460 lines
13 KiB
C
460 lines
13 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Generic MIDI synth driver for ALSA sequencer
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* Copyright (c) 1998 by Frank van de Pol <fvdpol@coil.demon.nl>
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* Jaroslav Kysela <perex@perex.cz>
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*/
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/*
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Possible options for midisynth module:
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- automatic opening of midi ports on first received event or subscription
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(close will be performed when client leaves)
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*/
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/errno.h>
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#include <linux/string.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <sound/core.h>
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#include <sound/rawmidi.h>
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#include <sound/seq_kernel.h>
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#include <sound/seq_device.h>
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#include <sound/seq_midi_event.h>
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#include <sound/initval.h>
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MODULE_AUTHOR("Frank van de Pol <fvdpol@coil.demon.nl>, Jaroslav Kysela <perex@perex.cz>");
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MODULE_DESCRIPTION("Advanced Linux Sound Architecture sequencer MIDI synth.");
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MODULE_LICENSE("GPL");
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static int output_buffer_size = PAGE_SIZE;
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module_param(output_buffer_size, int, 0644);
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MODULE_PARM_DESC(output_buffer_size, "Output buffer size in bytes.");
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static int input_buffer_size = PAGE_SIZE;
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module_param(input_buffer_size, int, 0644);
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MODULE_PARM_DESC(input_buffer_size, "Input buffer size in bytes.");
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/* data for this midi synth driver */
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struct seq_midisynth {
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struct snd_card *card;
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int device;
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int subdevice;
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struct snd_rawmidi_file input_rfile;
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struct snd_rawmidi_file output_rfile;
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int seq_client;
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int seq_port;
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struct snd_midi_event *parser;
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};
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struct seq_midisynth_client {
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int seq_client;
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int num_ports;
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int ports_per_device[SNDRV_RAWMIDI_DEVICES];
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struct seq_midisynth *ports[SNDRV_RAWMIDI_DEVICES];
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};
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static struct seq_midisynth_client *synths[SNDRV_CARDS];
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static DEFINE_MUTEX(register_mutex);
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/* handle rawmidi input event (MIDI v1.0 stream) */
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static void snd_midi_input_event(struct snd_rawmidi_substream *substream)
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{
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struct snd_rawmidi_runtime *runtime;
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struct seq_midisynth *msynth;
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struct snd_seq_event ev;
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char buf[16], *pbuf;
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long res;
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if (substream == NULL)
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return;
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runtime = substream->runtime;
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msynth = runtime->private_data;
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if (msynth == NULL)
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return;
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memset(&ev, 0, sizeof(ev));
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while (runtime->avail > 0) {
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res = snd_rawmidi_kernel_read(substream, buf, sizeof(buf));
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if (res <= 0)
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continue;
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if (msynth->parser == NULL)
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continue;
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pbuf = buf;
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while (res-- > 0) {
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if (!snd_midi_event_encode_byte(msynth->parser,
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*pbuf++, &ev))
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continue;
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ev.source.port = msynth->seq_port;
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ev.dest.client = SNDRV_SEQ_ADDRESS_SUBSCRIBERS;
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snd_seq_kernel_client_dispatch(msynth->seq_client, &ev, 1, 0);
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/* clear event and reset header */
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memset(&ev, 0, sizeof(ev));
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}
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}
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}
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static int dump_midi(struct snd_rawmidi_substream *substream, const char *buf, int count)
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{
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struct snd_rawmidi_runtime *runtime;
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int tmp;
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if (snd_BUG_ON(!substream || !buf))
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return -EINVAL;
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runtime = substream->runtime;
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tmp = runtime->avail;
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if (tmp < count) {
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if (printk_ratelimit())
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pr_err("ALSA: seq_midi: MIDI output buffer overrun\n");
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return -ENOMEM;
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}
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if (snd_rawmidi_kernel_write(substream, buf, count) < count)
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return -EINVAL;
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return 0;
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}
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static int event_process_midi(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 seq_midisynth *msynth = private_data;
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unsigned char msg[10]; /* buffer for constructing midi messages */
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struct snd_rawmidi_substream *substream;
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int len;
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if (snd_BUG_ON(!msynth))
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return -EINVAL;
