It turned out that current dwc3 gadget code is preparing multiple TRBs
for a transfer. Unfortunately, when multiple requests are in the same
queue, only for the last one the LST (last) ctrl bit is set.
Due to that dwc3 HW executes all TRBs up till the one marked as last.
Unfortunately, UMS requires call of ->complete callback after any send TRB.
This is the reason for "hangs" in executing UMS.
This code simplifies this situation and set each TRB's ctrl field bit to be
last (LST bit).
Signed-off-by: Lukasz Majewski <l.majew...@samsung.com>
---
drivers/usb/dwc3/gadget.c | 15 ++-------------
1 file changed, 2 insertions(+), 13 deletions(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d5dc70c..0c7082c 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -787,7 +787,6 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool
starting)
struct dwc3_request *req, *n;
u32 trbs_left;
u32 max;
- unsigned int last_one = 0;
BUILD_BUG_ON_NOT_POWER_OF_2(DWC3_TRB_NUM);
@@ -837,24 +836,14 @@ static void dwc3_prepare_trbs(struct dwc3_ep *dep, bool
starting)
list_for_each_entry_safe(req, n, &dep->request_list, list) {
unsigned length;
dma_addr_t dma;
- last_one = false;
dma = req->request.dma;
length = req->request.length;
- trbs_left--;
-
- if (!trbs_left)
- last_one = 1;
-
- /* Is this the last request? */
- if (list_is_last(&req->list, &dep->request_list))
- last_one = 1;
dwc3_prepare_one_trb(dep, req, dma, length,
- last_one, false, 0);
+ true, false, 0);
- if (last_one)
- break;
+ break;
}
}
--
2.0.0.rc2
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