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Date:   Wed, 22 Apr 2020 10:57:23 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        linux-remoteproc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-stm32@st-md-mailman.stormreply.com
Subject: Re: [RFC 02/18] remoteproc: Introduce virtio device add/remove
 functions in core.
Message-ID: <20200422165723.GA9283@xps15>
References: <20200416161331.7606-1-arnaud.pouliquen@st.com>
 <20200416161331.7606-3-arnaud.pouliquen@st.com>
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This morning I'm attempting to take a fresh look at this set...

On Thu, Apr 16, 2020 at 06:13:15PM +0200, Arnaud Pouliquen wrote:
> In preparation of the migration of the management of rvdev in
> rproc_virtio, this patch spins off new functions to manage the
> virtio device.
> 
> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
> ---
>  drivers/remoteproc/remoteproc_core.c | 149 +++++++++++++++------------
>  1 file changed, 83 insertions(+), 66 deletions(-)
> 
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index 2a0425ab82a7..5c90d569c0f7 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -441,6 +441,86 @@ static void rproc_rvdev_release(struct device *dev)
>  	kfree(rvdev);
>  }
>  
> +static int rproc_rvdev_add_device(struct rproc_vdev *rvdev)
> +{
> +	struct rproc *rproc = rvdev->rproc;
> +	struct fw_rsc_vdev *rsc = rvdev->rsc;
> +	char name[16];
> +	int ret, i;
> +
> +	/* Initialise vdev subdevice */
> +	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> +	rvdev->dev.parent = &rproc->dev;
> +	rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
> +	rvdev->dev.release = rproc_rvdev_release;
> +	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> +	dev_set_drvdata(&rvdev->dev, rvdev);
> +
> +	ret = device_register(&rvdev->dev);
> +	if (ret) {
> +		put_device(&rvdev->dev);
> +		return ret;
> +	}
> +	/* Make device dma capable by inheriting from parent's capabilities */
> +	set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
> +
> +	ret = dma_coerce_mask_and_coherent(&rvdev->dev,
> +					   dma_get_mask(rproc->dev.parent));
> +	if (ret) {
> +		dev_warn(&rvdev->dev,
> +			 "Failed to set DMA mask %llx. Trying to continue... %x\n",
> +			 dma_get_mask(rproc->dev.parent), ret);
> +	}
> +
> +	/* parse the vrings */
> +	for (i = 0; i < rsc->num_of_vrings; i++) {
> +		ret = rproc_parse_vring(rvdev, rsc, i);
> +		if (ret)
> +			goto free_rvdev;
> +	}
> +
> +	/* allocate the vring resources */
> +	for (i = 0; i < rsc->num_of_vrings; i++) {
> +		ret = rproc_alloc_vring(rvdev, i);
> +		if (ret)
> +			goto free_vg;
> +	}
> +
> +	rvdev->subdev.start = rproc_vdev_do_start;
> +	rvdev->subdev.stop = rproc_vdev_do_stop;
> +
> +	rproc_add_subdev(rproc, &rvdev->subdev);
> +
> +	return 0;
> +
> +free_vg:
> +	for (i--; i >= 0; i--) {
> +		struct rproc_vring *rvring = &rvdev->vring[i];
> +
> +		rproc_free_vring(rvring);
> +	}
> +
> +free_rvdev:
> +	device_unregister(&rvdev->dev);
> +
> +	return ret;
> +}
> +
> +static void rproc_rvdev_remove_device(struct rproc_vdev *rvdev)
> +{
> +	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);
> +	device_unregister(&rvdev->dev);
> +}
> +
>  /**
>   * rproc_handle_vdev() - handle a vdev fw resource
>   * @rproc: the remote processor
> @@ -473,8 +553,6 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  {
>  	struct device *dev = &rproc->dev;
>  	struct rproc_vdev *rvdev;
> -	int i, ret;
> -	char name[16];
>  
>  	/* make sure resource isn't truncated */
>  	if (struct_size(rsc, vring, rsc->num_of_vrings) + rsc->config_len >
> @@ -505,83 +583,22 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
>  	kref_init(&rvdev->refcount);
>  
>  	rvdev->rsc = rsc;
> +	rvdev->rsc_offset = offset;
>  	rvdev->id = rsc->id;
>  	rvdev->rproc = rproc;
>  	rvdev->index = rproc->nb_vdev++;
>  
> -	/* Initialise vdev subdevice */
> -	snprintf(name, sizeof(name), "vdev%dbuffer", rvdev->index);
> -	rvdev->dev.parent = rproc->dev.parent;
> -	rvdev->dev.dma_pfn_offset = rproc->dev.parent->dma_pfn_offset;
> -	rvdev->dev.release = rproc_rvdev_release;
> -	dev_set_name(&rvdev->dev, "%s#%s", dev_name(rvdev->dev.parent), name);
> -	dev_set_drvdata(&rvdev->dev, rvdev);
> -
> -	ret = device_register(&rvdev->dev);
> -	if (ret) {
> -		put_device(&rvdev->dev);
> -		return ret;
> -	}
> -	/* Make device dma capable by inheriting from parent's capabilities */
> -	set_dma_ops(&rvdev->dev, get_dma_ops(rproc->dev.parent));
> -
> -	ret = dma_coerce_mask_and_coherent(&rvdev->dev,
> -					   dma_get_mask(rproc->dev.parent));
> -	if (ret) {
> -		dev_warn(dev,
> -			 "Failed to set DMA mask %llx. Trying to continue... %x\n",
> -			 dma_get_mask(rproc->dev.parent), ret);
> -	}
> -
> -	/* parse the vrings */
> -	for (i = 0; i < rsc->num_of_vrings; i++) {
> -		ret = rproc_parse_vring(rvdev, rsc, i);
> -		if (ret)
> -			goto free_rvdev;
> -	}
> -
> -	/* remember the resource offset*/
> -	rvdev->rsc_offset = offset;
> -
> -	/* allocate the vring resources */
> -	for (i = 0; i < rsc->num_of_vrings; i++) {
> -		ret = rproc_alloc_vring(rvdev, i);
> -		if (ret)
> -			goto unwind_vring_allocations;
> -	}
> -
>  	list_add_tail(&rvdev->node, &rproc->rvdevs);

This should go in rproc_rvdev_add_device()

>  
> -	rvdev->subdev.start = rproc_vdev_do_start;
> -	rvdev->subdev.stop = rproc_vdev_do_stop;
> -
> -	rproc_add_subdev(rproc, &rvdev->subdev);
> -
> -	return 0;
> -
> -unwind_vring_allocations:
> -	for (i--; i >= 0; i--)
> -		rproc_free_vring(&rvdev->vring[i]);
> -free_rvdev:
> -	device_unregister(&rvdev->dev);
> -	return ret;
> +	return rproc_rvdev_add_device(rvdev);
>  }
>  
>  void rproc_vdev_release(struct kref *ref)
>  {
>  	struct rproc_vdev *rvdev = container_of(ref, struct rproc_vdev, refcount);
> -	struct rproc_vring *rvring;
> -	struct rproc *rproc = rvdev->rproc;
> -	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_rvdev_remove_device(rvdev);
>  	list_del(&rvdev->node);
> -	device_unregister(&rvdev->dev);

Keep this function intact, rename it rproc_rvdev_remove_device() to balance out
rproc_rvdev_add_device() and modify rproc_resource_cleanup() to reflect the
change.  I suppose we have nothing to loose since rproc_handle_vdev() and
rproc_vdev_release(), from a syntactic point of view, didn't balance each other
out.

>  }
>  
>  /**
> -- 
> 2.17.1
>