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Date:   Fri, 29 Apr 2022 13:07:07 +0300
From:   Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To:     Jacopo Mondi <jacopo@jmondi.org>
Cc:     Hans Verkuil <hverkuil@xs4all.nl>, Eugen.Hristev@microchip.com,
        linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Claudiu.Beznea@microchip.com, robh+dt@kernel.org,
        Nicolas.Ferre@microchip.com
Subject: Re: [PATCH v9 08/13] media: atmel: atmel-isc: change format
 propagation to subdev into only verification
Message-ID: <Ymu4ywjEvX5HbE/W@pendragon.ideasonboard.com>
References: <20220310095202.2701399-1-eugen.hristev@microchip.com>
 <20220310095202.2701399-9-eugen.hristev@microchip.com>
 <39f541ec-313f-fe15-b93f-dd78469b2366@xs4all.nl>
 <b6630c65-0720-3633-d5ed-aadf4716f206@microchip.com>
 <dabbff36-a10c-0a8a-94e8-ce7c2d896403@xs4all.nl>
 <20220429095848.ec4xnul6tin6n7sf@uno.localdomain>
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In-Reply-To: <20220429095848.ec4xnul6tin6n7sf@uno.localdomain>
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On Fri, Apr 29, 2022 at 11:58:48AM +0200, Jacopo Mondi wrote:
> On Fri, Apr 29, 2022 at 10:43:09AM +0200, Hans Verkuil wrote:
> > On 29/04/2022 10:28, Eugen.Hristev@microchip.com wrote:
> > > On 4/29/22 11:17 AM, Hans Verkuil wrote:
> > >> On 10/03/2022 10:51, 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.
> > >>> 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.
> > >>> Otherwise, the enumfmt will report all the formats that the ISC could output.
> > >>> With this rework, the dynamic list of user formats is removed. It makes no
> > >>> more sense to identify at complete time which formats the sensor could emit,
> > >>> and add those into a separate dynamic list.
> > >>> The ISC will start with a simple preconfigured default format, and at
> > >>> link validate time, decide whether it can use the format that is configured
> > >>> on the sink or not.
> > >>>
> > >>> Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com>
> > >>> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
> > >>> ---
> > >>> Changes in v9:
> > >>> - isc_link_validate now static
> > >>>
> > >>> Changes in v7:
> > >>> - minor typos as suggested by Jacopo
> > >>> - small changes, reduce some indentation, modified an index, as suggested by
> > >>> Jacopo
> > >>>
> > >>> Changes in v6:
> > >>> - reworked a bit enum_fmt as suggested by Jacopo
> > >>>
> > >>> Changes in v5:
> > >>> - removed user_formats dynamic list as it is now pointless
> > >>> - greatly simplified the enum_fmt function
> > >>> - removed some init code that was useless now
> > >>>
> > >>> 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 | 412 ++++++++----------
> > >>>   .../media/platform/atmel/atmel-isc-scaler.c   |   5 +
> > >>>   drivers/media/platform/atmel/atmel-isc.h      |  13 +-
> > >>>   .../media/platform/atmel/atmel-sama5d2-isc.c  |  20 +
> > >>>   .../media/platform/atmel/atmel-sama7g5-isc.c  |  20 +
> > >>>   5 files changed, 236 insertions(+), 234 deletions(-)
> > >>>
> > >>> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
> > >>> index ee1dda6707a0..fe2c0af58060 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);
> > >>
> > >> The pipeline validation is done in start_streaming, but I don't think that
> > >> is the best place: if STREAMON is called before buffers are queued, then
> > >> an invalid pipeline isn't discovered until enough buffers are queued to
> > >> kick off start_streaming.
> > >>
> > >> Drivers like vsp1, omap3isp and the samsung drivers all do this in streamon().
> > >>
> > >> I think that is the correct time to do this.
> > >
> > > Hello Hans,
> > >
> > > Initially (v2, v3) I had this in streamon(). The problem that I faced at
> > > that time was that streamoff was never called, so I could not call
> > > media_pipeline_stop(). Then Jacopo told me to move it to start_streaming
> > > (see change log for v4) , and I did not face any more problems.
