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[v4,00/11] media: atmel: atmel-isc: implement media controller

Message ID 20220121131416.603972-1-eugen.hristev@microchip.com
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Series media: atmel: atmel-isc: implement media controller | expand

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Eugen Hristev Jan. 21, 2022, 1:14 p.m. UTC
This series is the v4 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.

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

Thanks to everyone who reviewed my work !

Eugen


Previous cover letter from v3:

This series is the v3 of the series that attempts to support media controller
in the atmel ISC and XISC drivers.
This series also includes the csi2dc driver which was previously sent in a
separate series:
https://www.spinics.net/lists/linux-media/msg181042.html
https://www.spinics.net/lists/linux-media/msg181044.html
The driver now addresses comments received in latest v5 series from last year.

The series includes some minor changes and fixes that improve the isc common
code base, like removing the enum frameintervals VIDIOC, fixing bytesperline
for planar formats, etc.

Many thanks to folks from libcamera who helped a lot with understanding
how a media controller driver should behave.

Feedback is welcome !

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 (11):
  media: atmel: atmel-isc: replace 'stop' variable with vb2 calls
  media: atmel: atmel-isc-base: use streaming status when queueing
    buffers
  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
  dt-bindings: media: microchip,xisc: add bus-width of 14
  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 | 455 +++++++++++-------
 .../media/platform/atmel/atmel-isc-scaler.c   | 250 ++++++++++
 drivers/media/platform/atmel/atmel-isc.h      |  43 +-
 .../media/platform/atmel/atmel-sama5d2-isc.c  |  67 ++-
 .../media/platform/atmel/atmel-sama7g5-isc.c  |  72 ++-
 10 files changed, 694 insertions(+), 251 deletions(-)
 create mode 100644 drivers/media/platform/atmel/atmel-isc-scaler.c

Comments

Eugen Hristev Feb. 8, 2022, 10:33 a.m. UTC | #1
On 2/8/22 10:59 AM, Jacopo Mondi wrote:
> Hi Eugen
> 
> On Mon, Feb 07, 2022 at 01:40:31PM +0000, Eugen.Hristev@microchip.com wrote:
>> On 2/7/22 2:44 PM, Jacopo Mondi wrote:
>>> Hi Eugen
>>>
>>> On Fri, Jan 21, 2022 at 03:14:08PM +0200, Eugen Hristev wrote:
>>>> Implement the support for media-controller.
>>>> This means that the capabilities of the driver have changed and now
>>>> it also advertises the IO_MC .
>>>> The driver will register it's media device, and add the video entity to this
>>>> media device. The subdevices are registered to the same media device.
>>>> The ISC will have a base entity which is auto-detected as atmel_isc_base.
>>>> It will also register a subdevice that allows cropping of the incoming frame
>>>> to the maximum frame size supported by the ISC.
>>>> The ISC will create a link between the subdevice that is asynchronously
>>>> registered and the atmel_isc_scaler entity.
>>>> Then, the atmel_isc_scaler and atmel_isc_base are connected through another
>>>> link.
>>>>
>>>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
>>>> ---
>>>> Changes in v4:
>>>> As suggested by Jacopo:
>>>> - renamed atmel_isc_mc to atmel_isc_scaler.c
>>>> - moved init_mc/clean_mc to isc_base file
>>>>
>>>> Changes in v2:
>>>> - implement try formats
>>>>
>>>>    drivers/media/platform/atmel/Makefile         |   2 +-
>>>>    drivers/media/platform/atmel/atmel-isc-base.c |  73 +++++-
>>>>    .../media/platform/atmel/atmel-isc-scaler.c   | 245 ++++++++++++++++++
>>>>    drivers/media/platform/atmel/atmel-isc.h      |  37 +++
>>>>    .../media/platform/atmel/atmel-sama5d2-isc.c  |  14 +-
>>>>    .../media/platform/atmel/atmel-sama7g5-isc.c  |  12 +-
>>>>    6 files changed, 375 insertions(+), 8 deletions(-)
>>>>    create mode 100644 drivers/media/platform/atmel/atmel-isc-scaler.c
>>>>
>>>> diff --git a/drivers/media/platform/atmel/Makefile b/drivers/media/platform/atmel/Makefile
>>>> index 794e8f739287..f02d03df89d6 100644
>>>> --- a/drivers/media/platform/atmel/Makefile
>>>> +++ b/drivers/media/platform/atmel/Makefile
>>>> @@ -1,7 +1,7 @@
>>>>    # SPDX-License-Identifier: GPL-2.0-only
>>>>    atmel-isc-objs = atmel-sama5d2-isc.o
>>>>    atmel-xisc-objs = atmel-sama7g5-isc.o
>>>> -atmel-isc-common-objs = atmel-isc-base.o atmel-isc-clk.o
>>>> +atmel-isc-common-objs = atmel-isc-base.o atmel-isc-clk.o atmel-isc-scaler.o
>>>>
>>>>    obj-$(CONFIG_VIDEO_ATMEL_ISI) += atmel-isi.o
>>>>    obj-$(CONFIG_VIDEO_ATMEL_ISC_BASE) += atmel-isc-common.o
>>>> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
>>>> index 6b0005987a17..6b482270eb93 100644
>>>> --- a/drivers/media/platform/atmel/atmel-isc-base.c
>>>> +++ b/drivers/media/platform/atmel/atmel-isc-base.c
>>>> @@ -1710,6 +1710,7 @@ static int isc_async_bound(struct v4l2_async_notifier *notifier,
>>>>                                               struct isc_device, v4l2_dev);
>>>>         struct isc_subdev_entity *subdev_entity =
>>>>                 container_of(notifier, struct isc_subdev_entity, notifier);
>>>> +     int pad;
>>>>
>>>>         if (video_is_registered(&isc->video_dev)) {
>>>>                 v4l2_err(&isc->v4l2_dev, "only supports one sub-device.\n");
>>>> @@ -1718,6 +1719,16 @@ static int isc_async_bound(struct v4l2_async_notifier *notifier,
>>>>
>>>>         subdev_entity->sd = subdev;
>>>>
>>>> +     pad = media_entity_get_fwnode_pad(&subdev->entity, asd->match.fwnode,
>>>> +                                       MEDIA_PAD_FL_SOURCE);
>>>> +     if (pad < 0) {
>>>> +             v4l2_err(&isc->v4l2_dev, "failed to find pad for %s\n",
>>>> +                      subdev->name);
>>>> +             return pad;
>>>> +     }
>>>> +
>>>> +     isc->remote_pad = pad;
>>>> +
>>>>         return 0;
>>>>    }
>>>>
>>>> @@ -1732,8 +1743,8 @@ static void isc_async_unbind(struct v4l2_async_notifier *notifier,
>>>>         v4l2_ctrl_handler_free(&isc->ctrls.handler);
>>>>    }
>>>>
>>>> -static struct isc_format *find_format_by_code(struct isc_device *isc,
>>>> -                                           unsigned int code, int *index)
>>>> +struct isc_format *isc_find_format_by_code(struct isc_device *isc,
>>>> +                                        unsigned int code, int *index)
>>>>    {
>>>>         struct isc_format *fmt = &isc->formats_list[0];
>>>>         unsigned int i;
>>>> @@ -1749,6 +1760,7 @@ static struct isc_format *find_format_by_code(struct isc_device *isc,
>>>>
>>>>         return NULL;
>>>>    }
>>>> +EXPORT_SYMBOL_GPL(isc_find_format_by_code);
>>>>
>>>>    static int isc_formats_init(struct isc_device *isc)
>>>>    {
>>>> @@ -1765,7 +1777,7 @@ static int isc_formats_init(struct isc_device *isc)
>>>>                NULL, &mbus_code)) {
>>>>                 mbus_code.index++;
>>>>
>>>> -             fmt = find_format_by_code(isc, mbus_code.code, &i);
>>>> +             fmt = isc_find_format_by_code(isc, mbus_code.code, &i);
>>>>                 if (!fmt) {
>>>>                         v4l2_warn(&isc->v4l2_dev, "Mbus code %x not supported\n",
>>>>                                   mbus_code.code);
>>>> @@ -1891,7 +1903,8 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
>>>>         vdev->queue             = q;
>>>>         vdev->lock              = &isc->lock;
>>>>         vdev->ctrl_handler      = &isc->ctrls.handler;
>>>> -     vdev->device_caps       = V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE;
>>>> +     vdev->device_caps       = V4L2_CAP_STREAMING | V4L2_CAP_VIDEO_CAPTURE |
>>>> +                               V4L2_CAP_IO_MC;
>>>>         video_set_drvdata(vdev, isc);
>>>>
>>>>         ret = video_register_device(vdev, VFL_TYPE_VIDEO, -1);
>>>> @@ -1901,8 +1914,18 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
>>>>                 goto isc_async_complete_err;
>>>>         }
>>>>
>>>> +     ret = isc_scaler_link(isc);
>>>> +     if (ret < 0)
>>>> +             goto isc_async_complete_unregister_device;
>>>> +
>>>> +     ret = media_device_register(&isc->mdev);
>>>> +     if (ret < 0)
>>>> +             goto isc_async_complete_unregister_device;
>>>>         return 0;
>>>>
>>>> +isc_async_complete_unregister_device:
>>>> +     video_unregister_device(vdev);
>>>> +
>>>>    isc_async_complete_err:
>>>>         mutex_destroy(&isc->lock);
>>>>         return ret;
>>>> @@ -1969,6 +1992,48 @@ int isc_pipeline_init(struct isc_device *isc)
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(isc_pipeline_init);
>>>>
>>>> +int isc_mc_init(struct isc_device *isc, u32 ver)
>>>> +{
>>>> +     const struct of_device_id *match;
>>>> +     int ret;
>>>> +
>>>> +     isc->video_dev.entity.function = MEDIA_ENT_F_IO_V4L;
>>>> +     isc->video_dev.entity.flags = MEDIA_ENT_FL_DEFAULT;
>>>
>>> Should you set entity.ops.link_validate = v4l2_subdev_link_validate
>>> to be able to have the media pipeline validated at
>>> media_pipeline_start() time ?
>>
>> Hi,
>>
>> I am doing that in a subsequent patch. Things are not completely ready
>> at this moment, because ISC still relies on the old mechanism to call
>> v4l2_subdev_call with set_fmt on the subdevice (which subsequent patch
>> removes and adds checks to the link validate ).
>>
> 
> I see.. the subsequent patches are not part of this series, right ?

