On Tue, Dec 4, 2018 at 5:56 PM Vignesh R vigneshr@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U-Boot SPI NOR support (sf layer) is quite outdated as it does not support 4 byte addressing opcodes, SFDP table parsing and different types of quad mode enable sequences.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. ofcourse other subsystems might have doing this but I literally don't propose to do that, since it may fire the u-boot implementation in future.
If you really get things up further, try to check this DM based spi-nor here[1] and lets discuss on u-boot point-of-view. I've paused this because of non-dm code, but I'm thinking we even re-change this to fit MTD driver-model (this is my TODO, once spi dm migration done).
[1] http://git.denx.de/?p=u-boot-spi.git;a=shortlog;h=refs/heads/next-working