> 
> Yes indeed, seems I suggested to use media_pipeline_handler in a
> comment on your v3
> 
> "at s_stream time your top driver calls media_pipeline_start()"
> 
> sorry about that, I should have looked around a bit more carefully and
> notice most drivers do so at vb2 streamon
> 
> However I don't see media_pipeline_start being called at all in v3 of
> the patch
> 
> > It's a mess. Looking at some drivers I see that omap3isp calls media_pipeline_stop
> > in streamoff (so will have the same problem as you described if VIDIOC_STREAMOFF
> > isn't called), exynos4-is does the same, but it also checks the streaming state in
> > the release() fop callback, so that would fix this problem. And vimc does this
> > in stop_streaming.
> >
> > I'm in favor of fixing this in vb2, that framework knows exactly when this needs
> > to be called.
> 
> Are you suggesting to have vb2 to call media_pipeline_start() or is it
> more complex than this ?

I think Hans meant adding a .validate() operation to vb2.

vb2 is already quite complex, I don't think adding more features is a
good idea. I'd rather have vb2 focus on buffer management only
(.start_streaming() and .stop_streaming() shouldn't have been in there
in my opinion), and handle validation in the .streamon() handler. I'd
expect most drivers that deal with media pipelines to do more work in
.streamon() anyway.

> > I'd like to know what others think.
> >
> > >> Laurent, Jacopo, do you agree with that?
> > >>
> > >> I notice that quite a few other drivers do this in start_streaming as well,
> > >> but I think it just weird that a QBUF can return EPIPE while STREAMON might
> > >> succeed.
> > >>
> > >> Perhaps we need an optional vb2 validate() callback that is called by
> > >> vb2_core_streamon() to validate the pipeline before streaming. That makes
> > >> it easier to implement these checks rather than having to implement your
> > >> own streamon ioctl.
> > >>
> > >>> +     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) {
> > >>> @@ -385,6 +384,9 @@ 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);
> > >>> @@ -423,6 +425,9 @@ 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)) {
> > >>> @@ -453,22 +458,6 @@ static void isc_buffer_queue(struct vb2_buffer *vb)
> > >>>        spin_unlock_irqrestore(&isc->dma_queue_lock, flags);
> > >>>   }
> > >>>
> > >>> -static struct isc_format *find_format_by_fourcc(struct isc_device *isc,
> > >>> -                                              unsigned int fourcc)
> > >>> -{
> > >>> -     unsigned int num_formats = isc->num_user_formats;
> > >>> -     struct isc_format *fmt;
> > >>> -     unsigned int i;
> > >>> -
> > >>> -     for (i = 0; i < num_formats; i++) {
> > >>> -             fmt = isc->user_formats[i];
> > >>> -             if (fmt->fourcc == fourcc)
> > >>> -                     return fmt;
> > >>> -     }
> > >>> -
> > >>> -     return NULL;
> > >>> -}
> > >>> -
> > >>>   static const struct vb2_ops isc_vb2_ops = {
> > >>>        .queue_setup            = isc_queue_setup,
> > >>>        .wait_prepare           = vb2_ops_wait_prepare,
> > >>> @@ -497,23 +486,57 @@ static int isc_enum_fmt_vid_cap(struct file *file, void *priv,
> > >>>   {
> > >>>        struct isc_device *isc = video_drvdata(file);
> > >>>        u32 index = f->index;
> > >>> -     u32 i, supported_index;
> > >>> +     u32 i, supported_index = 0;
> > >>> +     struct isc_format *fmt;
> > >>> +
> > >>> +     /*
> > >>> +      * If we are not asked a specific mbus_code, we have to report all
> > >>> +      * the formats that we can output.
> > >>> +      */
> > >>> +     if (!f->mbus_code) {
> > >>> +             if (index >= isc->controller_formats_size)
> > >>> +                     return -EINVAL;
> > >>>
> > >>> -     if (index < isc->controller_formats_size) {
> > >>>                f->pixelformat = isc->controller_formats[index].fourcc;
> > >>> +
> > >>> +             return 0;
> > >>> +     }
> > >>> +
> > >>> +     /*
> > >>> +      * If a specific mbus_code is requested, check if we support
> > >>> +      * this mbus_code as input for the ISC.
> > >>> +      * If it's supported, then we report the corresponding pixelformat
> > >>> +      * as first possible option for the ISC.
