path: root/board/mpc8266ads/mpc8266ads.c

/*
 * (C) Copyright 2001
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * Modified during 2001 by
 * Advanced Communications Technologies (Australia) Pty. Ltd.
 * Howard Walker, Tuong Vu-Dinh
 *
 * (C) Copyright 2001, Stuart Hughes, Lineo Inc, stuarth@lineo.com
 * Added support for the 16M dram simm on the 8260ads boards
 *
 * 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
 */

#include <common.h>
#include <ioports.h>
#include <i2c.h>
#include <mpc8260.h>
#include <pci.h>

/*
 * PBI Page Based Interleaving
 *   PSDMR_PBI page based interleaving
 *   0         bank based interleaving
 * External Address Multiplexing (EAMUX) adds a clock to address cycles
 *   (this can help with marginal board layouts)
 *   PSDMR_EAMUX  adds a clock
 *   0            no extra clock
 * Buffer Command (BUFCMD) adds a clock to command cycles.
 *   PSDMR_BUFCMD adds a clock
 *   0            no extra clock
 */
#define CONFIG_PBI		0
#define PESSIMISTIC_SDRAM	0
#define EAMUX			0	/* EST requires EAMUX */
#define BUFCMD			0


/*
 * I/O Port configuration table
 *
 * if conf is 1, then that port pin will be configured at boot time
 * according to the five values podr/pdir/ppar/psor/pdat for that entry
 */

const iop_conf_t iop_conf_tab[4][32] = {

    /* Port A configuration */
    {	/*	      conf ppar psor pdir podr pdat */
        /* PA31 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 TxENB */
	/* PA30 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 TxClav   */
	/* PA29 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 TxSOC  */
	/* PA28 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 RxENB */
	/* PA27 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 RxSOC */
	/* PA26 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 RxClav */
	/* PA25 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[0] */
	/* PA24 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[1] */
	/* PA23 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[2] */
	/* PA22 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[3] */
	/* PA21 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[4] */
	/* PA20 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[5] */
	/* PA19 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[6] */
	/* PA18 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXD[7] */
	/* PA17 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[7] */
	/* PA16 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[6] */
	/* PA15 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[5] */
	/* PA14 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[4] */
	/* PA13 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[3] */
	/* PA12 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[2] */
	/* PA11 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[1] */
	/* PA10 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXD[0] */
	/* PA9  */ {   0,   1,   1,   1,   0,   0   }, /* FCC1 L1TXD */
	/* PA8  */ {   0,   1,   1,   0,   0,   0   }, /* FCC1 L1RXD */
	/* PA7  */ {   0,   0,   0,   1,   0,   0   }, /* PA7 */
	/* PA6  */ {   1,   1,   1,   1,   0,   0   }, /* TDM A1 L1RSYNC */
	/* PA5  */ {   0,   0,   0,   1,   0,   0   }, /* PA5 */
	/* PA4  */ {   0,   0,   0,   1,   0,   0   }, /* PA4 */
	/* PA3  */ {   0,   0,   0,   1,   0,   0   }, /* PA3 */
	/* PA2  */ {   0,   0,   0,   1,   0,   0   }, /* PA2 */
	/* PA1  */ {   1,   0,   0,   0,   0,   0   }, /* FREERUN */
	/* PA0  */ {   0,   0,   0,   1,   0,   0   }  /* PA0 */
    },

