[PATCH 3/4] mtd/fpga: add fpga directory to mtd (with Cyclone 10)

[Steffen Dirkwinkel]

> On 23. Feb 2023, at 09:28, Ulf Samuelsson <u-boot at emagii.com> wrote:
>
> CAUTION: External Email!!
>
>
>
> On 2023-02-22 20:51, Steffen Dirkwinkel wrote:
>> Hi!
>> On Tue, 2023-02-21 at 11:58 +0100, Ulf Samuelsson wrote:
>>> CAUTION: External Email!!
>>> Hi Guys,
>>> We are currently discussing how to support passive serial configuration
>>> of FPGAs in u-boot.
>>>
>>> Checking the u-boot source code reveals that only your boards
>>> actually supports this.
>>>
>>> board/beckhoff/mx53cx9020/mx53cx9020.c:...Altera_CYC2_Passive_Serial ...
>>> $ scripts/get_maintainer.pl board/beckhoff/mx53cx9020/mx53cx9020.c
>>> Patrick Bruenn <p.bruenn at beckhoff.com> (maintainer:MX53 CX9020)
>> This doesn't seem immediately relevant to our board as we don't really use spi,
>> but the (w)eim interface as far as i can tell right now. (has been a while since I looked
>> at it, have not read the imx datasheet again to see if this is spi in disguise)
>> If anything the binding should be shared between u-boot and the kernel. We just had a bug
>> because of differences between the two.
>> Something like the "altr,fpga-passive-serial" in arch/arm/boot/dts/imx6q-evi.dts in the kernel would match the
>> usecase.
>> We wouldn't be opposed to changing the dt and also just repaired our CI for these devices and can test changes quickly.
> I had a look at your code again.
> It appears that you are using the Altera "passive serial" interface in U-Boot, but your board routine appears to write 8-bit bytes to the external bus.
>
> The only two reasons for this I can think of is that you are either
> using an external serializer converting the 8 bit words to
> a serial stream or you are actually using the passive "parallell
> interface" on the FPGA, but use the "passive serial" routines
> in u-boot.
>
> Can you please confirm how the hardware works?

I checked the schematic, we’re using fast_passive_parallel.
Since both are using the same codepaths right now it didn’t matter. I’ll send a patch

>
>
> The maintainer of the other board using "passive serial" (w.wegner at astro-kom.de <w.wegner at astro-kom.de>)
> bounced as an unknown user.  This means that the "board/astro/mcf5373" does not have an active MAINTAINER.
>
> The board was added in 2010, and has not seen any updates from
> https://nospamproxywebp.beckhoff.com/enqsig/link?id=BCAAAABGd7m3lfMOLOIhx3uNR_1Qav4Ffx8-jQB0torD82ts_G8AAAB_Q13kS5en5WiHBszxeeaYjAQwTPXiCeF8gx_zVjByVYRebkfOfUTW4VnpSmQ2VlvWczqoVxWwP7qF1C4VccAGIB-3QCgtp-eMVgM5VcCkSRCJT8HehzvaoUnQ6YYu2ofkD0GMhgmICiFDb8Cv_2k1  since then. All the maintenance has been by people maintaining subsystems.
>
> Best Regards
> Ulf Samuelsson
>
>
>> Best Regards
>> Steffen Dirkwinkel
>>>
>>> board/astro/mcf5373l/fpga.c:Altera_CYC2_Passive_Serial ...
>>> $ scripts/get_maintainer.pl board/astro/mcf5373l/fpga.c
>>> Wolfgang Wegner <w.wegner at astro-kom.de> (maintainer:MCF5373L BOARD)
>>>
>>> The proposed ideas is to have the FPGA as an SPI peripheral
>>> in the device tree.
>>>
>>> I have a working version, where the FPGA is an MTD device
>>> and the general idea is to add it to the FPGA manager,
>>> which unfortunately needs a major rewrite to support device tree.
>>>
>>> Your board support configuring the FPGA in the 'board' files.
>>>
>>>
>>> * Are these boards still active and will require updates of u-boot?
>>>
>>> * If so, would it be a problem porting the FPGA configuration to the
>>> device tree?
>>>
>>> Marek does not want two drivers supporting passive serial,
>>> and supporting both 'board' drivers and devicetree drivers
>>> seems to result in unclean code.
>>>
>>> Best Regards
>>> Ulf Samuelsson
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>> Beckhoff Automation GmbH & Co. KG | Managing Director: Dipl. Phys. Hans Beckhoff
>> Registered office: Verl, Germany | Register court: Guetersloh HRA 7075


This email contains confidential information. If you have received it in error, you must not read, use, copy or pass on this e-mail or its attachments. If you have received the e-mail in error, please inform me immediately by reply e-mail and then delete this e-mail from your system. Thank you

Diese E-Mail enthält vertrauliche Informationen. Sollten Sie sie irrtümlich erhalten haben, dürfen Sie diese E-Mail oder ihre Anhänge nicht lesen, verwenden, kopieren oder weitergeben. Sollten Sie die Mail versehentlich erhalten haben, teilen Sie mir dies bitte umgehend per Antwort-E-Mail mit und löschen Sie diese E-Mail dann aus Ihrem System. Vielen Dank

Beckhoff Automation GmbH & Co. KG | Managing Director: Dipl. Phys. Hans Beckhoff
Registered office: Verl, Germany | Register court: Guetersloh HRA 7075