From patchwork Tue Aug 6 12:52:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Orlov X-Patchwork-Id: 13754804 Received: from mail-wm1-f44.google.com (mail-wm1-f44.google.com [209.85.128.44]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8AF281DFC7; Tue, 6 Aug 2024 12:52:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.44 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948772; cv=none; b=BbMUQi0tFwmt4NGyiundgwwykJ1p9bpYAibbiuB+QH0GSh5YY1CfB8foXFfyEVTRrhlU+Unpr2DtCFQXNlvZ5pQVhwgjfRdqwwdYO4KqTZ5UmnJI+0DDjgjxj3Hif/NC/2SLVbjbC/MlTFzJxri9OB+3EzuFpCPhrgt7/4qKr3o= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948772; c=relaxed/simple; bh=oHsucPMxdYbxpAwRnQO8U+6dli+bDmAiev5mUhaGzCI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=dXdiWHwfIjxQ39pwKm2YBSULBM05F7Ia8Pw6+EgITW3DTLdvhj3BeCdt4NPcB25pdzi1uzESeNStfxv7EnPDrC1CrrdOwzT3iTSZ6OqMhxkjNWgQjYep8CXr2uiccHhEovq0IOs1woHdBd5I2tGo9QTEio2ywa4c6NG8Mf4wwUQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=RiQUGxvO; arc=none smtp.client-ip=209.85.128.44 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="RiQUGxvO" Received: by mail-wm1-f44.google.com with SMTP id 5b1f17b1804b1-4280921baa2so297635e9.2; Tue, 06 Aug 2024 05:52:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722948769; x=1723553569; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=UNsqINAtNbB/7aNiOKVrlsTW1P1GcvahhFjOdWwa67k=; b=RiQUGxvOGMabGUAYYqM+P1q7jywaAxddf5p02JcFcfxfeqbrwc1vy9bEveGWJ9fP32 0RhGhawvLA6Bf7Loc8JmOMO3H900tcx7zDioCy61EUaGMZ9Ugc35WO7Ny/l1FLy5vtKt ICazL95NtYk8BqOHB49tNhah5n+k3Ej+JVRZejEBNtFT9i1RLrDN9ik81WNtx0GgKsuy vexPj9RCI7n11pCvW+WOezVrt9lN2DvD3lYR/WmYL24lUkZ5EaLNWXQuKH8kWdZD16Oz XP2+6jxQCeSR9QOXTsVHch0mVlW2zMPYo6OAjln8V2MFEufhWbvGupDjGXVrdPP1S7GR GJmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722948769; x=1723553569; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=UNsqINAtNbB/7aNiOKVrlsTW1P1GcvahhFjOdWwa67k=; b=sC63hW9AUDrMZto/mQOy4TL/O2G6G2CWtHYRNCdfWyN8OAJYS2UQ65KOgr5ga+PL5r 08VN52FdYedVG+mVb94sEZ6Va/5SIFkl49aGUZ2kJScsXY4vBtfL3hDgsdAvnVENRlKt tNh7s7F/hrIDqkEr/bGZNCJp7topXyEI98j7CZxZfJawVGNUvWqwlcPjenHhh1sd01td w1utco5odwGciFZTEYVi5N1Twv8Yrv2gyH6gihf4eCNEJYxByRddW7j9rjTiw8hRWIXM WBypRSDkvTrc6YQJXrd8+qen3Gua4+8g1rrVg2ixdkln41WAXIsh2V6Z7kW0D0qOSeD0 UeUA== X-Forwarded-Encrypted: i=1; AJvYcCW1P3cYlBaZzma1UQNR4p1R++CJnwqHNnCWZVwRGOqW47TQI0K4iqGuyaerkjsFX5HceeYofOg3OGo3AMvXMFEHuhtbyycN/qiwAxZecFP/K63XhBkxaIBQnKw8GXpEwWR6m83X6s+jZkNrVpYOCt8AHPgcdd/jxxOE5fWn1T5ORXGRvSCuxkVZwxaRvk+WKPRGIRoi6oYaYTIDvBm23Icd0LUcj80= X-Gm-Message-State: AOJu0Yxq+5ilaHtgrLMcvUVfl+Kcnb9CnkAgAZ7Ba647O5RsmP26NvmU 1LcSoqRoLjQGlKlCvv6RotqqzNrh/9hmHt4Wu+Cr5Av3TdZRNC7S X-Google-Smtp-Source: AGHT+IHfG6l8sknkwJmvO1EpQVnCVeAbWu7CQd33ZI5ukBgYOkpaJK/1bDpUYyD/Iqhret4NBaOPXw== X-Received: by 2002:a05:600c:3152:b0:427:9f6f:4913 with SMTP id 5b1f17b1804b1-428ea0fd688mr63195795e9.5.1722948768682; Tue, 06 Aug 2024 05:52:48 -0700 (PDT) Received: from ivan-HLYL-WXX9.. ([2a01:4b00:d20e:7300:b50e:24fa:fd17:c835]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-428e6d648a0sm179487255e9.10.2024.08.06.05.52.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 05:52:48 -0700 (PDT) From: Ivan Orlov To: perex@perex.cz, tiwai@suse.com, corbet@lwn.net, broonie@kernel.org, shuah@kernel.org Cc: Ivan Orlov , linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, christophe.jaillet@wanadoo.fr, aholzinger@gmx.de Subject: [PATCH v3 1/4] ALSA: aloop: Allow using global timers Date: Tue, 6 Aug 2024 13:52:40 +0100 Message-Id: <20240806125243.449959-2-ivan.orlov0322@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240806125243.449959-1-ivan.orlov0322@gmail.com> References: <20240806125243.449959-1-ivan.orlov0322@gmail.com> Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Allow using global timers as a timer source when card id is equal to -1 in the timer_source parameter. Signed-off-by: Ivan Orlov --- V1 -> V2: - No changes V2 -> V3: - No changes sound/drivers/aloop.