    /* Port B configuration */
    {   /*	      conf ppar psor pdir podr pdat */
	/* PB31 */ {   1,   1,   0,   1,   0,   0   }, /* FCC2 MII TX_ER */
	/* PB30 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RX_DV */
	/* PB29 */ {   1,   1,   1,   1,   0,   0   }, /* FCC2 MII TX_EN */
	/* PB28 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RX_ER */
	/* PB27 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII COL */
	/* PB26 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII CRS */
	/* PB25 */ {   1,   1,   0,   1,   0,   0   }, /* FCC2 MII TxD[3] */
	/* PB24 */ {   1,   1,   0,   1,   0,   0   }, /* FCC2 MII TxD[2] */
	/* PB23 */ {   1,   1,   0,   1,   0,   0   }, /* FCC2 MII TxD[1] */
	/* PB22 */ {   1,   1,   0,   1,   0,   0   }, /* FCC2 MII TxD[0] */
	/* PB21 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RxD[0] */
	/* PB20 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RxD[1] */
	/* PB19 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RxD[2] */
	/* PB18 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RxD[3] */
	/* PB17 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RX_DIV */
	/* PB16 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RX_ERR */
	/* PB15 */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TX_ERR */
	/* PB14 */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TX_EN */
	/* PB13 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:COL */
	/* PB12 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:CRS */
	/* PB11 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RXD */
	/* PB10 */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RXD */
	/* PB9  */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RXD */
	/* PB8  */ {   0,   1,   0,   0,   0,   0   }, /* FCC3:RXD */
	/* PB7  */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TXD */
	/* PB6  */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TXD */
	/* PB5  */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TXD */
	/* PB4  */ {   0,   1,   0,   1,   0,   0   }, /* FCC3:TXD */
	/* PB3  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PB2  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PB1  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PB0  */ {   0,   0,   0,   0,   0,   0   }  /* pin doesn't exist */
    },

    /* Port C */
    {   /*	      conf ppar psor pdir podr pdat */
	/* PC31 */ {   0,   0,   0,   1,   0,   0   }, /* PC31 */
	/* PC30 */ {   0,   0,   0,   1,   0,   0   }, /* PC30 */
	/* PC29 */ {   0,   1,   1,   0,   0,   0   }, /* SCC1 EN *CLSN */
	/* PC28 */ {   0,   0,   0,   1,   0,   0   }, /* PC28 */
	/* PC27 */ {   0,   0,   0,   1,   0,   0   }, /* UART Clock in */
	/* PC26 */ {   0,   0,   0,   1,   0,   0   }, /* PC26 */
	/* PC25 */ {   0,   0,   0,   1,   0,   0   }, /* PC25 */
	/* PC24 */ {   0,   0,   0,   1,   0,   0   }, /* PC24 */
	/* PC23 */ {   0,   1,   0,   1,   0,   0   }, /* ATMTFCLK */
	/* PC22 */ {   0,   1,   0,   0,   0,   0   }, /* ATMRFCLK */
	/* PC21 */ {   0,   1,   0,   0,   0,   0   }, /* SCC1 EN RXCLK */
	/* PC20 */ {   0,   1,   0,   0,   0,   0   }, /* SCC1 EN TXCLK */
	/* PC19 */ {   1,   1,   0,   0,   0,   0   }, /* FCC2 MII RX_CLK CLK13 */
	/* PC18 */ {   1,   1,   0,   0,   0,   0   }, /* FCC Tx Clock (CLK14) */
	/* PC17 */ {   0,   0,   0,   1,   0,   0   }, /* PC17 */
	/* PC16 */ {   0,   1,   0,   0,   0,   0   }, /* FCC Tx Clock (CLK16) */
	/* PC15 */ {   0,   0,   0,   1,   0,   0   }, /* PC15 */
	/* PC14 */ {   0,   1,   0,   0,   0,   0   }, /* SCC1 EN *CD */
	/* PC13 */ {   0,   0,   0,   1,   0,   0   }, /* PC13 */
	/* PC12 */ {   0,   1,   0,   1,   0,   0   }, /* PC12 */
	/* PC11 */ {   0,   0,   0,   1,   0,   0   }, /* LXT971 transmit control */
	/* PC10 */ {   1,   0,   0,   1,   0,   0   }, /* LXT970 FETHMDC */
	/* PC9  */ {   1,   0,   0,   0,   0,   0   }, /* LXT970 FETHMDIO */
	/* PC8  */ {   0,   0,   0,   1,   0,   0   }, /* PC8 */
	/* PC7  */ {   0,   0,   0,   1,   0,   0   }, /* PC7 */
	/* PC6  */ {   0,   0,   0,   1,   0,   0   }, /* PC6 */
	/* PC5  */ {   0,   0,   0,   1,   0,   0   }, /* PC5 */
	/* PC4  */ {   0,   0,   0,   1,   0,   0   }, /* PC4 */
	/* PC3  */ {   0,   0,   0,   1,   0,   0   }, /* PC3 */
	/* PC2  */ {   0,   0,   0,   1,   0,   1   }, /* ENET FDE */
	/* PC1  */ {   0,   0,   0,   1,   0,   0   }, /* ENET DSQE */
	/* PC0  */ {   0,   0,   0,   1,   0,   0   }, /* ENET LBK */
    },

