Re: [RFC PATCH v3 4/6] media: tegra: Add Tegra210 Video input driver

[Sowjanya Komatineni <skomatineni@nvidia.com>]

On 2/25/20 8:49 PM, Sowjanya Komatineni wrote:
>
> On 2/20/20 4:44 AM, Hans Verkuil wrote:
>> External email: Use caution opening links or attachments
>>
>>
>> Hi Sowjanya,
>>
>> Some code review comments below:
>>
>> On 2/14/20 7:23 PM, Sowjanya Komatineni wrote:
>>> Tegra210 contains a powerful Video Input (VI) hardware controller
>>> which can support up to 6 MIPI CSI camera sensors.
>>>
>>> Each Tegra CSI port can be one-to-one mapped to VI channel and can
>>> capture from an external camera sensor connected to CSI or from
>>> built-in test pattern generator.
>>>
>>> Tegra210 supports built-in test pattern generator from CSI to VI.
>>>
>>> This patch adds a V4L2 media controller and capture driver support
>>> for Tegra210 built-in CSI to VI test pattern generator.
>>>
>>> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
>>> ---
>>>   drivers/staging/media/Kconfig              |    2 +
>>>   drivers/staging/media/Makefile             |    1 +
>>>   drivers/staging/media/tegra/Kconfig        |   10 +
>>>   drivers/staging/media/tegra/Makefile       |    8 +
>>>   drivers/staging/media/tegra/TODO           |   10 +
>>>   drivers/staging/media/tegra/tegra-common.h |  239 +++++++
>>>   drivers/staging/media/tegra/tegra-csi.c    |  374 ++++++++++
>>>   drivers/staging/media/tegra/tegra-csi.h    |  115 ++++
>>>   drivers/staging/media/tegra/tegra-vi.c     | 1019 
>>> ++++++++++++++++++++++++++++
>>>   drivers/staging/media/tegra/tegra-vi.h     |   79 +++
>>>   drivers/staging/media/tegra/tegra-video.c  |  118 ++++
>>>   drivers/staging/media/tegra/tegra-video.h  |   32 +
>>>   drivers/staging/media/tegra/tegra210.c     |  767 
>>> +++++++++++++++++++++
>>>   drivers/staging/media/tegra/tegra210.h     |  190 ++++++
>>>   14 files changed, 2964 insertions(+)
>>>   create mode 100644 drivers/staging/media/tegra/Kconfig
>>>   create mode 100644 drivers/staging/media/tegra/Makefile
>>>   create mode 100644 drivers/staging/media/tegra/TODO
>>>   create mode 100644 drivers/staging/media/tegra/tegra-common.h
>>>   create mode 100644 drivers/staging/media/tegra/tegra-csi.c
>>>   create mode 100644 drivers/staging/media/tegra/tegra-csi.h
>>>   create mode 100644 drivers/staging/media/tegra/tegra-vi.c
>>>   create mode 100644 drivers/staging/media/tegra/tegra-vi.h
>>>   create mode 100644 drivers/staging/media/tegra/tegra-video.c
>>>   create mode 100644 drivers/staging/media/tegra/tegra-video.h
>>>   create mode 100644 drivers/staging/media/tegra/tegra210.c
>>>   create mode 100644 drivers/staging/media/tegra/tegra210.h
>>>
>
>>> +static int chan_capture_kthread_done(void *data)
>>> +{
>>> +     struct tegra_vi_channel *chan = data;
>>> +     struct tegra_channel_buffer *buf;
>>> +
>>> +     set_freezable();
>>> +
>>> +     while (1) {
>>> +             try_to_freeze();
>>> +
>>> +             wait_event_interruptible(chan->done_wait,
>>> + !list_empty(&chan->done) ||
>>> +                                      kthread_should_stop());
>>> +
>>> +             if (kthread_should_stop())
>>> +                     break;
>> I think it makes more sense if this test is moved to the end...
>>
>>> +
>>> +             buf = dequeue_buf_done(chan);
>>> +             if (!buf)
>>> +                     continue;
>> ... and this becomes:
>>
>>                  if (buf)
>>> + tegra_channel_capture_done(chan, buf);
>> This change simplifies stop_streaming (see below).
>
> With kthread_should_stop check at end, I see sometimes outstanding 
> buffer in done queue by the time threads are stopped during stream stop.
>
> When I run compliance stream io tests continuously in loop, depending 
> on time of stream stop request capture thread terminated after 
> initiating frame capture and moving buffer to done queue while done 
> thread was still in wait for previous MW_ACK and on seeing 
> kthread_should_stop done thread terminated with last buffer left in 
> done queue.
>
> So looks like we need to keep checking for outstanding buffer and 
> handle it during stop streaming like in v3.
>
Will change in v4 to handle all pending done queue buffers before 
terminating thread.
>
>>> +     }
>>> +
>>> +     return 0;
>>> +}
>>> +
>>> +int tegra210_vi_start_streaming(struct vb2_queue *vq, u32 count)
>>> +{
>>> +     struct tegra_vi_channel *chan = vb2_get_drv_priv(vq);
>>> +     struct media_pipeline *pipe = &chan->video.pipe;
>>> +     int ret = 0;
>>> +
>>> +     tegra_vi_write(chan, TEGRA_VI_CFG_CG_CTRL, VI_CG_2ND_LEVEL_EN);
>>> +
>>> +     /* clear errors */
>>> +     vi_csi_write(chan, TEGRA_VI_CSI_ERROR_STATUS, 0xFFFFFFFF);
>>> +
>>> +     /*
>>> +      * Sync point FIFO full stalls the host interface.