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substream = msynth->output_rfile.output;
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if (substream == NULL)
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return -ENODEV;
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if (ev->type == SNDRV_SEQ_EVENT_SYSEX) { /* special case, to save space */
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if ((ev->flags & SNDRV_SEQ_EVENT_LENGTH_MASK) != SNDRV_SEQ_EVENT_LENGTH_VARIABLE) {
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/* invalid event */
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pr_debug("ALSA: seq_midi: invalid sysex event flags = 0x%x\n", ev->flags);
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return 0;
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}
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snd_seq_dump_var_event(ev, (snd_seq_dump_func_t)dump_midi, substream);
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snd_midi_event_reset_decode(msynth->parser);
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} else {
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if (msynth->parser == NULL)
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return -EIO;
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len = snd_midi_event_decode(msynth->parser, msg, sizeof(msg), ev);
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if (len < 0)
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return 0;
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if (dump_midi(substream, msg, len) < 0)
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snd_midi_event_reset_decode(msynth->parser);
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}
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return 0;
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}
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static int snd_seq_midisynth_new(struct seq_midisynth *msynth,
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struct snd_card *card,
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int device,
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int subdevice)
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{
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if (snd_midi_event_new(MAX_MIDI_EVENT_BUF, &msynth->parser) < 0)
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return -ENOMEM;
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msynth->card = card;
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msynth->device = device;
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msynth->subdevice = subdevice;
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return 0;
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}
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/* open associated midi device for input */
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static int midisynth_subscribe(void *private_data, struct snd_seq_port_subscribe *info)
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{
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int err;
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struct seq_midisynth *msynth = private_data;
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struct snd_rawmidi_runtime *runtime;
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struct snd_rawmidi_params params;
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/* open midi port */
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err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
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msynth->subdevice,
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SNDRV_RAWMIDI_LFLG_INPUT,
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&msynth->input_rfile);
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if (err < 0) {
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pr_debug("ALSA: seq_midi: midi input open failed!!!\n");
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return err;
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}
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runtime = msynth->input_rfile.input->runtime;
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memset(¶ms, 0, sizeof(params));
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params.avail_min = 1;
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params.buffer_size = input_buffer_size;
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err = snd_rawmidi_input_params(msynth->input_rfile.input, ¶ms);
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if (err < 0) {
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snd_rawmidi_kernel_release(&msynth->input_rfile);
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return err;
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}
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snd_midi_event_reset_encode(msynth->parser);
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runtime->event = snd_midi_input_event;
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runtime->private_data = msynth;
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snd_rawmidi_kernel_read(msynth->input_rfile.input, NULL, 0);
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return 0;
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}
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/* close associated midi device for input */
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static int midisynth_unsubscribe(void *private_data, struct snd_seq_port_subscribe *info)
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{
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int err;
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struct seq_midisynth *msynth = private_data;
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if (snd_BUG_ON(!msynth->input_rfile.input))
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return -EINVAL;
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err = snd_rawmidi_kernel_release(&msynth->input_rfile);
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return err;
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}
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/* open associated midi device for output */
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static int midisynth_use(void *private_data, struct snd_seq_port_subscribe *info)
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{
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int err;
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struct seq_midisynth *msynth = private_data;
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struct snd_rawmidi_params params;
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/* open midi port */
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err = snd_rawmidi_kernel_open(msynth->card, msynth->device,
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msynth->subdevice,
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SNDRV_RAWMIDI_LFLG_OUTPUT,
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&msynth->output_rfile);
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if (err < 0) {
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pr_debug("ALSA: seq_midi: midi output open failed!!!\n");
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return err;
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}
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memset(¶ms, 0, sizeof(params));
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params.avail_min = 1;
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params.buffer_size = output_buffer_size;
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params.no_active_sensing = 1;
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err = snd_rawmidi_output_params(msynth->output_rfile.output, ¶ms);
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if (err < 0) {
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snd_rawmidi_kernel_release(&msynth->output_rfile);
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return err;
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}
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snd_midi_event_reset_decode(msynth->parser);
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return 0;
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}
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/* close associated midi device for output */
