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515 lines
13 KiB
515 lines
13 KiB
// 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 <[email protected]>, |
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* Jaroslav Kysela <[email protected]> |
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*/ |
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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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|
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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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|
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MODULE_AUTHOR("Takashi Iwai <[email protected]>"); |
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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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/* |
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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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/* |
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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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snd_midi_event_reset_decode(vmidi->parser); |
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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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/* |
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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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|
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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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|
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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; |
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rmidi->ops = &snd_virmidi_global_ops; |
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snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT, &snd_virmidi_input_ops); |
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snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT, &snd_virmidi_output_ops); |
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rmidi->info_flags = SNDRV_RAWMIDI_INFO_INPUT | |
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SNDRV_RAWMIDI_INFO_OUTPUT | |
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SNDRV_RAWMIDI_INFO_DUPLEX; |
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*rrmidi = rmidi; |
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return 0; |
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} |
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EXPORT_SYMBOL(snd_virmidi_new);
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