515 lines
13 KiB
C
515 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Virtual Raw MIDI client on Sequencer
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*
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* Copyright (c) 2000 by Takashi Iwai <tiwai@suse.de>,
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* Jaroslav Kysela <perex@perex.cz>
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*/
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/*
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* Virtual Raw MIDI client
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*
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* The virtual rawmidi client is a sequencer client which associate
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* a rawmidi device file. The created rawmidi device file can be
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* accessed as a normal raw midi, but its MIDI source and destination
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* are arbitrary. For example, a user-client software synth connected
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* to this port can be used as a normal midi device as well.
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*
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* The virtual rawmidi device accepts also multiple opens. Each file
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* has its own input buffer, so that no conflict would occur. The drain
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* of input/output buffer acts only to the local buffer.
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*
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*/
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#include <linux/init.h>
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#include <linux/wait.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <sound/core.h>
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#include <sound/rawmidi.h>
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#include <sound/info.h>
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#include <sound/control.h>
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#include <sound/minors.h>
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#include <sound/seq_kernel.h>
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#include <sound/seq_midi_event.h>
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#include <sound/seq_virmidi.h>
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MODULE_AUTHOR("Takashi Iwai <tiwai@suse.de>");
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MODULE_DESCRIPTION("Virtual Raw MIDI client on Sequencer");
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MODULE_LICENSE("GPL");
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/*
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* initialize an event record
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*/
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static void snd_virmidi_init_event(struct snd_virmidi *vmidi,
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struct snd_seq_event *ev)
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{
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memset(ev, 0, sizeof(*ev));
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ev->source.port = vmidi->port;
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switch (vmidi->seq_mode) {
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case SNDRV_VIRMIDI_SEQ_DISPATCH:
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ev->dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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break;
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case SNDRV_VIRMIDI_SEQ_ATTACH:
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/* FIXME: source and destination are same - not good.. */
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ev->dest.client = vmidi->client;
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ev->dest.port = vmidi->port;
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break;
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}
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ev->type = SNDRV_SEQ_EVENT_NONE;
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}
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/*
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* decode input event and put to read buffer of each opened file
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*/
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static int snd_virmidi_dev_receive_event(struct snd_virmidi_dev *rdev,
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struct snd_seq_event *ev,
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bool atomic)
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{
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struct snd_virmidi *vmidi;
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unsigned char msg[4];
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int len;
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if (atomic)
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read_lock(&rdev->filelist_lock);
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else
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down_read(&rdev->filelist_sem);
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list_for_each_entry(vmidi, &rdev->filelist, list) {
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if (!READ_ONCE(vmidi->trigger))
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continue;
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if (ev->type == SNDRV_SEQ_EVENT_SYSEX) {
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if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE)
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continue;
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snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)snd_rawmidi_receive, vmidi->substream);
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} else {
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len = snd_midi_event_decode(vmidi->parser, msg, sizeof(msg), ev);
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if (len > 0)
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snd_rawmidi_receive(vmidi->substream, msg, len);
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}
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}
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if (atomic)
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read_unlock(&rdev->filelist_lock);
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else
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up_read(&rdev->filelist_sem);
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return 0;
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}
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/*
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* event handler of virmidi port
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*/
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static int snd_virmidi_event_input(struct snd_seq_event *ev, int direct,
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void *private_data, int atomic, int hop)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!(rdev->flags & SNDRV_VIRMIDI_USE))
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return 0; /* ignored */
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return snd_virmidi_dev_receive_event(rdev, ev, atomic);
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}
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/*
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* trigger rawmidi stream for input
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*/
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static void snd_virmidi_input_trigger(struct snd_rawmidi_substream *substream, int up)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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WRITE_ONCE(vmidi->trigger, !!up);
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}
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/* process rawmidi bytes and send events;
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* we need no lock here for vmidi->event since it's handled only in this work
