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>

5 files changed, 125 insertions, 0 deletions

diff --git a/sound/usb/midi.c b/sound/usb/midi.c
index 2c1558c327bb..9c23d89066e4 100644
--- a/sound/usb/midi.c
+++ b/sound/usb/midi.c
@@ -645,6 +645,105 @@ static struct usb_protocol_ops snd_usbmidi_cme_ops = {
 };
 
 /*
+ * 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 @@ static struct port_info {
         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 @@ int snd_usbmidi_create(struct snd_card *card,
                 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;
diff --git a/sound/usb/midi.h b/sound/usb/midi.h
index 2089ec987c66..2fca80b744c0 100644
--- a/sound/usb/midi.h
+++ b/sound/usb/midi.h
@@ -37,6 +37,8 @@ struct snd_usb_midi_endpoint_info {
 
 /* for QUIRK_MIDI_CME, data is NULL */
 
+/* for QUIRK_MIDI_AKAI, data is NULL */
+
 int snd_usbmidi_create(struct snd_card *card,
                        struct usb_interface *iface,
                        struct list_head *midi_list,
diff --git a/sound/usb/quirks-table.h b/sound/usb/quirks-table.h
index 91ddef31bcbd..f8797f61a24b 100644
--- a/sound/usb/quirks-table.h
+++ b/sound/usb/quirks-table.h
@@ -1973,6 +1973,17 @@ YAMAHA_DEVICE(0x7010, "UB99"),
         }
 },
 
+/* AKAI devices */
+{
+        USB_DEVICE(0x09e8, 0x0062),
+        .driver_info = (unsigned long) & (const struct snd_usb_audio_quirk) {
+                .vendor_name = "AKAI",
+                .product_name = "MPD16",
+                .ifnum = 0,
+                .type = QUIRK_MIDI_AKAI,
+        }
+},
+
 /* TerraTec devices */
 {
         USB_DEVICE_VENDOR_SPEC(0x0ccd, 0x0012),
diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index 136e5b4cf6de..b45e54c09ba2 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -289,6 +289,7 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
                 [QUIRK_MIDI_FASTLANE] = create_any_midi_quirk,
                 [QUIRK_MIDI_EMAGIC] = create_any_midi_quirk,
                 [QUIRK_MIDI_CME] = create_any_midi_quirk,
+                [QUIRK_MIDI_AKAI] = create_any_midi_quirk,
                 [QUIRK_AUDIO_STANDARD_INTERFACE] = create_standard_audio_quirk,
                 [QUIRK_AUDIO_FIXED_ENDPOINT] = create_fixed_stream_quirk,
                 [QUIRK_AUDIO_EDIROL_UAXX] = create_uaxx_quirk,
diff --git a/sound/usb/usbaudio.h b/sound/usb/usbaudio.h
index d679e72a3e5c..06ebf24d3a4d 100644
--- a/sound/usb/usbaudio.h
+++ b/sound/usb/usbaudio.h
@@ -74,6 +74,7 @@ enum quirk_type {
         QUIRK_MIDI_FASTLANE,
         QUIRK_MIDI_EMAGIC,
         QUIRK_MIDI_CME,
+        QUIRK_MIDI_AKAI,
         QUIRK_MIDI_US122L,
         QUIRK_AUDIO_STANDARD_INTERFACE,
         QUIRK_AUDIO_FIXED_ENDPOINT,