No. Patch 7 does this. In that patch, the link validation is created and 
all the logic of format propagation is removed and reworked, and creates 
the need for the link_validate call
Could you have also a look at that patch ?
> 
> I think patches 1, 2, 4, 5 and 6 from this series do not depend on
> the introduction of media controller or the scaler, right ? (I'm not
> sure if the DTS patches do).
> 
> If that's the case, would it make sense to to fast-track them (as some
> of them are fixes) and then on top plumb the media controller
> infrastructure with this patch and the ones you have been mentioning ?

It would make sense.

> 
>>>
>>>> +     isc->pads[ISC_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>>>> +
>>>> +     ret = media_entity_pads_init(&isc->video_dev.entity, ISC_PADS_NUM,
>>>> +                                  isc->pads);
>>>> +     if (ret < 0) {
>>>> +             dev_err(isc->dev, "media entity init failed\n");
>>>> +             return ret;
>>>> +     }
>>>> +
>>>> +     isc->mdev.dev = isc->dev;
>>>> +
>>>> +     match = of_match_node(isc->dev->driver->of_match_table,
>>>> +                           isc->dev->of_node);
>>>> +
>>>> +     strscpy(isc->mdev.driver_name, KBUILD_MODNAME,
>>>> +             sizeof(isc->mdev.driver_name));
>>>> +     strscpy(isc->mdev.model, match->compatible, sizeof(isc->mdev.model));
>>>> +     snprintf(isc->mdev.bus_info, sizeof(isc->mdev.bus_info), "platform:%s",
>>>> +              isc->v4l2_dev.name);
>>>> +     isc->mdev.hw_revision = ver;
>>>> +
>>>> +     media_device_init(&isc->mdev);
>>>> +
>>>> +     isc->v4l2_dev.mdev = &isc->mdev;
>>>> +
>>>> +     return isc_scaler_init(isc);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(isc_mc_init);
>>>> +
>>>> +void isc_mc_cleanup(struct isc_device *isc)
>>>> +{
>>>> +     media_entity_cleanup(&isc->video_dev.entity);
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(isc_mc_cleanup);
>>>> +
>>>>    /* regmap configuration */
>>>>    #define ATMEL_ISC_REG_MAX    0xd5c
>>>>    const struct regmap_config isc_regmap_config = {
>>>> diff --git a/drivers/media/platform/atmel/atmel-isc-scaler.c b/drivers/media/platform/atmel/atmel-isc-scaler.c
>>>> new file mode 100644
>>>> index 000000000000..ec95c9665883
>>>> --- /dev/null
>>>> +++ b/drivers/media/platform/atmel/atmel-isc-scaler.c
>>>> @@ -0,0 +1,245 @@
>>>> +// SPDX-License-Identifier: GPL-2.0-only
>>>> +/*
>>>> + * Microchip Image Sensor Controller (ISC) Scaler entity support
>>>> + *
>>>> + * Copyright (C) 2021 Microchip Technology, Inc.
>>>
>>> Time flies! It's 2022 already :)
>>>
>>>> + *
>>>> + * Author: Eugen Hristev <eugen.hristev@microchip.com>
>>>> + *
>>>> + */
>>>> +
>>>> +#include <media/media-device.h>
>>>> +#include <media/media-entity.h>
>>>> +#include <media/v4l2-device.h>
>>>> +#include <media/v4l2-subdev.h>
>>>> +
>>>> +#include "atmel-isc-regs.h"
>>>> +#include "atmel-isc.h"
>>>> +
>>>> +static int isc_scaler_get_fmt(struct v4l2_subdev *sd,
>>>> +                           struct v4l2_subdev_state *sd_state,
>>>> +                           struct v4l2_subdev_format *format)
>>>> +{
>>>> +     struct isc_device *isc = container_of(sd, struct isc_device, scaler_sd);
>>>> +     struct v4l2_mbus_framefmt *v4l2_try_fmt;
>>>> +
>>>> +     if (format->which == V4L2_SUBDEV_FORMAT_TRY) {
>>>> +             v4l2_try_fmt = v4l2_subdev_get_try_format(sd, sd_state,
>>>> +                                                       format->pad);
>>>> +             format->format = *v4l2_try_fmt;
>>>> +
>>>> +             return 0;
>>>> +     }
>>>> +
>>>> +     format->format = isc->scaler_format;
>>>
>>> isc->scaler_format is only used inside this file if I'm not mistaken.
>>> I wonder why it lives in the isc_device struct.
>>
>> isc_device is a placeholder for all isc things.
>>
>> I would not create a separate struct in this file that would have to be
>> allocated etc... just for one two things. So I preferred to have it in
>> the same place as all the other things.
>>
>>>
>>>> +
>>>> +     return 0;
>>>> +}
>>>> +
>>>> +static int isc_scaler_set_fmt(struct v4l2_subdev *sd,
>>>> +                           struct v4l2_subdev_state *sd_state,
>>>> +                           struct v4l2_subdev_format *req_fmt)
>>>> +{
>>>> +     struct isc_device *isc = container_of(sd, struct isc_device, scaler_sd);
>>>> +     struct v4l2_mbus_framefmt *v4l2_try_fmt;
>>>> +     struct isc_format *fmt;
>>>> +     unsigned int i;
>>>> +
>>>> +     if (req_fmt->pad == ISC_SCALER_PAD_SOURCE)
>>>> +             v4l_bound_align_image
>>>> +                     (&req_fmt->format.width, 16, isc->max_width, 0,
>>>> +                      &req_fmt->format.height, 16, isc->max_height, 0, 0);
>>>> +     else
>>>> +             v4l_bound_align_image
>>>> +                     (&req_fmt->format.width, 16, 10000, 0,
>>>> +                      &req_fmt->format.height, 16, 10000, 0, 0);
>>>
>>> Where does 10000 come from ?
>>
>> It's a random number. Do you have any suggestion for a better one ?
> 
> An actual HW limit ? :)

There is no hardware limit. The ISC just stops sampling pixels once the 
crop limit is reached. The element that generates pixels could go on 
forever , or until the next HBLANK/VBLANK. So what limit could I place 
here ?
The cropping is mandatory, otherwise there could be an overflow w.r.t. 
the buffer size if the ISC would sample more pixels than the software 
expects it to.

> 
>> Maybe this would be much more clear with my comments below (where I will
>> explain what the isc scaler does )
>> In short, it allows the other entity in the link to 'sink' a huge format
>> into this 'scaler' . Because the scaler can crop anything basically down
>> to the biggest format size the ISC could handle.
>>
> 
> doesn't it have any documented input size limit ?

As stated above, ISC handles a pixel stream and stores it in an internal 
SRAM. ISC stops sampling when this SRAM is full or when the cropping 
limit is reached.
After storing the pixels in the SRAM (which is limited to the ISC 
maximum frame size), the ISC will work on the pixels and then DMA the 
frame to another RAM.

