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-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