> > >>> +      * E.g. mbus MEDIA_BUS_FMT_YUYV8_2X8 and report
> > >>> +      * 'YUYV' (YUYV 4:2:2)
> > >>> +      */
> > >>> +     fmt = isc_find_format_by_code(isc, f->mbus_code, &i);
> > >>> +     if (!fmt)
> > >>> +             return -EINVAL;
> > >>> +
> > >>> +     if (!index) {
> > >>> +             f->pixelformat = fmt->fourcc;
> > >>> +
> > >>>                return 0;
> > >>>        }
> > >>>
> > >>> -     index -= isc->controller_formats_size;
> > >>> +     supported_index++;
> > >>>
> > >>> -     supported_index = 0;
> > >>> +     /* If the index is not raw, we don't have anymore formats to report */
> > >>> +     if (!ISC_IS_FORMAT_RAW(f->mbus_code))
> > >>> +             return -EINVAL;
> > >>>
> > >>> -     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)
> > >>> +     /*
> > >>> +      * We are asked for a specific mbus code, which is raw.
> > >>> +      * We have to search through the formats we can convert to.
> > >>> +      * We have to skip the raw formats, we cannot convert to raw.
> > >>> +      * E.g. 'AR12' (16-bit ARGB 4-4-4-4), 'AR15' (16-bit ARGB 1-5-5-5), etc.
> > >>> +      */
> > >>> +     for (i = 0; i < isc->controller_formats_size; i++) {
> > >>> +             if (isc->controller_formats[i].raw)
> > >>>                        continue;
> > >>> -             if (supported_index == index) {
> > >>> -                     f->pixelformat = isc->formats_list[i].fourcc;
> > >>> +             if (index == supported_index) {
> > >>> +                     f->pixelformat = isc->controller_formats[i].fourcc;
> > >>>                        return 0;
> > >>>                }
> > >>>                supported_index++;
> > >>> @@ -584,20 +607,30 @@ 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 &&
> > >>> +         !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;
> > >>>   }
> > >>> @@ -825,7 +858,7 @@ 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;
> > >>> @@ -846,180 +879,140 @@ 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->controller_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;
> > >>> +     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;
> > >>> -
> > >>> -     /*
> > >>> -      * 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;
> > >>> -
> > >>> -     v4l2_fill_pix_format(pixfmt, &format.format);
> > >>> +     v4l_bound_align_image(&pixfmt->width, 16, isc->max_width, 0,
> > >>> +                           &pixfmt->height, 16, isc->max_height, 0, 0);
> > >>> +     /* 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;
> > >>>
> > >>> -     /* 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;
> > >>>
> > >>> -     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;
> > >>>
> > >>> -     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->formats_list_size; i++)
> > >>> +             if (isc->formats_list[i].mbus_code == format.format.code) {
> > >>> +                     sd_fmt = &isc->formats_list[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);
> > >>>
> > >>> -     isc->fmt = *f;
> > >>> +     /* 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;
> > >>> +     }
> > >>>
> > >>> +     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");
> > >>> @@ -1043,7 +1036,7 @@ 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,
> > >>> @@ -1098,10 +1091,6 @@ static int isc_enum_framesizes(struct file *file, void *fh,
> > >>>        if (fsize->index)
> > >>>                return -EINVAL;
> > >>>
> > >>> -     for (i = 0; i < isc->num_user_formats; i++)
> > >>> -             if (isc->user_formats[i]->fourcc == fsize->pixel_format)
> > >>> -                     ret = 0;
> > >>> -
> > >>>        for (i = 0; i < isc->controller_formats_size; i++)
> > >>>                if (isc->controller_formats[i].fourcc == fsize->pixel_format)
> > >>>                        ret = 0;
> > >>> @@ -1782,52 +1771,6 @@ struct isc_format *isc_find_format_by_code(struct isc_device *isc,
> > >>>   }
> > >>>   EXPORT_SYMBOL_GPL(isc_find_format_by_code);
> > >>>
