[U-Boot] [PATCH 05/16] mtd: spi: Port SPI NOR framework from Linux

[Jagan Teki]

On Thu, Dec 13, 2018 at 4:26 AM Tom Rini <trini at konsulko.com> wrote:
>
> On Thu, Dec 13, 2018 at 02:01:15AM +0530, Jagan Teki wrote:
> > On Wed, Dec 12, 2018 at 11:10 PM Vignesh R <vigneshr at ti.com> wrote:
> > >
> > > Current U-Boot SPI NOR support (sf layer) is quite outdated as it does not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.
> > > So sync SPI NOR framework from Linux v4.19 and add spi-mem support on top.
> > > in order to gain 4 byte addressing support, SFDP support and a way to
> > > support SPI controllers with MMIO flash interface.
> > >
> > > Signed-off-by: Vignesh R <vigneshr at ti.com>
> > > ---
> > >  drivers/mtd/spi/spi-nor-core.c | 2647 ++++++++++++++++++++++++++++++++
> > >  include/linux/mtd/cfi.h        |   32 +
> > >  include/linux/mtd/spi-nor.h    |  421 +++++
> >
> > Please refer many mails about this comment. I don't look for carbon
> > copy of the code from Linux, you can use the implementation and even
> > macro names etc but the end code would be the code that require
> > U-Boot.
> >
> > - no __UBOOT ifdef
>
> What?  This is the exact opposite of what we're doing in several other
> areas, with a large amount of success precisely because it allows us to
> leverage developer base to catch and fix problems.  Dropping in the code
> and minor and obvious deviations make for easier re-sync.

Several areas, but not spi-flash or spi. ie what I'm maintaining from
long. I'm always looking for persistent code to be IN. May be it can't
be syn-cable but we can work it more maintainable in u-boot way like
other opensource project.  Well this is my experience with the U-Boot
project development so-far, I never ever hold any features but if
u-boot need the same features, better to add then like new code.

>
> > - file names in u-boot should have _ other than few uclass drivers
>
> There is no consistent naming scheme really.  I see ~1500 "_" C files
> and ~500 "-" files.

I have the same experience when I rename spi_flash.c with spi-flash.c.