diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c index 79dc611a2fc46b5427ecb60bd5f5357fd4cee0a5..fb1fe96d3215335c1df7afe17b2b3ef3763d0d93 100644 --- a/drivers/usb/gadget/function/f_midi.c +++ b/drivers/usb/gadget/function/f_midi.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include @@ -88,6 +89,9 @@ struct f_midi { int index; char *id; unsigned int buflen, qlen; + /* This fifo is used as a buffer ring for pre-allocated IN usb_requests */ + DECLARE_KFIFO_PTR(in_req_fifo, struct usb_request *); + unsigned int in_last_port; }; static inline struct f_midi *func_to_midi(struct usb_function *f) @@ -95,7 +99,7 @@ static inline struct f_midi *func_to_midi(struct usb_function *f) return container_of(f, struct f_midi, func); } -static void f_midi_transmit(struct f_midi *midi, struct usb_request *req); +static void f_midi_transmit(struct f_midi *midi); DECLARE_UAC_AC_HEADER_DESCRIPTOR(1); DECLARE_USB_MIDI_OUT_JACK_DESCRIPTOR(1); @@ -253,7 +257,8 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req) } else if (ep == midi->in_ep) { /* Our transmit completed. See if there's more to go. * f_midi_transmit eats req, don't queue it again. */ - f_midi_transmit(midi, req); + req->length = 0; + f_midi_transmit(midi); return; } break; @@ -264,10 +269,12 @@ f_midi_complete(struct usb_ep *ep, struct usb_request *req) case -ESHUTDOWN: /* disconnect from host */ VDBG(cdev, "%s gone (%d), %d/%d\n", ep->name, status, req->actual, req->length); - if (ep == midi->out_ep) + if (ep == midi->out_ep) { f_midi_handle_out_data(ep, req); - - free_ep_req(ep, req); + /* We don't need to free IN requests because it's handled + * by the midi->in_req_fifo. */ + free_ep_req(ep, req); + } return; case -EOVERFLOW: /* buffer overrun on read means that @@ -334,6 +341,20 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt) if (err) return err; + /* pre-allocate write usb requests to use on f_midi_transmit. */ + while (kfifo_avail(&midi->in_req_fifo)) { + struct usb_request *req = + midi_alloc_ep_req(midi->in_ep, midi->buflen); + + if (req == NULL) + return -ENOMEM; + + req->length = 0; + req->complete = f_midi_complete; + + kfifo_put(&midi->in_req_fifo, req); + } + /* allocate a bunch of read buffers and queue them all at once. */ for (i = 0; i < midi->qlen && err == 0; i++) { struct usb_request *req = @@ -358,6 +379,7 @@ static void f_midi_disable(struct usb_function *f) { struct f_midi *midi = func_to_midi(f); struct usb_composite_dev *cdev = f->config->cdev; + struct usb_request *req = NULL; DBG(cdev, "disable\n"); @@ -367,6 +389,10 @@ static void f_midi_disable(struct usb_function *f) */ usb_ep_disable(midi->in_ep); usb_ep_disable(midi->out_ep); + + /* release IN requests */ + while (kfifo_get(&midi->in_req_fifo, &req)) + free_ep_req(midi->in_ep, req); } static int f_midi_snd_free(struct snd_device *device) @@ -488,57 +514,113 @@ static void f_midi_transmit_byte(struct usb_request *req, } } -static void f_midi_transmit(struct f_midi *midi, struct usb_request *req) +static void f_midi_drop_out_substreams(struct f_midi *midi) { - struct usb_ep *ep = midi->in_ep; - int i; - - if (!ep) - return; - - if (!req) - req = midi_alloc_ep_req(ep, midi->buflen); - - if (!req) { - ERROR(midi, "%s: alloc_ep_request failed\n", __func__); - return; - } - req->length = 0; - req->complete = f_midi_complete; + unsigned int i; for (i = 0; i < MAX_PORTS; i++) { struct gmidi_in_port *port = midi->in_port[i]; struct snd_rawmidi_substream *substream = midi->in_substream[i]; - if (!port || !port->active || !substream) + if (!port) + break; + + if (!port->active || !substream) continue; - while (req->length + 3 < midi->buflen) { - uint8_t b; - if (snd_rawmidi_transmit(substream, &b, 1) != 1) { - port->active = 0; + snd_rawmidi_drop_output(substream); + } +} + +static void f_midi_transmit(struct f_midi *midi) +{ + struct usb_ep *ep = midi->in_ep; + bool