Re: [PATCH v2 1/2] ARM: OMAP2+: only search for GPMC DT child nodes on probe

[Javier Martinez Canillas <javier.martinez@collabora.co.uk>]

On 04/18/2013 12:33 AM, Jon Hunter wrote:
> 
> On 04/17/2013 05:10 PM, Javier Martinez Canillas wrote:
>> On 04/17/2013 11:27 PM, Jon Hunter wrote:
>>>
>>> On 04/17/2013 03:34 PM, Javier Martinez Canillas wrote:
>>>> The GPMC DT probe function use for_each_node_by_name() to search
>>>> child device nodes of the GPMC controller. But this function does
>>>> not use the GPMC device node as the root of the search and instead
>>>> search across the complete Device Tree.
>>>>
>>>> This means that any device node on the DT that is using any of the
>>>> GPMC child nodes names searched for will be returned even if they
>>>> are not connected to the GPMC, making the gpmc_probe_xxx_child()
>>>> function to fail.
>>>>
>>>> Fix this by using the GPMC device node as the search root so the
>>>> search will be restricted to its children.
>>>>
>>>> Reported-by: Lars Poeschel <poeschel@lemonage.de>
>>>> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
>>>> ---
>>>>
>>>> Changes since v1 (suggested by Jon Hunter):
>>>>   - Split the search for GPMC child nodes and only warn if a
>>>>     child probe fails on two different patches
>>>>   - Don't probe all childs unnecesary if a previous matched
>>>>
>>>>  arch/arm/mach-omap2/gpmc.c |   33 ++++++++++-----------------------
>>>>  1 files changed, 10 insertions(+), 23 deletions(-)
>>>>
>>>> diff --git a/arch/arm/mach-omap2/gpmc.c b/arch/arm/mach-omap2/gpmc.c
>>>> index ed946df..6166847 100644
>>>> --- a/arch/arm/mach-omap2/gpmc.c
>>>> +++ b/arch/arm/mach-omap2/gpmc.c
>>>> @@ -1520,32 +1520,19 @@ static int gpmc_probe_dt(struct platform_device *pdev)
>>>>  		return ret;
>>>>  	}
>>>>  
>>>> -	for_each_node_by_name(child, "nand") {
>>>> -		ret = gpmc_probe_nand_child(pdev, child);
>>>> -		if (ret < 0) {
>>>> -			of_node_put(child);
>>>> -			return ret;
>>>> -		}
>>>> -	}
>>>> +	for_each_child_of_node(pdev->dev.of_node, child) {
>>>>  
>>>> -	for_each_node_by_name(child, "onenand") {
>>>> -		ret = gpmc_probe_onenand_child(pdev, child);
>>>> -		if (ret < 0) {
>>>> -			of_node_put(child);
>>>> -			return ret;
>>>> -		}
>>>> -	}
>>>> +		if (!child->name)
>>>> +			continue;
>>>>  
>>>> -	for_each_node_by_name(child, "nor") {
>>>> -		ret = gpmc_probe_generic_child(pdev, child);
>>>> -		if (ret < 0) {
>>>> -			of_node_put(child);
>>>> -			return ret;
>>>> -		}
>>>> -	}
>>>> +		if (of_node_cmp(child->name, "nand") == 0)
>>>> +			ret = gpmc_probe_nand_child(pdev, child);
>>>> +		else if (of_node_cmp(child->name, "onenand") == 0)
>>>> +			ret = gpmc_probe_onenand_child(pdev, child);
>>>> +		else if (of_node_cmp(child->name, "ethernet") == 0 ||
>>>> +			 of_node_cmp(child->name, "nor") == 0)
>>>> +			ret = gpmc_probe_generic_child(pdev, child);
>>>>  
>>>> -	for_each_node_by_name(child, "ethernet") {
>>>> -		ret = gpmc_probe_generic_child(pdev, child);
>>>>  		if (ret < 0) {
>>>
>>> I think that we need to make sure that "ret" is initialised to 0 at the
>>> beginning of the function. We should not have a case where the child
>> 
>> Hi Jon,
>> 
>> I didn't set ret  to 0 at the beginning of the function since it is assigned the
>> return value of a previous call to of_property_read_u32(). So ret should be 0
>> when execution reaches the for loop.
> 
> Yes you are right, I overlooked that.
> 
>>> name does not match but who knows. Actually that raises another point,
>>> should we have an "else" clause at the end that WARNs on
>>> "unknown/unsupported child" device?
>>>
>> 
>> Actually I thought about it when I was writing that patch and then I decided to
>> not add a WARN for that case since nothing really fail in that case.
>> 
>> I mean if we want to check that a DT is well formed then I think we will need to
>> add much more checks and I don't know if is worth it.
>> 
>> But I don't have a strong opinion on this so if you want I can add it an send a v3.
> 
> Ok, that's fine. I am happy with this version, so no need then to re-do.
>

Great, thanks a lot for your feedback!

Best regards,
Javier