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*/
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static void snd_vmidi_output_work(struct work_struct *work)
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{
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struct snd_virmidi *vmidi;
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struct snd_rawmidi_substream *substream;
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unsigned char input;
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int ret;
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vmidi = container_of(work, struct snd_virmidi, output_work);
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substream = vmidi->substream;
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/* discard the outputs in dispatch mode unless subscribed */
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if (vmidi->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH &&
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!(vmidi->rdev->flags & SNDRV_VIRMIDI_SUBSCRIBE)) {
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snd_rawmidi_proceed(substream);
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return;
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}
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while (READ_ONCE(vmidi->trigger)) {
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if (snd_rawmidi_transmit(substream, &input, 1) != 1)
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break;
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if (!snd_midi_event_encode_byte(vmidi->parser, input,
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&vmidi->event))
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continue;
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if (vmidi->event.type != SNDRV_SEQ_EVENT_NONE) {
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ret = snd_seq_kernel_client_dispatch(vmidi->client,
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&vmidi->event,
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false, 0);
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vmidi->event.type = SNDRV_SEQ_EVENT_NONE;
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if (ret < 0)
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break;
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}
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/* rawmidi input might be huge, allow to have a break */
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cond_resched();
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}
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}
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/*
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* trigger rawmidi stream for output
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*/
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static void snd_virmidi_output_trigger(struct snd_rawmidi_substream *substream, int up)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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WRITE_ONCE(vmidi->trigger, !!up);
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if (up)
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queue_work(system_highpri_wq, &vmidi->output_work);
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}
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/*
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* open rawmidi handle for input
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*/
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static int snd_virmidi_input_open(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_rawmidi_runtime *runtime = substream->runtime;
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struct snd_virmidi *vmidi;
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vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
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if (vmidi == NULL)
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return -ENOMEM;
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vmidi->substream = substream;
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if (snd_midi_event_new(0, &vmidi->parser) < 0) {
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kfree(vmidi);
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return -ENOMEM;
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}
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vmidi->seq_mode = rdev->seq_mode;
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vmidi->client = rdev->client;
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vmidi->port = rdev->port;
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runtime->private_data = vmidi;
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down_write(&rdev->filelist_sem);
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write_lock_irq(&rdev->filelist_lock);
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list_add_tail(&vmidi->list, &rdev->filelist);
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write_unlock_irq(&rdev->filelist_lock);
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up_write(&rdev->filelist_sem);
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vmidi->rdev = rdev;
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return 0;
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}
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/*
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* open rawmidi handle for output
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*/
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static int snd_virmidi_output_open(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_rawmidi_runtime *runtime = substream->runtime;
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struct snd_virmidi *vmidi;
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vmidi = kzalloc(sizeof(*vmidi), GFP_KERNEL);
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if (vmidi == NULL)
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return -ENOMEM;
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vmidi->substream = substream;
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if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &vmidi->parser) < 0) {
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kfree(vmidi);
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return -ENOMEM;
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}
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vmidi->seq_mode = rdev->seq_mode;
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vmidi->client = rdev->client;
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vmidi->port = rdev->port;
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snd_virmidi_init_event(vmidi, &vmidi->event);
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vmidi->rdev = rdev;
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INIT_WORK(&vmidi->output_work, snd_vmidi_output_work);
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runtime->private_data = vmidi;
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return 0;
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}
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/*
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* close rawmidi handle for input
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*/
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static int snd_virmidi_input_close(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi_dev *rdev = substream->rmidi->private_data;
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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down_write(&rdev->filelist_sem);
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write_lock_irq(&rdev->filelist_lock);
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list_del(&vmidi->list);
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write_unlock_irq(&rdev->filelist_lock);
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up_write(&rdev->filelist_sem);
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snd_midi_event_free(vmidi->parser);
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substream->runtime->private_data = NULL;
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kfree(vmidi);
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return 0;
