linux-kernel - Re: [RFC PATCH 5/7] remoteproc: virtio: Create platform device for the remoteproc

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Date:   Fri, 22 Oct 2021 11:40:17 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-stm32@...md-mailman.stormreply.com,
        Rob Herring <robh@...nel.org>, Christoph Hellwig <hch@....de>,
        Stefano Stabellini <stefanos@...inx.com>,
        Bruce Ashfield <bruce.ashfield@...inx.com>
Subject: Re: [RFC PATCH 5/7] remoteproc: virtio: Create platform device for
 the remoteproc_virtio

The title mentions the creation of a "platform device" but this patch adds a
platform driver interface.

On Fri, Oct 01, 2021 at 12:12:32PM +0200, Arnaud Pouliquen wrote:
> Define a platform device for the remoteproc virtio to prepare the
> management of the remoteproc virtio as a platform device.

The above should be:

"Define a platform driver to prepare for the managemnt of remoteproc virtio
devices as platform devices."

> 
> The platform device allows to pass rproc_vdev_data platform data to
> specify properties that are stored in the rproc_vdev structure.
> 
> Such approach will allow to preserve legacy remoteproc virtio device
> creation but also to probe the device using device tree mechanism.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@...s.st.com>
> ---
>  drivers/remoteproc/remoteproc_internal.h |  6 +++
>  drivers/remoteproc/remoteproc_virtio.c   | 65 ++++++++++++++++++++++++
>  include/linux/remoteproc.h               |  2 +
>  3 files changed, 73 insertions(+)
> 
> diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
> index 4ce012c353c0..1b963a8912ed 100644
> --- a/drivers/remoteproc/remoteproc_internal.h
> +++ b/drivers/remoteproc/remoteproc_internal.h
> @@ -24,6 +24,12 @@ struct rproc_debug_trace {
>  	struct rproc_mem_entry trace_mem;
>  };
>  
> +struct rproc_vdev_data {
> +	u32 rsc_offset;
> +	unsigned int id;
> +	unsigned int index;
> +};
> +
>  /* from remoteproc_core.c */
>  void rproc_release(struct kref *kref);
>  int rproc_of_parse_firmware(struct device *dev, int index,
> diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
> index c9eecd2f9fb2..9b2ab79e4c4c 100644
> --- a/drivers/remoteproc/remoteproc_virtio.c
> +++ b/drivers/remoteproc/remoteproc_virtio.c
> @@ -4,6 +4,7 @@
>   *
>   * Copyright (C) 2011 Texas Instruments, Inc.
>   * Copyright (C) 2011 Google, Inc.
> + * Copyright (C) 2021 STMicroelectronics
>   *
>   * Ohad Ben-Cohen <ohad@...ery.com>
>   * Brian Swetland <swetland@...gle.com>
> @@ -13,6 +14,7 @@
>  #include <linux/dma-map-ops.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/export.h>
> +#include <linux/of_platform.h>
>  #include <linux/of_reserved_mem.h>
>  #include <linux/remoteproc.h>
>  #include <linux/virtio.h>
> @@ -571,3 +573,66 @@ void rproc_vdev_release(struct kref *ref)
>  
>  	rproc_rvdev_remove_device(rvdev);
>  }
> +
> +static int rproc_virtio_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct rproc_vdev_data *vdev_data = dev->platform_data;
> +	struct rproc_vdev *rvdev;
> +	struct rproc *rproc;
> +
> +	if (!vdev_data)
> +		return -EINVAL;
> +
> +	rvdev = devm_kzalloc(dev, sizeof(*rvdev), GFP_KERNEL);
> +	if (!rvdev)
> +		return -ENOMEM;
> +
> +	rproc = container_of(dev->parent, struct rproc, dev);
> +
> +	rvdev->rsc_offset = vdev_data->rsc_offset;
> +	rvdev->id = vdev_data->id;
> +	rvdev->index = vdev_data->index;
> +
> +	rvdev->pdev = pdev;
> +	rvdev->rproc = rproc;
> +
> +	platform_set_drvdata(pdev, rvdev);
> +
> +	return rproc_rvdev_add_device(rvdev);
> +}
> +
> +static int rproc_virtio_remove(struct platform_device *pdev)
> +{
> +	struct rproc_vdev *rvdev = dev_get_drvdata(&pdev->dev);
> +	struct rproc *rproc = rvdev->rproc;
> +	struct rproc_vring *rvring;
> +	int id;
> +
> +	for (id = 0; id < ARRAY_SIZE(rvdev->vring); id++) {
> +		rvring = &rvdev->vring[id];
> +		rproc_free_vring(rvring);
> +	}
> +
> +	rproc_remove_subdev(rproc, &rvdev->subdev);
> +	rproc_unregister_rvdev(rvdev);
> +	dev_dbg(&pdev->dev, "virtio dev %d removed\n",  rvdev->index);
> +
> +	return 0;
> +}
> +
> +/* Platform driver */
> +static const struct of_device_id rproc_virtio_match[] = {
> +	{ .compatible = "rproc-virtio", },
> +	{},
> +};
> +
> +static struct platform_driver rproc_virtio_driver = {
> +	.probe		= rproc_virtio_probe,
> +	.remove		= rproc_virtio_remove,
> +	.driver		= {
> +		.name	= "rproc-virtio",
> +		.of_match_table	= rproc_virtio_match,
> +	},
> +};
> +builtin_platform_driver(rproc_virtio_driver);
> diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> index e0600e1e5c17..542a3d4664f2 100644
> --- a/include/linux/remoteproc.h
> +++ b/include/linux/remoteproc.h
> @@ -616,6 +616,7 @@ struct rproc_vring {
>   * struct rproc_vdev - remoteproc state for a supported virtio device
>   * @refcount: reference counter for the vdev and vring allocations
>   * @subdev: handle for registering the vdev as a rproc subdevice
> + * @pdev: remoteproc virtio platform device
>   * @dev: device struct used for reference count semantics
>   * @id: virtio device id (as in virtio_ids.h)
>   * @node: list node
> @@ -628,6 +629,7 @@ struct rproc_vdev {
>  	struct kref refcount;
>  
>  	struct rproc_subdev subdev;
> +	struct platform_device *pdev;
>  	struct device dev;
>  
>  	unsigned int id;
> -- 
> 2.17.1
>