ALSA: usb-audio: add support for Akai MPD16
The decoding/encoding is based on own reverse-engineering. Both control and
data ports are handled. Writing to control port supports SysEx events only,
as this is the only type of messages that MPD16 recognizes.
Signed-off-by: Krzysztof Foltman <wdev@foltman.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index 2c1558c..9c23d89 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -645,6 +645,105 @@
};
/*
+ * AKAI MPD16 protocol:
+ *
+ * For control port (endpoint 1):
+ * ==============================
+ * One or more chunks consisting of first byte of (0x10 | msg_len) and then a
+ * SysEx message (msg_len=9 bytes long).
+ *
+ * For data port (endpoint 2):
+ * ===========================
+ * One or more chunks consisting of first byte of (0x20 | msg_len) and then a
+ * MIDI message (msg_len bytes long)
+ *
+ * Messages sent: Active Sense, Note On, Poly Pressure, Control Change.
+ */
+static void snd_usbmidi_akai_input(struct snd_usb_midi_in_endpoint *ep,
+ uint8_t *buffer, int buffer_length)
+{
+ unsigned int pos = 0;
+ unsigned int len = (unsigned int)buffer_length;
+ while (pos < len) {
+ unsigned int port = (buffer[pos] >> 4) - 1;
+ unsigned int msg_len = buffer[pos] & 0x0f;
+ pos++;
+ if (pos + msg_len <= len && port < 2)
+ snd_usbmidi_input_data(ep, 0, &buffer[pos], msg_len);
+ pos += msg_len;
+ }
+}
+
+#define MAX_AKAI_SYSEX_LEN 9
+
+static void snd_usbmidi_akai_output(struct snd_usb_midi_out_endpoint *ep,
+ struct urb *urb)
+{
+ uint8_t *msg;
+ int pos, end, count, buf_end;
+ uint8_t tmp[MAX_AKAI_SYSEX_LEN];
+ struct snd_rawmidi_substream *substream = ep->ports[0].substream;
+
+ if (!ep->ports[0].active)
+ return;
+
+ msg = urb->transfer_buffer + urb->transfer_buffer_length;
+ buf_end = ep->max_transfer - MAX_AKAI_SYSEX_LEN - 1;
+
+ /* only try adding more data when there's space for at least 1 SysEx */
+ while (urb->transfer_buffer_length < buf_end) {
+ count = snd_rawmidi_transmit_peek(substream,
+ tmp, MAX_AKAI_SYSEX_LEN);
+ if (!count) {
+ ep->ports[0].active = 0;
+ return;
+ }
+ /* try to skip non-SysEx data */
+ for (pos = 0; pos < count && tmp[pos] != 0xF0; pos++)
+ ;
+
+ if (pos > 0) {
+ snd_rawmidi_transmit_ack(substream, pos);
+ continue;
+ }
+
+ /* look for the start or end marker */
+ for (end = 1; end < count && tmp[end] < 0xF0; end++)
+ ;
+
+ /* next SysEx started before the end of current one */
+ if (end < count && tmp[end] == 0xF0) {
+ /* it's incomplete - drop it */
+ snd_rawmidi_transmit_ack(substream, end);
+ continue;
+ }
+ /* SysEx complete */
+ if (end < count && tmp[end] == 0xF7) {
+ /* queue it, ack it, and get the next one */
+ count = end + 1;
+ msg[0] = 0x10 | count;
+ memcpy(&msg[1], tmp, count);
+ snd_rawmidi_transmit_ack(substream, count);
+ urb->transfer_buffer_length += count + 1;
+ msg += count + 1;
+ continue;
+ }
+ /* less than 9 bytes and no end byte - wait for more */
+ if (count < MAX_AKAI_SYSEX_LEN) {
+ ep->ports[0].active = 0;
+ return;
+ }
+ /* 9 bytes and no end marker in sight - malformed, skip it */
+ snd_rawmidi_transmit_ack(substream, count);
+ }
+}
+
+static struct usb_protocol_ops snd_usbmidi_akai_ops = {
+ .input = snd_usbmidi_akai_input,
+ .output = snd_usbmidi_akai_output,
+};
+
+/*
* Novation USB MIDI protocol: number of data bytes is in the first byte
* (when receiving) (+1!) or in the second byte (when sending); data begins
* at the third byte.
@@ -1434,6 +1533,11 @@
EXTERNAL_PORT(0x086a, 0x0001, 8, "%s Broadcast"),
EXTERNAL_PORT(0x086a, 0x0002, 8, "%s Broadcast"),
EXTERNAL_PORT(0x086a, 0x0003, 4, "%s Broadcast"),
+ /* Akai MPD16 */
+ CONTROL_PORT(0x09e8, 0x0062, 0, "%s Control"),
+ PORT_INFO(0x09e8, 0x0062, 1, "%s MIDI", 0,
+ SNDRV_SEQ_PORT_TYPE_MIDI_GENERIC |
+ SNDRV_SEQ_PORT_TYPE_HARDWARE),
/* Access Music Virus TI */
EXTERNAL_PORT(0x133e, 0x0815, 0, "%s MIDI"),
PORT_INFO(0x133e, 0x0815, 1, "%s Synth", 0,
@@ -2035,6 +2139,12 @@
umidi->usb_protocol_ops = &snd_usbmidi_cme_ops;
err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
break;
+ case QUIRK_MIDI_AKAI:
+ umidi->usb_protocol_ops = &snd_usbmidi_akai_ops;
+ err = snd_usbmidi_detect_per_port_endpoints(umidi, endpoints);
+ /* endpoint 1 is input-only */
+ endpoints[1].out_cables = 0;
+ break;
default:
snd_printd(KERN_ERR "invalid quirk type %d\n", quirk->type);
err = -ENXIO;