Commit 5cd8c48d authored May 16, 2014 by Zhuang Jin Can Committed by Felipe Balbi Jun 19, 2014

usb: dwc3: gadget: check link trb after free_slot is increased



In ISOC transfers, when free_slot points to the last TRB (i.e. Link
TRB), and all queued requests meet Missed Interval Isoc error, busy_slot
points to trb0.
	busy_slot->trb0
		   trb1
		   ...
	free_slot->trb31(Link TRB)

After end transfer and receiving the XferNotReady event, trb_left is
caculated as 1 which is wrong, and no TRB will be primed to the
endpoint.

The root cause is free_slot is not increased the same way as busy_slot.
When busy_slot is increased by one, it checks if points to a link TRB
after increasement, but free_slot checks it before increasement.
free_slot should behave the same as busy_slot to make the trb_left
caculation correct.

Reviewed-by: Pratyush Anand <pratyush.anand@st.com>
Signed-off-by: Zhuang Jin Can <jin.can.zhuang@intel.com>
Signed-off-by: Jiebing Li <jiebing.li@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

parent 7171511e

drivers/usb/dwc3/gadget.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -828,10 +828,6 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
		length, last ? " last" : "",
		chain ? " chain" : "");

		/* Skip the LINK-TRB on ISOC */
		if (((dep->free_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) &&
		usb_endpoint_xfer_isoc(dep->endpoint.desc))
		dep->free_slot++;

		trb = &dep->trb_pool[dep->free_slot & DWC3_TRB_MASK];

		@@ -843,6 +839,10 @@ static void dwc3_prepare_one_trb(struct dwc3_ep *dep,
		}

		dep->free_slot++;
		/* Skip the LINK-TRB on ISOC */
		if (((dep->free_slot & DWC3_TRB_MASK) == DWC3_TRB_NUM - 1) &&
		usb_endpoint_xfer_isoc(dep->endpoint.desc))
		dep->free_slot++;

		trb->size = DWC3_TRB_SIZE_LENGTH(length);
		trb->bpl = lower_32_bits(dma);