> 
>>>
>>>> +
>>>> +     req_fmt->format.colorspace = V4L2_COLORSPACE_SRGB;
>>>> +     req_fmt->format.field = V4L2_FIELD_NONE;
>>>> +     req_fmt->format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
>>>> +     req_fmt->format.quantization = V4L2_QUANTIZATION_DEFAULT;
>>>> +     req_fmt->format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
>>>> +
>>>> +     fmt = isc_find_format_by_code(isc, req_fmt->format.code, &i);
>>>
>>> So you rely on the isc format list for the scaler as well ?
>>> I think it's fine as long as they are identical
>>
>> Yes, the scaler is kind of a dummy entity , but it's required by the
>> media controller validation of the pipeline.
>>
> 
> More on this later
> 
>>>
>>>> +
>>>> +     if (!fmt)
>>>> +             fmt = &isc->formats_list[0];
>>>> +
>>>> +     req_fmt->format.code = fmt->mbus_code;
>>>> +
>>>> +     if (req_fmt->which == V4L2_SUBDEV_FORMAT_TRY) {
>>>> +             v4l2_try_fmt = v4l2_subdev_get_try_format(sd, sd_state,
>>>> +                                                       req_fmt->pad);
>>>> +             *v4l2_try_fmt = req_fmt->format;
>>>> +             /* Trying on the pad sink makes the source sink change too */
>>>> +             if (req_fmt->pad == ISC_SCALER_PAD_SINK) {
>>>> +                     v4l2_try_fmt =
>>>> +                             v4l2_subdev_get_try_format(sd, sd_state,
>>>> +                                                        ISC_SCALER_PAD_SOURCE);
>>>> +                     *v4l2_try_fmt = req_fmt->format;
>>>> +
>>>> +                     v4l_bound_align_image(&v4l2_try_fmt->width,
>>>> +                                           16, isc->max_width, 0,
>>>> +                                           &v4l2_try_fmt->height,
>>>> +                                           16, isc->max_height, 0, 0);
>>>> +             }
>>>> +             /* if we are just trying, we are done */
>>>> +             return 0;
>>>> +     }
>>>> +
>>>> +     isc->scaler_format = req_fmt->format;
>>>
>>> No per-pad format but a global scaler_format ? How do you configure scaling ?
>>>
>>> Actually, I would like to know more about the scaler device
>>> capabilities. What functions can this IP perform ? Does it do
>>> cropping, can it also do (down)scaling or even composition ?
>>>
>>> I think it is worth to read
>>> https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/dev-subdev.html#v4l2-subdev-selections
>>> where it is reported how cropping and scaling are implemented by using
>>> the selection API.
>>>
>>> Figure 4.5 is particularly helpful to explain the simple crop case,
>>> for which you need to implement support to by adding s_selection on
>>> the sink pad TGT_CROP target.
>>
>> The scaler is kind of a dummy entity.
>> The problem is that different subdevices cannot be connected directly to
>> a v4l entity, because the ISC does cropping on the incoming frame.
>> The ISC has a limit on the total number of pixels per frame, thus it
>> will do a crop.
> 
> What is this limit related to ? I don't know the ISC internals, but is
> the limitation due to the overall image size, or maybe it's due to
> some line buffers being limited in the size they can transfer to
> memory ? Is it a limitation on the size of the image in pixels, or is
> it due to a limitation of the processing bandwidth on the input
> interface and thus depends on the actual size of the image in bytes ?

Limitation is both on line size and full image size. From my 
understanding, is that the internal SRAM is limited (8 Mpixels with a 
small safe buffer on top in the case of sama7g5 )
This SRAM could be used as 800000x10 for example, or 3200x2464 for 
another example. However, I am not sure if a real line of 800,000 pixels 
make sense, or if there is another internal mechanism in the ISC that 
stops it.
In any case, the ISC is cropping the incoming frame from aaaXbbb up to 
the maximum frame that it can handle

> 
>> So, if I allow e.g. an entity that sends 3280x2464 , when the ISC can
>> only handle 3264x2464 , then we have two choices:
>> 1/ crop it and output the 3264x2464 -> cannot, because userspace expects
>> 3280x2464, and the whole pipeline fails to configure, there is a
>> mismatch between /dev/video output and what the whole pipeline produces
> 
> I'm confused in first place. If the ISC cannot output anything larger
> than 3264x2464, then if userspace sets a 3280x2464 size on the ISC,
> this should be adjusted to 3264x2464.

yes, that is true. However, without an entity that says 'I am doing 
cropping', the media pipeline will fail, because previous entity will 
output 3280x2464 .
The conclusion to create a scaler entitity was done during my last year 
discussions on the IRC. I could not find a way to perform this cropping 
at the v4l entity side, and one reason is that the v4l entity does not 
support what I needed , or at least that was my understanding.
You claim that the v4l entity could perform the cropping in the same 
entity ?

Let's assume for a minute that it could do this. Even so, I would prefer 
to have a separate scaler entity to do this , for several reasons:
-> I would like to be able to crop the frame arbitrarily if I want to, 
and the scaler would allow me to do this easier
-> it would be more obvious that the frame is cropped by having this 
entity there
-> in fact some of the ISC versions really have a down scaler, that I 
have not implemented yet. So it would be useful to already have this in 
place to be able to scale down with it at a later time.

> 
> Or is the ISC limitation on the -input- side ?
> 
>> 2/ deny the link, and ask the subdevice to produce the 3264x2464 which
>> the ISC can handle at most -> cannot , because the sensor let's say can
>> *only* produce 3280x2464 and *any* other frame size returns an error.
> 
> buggy sensor I would say :)

I cannot tell this to the customers, and I cannot fail the whole 
pipeline because the sensor does not crop 16 pixels, when in fact I can 
do this very easily on the ISC side.

> 
>>
>> The only solution to make both worlds happy, is to have a dummy entity
>> called 'scaler' which in fact now it only performs a simple crop.
>> It accepts any frame size at input (hence the 10000x10000 which you saw
>> earlier), and outputs at most 3264x2464 the isc_max_height and
>> isc_max_width.
> 
> I have a maybe dumb question: can the cropping operation be modeled
> by applying a TGT_CROP rectangle (whose _BOUND size is 3280x2464) to
> the atmel_isc_common entity sink pad and avoid the scaler completely ?

I am not sure. This is what I wanted initially. But then I thought about 
the three reasons stated above for the use of the scaler entity, and 
discussed with folks on the IRC, and come up with the solution for the 
scaler entity

> 
>>
>> So to answer your question, the isc scaler is a software model for a
>> simple cropping, that would make media controller happy, and capture
>> software happy.
>>
>> Here it how it looks :
>>
>> Device topology
>> - entity 1: atmel_isc_scaler (2 pads, 2 links)
>>               type V4L2 subdev subtype Unknown flags 0
>>               device node name /dev/v4l-subdev0
>>           pad0: Sink
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb
>>                    crop.bounds:(0,0)/3264x2464
>>                    crop:(0,0)/3264x2464]
>>                   <- "csi2dc":1 [ENABLED,IMMUTABLE]
>>           pad1: Source
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb]
>>                   -> "atmel_isc_common":0 [ENABLED,IMMUTABLE]
>>
>> - entity 4: csi2dc (2 pads, 2 links)
>>               type V4L2 subdev subtype Unknown flags 0
>>               device node name /dev/v4l-subdev1
>>           pad0: Sink
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb]
>>                   <- "dw-csi.0":1 [ENABLED]
>>           pad1: Source
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb]
>>                   -> "atmel_isc_scaler":0 [ENABLED,IMMUTABLE]
>>
>> - entity 7: dw-csi.0 (2 pads, 2 links)
>>               type V4L2 subdev subtype Unknown flags 0
>>               device node name /dev/v4l-subdev2
>>           pad0: Sink
>>                   [fmt:SRGGB10_1X10/3280x2464]
>>                   <- "imx219 1-0010":0 [ENABLED]
>>           pad1: Source
>>                   [fmt:SRGGB10_1X10/3280x2464]
>>                   -> "csi2dc":0 [ENABLED]
>>
>> - entity 12: imx219 1-0010 (1 pad, 1 link)
>>                type V4L2 subdev subtype Sensor flags 0
>>                device node name /dev/v4l-subdev3
>>           pad0: Source
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb
>> xfer:srgb ycbcr:601 quantization:full-range
>>                    crop.bounds:(8,8)/3280x2464
>>                    crop:(8,8)/3280x2464]
>>                   -> "dw-csi.0":0 [ENABLED]
>>
>> - entity 24: atmel_isc_common (1 pad, 1 link)
>>                type Node subtype V4L flags 1
>>                device node name /dev/video0
>>           pad0: Sink
>>                   <- "atmel_isc_scaler":1 [ENABLED,IMMUTABLE]
>>
>>
>> Scaler does this one cute little thing :
>>
>>        pad0: Sink
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb
>>                    crop.bounds:(0,0)/3264x2464
>>                    crop:(0,0)/3264x2464]
>>                   <- "csi2dc":1 [ENABLED,IMMUTABLE]
>>           pad1: Source
>>                   [fmt:SRGGB10_1X10/3280x2464 field:none colorspace:srgb]
> 
> Shouldn't this be 3264x2464 as that's what the entity outputs after
> the cropping ? And shouldn't then be 3264x2464 the size output from
> the video device too ?

That's right.
I don't know why the source format for the scaler is still 3280x2464.
Maybe there is a bug on g_fmt for it.. have to check it.

