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) 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..? 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.] Nick. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
