Re: [RFC PATCH v2 5/6] remoteproc: virtio: Add helper to create platform device

[Mathieu Poirier <mathieu.poirier@linaro.org>]

Hi Arnaud,

On Wed, Dec 22, 2021 at 09:23:48AM +0100, Arnaud Pouliquen wrote:
> Add capability to create platform device for the rproc virtio.
> This is a step to move forward the management of the rproc virtio
> as an independent device.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
> ---
>  drivers/remoteproc/remoteproc_internal.h |  3 ++
>  drivers/remoteproc/remoteproc_virtio.c   | 36 ++++++++++++++++++++++++
>  2 files changed, 39 insertions(+)
> 
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index 6f511c50a15d..3007d29a26e1 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -37,6 +37,9 @@ int rproc_of_parse_firmware(struct device *dev, int index,
>  
>  /* from remoteproc_virtio.c */
>  int rproc_rvdev_add_device(struct rproc_vdev *rvdev);
> +struct platform_device *
> +rproc_virtio_register_device(struct rproc *rproc, struct rproc_vdev_pdata *vdev_data);
> +void rproc_virtio_unregister_device(struct rproc_vdev *rvdev);
>  irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id);
>  void rproc_vdev_release(struct kref *ref);
>  
> diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> index 5f8005caeb6e..5eef679cc520 100644
> --- a/drivers/remoteproc/remoteproc_virtio.c
> +++ b/drivers/remoteproc/remoteproc_virtio.c
> @@ -578,6 +578,42 @@ void rproc_vdev_release(struct kref *ref)
>  	rproc_rvdev_remove_device(rvdev);
>  }
>  
> +/**
> + * rproc_virtio_register_device() - register a remoteproc virtio device
> + * @rproc: rproc handle to add the remoteproc virtio device to
> + * @vdev_data: platform device data
> + *
> + * Return: 0 on success, and an appropriate error value otherwise
> + */
> +struct platform_device *
> +rproc_virtio_register_device(struct rproc *rproc, struct rproc_vdev_pdata *vdev_data)
> +{
> +	struct device *dev = &rproc->dev;
> +	struct platform_device *pdev;
> +
> +	pdev = platform_device_register_data(dev, "rproc-virtio", vdev_data->index, vdev_data,
> +					     sizeof(*vdev_data));
> +	if (PTR_ERR_OR_ZERO(pdev)) {

Can you expand on the reason to use PTR_ERR_OR_ZERO() rather than IS_ERR()?
Looking at the documentation for platform_device_register_data(), it should not
return 0...

> +		dev_err(rproc->dev.parent,
> +			"failed to create rproc-virtio device\n");
> +	}
> +
> +	return  pdev;
> +}
> +EXPORT_SYMBOL(rproc_virtio_register_device);
> +
> +/**
> + * rproc_virtio_unregister_device() - unregister a remoteproc virtio device
> + * @rvdev: remote proc virtio handle to unregister
> + *
> + */
> +void rproc_virtio_unregister_device(struct rproc_vdev *rvdev)
> +{
> +	if (rvdev->pdev)
> +		platform_device_unregister(rvdev->pdev);
> +}
> +EXPORT_SYMBOL(rproc_virtio_unregister_device);
> +
>  static int rproc_virtio_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> -- 
> 2.17.1
>