Anyway, the video format is like this :

# v4l2-ctl --get-fmt-video
Format Video Capture:
         Width/Height      : 3264/2464
         Pixel Format      : 'RGBP' (16-bit RGB 5-6-5)
         Field             : None
         Bytes per Line    : 6528
         Size Image        : 16084992
         Colorspace        : sRGB
         Transfer Function : Default (maps to sRGB)
         YCbCr/HSV Encoding: Default (maps to ITU-R 601)
         Quantization      : Default (maps to Full Range)
         Flags             :
#

and initializing the pipeline looks fine from user perspective.
The scaler is in fact the solution to make this pipeline work with 
libcamera.
I found this cropping to be an issue in media controller when trying it 
with libcamera. Otherwise, the other user space apps which I was using 
never complained that anything was wrong
Libcamera simply refuses to acknowledge the pipeline if the video output 
is 3264x2464 but there is no entity that changes the format from 
3280x2464 down

> 
> 
>>                   -> "atmel_isc_common":0 [ENABLED,IMMUTABLE]
>>
>>
>> Which is what we needed.
>>
>>>
>>>> +
>>>> +     return 0;
>>>> +}
>>>> +
>>>> +static int isc_scaler_enum_mbus_code(struct v4l2_subdev *sd,
>>>> +                                  struct v4l2_subdev_state *sd_state,
>>>> +                                  struct v4l2_subdev_mbus_code_enum *code)
>>>> +{
>>>> +     struct isc_device *isc = container_of(sd, struct isc_device, scaler_sd);
>>>> +     int supported_index = 0;
>>>> +     int i;
>>>> +
>>>> +     for (i = 0; i < isc->formats_list_size; i++) {
>>>> +             if (!isc->formats_list[i].sd_support)
>>>> +                     continue;
>>>
>>> The sd_support flag still doesn't click in my head.
>>>
>>> Shouldn't the enumeration of available formats on the scaler do not
>>> depend on the sensor supproted formats ?
>>
>> You're right. I will have to check it again.
>>
>>>
>>>> +             if (supported_index == code->index) {
>>>> +                     code->code = isc->formats_list[i].mbus_code;
>>>> +                     return 0;
>>>> +             }
>>>> +             supported_index++;
>>>> +     }
>>>> +
>>>> +     return -EINVAL;
>>>> +}
>>>> +
>>>> +static int isc_scaler_g_sel(struct v4l2_subdev *sd,
>>>> +                         struct v4l2_subdev_state *sd_state,
>>>> +                         struct v4l2_subdev_selection *sel)
>>>> +{
>>>> +     struct isc_device *isc = container_of(sd, struct isc_device, scaler_sd);
>>>> +
>>>> +     if (sel->pad == ISC_SCALER_PAD_SOURCE)
>>>> +             return -EINVAL;
>>>> +
>>>> +     if (sel->target != V4L2_SEL_TGT_CROP_BOUNDS &&
>>>> +         sel->target != V4L2_SEL_TGT_CROP)
>>>> +             return -EINVAL;
>>>> +
>>>> +     sel->r.height = isc->max_height;
>>>> +     sel->r.width = isc->max_width;
>>>
>>> The CROP_BOUNDS should be set to the same size as the sink pad image format,
>>> as it represents the maximum valid crop rectangle.
>>>
>>> TGT_CROP should report the configured crop rectangle which can be
>>> intiialized to the same size as CROP_BOUNDS, if my understanding of
>>> the spec is correct
>>
>> So you would like to have this differentiated, and report the
>> CROP_BOUNDS to whatever is on the sink pad, and the TGT_CROP to what is
>> reported now, the maximum size of the ISC frame .
>> My understanding is correct ?
>>
> 
> I didn't know you have an HW limitation, so your _BOUNDS is not the
> input image size but rather 3264x2464 ( == max_width x max_height).
> 
> What I meant is that _BOUNDS should report the maximum rectangle size
> that can be applied to the _CROP target. In you case you have an HW
> limitation 3264x2464 and that's the largest rectangle you can apply.
So the CROP should be at 3264x2464
> TGT_CROP can be initialized to the same as _BOUND, but if you
> implement s_selection it should report what has been there applied.
and BOUND to actual frame size ?
> But as you don't implement s_selection yet, I think this is fine for
> now. Maybe a little comment ?

It could also be the case where e.g. the sensor is outputting 1920x1080, 
in this case the scaler would do nothing.
CROP is still 3264x2464 and BOUND in this case is 1920x1080 ?
If the sensor is outputting 1920x1080, this format comes directly from 
the sensor (the sensor is cropping it from 3280x2464 or not... it's the 
sensor's problem)
> 
> Also, is set->r zeroed by the framework before getting here ?
> Otherwise you should set r.left and r.top to 0