    /* Port D */
    {   /*	      conf ppar psor pdir podr pdat */
	/* PD31 */ {   1,   1,   0,   0,   0,   0   }, /* SCC1 EN RxD */
	/* PD30 */ {   1,   1,   1,   1,   0,   0   }, /* SCC1 EN TxD */
	/* PD29 */ {   0,   1,   0,   1,   0,   0   }, /* SCC1 EN TENA */
	/* PD28 */ {   0,   1,   0,   0,   0,   0   }, /* PD28 */
	/* PD27 */ {   0,   1,   1,   1,   0,   0   }, /* PD27 */
	/* PD26 */ {   0,   0,   0,   1,   0,   0   }, /* PD26 */
	/* PD25 */ {   0,   0,   0,   1,   0,   0   }, /* PD25 */
	/* PD24 */ {   0,   0,   0,   1,   0,   0   }, /* PD24 */
	/* PD23 */ {   0,   0,   0,   1,   0,   0   }, /* PD23 */
	/* PD22 */ {   0,   0,   0,   1,   0,   0   }, /* PD22 */
	/* PD21 */ {   0,   0,   0,   1,   0,   0   }, /* PD21 */
	/* PD20 */ {   0,   0,   0,   1,   0,   0   }, /* PD20 */
	/* PD19 */ {   0,   0,   0,   1,   0,   0   }, /* PD19 */
	/* PD18 */ {   0,   0,   0,   1,   0,   0   }, /* PD18 */
	/* PD17 */ {   0,   1,   0,   0,   0,   0   }, /* FCC1 ATMRXPRTY */
	/* PD16 */ {   0,   1,   0,   1,   0,   0   }, /* FCC1 ATMTXPRTY */
	/* PD15 */ {   1,   1,   1,   0,   1,   0   }, /* I2C SDA */
	/* PD14 */ {   1,   1,   1,   0,   1,   0   }, /* I2C SCL */
	/* PD13 */ {   0,   0,   0,   0,   0,   0   }, /* PD13 */
	/* PD12 */ {   0,   0,   0,   0,   0,   0   }, /* PD12 */
	/* PD11 */ {   0,   0,   0,   0,   0,   0   }, /* PD11 */
	/* PD10 */ {   0,   0,   0,   0,   0,   0   }, /* PD10 */
	/* PD9  */ {   1,   1,   0,   1,   0,   0   }, /* SMC1 TXD */
	/* PD8  */ {   1,   1,   0,   0,   0,   0   }, /* SMC1 RXD */
	/* PD7  */ {   0,   0,   0,   1,   0,   1   }, /* PD7 */
	/* PD6  */ {   0,   0,   0,   1,   0,   1   }, /* PD6 */
	/* PD5  */ {   0,   0,   0,   1,   0,   1   }, /* PD5 */
	/* PD4  */ {   0,   0,   0,   1,   0,   1   }, /* PD4 */
	/* PD3  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PD2  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PD1  */ {   0,   0,   0,   0,   0,   0   }, /* pin doesn't exist */
	/* PD0  */ {   0,   0,   0,   0,   0,   0   }  /* pin doesn't exist */
    }
};

typedef struct bscr_ {
	unsigned long bcsr0;
	unsigned long bcsr1;
	unsigned long bcsr2;
	unsigned long bcsr3;
	unsigned long bcsr4;
	unsigned long bcsr5;
	unsigned long bcsr6;
	unsigned long bcsr7;
} bcsr_t;

typedef struct pci_ic_s {
	unsigned long pci_int_stat;
	unsigned long pci_int_mask;
} pci_ic_t;

void reset_phy(void)
{
    volatile bcsr_t  *bcsr           = (bcsr_t *)CFG_BCSR;

