Commit d9c99876 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

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: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-13-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 51701400

sound/usb/midi2.c

+94 −6
Original line number Diff line number Diff line
@@ -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;