From 91c42b0da8e353697c9b49fe541056c5d0518c49 Mon Sep 17 00:00:00 2001 From: Krzysztof Opasiak Date: Wed, 14 Oct 2015 22:49:40 +0200 Subject: [PATCH] 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: # 3.18+ Fixes: e0857ce58e8658657f5f12fe25272b93cfeb16aa ("usb: gadget: loopback: don't queue requests to bogus endpoints") Signed-off-by: Krzysztof Opasiak Signed-off-by: Felipe Balbi --- 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 79e284bba059..6b2102bc0699 100644 --- a/drivers/usb/gadget/function/f_loopback.c +++ b/drivers/usb/gadget/function/f_loopback.c @@ -243,22 +243,38 @@ 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); @@ -272,6 +288,10 @@ 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; } @@ -293,50 +313,72 @@ 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 = in_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; } @@ -347,13 +389,24 @@ 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; } -- 2.39.5