Subject: [PATCH 1/4] net/macb: only probe queues once and use stored values

From: [email-masked] (Nicolas Ferre)
Date: Mon, 30 Mar 2015 08:30:38 +0200

Le 27/03/2015 17:24, Cyrille Pitchen a ?crit :
> Hi Nicolas,
> 
> There is a little mistake in this patch, which will prevent the GEM from 
> working properly:
> 
> Le 27/03/2015 16:34, Nicolas Ferre a ?crit :
>> When merging at91_ether and macb driver during 421d9df0628b (net/macb: merge
>> at91_ether driver into macb driver) the probe function has been split. The code
>> dealing with initialization of queues is now moved in macb_init() which needs
>> information computed in the parent macb_probe() function.
>> So, add the queue_mask information to the private structure and use it when
>> needed in macb_init().
>>
>> Signed-off-by: Nicolas Ferre <[email-masked]>
>> Cc: Cyrille Pitchen <[email-masked]>
>> Cc: Boris Brezillon <[email-masked]>
>> ---
>>  drivers/net/ethernet/cadence/macb.c | 9 ++++-----
>>  drivers/net/ethernet/cadence/macb.h | 1 +
>>  2 files changed, 5 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
>> index a0a04b3638e6..b710768172d9 100644
>> --- a/drivers/net/ethernet/cadence/macb.c
>> +++ b/drivers/net/ethernet/cadence/macb.c
>> @@ -2180,7 +2180,7 @@ static void macb_probe_queues(void __iomem *mem,
>>  static int macb_init(struct platform_device *pdev)
>>  {
>>  	struct net_device *dev = platform_get_drvdata(pdev);
>> -	unsigned int hw_q, queue_mask, q, num_queues;
>> +	unsigned int hw_q, q;
>>  	struct macb *bp = netdev_priv(dev);
>>  	struct macb_queue *queue;
>>  	int err;
>> @@ -2226,10 +2226,8 @@ static int macb_init(struct platform_device *pdev)
>>  	 * register mapping but we don't want to test the queue index then
>>  	 * compute the corresponding register offset at run time.
>>  	 */
>> -	macb_probe_queues(bp->regs, &queue_mask, &num_queues);
>> -
>> -	for (hw_q = 0, q = 0; hw_q < MACB_MAX_QUEUES; ++hw_q) {
>> -		if (!(queue_mask & (1 << hw_q)))
>> +	for (hw_q = 0, q = 0; hw_q < bp->num_queues; ++hw_q) {
>> +		if (!(bp->queue_mask & (1 << hw_q)))
>>  			continue;
> 
> The exit condition of the for loop must remain "hw_q < MACB_MAX_QUEUES" and 
> should not be replaced by "hw_q < bp->num_queues".
> Indeed there can be only 2 queues, for instance queue0 and queue7. So if you
> change the exit conditon of the loop, queue7 won't be initialized and HRESP 
> errors will occur.

Absolutely. Sorry to have misunderstood this condition.

I'll re-spin a v2 series.

Bye,

>>  
>>  		queue = &bp->queues[q];
>> @@ -2715,6 +2713,7 @@ static int macb_probe(struct platform_device *pdev)
>>  	bp->dev = dev;
>>  	bp->regs = mem;
>>  	bp->num_queues = num_queues;
>> +	bp->queue_mask = queue_mask;
>>  	spin_lock_init(&bp->lock);
>>  
>>  	platform_set_drvdata(pdev, dev);
>> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
>> index bc6e35c40822..0b6afac91bfe 100644
>> --- a/drivers/net/ethernet/cadence/macb.h
>> +++ b/drivers/net/ethernet/cadence/macb.h
>> @@ -785,6 +785,7 @@ struct macb {
>>  	size_t			rx_buffer_size;
>>  
>>  	unsigned int		num_queues;
>> +	unsigned int		queue_mask;
>>  	struct macb_queue	queues[MACB_MAX_QUEUES];
>>  
>>  	spinlock_t		lock;
>>
> 
> Best Regards,
> 
> Cyrille
> 

-- 
Nicolas Ferre