Re: [PATCH 00/16] mtd: spi-nor: aspeed: AST2600 support and extensions

[Joel Stanley <joel@xxxxxxxxx>]

On Wed, 9 Oct 2019 at 20:56, Boris Brezillon
<boris.brezillon@xxxxxxxxxxxxx> wrote:
>
> Hi Cedric,
>
> On Fri,  4 Oct 2019 13:59:03 +0200
> Cédric Le Goater <clg@xxxxxxxx> wrote:
>
> > Hello,
> >
> > This series first extends the support for the Aspeed AST2500 and
> > AST2400 SMC driver. It adds Dual Data support and read training giving
> > the best read settings for a given chip. Support for the new AST2600
> > SoC is added at the end.
> >
> > I understand that a new spi_mem framework exists and I do have an
> > experimental driver using it. But unfortunately, it is difficult to
> > integrate the read training. The Aspeed constraints are not compatible
> > and i haven't had the time to extend the current framework.
>
> Hm, I don't think that's a good reason to push new features to the
> existing driver, especially since I asked others to migrate their
> drivers to spi-mem in the past. I do understand your concerns, and I'll
> let the SPI NOR/MTD maintainers make the final call, but I think it'd
> be better for the SPI MEM ecosystem to think about this link-training
> API (Vignesh needs it for the Cadence driver IIRC) rather than pushing
> this kind of feature to spi-nor controller drivers.

As Cedric mentioned, the OpenBMC project has been shipping the read
training code for the ast2400/ast2400 for several years now. It would
be great to see it in mainline.

I think it's reasonable to ask for the driver to be moved to the
spi-mem subsystem once it has the required APIs.

Cheers,

Joel


>
> >
> > This patchset has been in use for some time in the OpenBMC kernel on
> > these systems :
> >
> >  * OpenPOWER Palmetto (AST2400)
> >  * Evaluation board (AST2500)
> >  * OpenPOWER Witherspoon (AST2500)
> >  * OpenPOWER Romulus (AST2500)
> >  * OpenPOWER Zaius (AST2500)
> >    and many others
> >
> > and it is now in use on these boards with the new SoC :
> >
> >  * Evaluation board (AST2600)
> >  * Tacoma board (AST2600)
> >
> > Thanks,
> >
> > C.
> >
> > Alexander Soldatov (1):
> >   mtd: spi-nor: fix options for mx66l51235f
> >
> > Cédric Le Goater (15):
> >   mtd: spi-nor: aspeed: Use command mode for reads
> >   mtd: spi-nor: aspeed: Add support for SPI dual IO read mode
> >   mtd: spi-nor: aspeed: Link controller with the ahb clock
> >   mtd: spi-nor: aspeed: Add read training
> >   mtd: spi-nor: aspeed: Limit the maximum SPI frequency
> >   mtd: spi-nor: aspeed: Add support for the 4B opcodes
> >   mtd: spi-nor: Add support for w25q512jv
> >   mtd: spi-nor: aspeed: Introduce a field for the AHB physical address
> >   mtd: spi-nor: aspeed: Introduce segment operations
> >   dt-bindings: mtd: aspeed-smc: Add new comptatible for AST2600
> >   mtd: spi-nor: aspeed: Add initial support for the AST2600
> >   mtd: spi-nor: aspeed: Check for disabled segments on the AST2600
> >   mtd: spi-nor: aspeed: Introduce training operations per platform
> >   mtd: spi-nor: aspeed: Introduce a HCLK mask for training
> >   mtd: spi-nor: aspeed: Add read training support for the AST2600
> >
> >  drivers/mtd/spi-nor/aspeed-smc.c              | 593 ++++++++++++++++--
> >  drivers/mtd/spi-nor/spi-nor.c                 |   5 +-
> >  .../devicetree/bindings/mtd/aspeed-smc.txt    |   2 +
> >  3 files changed, 551 insertions(+), 49 deletions(-)
> >
>

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