Subject: Re: Linux-3.14-rc2: Order of serial node compatibles in DTS files.

From: Sebastian Hesselbarth <[email-masked]>
Date: Wed, 12 Feb 2014 09:30:00 +0100

On 02/12/2014 06:28 AM, Kevin Hao wrote:
> On Wed, Feb 12, 2014 at 10:21:58AM +1000, Stephen N Chivers wrote:
>> But, the Interrupt Controller (MPIC)
>> goes AWOL and it is down hill from there.
>>
>> The MPIC is specified in the DTS as:
>>
>>          mpic: pic@40000 {
>>                          interrupt-controller;
>>                          #address-cells = <0>;
>>                          #interrupt-cells = <2>;
>>                          reg = <0x40000 0x40000>;
>>                          compatible = "chrp,open-pic";
>>                          device_type = "open-pic";
>>                          big-endian;
>>                  };
>>
>> The board support file has the standard mechanism for allocating
>> the PIC:
>>
>>          struct mpic *mpic;
>>
>>          mpic = mpic_alloc(NULL, 0, 0, 0, 256, " OpenPIC  ");
>>          BUG_ON(mpic == NULL);
>>
>>          mpic_init(mpic);
>>
>> I checked for damage in applying the patch and it has applied
>> correctly.
>
> How about the following fix?
>
> diff --git a/drivers/of/base.c b/drivers/of/base.c
> index ff85450d5683..ca91984d3c4b 100644
> --- a/drivers/of/base.c
> +++ b/drivers/of/base.c
> @@ -730,32 +730,40 @@ out:
>   }
>   EXPORT_SYMBOL(of_find_node_with_property);
>
> +static int of_match_type_name(const struct device_node *node,
> +				const struct of_device_id *m)

I am fine with having a sub-function here, but it should rather be
named of_match_type_or_name.

> +{
> +	int match = 1;
> +
> +	if (m->name[0])
> +		match &= node->name && !strcmp(m->name, node->name);
> +
> +	if (m->type[0])
> +		match &= node->type && !strcmp(m->type, node->type);
> +
> +	return match;
> +}
[...]
> +	/* Check against matches without compatible string */
> +	m = matches;
> +	while (!m->compatible[0] && (m->name[0] || m->type[0])) {

We shouldn't check for anything else than the sentinel here.
Although I guess yours will not quit early as mine did but that
way we don't have to worry about it.

Sebastian

> +		match = of_match_type_name(node, m);
> +		if (match)
> +			return m;
> +		m++;
> +	}
> +
>   	return NULL;
>   }
>