Re: [PATCH v3 3/3] soc: qcom: apr: Add avs/audio tracking functionality

[Sibi Sankar]

On 2020-01-03 02:27, Bjorn Andersson wrote:
> On Sun 29 Dec 21:00 PST 2019, Sibi Sankar wrote:
> > diff --git a/drivers/soc/qcom/apr.c b/drivers/soc/qcom/apr.c
> [..]
> > -static void of_register_apr_devices(struct device *dev)
> > +static void of_apr_add_pd_lookups(struct device *dev)
> >  {
> > +	const char *service_name, *service_path;
> >  	struct apr *apr = dev_get_drvdata(dev);
> >  	struct device_node *node;
> > +	int ret;
> > +
> > +	for_each_child_of_node(dev->of_node, node) {
> > +		ret = of_property_read_string_index(node, "qcom,protection-domain",
> > +						    0, &service_name);
> > +		if (ret < 0)
> > +			continue;
>
> While this implies that the qcom,protection-domain property is
> missing...
>
> > +
> > +		ret = of_property_read_string_index(node, "qcom,protection-domain",
> > +						    1, &service_path);
> > +		if (ret < 0)
> > +			continue;
>
> ...this would imply that it's there but the format is wrong. I think 
> you
> should log this and propagate the error.
>
> > +
> > +		ret = pdr_add_lookup(&apr->pdr, service_name, service_path);
> > +		if (ret && ret != -EALREADY)
> > +			dev_err(dev, "pdr add lookup failed: %d\n", ret);
>
> So we have a DT that denotes that PDR is required, but we failed to
> register a lookup (for some reason). That would imply that apr is not
> going to work. I think you should propagate this and make apr_probe()
> fail to make this obvious.

this was predominantly done to deal
with a mix of apr devices where some
of them are independent of PDs so
making apr_probe fail is detrimental
here. Also apr devices having improper
format will not be registered or removed.

> > +	}
> > +}
> > +
> > +static void of_register_apr_devices(struct device *dev, const char 
> > *svc_path)
> > +{
> > +	struct apr *apr = dev_get_drvdata(dev);
> > +	struct device_node *node;
> > +	const char *service_path;
> > +	int ret;
> >
> >  	for_each_child_of_node(dev->of_node, node) {
> >  		struct apr_device_id id = { {0} };
>
> I think you should add a comment here describing what's actually going
> on. Something along the lines of:
>
> /*
>  * This function is called with svc_path NULL during apr_probe(), in
>  * which case we register any apr devices without a
>  * qcom,protection-domain specified.
>  *
>  * Then as the protection domains becomes available (if applicable) 
> this
>  * function is again called, but with svc_path representing the service
>  * becoming available. In this case we register any apr devices with a
>  * matching qcom,protection-domain.
>  */

Thanks for writing ^^ up will include
it in my next re-spin.

> > +		ret = of_property_read_string_index(node, "qcom,protection-domain",
> > +						    1, &service_path);
> > +		if (svc_path) {
> > +			/* skip APR services that are PD independent */
> > +			if (ret)
> > +				continue;
> > +
> > +			/* skip APR services whose PD paths don't match */
> > +			if (strcmp(service_path, svc_path))
> > +				continue;
> > +		} else {
> > +			/* skip APR services whose PD lookups are registered */
> > +			if (ret == 0)
> > +				continue;
> > +		}
> > +
>
> Regards,
> Bjorn

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