linux-kernel - Re: [PATCH v2 2/6] firmware: ti

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Message-ID: <dskdxir6375ap47lm2ptp7ttnaaxhczsf6bwk73xl5pajfqhnk@4324gihbq43u>
Date: Wed, 31 Jul 2024 14:36:45 +0200
From: Markus Schneider-Pargmann <msp@...libre.com>
To: Nishanth Menon <nm@...com>
Cc: Tero Kristo <kristo@...nel.org>, 
	Santosh Shilimkar <ssantosh@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Vignesh Raghavendra <vigneshr@...com>, Vibhore Vardhan <vibhore@...com>, 
	Kevin Hilman <khilman@...libre.com>, Dhruva Gole <d-gole@...com>, 
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/6] firmware: ti_sci: Partial-IO support

On Tue, Jul 30, 2024 at 10:07:22AM GMT, Nishanth Menon wrote:
> On 15:01-20240730, Markus Schneider-Pargmann wrote:
> > > > +
> > > > +	return NOTIFY_DONE;
> > > > +}
> > > > +
> > > >  /* Description for K2G */
> > > >  static const struct ti_sci_desc ti_sci_pmmc_k2g_desc = {
> > > >  	.default_host_id = 2,
> > > > @@ -3398,6 +3485,35 @@ static int ti_sci_probe(struct platform_device *pdev)
> > > >  		goto out;
> > > >  	}
> > > >  
> > > > +	if (of_property_read_bool(dev->of_node, "ti,partial-io-wakeup-sources")) {
> > > 
> > > You should probably check on TISCI_MSG_QUERY_FW_CAPS[1] if
> > > Partial IO on low power mode is supported as well? if there is a
> > > mismatch, report so?
> > 
> > I actually have another series in my queue that introduces this check. I
> > just implemented this check for Partial-IO yesterday in the patch that
> > introduces fw capabilities. If you like I can switch these series
> > around.
> 
> Yes, please introduce it part of the series.
> 
> > 
> > > 
> > > > +		info->nr_wakeup_sources =
> > > > +			of_count_phandle_with_args(dev->of_node,
> > > > +						   "ti,partial-io-wakeup-sources",
> > > > +						   NULL);
> > > > +		info->wakeup_source_nodes =
> > > > +			devm_kzalloc(dev, sizeof(*info->wakeup_source_nodes),
> > > > +				     GFP_KERNEL);
> > > > +
> > > > +		for (i = 0; i != info->nr_wakeup_sources; ++i) {
> > > > +			struct device_node *devnode =
> > > > +				of_parse_phandle(dev->of_node,
> > > > +						 "ti,partial-io-wakeup-sources",
> > > > +						 i);
> > > > +			info->wakeup_source_nodes[i] = devnode;
> > > 
> > > Curious: Don't we need to maintain reference counting for the devnode
> > > if CONFIG_OF_DYNAMIC?
> > 
> > In case you mean I missed of_node_put(), yes, I did, thank you. I added
> > it in a ti_sci_remove().
> 
> And unless I am mistaken, of_node_get as required as you are
> retaining the reference of the node till shutdown / remove is invoked.

The function documentation says the refcount is already incremented:

 * Return: The device_node pointer with refcount incremented.  Use
 * of_node_put() on it when done.

Best
Markus

> 
> -- 
> Regards,
> Nishanth Menon
> Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D