Commit ff49d1df authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: USB MIDI 2.0 UMP support 



This patch provides a basic support for USB MIDI 2.0.  As of this
patch, the driver creates a UMP device per MIDI I/O endpoints, which
serves as a dumb terminal to read/write UMP streams.

A new Kconfig CONFIG_SND_USB_AUDIO_MIDI_V2 manages whether to enable
or disable the MIDI 2.0 support.  Also, the driver provides a new
module option, midi2_enable, to allow disabling the MIDI 2.0 at
runtime, too.  When MIDI 2.0 support is disabled, the driver tries to
fall back to the already existing MIDI 1.0 device (each MIDI 2.0
device is supposed to provide the MIDI 1.0 interface at the altset
0).

For now, the driver doesn't manage any MIDI-CI or other protocol
setups by itself, but relies on the default protocol given via the
group terminal block descriptors.

The MIDI 1.0 messages on MIDI 2.0 device will be automatically
converted in ALSA sequencer in a later patch.  As of this commit, the
driver accepts merely the rawmidi UMP accesses.

The driver builds up the topology in the following way:
- Create an object for each MIDI endpoint belonging to the USB
  interface
- Find MIDI EP "pairs" that share the same GTB;
  note that MIDI EP is unidirectional, while UMP is (normally)
  bidirectional, so two MIDI EPs can form a single UMP EP
- A UMP endpoint object is created for each I/O pair
- For remaining "solo" MIDI EPs, create unidirectional UMP EPs
- Finally, parse GTBs and fill the protocol bits on each UMP

So the driver may support multiple UMP Endpoints in theory, although
most devices are supposed to have a single UMP EP that can contain up
to 16 groups -- which should be large enough.

Reviewed-by: default avatarJaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-10-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent f8ddb0fb

sound/usb/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ config SND_USB_AUDIO 
	select SND_HWDEP

	select SND_RAWMIDI

	select SND_PCM

	select SND_UMP if SND_USB_AUDIO_MIDI_V2

	select BITREVERSE

	select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO)

	help
@@ -24,6 +25,16 @@ config SND_USB_AUDIO 
	  To compile this driver as a module, choose M here: the module

	  will be called snd-usb-audio.



config SND_USB_AUDIO_MIDI_V2

	bool "MIDI 2.0 support by USB Audio driver"

	depends on SND_USB_AUDIO

	help

	  Say Y here to include the support for MIDI 2.0 by USB Audio driver.

	  When the config is set, the driver tries to probe MIDI 2.0 interface

	  at first, then falls back to MIDI 1.0 interface as default.

	  The MIDI 2.0 support can be disabled dynamically via midi2_enable

	  module option, too.



config SND_USB_AUDIO_USE_MEDIA_CONTROLLER

	bool

sound/usb/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -22,6 +22,7 @@ snd-usb-audio-objs := card.o \ 
			stream.o \

			validate.o



snd-usb-audio-$(CONFIG_SND_USB_AUDIO_MIDI_V2) += midi2.o

snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o



snd-usbmidi-lib-objs := midi.o

sound/usb/card.c

+9 −4
Original line number Diff line number Diff line
@@ -44,6 +44,7 @@ 
#include "usbaudio.h"

#include "card.h"

#include "midi.h"

#include "midi2.h"

#include "mixer.h"

#include "proc.h"

#include "quirks.h"
@@ -178,10 +179,8 @@ static int snd_usb_create_stream(struct snd_usb_audio *chip, int ctrlif, int int 
	if ((altsd->bInterfaceClass == USB_CLASS_AUDIO ||

	     altsd->bInterfaceClass == USB_CLASS_VENDOR_SPEC) &&

	    altsd->bInterfaceSubClass == USB_SUBCLASS_MIDISTREAMING) {

		int err = __snd_usbmidi_create(chip->card, iface,

					       &chip->midi_list, NULL,

					       chip->usb_id,

					       &chip->num_rawmidis);

		int err = snd_usb_midi_v2_create(chip, iface, NULL,

						 chip->usb_id);

