Hi Dirk, On Jan 23, 2012 12:30 AM, "Dirk Behme" <dirk.be...@de.bosch.com> wrote: > > On 23.01.2012 08:31, Simon Glass wrote: >> >> Hi, >> >> On Thu, Jan 19, 2012 at 12:56 AM, Dirk Behme <dirk.be...@de.bosch.com> wrote: >>> >>> From: Eric Miao <eric.m...@linaro.org> >>> >>> Ignore the return value of eth_getenv_enetaddr_by_index(), and if it >>> fails, fall back to use dev->enetaddr, which could be filled up by >>> the ethernet device driver: >>> >>> With the current code, introduced with below commit, eth_write_hwaddr() >>> will fail immediately if there is no eth<n>addr in the environment variables. >>> >>> However, e.g. for an overo based product that uses the SMSC911x ethernet >>> chip (with the MAC address set via EEPROM connected to the SMSC911x chip), >>> the MAC address is still OK. >>> >>> On mx28 boards that are depending on the OCOTP bits to set the MAC address >>> (like the Denx m28 board), the OCOTP bits should be used instead of >>> failing on the environment variables. >>> >>> Actually, this was the original behavior, and was later changed by >>> commit 7616e7850804c7c69e0a22c179dfcba9e8f3f587. >>> >>> Signed-off-by: Eric Miao <eric.m...@linaro.org> >>> Acked-by: Simon Glass <s...@chromium.org> >>> Acked-by: Dirk Behme <dirk.be...@de.bosch.com> >>> CC: Stefan Roese <s...@denx.de> >>> CC: Eric Miao <eric.m...@linaro.org> >>> CC: Wolfgang Denk <w...@denx.de> >>> CC: Philip Balister <phi...@balister.org> >>> CC: Zach Sadecki <z...@itwatchdogs.com> >>> --- >>> v2: Correct the referenced commit ID and update the commit message. >>> No functional change at the code itself. >>> >>> Note: This resend is based on my understanding from >>> >>> http://lists.denx.de/pipermail/u-boot/2012-January/116118.html >>> >>> Please let Eric and me know if I missed anything there. >> >> >> I don't think you have missed anything and I have already acked this. >> But I want to start a related discussion. >> >> The code structure does bug me a bit - I think it is too confusing. >> eth_getenv_enetaddr() returns an error if there is no environment >> variable set or if the address it gets from the environment variable >> is invalid. We should probably not conflate those two. The first is ok >> here, but the second isn't, I think. >> >> What if the driver has no write_hwaddr method? Do we silently ignore >> the environment variable value? >> >> Why use memcmp() against env_enetaddr when the function we just called >> returns an error that tells us whether it is supposed to be valid (the >> error return your patch squashes)? >> >> We set the hwaddr by writing directly into the dev->enet_addr field >> and then calling write_hwaddr() if it exists. Maybe that is ok - is >> the lack of write_hwaddr() an indication that the driver does MAC >> address handling on the fly, or just that it can't set the MAC address >> at all? >> >> Overall I feel that eth_write_hwaddr() should return success or >> failure, confident in its determination that there is either a valid >> MAC address or there is not. The message you are seeing is I suppose >> an indication that it thinks there is a problem, when in fact none >> exists in this case. At the moment it feels fragile. >> >> I wonder whether a little refactor here would be best? >> >> That said, your patch restores the original behaviour, hiding the >> problem which isn't actually a problem in this case, and which we >> don't want to report. So it is better than the status quo. > > > Ok, thanks. > > I'm not an expert for this code, nor is the patch from me. It's from Eric ;) I just try to help to mainline all the stuff we have collected for i.MX6. > > Therefore I wonder if it would be possible to split this into two steps: > > a) Improve the status quo by applying this patch > b) In parallel discuss how to refactor and improve this code as you describe above > > It's my feeling that with (a) we still have a chance to improve v2012.03. But I doubt that (b) would make it into v2012.03.
Yes agreed, it is a separate discussion. I added Wolfgang on cc to see what he thinks. Regards, Simon > > Best regards > > Dirk >
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