York, ok - will give it a try tomorrow. Cheers, André
York Sun yorksun@freescale.com hat am 6. April 2011 um 18:37 geschrieben:
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:
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.
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
--
Gruß, André Schwarz
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