source: SVN/rincon/u-boot/board/freescale/mpc8544ds/ddr.c @ 55

/*
 * Copyright 2008 Freescale Semiconductor, Inc.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * Version 2 as published by the Free Software Foundation.
 */

#include <common.h>
#include <i2c.h>

#include <asm/fsl_ddr_sdram.h>

static void
get_spd(ddr2_spd_eeprom_t *spd, unsigned char i2c_address)
{
        i2c_read(i2c_address, 0, 1, (uchar *)spd, sizeof(ddr2_spd_eeprom_t));
}

unsigned int fsl_ddr_get_mem_data_rate(void)
{
        return get_ddr_freq(0);
}

void fsl_ddr_get_spd(ddr2_spd_eeprom_t *ctrl_dimms_spd,
                      unsigned int ctrl_num)
{
        unsigned int i;

        if (ctrl_num) {
                printf("%s unexpected ctrl_num = %u\n", __FUNCTION__, ctrl_num);
                return;
        }

        for (i = 0; i < CONFIG_DIMM_SLOTS_PER_CTLR; i++) {
                get_spd(&(ctrl_dimms_spd[i]), SPD_EEPROM_ADDRESS);
        }
}

void fsl_ddr_board_options(memctl_options_t *popts, unsigned int ctrl_num)
{
        /*
         * Factors to consider for clock adjust:
         *      - number of chips on bus
         *      - position of slot
         *      - DDR1 vs. DDR2?
         *      - ???
         *
         * This needs to be determined on a board-by-board basis.
         *      0110    3/4 cycle late
         *      0111    7/8 cycle late
         */
        popts->clk_adjust = 7;

        /*
         * Factors to consider for CPO:
         *      - frequency
         *      - ddr1 vs. ddr2
         */
        popts->cpo_override = 10;

        /*
         * Factors to consider for write data delay:
         *      - number of DIMMs
         *
         * 1 = 1/4 clock delay
         * 2 = 1/2 clock delay
         * 3 = 3/4 clock delay
         * 4 = 1   clock delay
         * 5 = 5/4 clock delay
         * 6 = 3/2 clock delay
         */
        popts->write_data_delay = 3;

        /*
         * Factors to consider for half-strength driver enable:
         *      - number of DIMMs installed
         */
        popts->half_strength_driver_enable = 0;
}