Il 04/11/24 14:20, Krzysztof Wilczyński ha scritto:
Hello,
+ ret = of_property_read_u32(dev->of_node, "num-lanes", &num_lanes);
+ if (ret == 0) {
+ if (num_lanes == 0 || num_lanes > 16 || (num_lanes != 1 && num_lanes % 2))
+ dev_warn(dev, "Invalid num-lanes, using controller defaults\n");
+ else
+ pcie->num_lanes = num_lanes;
+ }
+
return 0;
}
If you were to handle non-zero return value as an error here, perhaps the
property has not been set, then we could reduce the indentation here.
Something like this, perhaps?
ret = of_property_read_u32(dev->of_node, "num-lanes", &num_lanes);
if (ret) {
dev_err(dev, "Failed to read num-lanes: %d\n", ret);
return ret;
}
if (!num_lanes || num_lanes > 16 || (num_lanes != 1 && num_lanes % 2))
dev_warn(dev, "Invalid num-lanes, using controller defaults\n");
else
pcie->num_lanes = num_lanes;
Does this make sense here? Thoughts?
Krzysztof
Sorry I've just seen this email.
There's a problem here: this property has to be optional - and if you change that
to return like that, you're breaking compatibility with older device trees, which
are not specifying any "num-lanes" property.
Please remember that of_property_read_u32() returns:
- 0 on success
- -EINVAL if the property does not exist
- -ENODATA or -EOVERFLOW
Please either keep the error checking like I wrote, or alternatively you can do..
ret = of_property_read_u32(...)
if (ret != -EINVAL) {
dev_err(dev, "Failed to read num-lanes: %d\n", ret);
return ret;
} else {
if (num_lanes == 0 || ..... etc etc)
dev_warn()
else
pcie->num_lanes = num_lanes
}
Cheers,
Angelo
