ALSA: usb-audio: Create UMP blocks from USB MIDI GTBs

USB MIDI spec defines the Group Terminal Blocks (GTB) that associate
multiple UMP Groups.  Those correspond to snd_ump_block entities in
ALSA UMP abstraction, and now we create those UMP Block objects for
each UMP Endpoint from the parsed GTB information.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-13-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/midi2.c b/sound/usb/midi2.c
index 790e4cd5d35cc94911c7abcff687772f68809058..5ffee06ac746dc3e50e4a7395dd2946531d7ff29 100644 (file)
--- a/sound/usb/midi2.c
+++ b/sound/usb/midi2.c
@@ -599,14 +599,8 @@ find_group_terminal_block(struct snd_usb_midi2_interface *umidi, int id)
 static int parse_group_terminal_block(struct snd_usb_midi2_ump *rmidi,
                                      const struct usb_ms20_gr_trm_block_descriptor *desc)
 {
-       struct snd_usb_audio *chip = rmidi->umidi->chip;
        struct snd_ump_endpoint *ump = rmidi->ump;
 
-       usb_audio_dbg(chip,
-                     "GTB id %d: groups = %d / %d, type = %d\n",
-                     desc->bGrpTrmBlkID, desc->nGroupTrm, desc->nNumGroupTrm,
-                     desc->bGrpTrmBlkType);
-
        /* set default protocol */
        switch (desc->bMIDIProtocol) {
        case USB_MS_MIDI_PROTO_1_0_64:
@@ -798,6 +792,94 @@ static int find_matching_ep_partner(struct snd_usb_midi2_interface *umidi,
        return 0;
 }
 
+/* create a UMP block from a GTB entry */
+static int create_gtb_block(struct snd_usb_midi2_ump *rmidi, int dir, int blk)
+{
+       struct snd_usb_midi2_interface *umidi = rmidi->umidi;
+       const struct usb_ms20_gr_trm_block_descriptor *desc;
+       struct snd_ump_block *fb;
+       int type, err;
+
+       desc = find_group_terminal_block(umidi, blk);
+       if (!desc)
+               return 0;
+
+       usb_audio_dbg(umidi->chip,
+                     "GTB %d: type=%d, group=%d/%d, protocol=%d, in bw=%d, out bw=%d\n",
+                     blk, desc->bGrpTrmBlkType, desc->nGroupTrm,
+                     desc->nNumGroupTrm, desc->bMIDIProtocol,
+                     __le16_to_cpu(desc->wMaxInputBandwidth),
+                     __le16_to_cpu(desc->wMaxOutputBandwidth));
+
+       /* assign the direction */
+       switch (desc->bGrpTrmBlkType) {
+       case USB_MS_GR_TRM_BLOCK_TYPE_BIDIRECTIONAL:
+               type = SNDRV_UMP_DIR_BIDIRECTION;
+               break;
+       case USB_MS_GR_TRM_BLOCK_TYPE_INPUT_ONLY:
+               type = SNDRV_UMP_DIR_INPUT;
+               break;
+       case USB_MS_GR_TRM_BLOCK_TYPE_OUTPUT_ONLY:
+               type = SNDRV_UMP_DIR_OUTPUT;
+               break;
+       default:
+               usb_audio_dbg(umidi->chip, "Unsupported GTB type %d\n",
+                             desc->bGrpTrmBlkType);
+               return 0; /* unsupported */
+       }
+
+       /* guess work: set blk-1 as the (0-based) block ID */
+       err = snd_ump_block_new(rmidi->ump, blk - 1, type,
+                               desc->nGroupTrm, desc->nNumGroupTrm,
+                               &fb);
+       if (err == -EBUSY)
+               return 0; /* already present */
+       else if (err)
+               return err;
+
+       if (desc->iBlockItem)
+               usb_string(rmidi->dev, desc->iBlockItem,
+                          fb->info.name, sizeof(fb->info.name));
+
+       if (__le16_to_cpu(desc->wMaxInputBandwidth) == 1 ||
+           __le16_to_cpu(desc->wMaxOutputBandwidth) == 1)
+               fb->info.flags |= SNDRV_UMP_BLOCK_IS_MIDI1 |
+                       SNDRV_UMP_BLOCK_IS_LOWSPEED;
+
+       usb_audio_dbg(umidi->chip,
+                     "Created a UMP block %d from GTB, name=%s\n",
+                     blk, fb->info.name);
+       return 0;
+}
+
+/* Create UMP blocks for each UMP EP */
+static int create_blocks_from_gtb(struct snd_usb_midi2_interface *umidi)
+{
+       struct snd_usb_midi2_ump *rmidi;
+       int i, blk, err, dir;
+
+       list_for_each_entry(rmidi, &umidi->rawmidi_list, list) {
+               if (!rmidi->ump)
+                       continue;
+               /* Blocks have been already created? */
+               if (rmidi->ump->info.num_blocks)
+                       continue;
+               /* loop over GTBs */
+               for (dir = 0; dir < 2; dir++) {
+                       if (!rmidi->eps[dir])
+                               continue;
+                       for (i = 0; i < rmidi->eps[dir]->ms_ep->bNumGrpTrmBlock; i++) {
+                               blk = rmidi->eps[dir]->ms_ep->baAssoGrpTrmBlkID[i];
+                               err = create_gtb_block(rmidi, dir, blk);
+                               if (err < 0)
+                                       return err;
+                       }
+               }
+       }
+
+       return 0;
+}
+
 static void snd_usb_midi_v2_free(struct snd_usb_midi2_interface *umidi)
 {
        free_all_midi2_endpoints(umidi);
@@ -1009,6 +1091,12 @@ int snd_usb_midi_v2_create(struct snd_usb_audio *chip,
                goto error;
        }
 
+       err = create_blocks_from_gtb(umidi);
+       if (err < 0) {
+               usb_audio_err(chip, "Failed to create GTB blocks\n");
+               goto error;
+       }
+
        set_fallback_rawmidi_names(umidi);
        return 0;