From patchwork Thu Aug 24 07:51:08 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Takashi Iwai X-Patchwork-Id: 13363687 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from alsa0.perex.cz (alsa0.perex.cz [77.48.224.243]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 16D4EC3DA6F for ; Thu, 24 Aug 2023 07:53:01 +0000 (UTC) Received: from alsa1.perex.cz (alsa1.perex.cz [207.180.221.201]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by alsa0.perex.cz (Postfix) with ESMTPS id 179BD84D; Thu, 24 Aug 2023 09:52:10 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa0.perex.cz 179BD84D DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=alsa-project.org; s=default; t=1692863580; bh=1LPIAPgHqcUP5VQM6IQUhEjMcZhe3uLVFoaG+ZNQqfw=; h=From:To:Subject:Date:In-Reply-To:References:List-Id:List-Archive: List-Help:List-Owner:List-Post:List-Subscribe:List-Unsubscribe: From; b=d8Fzkon+cK8uZ5vRcG1tAZgM3bOe9DiUzqJzbBr53b+BQPq6SYCYpc1xiMpqevFok 0709rW2YEjG0cAMHAudfdZ8AD1dCNLlA1PezUy1u142+R4B1P3oO0Fkj3NlD7TrJM4 UPP6IYdAPsB/Ek8yZ0nNKzyCxCZovZHY4rDNe1H0= Received: by alsa1.perex.cz (Postfix, from userid 50401) id 07408F80552; Thu, 24 Aug 2023 09:51:21 +0200 (CEST) Received: from mailman-core.alsa-project.org (mailman-core.alsa-project.org [10.254.200.10]) by alsa1.perex.cz (Postfix) with ESMTP id 71D70F8055A; Thu, 24 Aug 2023 09:51:21 +0200 (CEST) Received: by alsa1.perex.cz (Postfix, from userid 50401) id 1CEB0F8025F; Thu, 24 Aug 2023 09:51:16 +0200 (CEST) Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by alsa1.perex.cz (Postfix) with ESMTPS id 0C045F8022B for ; Thu, 24 Aug 2023 09:51:12 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 alsa1.perex.cz 0C045F8022B Authentication-Results: alsa1.perex.cz; dkim=pass (1024-bit key, unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256 header.s=susede2_rsa header.b=X1+mte/q; dkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256 header.s=susede2_ed25519 header.b=BqOCBEFh Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 4C74722CC0; Thu, 24 Aug 2023 07:51:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1692863471; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YghiKRcgLFIsxq+fLwAH4m1a20sGATL7xsSuDRkcDkQ=; b=X1+mte/qR5XtoP0a7SmAYlv98Kn/0zEJQpG8XTU9N7omoOGdK5P4GVa9W3r+8RZcC+khVB Sg/7vpu0pjkFHxGgim940htT5O6paYeoToPfbf7c3Lmjd4UC7egcurUW9ifsZC6wn41yJM Ct+b75jF8RdYVAfyLphZRpD8P7cGtmY= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1692863471; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YghiKRcgLFIsxq+fLwAH4m1a20sGATL7xsSuDRkcDkQ=; b=BqOCBEFhIGxDODMzoH+H+iniQNQ0K3x9R4GKioyCnmK1/xuRpPVPkdE/MOAlh3SWZnugMe u2AvELCcvVXMa5Ag== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 2F034139BC; Thu, 24 Aug 2023 07:51:11 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id sLSpCu8L52TtLAAAMHmgww (envelope-from ); Thu, 24 Aug 2023 07:51:11 +0000 From: Takashi Iwai To: alsa-devel@alsa-project.org Subject: [PATCH 4/4] ALSA: documentation: Add description for USB MIDI 2.0 gadget driver Date: Thu, 24 Aug 2023 09:51:08 +0200 Message-Id: <20230824075108.29958-5-tiwai@suse.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20230824075108.29958-1-tiwai@suse.de> References: <20230824075108.29958-1-tiwai@suse.de> MIME-Version: 1.0 Message-ID-Hash: 5RTIQE6PHYI3ZVQ4HZ5H7PAHCN47WLQP X-Message-ID-Hash: 5RTIQE6PHYI3ZVQ4HZ5H7PAHCN47WLQP X-MailFrom: tiwai@suse.de X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; header-match-alsa-devel.alsa-project.org-0; header-match-alsa-devel.alsa-project.org-1; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header X-Mailman-Version: 3.3.8 Precedence: list List-Id: "Alsa-devel mailing list for ALSA developers - http://www.alsa-project.org" Archived-At: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: The USB MIDI 2.0 gadget