On Wed, 2011-04-06 at 10:18 +0200, Andre Schwarz wrote: > Kim, York, > > >> I have made some mods to spd_sdram.c for various reason: > >> > >> 1. > >> use SPD setup also for soldered RAM. > >> This allows DDR mounting options without U-Boot change because SPD data > >> is written during in-circuit/boundary-scan testing. > > not sure I understand this - board with soldered RAM can't physically > > get the SPD data from RAM, yet SPD data were somehow acquired and > > written into some ROM, so spd_sdram() is still needed to parse& > > program the controller without requiring a new u-boot binary? > SPD data is nothing more than an I2C-EEPROM soldered on each memory module > containing the physical details of the memory devices. > Since I already have an I2C-EEPROM on the board I can use it for SPD > data, i.e. > the board's memory is configured using normal detection routines. > > During production (exactly: board testing) the EEPROM will be programmed > with an SPD > table matching the soldered memory devices. This gives some flexibility > regarding size and > speed grades ... some devices have pretty short life-cycles.
That's right. If you have the SPD in I2C-EEPROM, you have a real SPD as far as software concerns. Just provide the I2C address. > >> 3. > >> for optimized signal integrity and power consumption we need more > >> influence on > >> the on-die termination. Although the assumed default values are working > >> they > >> are far from ideal. > > board specific things like this are perfectly acceptable, of course. > ok. > > however, it should not be being done by glittering old-83xx/spd_sdram > > with an extra #ifdef for every new parameter > > ok - what about this : > > #if !defined(CONFIG_SYS_DDR_MODE_ODT_VALUE) > #define CONFIG_SYS_DDR_MODE_ODT_VALUE 0x40 > #endif > > mode_odt_enable = CONFIG_SYS_DDR_MODE_ODT_VALUE; > > > I really can't think of this change being a problem for anybody. > I would suggest to put it in fsl_ddr_board_options() in ddr.c under the board directory. There you can override any options, including popts->cs_local_opts[i].odt_rd_cfg popts->cs_local_opts[i].odt_wr_cfg popts->cpo_override York _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot