> -----Original Message----- > From: Alan Stern [mailto:stern@xxxxxxxxxxxxxxxxxxx] > Sent: Tuesday, August 24, 2010 8:30 PM > To: Maulik Mankad > Cc: linux-usb@xxxxxxxxxxxxxxx; Felipe Balbi > Subject: Re: [PATCH V3] usb: musb: host: Unmap the buffer for PIO data > transfers > > On Tue, 24 Aug 2010, Maulik Mankad wrote: > > > The USB stack maps the buffer for DMA if the controller supports DMA. > > MUSB controller can perform DMA as well as PIO transfers. > > The buffer needs to be unmapped before CPU can perform > > PIO data transfers. > > > > Export unmap_urb_for_dma() so that drivers can perform > > the DMA unmapping in a sane way. > > > > Signed-off-by: Maulik Mankad <x0082077@xxxxxx> > > Cc: Felipe Balbi <felipe.balbi@xxxxxxxxx> > > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > > --- > > Based on 2.6.36-rc1 > > V3: Fix Alan's comments. > > drivers/usb/core/hcd.c | 3 ++- > > drivers/usb/musb/musb_host.c | 5 +++++ > > include/linux/usb/hcd.h | 1 + > > 3 files changed, 8 insertions(+), 1 deletion(-) > > > Index: mainline/include/linux/usb/hcd.h > > =================================================================== > > --- mainline.orig/include/linux/usb/hcd.h > > +++ mainline/include/linux/usb/hcd.h > > @@ -349,6 +349,7 @@ extern void usb_put_hcd(struct usb_hcd * > > extern int usb_add_hcd(struct usb_hcd *hcd, > > unsigned int irqnum, unsigned long irqflags); > > extern void usb_remove_hcd(struct usb_hcd *hcd); > > +extern void unmap_urb_for_dma(struct usb_hcd *, struct urb *); > > Hmm. Since this deals with an URB rather than with the host controller > itself, I would have put it just after usb_hcd_giveback_urb instead of > here. Apart from this one drawback, it looks okay to me. Ok will correct this. > > By the way, which URBs do you need to unmap in this way? Doesn't the > musb driver already tell the core not to map control URBs for DMA? > These are Bulk URB's. Thanks, Maulik -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