driver is now supported for 6.6 kernel, and here we show a brief instruction how to enable and use it. Signed-off-by: Takashi Iwai --- Documentation/sound/designs/midi-2.0.rst | 188 +++++++++++++++++++++++ 1 file changed, 188 insertions(+) diff --git a/Documentation/sound/designs/midi-2.0.rst b/Documentation/sound/designs/midi-2.0.rst index 27d0d3dea1b0..3b08b98354f8 100644 --- a/Documentation/sound/designs/midi-2.0.rst +++ b/Documentation/sound/designs/midi-2.0.rst @@ -376,3 +376,191 @@ Sequencer API Extensions name and attributes accordingly, and notifies the changes via the announcement to the ALSA sequencer system port, similarly like the normal port change notification. + + +MIDI2 USB Gadget Function Driver +================================ + +The latest kernel contains the support for USB MIDI 2.0 gadget +function driver, which can be used for prototyping and debugging MIDI +2.0 features. + +`CONFIG_USB_GADGET`, `CONFIG_USB_CONFIGFS` and +`CONFIG_USB_CONFIGFS_F_MIDI2` need to be enabled for the MIDI2 gadget +driver. + +In addition, for using a gadget driver, you need a working UDC driver. +In the example below, we use `dummy_hcd` driver (enabled via +`CONFIG_USB_DUMMY_HCD`) that is available on PC and VM for debugging +purpose. There are other UDC drivers depending on the platform, and +those can be used for a real device, instead, too. + +At first, on a system to run the gadget, load `libcomposite` module:: + + % modprobe libcomposite + +and you'll have `usb_gadget` subdirectory under configfs space +(typically `/sys/kernel/config` on modern OS). Then create a gadget +instance and add configurations there, for example:: + + % cd /sys/kernel/config + % mkdir usb_gadget/g1 + + % cd usb_gadget/g1 + % mkdir configs/c.1 + % mkdir functions/midi2.usb0 + + % echo 0x0004 > idProduct + % echo 0x17b3 > idVendor + % mkdir strings/0x409 + % echo "ACME Enterprises" > strings/0x409/manufacturer + % echo "ACMESynth" > strings/0x409/product + % echo "ABCD12345" > strings/0x409/serialnumber + + % mkdir configs/c.1/strings/0x409 + % echo "Monosynth" > configs/c.1/strings/0x409/configuration + % echo 120 > configs/c.1/MaxPower + +At this point, there must be a subdirectory `ep.0`, and that is the +configuration for a UMP Endpoint. You can fill the Endpoint +information like:: + + % echo "ACMESynth" > functions/midi2.usb0/iface_name + % echo "ACMESynth" > functions/midi2.usb0/ep.0/ep_name + % echo "ABCD12345" > functions/midi2.usb0/ep.0/product_id + % echo 0x0123 > functions/midi2.usb0/ep.0/family + % echo 0x4567 > functions/midi2.usb0/ep.0/model + % echo 0x123456 > functions/midi2.usb0/ep.0/manufacturer + % echo 0x12345678 > functions/midi2.usb0/ep.0/sw_revision + +The default MIDI protocol can be set either 1 or 2:: + + % echo 2 > functions/midi2.usb0/ep.0/protocol + +And, you can find a subdirectory `block.0` under this Endpoint +subdirectory. This defines the Function Block information:: + + % echo "Monosynth" > functions/midi2.usb0/ep.0/block.0/name + % echo 0 > functions/midi2.usb0/ep.0/block.0/first_group + % echo 1 > functions/midi2.usb0/ep.0/block.0/num_groups + +Finally, link the configuration and enable it:: + + % ln -s functions/midi2.usb0 configs/c.1 + % echo dummy_udc.0 > UDC + +where `dummy_udc.0` is an example case and it differs depending on the +system. You can find the UDC instances in `/sys/class/udc` and pass +the found name instead:: + + % ls /sys/class/udc + dummy_udc.0 + +Now, the MIDI 2.0 gadget device is enabled, and the gadget host +creates a new sound card instance containing a UMP rawmidi device by +`f_midi2` driver:: + + % cat /proc/asound/cards + .... + 1 [Gadget ]: f_midi2 - MIDI 2.0 Gadget + MIDI 2.0 Gadget + +And on the connected host, a similar card should appear, too, but with +the card and device names given