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Date: Thu, 28 Mar 2024 08:38:52 -0600
From: Mathieu Poirier <mathieu.poirier@linaro.org>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Cc: andersson@kernel.org, matthias.bgg@gmail.com, tzungbi@kernel.org,
	tinghan.shen@mediatek.com, linux-remoteproc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-mediatek@lists.infradead.org, wenst@chromium.org,
	kernel@collabora.com
Subject: Re: [PATCH 2/2] remoteproc: mediatek: Don't parse extraneous
 subnodes for multi-core
Message-ID: <ZgWA/E46i/CaoM74@p14s>
References: <20240321084614.45253-1-angelogioacchino.delregno@collabora.com>
 <20240321084614.45253-3-angelogioacchino.delregno@collabora.com>
 <ZfxRyMyUqyqtXy8n@p14s>
 <9ef4e974-740e-4698-bb38-f236521a425c@collabora.com>
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On Wed, Mar 27, 2024 at 01:49:58PM +0100, AngeloGioacchino Del Regno wrote:
> Il 21/03/24 16:27, Mathieu Poirier ha scritto:
> > On Thu, Mar 21, 2024 at 09:46:14AM +0100, AngeloGioacchino Del Regno wrote:
> > > When probing multi-core SCP, this driver is parsing all sub-nodes of
> > > the scp-cluster node, but one of those could be not an actual SCP core
> > > and that would make the entire SCP cluster to fail probing for no good
> > > reason.
> > > 
> > > To fix that, in scp_add_multi_core() treat a subnode as a SCP Core by
> > > parsing only available subnodes having compatible "mediatek,scp-core".
> > > 
> > > Fixes: 1fdbf0cdde98 ("remoteproc: mediatek: Probe SCP cluster on multi-core SCP")
> > > Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> > > ---
> > >   drivers/remoteproc/mtk_scp.c | 3 +++
> > >   1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> > > index 67518291a8ad..fbe1c232dae7 100644
> > > --- a/drivers/remoteproc/mtk_scp.c
> > > +++ b/drivers/remoteproc/mtk_scp.c
> > > @@ -1096,6 +1096,9 @@ static int scp_add_multi_core(struct platform_device *pdev,
> > >   	cluster_of_data = (const struct mtk_scp_of_data **)of_device_get_match_data(dev);
> > >   	for_each_available_child_of_node(np, child) {
> > > +		if (!of_device_is_compatible(child, "mediatek,scp-core"))
> > > +			continue;
> > > +
> > 
> > Interesting - what else gets stashed under the remote processor node?  I don't
> > see anything specified in the bindings.
> > 
> 
> Sorry for the late reply - well, in this precise moment in time, upstream,
> nothing yet.
> 
> I have noticed this while debugging some lockups and wanted to move the scp_adsp
> clock controller node as child of the SCP node (as some of those clocks are located
> *into the SCP's CFG register space*, and it's correct for that to be a child as one
> of those do depend on the SCP being up - and I'll spare you the rest) and noticed
> the unexpected behavior, as the SCP driver was treating those as an SCP core.
> 
> There was no kernel panic, but the SCP would fail probing.
> 
> This is anyway a missed requirement ... for platforms that want *both* two SCP
> cores *and* the AudioDSP, as that'd at least be two nodes with the same iostart
> (scp@1072000, clock-controller@1072000), other than the reasons I explained some
> lines back.
> 
> ...and that's why this commit was sent :-)
>

Please update the bindings with the extra clock requirement in your next
revision. 

> P.S.: The reason why platforms don't crash without the scp_adsp clock controller
>       as a child of SCP is that the bootloader is actually doing basic init for
>       the SCP, hence the block is powered on when booting ;-)
> 
> Cheers,
> Angelo
> 
> > Thanks,
> > Mathieu
> > 
> > >   		if (!cluster_of_data[core_id]) {
> > >   			ret = -EINVAL;
> > >   			dev_err(dev, "Not support core %d\n", core_id);
> > > -- 
> > > 2.44.0
> > > 
> 
>