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/drivers/aloop.c b/sound/drivers/aloop.c index d6dd4b8c750a..a1e5e7fe9c72 100644 --- a/sound/drivers/aloop.c +++ b/sound/drivers/aloop.c @@ -1130,6 +1130,8 @@ static int loopback_parse_timer_id(const char *str, } } } + if (card_idx == -1) + tid->dev_class = SNDRV_TIMER_CLASS_GLOBAL; if (!err && tid) { tid->card = card_idx; tid->device = dev; From patchwork Tue Aug 6 12:52:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Orlov X-Patchwork-Id: 13754805 Received: from mail-wm1-f43.google.com (mail-wm1-f43.google.com [209.85.128.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3A7601C4637; Tue, 6 Aug 2024 12:52:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.43 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948774; cv=none; b=C9CfQ2imLDY8JliHINLt9TTkQrQyFGqpSmxKqbuLjgLopjIY4FX8oFJQji/N1/TSt0xXXQYml21kP3azwKdtX8oKXQDCo7Hr6t9vvn5wcite5xqCYBGGPutTbFxhyczSrVwnmYV4X78UDnbAYYiEvsblUJzaK6t7ZRWJqLM3ezU= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948774; c=relaxed/simple; bh=GCNFC7auJJqaDNuW5opBT/6lfQ+oFG3olC81IwBnExI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=bkYSCza+OMCAEdQPxqZcND5r3jLmx6WQ+7kIN9gZ/VREf1whq+e8pWUh9QCWmapFxN/tlBFKscLW7f3jqUdcdgDag4S6S98W1AhQZBiYCKhbUxIsOyvThRzerGqdzl+mzvVWPl3dDmAVM3nbbRf0oHbEl83UEz1wVsB73Q1/G0A= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=CaLqlEnw; arc=none smtp.client-ip=209.85.128.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="CaLqlEnw" Received: by mail-wm1-f43.google.com with SMTP id 5b1f17b1804b1-4281da2cdaeso710925e9.2; Tue, 06 Aug 2024 05:52:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722948770; x=1723553570; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=3X+WYBsqooASrWd1IFXIS6RBNTRAxxwAyqlkCuR7pzo=; b=CaLqlEnwSDd1UWq6K6hGwObuGLs1UbG6acBOb+cZoBR9fGF1s9ii333ZfBOyIw5DGV QvrJ+FB8dBVwcxFYrT3ASjO5zMlZCtAAoywYTib+VAof95FgGl5yryMDkcaibEWG6mnh 0cvDh/Z6ofC1UCYu7U+cPoFbJlPpAn6x3ap2WrDt8/fB/z9e7rnXMQzkQ0K2icXtDRAY 3FEjmKxbbAJczois3HMrOw1xXCLfFif3KmQiZKdoX5EBLnI3+Q+Yqf53BVQLV6KCKEgv jwy7CK+73xhW5Dsc5gEyrURsllkPGhJUQUGuMLSdWR3ZwYhKdnwRlHeQ+sqYE0BAV+x/ aPRQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722948770; x=1723553570; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=3X+WYBsqooASrWd1IFXIS6RBNTRAxxwAyqlkCuR7pzo=; b=EX9+3Ff33+ZiWQ6FHI/aVPlWlX0fmTzPtV+WmlMDMKOiAh2ouRFZKXz4jX4UFRcW45 v1QSruZBxNkP1Kx1Tdh0vmjZQHT8YdGMggBB3ovuex5PVEp9Ii7Jc37fBQlUkj1d9GPf pVEhomoZ+ZN9MxptyYVuabq/Jwn3hCQWPa5/Mny/5pEMUUqzy7JHUdDkJnFFG9QOSp6O VAP/2UPfMoDqEHdJVFAda/JavXDx1k0ilZsNQBgE3oBbny8ESup1gU/83GVFDUISP2qK ssECiOoMHARsAnnxIxgLZgXDe4DqPtzVMb8hbcyBHiPVGsGYvryry2lsHh5Z/0mqLWcG Wocg== X-Forwarded-Encrypted: i=1; AJvYcCUbvd5dEQlHjsRwlQo8uz7SDWOktc7Vrq2zXAYQDCxUIMvPpV84QLRQDCiGeHFKGqYYpWhgusqBtZFvHDw=@vger.kernel.org, AJvYcCVQixp3os0QBoeNlTQDC2c9aXw74NF8/L0wxogZ41y/t3GjicWZyc/gpw6QBXYRCJkb4ZhRisZA4MaqMGdWFsOc@vger.kernel.org, AJvYcCXI45tlhUVooSg3ulaQqgE6YH8hDzl+ki9hlWV9Tvl+rnwlg0fy3kMD4USLtdrDVHCednx3oarK1T8=@vger.kernel.org, AJvYcCXpgAOAv9g/8tEAYziY2PEkRomtwzVkUsfh5c6Lr4NQqGhBZDjprkLby3AFhZBaQ4uo1erzg0VpwMenty9l@vger.kernel.org X-Gm-Message-State: AOJu0YzaOGb0vW3He9/bU6m777NNNbKtF8TqX3U/PfM8px0ALMcJIdm3 uOf21Bq/bTBJZOdfwYBrA3JEVpKIK1slpKv6JMLkdCslempPL0tC X-Google-Smtp-Source: AGHT+IGMjLgYiYdwxMuO7WLiimK30JfH+11Z4zn7OZktuSTfV7OzBfE8MFnsjVKFvIcRFOHSOQD7Bg== X-Received: by 2002:a5d:59ab:0:b0:367:9cf7:6df8 with SMTP id ffacd0b85a97d-36bbc0a002fmr6205184f8f.2.1722948770033; Tue, 06 Aug 2024 05:52:50 -0700 (PDT) Received: from ivan-HLYL-WXX9.. ([2a01:4b00:d20e:7300:b50e:24fa:fd17:c835]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-428e6d648a0sm179487255e9.10.2024.08.06.05.52.