> > >>> -static int isc_formats_init(struct isc_device *isc)
> > >>> -{
> > >>> -     struct isc_format *fmt;
> > >>> -     struct v4l2_subdev *subdev = isc->current_subdev->sd;
> > >>> -     unsigned int num_fmts, i, j;
> > >>> -     u32 list_size = isc->formats_list_size;
> > >>> -     struct v4l2_subdev_mbus_code_enum mbus_code = {
> > >>> -             .which = V4L2_SUBDEV_FORMAT_ACTIVE,
> > >>> -     };
> > >>> -
> > >>> -     num_fmts = 0;
> > >>> -     while (!v4l2_subdev_call(subdev, pad, enum_mbus_code,
> > >>> -            NULL, &mbus_code)) {
> > >>> -             mbus_code.index++;
> > >>> -
> > >>> -             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);
> > >>> -                     continue;
> > >>> -             }
> > >>> -
> > >>> -             fmt->sd_support = true;
> > >>> -             num_fmts++;
> > >>> -     }
> > >>> -
> > >>> -     if (!num_fmts)
> > >>> -             return -ENXIO;
> > >>> -
> > >>> -     isc->num_user_formats = num_fmts;
> > >>> -     isc->user_formats = devm_kcalloc(isc->dev,
> > >>> -                                      num_fmts, sizeof(*isc->user_formats),
> > >>> -                                      GFP_KERNEL);
> > >>> -     if (!isc->user_formats)
> > >>> -             return -ENOMEM;
> > >>> -
> > >>> -     fmt = &isc->formats_list[0];
> > >>> -     for (i = 0, j = 0; i < list_size; i++) {
> > >>> -             if (fmt->sd_support)
> > >>> -                     isc->user_formats[j++] = fmt;
> > >>> -             fmt++;
> > >>> -     }
> > >>> -
> > >>> -     return 0;
> > >>> -}
> > >>> -
> > >>>   static int isc_set_default_fmt(struct isc_device *isc)
> > >>>   {
> > >>>        struct v4l2_format f = {
> > >>> @@ -1836,12 +1779,12 @@ static int isc_set_default_fmt(struct isc_device *isc)
> > >>>                        .width          = VGA_WIDTH,
> > >>>                        .height         = VGA_HEIGHT,
> > >>>                        .field          = V4L2_FIELD_NONE,
> > >>> -                     .pixelformat    = isc->user_formats[0]->fourcc,
> > >>> +                     .pixelformat    = isc->controller_formats[0].fourcc,
> > >>>                },
> > >>>        };
> > >>>        int ret;
> > >>>
> > >>> -     ret = isc_try_fmt(isc, &f, NULL);
> > >>> +     ret = isc_try_fmt(isc, &f);
> > >>>        if (ret)
> > >>>                return ret;
> > >>>
> > >>> @@ -1896,13 +1839,6 @@ static int isc_async_complete(struct v4l2_async_notifier *notifier)
> > >>>        spin_lock_init(&isc->dma_queue_lock);
> > >>>        spin_lock_init(&isc->awb_lock);
> > >>>
> > >>> -     ret = isc_formats_init(isc);
> > >>> -     if (ret < 0) {
> > >>> -             v4l2_err(&isc->v4l2_dev,
> > >>> -                      "Init format failed: %d\n", ret);
> > >>> -             goto isc_async_complete_err;
> > >>> -     }
> > >>> -
> > >>>        ret = isc_set_default_fmt(isc);
> > >>>        if (ret) {
> > >>>                v4l2_err(&isc->v4l2_dev, "Could not set default format\n");
> > >>> @@ -2016,6 +1952,24 @@ int isc_pipeline_init(struct isc_device *isc)
> > >>>   }
> > >>>   EXPORT_SYMBOL_GPL(isc_pipeline_init);
> > >>>
> > >>> +static 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;
> > >>> +
> > >>> +     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;
> > >>> @@ -2023,6 +1977,8 @@ 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 a1ca4633787c..2b0621297dfe 100644
> > >>> --- a/drivers/media/platform/atmel/atmel-isc-scaler.c
> > >>> +++ b/drivers/media/platform/atmel/atmel-isc-scaler.c
> > >>> @@ -173,6 +173,10 @@ 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,
> > >>>   };
> > >>> @@ -190,6 +194,7 @@ 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 f98f25a55e73..5b0100c8c245 100644
> > >>> --- a/drivers/media/platform/atmel/atmel-isc.h
> > >>> +++ b/drivers/media/platform/atmel/atmel-isc.h
> > >>> @@ -63,15 +63,16 @@ struct isc_subdev_entity {
> > >>>    * @cfa_baycfg:              If this format is RAW BAYER, indicate the type of bayer.
