usb: ci_udc: parse QTD before over-writing it

ci_udc only allocates a single QTD structure per EP. All data needs to be
extracted from the DTD prior to calling ci_ep_submit_next_request(), since
that fills the QTD with next transaction's parameters. Fix
handle_ep_complete() to extract the transaction (remaining) length before
kicking off the next transaction.

In practice, this only causes writes to UMS devices to fail for me. I may
have tested the final versions of my previous ci_udc patch only with
reads. More recently, I had patches applied locally that allocated a QTD
per USB request rather than per USB EP, although since that doesn't give
any performance benefit, I'm dropping those.

Fixes: 2813006fecda ("usb: ci_udc: allow multiple buffer allocs per ep")
Signed-off-by: Stephen Warren <swarren@nvidia.com>

diff --git a/drivers/usb/gadget/ci_udc.c b/drivers/usb/gadget/ci_udc.c
index 290863d61fc96e59aea364ee6a5835ca8665b2a1..9cd003636a4499ba57637f37f9e8fdeed709340f 100644 (file)
--- a/drivers/usb/gadget/ci_udc.c
+++ b/drivers/usb/gadget/ci_udc.c
@@ -424,6 +424,7 @@ static void handle_ep_complete(struct ci_ep *ep)
        item = ci_get_qtd(num, in);
        ci_invalidate_qtd(num);
 
+       len = (item->info >> 16) & 0x7fff;
        if (item->info & 0xff)
                printf("EP%d/%s FAIL info=%x pg0=%x\n",
                       num, in ? "in" : "out", item->info, item->page0);
@@ -435,7 +436,6 @@ static void handle_ep_complete(struct ci_ep *ep)
        if (!list_empty(&ep->queue))
                ci_ep_submit_next_request(ep);
 
-       len = (item->info >> 16) & 0x7fff;
        ci_req->req.actual = ci_req->req.length - len;
        ci_debounce(ci_req, in);