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 05:52:49 -0700 (PDT) From: Ivan Orlov To: perex@perex.cz, tiwai@suse.com, corbet@lwn.net, broonie@kernel.org, shuah@kernel.org Cc: Ivan Orlov , linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, christophe.jaillet@wanadoo.fr, aholzinger@gmx.de Subject: [PATCH v3 2/4] Docs/sound: Add documentation for userspace-driven ALSA timers Date: Tue, 6 Aug 2024 13:52:41 +0100 Message-Id: <20240806125243.449959-3-ivan.orlov0322@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240806125243.449959-1-ivan.orlov0322@gmail.com> References: <20240806125243.449959-1-ivan.orlov0322@gmail.com> Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add the documentation which describes the new userspace-driven timers API introduced in this patch series. The documentation contains: - Description of userspace-driven ALSA timers, what they are for - Description of the timers API - Example of how the timers can be created and triggered - How the timers can be used as a timer sources for snd-aloop module Suggested-by: Axel Holzinger Signed-off-by: Ivan Orlov --- V1 -> V2: - No changes V2 -> V3: - No changes Documentation/sound/index.rst | 1 + Documentation/sound/utimers.rst | 120 ++++++++++++++++++++++++++++++++ 2 files changed, 121 insertions(+) create mode 100644 Documentation/sound/utimers.rst diff --git a/Documentation/sound/index.rst b/Documentation/sound/index.rst index 7e67e12730d3..c437f2a4bc85 100644 --- a/Documentation/sound/index.rst +++ b/Documentation/sound/index.rst @@ -13,6 +13,7 @@ Sound Subsystem Documentation alsa-configuration hd-audio/index cards/index + utimers .. only:: subproject and html diff --git a/Documentation/sound/utimers.rst b/Documentation/sound/utimers.rst new file mode 100644 index 000000000000..0bd875ea9986 --- /dev/null +++ b/Documentation/sound/utimers.rst @@ -0,0 +1,120 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================= +Userspace-driven timers +======================= + +:Author: Ivan Orlov + +Preface +======= + +This document describes the userspace-driven timers: virtual ALSA timers +which could be created and controlled by userspace applications using +IOCTL calls. Such timers could be useful when synchronizing audio +stream with timer sources which we don't have ALSA timers exported for +(e.g. PTP clocks), and when synchronizing the audio stream going through +two virtual sound devices using ``snd-aloop`` (for instance, when +we have a network application sending frames to one snd-aloop device, +and another sound application listening on the other end of snd-aloop). + +Enabling userspace-driven timers +================================ + +The userspace-driven timers could be enabled in the kernel using the +``CONFIG_SND_UTIMER`` configuration option. It depends on the +``CONFIG_SND_TIMER`` option, so it also should be enabled. + +Userspace-driven timers API +=========================== + +Userspace application can create a userspace-driven ALSA timer by +executing the ``SNDRV_TIMER_IOCTL_CREATE`` ioctl call on the +``/dev/snd/timer`` device file descriptor. The ``snd_utimer_info`` +structure should be passed as an ioctl argument: + +:: + + struct snd_utimer_info { + snd_pcm_uframes_t frame_rate; + snd_pcm_uframes_t period_size; + unsigned int id; + } + +``frame_rate`` and ``period_size`` set the desired frame rate and period +size emulated by the virtual timer respectively. ``id`` field gets +overwritten by the ioctl, and the identifier you get in this field after +the call can be used as a timer subdevice number when passing the timer +to ``snd-aloop`` kernel module or other userspace applications. There +could be up to 128 userspace-driven timers in the system at one moment +of time, thus the id value ranges from 0 to 127. + +Besides from overwriting the ``snd_utimer_info`` struct, ioctl returns +a timer file descriptor, which can be used to trigger the timer. This +guarantees that the timer can only be triggered by the process which +created it. The timer then can be triggered with +``SNDRV_TIMER_IOCTL_TRIGGER`` ioctl call on the timer file descriptor. + +So, the example code for creating and triggering the timer would be: + +:: + + static const struct snd_utimer_info utimer_info = { + .frame_rate = 8000, + .period_size = 4410, + .id = -1, + }; + + int timer_device_fd = open("/dev/snd/timer", O_RDWR | O_CLOEXEC); + int utimer_fd = ioctl(timer_device_fd, SNDRV_TIMER_IOCTL_CREATE, &utimer_info); + + if (utimer_fd < 0) { + perror("Failed to create the timer"); + return -1; + } + + ... + + /* + * Now we want to trigger the timer. Callbacks of all of the + * timer instances binded to this timer will be executed after + * this call. + */ + ioctl(utimer_fd, SNDRV_TIMER_IOCTL_TRIGGER, NULL); + + ... + + /* Now, destroy the timer */ + close(utimer_fd); + + +More detailed example of creating and ticking the timer could be found +in the utimer ALSA selftest. + +Userspace-driven timers and snd-aloop +------------------------------------- + +Userspace-driven timers could be easily used with ``snd-aloop`` module +when synchronizing two sound applications on both ends of the virtual +sound loopback. For instance, if one of the applications receives sound +frames from network and sends them to snd-aloop pcm device, and another +application listens for frames on the other snd-aloop pcm device, it +makes sense that the ALSA middle layer should initiate a data +transaction when the new period of data is received through network, but +not when the certain amount of jiffies elapses. Userspace-driven ALSA +timers could be used to achieve this. + +To use userspace-driven ALSA timer as a timer source of snd-aloop, pass +the following string as the snd-aloop ``timer_source`` parameter: + +:: + + # modprobe snd-aloop timer_source="-1.4." + +Where ``utimer_id`` is the id of the timer you created with +``SNDRV_TIMER_IOCTL_CREATE``, and ``4`` is the number of +userspace-driven timers device (``SNDRV_TIMER_GLOBAL_UDRIVEN``). + +After that, each time you trigger the timer with +``SNDRV_TIMER_IOCTL_TRIGGER`` the new period of data will be transferred +from one snd-aloop device to another. From patchwork Tue Aug 6 12:52:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Orlov X-Patchwork-Id: 13754806 Received: from mail-wm1-f46.google.com (mail-wm1-f46.google.com [209.85.128.46]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 534931C579A; Tue, 6 Aug 2024 12:52:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.46 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948775; cv=none; b=M1Ht13n6msVfbctpvWi3/hJIU1ytuFvoxwE8ky7oXrpruO6yjWIM0gguR09Q5brksMgi06JuHv0/W7w1PEodrgEmXsIkR/ahuybC5Mqwo94de0x2wCsoWjS0kwKErsj1a0xYFsGJx6sQTF1Im5DmGbZpCermr1iODzr/88RPU5E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948775; c=relaxed/simple; bh=kZ/dS9zA6Yv25DR45SNBuMw11IO3/X2XTvC9C6KrC8Y=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=O4MljPYBGdvxttY8idCJ/DTGTmBEAjTMjkRP8M4KdrZwsbN7mkZgE4wfUW6cB0zVrGOhYJjrFa6iyVpjHRyMsScjxjUDetTiGBNBYF4y329NFtYuN8111rpjl7Lp7thvk5GKT3pV6wiHV/G2060QXHeDahO/elfGQBo8ymfkuiw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=QZdgCSM+; arc=none smtp.client-ip=209.85.128.46 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="QZdgCSM+" Received: by mail-wm1-f46.google.com with SMTP id 5b1f17b1804b1-4280692835dso711625e9.1; Tue, 06 Aug 2024 05:52:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722948771; x=1723553571; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=JQjmlCUBejzKZiEwYpQ1B7ebPDsGm04pP5yqUdZh+5E=; b=QZdgCSM+U2pc5nmvrluOJcORlxHuyWL1+ri3JBXEoscBTs+q4jq86ODag9dmS4Gc7Z CC+I6TdFX2R7Q4If15tdoIU9SQ384sBFcK1qfV99r7WEpxgp/2cZaD7+OF785Z2N/5Yc u/UqJ9KkzGZHtxZL62dqarw67CQjKr++JklepSXreuOZUt168SzcIY0WPGAFkGP8L4Z2 yWQucJugQlysJr/k6H6qqNJB67VUPURCAQbn8tR5kcoGtoFnhrlV/LMLBm+Lct/2EOkG sUMTppGH4gp2sy/URkwO6SptEmGSwNjuDCDo0nrcvCI/JRcjr2TEzvda9kgA5cGDUYaf 4uLA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722948771; x=1723553571; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=JQjmlCUBejzKZiEwYpQ1B7ebPDsGm04pP5yqUdZh+5E=; b=kKf4i6jyULPJnWfCh04Hyx/0iDRFGoboUDb2M3E1qrxZde71T1topDaV1rYwCGYZXs