Re: [PATCH 02/32] spi: dw: Add support for 32-bits ctrlr0 layout

Andy Shevchenko
2020-11-09T14:40:55Z

On Mon, Nov 9, 2020 at 4:40 PM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Mon, Nov 9, 2020 at 4:34 PM Sean Anderson <seanga2@gmail.com> wrote:
> > On 11/9/20 9:25 AM, Serge Semin wrote:
> > > On Sat, Nov 07, 2020 at 05:13:50PM +0900, Damien Le Moal wrote:
>
> ...
>
> > > Are you sure they have been moved from [0, 3] to [16, 20]? I don't have the
> > > manual for the 4.0x version of the core, but according to this patch:
> > > https://patchwork.kernel.org/project/spi-devel-general/patch/1575907443-26377-7-git-send-email-wan.ahmad.zainie.wan.mohamad@intel.com/
> > > it has been ok to use the lowest four bits for DFS setting. Is the commit
> > > message misleading there?
> >
> > This commit message is a truncated version of [1].
>
> I don't see how they are related.

For DW_ssi v1.x DFS is always for transfers up to 32-bit.

> > Importantly, DFS is
> > valid when SSI_MAX_XFER_SIZE=16. When it =32, then DFS_32 must be used
> > (since DFS is constant 0xF). Since SSI_MAX_XFER_SIZE is a synthesis
> > parameter, there exist devices where DFS must be used, and also where
> > DFS_32 must be used.
> >
> > [1] https://patchwork.ozlabs.org/project/uboot/patch/20201016225755.302659-10-seanga2@gmail.com/

--
With Best Regards,
Andy Shevchenko