb1ap
	mtdcr   ebccfga,r4
	addis   r4,0,0x0185		/* hiword */
	ori     r4,r4,0x4380	/* loword */
	mtdcr   ebccfgd,r4

	addi    r4,0,pb1cr
	mtdcr   ebccfga,r4
	addis   r4,0,0xF001           /* BAS=0xF00,BS=0x0(1MB),BU=0x3(R/W), */
	ori     r4,r4,0x8000          /* BW=0x0( 8 bits) */
	mtdcr   ebccfgd,r4

	blr

/*----------------------------------------------------------------------------- */
/* Function:	sdram_init */
/* Description:	Configures SDRAM memory banks. */
/*				NOTE: for CrayL1 we have ECC memory, so enable it. */
/*....now done in C in L1.c:init_sdram for readability. */
/*----------------------------------------------------------------------------- */
	.globl  sdram_init

sdram_init:
 blr