in the configfs above:: + + % cat /proc/asound/cards + .... + 2 [ACMESynth ]: USB-Audio - ACMESynth + ACME Enterprises ACMESynth at usb-dummy_hcd.0-1, high speed + +You can play a MIDI file on the gadget side:: + + % aplaymidi -p 20:1 to_host.mid + +and this will appear as an input from a MIDI device on the connected +host:: + + % aseqdump -p 20:0 -u 2 + +Vice versa, a playback on the connected host will work as an input on +the gadget, too. + +Each Function Block may have different direction and UI-hint, +specified via `direction` and `ui_hint` attributes. +Passing `1` is for input-only, `2` for out-only and `3` for +bidirectional (the default value). For example:: + + % echo 2 > functions/midi2.usb0/ep.0/block.0/direction + % echo 2 > functions/midi2.usb0/ep.0/block.0/ui_hint + +When you need more than one Function Blocks, you can create +subdirectories `block.1`, `block.2`, etc dynamically, and configure +them in the configuration procedure above before linking. +For example, to create a second Function Block for a keyboard:: + + % mkdir functions/midi2.usb0/ep.0/block.1 + % echo "Keyboard" > functions/midi2.usb0/ep.0/block.1/name + % echo 1 > functions/midi2.usb0/ep.0/block.1/first_group + % echo 1 > functions/midi2.usb0/ep.0/block.1/num_groups + % echo 1 > functions/midi2.usb0/ep.0/block.1/direction + % echo 1 > functions/midi2.usb0/ep.0/block.1/ui_hint + +The `block.*` subdirectories can be removed dynamically, too (except +for `block.0` which is persistent). + +For assigning a Function Block for MIDI 1.0 I/O, set up in `is_midi1` +attribute. 1 is for MIDI 1.0, and 2 is for MIDI 1.0 with low speed +connection:: + + % echo 2 > functions/midi2.usb0/ep.0/block.1/is_midi1 + +For disabling the processing of UMP Stream messages in the gadget +driver, pass `0` to `process_ump attribute in the top-level config:: + + % echo 0 > functions/midi2.usb0/process_ump + +The MIDI 1.0 interface at altset 0 is supported by the gadget driver, +too. When MIDI 1.0 interface is selected by the connected host, the +UMP I/O on the gadget is translated from/to USB MIDI 1.0 packets +accordingly while the gadget driver keeps communicating with the +user-space over UMP rawmidi. + +MIDI 1.0 ports are set up from the config in each Function Block. +For example:: + + % echo 0 > functions/midi2.usb0/ep.0/block.0/midi1_first_group + % echo 1 > functions/midi2.usb0/ep.0/block.0/midi1_num_groups + +The configuration above will enable the Group 1 (the index 0) for MIDI +1.0 interface. Note that those groups must be in the groups defined +for the Function Block itself. + +The gadget driver supports more than one UMP Endpoints, too. +Similarly like the Function Blocks, you can create a new subdirectory +`ep.1` (but under the card top-level config) to enable a new Endpoint:: + + % mkdir functions/midi2.usb0/ep.1 + +and create a new Function Block there. For example, to create 4 +Groups for the Function Block of this new Endpoint:: + + % mkdir functions/midi2.usb0/ep.1/block.0 + % echo 4 > functions/midi2.usb0/ep.1/block.0/num_groups + +Now, you'll have 4 rawmidi devices in total: the first two are UMP +rawmidi devices for Endpoint 0 and Endpoint 1, and other two for the +legacy MIDI 1.0 rawmidi devices corresponding to both EP 0 and EP 1. + +The current altsetting on the gadget can be informed via a control +element "Operation Mode" with `RAWMIDI` iface. e.g. you can read it +via `amixer` program running on the gadget host like:: + + % amixer -c1 cget iface=RAWMIDI,name='Operation Mode' + ; type=INTEGER,access=r--v----,values=1,min=0,max=2,step=0 + : values=2 + +The value (shown in the second returned line with `: values=`) +indicates 1 for MIDI 1.0 (altset 0), 2 for MIDI 2.0 (altset 1) and 0 +for unset. + +As of now, the configurations can't be changed after binding.