On Wednesday 10 August 2016 04:49 PM, Karl Beldan wrote: > On Wed, Aug 10, 2016 at 03:01:30PM +0530, Sekhar Nori wrote: >> On Wednesday 10 August 2016 02:34 PM, Karl Beldan wrote: >>> On Wed, Aug 10, 2016 at 02:01:57PM +0530, Sekhar Nori wrote: >>>> On Tuesday 09 August 2016 10:45 PM, Karl Beldan wrote: >>>>> This adds DT support for the NAND connected to the SoC AEMIF. >>>>> The parameters (timings, ecc) are the same as what the board ships with >>>>> (default AEMIF timings, 1bit ECC) and improvements will be handled in >>>>> due course. >>>> >>>> I disagree that we need to be compatible to the software that ships with >>>> the board. Thats software was last updated 3 years ago. Instead I would >>>> concern with what the hardware supports. So, if the hardware can support >>>> 4-bit ECC, I would use that. >>>> >>> I am not saying we _need_ to be compatible. >> >> Alright then, please drop references to what software the board ships >> with in the commit message and in the patch itself. >> > > I hadn't seen this comment before sending v2. > >>> >>>> If driver is broken for 4-bit ECC, please fix that up first. >>>> >>> Since this issue is completely separate from my DT improvements >>> I'll stick to resubmitting the series, applying my LCDK changes to the >>> EVM too, besides you'll be able to compare the behavior without ECC >>> discrepancies. >>> I took note that you are likely to not apply without the ECC fix. >> >> Yeah, I would not like to apply with 1-bit ECC now and then change to >> 4-bit ECC soon after. >> > > Both mityomapl138 from mainline and hawkboard from TI's BSP release > include the comment: > - "4 bit mode is not supported with 16 bit NAND" > It is not clear whether they imply that the HW has issues or if it's SW
At least the TRM says "The EMIFA supports 4-bit ECC on 8-bit/16-bit NAND Flash.". And then the TRM goes on to describe how 4-bit ECC is supposed to work for 16-bit NAND. I could not find any errata related to this in the errata document. > only, but 4-bits ECC is a different matter and I hope you'll integrate > the current changes prior to tackling it. Lets apply everything together. This is a new feature, not a bug fix. There is no need to rush it. Also, for the NAND part on LCDK, per the micron datasheet, minimum of 4-bit ECC is needed. I will take a look at other patches in this series. Regards, Sekhar