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}
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/*
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* close rawmidi handle for output
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*/
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static int snd_virmidi_output_close(struct snd_rawmidi_substream *substream)
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{
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struct snd_virmidi *vmidi = substream->runtime->private_data;
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WRITE_ONCE(vmidi->trigger, false); /* to be sure */
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cancel_work_sync(&vmidi->output_work);
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snd_midi_event_free(vmidi->parser);
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substream->runtime->private_data = NULL;
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kfree(vmidi);
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return 0;
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}
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/*
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* subscribe callback - allow output to rawmidi device
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*/
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static int snd_virmidi_subscribe(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!try_module_get(rdev->card->module))
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return -EFAULT;
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rdev->flags |= SNDRV_VIRMIDI_SUBSCRIBE;
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return 0;
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}
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/*
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* unsubscribe callback - disallow output to rawmidi device
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*/
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static int snd_virmidi_unsubscribe(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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rdev->flags &= ~SNDRV_VIRMIDI_SUBSCRIBE;
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module_put(rdev->card->module);
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return 0;
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}
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/*
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* use callback - allow input to rawmidi device
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*/
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static int snd_virmidi_use(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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if (!try_module_get(rdev->card->module))
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return -EFAULT;
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rdev->flags |= SNDRV_VIRMIDI_USE;
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return 0;
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}
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/*
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* unuse callback - disallow input to rawmidi device
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*/
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static int snd_virmidi_unuse(void *private_data,
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struct snd_seq_port_subscribe *info)
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{
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struct snd_virmidi_dev *rdev;
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rdev = private_data;
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rdev->flags &= ~SNDRV_VIRMIDI_USE;
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module_put(rdev->card->module);
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return 0;
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}
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/*
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* Register functions
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*/
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static const struct snd_rawmidi_ops snd_virmidi_input_ops = {
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.open = snd_virmidi_input_open,
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.close = snd_virmidi_input_close,
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.trigger = snd_virmidi_input_trigger,
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};
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static const struct snd_rawmidi_ops snd_virmidi_output_ops = {
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.open = snd_virmidi_output_open,
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.close = snd_virmidi_output_close,
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.trigger = snd_virmidi_output_trigger,
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};
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/*
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* create a sequencer client and a port
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*/
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static int snd_virmidi_dev_attach_seq(struct snd_virmidi_dev *rdev)
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{
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int client;
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struct snd_seq_port_callback pcallbacks;
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struct snd_seq_port_info *pinfo;
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int err;
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if (rdev->client >= 0)
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return 0;
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pinfo = kzalloc(sizeof(*pinfo), GFP_KERNEL);
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if (!pinfo) {
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err = -ENOMEM;
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goto __error;
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}
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client = snd_seq_create_kernel_client(rdev->card, rdev->device,
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"%s %d-%d", rdev->rmidi->name,
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rdev->card->number,
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rdev->device);
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if (client < 0) {
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err = client;
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goto __error;
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}
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rdev->client = client;
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/* create a port */
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pinfo->addr.client = client;
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sprintf(pinfo->name, "VirMIDI %d-%d", rdev->card->number, rdev->device);
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/* set all capabilities */
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
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pinfo->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
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pinfo->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
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| SNDRV_SEQ_PORT_TYPE_SOFTWARE
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| SNDRV_SEQ_PORT_TYPE_PORT;
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pinfo->midi_channels = 16;
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memset(&pcallbacks, 0, sizeof(pcallbacks));
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pcallbacks.owner = THIS_MODULE;
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pcallbacks.private_data = rdev;
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pcallbacks.subscribe = snd_virmidi_subscribe;
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pcallbacks.unsubscribe = snd_virmidi_unsubscribe;
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pcallbacks.use = snd_virmidi_use;