Q6Mj43cw/eG3X7+ZWsSCmMbtnHOdETvSEZIavdAlf1hMAX5xRlpBALgfN6BryeHeBfhe DAT3+9Kc/V9SKOnNp6x/NOFw583tg6XQ5Qg2e9RTvLQKhM9VS14EyEb78U8UvznBgoDF hJoEsraTCaAf83eKY+FesnXUcZLalgVL/vneTTEI06c5x+SycYrsgFKJeMPoS3Krr10n FZzwJIYrdnFxDaca1qEeCkAs+WYfFrs7W+OQp+piclfTB4UfGSonrbqk8jI3hF2I15w5 TfJA== X-Forwarded-Encrypted: i=1; AJvYcCWsfIU2Z9vXi1gYRsaGPbxhJ9yew801YaFFVWHiywKSOKS6SSnissMTuCuQg9bRBcruLDhIsQmNOT+mfDu3@vger.kernel.org, AJvYcCXUgXenIo1M827ufhc2Odl+I8ArmEqdGQ5tfuuX83rfjlmZ1+yqCQIuNWG9TsxXBeEvLDPrxrwoi/M=@vger.kernel.org, AJvYcCXZltVE4MV/qC+KHLXOMO02dLZUMKtQn0I/fLtGnZ4+yuWhDUBvQExKYBFuxLH4eVrfV2pp7Gq4uwJHTgN6ax5b@vger.kernel.org, AJvYcCXm8K8A+5i9PYgXUlliFT+rA5PgEQcxmEA2pItekozbjChrS0G/0z6gb0UVHs5/+KrlfgzQVXljYubdtg0=@vger.kernel.org X-Gm-Message-State: AOJu0YxeO7C6pqIm6LZjOHmroWDUz4T7WcXQnX2LcbVr0iJbLf+NX4Tb pL88Wmzi9k5cvxRak7Ch1lCfkXdHhSwFrJ4llXPji4SDZs9nFRaY X-Google-Smtp-Source: AGHT+IGF8+5DkZ6JTcKYMnxPdk3Wd9/3E8xsogY0Z5XLzLGUf8tGaE4fyz6gguvBT7F6a6HJEsHE3w== X-Received: by 2002:a05:600c:3592:b0:427:9f6c:e4bd with SMTP id 5b1f17b1804b1-428e6ba7ec3mr64604415e9.6.1722948771447; Tue, 06 Aug 2024 05:52:51 -0700 (PDT) Received: from ivan-HLYL-WXX9.. ([2a01:4b00:d20e:7300:b50e:24fa:fd17:c835]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-428e6d648a0sm179487255e9.10.2024.08.06.05.52.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 05:52:51 -0700 (PDT) From: Ivan Orlov To: perex@perex.cz, tiwai@suse.com, corbet@lwn.net, broonie@kernel.org, shuah@kernel.org Cc: Ivan Orlov , linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, christophe.jaillet@wanadoo.fr, aholzinger@gmx.de Subject: [PATCH v3 3/4] ALSA: timer: Introduce virtual userspace-driven timers Date: Tue, 6 Aug 2024 13:52:42 +0100 Message-Id: <20240806125243.449959-4-ivan.orlov0322@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240806125243.449959-1-ivan.orlov0322@gmail.com> References: <20240806125243.449959-1-ivan.orlov0322@gmail.com> Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement two ioctl calls in order to support virtual userspace-driven ALSA timers. The first ioctl is SNDRV_TIMER_IOCTL_CREATE, which gets the snd_utimer_info struct as a parameter and returns a file descriptor of a virtual timer. It also updates the `id` field of the snd_utimer_info struct, which provides a unique identifier for the timer (basically, the subdevice number which can be used when creating timer instances). This patch also introduces a tiny id allocator for the userspace-driven timers, which guarantees that we don't have more than 128 of them in the system. Another ioctl is SNDRV_TIMER_IOCTL_TRIGGER, which allows us to trigger the virtual timer (and calls snd_timer_interrupt for the timer under the hood), causing all of the timer instances binded to this timer to execute their callbacks. The maximum amount of ticks available for the timer is 1 for the sake of simplification of the userspace API. 'start', 'stop', 'open' and 'close' callbacks for the userspace-driven timers are empty since we don't really do any hardware initialization here. Suggested-by: Axel Holzinger Signed-off-by: Ivan Orlov --- V1 -> V2: - Add missing kfree for the utimer name in snd_utimer_free - Remove extra newline in sound core Kconfig - Use IDA allocator API to allocate utimer ids - Use kasprintf for the timer name instead of kzalloc + sprintf V2 -> V3: - Use __u64 instead of snd_pcm_uframes_t in snd_utimer_info struct - Add 16 reserved bytes to snd_utimer_info struct just in case we decide to add some other fields to this struct - Bump the timer protocol version in SNDRV_TIMER_VERSION to 2.0.8 - Make the 'snd_utimer_ids' variable static - Add sanity checks to the 'snd_utimer_create' function: 0-check for period size and frame rate, overflow and 0- checks for resolution - Use automatic cleanup in 'snd_utimer_ioctl_create' - Return -ENOTTY instead of -EINVAL from ioctl if userspace-driven timers