usb: dwc3: gadget: allocate 3 packets for bulk and isoc endpoints
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@ti.com>
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 1f64e7c..c30ab6d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -172,6 +172,7 @@
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 @@
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 have enough
+ * space available on the FIFO RAM for all possible use cases.
+ * 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
+ */
+ tmp = mult * (dep->endpoint.maxpacket + mdwidth);
tmp += mdwidth;
fifo_size = DIV_ROUND_UP(tmp, mdwidth);
+
fifo_size |= (last_fifo_depth << 16);
dev_vdbg(dwc->dev, "%s: Fifo Addr %04x Size %d\n",