Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752870Ab0BQRC0 (ORCPT ); Wed, 17 Feb 2010 12:02:26 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:46059 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752688Ab0BQRCY (ORCPT ); Wed, 17 Feb 2010 12:02:24 -0500 Date: Wed, 17 Feb 2010 12:02:21 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: "Shilimkar, Santosh" cc: Oliver Neukum , Russell King - ARM Linux , Catalin Marinas , Pavel Machek , Greg KH , Matthew Dharm , Sergei Shtylyov , Ming Lei , Sebastian Siewior , "linux-usb@vger.kernel.org" , linux-kernel , linux-arm-kernel , "Mankad, Maulik Ojas" , "Gadiyar, Anand" Subject: RE: USB mass storage and ARM cache coherency In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2128 Lines: 51 On Wed, 17 Feb 2010, Shilimkar, Santosh wrote: > How about below approach? Controller driver can set > "uses_pio_for_control" if it can't do dma for control transfer. > > diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c > index 80995ef..e3eae02 100644 > --- a/drivers/usb/core/hcd.c > +++ b/drivers/usb/core/hcd.c > @@ -1276,7 +1276,7 @@ static int map_urb_for_dma(struct usb_hcd *hcd, struct urb *urb, > > if (usb_endpoint_xfer_control(&urb->ep->desc) > && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) { > - if (hcd->self.uses_dma) { > + if (hcd->self.uses_dma && !hcd->self.uses_pio_for_control) { > urb->setup_dma = dma_map_single( > hcd->self.controller, > urb->setup_packet, > @@ -1335,7 +1335,7 @@ static void unmap_urb_for_dma(struct usb_hcd *hcd, struct urb *urb) > > if (usb_endpoint_xfer_control(&urb->ep->desc) > && !(urb->transfer_flags & URB_NO_SETUP_DMA_MAP)) { > - if (hcd->self.uses_dma) > + if (hcd->self.uses_dma && !hcd->self.uses_pio_for_control) > dma_unmap_single(hcd->self.controller, urb->setup_dma, > sizeof(struct usb_ctrlrequest), > DMA_TO_DEVICE); > diff --git a/include/linux/usb.h b/include/linux/usb.h > index d7ace1b..ba5b0a2 100644 > --- a/include/linux/usb.h > +++ b/include/linux/usb.h > @@ -329,6 +329,9 @@ struct usb_bus { > int busnum; /* Bus number (in order of reg) */ > const char *bus_name; /* stable id (PCI slot_name etc) */ > u8 uses_dma; /* Does the host controller use DMA? */ > + u8 uses_pio_for_control; /* Does the host controller use PIO > + * for control tansfers? > + */ > u8 otg_port; /* 0, or number of OTG/HNP port */ > unsigned is_b_host:1; /* true during some HNP roleswitches */ > unsigned b_hnp_enable:1; /* OTG: did A-Host enable HNP? */ Why do you skip mapping the setup packet but not the data packet? Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/