		if (err < 0) {

			dev_err(&dev->dev,

				"%u:%d: cannot create sequencer device\n",
@@ -486,6 +485,7 @@ static void snd_usb_audio_free(struct snd_card *card) 
	struct snd_usb_audio *chip = card->private_data;



	snd_usb_endpoint_free_all(chip);

	snd_usb_midi_v2_free_all(chip);



	mutex_destroy(&chip->mutex);

	if (!atomic_read(&chip->shutdown))
@@ -645,6 +645,7 @@ static int snd_usb_audio_create(struct usb_interface *intf, 
	INIT_LIST_HEAD(&chip->iface_ref_list);

	INIT_LIST_HEAD(&chip->clock_ref_list);

	INIT_LIST_HEAD(&chip->midi_list);

	INIT_LIST_HEAD(&chip->midi_v2_list);

	INIT_LIST_HEAD(&chip->mixer_list);



	if (quirk_flags[idx])
@@ -969,6 +970,7 @@ static void usb_audio_disconnect(struct usb_interface *intf) 
		list_for_each(p, &chip->midi_list) {

			snd_usbmidi_disconnect(p);

		}

		snd_usb_midi_v2_disconnect_all(chip);

		/*

		 * Nice to check quirk && quirk->shares_media_device and

		 * then call the snd_media_device_delete(). Don't have
@@ -1080,6 +1082,7 @@ static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message) 
			snd_usbmidi_suspend(p);

		list_for_each_entry(mixer, &chip->mixer_list, list)

			snd_usb_mixer_suspend(mixer);

		snd_usb_midi_v2_suspend_all(chip);

	}



	if (!PMSG_IS_AUTO(message) && !chip->system_suspend) {
@@ -1125,6 +1128,8 @@ static int usb_audio_resume(struct usb_interface *intf) 
		snd_usbmidi_resume(p);

	}



	snd_usb_midi_v2_resume_all(chip);



 out:

	if (chip->num_suspended_intf == chip->system_suspend) {

		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);

sound/usb/midi2.c

0 → 100644
+1052 −0

File added.

Preview size limit exceeded, changes collapsed.

sound/usb/midi2.h

0 → 100644
+33 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-or-later

#ifndef __USB_AUDIO_MIDI2_H

#define __USB_AUDIO_MIDI2_H



#include "midi.h"



#if IS_ENABLED(CONFIG_SND_USB_AUDIO_MIDI_V2)

int snd_usb_midi_v2_create(struct snd_usb_audio *chip,

			   struct usb_interface *iface,

			   const struct snd_usb_audio_quirk *quirk,

			   unsigned int usb_id);

void snd_usb_midi_v2_suspend_all(struct snd_usb_audio *chip);

void snd_usb_midi_v2_resume_all(struct snd_usb_audio *chip);

void snd_usb_midi_v2_disconnect_all(struct snd_usb_audio *chip);

void snd_usb_midi_v2_free_all(struct snd_usb_audio *chip);

#else /* CONFIG_SND_USB_AUDIO_MIDI_V2 */

/* fallback to MIDI 1.0 creation */

static inline int snd_usb_midi_v2_create(struct snd_usb_audio *chip,

					 struct usb_interface *iface,

					 const struct snd_usb_audio_quirk *quirk,

					 unsigned int usb_id)

{

	return __snd_usbmidi_create(chip->card, iface, &chip->midi_list,

				    quirk, usb_id, &chip->num_rawmidis);

}



static inline void snd_usb_midi_v2_suspend_all(struct snd_usb_audio *chip) {}

static inline void snd_usb_midi_v2_resume_all(struct snd_usb_audio *chip) {}

static inline void snd_usb_midi_v2_disconnect_all(struct snd_usb_audio *chip) {}

static inline void snd_usb_midi_v2_free_all(struct snd_usb_audio *chip) {}

#endif /* CONFIG_SND_USB_AUDIO_MIDI_V2 */



#endif /* __USB_AUDIO_MIDI2_H */