>>> +      * Setting NO_STALL will drop INCR_SYNCPT methods when fifos are
>>> +      * full and the corresponding condition bits in INCR_SYNCPT_ERROR
>>> +      * register will be set.
>>> +      * This allows SW to process error recovery.
>>> +      */
>>> +     tegra_vi_write(chan, TEGRA_VI_CFG_VI_INCR_SYNCPT_CNTRL,
>>> +                    TEGRA_VI_CFG_VI_INCR_SYNCPT_NO_STALL);
>>> +
>>> +     /* start the pipeline */
>>> +     ret = media_pipeline_start(&chan->video.entity, pipe);
>>> +     if (ret < 0)
>>> +             goto error_pipeline_start;
>>> +
>>> +     /* program VI registers after TPG, sensors and CSI streaming */
>>> +     ret = tegra_channel_set_stream(chan, true);
>>> +     if (ret < 0)
>>> +             goto error_set_stream;
>>> +
>>> +     tegra_channel_capture_setup(chan);
>>> +
>>> +     chan->sequence = 0;
>>> +
>>> +     /* start kthreads to capture data to buffer and return them */
>>> +     chan->kthread_capture_done = 
>>> kthread_run(chan_capture_kthread_done,
>>> +                                              chan, "%s:1",
>>> + chan->video.name);
>>> +     if (IS_ERR(chan->kthread_capture_done)) {
>>> +             ret = PTR_ERR(chan->kthread_capture_done);
>>> +             chan->kthread_capture_done = NULL;
>>> +             dev_err(&chan->video.dev,
>>> +                     "failed capture done kthread: %d\n", ret);
>>> +             goto error_kthread_done;
>>> +     }
>>> +
>>> +     chan->kthread_capture_start = 
>>> kthread_run(chan_capture_kthread_start,
>>> +                                               chan, "%s:0",
>>> + chan->video.name);
>>> +     if (IS_ERR(chan->kthread_capture_start)) {
>>> +             ret = PTR_ERR(chan->kthread_capture_start);
>>> +             chan->kthread_capture_start = NULL;
>>> +             dev_err(&chan->video.dev,
>>> +                     "failed capture start kthread: %d\n", ret);
>>> +             goto error_kthread_start;
>>> +     }
>>> +
>>> +     return 0;
>>> +
>>> +error_kthread_start:
>>> +     kthread_stop(chan->kthread_capture_done);
>>> +error_kthread_done:
>>> +     tegra_channel_set_stream(chan, false);
>>> +error_set_stream:
>>> +     media_pipeline_stop(&chan->video.entity);
>>> +error_pipeline_start:
>>> +     vq->start_streaming_called = 0;
>>> +     tegra_channel_release_queued_buffers(chan, VB2_BUF_STATE_QUEUED);
>>> +     return ret;
>>> +}
>>> +
>>> +void tegra210_vi_stop_streaming(struct vb2_queue *vq)
>>> +{
>>> +     struct tegra_vi_channel *chan = vb2_get_drv_priv(vq);
>>> +     struct tegra_channel_buffer *buf;
>>> +
>>> +     if (!chan->kthread_capture_start || !chan->kthread_capture_done)
>>> +             return;
>>> +
>>> +     kthread_stop(chan->kthread_capture_start);
>>> +     chan->kthread_capture_start = NULL;
>>> +     kthread_stop(chan->kthread_capture_done);
>>> +     chan->kthread_capture_done = NULL;
>>> +
>> With the change in chan_capture_kthread_done() as described above you 
>> can
>> drop the next 4 lines since that's guaranteed to be done by the thread.
>>
>>> +     /* wait for last frame MW_ACK_DONE */
>>> +     buf = dequeue_buf_done(chan);
>>> +     if (buf)
>>> +             tegra_channel_capture_done(chan, buf);
>>> +
>>> +     tegra_channel_release_queued_buffers(chan, VB2_BUF_STATE_ERROR);
>>> +
>>> +     tegra_channel_set_stream(chan, false);
>>> +
>>> +     /* disable clock gating to enable continuous clock */
>>> +     tegra_vi_write(chan, TEGRA_VI_CFG_CG_CTRL, 0);
>>> +
>>> +     /* reset VI MCIF, PF, SENSORCTL, and SHADOW logic */
>>> +     vi_csi_write(chan, TEGRA_VI_CSI_SW_RESET, 0xF);
>>> +     vi_csi_write(chan, TEGRA_VI_CSI_SW_RESET, 0x0);
>>> +     vi_csi_write(chan, TEGRA_VI_CSI_IMAGE_DEF, 0);
>>> +
>>> +     /* enable clock gating so VI can be clock gated if necessary */
>>> +     tegra_vi_write(chan, TEGRA_VI_CFG_CG_CTRL, VI_CG_2ND_LEVEL_EN);
>>> +     vi_csi_write(chan, TEGRA_VI_CSI_ERROR_STATUS, 0xFFFFFFFF);
>>> +
>>> +     media_pipeline_stop(&chan->video.entity);
>>> +}
>>> +
>>> +void tegra210_csi_error_recover(struct tegra_csi_channel *csi_chan)
>>
>> Regards,
>>
>>          Hans