On 13/12/18 2:55 AM, Boris Brezillon wrote: > On Wed, 12 Dec 2018 22:07:44 +0100 > Jagan Teki <ja...@amarulasolutions.com> wrote: > >> On Wed 12 Dec, 2018, 10:02 PM Boris Brezillon <boris.brezil...@bootlin.com >> wrote: >> >>> On Thu, 13 Dec 2018 02:15:16 +0530 >>> Jagan Teki <ja...@amarulasolutions.com> wrote: >>> >>>> On Thu, Dec 13, 2018 at 2:10 AM Boris Brezillon >>>> <boris.brezil...@bootlin.com> wrote: >>>>> >>>>> Hi Jagan, >>>>> >>>>> On Thu, 13 Dec 2018 01:55:08 +0530 >>>>> Jagan Teki <ja...@amarulasolutions.com> wrote: >>>>> >>>>>> On Wed, Dec 12, 2018 at 11:08 PM Vignesh R <vigne...@ti.com> >>> wrote: >>>>>>> >>>>>>> Add non DM version of SPI_MEM to support easy migration to new SPI >>> NOR >>>>>>> framework. This can be removed once DM_SPI conversion is >>> complete. >>>>>> >>>>>> Our intention to use new driver to follow dm, why we need to support >>>>>> non-dm? any usecases? >>>>> >>>>> Looks like we're having the same discussion over and over. Vignesh is >>>>> dropping spi_flash.c which AFAICT was not depending on DM_SPI, so, if >>>>> we want to keep everyone happy while getting rid of some legacy code, >>>>> that's the only solution. DM conversion is a nice goal, but it's kind >>>>> of orthogonal to what Vignesh is working on. If DM_SPI conversion >>>>> happens before the spi-nor stuff is merged (which I doubt) then this >>>>> patch can simply be dropped. >>>> >>>> spi_flash.c is a core code not a specific driver it belongs. spi-mem >>>> is new feature driver how come new driver will support legacy non-dm >>>> do we have legacy use for that(ie what I'm asking about usecase) >>> >>> I recommend that you read the spi-mem code carefully. spi-mem is not >>> driver specific, it's a thin layer on top of spi and driver *can* (but >>> are not forced to) provide optimized methods to execute spi-mem >>> operations. When that's not the case, the implementation falls back to >>> regular spi transfers. AFAIK, both DM and non-DM drivers support >>> regular spi transfers, right? So why should we depend on DM_SPI? And >>> more importantly, if we do that, that means we can't get rid of >>> spi_flash.c since some users might still have non-DM SPI drivers, which >>> in turn means we keep more legacy code for no good reasons. >>> >> >> I understand spi-mem is core file, but new code too. > > Sorry, I don't get it. > >> >> >>> You want non-DM SPI controller drivers to go away, then remove them, >>> instead of blocking other changes using this excuse. >>> >> >> Please understand uboot development flow, legacy driver can be removed if >> possible once migration expire and NEW drivers or code must be dm driven. > > Sorry, but I think you're the one misunderstanding what we are trying > to do here. Vignesh changes have simply no impact on the DM SPI > conversion you're aiming at. All Vignesh does is provide a dummy > wrapper for non-DM drivers, which would probably have been implemented > by Miquel if you had not been so insistent on your precious DM_SPI > conversion. That was not really a problem for spi-nand, as we were > adding support for a new feature. This is not the case here. SPI NORs > are already partially supported by the u-boot spi flash layer, and we > need to keep things in a working state for those that were using it and > didn't have their SPI controller drivers converted to the DM. This > leaves us 2 options: > > 1/ keep the sf_flash code as is and add a new spi-nor code base > 2/ replace spi_flash code by the spi-nor layer imported from Linux > > Vignesh chose option #2 which has the benefit of avoiding code > duplication. Given the discussion we're having right now, I'm wondering > if it wouldn't be easier to go for option #1 in order to avoid those > endless discussions... >
Boris, thanks for chiming in! This is exactly what I had in mind. To add, I did start with #1 by simply adding support for 4 byte addressing. But, then released I need spi-mem to communicate this protocol info to SPI drivers, then found Quad Enable detection logic to be incomplete and so on.. Finally released I would end up with code exactly similar to Linux SPI-NOR(with addition of SFDP logic). Therefore switched to #2 ;) -- Regards Vignesh _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
