> -----Original Message----- > From: linux-usb-owner@xxxxxxxxxxxxxxx [mailto:linux-usb-owner@xxxxxxxxxxxxxxx] On Behalf Of Felipe Balbi > Sent: Monday, February 06, 2012 6:26 AM > > Those transfer types are generally high bandwidth, so we > want to optimize transfers with those endpoints. > > For that, databook suggests allocating 3 * wMaxPacketSize > of FIFO. Let's do that. > > Signed-off-by: Felipe Balbi <balbi@xxxxxx> > --- > > This will be sent to v3.4 merge window, unless someone > has any concerns. Hi Felipe, I have concerns :) > drivers/usb/dwc3/gadget.c | 20 ++++++++++++++++++-- > 1 files changed, 18 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > index 1f64e7c..0542b96 100644 > --- a/drivers/usb/dwc3/gadget.c > +++ b/drivers/usb/dwc3/gadget.c > @@ -172,6 +172,7 @@ int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc) > for (num = 0; num < DWC3_ENDPOINTS_NUM; num++) { > struct dwc3_ep *dep = dwc->eps[num]; > int fifo_number = dep->number >> 1; > + int mult = 1; > int tmp; > > if (!(dep->number & 1)) > @@ -180,11 +181,26 @@ int dwc3_gadget_resize_tx_fifos(struct dwc3 *dwc) > if (!(dep->flags & DWC3_EP_ENABLED)) > continue; > > - tmp = dep->endpoint.maxpacket; > - tmp += mdwidth; > + if (usb_endpoint_xfer_bulk(dep->desc) > + || usb_endpoint_xfer_isoc(dep->desc)) > + mult = 3; > + > + /* > + * REVISIT: the following assumes we will always enough space > + * available on the FIFO RAM for all possible usecases. Make > + * sure that's true somehow and change FIFO allocation > + * accordingly. > + * > + * If we have Bulk or Isochronous endpoints, we want > + * them to be able to be very, very fast. So we're giving > + * those endpoints a fifo_size which is enough for 3 full > + * packets > + */ This breaks the HAPS platform, and any other platform which doesn't have enough FIFO RAM to support this. I really think you must implement this properly (checking for enough RAM) before you add it to the driver. But I really think trying to do things like this automatically in the driver is misguided. This should be part of platform data or device tree instead, IMHO. -- Paul -- 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
