[U-Boot] is it mandatory for SPL to support DM

[Marek Vasut]

On 5/25/20 7:32 PM, Tom Rini wrote:
> On Mon, May 25, 2020 at 10:58:12PM +0530, Jagan Teki wrote:
>> On Mon, May 25, 2020 at 9:06 PM Simon Glass <sjg at chromium.org> wrote:
>>>
>>> Hi,
>>>
>>> On Mon, 25 May 2020 at 04:35, Marek Vasut <marex at denx.de> wrote:
>>>>
>>>> On 5/25/20 10:44 AM, Jagan Teki wrote:
>>>>> SPL has a foot-print constraint, so fully switching a particular
>>>>> subsystem like SPI or SPI Flash to DM would increase the size of it.
>>>>>
>>>>> Possible areas to look at are (assume SPL_DM supported)
>>>>> 1) platdata
>>>>> 2) implement board or platform specific spl device driver which
>>>>> bypassed the actual framework ex: spl_spi_sunxi.c
>>>>>
>>>>> Do we have any other solutions? or any arguments on above step 2?
>>>>
>>>> SPL does not need to support DM until the size problem is solved.
>>>
>>> I don't think the problem will ever be 'solved'. It is an ongoing battle.
>>>
>>> But as it happens I've just sent a proposal for tiny-dm that I think will help.
>>>
>>> Jagan, which board are you trying to convert? If you are trying to
>>> convert SPI flash, I think we need to remove the legacy code first.
>>
>> These are the partially dm converted drivers, so boards which are
>> using can eventually need a dm spi switch.
>>
>>         drivers/spi/fsl_dspi.c
>>         drivers/spi/kirkwood_spi.c
>>         drivers/spi/mxc_spi.c
>>         drivers/spi/mxs_spi.c
>>         drivers/spi/omap3_spi.c
>>         drivers/spi/sh_qspi.c
>>
>> I'm looking for proper options along with removal of some legacy code,
>> and tiny-dm.
> 
> For the number of about to be year past published deadline (which has
> been extended at times to get to that point even) boards, I think we
> need to start by dropping boards.  Then we can see what makes sense
> moving forward.

At least mxc_spi and sh_qspi must stay, since those are heavily used in
embedded/industrial/automotive.