linux-kernel - Re: [PATCH v9 00/13] media: atmel: atmel-isc: implement media controller

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Message-ID: <9111ee7f-9eb9-5da5-f65b-6e868f2e72f4@microchip.com>
Date:   Fri, 29 Apr 2022 08:20:25 +0000
From:   <Eugen.Hristev@...rochip.com>
To:     <hverkuil@...all.nl>, <linux-media@...r.kernel.org>,
        <jacopo@...ndi.org>
CC:     <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <Claudiu.Beznea@...rochip.com>, <robh+dt@...nel.org>,
        <Nicolas.Ferre@...rochip.com>
Subject: Re: [PATCH v9 00/13] media: atmel: atmel-isc: implement media
 controller

On 4/29/22 11:05 AM, Hans Verkuil wrote:
> Hi Eugen,
> 
> On 10/03/2022 10:51, Eugen Hristev wrote:
>> This series is the v9 series that attempts to support media controller in the
>> atmel ISC and XISC drivers.
>> The CSI2DC driver was accepted thus removed from the patch series, together with
>> other patches.
>>
>> Important note: this series applies on top of current media_staging tree, as it
>> relies on previous patches in the series which were accepted.
>>
>> Thanks to everyone who reviewed my work !
>>
>> Eugen
>>
>> Changes in v9:
>> -> kernel robot reported isc_link_validate is not static, changed to static.
>>
>> Changes in v8:
>> -> scaler: modified crop bounds to have the exact source size
>>
>> Changes in v7:
>> -> scaler: modified crop bounds to have maximum isc size
>> -> format propagation: did small changes as per Jacopo review
>>
>>
>> Changes in v6:
>> -> worked a bit on scaler, added try crop and other changes as per Jacopo review
>> -> worked on isc-base enum_fmt , reworked as per Jacopo review
>>
>> Changes in v5:
>> -> removed patch that removed the 'stop' variable as it was still required
>> -> added two new trivial patches
>> -> reworked some parts of the scaler and format propagation after discussions with Jacopo
>>
>>
>> Changes in v4:
>> -> as reviewed by Hans, added new patch to remove the 'stop' variable and reworked
>> one patch that was using it
>> -> as reviewed by Jacopo, reworked some parts of the media controller implementation
>>
>>
>> Changes in v3:
>> - change in bindings, small fixes in csi2dc driver and conversion to mc
>> for the isc-base.
>> - removed some MAINTAINERS patches and used patterns in MAINTAINERS
>>
>> Changes in v2:
>> - integrated many changes suggested by Jacopo in the review of the v1 series.
>> - add a few new patches
>>
>>
>>
>> Eugen Hristev (13):
>>    media: atmel: atmel-isc-base: use streaming status when queueing
>>      buffers
>>    media: atmel: atmel-isc-base: replace is_streaming call in
>>      s_fmt_vid_cap
>>    media: atmel: atmel-isc: remove redundant comments
>>    media: atmel: atmel-isc: implement media controller
>>    media: atmel: atmel-sama5d2-isc: fix wrong mask in YUYV format check
>>    media: atmel: atmel-isc-base: use mutex to lock awb workqueue from
>>      streaming
>>    media: atmel: atmel-isc: compact the controller formats list
>>    media: atmel: atmel-isc: change format propagation to subdev into only
>>      verification
>>    media: atmel: atmel-sama7g5-isc: remove stray line
>>    dt-bindings: media: microchip,xisc: add bus-width of 14
> 
> I'm a bit unhappy with the order of these patches. Mostly these are fixes,
> except for patches 4 and 8, which are the meat of this series and actually
> switching on the MC support.
> 
> Can those be moved to the end? That also makes it easier to merge the earlier
> patches if some more work is needed for the MC part.
> 
> I'm also not sure whether patches 4 and 8 shouldn't be a single patch,
> since patch 4 leaves the driver in an inconsistent state since it is
> missing the link validation code that patch 8 adds. Unless I missed
> something?

Hello Hans,

The difference that patch 8 is making is that the 'old way' of 
configuring the ISC is no longer possible.

Patch 4 makes the ISC 'mc-ready' with all entities, links, but the old 
way still works (meaning that the top driver will call s_fmt down to the 
subdev ).
After patch 8, the driver no longer has this support at all, and 
validates links at start_streaming, and no longer sets anything to the 
subdev, just validates the config that the subdev already has.
So one reason that I had things in two patches was that patch 8 makes 
this big change that also makes userspace behave differently and has to 
configure all the subdevs and media pipeline.

If you feel patch 4 and patch 8 should be squashed, I can do it, definitely.

Let me know how to proceed ?

Thanks,
Eugen

> 
> Regards,
> 
>          Hans
> 
>>    ARM: dts: at91: sama7g5: add nodes for video capture
>>    ARM: configs: at91: sama7: add xisc and csi2dc
>>    ARM: multi_v7_defconfig: add atmel video pipeline modules
>>
>>   .../bindings/media/microchip,xisc.yaml        |   2 +-
>>   arch/arm/boot/dts/sama7g5.dtsi                |  49 ++
>>   arch/arm/configs/multi_v7_defconfig           |   3 +
>>   arch/arm/configs/sama7_defconfig              |   2 +
>>   drivers/media/platform/atmel/Makefile         |   2 +-
>>   drivers/media/platform/atmel/atmel-isc-base.c | 518 ++++++++++--------
>>   .../media/platform/atmel/atmel-isc-scaler.c   | 267 +++++++++
>>   drivers/media/platform/atmel/atmel-isc.h      |  58 +-
>>   .../media/platform/atmel/atmel-sama5d2-isc.c  |  87 +--
>>   .../media/platform/atmel/atmel-sama7g5-isc.c  |  93 ++--
>>   10 files changed, 754 insertions(+), 327 deletions(-)
>>   create mode 100644 drivers/media/platform/atmel/atmel-isc-scaler.c
>>
>