On 07/12/18 3:21 PM, Boris Brezillon wrote: > On Thu, 6 Dec 2018 23:55:30 +0530 > Vignesh R <vigne...@ti.com> wrote: > >> On 06-Dec-18 10:44 PM, Jagan Teki wrote: >>> On Tue, Dec 4, 2018 at 5:56 PM Vignesh R <vigne...@ti.com> wrote: >>>> >>>> U-Boot SPI NOR support (sf layer) is quite outdated as it does not >>>> support 4 byte addressing opcodes, SFDP table parsing and different types >>>> of >>>> quad mode enable sequences. Many newer flashes no longer support BANK >>>> registers used by sf layer to a access >16MB space. >>>> Also, many SPI controllers have special MMIO interfaces which provide >>>> accelerated read/write access but require knowledge of flash parameters >>>> to make use of it. Recent spi-mem layer provides a way to support such >>>> flashes but sf layer isn't using that. >>>> This patch series syncs SPI NOR framework from Linux v4.19. It also adds >>>> spi-mem support on top. >>>> So, we gain 4byte addressing support and SFDP support. This makes >>>> migrating to U-Boot MTD framework easier. >>> >>> We(someone) has proposed this sync before, but we(at-least I) rely on >>> implementing via DM not direct sync to Linux. >> >> As I said in my cover letter, U-Boot sf layer is unable to support newer >> flashes mainly due to lack of 4 byte addressing and proper support for >> MMIO capable SPI controllers. >> My idea of fixing this is to borrow _features_ from Linux SPI NOR "as >> is". All that's needed is stateless 4 byte addressing, SFDP >> parsing(optionally), Quad/Octal support and spi-mem like abstraction for >> MMIO capable Controllers. I see no point in re-coding them from ground up. >> >> Could you be more specific on what you would like to see here in DM way? >> I have no issues in adapting this code to any framework here in U-Boot. >> Linux has driver model and SPI NOR subsystem is a framework and >> therefore any code ported from Linux will inherently have those >> abstractions. The only difference I see wrt your code in branch below vs >> this series is SPI-NOR uclass. This can be easily achieved by moving >> nor->ops out of struct spi_nor into uclass abstraction. >> Upstream Linux is anyways merging m25p80 and spi-nor so I did not see a >> need for SPI NOR uclass. I am okay to change that if you insist on >> having it. >> > > No, please don't add a SPI_NOR_UCLASS. We already have the MTD_UCLASS > which is barely used by drivers, so if anything, we should work on > converting drivers to this UCLASS and maybe automate a few more things > for MTD drivers (like MTD dev registration/deregistration [1]) instead > of adding yet another UCLASS. >
I agree. > If you need an example of how integration with the DM (and the MTD > UCLASS) should be been done, you can look at the SPI NAND driver [2]. > > [1]http://code.bulix.org/9lart9-519406 > [2]http://git.denx.de/?p=u-boot.git;a=blob;f=drivers/mtd/nand/spi/core.c;h=cb8ffa3fa96a16dd40dda3553bbb171107e71df7;hb=HEAD#l1249 > Yeah, that can be done once MTD Kconfig cleanup is done and we have dropped UCLASS_SPI_FLASH (would also require sf_dataflash.c to be moved to MTD) -- Regards Vignesh _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot