Re: [PATCH v9 7/8] usb: chipidea: udc: prepare qhead with dma_alloc_coherent

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On Mon, Apr 01, 2013 at 10:49:26AM +0800, Peter Chen wrote:
> On Fri, Mar 29, 2013 at 12:32:00AM +0100, Michael Grzeschik wrote:

[snip]

> What's the value of sizeof(struct ci13xxx_qh) after you pack it
> as 64 bytes aligned?
> 

With the struct attribute aligned(64) the result
of sizeof(struct ci13xxx_qh) is 64 bytes.

> QH is 48-bytes structure, but needs 64-bytes aligned, it can't
> avoid wasting 16 bytes. 
Correct.

> So, please make sure the memory layout is correct for qh arrays.

I tested the code, it did not work without the aligned attribute.

> >  	/* alloc resources */
> > -	ci->qh_pool = dma_pool_create("ci13xxx_qh", dev,
> > -				       sizeof(struct ci13xxx_qh),
> > -				       64, CI13XXX_PAGE_SIZE);
> > -	if (ci->qh_pool == NULL)
> > +	ci->qh.ptr = dma_alloc_coherent(dev, ci->qh.size,
> > +					&ci->qh.dma, GFP_ATOMIC);
> > +
> 
> GFP_ATMOIC isn't needed.

Correct, will fix.

> 
> > +	if (ci->qh.ptr == NULL)
> >  		return -ENOMEM;
> >  
> >  	ci->td_pool = dma_pool_create("ci13xxx_td", dev,
> > @@ -1814,7 +1814,6 @@ destroy_eps:
> >  free_pools:
> >  	dma_pool_destroy(ci->td_pool);
> >  free_qh_pool:
> > -	dma_pool_destroy(ci->qh_pool);
> 
> You may need dma_free_coherent.

Will add that here.

> 
> >  	return retval;
> >  }
> >  
> > @@ -1836,7 +1835,6 @@ static void udc_stop(struct ci13xxx *ci)
> >  	destroy_eps(ci);
> >  
> >  	dma_pool_destroy(ci->td_pool);
> > -	dma_pool_destroy(ci->qh_pool);
> >  
> >  	if (!IS_ERR_OR_NULL(ci->transceiver)) {
> >  		otg_set_peripheral(ci->transceiver->otg, NULL);
> > diff --git a/drivers/usb/chipidea/udc.h b/drivers/usb/chipidea/udc.h
> > index 4b1315a..b7d3882 100644
> > --- a/drivers/usb/chipidea/udc.h
> > +++ b/drivers/usb/chipidea/udc.h
> > @@ -55,7 +55,7 @@ struct ci13xxx_qh {
> >  	/* 9 */
> >  	u32 RESERVED;
> >  	struct usb_ctrlrequest   setup;
> > -} __attribute__ ((packed, aligned(4)));
> > +} __attribute__ ((packed, aligned(64)));
> >  
> >  /**
> >   * struct ci13xxx_req - usb request representation
> > -- 
> > 1.8.2.rc2

Thanks for the review,
Michael

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