active; + + /* We only care about USB requests if IN endpoint is enabled */ + if (!ep || !ep->enabled) + goto drop_out; + + do { + struct usb_request *req = NULL; + unsigned int len, i; + + active = false; + + /* We peek the request in order to reuse it if it fails + * to enqueue on its endpoint */ + len = kfifo_peek(&midi->in_req_fifo, &req); + if (len != 1) { + ERROR(midi, "%s: Couldn't get usb request\n", __func__); + goto drop_out; + } + + /* If buffer overrun, then we ignore this transmission. + * IMPORTANT: This will cause the user-space rawmidi device to block until a) usb + * requests have been completed or b) snd_rawmidi_write() times out. */ + if (req->length > 0) + return; + + for (i = midi->in_last_port; i < MAX_PORTS; i++) { + struct gmidi_in_port *port = midi->in_port[i]; + struct snd_rawmidi_substream *substream = midi->in_substream[i]; + + if (!port) { + /* Reset counter when we reach the last available port */ + midi->in_last_port = 0; + break; + } + + if (!port->active || !substream) + continue; + + while (req->length + 3 < midi->buflen) { + uint8_t b; + + if (snd_rawmidi_transmit(substream, &b, 1) != 1) { + port->active = 0; + break; + } + f_midi_transmit_byte(req, port, b); + } + + active = !!port->active; + /* Check if last port is still active, which means that + * there is still data on that substream but this current + * request run out of space. */ + if (active) { + midi->in_last_port = i; + /* There is no need to re-iterate though midi ports. */ break; } - f_midi_transmit_byte(req, port, b); } - } - if (req->length > 0 && ep->enabled) { - int err; + if (req->length > 0) { + int err; - err = usb_ep_queue(ep, req, GFP_ATOMIC); - if (err < 0) - ERROR(midi, "%s queue req: %d\n", - midi->in_ep->name, err); - } else { - free_ep_req(ep, req); - } + err = usb_ep_queue(ep, req, GFP_ATOMIC); + if (err < 0) { + ERROR(midi, "%s failed to queue req: %d\n", + midi->in_ep->name, err); + req->length = 0; /* Re-use request next time. */ + } else { + /* Upon success, put request at the back of the queue. */ + kfifo_skip(&midi->in_req_fifo); + kfifo_put(&midi->in_req_fifo, req); + } + } + } while (active); + + return; + +drop_out: + f_midi_drop_out_substreams(midi); } static void f_midi_in_tasklet(unsigned long data) { struct f_midi *midi = (struct f_midi *) data; - f_midi_transmit(midi, NULL); + f_midi_transmit(midi); } static int f_midi_in_open(struct snd_rawmidi_substream *substream) @@ -664,6 +746,7 @@ static int f_midi_register_card(struct f_midi *midi) goto fail; } midi->rmidi = rmidi; + midi->in_last_port = 0; strcpy(rmidi->name, card->shortname); rmidi->info_flags = SNDRV_RAWMIDI_INFO_OUTPUT | SNDRV_RAWMIDI_INFO_INPUT | @@ -1053,6 +1136,7 @@ static void f_midi_free(struct usb_function *f) mutex_lock(&opts->lock); for (i = opts->in_ports - 1; i >= 0; --i) kfree(midi->in_port[i]); + kfifo_free(&midi->in_req_fifo); kfree(midi); --opts->refcnt; mutex_unlock(&opts->lock); @@ -1126,6 +1210,12 @@ static struct usb_function *f_midi_alloc(struct usb_function_instance *fi) midi->index = opts->index; midi->buflen = opts->buflen; midi->qlen = opts->qlen; + midi->in_last_port = 0; + + status = kfifo_alloc(&midi->in_req_fifo, midi->qlen, GFP_KERNEL); + if (status) + goto setup_fail; + ++opts->refcnt; mutex_unlock(&opts->lock); diff --git a/drivers/usb/gadget/legacy/gmidi.c b/drivers/usb/gadget/legacy/gmidi.c index e27aad5e50b9af9b392a4e4fa2324fe91683dfa4..fc2ac150f5ffc4e15398a6d5a1a8d23f75baea53 100644 --- a/drivers/usb/gadget/legacy/gmidi.c +++ b/drivers/usb/gadget/legacy/gmidi.c @@ -53,7 +53,7 @@ MODULE_PARM_DESC(buflen, "MIDI buffer length"); static unsigned int qlen = 32; module_param(qlen, uint, S_IRUGO); -MODULE_PARM_DESC(qlen, "USB read request queue length"); +MODULE_PARM_DESC(qlen, "USB read and write request queue length"); static unsigned int in_ports = 1; module_param(in_ports, uint, S_IRUGO);