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static int midisynth_unuse(void *private_data, struct snd_seq_port_subscribe *info)
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{
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struct seq_midisynth *msynth = private_data;
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if (snd_BUG_ON(!msynth->output_rfile.output))
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return -EINVAL;
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snd_rawmidi_drain_output(msynth->output_rfile.output);
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return snd_rawmidi_kernel_release(&msynth->output_rfile);
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}
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/* delete given midi synth port */
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static void snd_seq_midisynth_delete(struct seq_midisynth *msynth)
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{
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if (msynth == NULL)
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return;
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if (msynth->seq_client > 0) {
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/* delete port */
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snd_seq_event_port_detach(msynth->seq_client, msynth->seq_port);
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}
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snd_midi_event_free(msynth->parser);
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}
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/* register new midi synth port */
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static int
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snd_seq_midisynth_probe(struct device *_dev)
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{
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struct snd_seq_device *dev = to_seq_dev(_dev);
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struct seq_midisynth_client *client;
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struct seq_midisynth *msynth, *ms;
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struct snd_seq_port_info *port;
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struct snd_rawmidi_info *info;
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struct snd_rawmidi *rmidi = dev->private_data;
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int newclient = 0;
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unsigned int p, ports;
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struct snd_seq_port_callback pcallbacks;
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struct snd_card *card = dev->card;
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int device = dev->device;
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unsigned int input_count = 0, output_count = 0;
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if (snd_BUG_ON(!card || device < 0 || device >= SNDRV_RAWMIDI_DEVICES))
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return -EINVAL;
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info = kmalloc(sizeof(*info), GFP_KERNEL);
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if (! info)
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return -ENOMEM;
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info->device = device;
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info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
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info->subdevice = 0;
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if (snd_rawmidi_info_select(card, info) >= 0)
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output_count = info->subdevices_count;
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info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
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if (snd_rawmidi_info_select(card, info) >= 0) {
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input_count = info->subdevices_count;
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}
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ports = output_count;
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if (ports < input_count)
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ports = input_count;
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if (ports == 0) {
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kfree(info);
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return -ENODEV;
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}
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if (ports > (256 / SNDRV_RAWMIDI_DEVICES))
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ports = 256 / SNDRV_RAWMIDI_DEVICES;
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mutex_lock(®ister_mutex);
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client = synths[card->number];
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if (client == NULL) {
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newclient = 1;
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client = kzalloc(sizeof(*client), GFP_KERNEL);
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if (client == NULL) {
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mutex_unlock(®ister_mutex);
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kfree(info);
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return -ENOMEM;
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}
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client->seq_client =
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snd_seq_create_kernel_client(
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card, 0, "%s", card->shortname[0] ?
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(const char *)card->shortname : "External MIDI");
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if (client->seq_client < 0) {
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kfree(client);
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mutex_unlock(®ister_mutex);
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kfree(info);
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return -ENOMEM;
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}
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}
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msynth = kcalloc(ports, sizeof(struct seq_midisynth), GFP_KERNEL);
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port = kmalloc(sizeof(*port), GFP_KERNEL);
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if (msynth == NULL || port == NULL)
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goto __nomem;
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for (p = 0; p < ports; p++) {
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ms = &msynth[p];
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if (snd_seq_midisynth_new(ms, card, device, p) < 0)
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goto __nomem;
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/* declare port */
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memset(port, 0, sizeof(*port));
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port->addr.client = client->seq_client;
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port->addr.port = device * (256 / SNDRV_RAWMIDI_DEVICES) + p;
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port->flags = SNDRV_SEQ_PORT_FLG_GIVEN_PORT;
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memset(info, 0, sizeof(*info));
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info->device = device;
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if (p < output_count)
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info->stream = SNDRV_RAWMIDI_STREAM_OUTPUT;
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else
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info->stream = SNDRV_RAWMIDI_STREAM_INPUT;
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info->subdevice = p;
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if (snd_rawmidi_info_select(card, info) >= 0)
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strcpy(port->name, info->subname);
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if (! port->name[0]) {
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if (info->name[0]) {
