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Date: Tue, 22 Sep 2015 18:54:58 +0200
From: Krzysztof Opasiak <k.opasiak@...sung.com>
To: balbi@...com, gregkh@...uxfoundation.org
Cc: linux-kernel@...r.kernel.org, andrzej.p@...sung.com,
stable@...r.kernel.org, Krzysztof Opasiak <k.opasiak@...sung.com>
Subject: [PATCH v2 2/2] usb: gadget: loopback: Fix looping back logic
implementation
Since:
commit e0857ce58e8658657f5f12fe25272b93cfeb16aa
("usb: gadget: loopback: don't queue requests to bogus endpoints")
Loopback function is not realy working as that commit removed
all looping back logic. After that commit ep-out works like
/dev/null and ep-in works like /dev/zero.
This commit fix this issue by allocating set of out requests
and set of in requests but each out req shares buffer with
one in req:
out_req->buf ---> buf <--- in_req.buf
out_req->context <---> in_req.context
The completion routine simply enqueue the suitable req in
an oposite direction.
Cc: <stable@...r.kernel.org> # 3.18+
Signed-off-by: Krzysztof Opasiak <k.opasiak@...sung.com>
---
Changes since v1:
- add missing usb_ep_free_request() in complete() callback
---
drivers/usb/gadget/function/f_loopback.c | 131 +++++++++++++++++++++---------
1 file changed, 92 insertions(+), 39 deletions(-)
diff --git a/drivers/usb/gadget/function/f_loopback.c b/drivers/usb/gadget/function/f_loopback.c
index e4bfed4..e60b4a3 100644
--- a/drivers/usb/gadget/function/f_loopback.c
+++ b/drivers/usb/gadget/function/f_loopback.c
@@ -245,22 +245,38 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
int status = req->status;
switch (status) {
-
case 0: /* normal completion? */
if (ep == loop->out_ep) {
- req->zero = (req->actual < req->length);
- req->length = req->actual;
+ /*
+ * We received some data from the host so let's
+ * queue it so host can read the from our in ep
+ */
+ struct usb_request *in_req = req->context;
+
+ in_req->zero = (req->actual < req->length);
+ in_req->length = req->actual;
+ ep = loop->in_ep;
+ req = in_req;
+ } else {
+ /*
+ * We have just looped back a bunch of data
+ * to host. Now let's wait for some more data.
+ */
+ req = req->context;
+ ep = loop->out_ep;
}
- /* queue the buffer for some later OUT packet */
- req->length = loop->buflen;
+ /* queue the buffer back to host or for next bunch of data */
status = usb_ep_queue(ep, req, GFP_ATOMIC);
- if (status == 0)
+ if (status == 0) {
return;
+ } else {
+ ERROR(cdev, "Unable to loop back buffer to %s: %d\n",
+ ep->name, status);
+ goto free_req;
+ }
/* "should never get here" */
- /* FALLTHROUGH */
-
default:
ERROR(cdev, "%s loop complete --> %d, %d/%d\n", ep->name,
status, req->actual, req->length);
@@ -274,6 +290,10 @@ static void loopback_complete(struct usb_ep *ep, struct usb_request *req)
case -ECONNABORTED: /* hardware forced ep reset */
case -ECONNRESET: /* request dequeued */
case -ESHUTDOWN: /* disconnect from host */
+free_req:
+ usb_ep_free_request(ep == loop->in_ep ?
+ loop->out_ep : loop->in_ep,
+ req->context);
free_ep_req(ep, req);
return;
}
@@ -295,50 +315,72 @@ static inline struct usb_request *lb_alloc_ep_req(struct usb_ep *ep, int len)
return alloc_ep_req(ep, len, loop->buflen);
}
-static int enable_endpoint(struct usb_composite_dev *cdev, struct f_loopback *loop,
- struct usb_ep *ep)
+static int alloc_requests(struct usb_composite_dev *cdev,
+ struct f_loopback *loop)
{
- struct usb_request *req;
- unsigned i;
- int result;
-
- /*
- * one endpoint writes data back IN to the host while another endpoint
- * just reads OUT packets
- */
- result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
- if (result)
- goto fail0;
- result = usb_ep_enable(ep);
- if (result < 0)
- goto fail0;
- ep->driver_data = loop;
+ struct usb_request *in_req, *out_req;
+ int i;
+ int result = 0;
/*
* allocate a bunch of read buffers and queue them all at once.
- * we buffer at most 'qlen' transfers; fewer if any need more
- * than 'buflen' bytes each.
+ * we buffer at most 'qlen' transfers; We allocate buffers only
+ * for out transfer and reuse them in IN transfers to implement
+ * our loopback functionality
*/
for (i = 0; i < loop->qlen && result == 0; i++) {
- req = lb_alloc_ep_req(ep, 0);
- if (!req)
- goto fail1;
+ result = -ENOMEM;
+
+ in_req = usb_ep_alloc_request(loop->in_ep, GFP_KERNEL);
+ if (!in_req)
+ goto fail;
+
+ out_req = lb_alloc_ep_req(loop->out_ep, 0);
+ if (!out_req)
+ goto fail_in;
+
+ in_req->complete = loopback_complete;
+ out_req->complete = loopback_complete;
+
+ in_req->buf = out_req->buf;
+ /* length will be set in complete routine */
+ in_req->context = out_req;
+ out_req->context = out_req;
- req->complete = loopback_complete;
- result = usb_ep_queue(ep, req, GFP_ATOMIC);
+ result = usb_ep_queue(loop->out_ep, out_req, GFP_ATOMIC);
if (result) {
ERROR(cdev, "%s queue req --> %d\n",
- ep->name, result);
- goto fail1;
+ loop->out_ep->name, result);
+ goto fail_out;
}
}
return 0;
-fail1:
- usb_ep_disable(ep);
+fail_out:
+ free_ep_req(loop->out_ep, out_req);
+fail_in:
+ usb_ep_free_request(loop->in_ep, in_req);
+fail:
+ return result;
+}
+
+static int enable_endpoint(struct usb_composite_dev *cdev,
+ struct f_loopback *loop, struct usb_ep *ep)
+{
+ int result;
+
+ result = config_ep_by_speed(cdev->gadget, &(loop->function), ep);
+ if (result)
+ goto out;
-fail0:
+ result = usb_ep_enable(ep);
+ if (result < 0)
+ goto out;
+ ep->driver_data = loop;
+ result = 0;
+
+out:
return result;
}
@@ -349,13 +391,24 @@ enable_loopback(struct usb_composite_dev *cdev, struct f_loopback *loop)
result = enable_endpoint(cdev, loop, loop->in_ep);
if (result)
- return result;
+ goto out;
result = enable_endpoint(cdev, loop, loop->out_ep);
if (result)
- return result;
+ goto disable_in;
+
+ result = alloc_requests(cdev, loop);
+ if (result)
+ goto disable_out;
DBG(cdev, "%s enabled\n", loop->function.name);
+ return 0;
+
+disable_out:
+ usb_ep_disable(loop->out_ep);
+disable_in:
+ usb_ep_disable(loop->in_ep);
+out:
return result;
}
--
1.7.9.5
--
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