board/freescale/mpc8544ds/ddr.c

   1 /*
   2  * Copyright 2008 Freescale Semiconductor, Inc.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * Version 2 as published by the Free Software Foundation.
   7  */
   8
   9 #include <common.h>
  10
  11 #include <asm/fsl_ddr_sdram.h>
  12 #include <asm/fsl_ddr_dimm_params.h>
  13
  14 void fsl_ddr_board_options(memctl_options_t *popts,
  15                                 dimm_params_t *pdimm,
  16                                 unsigned int ctrl_num)
  17 {
  18         /*
  19          * Factors to consider for clock adjust:
  20          *      - number of chips on bus
  21          *      - position of slot
  22          *      - DDR1 vs. DDR2?
  23          *      - ???
  24          *
  25          * This needs to be determined on a board-by-board basis.
  26          *      0110    3/4 cycle late
  27          *      0111    7/8 cycle late
  28          */
  29         popts->clk_adjust = 7;
  30
  31         /*
  32          * Factors to consider for CPO:
  33          *      - frequency
  34          *      - ddr1 vs. ddr2
  35          */
  36         popts->cpo_override = 10;
  37
  38         /*
  39          * Factors to consider for write data delay:
  40          *      - number of DIMMs
  41          *
  42          * 1 = 1/4 clock delay
  43          * 2 = 1/2 clock delay
  44          * 3 = 3/4 clock delay
  45          * 4 = 1   clock delay
  46          * 5 = 5/4 clock delay
  47          * 6 = 3/2 clock delay
  48          */
  49         popts->write_data_delay = 3;
  50
  51         /* 2T timing enable */
  52         popts->twot_en = 1;
  53
  54         /*
  55          * Factors to consider for half-strength driver enable:
  56          *      - number of DIMMs installed
  57          */
  58         popts->half_strength_driver_enable = 0;
  59 }