    /* reset the FEC port */
    bcsr->bcsr1                    &= ~FETH_RST;
    bcsr->bcsr1                    |= FETH_RST;
}


int board_pre_init (void)
{
    volatile bcsr_t  *bcsr         = (bcsr_t *)CFG_BCSR;
    volatile pci_ic_t *pci_ic      = (pci_ic_t *) CFG_PCI_INT;

    bcsr->bcsr1                    = ~FETHIEN & ~RS232EN_1 & ~RS232EN_2;

    /* mask all PCI interrupts */
    pci_ic->pci_int_mask |= 0xfff00000;
    
    return 0;
}

int checkboard(void)
{
    puts ("Board: Motorola MPC8266ADS\n");
    return 0;
}

long int initdram(int board_type)
{
	/* Autoinit part stolen from board/sacsng/sacsng.c */
    volatile immap_t *immap         = (immap_t *)CFG_IMMR;
    volatile memctl8260_t *memctl   = &immap->im_memctl;
    volatile uchar c = 0xff;
    volatile uchar *ramaddr = (uchar *)(CFG_SDRAM_BASE + 0x8);
    uint  psdmr = CFG_PSDMR;
    int i;

    uint   psrt = 0x21;					/* for no SPD */
    uint   chipselects = 1;				/* for no SPD */
    uint   sdram_size = CFG_SDRAM_SIZE * 1024 * 1024;	/* for no SPD */
    uint   or = CFG_OR2_PRELIM;				/* for no SPD */
    uint   data_width;
    uint   rows;
    uint   banks;
    uint   cols;
    uint   caslatency;
    uint   width;
    uint   rowst;
    uint   sdam;
    uint   bsma;
    uint   sda10;
    u_char spd_size;
    u_char data;
    u_char cksum;
    int    j;

    /* Keep the compiler from complaining about potentially uninitialized vars */
    data_width = rows = banks = cols = caslatency = 0;

    /*
     * Read the SDRAM SPD EEPROM via I2C.
     */
	i2c_init (CFG_I2C_SPEED, CFG_I2C_SLAVE);

    i2c_read(SDRAM_SPD_ADDR, 0, 1, &data, 1);
    spd_size = data;
    cksum    = data;
    for(j = 1; j < 64; j++) 
	{	/* read only the checksummed bytes */
	/* note: the I2C address autoincrements when alen == 0 */
		i2c_read(SDRAM_SPD_ADDR, 0, 0, &data, 1);
		/*printf("addr %d = 0x%02x\n", j, data);*/
		if(j ==  5) chipselects = data & 0x0F;
		else if(j ==  6) data_width  = data;
		else if(j ==  7) data_width |= data << 8;
		else if(j ==  3) rows        = data & 0x0F;
		else if(j ==  4) cols        = data & 0x0F;
		else if(j == 12) 
		{
			/*
				 * Refresh rate: this assumes the prescaler is set to
			 * approximately 0.39uSec per tick and the target refresh period 
			 * is about 85% of maximum.
			 */
			switch(data & 0x7F) 
			{
					default:
					case 0:  psrt = 0x21; /*  15.625uS */  break;
					case 1:  psrt = 0x07; /*   3.9uS   */  break;
					case 2:  psrt = 0x0F; /*   7.8uS   */  break;
					case 3:  psrt = 0x43; /*  31.3uS   */  break;
					case 4:  psrt = 0x87; /*  62.5uS   */  break;
					case 5:  psrt = 0xFF; /* 125uS     */  break;
			}
		}
		else if(j == 17) banks       = data;
		else if(j == 18) 
		{
			caslatency = 3; /* default CL */
#		    if(PESSIMISTIC_SDRAM)
				if((data & 0x04) != 0) caslatency = 3;
				else if((data & 0x02) != 0) caslatency = 2;
				else if((data & 0x01) != 0) caslatency = 1;
#			else
				if((data & 0x01) != 0) caslatency = 1;
				else if((data & 0x02) != 0) caslatency = 2;
				else if((data & 0x04) != 0) caslatency = 3;
#			endif
			else 
			{
			printf ("WARNING: Unknown CAS latency 0x%02X, using 3\n",
					data);
			}
		}
		else if(j == 63) 
		{
			if(data != cksum) 
			{
				printf ("WARNING: Configuration data checksum failure:"
					" is 0x%02x, calculated 0x%02x\n",
				data, cksum);
			}
		}
		cksum += data;
    }