If these are redundant, no problem to remove them
> 
>>>
>>>> +
>>>> +     sel->r.left = 0;
>>>> +     sel->r.top = 0;
>>>> +
>>>> +     return 0;
>>>> +}
>>>> +
>>>> +static int isc_scaler_init_cfg(struct v4l2_subdev *sd,
>>>> +                            struct v4l2_subdev_state *sd_state)
>>>> +{
>>>> +     struct v4l2_mbus_framefmt *v4l2_try_fmt =
>>>> +             v4l2_subdev_get_try_format(sd, sd_state, 0);
>>>> +     struct isc_device *isc = container_of(sd, struct isc_device, scaler_sd);
>>>> +
>>>> +     *v4l2_try_fmt = isc->scaler_format;
>>>> +
>>>> +     return 0;
>>>> +}
>>>> +
>>>> +static const struct v4l2_subdev_pad_ops isc_scaler_pad_ops = {
>>>> +     .enum_mbus_code = isc_scaler_enum_mbus_code,
>>>> +     .set_fmt = isc_scaler_set_fmt,
>>>> +     .get_fmt = isc_scaler_get_fmt,
>>>> +     .get_selection = isc_scaler_g_sel,
>>>> +     .init_cfg = isc_scaler_init_cfg,
>>>
>>> .link_validate = v4l2_subdev_link_validate_default,
>>>
>>> To have the formats at the end of links that point to this entity
>>> validated (I think the framework already calls it if not set though,
>>> please check v4l2-subdev.c:v4l2_subdev_link_validate())
>>>
>>>> +};
>>>> +
>>>> +static const struct v4l2_subdev_ops xisc_scaler_subdev_ops = {
>>>> +     .pad = &isc_scaler_pad_ops,
>>>> +};
>>>> +
>>>> +int isc_scaler_init(struct isc_device *isc)
>>>> +{
>>>> +     int ret;
>>>> +
>>>> +     v4l2_subdev_init(&isc->scaler_sd, &xisc_scaler_subdev_ops);
>>>> +
>>>> +     isc->scaler_sd.owner = THIS_MODULE;
>>>> +     isc->scaler_sd.dev = isc->dev;
>>>> +     snprintf(isc->scaler_sd.name, sizeof(isc->scaler_sd.name),
>>>> +              "atmel_isc_scaler");
>>>
>>> I would drop 'atmel' for brevity, unless other entities have this
>>> prefix set already
>>
>> The v4l entity takes it's name from the module name, which is
>> atmel_isc_common, so I thought to keep the prefix
>>
> 
> Ack!
> 
>>>
>>>> +
>>>> +     isc->scaler_sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>>>> +     isc->scaler_sd.entity.function = MEDIA_ENT_F_PROC_VIDEO_SCALER;
>>>> +     isc->scaler_pads[ISC_SCALER_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>>>> +     isc->scaler_pads[ISC_SCALER_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
>>>> +
>>>> +     isc->scaler_format.height = isc->max_height;
>>>> +     isc->scaler_format.width = isc->max_width;
>>>> +     isc->scaler_format.code = isc->formats_list[0].mbus_code;
>>>> +     isc->scaler_format.colorspace = V4L2_COLORSPACE_SRGB;
>>>> +     isc->scaler_format.field = V4L2_FIELD_NONE;
>>>> +     isc->scaler_format.ycbcr_enc = V4L2_YCBCR_ENC_DEFAULT;
>>>> +     isc->scaler_format.quantization = V4L2_QUANTIZATION_DEFAULT;
>>>> +     isc->scaler_format.xfer_func = V4L2_XFER_FUNC_DEFAULT;
>>>> +
>>>> +     ret = media_entity_pads_init(&isc->scaler_sd.entity,
>>>> +                                  ISC_SCALER_PADS_NUM,
>>>> +                                  isc->scaler_pads);
>>>> +     if (ret < 0) {
>>>> +             dev_err(isc->dev, "scaler sd media entity init failed\n");
>>>> +             return ret;
>>>> +     }
>>>> +     ret = v4l2_device_register_subdev(&isc->v4l2_dev, &isc->scaler_sd);
>>>> +     if (ret < 0) {
>>>> +             dev_err(isc->dev, "scaler sd failed to register subdev\n");
>>>> +             return ret;
>>>> +     }
>>>> +
>>>> +     return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(isc_scaler_init);
>>>> +
>>>> +int isc_scaler_link(struct isc_device *isc)
>>>> +{
>>>> +     int ret;
>>>> +
>>>> +     ret = media_create_pad_link(&isc->current_subdev->sd->entity,
>>>> +                                 isc->remote_pad, &isc->scaler_sd.entity,
>>>> +                                 ISC_SCALER_PAD_SINK,
>>>> +                                 MEDIA_LNK_FL_ENABLED |
>>>> +                                 MEDIA_LNK_FL_IMMUTABLE);
>>>> +
>>>> +     if (ret < 0) {
>>>> +             v4l2_err(&isc->v4l2_dev,
>>>> +                      "Failed to create pad link: %s to %s\n",
>>>> +                      isc->current_subdev->sd->entity.name,
>>>> +                      isc->scaler_sd.entity.name);
>>>> +             return ret;
>>>> +     }
>>>> +
>>>> +     dev_dbg(isc->dev, "link with %s pad: %d\n",
>>>> +             isc->current_subdev->sd->name, isc->remote_pad);
>>>> +
>>>> +     ret = media_create_pad_link(&isc->scaler_sd.entity,
>>>> +                                 ISC_SCALER_PAD_SOURCE,
>>>> +                                 &isc->video_dev.entity, ISC_PAD_SINK,
>>>> +                                 MEDIA_LNK_FL_ENABLED |
>>>> +                                 MEDIA_LNK_FL_IMMUTABLE);
>>>> +
>>>> +     if (ret < 0) {
>>>> +             v4l2_err(&isc->v4l2_dev,
>>>> +                      "Failed to create pad link: %s to %s\n",
>>>> +                      isc->scaler_sd.entity.name,
>>>> +                      isc->video_dev.entity.name);
>>>> +             return ret;
>>>> +     }
>>>> +
>>>> +     dev_dbg(isc->dev, "link with %s pad: %d\n", isc->scaler_sd.name,
>>>> +             ISC_SCALER_PAD_SOURCE);
>>>> +
>>>> +     return ret;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(isc_scaler_link);
>>>
>>>   From the DT graph point of view, the ISC appears as a single block
>>> with an CSI-2 input port. It is then in charge of parsing the .dts and
>>> add to its notifier the image sensor remote subdevice.
>>
>> Actually it's only a parallel port.
>> And it can be connected either to a sensor directly or to the csi2dc
>> bridge. (the csi2dc bridge can be connected to a CSI-2 receiver)
>>
>>>
>>> When the sensor subdev registers and the ISC notifier completes, the scaler
>>> entity which was initialized at isc_probe() time is linked in between
>>> the ISC and the image sensor immutably.
>>
>> yes, because this cannot change at runtime, and usually, it can't change
>> without altering the board hardware. (at least this is what my
>> understanding of immutability is )
>>
>>>
>>> I think it is fine for now, but I wonder if you plan to plumb more
>>> components between the ISC video node and the sensor, if it's not
>>> worth changing the DT bindings and their parsing logic to separate the
>>> CSI-2 receiver from the ISC, whcih can create its media graph at probe
>>> time and have the CSI-2 receiver entity as downstream remote. I think
>>> I need to get to know the ISC better to really have an idea. For now,
>>> this seems ok to me, but please check with maintainers if this is fine
>>> with them.
>>
>> In the XISC case (sama7g5-isc), the csi2dc receiver is the subdev (so,
>> the remote subdev).
>> The ISC will register a scaler, and connect the subdev to this scaler
>> first, and then, the scaler to the isc itself (the v4l entity).
>>
>>>
>>>> +
>>>> diff --git a/drivers/media/platform/atmel/atmel-isc.h b/drivers/media/platform/atmel/atmel-isc.h
>>>> index 5fbf52a9080b..c9234c90ae58 100644
>>>> --- a/drivers/media/platform/atmel/atmel-isc.h
>>>> +++ b/drivers/media/platform/atmel/atmel-isc.h
>>>> @@ -183,6 +183,17 @@ struct isc_reg_offsets {
>>>>         u32 his_entry;
>>>>    };
>>>>
>>>> +enum isc_mc_pads {
>>>> +     ISC_PAD_SINK    = 0,
>>>> +     ISC_PADS_NUM    = 1,
>>>> +};
>>>> +
>>>> +enum isc_scaler_pads {
>>>> +     ISC_SCALER_PAD_SINK     = 0,
>>>> +     ISC_SCALER_PAD_SOURCE   = 1,
>>>> +     ISC_SCALER_PADS_NUM     = 2,
>>>> +};
>>>> +
>>>>    /*
>>>>     * struct isc_device - ISC device driver data/config struct
>>>>     * @regmap:          Register map
>>>> @@ -257,6 +268,12 @@ struct isc_reg_offsets {
>>>>     *                   be used as an input to the controller
>>>>     * @controller_formats_size: size of controller_formats array
>>>>     * @formats_list_size:       size of formats_list array
>>>> + * @pads:            media controller pads for isc video entity
>>>> + * @mdev:            media device that is registered by the isc
>>>> + * @remote_pad:              remote pad on the connected subdevice
>>>> + * @scaler_sd:               subdevice for the scaler that isc registers
>>>> + * @scaler_pads:     media controller pads for the scaler subdevice
>>>> + * @scaler_format:   current format for the scaler subdevice
>>>>     */
>>>>    struct isc_device {
>>>>         struct regmap           *regmap;
>>>> @@ -344,6 +361,19 @@ struct isc_device {
>>>>         struct isc_format               *formats_list;
>>>>         u32                             controller_formats_size;
>>>>         u32                             formats_list_size;
>>>> +
>>>> +     struct {
>>>> +             struct media_pad                pads[ISC_PADS_NUM];
>>>> +             struct media_device             mdev;
>>>> +
>>>> +             u32                             remote_pad;
>>>> +     };
>>>> +
>>>> +     struct {
>>>> +             struct v4l2_subdev              scaler_sd;
>>>> +             struct media_pad                scaler_pads[ISC_SCALER_PADS_NUM];
>>>> +             struct v4l2_mbus_framefmt       scaler_format;
>>
>> Here are the scaler stuff which I added, in the same bulk struct for the
>> whole isc device
>>
>>
>>>> +     };
>>>>    };
>>>>
>>>>    extern const struct regmap_config isc_regmap_config;
>>>> @@ -355,4 +385,11 @@ int isc_clk_init(struct isc_device *isc);
>>>>    void isc_subdev_cleanup(struct isc_device *isc);
>>>>    void isc_clk_cleanup(struct isc_device *isc);
>>>>
>>>> +int isc_scaler_link(struct isc_device *isc);
>>>> +int isc_scaler_init(struct isc_device *isc);
>>>> +int isc_mc_init(struct isc_device *isc, u32 ver);
>>>> +void isc_mc_cleanup(struct isc_device *isc);
>>>> +
>>>> +struct isc_format *isc_find_format_by_code(struct isc_device *isc,
>>>> +                                        unsigned int code, int *index);
>>>>    #endif
>>>> diff --git a/drivers/media/platform/atmel/atmel-sama5d2-isc.c b/drivers/media/platform/atmel/atmel-sama5d2-isc.c
>>>> index c5b9563e36cb..c244682ea22f 100644
>>>> --- a/drivers/media/platform/atmel/atmel-sama5d2-isc.c
>>>> +++ b/drivers/media/platform/atmel/atmel-sama5d2-isc.c
>>>> @@ -553,6 +553,12 @@ static int atmel_isc_probe(struct platform_device *pdev)
>>>>                         break;
>>>>         }
>>>>
>>>> +     regmap_read(isc->regmap, ISC_VERSION + isc->offsets.version, &ver);
>>>
>>> I am surprised you can read a register before runtime_pm is
>>> intialized!
>>>
>>
>> Actually I can read any register after the moment of starting the clock
>> on the hardware block.
> 
> Ah right then
> 
>> Maybe the starting and stopping of the clock needs to be moved to the
>> runtime_pm calls, but this is another story, not related to the media
>> controller.
> 
> It's fine, but maybe worth recording with a todo ?
> 
> Thanks
>    j
> 
>> I moved this line because I had to pass the version to the isc_mc_init call
>>
>>> Thanks
>>>      j
>>
>> Thanks for reviewing !
>> Eugen
>>>
>>>
>>>> +
>>>> +     ret = isc_mc_init(isc, ver);
>>>> +     if (ret < 0)
>>>> +             goto isc_probe_mc_init_err;
>>>> +
>>>>         pm_runtime_set_active(dev);
>>>>         pm_runtime_enable(dev);
>>>>         pm_request_idle(dev);
>>>> @@ -562,7 +568,7 @@ static int atmel_isc_probe(struct platform_device *pdev)
>>>>         ret = clk_prepare_enable(isc->ispck);
>>>>         if (ret) {
>>>>                 dev_err(dev, "failed to enable ispck: %d\n", ret);
>>>> -             goto cleanup_subdev;
>>>> +             goto isc_probe_mc_init_err;
>>>>         }
>>>>
>>>>         /* ispck should be greater or equal to hclock */
>>>> @@ -572,7 +578,6 @@ static int atmel_isc_probe(struct platform_device *pdev)
>>>>                 goto unprepare_clk;
>>>>         }
>>>>
>>>> -     regmap_read(isc->regmap, ISC_VERSION + isc->offsets.version, &ver);
>>>>         dev_info(dev, "Microchip ISC version %x\n", ver);
>>>>
>>>>         return 0;
>>>> @@ -580,6 +585,9 @@ static int atmel_isc_probe(struct platform_device *pdev)
>>>>    unprepare_clk:
>>>>         clk_disable_unprepare(isc->ispck);
>>>>
>>>> +isc_probe_mc_init_err:
>>>> +     isc_mc_cleanup(isc);
>>>> +
>>>>    cleanup_subdev:
>>>>         isc_subdev_cleanup(isc);
>>>>
>>>> @@ -600,6 +608,8 @@ static int atmel_isc_remove(struct platform_device *pdev)
>>>>
>>>>         pm_runtime_disable(&pdev->dev);
>>>>
>>>> +     isc_mc_cleanup(isc);
>>>> +
>>>>         isc_subdev_cleanup(isc);
>>>>
>>>>         v4l2_device_unregister(&isc->v4l2_dev);
>>>> diff --git a/drivers/media/platform/atmel/atmel-sama7g5-isc.c b/drivers/media/platform/atmel/atmel-sama7g5-isc.c
>>>> index 07a80b08bc54..9dc75eed0098 100644
>>>> --- a/drivers/media/platform/atmel/atmel-sama7g5-isc.c
>>>> +++ b/drivers/media/platform/atmel/atmel-sama7g5-isc.c
>>>> @@ -547,15 +547,23 @@ static int microchip_xisc_probe(struct platform_device *pdev)
>>>>                         break;
>>>>         }
>>>>
>>>> +     regmap_read(isc->regmap, ISC_VERSION + isc->offsets.version, &ver);
>>>> +
>>>> +     ret = isc_mc_init(isc, ver);
>>>> +     if (ret < 0)
>>>> +             goto isc_probe_mc_init_err;
>>>> +
>>>>         pm_runtime_set_active(dev);
>>>>         pm_runtime_enable(dev);
>>>>         pm_request_idle(dev);
>>>>
>>>> -     regmap_read(isc->regmap, ISC_VERSION + isc->offsets.version, &ver);
>>>>         dev_info(dev, "Microchip XISC version %x\n", ver);
>>>>
>>>>         return 0;
>>>>
>>>> +isc_probe_mc_init_err:
>>>> +     isc_mc_cleanup(isc);
>>>> +
>>>>    cleanup_subdev:
>>>>         isc_subdev_cleanup(isc);
>>>>
>>>> @@ -576,6 +584,8 @@ static int microchip_xisc_remove(struct platform_device *pdev)
>>>>
>>>>         pm_runtime_disable(&pdev->dev);
>>>>
>>>> +     isc_mc_cleanup(isc);
>>>> +
>>>>         isc_subdev_cleanup(isc);
>>>>
>>>>         v4l2_device_unregister(&isc->v4l2_dev);
>>>> --
>>>> 2.25.1
>>>>
>>
Jacopo Mondi Feb. 10, 2022, 6:43 p.m. UTC | #2
Hi Eugen

