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SubjectRe: [PATCH v6 4/8] media: platform: Add Cedrus VPU decoder driver
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On Wed, 2018-07-25 at 12:02 +0200, Paul Kocialkowski wrote:
> This introduces the Cedrus VPU driver that supports the VPU found in
> Allwinner SoCs, also known as Video Engine. It is implemented through
> a v4l2 m2m decoder device and a media device (used for media requests).
> So far, it only supports MPEG2 decoding.
>
> Since this VPU is stateless, synchronization with media requests is
> required in order to ensure consistency between frame headers that
> contain metadata about the frame to process and the raw slice data that
> is used to generate the frame.
>
> This driver was made possible thanks to the long-standing effort
> carried out by the linux-sunxi community in the interest of reverse
> engineering, documenting and implementing support for Allwinner VPU.
>
> Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
[..]
> +static int cedrus_probe(struct platform_device *pdev)
> +{
> + struct cedrus_dev *dev;
> + struct video_device *vfd;
> + int ret;
> +
> + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
> + if (!dev)
> + return -ENOMEM;
> +
> + dev->dev = &pdev->dev;
> + dev->pdev = pdev;
> +
> + ret = cedrus_hw_probe(dev);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to probe hardware\n");
> + return ret;
> + }
> +
> + dev->dec_ops[CEDRUS_CODEC_MPEG2] = &cedrus_dec_ops_mpeg2;
> +
> + mutex_init(&dev->dev_mutex);
> + spin_lock_init(&dev->irq_lock);
> +

A minor thing.

I believe this spinlock is not needed. All the data structures
it's accessing are already protected, and some operations
(stop_streaming) are guaranteed to not run at the same
time as a job.

Regards,
Eze

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