> > >>>                        this is either BGBG, RGRG, etc.
> > >>>    * @pfe_cfg0_bps:    Number of hardware data lines connected to the ISC
> > >>> + * @raw:             If the format is raw bayer.
> > >>>    */
> > >>>
> > >>>   struct isc_format {
> > >>>        u32     fourcc;
> > >>>        u32     mbus_code;
> > >>>        u32     cfa_baycfg;
> > >>> -
> > >>> -     bool    sd_support;
> > >>>        u32     pfe_cfg0_bps;
> > >>> +
> > >>> +     bool    raw;
> > >>>   };
> > >>>
> > >>>   /* Pipeline bitmap */
> > >>> @@ -216,8 +217,7 @@ enum isc_scaler_pads {
> > >>>    * @comp:            completion reference that signals frame completion
> > >>>    *
> > >>>    * @fmt:             current v42l format
> > >>> - * @user_formats:    list of formats that are supported and agreed with sd
> > >>> - * @num_user_formats:        how many formats are in user_formats
> > >>> + * @try_fmt:         current v4l2 try format
> > >>>    *
> > >>>    * @config:          current ISC format configuration
> > >>>    * @try_config:              the current ISC try format , not yet activated
> > >>> @@ -272,6 +272,7 @@ 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
> > >>> @@ -298,8 +299,7 @@ struct isc_device {
> > >>>        struct completion       comp;
> > >>>
> > >>>        struct v4l2_format      fmt;
> > >>> -     struct isc_format       **user_formats;
> > >>> -     unsigned int            num_user_formats;
> > >>> +     struct v4l2_format      try_fmt;
> > >>>
> > >>>        struct fmt_config       config;
> > >>>        struct fmt_config       try_config;
> > >>> @@ -369,6 +369,7 @@ struct isc_device {
> > >>>        struct {
> > >>>                struct media_pad                pads[ISC_PADS_NUM];
> > >>>                struct media_device             mdev;
> > >>> +             struct media_pipeline           mpipe;
> > >>>
> > >>>                u32                             remote_pad;
> > >>>        };
> > >>> diff --git a/drivers/media/platform/atmel/atmel-sama5d2-isc.c b/drivers/media/platform/atmel/atmel-sama5d2-isc.c
> > >>> index d96ee3373889..2a651e237193 100644
> > >>> --- a/drivers/media/platform/atmel/atmel-sama5d2-isc.c
> > >>> +++ b/drivers/media/platform/atmel/atmel-sama5d2-isc.c
> > >>> @@ -80,20 +80,40 @@ static const struct isc_format sama5d2_controller_formats[] = {
> > >>>                .fourcc         = V4L2_PIX_FMT_Y10,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SBGGR8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGBRG8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGRBG8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SRGGB8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SBGGR10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGBRG10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGRBG10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SRGGB10,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SBGGR12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SGBRG12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SGRBG12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SRGGB12,
> > >>> +             .raw            = true,
> > >>>        },
> > >>>   };
> > >>>
> > >>> diff --git a/drivers/media/platform/atmel/atmel-sama7g5-isc.c b/drivers/media/platform/atmel/atmel-sama7g5-isc.c
> > >>> index e07ae188c15f..a0d60cfdba7b 100644
> > >>> --- a/drivers/media/platform/atmel/atmel-sama7g5-isc.c
> > >>> +++ b/drivers/media/platform/atmel/atmel-sama7g5-isc.c
> > >>> @@ -89,20 +89,40 @@ static const struct isc_format sama7g5_controller_formats[] = {
> > >>>                .fourcc         = V4L2_PIX_FMT_Y16,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SBGGR8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGBRG8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGRBG8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SRGGB8,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SBGGR10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGBRG10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SGRBG10,
> > >>> +             .raw            = true,
> > >>>        }, {
> > >>>                .fourcc         = V4L2_PIX_FMT_SRGGB10,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SBGGR12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SGBRG12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SGRBG12,
> > >>> +             .raw            = true,
> > >>> +     }, {
> > >>> +             .fourcc         = V4L2_PIX_FMT_SRGGB12,
> > >>> +             .raw            = true,
> > >>>        },
> > >>>   };
> > >>>

-- 
Regards,

Laurent Pinchart