Hi Tony, Thanks for the review, On Wed, Apr 25, 2012 at 06:03:14PM +0100, Tony Lindgren wrote: (...) > > #define GPMC_ECC1_RESULT 0x200 > > +#define GPMC_ECC_BCH_RESULT_0 0x240 > > Can you please add a comment here saying something like: > > #define GPMC_ECC_BCH_RESULT_0 0x240 /* Not available on omap2 */ OK sure. > > + /* check if ecc module is in use */ > > + if (gpmc_ecc_used != -EINVAL) > > + return -EINVAL; > > + /* > > + * FIXME: some OMAP3 revisions have a hardware bug which prevents > > + * the 4-bit BCH mode from working properly. Such revisions could be > > + * detected and rejected here. > > + */ > > This should then be disabled to avoid corruption. Maybe only allow it > initially on omaps that have been tested? And for omap2 it should return > error for sure. OK I'll add a check. > > Or do you know the broken omap3 versions? Well, I was hoping that someone from linux-omap could tell me :) I found this HW ECC feature table in http://processors.wiki.ti.com/index.php/Raw_NAND_ECC: 1b 4b 8b --------------------------- OMAP35x YES NO YES AM35x YES YES YES AM/DM37x YES YES YES and other wiki pages confirmed that 4-bit mode is not supported on all OMAP35xx chips. OTOH, I know from TI support that 4-bit mode is at least supported on OMAP3630 ES1.x (x >= 1). So, a conservative approach would be to reject 4-bit mode on all chips but omap3630 with rev >= 1.1. Other revisions/chips could be added later if they are confirmed to work; what do you think ? > Also, should you first request this feature in case multiple drivers > need to share it? According to TI documentation (OMAP36xx ES1.x TRM, §10.1.4, GPMC functional diagram), the GPMC ECC engines (Hamming and BCH) are dedicated to NAND access only; therefore I believe the mtd driver is the only potential user of this feature. Also, the existing Hamming ecc API does not perform any request; or did I miss something? If I need to perform the request, is there an existing api to do so? Thanks, -- Ivan -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