    /* We don't trust CL less than 2 (only saw it on an old 16MByte DIMM) */
    if(caslatency < 2) {
		printf("CL was %d, forcing to 2\n", caslatency);
		caslatency = 2;
    }
    if(rows > 14) {
		printf("This doesn't look good, rows = %d, should be <= 14\n", rows);
		rows = 14;
    }
    if(cols > 11) {
		printf("This doesn't look good, columns = %d, should be <= 11\n", cols);
		cols = 11;
    }

    if((data_width != 64) && (data_width != 72))
    {
		printf("WARNING: SDRAM width unsupported, is %d, expected 64 or 72.\n",
			data_width);
    }
    width = 3;		/* 2^3 = 8 bytes = 64 bits wide */
    /*
     * Convert banks into log2(banks)
     */
    if     (banks == 2)	banks = 1;
    else if(banks == 4)	banks = 2;
    else if(banks == 8)	banks = 3;


    sdram_size = 1 << (rows + cols + banks + width);

#if(CONFIG_PBI == 0)	/* bank-based interleaving */
    rowst = ((32 - 6) - (rows + cols + width)) * 2;
#else
    rowst = 32 - (rows + banks + cols + width);
#endif

   or = ~(sdram_size - 1)    |	/* SDAM address mask	*/
	  ((banks-1) << 13)   |	/* banks per device	*/
	  (rowst << 9)        |	/* rowst		*/
	  ((rows - 9) << 6);	/* numr			*/


    /*printf("memctl->memc_or2 = 0x%08x\n", or);*/

    /*
     * SDAM specifies the number of columns that are multiplexed
     * (reference AN2165/D), defined to be (columns - 6) for page
     * interleave, (columns - 8) for bank interleave.
     *
     * BSMA is 14 - max(rows, cols).  The bank select lines come
     * into play above the highest "address" line going into the
     * the SDRAM.
     */
#if(CONFIG_PBI == 0)	/* bank-based interleaving */
    sdam = cols - 8;
    bsma = ((31 - width) - 14) - ((rows > cols) ? rows : cols);
    sda10 = sdam + 2;
#else
    sdam = cols - 6;
    bsma = ((31 - width) - 14) - ((rows > cols) ? rows : cols);
    sda10 = sdam;
#endif
#if(PESSIMISTIC_SDRAM)
    psdmr = (CONFIG_PBI              |\
	     PSDMR_RFEN              |\
	     PSDMR_RFRC_16_CLK       |\
	     PSDMR_PRETOACT_8W       |\
	     PSDMR_ACTTORW_8W        |\
	     PSDMR_WRC_4C            |\
	     PSDMR_EAMUX             |\
             PSDMR_BUFCMD)           |\
	     caslatency              |\
	     ((caslatency - 1) << 6) |	/* LDOTOPRE is CL - 1 */ \
	     (sdam << 24)            |\
	     (bsma << 21)            |\
	     (sda10 << 18);
#else
    psdmr = (CONFIG_PBI              |\
	     PSDMR_RFEN              |\
	     PSDMR_RFRC_7_CLK        |\
	     PSDMR_PRETOACT_3W       |	/* 1 for 7E parts (fast PC-133) */ \
	     PSDMR_ACTTORW_2W        |	/* 1 for 7E parts (fast PC-133) */ \
	     PSDMR_WRC_1C            |	/* 1 clock + 7nSec */
	     EAMUX                   |\
             BUFCMD)                 |\
	     caslatency              |\
	     ((caslatency - 1) << 6) |	/* LDOTOPRE is CL - 1 */ \
	     (sdam << 24)            |\
	     (bsma << 21)            |\
	     (sda10 << 18);
#endif
	/*printf("psdmr = 0x%08x\n", psdmr);*/