On Fri, Jan 21, 2022 at 03:14:12PM +0200, Eugen Hristev wrote:
> As a top MC video driver, the atmel-isc should not propagate the format to the
> subdevice.
> It should rather check at start_streaming() time if the subdev is properly
> configured with a compatible format.
> Removed the whole format finding logic, and reworked the format verification
> at start_streaming time, such that the ISC will return an error if the subdevice
> is not properly configured. To achieve this, media_pipeline_start
> is called and a link_validate callback is created to check the formats.
> With this being done, the module parameter 'sensor_preferred' makes no sense
> anymore. The ISC should not decide which format the sensor is using. The
> ISC should only cope with the situation and inform userspace if the streaming
> is possible in the current configuration.

This sounds right!

> The redesign of the format propagation has also risen the question of the
> enumfmt callback. If enumfmt is called with an mbus_code, the enumfmt handler
> should only return the formats that are supported for this mbus_code.
> To make it more easy to understand the formats, changed the report order
> to report first the native formats, and after that the formats that the ISC
> can convert to.
>
> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> ---
> Changes in v4:
> - moved validation code into link_validate and used media_pipeline_start
> - merged this patch with the enum_fmt patch which was previously in v3 of
> the series
>
> Changes in v3:
> - clamp to maximum resolution once the frame size from the subdev is found
>
>  drivers/media/platform/atmel/atmel-isc-base.c | 335 ++++++++++--------
>  .../media/platform/atmel/atmel-isc-scaler.c   |   5 +
>  drivers/media/platform/atmel/atmel-isc.h      |   3 +
>  3 files changed, 191 insertions(+), 152 deletions(-)
>
> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
> index f7a88399bd54..31c79313aadc 100644
> --- a/drivers/media/platform/atmel/atmel-isc-base.c
> +++ b/drivers/media/platform/atmel/atmel-isc-base.c
> @@ -36,11 +36,6 @@ static unsigned int debug;
>  module_param(debug, int, 0644);
>  MODULE_PARM_DESC(debug, "debug level (0-2)");
>
> -static unsigned int sensor_preferred = 1;
> -module_param(sensor_preferred, uint, 0644);
> -MODULE_PARM_DESC(sensor_preferred,
> -		 "Sensor is preferred to output the specified format (1-on 0-off), default 1");
> -
>  #define ISC_IS_FORMAT_RAW(mbus_code) \
>  	(((mbus_code) & 0xf000) == 0x3000)
>
> @@ -337,6 +332,10 @@ static int isc_start_streaming(struct vb2_queue *vq, unsigned int count)
>  	unsigned long flags;
>  	int ret;
>
> +	ret = media_pipeline_start(&isc->video_dev.entity, &isc->mpipe);
> +	if (ret)
> +		goto err_pipeline_start;
> +
>  	/* Enable stream on the sub device */
>  	ret = v4l2_subdev_call(isc->current_subdev->sd, video, s_stream, 1);
>  	if (ret && ret != -ENOIOCTLCMD) {
> @@ -384,6 +383,9 @@ static int isc_start_streaming(struct vb2_queue *vq, unsigned int count)
>  	v4l2_subdev_call(isc->current_subdev->sd, video, s_stream, 0);
>
>  err_start_stream:
> +	media_pipeline_stop(&isc->video_dev.entity);
> +
> +err_pipeline_start:
>  	spin_lock_irqsave(&isc->dma_queue_lock, flags);
>  	list_for_each_entry(buf, &isc->dma_queue, list)
>  		vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_QUEUED);
> @@ -420,6 +422,9 @@ static void isc_stop_streaming(struct vb2_queue *vq)
>  	if (ret && ret != -ENOIOCTLCMD)
>  		v4l2_err(&isc->v4l2_dev, "stream off failed in subdev\n");
>
> +	/* Stop media pipeline */
> +	media_pipeline_stop(&isc->video_dev.entity);
> +
>  	/* Release all active buffers */
>  	spin_lock_irqsave(&isc->dma_queue_lock, flags);
>  	if (unlikely(isc->cur_frm)) {
> @@ -496,21 +501,56 @@ static int isc_enum_fmt_vid_cap(struct file *file, void *priv,
>  	u32 index = f->index;
>  	u32 i, supported_index;
>
> -	if (index < isc->controller_formats_size) {
> -		f->pixelformat = isc->controller_formats[index].fourcc;
> -		return 0;
> +	supported_index = 0;
> +
> +	for (i = 0; i < isc->formats_list_size; i++) {
> +		if (!isc->formats_list[i].sd_support)
> +			continue;

Sorry to ask again about sd_support, but if the ISC formats
enumeration is not constrained to a specific mbus_code, shouldn't all
the formats be enumerated regardless if they're supported from the
sensor or not ?

> +		/*
> +		 * If specific mbus_code is requested, provide only
> +		 * supported formats with this mbus code
> +		 */
> +		if (f->mbus_code && f->mbus_code !=
> +		    isc->formats_list[i].mbus_code)

nit: for clarity
		if (f->mbus_code &&
                    f->mbus_code != isc->formats_list[i].mbus_code)

> +			continue;
> +		if (supported_index == index) {
> +			f->pixelformat = isc->formats_list[i].fourcc;
> +			return 0;
> +		}
> +		supported_index++;
>  	}
>
> -	index -= isc->controller_formats_size;
> +	/*
> +	 * If the sensor does not support this mbus_code whatsoever,
> +	 * there is no reason to advertise any of our output formats
> +	 */
> +	if (supported_index == 0)
> +		return -EINVAL;
>
> +	/*
> +	 * If the sensor uses a format that is not raw, then we cannot
> +	 * convert it to any of the formats that we usually can with a
> +	 * RAW sensor. Thus, do not advertise them.
> +	 */
> +	if (isc->config.sd_format &&
> +	    !ISC_IS_FORMAT_RAW(isc->config.sd_format->mbus_code))
> +		return -EINVAL;
> +
> +	/*
> +	 * Iterate again through the formats that we can convert to.
> +	 * However, to avoid duplicates, skip the formats that
> +	 * the sensor already supports directly
> +	 */
> +	index -= supported_index;
>  	supported_index = 0;
>
> -	for (i = 0; i < isc->formats_list_size; i++) {
> -		if (!ISC_IS_FORMAT_RAW(isc->formats_list[i].mbus_code) ||
> -		    !isc->formats_list[i].sd_support)
> +	for (i = 0; i < isc->controller_formats_size; i++) {
> +		/* if this format is already supported by sensor, skip it */
> +		if (find_format_by_fourcc(isc, isc->controller_formats[i].fourcc))
>  			continue;
>  		if (supported_index == index) {
> -			f->pixelformat = isc->formats_list[i].fourcc;
> +			f->pixelformat =
> +				isc->controller_formats[i].fourcc;

I trust this last part to work correctly, as it's not 100% clear to me :)

>  			return 0;
>  		}
>  		supported_index++;
> @@ -581,20 +621,30 @@ static int isc_try_validate_formats(struct isc_device *isc)
>  		break;
>  	default:
>  	/* any other different formats are not supported */
> +		v4l2_err(&isc->v4l2_dev, "Requested unsupported format.\n");
>  		ret = -EINVAL;
>  	}
>  	v4l2_dbg(1, debug, &isc->v4l2_dev,
>  		 "Format validation, requested rgb=%u, yuv=%u, grey=%u, bayer=%u\n",
>  		 rgb, yuv, grey, bayer);
>
> -	/* we cannot output RAW if we do not receive RAW */
> -	if ((bayer) && !ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code))
> +	if ((bayer) &&

just 'bayer' ?