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if (ports > 1)
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snprintf(port->name, sizeof(port->name), "%s-%u", info->name, p);
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else
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snprintf(port->name, sizeof(port->name), "%s", info->name);
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} else {
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/* last resort */
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if (ports > 1)
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sprintf(port->name, "MIDI %d-%d-%u", card->number, device, p);
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else
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sprintf(port->name, "MIDI %d-%d", card->number, device);
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}
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}
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if ((info->flags & SNDRV_RAWMIDI_INFO_OUTPUT) && p < output_count)
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port->capability |= SNDRV_SEQ_PORT_CAP_WRITE | SNDRV_SEQ_PORT_CAP_SYNC_WRITE | SNDRV_SEQ_PORT_CAP_SUBS_WRITE;
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if ((info->flags & SNDRV_RAWMIDI_INFO_INPUT) && p < input_count)
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port->capability |= SNDRV_SEQ_PORT_CAP_READ | SNDRV_SEQ_PORT_CAP_SYNC_READ | SNDRV_SEQ_PORT_CAP_SUBS_READ;
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if ((port->capability & (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ)) == (SNDRV_SEQ_PORT_CAP_WRITE|SNDRV_SEQ_PORT_CAP_READ) &&
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info->flags & SNDRV_RAWMIDI_INFO_DUPLEX)
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port->capability |= SNDRV_SEQ_PORT_CAP_DUPLEX;
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port->type = SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC
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| SNDRV_SEQ_PORT_TYPE_HARDWARE
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| SNDRV_SEQ_PORT_TYPE_PORT;
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port->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 = ms;
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pcallbacks.subscribe = midisynth_subscribe;
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pcallbacks.unsubscribe = midisynth_unsubscribe;
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pcallbacks.use = midisynth_use;
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pcallbacks.unuse = midisynth_unuse;
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pcallbacks.event_input = event_process_midi;
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port->kernel = &pcallbacks;
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if (rmidi->ops && rmidi->ops->get_port_info)
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rmidi->ops->get_port_info(rmidi, p, port);
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if (snd_seq_kernel_client_ctl(client->seq_client, SNDRV_SEQ_IOCTL_CREATE_PORT, port)<0)
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goto __nomem;
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ms->seq_client = client->seq_client;
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ms->seq_port = port->addr.port;
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}
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client->ports_per_device[device] = ports;
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client->ports[device] = msynth;
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client->num_ports++;
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if (newclient)
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synths[card->number] = client;
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mutex_unlock(®ister_mutex);
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kfree(info);
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kfree(port);
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return 0; /* success */
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__nomem:
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if (msynth != NULL) {
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for (p = 0; p < ports; p++)
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snd_seq_midisynth_delete(&msynth[p]);
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kfree(msynth);
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}
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if (newclient) {
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snd_seq_delete_kernel_client(client->seq_client);
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kfree(client);
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}
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kfree(info);
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kfree(port);
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mutex_unlock(®ister_mutex);
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return -ENOMEM;
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}
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/* release midi synth port */
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static int
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snd_seq_midisynth_remove(struct device *_dev)
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{
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struct snd_seq_device *dev = to_seq_dev(_dev);
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struct seq_midisynth_client *client;
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struct seq_midisynth *msynth;
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struct snd_card *card = dev->card;
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int device = dev->device, p, ports;
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mutex_lock(®ister_mutex);
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client = synths[card->number];
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if (client == NULL || client->ports[device] == NULL) {
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mutex_unlock(®ister_mutex);
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return -ENODEV;
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}
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ports = client->ports_per_device[device];
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client->ports_per_device[device] = 0;
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msynth = client->ports[device];
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client->ports[device] = NULL;
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for (p = 0; p < ports; p++)
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snd_seq_midisynth_delete(&msynth[p]);
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kfree(msynth);
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client->num_ports--;
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if (client->num_ports <= 0) {
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snd_seq_delete_kernel_client(client->seq_client);
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synths[card->number] = NULL;
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kfree(client);
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}
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mutex_unlock(®ister_mutex);
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return 0;
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}
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static struct snd_seq_driver seq_midisynth_driver = {
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.driver = {
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.name = KBUILD_MODNAME,
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.probe = snd_seq_midisynth_probe,
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.remove = snd_seq_midisynth_remove,
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},
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.id = SNDRV_SEQ_DEV_ID_MIDISYNTH,
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.argsize = 0,
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};
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module_snd_seq_driver(seq_midisynth_driver);
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