    /*
     * Quote from 8260 UM (10.4.2 SDRAM Power-On Initialization, 10-35):
     *
     * "At system reset, initialization software must set up the
     *  programmable parameters in the memory controller banks registers
     *  (ORx, BRx, P/LSDMR). After all memory parameters are configured,
     *  system software should execute the following initialization sequence
     *  for each SDRAM device.
     *
     *  1. Issue a PRECHARGE-ALL-BANKS command
     *  2. Issue eight CBR REFRESH commands
     *  3. Issue a MODE-SET command to initialize the mode register
     *
     * Quote from Micron MT48LC8M16A2 data sheet:
     *
     *  "...the SDRAM requires a 100uS delay prior to issuing any
     *  command other than a COMMAND INHIBIT or NOP.  Starting at some
     *  point during this 100uS period and continuing at least through
     *  the end of this period, COMMAND INHIBIT or NOP commands should
     *  be applied."
     *
     *  "Once the 100uS delay has been satisfied with at least one COMMAND
     *  INHIBIT or NOP command having been applied, a /PRECHARGE command/
     *  should be applied.  All banks must then be precharged, thereby
     *  placing the device in the all banks idle state."
     *
     *  "Once in the idle state, /two/ AUTO REFRESH cycles must be
     *  performed.  After the AUTO REFRESH cycles are complete, the
     *  SDRAM is ready for mode register programming."
     *
     *  (/emphasis/ mine, gvb)
     *
     *  The way I interpret this, Micron start up sequence is:
     *  1. Issue a PRECHARGE-BANK command (initial precharge)
     *  2. Issue a PRECHARGE-ALL-BANKS command ("all banks ... precharged")
     *  3. Issue two (presumably, doing eight is OK) CBR REFRESH commands
     *  4. Issue a MODE-SET command to initialize the mode register
     *
     *  --------
     *
     *  The initial commands are executed by setting P/LSDMR[OP] and
     *  accessing the SDRAM with a single-byte transaction."
     *
     * The appropriate BRx/ORx registers have already been set when we
     * get here. The SDRAM can be accessed at the address CFG_SDRAM_BASE.
     */

    memctl->memc_mptpr = CFG_MPTPR;
    memctl->memc_psrt  = psrt;

    memctl->memc_br2 = CFG_BR2_PRELIM;
    memctl->memc_or2 = or;
    
    memctl->memc_psdmr = psdmr | PSDMR_OP_PREA;
    *ramaddr = c;

    memctl->memc_psdmr = psdmr | PSDMR_OP_CBRR;
    for (i = 0; i < 8; i++)
	*ramaddr = c;

    memctl->memc_psdmr = psdmr | PSDMR_OP_MRW;
    *ramaddr = c;

    memctl->memc_psdmr = psdmr | PSDMR_OP_NORM | PSDMR_RFEN;
    *ramaddr = c;

    /*
     * Do it a second time for the second set of chips if the DIMM has
     * two chip selects (double sided).
     */
    if(chipselects > 1) 
	{
        ramaddr += sdram_size;

		memctl->memc_br3 = CFG_BR3_PRELIM + sdram_size;
		memctl->memc_or3 = or;

		memctl->memc_psdmr = psdmr | PSDMR_OP_PREA;
		*ramaddr = c;

		memctl->memc_psdmr = psdmr | PSDMR_OP_CBRR;
		for (i = 0; i < 8; i++)
			*ramaddr = c;

		memctl->memc_psdmr = psdmr | PSDMR_OP_MRW;
		*ramaddr = c;

		memctl->memc_psdmr = psdmr | PSDMR_OP_NORM | PSDMR_RFEN;
		*ramaddr = c;
    }

	/* print info */
	printf("SDRAM configuration read from SPD\n");
	printf("\tSize per side = %dMB\n", sdram_size >> 20);
	printf("\tOrganization: %d sides, %d banks, %d Columns, %d Rows, Data width = %d bits\n", chipselects, 1<<(banks), cols, rows, data_width);
	printf("\tRefresh rate = %d, CAS latency = %d\n", psrt, caslatency);
	printf("\tTotal size: ");

    return (sdram_size * chipselects);
	/*return (16 * 1024 * 1024);*/
}


#ifdef	CONFIG_PCI
struct pci_controller hose;

extern void pci_mpc8250_init(struct pci_controller *);

void pci_init_board(void)
{
	pci_mpc8250_init(&hose);
}
#endif