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pcallbacks.unuse = snd_virmidi_unuse;
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pcallbacks.event_input = snd_virmidi_event_input;
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pinfo->kernel = &pcallbacks;
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err = snd_seq_kernel_client_ctl(client, SNDRV_SEQ_IOCTL_CREATE_PORT, pinfo);
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if (err < 0) {
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snd_seq_delete_kernel_client(client);
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rdev->client = -1;
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goto __error;
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}
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rdev->port = pinfo->addr.port;
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err = 0; /* success */
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__error:
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kfree(pinfo);
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return err;
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}
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/*
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* release the sequencer client
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*/
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static void snd_virmidi_dev_detach_seq(struct snd_virmidi_dev *rdev)
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{
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if (rdev->client >= 0) {
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snd_seq_delete_kernel_client(rdev->client);
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rdev->client = -1;
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}
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}
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/*
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* register the device
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*/
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static int snd_virmidi_dev_register(struct snd_rawmidi *rmidi)
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{
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struct snd_virmidi_dev *rdev = rmidi->private_data;
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int err;
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switch (rdev->seq_mode) {
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case SNDRV_VIRMIDI_SEQ_DISPATCH:
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err = snd_virmidi_dev_attach_seq(rdev);
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if (err < 0)
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return err;
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break;
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case SNDRV_VIRMIDI_SEQ_ATTACH:
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if (rdev->client == 0)
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return -EINVAL;
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/* should check presence of port more strictly.. */
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break;
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default:
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pr_err("ALSA: seq_virmidi: seq_mode is not set: %d\n", rdev->seq_mode);
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return -EINVAL;
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}
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return 0;
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}
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/*
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* unregister the device
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*/
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static int snd_virmidi_dev_unregister(struct snd_rawmidi *rmidi)
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{
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struct snd_virmidi_dev *rdev = rmidi->private_data;
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if (rdev->seq_mode == SNDRV_VIRMIDI_SEQ_DISPATCH)
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snd_virmidi_dev_detach_seq(rdev);
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return 0;
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}
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/*
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*
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*/
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static const struct snd_rawmidi_global_ops snd_virmidi_global_ops = {
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.dev_register = snd_virmidi_dev_register,
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.dev_unregister = snd_virmidi_dev_unregister,
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};
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/*
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* free device
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*/
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static void snd_virmidi_free(struct snd_rawmidi *rmidi)
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{
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struct snd_virmidi_dev *rdev = rmidi->private_data;
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kfree(rdev);
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}
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/*
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* create a new device
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*
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*/
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/* exported */
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int snd_virmidi_new(struct snd_card *card, int device, struct snd_rawmidi **rrmidi)
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{
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struct snd_rawmidi *rmidi;
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struct snd_virmidi_dev *rdev;
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int err;
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*rrmidi = NULL;
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if ((err = snd_rawmidi_new(card, "VirMidi", device,
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16, /* may be configurable */
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16, /* may be configurable */
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&rmidi)) < 0)
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return err;
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strcpy(rmidi->name, rmidi->id);
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rdev = kzalloc(sizeof(*rdev), GFP_KERNEL);
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if (rdev == NULL) {
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snd_device_free(card, rmidi);
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return -ENOMEM;
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}
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rdev->card = card;
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rdev->rmidi = rmidi;
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rdev->device = device;
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rdev->client = -1;
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init_rwsem(&rdev->filelist_sem);
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rwlock_init(&rdev->filelist_lock);
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INIT_LIST_HEAD(&rdev->filelist);
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rdev->seq_mode = SNDRV_VIRMIDI_SEQ_DISPATCH;
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rmidi->private_data = rdev;
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|
rmidi->private_free = snd_virmidi_free;
|
|
rmidi->ops = &snd_virmidi_global_ops;
|
|
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops);
|
|
snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops);
|
|
rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT |
|
|
SNDRV_RAWMIDI_INFO_OUTPUT |
|
|
SNDRV_RAWMIDI_INFO_DUPLEX;
|
|
*rrmidi = rmidi;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(snd_virmidi_new);
|