> +	    !ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code)) {
> +		v4l2_err(&isc->v4l2_dev, "Cannot output RAW if we do not receive RAW.\n");
>  		return -EINVAL;
> +	}
>
> -	/* we cannot output GREY if we do not receive RAW/GREY */
>  	if (grey && !ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code) &&
> -	    !ISC_IS_FORMAT_GREY(isc->try_config.sd_format->mbus_code))
> +	    !ISC_IS_FORMAT_GREY(isc->try_config.sd_format->mbus_code)) {
> +		v4l2_err(&isc->v4l2_dev, "Cannot output GREY if we do not receive RAW/GREY.\n");
> +		return -EINVAL;
> +	}
> +
> +	if ((rgb || bayer || yuv) &&
> +	    ISC_IS_FORMAT_GREY(isc->try_config.sd_format->mbus_code)) {
> +		v4l2_err(&isc->v4l2_dev, "Cannot convert GREY to another format.\n");
>  		return -EINVAL;
> +	}
>
>  	return ret;
>  }
> @@ -822,7 +872,7 @@ static void isc_try_fse(struct isc_device *isc,
>  	 * If we do not know yet which format the subdev is using, we cannot
>  	 * do anything.
>  	 */
> -	if (!isc->try_config.sd_format)
> +	if (!isc->config.sd_format)
>  		return;
>
>  	fse.code = isc->try_config.sd_format->mbus_code;
> @@ -843,180 +893,141 @@ static void isc_try_fse(struct isc_device *isc,
>  	}
>  }
>
> -static int isc_try_fmt(struct isc_device *isc, struct v4l2_format *f,
> -			u32 *code)
> +static int isc_try_fmt(struct isc_device *isc, struct v4l2_format *f)
>  {
> -	int i;
> -	struct isc_format *sd_fmt = NULL, *direct_fmt = NULL;
>  	struct v4l2_pix_format *pixfmt = &f->fmt.pix;
> -	struct v4l2_subdev_pad_config pad_cfg = {};
> -	struct v4l2_subdev_state pad_state = {
> -		.pads = &pad_cfg
> -		};
> -	struct v4l2_subdev_format format = {
> -		.which = V4L2_SUBDEV_FORMAT_TRY,
> -	};
> -	u32 mbus_code;
> -	int ret;
> -	bool rlp_dma_direct_dump = false;
> +	unsigned int i;
>
>  	if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE)
>  		return -EINVAL;
>
> -	/* Step 1: find a RAW format that is supported */
> -	for (i = 0; i < isc->num_user_formats; i++) {
> -		if (ISC_IS_FORMAT_RAW(isc->user_formats[i]->mbus_code)) {
> -			sd_fmt = isc->user_formats[i];
> +	isc->try_config.fourcc = isc->user_formats[0]->fourcc;
> +
> +	/* find if the format requested is supported */
> +	for (i = 0; i < isc->controller_formats_size; i++)
> +		if (isc->controller_formats[i].fourcc == pixfmt->pixelformat) {
> +			isc->try_config.fourcc = pixfmt->pixelformat;
>  			break;
>  		}
> -	}
> -	/* Step 2: We can continue with this RAW format, or we can look
> -	 * for better: maybe sensor supports directly what we need.
> -	 */
> -	direct_fmt = find_format_by_fourcc(isc, pixfmt->pixelformat);
> -
> -	/* Step 3: We have both. We decide given the module parameter which
> -	 * one to use.
> -	 */
> -	if (direct_fmt && sd_fmt && sensor_preferred)
> -		sd_fmt = direct_fmt;
> -
> -	/* Step 4: we do not have RAW but we have a direct format. Use it. */
> -	if (direct_fmt && !sd_fmt)
> -		sd_fmt = direct_fmt;
> -
> -	/* Step 5: if we are using a direct format, we need to package
> -	 * everything as 8 bit data and just dump it
> -	 */
> -	if (sd_fmt == direct_fmt)
> -		rlp_dma_direct_dump = true;
> -
> -	/* Step 6: We have no format. This can happen if the userspace
> -	 * requests some weird/invalid format.
> -	 * In this case, default to whatever we have
> -	 */
> -	if (!sd_fmt && !direct_fmt) {
> -		sd_fmt = isc->user_formats[isc->num_user_formats - 1];
> -		v4l2_dbg(1, debug, &isc->v4l2_dev,
> -			 "Sensor not supporting %.4s, using %.4s\n",
> -			 (char *)&pixfmt->pixelformat, (char *)&sd_fmt->fourcc);
> -	}
> -
> -	if (!sd_fmt) {
> -		ret = -EINVAL;
> -		goto isc_try_fmt_err;
> -	}
> -
> -	/* Step 7: Print out what we decided for debugging */
> -	v4l2_dbg(1, debug, &isc->v4l2_dev,
> -		 "Preferring to have sensor using format %.4s\n",
> -		 (char *)&sd_fmt->fourcc);
> -
> -	/* Step 8: at this moment we decided which format the subdev will use */
> -	isc->try_config.sd_format = sd_fmt;
> -
> -	/* Limit to Atmel ISC hardware capabilities */
> -	if (pixfmt->width > isc->max_width)
> -		pixfmt->width = isc->max_width;
> -	if (pixfmt->height > isc->max_height)
> -		pixfmt->height = isc->max_height;
> -
> -	/*
> -	 * The mbus format is the one the subdev outputs.
> -	 * The pixels will be transferred in this format Sensor -> ISC
> -	 */
> -	mbus_code = sd_fmt->mbus_code;
> -
> -	/*
> -	 * Validate formats. If the required format is not OK, default to raw.
> -	 */
> -
> -	isc->try_config.fourcc = pixfmt->pixelformat;
> -
> -	if (isc_try_validate_formats(isc)) {
> -		pixfmt->pixelformat = isc->try_config.fourcc = sd_fmt->fourcc;
> -		/* Re-try to validate the new format */
> -		ret = isc_try_validate_formats(isc);
> -		if (ret)
> -			goto isc_try_fmt_err;
> -	}
> -
> -	ret = isc_try_configure_rlp_dma(isc, rlp_dma_direct_dump);
> -	if (ret)
> -		goto isc_try_fmt_err;
> -
> -	ret = isc_try_configure_pipeline(isc);
> -	if (ret)
> -		goto isc_try_fmt_err;
>
> -	/* Obtain frame sizes if possible to have crop requirements ready */
> -	isc_try_fse(isc, &pad_state);
> -
> -	v4l2_fill_mbus_format(&format.format, pixfmt, mbus_code);
> -	ret = v4l2_subdev_call(isc->current_subdev->sd, pad, set_fmt,
> -			       &pad_state, &format);
> -	if (ret < 0)
> -		goto isc_try_fmt_subdev_err;
> +	/* If we did not find the requested format, we will fallback here */
> +	pixfmt->pixelformat = isc->try_config.fourcc;
> +	pixfmt->colorspace = V4L2_COLORSPACE_SRGB;
> +	pixfmt->field = V4L2_FIELD_NONE;
>
> -	v4l2_fill_pix_format(pixfmt, &format.format);
> +	isc_try_configure_rlp_dma(isc, false);
>
>  	/* Limit to Atmel ISC hardware capabilities */
> -	if (pixfmt->width > isc->max_width)
> -		pixfmt->width = isc->max_width;
> -	if (pixfmt->height > isc->max_height)
> -		pixfmt->height = isc->max_height;
> +	v4l_bound_align_image(&pixfmt->width, 16, isc->max_width, 0,
> +			      &pixfmt->height, 16, isc->max_height, 0, 0);
>
>  	pixfmt->field = V4L2_FIELD_NONE;
>  	pixfmt->bytesperline = (pixfmt->width * isc->try_config.bpp_v4l2) >> 3;
>  	pixfmt->sizeimage = ((pixfmt->width * isc->try_config.bpp) >> 3) *
>  			     pixfmt->height;

Seems pixfmt->field is set twice.

Could you move the assignment of all pixfmt to a single block ?

