netdev - Re: [PATCH 2/2] net/smsc911x: Move interrupt allocation to open/stop

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Date:   Thu, 1 Sep 2016 15:39:31 -0500
From:   Jeremy Linton <jeremy.linton@....com>
To:     Andrew Lunn <andrew@...n.ch>
Cc:     netdev@...r.kernel.org, steve.glendinning@...well.net,
        sergei.shtylyov@...entembedded.com
Subject: Re: [PATCH 2/2] net/smsc911x: Move interrupt allocation to open/stop

Hi,

On 09/01/2016 02:45 PM, Andrew Lunn wrote:
> On Thu, Sep 01, 2016 at 01:47:44PM -0500, Jeremy Linton wrote:
>> Hi Andrew,
>>
>> 	Thanks for taking a look at this!
>>
>> On 09/01/2016 12:06 PM, Andrew Lunn wrote:
>>> Hi Jeremy
>>>
>>> Please don't add forward references. Move the function earlier in the
>>> file.
>>
>> Ok, but I thought it was a fairly large move due to further
>> dependent functions..
>
> There are a few other options, like moving smsc911x_open() rather than
> the interrupt handler.
>
> And i would suggest what ever you do, make it a separate patch. A
> patch which says: No functional changes, just move functions around as
> needed by later patches, is going to be quick and easy to review.

Yes I put it in another patch, I was busy blasting it out rather than 
checking my email...

>
>>>> +	netif_carrier_off(dev);
>>>
>>> What has this change got to do with interrupt handling?
>>
>> 	This is a whoops, it should be in the previous patch..
>
> Or a patch of its own? You also needs to be careful with ordering
> against the phy_connect.
>
>>>> @@ -2479,38 +2491,18 @@ static int smsc911x_drv_probe(struct platform_device *pdev)
>>>> 	if (retval < 0)
>>>> 		goto out_disable_resources;
>>>>
>>>> -	/* configure irq polarity and type before connecting isr */
>>>> -	if (pdata->config.irq_polarity == SMSC911X_IRQ_POLARITY_ACTIVE_HIGH)
>>>> -		intcfg |= INT_CFG_IRQ_POL_;
>>>> -
>>>> -	if (pdata->config.irq_type == SMSC911X_IRQ_TYPE_PUSH_PULL)
>>>> -		intcfg |= INT_CFG_IRQ_TYPE_;
>>>> -
>>>> -	smsc911x_reg_write(pdata, INT_CFG, intcfg);
>>>
>>>
>>> I see these removes, but where are the adds?
>>
>>
>> 	The functionality is duplicated in open, when the IRQ handler is tested.
>
> Ah, it is obfusticated by SMC_SET_IRQ_CFG().
>
> If you say it is duplicated, how about a separate patch removing it,
> with a clear pointer to where the duplicate is.

? Well, I didn't do that part, but I'm confused by your 
SMC_SET_IRQ_CFG(). AFAIK, that is smc911x not smsc911x. The code in 
question is in smsc911x_open() following "Set interrupt deassertion to 
100uS". It looks a little different but its reprogramming the INT_CFG 
preceding the interrupt being enabled.

Really, if I were feeling brave (because this driver is used in so many 
strange pieces of hardware) I would rewrite a large portion of the 
interrupt management in this driver. I started looking at it last month, 
while looking for the mdio polling issue, because I wanted to get the 
link state changes directly. While at it I noticed the WOL functionality 
could use some attention, etc, one problem after another.