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Message-ID: <fa229aa5-5fb7-eb18-3b8a-59d8a98ccaba@foss.st.com>
Date:   Tue, 4 Oct 2022 17:18:17 +0200
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Subject: Re: [PATCH v9 4/4] remoteproc: virtio: Create platform device for the
 remoteproc_virtio
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To:     Rob Herring <robh@kernel.org>
CC:     Bjorn Andersson <andersson@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-stm32@st-md-mailman.stormreply.com>,
        Christoph Hellwig <hch@lst.de>,
        Stefano Stabellini <stefanos@xilinx.com>,
        Bruce Ashfield <bruce.ashfield@xilinx.com>
References: <20220921135044.917140-1-arnaud.pouliquen@foss.st.com>
 <20220921135044.917140-5-arnaud.pouliquen@foss.st.com>
 <20221004143954.GA1479221-robh@kernel.org>
From:   Arnaud POULIQUEN <arnaud.pouliquen@foss.st.com>
In-Reply-To: <20221004143954.GA1479221-robh@kernel.org>
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Hello Rob,

On 10/4/22 16:39, Rob Herring wrote:
> On Wed, Sep 21, 2022 at 03:50:44PM +0200, Arnaud Pouliquen wrote:
>> Define a platform driver to manage the remoteproc virtio device as
>> a 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.
>>
>> remoteproc_virtio.c update:
>>   - Add rproc_virtio_driver platform driver. The probe ops replaces
>>     the rproc_rvdev_add_device function.
>>   - All reference to the rvdev->dev has been updated to rvdev-pdev->dev.
>>   - rproc_rvdev_release is removed as associated to the rvdev device.
>>   - The use of rvdev->kref counter is replaced by get/put_device on the
>>     remoteproc virtio platform device.
>>   - The vdev device no longer increments rproc device counter.
>>     increment/decrement is done in rproc_virtio_probe/rproc_virtio_remove
>>     function in charge of the vrings allocation/free.
>>
>> remoteproc_core.c update:
>>   Migrate from the rvdev device to the rvdev platform device.
>>   From this patch, when a vdev resource is found in the resource table
>>   the remoteproc core register a platform device.
>>
>> Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
>> Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>
>> ---
>>  drivers/remoteproc/remoteproc_core.c     |  12 +-
>>  drivers/remoteproc/remoteproc_internal.h |   2 -
>>  drivers/remoteproc/remoteproc_virtio.c   | 143 ++++++++++++-----------
>>  include/linux/remoteproc.h               |   6 +-
>>  4 files changed, 82 insertions(+), 81 deletions(-)
> 
> [...]
> 
>> +/* Platform driver */
>> +static const struct of_device_id rproc_virtio_match[] = {
>> +	{ .compatible = "virtio,rproc" },
> 
> This is not documented. Add a binding schema if you need DT support.


Mathieu also pointed this out to me in V8, you can see the discussion here [1]

Here is an extract:
"Yes I saw the warning, but for this first series it is not possible to declare
the associated "rproc-virtio" device in device tree.
So at this step it seems not make senses to create the devicetree bindings file.
More than that I don't know how I could justify the properties in bindings if
there is not driver code associated.

So i would be in favor of not adding the bindings in this series but to define
bindings in the first patch of my "step 2" series; as done on my github:
https://github.com/arnopo/linux/commit/9616d89a4f478cf78865a244efcde108d900f69f
"

[1] https://lore.kernel.org/lkml/20220920202201.GB1042164@p14s/ 

Regards,
Arnaud

> 
>> +	{},
>> +};
>> +
>> +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,
>> +	},
>> +};