>
> -	if (code)
> -		*code = mbus_code;
> +	isc->try_fmt = *f;
>
>  	return 0;
> +}
>
> -isc_try_fmt_err:
> -	v4l2_err(&isc->v4l2_dev, "Could not find any possible format for a working pipeline\n");
> -isc_try_fmt_subdev_err:
> -	memset(&isc->try_config, 0, sizeof(isc->try_config));
> +static int isc_set_fmt(struct isc_device *isc, struct v4l2_format *f)
> +{
> +	isc_try_fmt(isc, f);
>
> -	return ret;
> +	/* make the try configuration active */
> +	isc->config = isc->try_config;
> +	isc->fmt = isc->try_fmt;
> +
> +	v4l2_dbg(1, debug, &isc->v4l2_dev, "ISC set_fmt to %.4s @%dx%d\n",
> +		 (char *)&f->fmt.pix.pixelformat,
> +		 f->fmt.pix.width, f->fmt.pix.height);
> +
> +	return 0;
>  }
>
> -static int isc_set_fmt(struct isc_device *isc, struct v4l2_format *f)
> +static int isc_validate(struct isc_device *isc)
>  {
> +	int ret;
> +	int i;
> +	struct isc_format *sd_fmt = NULL;
> +	struct v4l2_pix_format *pixfmt = &isc->fmt.fmt.pix;
>  	struct v4l2_subdev_format format = {
>  		.which = V4L2_SUBDEV_FORMAT_ACTIVE,
> +		.pad = isc->remote_pad,
> +	};
> +	struct v4l2_subdev_pad_config pad_cfg = {};
> +	struct v4l2_subdev_state pad_state = {
> +		.pads = &pad_cfg,
>  	};
> -	u32 mbus_code = 0;
> -	int ret;
>
> -	ret = isc_try_fmt(isc, f, &mbus_code);
> +	/* Get current format from subdev */
> +	ret = v4l2_subdev_call(isc->current_subdev->sd, pad, get_fmt, NULL,
> +			       &format);
>  	if (ret)
>  		return ret;
>
> -	v4l2_fill_mbus_format(&format.format, &f->fmt.pix, mbus_code);
> -	ret = v4l2_subdev_call(isc->current_subdev->sd, pad,
> -			       set_fmt, NULL, &format);
> -	if (ret < 0)
> -		return ret;
> +	/* Identify the subdev's format configuration */
> +	for (i = 0; i < isc->num_user_formats; i++)
> +		if (isc->user_formats[i]->mbus_code == format.format.code) {
> +			sd_fmt = isc->user_formats[i];
> +			break;
> +		}
> +
> +	/* Check if the format is not supported */
> +	if (!sd_fmt) {
> +		v4l2_err(&isc->v4l2_dev,
> +			 "Current subdevice is streaming a media bus code that is not supported 0x%x\n",
> +			 format.format.code);
> +		return -EPIPE;
> +	}
> +
> +	/* At this moment we know which format the subdev will use */
> +	isc->try_config.sd_format = sd_fmt;
> +
> +	/* If the sensor is not RAW, we can only do a direct dump */
> +	if (!ISC_IS_FORMAT_RAW(isc->try_config.sd_format->mbus_code))
> +		isc_try_configure_rlp_dma(isc, true);
>
>  	/* Limit to Atmel ISC hardware capabilities */
> -	if (f->fmt.pix.width > isc->max_width)
> -		f->fmt.pix.width = isc->max_width;
> -	if (f->fmt.pix.height > isc->max_height)
> -		f->fmt.pix.height = isc->max_height;
> +	v4l_bound_align_image(&format.format.width, 16, isc->max_width, 0,
> +			      &format.format.height, 16, isc->max_height, 0, 0);
> +
> +	/* Check if the frame size is the same. Otherwise we may overflow */
> +	if (pixfmt->height != format.format.height ||
> +	    pixfmt->width != format.format.width) {
> +		v4l2_err(&isc->v4l2_dev,
> +			 "ISC not configured with the proper frame size: %dx%d\n",
> +			 format.format.width, format.format.height);
> +		return -EPIPE;
> +	}
>
> -	isc->fmt = *f;
> +	v4l2_dbg(1, debug, &isc->v4l2_dev,
> +		 "Identified subdev using format %.4s with %dx%d %d bpp\n",
> +		 (char *)&sd_fmt->fourcc, pixfmt->width, pixfmt->height,
> +		 isc->try_config.bpp);
>
> +	/* Reset and restart AWB if the subdevice changed the format */
>  	if (isc->try_config.sd_format && isc->config.sd_format &&
>  	    isc->try_config.sd_format != isc->config.sd_format) {
>  		isc->ctrls.hist_stat = HIST_INIT;
>  		isc_reset_awb_ctrls(isc);
>  		isc_update_v4l2_ctrls(isc);
>  	}
> -	/* make the try configuration active */
> +
> +	/* Validate formats */
> +	ret = isc_try_validate_formats(isc);
> +	if (ret)
> +		return ret;
> +
> +	/* Obtain frame sizes if possible to have crop requirements ready */
> +	isc_try_fse(isc, &pad_state);
> +
> +	/* Configure ISC pipeline for the config */
> +	ret = isc_try_configure_pipeline(isc);
> +	if (ret)
> +		return ret;
> +
>  	isc->config = isc->try_config;
>
>  	v4l2_dbg(1, debug, &isc->v4l2_dev, "New ISC configuration in place\n");
> @@ -1040,7 +1051,7 @@ static int isc_try_fmt_vid_cap(struct file *file, void *priv,
>  {
>  	struct isc_device *isc = video_drvdata(file);
>
> -	return isc_try_fmt(isc, f, NULL);
> +	return isc_try_fmt(isc, f);
>  }
>
>  static int isc_enum_input(struct file *file, void *priv,
> @@ -1841,7 +1852,7 @@ static int isc_set_default_fmt(struct isc_device *isc)
>  	};
>  	int ret;
>
> -	ret = isc_try_fmt(isc, &f, NULL);
> +	ret = isc_try_fmt(isc, &f);
>  	if (ret)
>  		return ret;
>
> @@ -2015,6 +2026,24 @@ int isc_pipeline_init(struct isc_device *isc)
>  }
>  EXPORT_SYMBOL_GPL(isc_pipeline_init);
>
> +int isc_link_validate(struct media_link *link)
> +{
> +	struct video_device *vdev =
> +		media_entity_to_video_device(link->sink->entity);
> +	struct isc_device *isc = video_get_drvdata(vdev);
> +	int ret;
> +
> +	ret = v4l2_subdev_link_validate(link);
> +	if (ret)
> +		return ret;

Doesn't v4l2_subdev_link_validate() call
v4l2_subdev_link_validate_default() if you don't define a .link_validate()
pad operation ? v4l2_subdev_link_validate_default() compares format
and sizes of both ends to the links and want them to be identical,
something that defeat the purpose of your custom isc_validate() ?

Thanks
  j

> +
> +	return isc_validate(isc);
> +}
> +
> +static const struct media_entity_operations isc_entity_operations = {
> +	.link_validate = isc_link_validate,
> +};
> +
};
>  int isc_mc_init(struct isc_device *isc, u32 ver)
>  {
>  	const struct of_device_id *match;
> @@ -2022,6 +2051,8 @@ int isc_mc_init(struct isc_device *isc, u32 ver)
>
>  	isc->video_dev.entity.function = MEDIA_ENT_F_IO_V4L;
>  	isc->video_dev.entity.flags = MEDIA_ENT_FL_DEFAULT;
> +	isc->video_dev.entity.ops = &isc_entity_operations;
> +
>  	isc->pads[ISC_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>
>  	ret = media_entity_pads_init(&isc->video_dev.entity, ISC_PADS_NUM,
> diff --git a/drivers/media/platform/atmel/atmel-isc-scaler.c b/drivers/media/platform/atmel/atmel-isc-scaler.c
> index ec95c9665883..93375a61aea6 100644
> --- a/drivers/media/platform/atmel/atmel-isc-scaler.c
> +++ b/drivers/media/platform/atmel/atmel-isc-scaler.c
> @@ -155,6 +155,10 @@ static const struct v4l2_subdev_pad_ops isc_scaler_pad_ops = {
>  	.init_cfg = isc_scaler_init_cfg,
>  };
>
> +static const struct media_entity_operations isc_scaler_entity_ops = {
> +	.link_validate = v4l2_subdev_link_validate,
> +};
> +
>  static const struct v4l2_subdev_ops xisc_scaler_subdev_ops = {
>  	.pad = &isc_scaler_pad_ops,
>  };
> @@ -172,6 +176,7 @@ int isc_scaler_init(struct isc_device *isc)
>
>  	isc->scaler_sd.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
>  	isc->scaler_sd.entity.function = MEDIA_ENT_F_PROC_VIDEO_SCALER;
> +	isc->scaler_sd.entity.ops = &isc_scaler_entity_ops;
>  	isc->scaler_pads[ISC_SCALER_PAD_SINK].flags = MEDIA_PAD_FL_SINK;
>  	isc->scaler_pads[ISC_SCALER_PAD_SOURCE].flags = MEDIA_PAD_FL_SOURCE;
>
> diff --git a/drivers/media/platform/atmel/atmel-isc.h b/drivers/media/platform/atmel/atmel-isc.h
> index 04ea5e340808..e36cf9d3942a 100644
> --- a/drivers/media/platform/atmel/atmel-isc.h
> +++ b/drivers/media/platform/atmel/atmel-isc.h
> @@ -270,6 +270,7 @@ enum isc_scaler_pads {
>   * @formats_list_size:	size of formats_list array
>   * @pads:		media controller pads for isc video entity
>   * @mdev:		media device that is registered by the isc
> + * @mpipe:		media device pipeline used by the isc
>   * @remote_pad:		remote pad on the connected subdevice
>   * @scaler_sd:		subdevice for the scaler that isc registers
>   * @scaler_pads:	media controller pads for the scaler subdevice
> @@ -295,6 +296,7 @@ struct isc_device {
>  	struct completion	comp;
>
>  	struct v4l2_format	fmt;
> +	struct v4l2_format	try_fmt;
>  	struct isc_format	**user_formats;
>  	unsigned int		num_user_formats;
>
> @@ -366,6 +368,7 @@ struct isc_device {
>  	struct {
>  		struct media_pad		pads[ISC_PADS_NUM];
>  		struct media_device		mdev;
> +		struct media_pipeline		mpipe;
>
>  		u32				remote_pad;
>  	};
> --
> 2.25.1
>