Nick Thompson wrote: > On 01/12/09 10:13, Nick Thompson wrote: >> On 01/12/09 00:55, Scott Wood wrote: > >>> This change will break drivers that support large page and use the >>> default read_page functions, but do not implement cmd_ctrl (they replace >>> cmdfunc instead). This includes fsl_elbc_nand, mxc_nand, and >>> mpc5121_nfc. While I'd like to move them to implementing their own >>> read_page-type functions instead of cmdfunc, is there any way to make it >>> a smoother transition? >> Yes, as it stands they would need modifying simultaneously and I have no >> way to test such a change myself. The only required change in cmdfunc is >> not to wait after a read0 request. You maybe in a better position to decide >> if this has wider repercussions, but I will take a look at the above >> drivers as well. [This is the main reason I made this an RFC]. > > How about, if nand_wait_cache_load was replaceable (by a no-op in your case)
Or it could be off by default, and enabled only on those platforms where it works and is beneficial. > and the pre-fetch optimisation could be disabled by setting rstate to > (INIT | NO_REQ) on every page read function call #ifdef > CONFIG_NAND_NO_PREFETCH_READS? > > This leaves a problem with NAND_CMD_RNDOUT which is used by oob_first > page reads but not supported by fsl_elbc_cmdfunc. I expect you don't use > oob_first though..? Right. It's also used on swecc, but we don't use that either. > I believe this would allow you to restore the original sequences and keep you > going until you can define your own page read functions. > > [BTW these changes applied quite cleanly to my Linux tree and give similar > performance gains there as well. If we can reach agreement here, I will > make patches for Linux as well. Unfortunately, my tree is 2.6.18 with > backported NAND support from 2.6.32rc1, but I can deal with that.] If possible, it would be nice to run these patches by the Linux list now, so we get their feedback earlier rather than later. -Scott _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