are disabled include/uapi/sound/asound.h | 20 +++- sound/core/Kconfig | 10 ++ sound/core/timer.c | 221 ++++++++++++++++++++++++++++++++++++ 3 files changed, 250 insertions(+), 1 deletion(-) diff --git a/include/uapi/sound/asound.h b/include/uapi/sound/asound.h index 8bf7e8a0eb6f..cdd9cf8f71c1 100644 --- a/include/uapi/sound/asound.h +++ b/include/uapi/sound/asound.h @@ -869,7 +869,7 @@ struct snd_ump_block_info { * Timer section - /dev/snd/timer */ -#define SNDRV_TIMER_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 7) +#define SNDRV_TIMER_VERSION SNDRV_PROTOCOL_VERSION(2, 0, 8) enum { SNDRV_TIMER_CLASS_NONE = -1, @@ -894,6 +894,7 @@ enum { #define SNDRV_TIMER_GLOBAL_RTC 1 /* unused */ #define SNDRV_TIMER_GLOBAL_HPET 2 #define SNDRV_TIMER_GLOBAL_HRTIMER 3 +#define SNDRV_TIMER_GLOBAL_UDRIVEN 4 /* info flags */ #define SNDRV_TIMER_FLG_SLAVE (1<<0) /* cannot be controlled */ @@ -974,6 +975,21 @@ struct snd_timer_status { }; #endif +/* + * This structure describes the userspace-driven timer. Such timers are purely virtual, + * and can only be triggered from software (for instance, by userspace application). + */ +struct snd_utimer_info { + /* + * To pretend being a normal timer, we need to know the frame rate and + * the period size in frames. + */ + __u64 frame_rate; + __u64 period_size; + unsigned int id; + unsigned char reserved[16]; +}; + #define SNDRV_TIMER_IOCTL_PVERSION _IOR('T', 0x00, int) #define SNDRV_TIMER_IOCTL_NEXT_DEVICE _IOWR('T', 0x01, struct snd_timer_id) #define SNDRV_TIMER_IOCTL_TREAD_OLD _IOW('T', 0x02, int) @@ -990,6 +1006,8 @@ struct snd_timer_status { #define SNDRV_TIMER_IOCTL_CONTINUE _IO('T', 0xa2) #define SNDRV_TIMER_IOCTL_PAUSE _IO('T', 0xa3) #define SNDRV_TIMER_IOCTL_TREAD64 _IOW('T', 0xa4, int) +#define SNDRV_TIMER_IOCTL_CREATE _IOWR('T', 0xa5, struct snd_utimer_info) +#define SNDRV_TIMER_IOCTL_TRIGGER _IO('T', 0xa6) #if __BITS_PER_LONG == 64 #define SNDRV_TIMER_IOCTL_TREAD SNDRV_TIMER_IOCTL_TREAD_OLD diff --git a/sound/core/Kconfig b/sound/core/Kconfig index b970a1734647..670b26cf3065 100644 --- a/sound/core/Kconfig +++ b/sound/core/Kconfig @@ -251,6 +251,16 @@ config SND_JACK_INJECTION_DEBUG Say Y if you are debugging via jack injection interface. If unsure select "N". +config SND_UTIMER + bool "Enable support for userspace-controlled virtual timers" + depends on SND_TIMER + help + Say Y to enable the support of userspace-controlled timers. These + timers are purely virtual, and they are supposed to be triggered + from userspace. They could be quite useful when synchronizing the + sound timing with userspace applications (for instance, when sending + data through snd-aloop). + config SND_VMASTER bool diff --git a/sound/core/timer.c b/sound/core/timer.c index d104adc75a8b..dabb925625f1 100644 --- a/sound/core/timer.c +++ b/sound/core/timer.c @@ -13,6 +13,9 @@ #include #include #include +#include +#include +#include #include #include #include @@ -109,6 +112,16 @@ struct snd_timer_status64 { unsigned char reserved[64]; /* reserved */ }; +#ifdef CONFIG_SND_UTIMER +#define SNDRV_UTIMERS_MAX_COUNT 128 +/* Internal data structure for keeping the state of the userspace-driven timer */ +struct snd_utimer { + char *name; + struct snd_timer *timer; + unsigned int id; +}; +#endif + #define SNDRV_TIMER_IOCTL_STATUS64 _IOR('T', 0x14, struct snd_timer_status64) /* list of timers */ @@ -2009,6 +2022,212 @@ enum { SNDRV_TIMER_IOCTL_PAUSE_OLD = _IO('T', 0x23), }; +#ifdef CONFIG_SND_UTIMER +/* + * Since userspace-driven timers are passed to userspace, we need to have an identifier + * which will allow us to use them (basically, the subdevice number of udriven timer). + */ +static DEFINE_IDA(snd_utimer_ids); + +static void snd_utimer_put_id(struct snd_utimer *utimer) +{ + int timer_id = utimer->id; + + snd_BUG_ON(timer_id < 0 || timer_id >= SNDRV_UTIMERS_MAX_COUNT); + ida_free(&snd_utimer_ids, timer_id); +} + +static int snd_utimer_take_id(void) +{ + return ida_alloc_max(&snd_utimer_ids, SNDRV_UTIMERS_MAX_COUNT - 1, GFP_KERNEL); +} + +static void snd_utimer_free(struct snd_utimer *utimer) +{ + snd_timer_free(utimer->timer); + snd_utimer_put_id(utimer); + kfree(utimer->name); + kfree(utimer); +} + +static int snd_utimer_release(struct inode *inode, struct file *file) +{ + struct snd_utimer *utimer = (struct snd_utimer *)file->private_data; + + snd_utimer_free(utimer); + return 0; +} + +static int snd_utimer_trigger(struct file *file) +{ + struct snd_utimer *utimer = (struct snd_utimer *)file->private_data; + + snd_timer_interrupt(utimer->timer, utimer->timer->sticks); + return 0; +} + +static long snd_utimer_ioctl(struct file *file, unsigned int ioctl, unsigned long arg) +{ + switch (ioctl) { + case SNDRV_TIMER_IOCTL_TRIGGER: + return snd_utimer_trigger(file); + } + + return -ENOTTY; +} + +static const struct file_operations snd_utimer_fops = { + .llseek = noop_llseek, + .release = snd_utimer_release, + .unlocked_ioctl = snd_utimer_ioctl, +}; + +static int snd_utimer_start(struct snd_timer *t) +{ + return 0; +} + +static int snd_utimer_stop(struct snd_timer *t) +{ + return 0; +} + +static int snd_utimer_open(struct snd_timer *t) +{ + return 0; +} + +static int snd_utimer_close(struct snd_timer *t) +{ + return 0; +} + +static const struct snd_timer_hardware timer_hw = { + .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_WORK, + .open = snd_utimer_open, + .close = snd_utimer_close, + .start = snd_utimer_start, + .stop = snd_utimer_stop, +}; + +static int snd_utimer_create(struct snd_utimer_info *utimer_info, + struct snd_utimer **r_utimer) +{ + struct snd_utimer *utimer; + struct snd_timer *timer; + struct snd_timer_id tid; + int utimer_id; + int err = 0; + u64 resolution; + + if (!utimer_info || utimer_info->frame_rate == 0 || utimer_info->period_size == 0) + return -EINVAL; + + /* Let's check that we won't get an overflow in the resolution */ + if (NANO / utimer_info->frame_rate > U64_MAX / utimer_info->period_size) + return -EINVAL; + + resolution = NANO / utimer_info->frame_rate * utimer_info->period_size; + + if (resolution == 0) + return -EINVAL; + + utimer = kzalloc(sizeof(*utimer), GFP_KERNEL); + if (!utimer) + return -ENOMEM; + + /* We hold the ioctl lock here so we won't get a race condition when allocating id */ + utimer_id = snd_utimer_take_id(); + if (utimer_id < 0) { + err = utimer_id; + goto err_take_id; + } + + utimer->name = kasprintf(GFP_KERNEL, "snd-utimer%d", utimer_id); + if (!utimer->name) { + err = -ENOMEM; + goto err_get_name; + } + + utimer->id = utimer_id; + + tid.dev_sclass = SNDRV_TIMER_SCLASS_APPLICATION; + tid.dev_class = SNDRV_TIMER_CLASS_GLOBAL; + tid.card = -1; + tid.device = SNDRV_TIMER_GLOBAL_UDRIVEN; + tid.subdevice = utimer_id; + + err = snd_timer_new(NULL, utimer->name, &tid, &timer); + if (err < 0) { + pr_err("Can't create userspace-driven timer\n"); + goto err_timer_new; + } + + timer->module = THIS_MODULE; + timer->hw = timer_hw; + timer->hw.resolution = resolution; + timer->hw.ticks = 1; + timer->max_instances = MAX_SLAVE_INSTANCES; + + utimer->timer = timer; + + err = snd_timer_global_register(timer); + if (err < 0) { + pr_err("Can't register a userspace-driven timer\n"); + goto err_timer_reg; + } + + *r_utimer = utimer; + return 0; + +err_timer_reg: + snd_timer_free(timer); +err_timer_new: + kfree(utimer->name); +err_get_name: + snd_utimer_put_id(utimer); +err_take_id: + kfree(utimer); + + return err; +} + +static int snd_utimer_ioctl_create(struct file *file, + struct snd_utimer_info __user *_utimer_info) +{ + struct snd_utimer *utimer; + struct snd_utimer_info *utimer_info __free(kfree) = NULL; + int err; + + utimer_info = memdup_user(_utimer_info, sizeof(*utimer_info)); + if (IS_ERR(utimer_info)) + return PTR_ERR(no_free_ptr(utimer_info)); + + err = snd_utimer_create(utimer_info, &utimer); + if (err < 0) + return err; + + utimer_info->id = utimer->id; + + err = copy_to_user(_utimer_info, utimer_info, sizeof(*utimer_info)); + if (err) { + snd_utimer_free(utimer); + return -EFAULT; + } + + return anon_inode_getfd(utimer->name, &snd_utimer_fops, utimer, O_RDWR | O_CLOEXEC); +} + +#else + +static int snd_utimer_ioctl_create(struct file *file, + struct snd_utimer_info __user *_utimer_info) +{ + return -ENOTTY; +} + +#endif + static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd, unsigned long arg, bool compat) { @@ -2053,6 +2272,8 @@ static long __snd_timer_user_ioctl(struct file *file, unsigned int cmd, case SNDRV_TIMER_IOCTL_PAUSE: case SNDRV_TIMER_IOCTL_PAUSE_OLD: return snd_timer_user_pause(file); + case SNDRV_TIMER_IOCTL_CREATE: + return snd_utimer_ioctl_create(file, argp); } return -ENOTTY; } From patchwork Tue Aug 6 12:52:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ivan Orlov X-Patchwork-Id: 13754807 Received: from mail-wm1-f49.google.com (mail-wm1-f49.google.com [209.85.128.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 313611C688D; Tue, 6 Aug 2024 12:52:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.49 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948777; cv=none; b=G2jGpZqN7fY2vSuXdJTTjWDQmkxKF+yxVMgb348nYo5LymnKj1ARkQWH2yhagEACKOcg2Ajzl9CUpMahC8/FmSWtwB8s3mwvxHwCefoH7A7rloCY1WJvM4eAWbanB7DtWugoH4lcP3Ma4NC+ky34K04ckWRpzuPtcJfXPBAOnlY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722948777; c=relaxed/simple; bh=/55xrf/HuMLBT6TGFOESB6Qj7so2A9YjCR50+l6/JaM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Q2Y8cTE9eTpnxGfTI5y+mDdesuvTj5t91C+BoH42VBnSRVLo18WD1ucbvM0AqaPFfMdlrXS3HKBUA77WEQda/+GoJ2a/ygL0zssBesI2UhIncWhf3Jm2iUmOxlR4lRsj4/6kr+VeLKhKQlQiK/lj4NxLbuv12tO6QjN8XdFTTfU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=IKh1XZWm; arc=none smtp.client-ip=209.85.128.49 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="IKh1XZWm" Received: by mail-wm1-f49.google.com with SMTP id 5b1f17b1804b1-4281da2cdaeso711035e9.2; Tue, 06 Aug 2024 05:52:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1722948773; x=1723553573; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=jwC3+x5PmJt8tLZdNyQYdkJXkd65oNOA/vjxCPkni7k=; b=IKh1XZWm2soWkzdWnHRzvGgLpygQbq/Hq55ZBo2T9olvvbWQZUloFQFykUxjWl2S9Y XnKcT615qDxGDF+zwYOrisQtq4qbG1Ifw81LBCM5nUQg9kVfPDEZiiJYrWrgUHWrndzZ Ak3J+0guMd5S1NFh/c2JzfrA6GIbDbNvj8Ue5jZcVe2BL6HpHujxf8EQlyrMy+AV7uKo a4Ky5yYkhc7c8Mz599tZCsc2L7mlSWF8Hb1WTyxu1X7/b1fagqCsqo6gAHR21zbeMkI2 BmbElep7EuGS8mSuIctKJ9h3Dlc0cLuO5mcE6RM7joJjKxtI303hHP0fUOTYecbvf8jr 9Fbg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1722948773; x=1723553573; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=jwC3+x5PmJt8tLZdNyQYdkJXkd65oNOA/vjxCPkni7k=; b=bObXXXhKe3MA7bKebSnvFYf1VzowzWjO4vqQPThSNKIAKsh+WxyySs6bwowdPwL5Jw tyo/n1DoVLctEIO0fkB8e+ovTOOdRPYGxH59lQxyAOpK9GYL6zf5uSz8Z4ypw+ksOrUE lP/Su7x4pjxVc9aC0PpkEjkWMno47Ixe9K4UYY8FqW/ML3gRTkmrBJs5vYMcG+N2v9un i+0h+36zD46EvIcrwsawftG3QRK8JsZB114kPgSDYVUsdh01BPsZq83wif3E/C+Quzhg MknGwDqMwgDoDMVgi3i7K8PGYs2A7p63t3KUJAFqvEnRcf+FWqyi84V1thkORS8msreS GzJg== X-Forwarded-Encrypted: i=1; AJvYcCV7aiztsGby+Bvowbe7DqKJkgiH+I9AE9fZmZVwXhs9CCmd1zfEgS0nvhV8SzojgBY3UMZKq/yErPU=@vger.kernel.org, AJvYcCVBplm6LHW3a7/Q04v4JOkpWTI+LlklaW+GVqOqmbxOEh4wiNbQNpJLLBlLvnaaViCex5tUeDJXVkr5L34v@vger.kernel.org, AJvYcCVZmZx5uGcXCjPd6q5MCPcgvMx2nlnAgzbV5fYz6OKlbtliq+cUqlGOsA/5jGJdLu6AcH8HL11LXasFyUke463N@vger.kernel.org, AJvYcCVqczIJe4nYaoo1g2NtOjsJEhS6sawddiogGRrEch64YSJwbCR9XhUZ6956MZAYQBbtjNpNWzkpMZL1T10=@vger.kernel.org X-Gm-Message-State: AOJu0Yykjg5jipIITWhpj2VfyJ0WvP1sbwE0j+3xQrkCoTD/4jDqukap 9r2votB2nKg081WX7S3tlJG/u8sjEd1SkUoMQjKfXWX7kagrsP3P X-Google-Smtp-Source: AGHT+IEkEkXNKeqwp+uHF5MIDYP23+ex35LTXHBjQB29zk0y1ZqwFJXKCLAB3ZudDVib1YsoGtjHvg== X-Received: by 2002:a05:600c:1d04:b0:424:8b08:26aa with SMTP id 5b1f17b1804b1-428e6b80263mr64997365e9.3.1722948773334; Tue, 06 Aug 2024 05:52:53 -0700 (PDT) Received: from ivan-HLYL-WXX9.. ([2a01:4b00:d20e:7300:b50e:24fa:fd17:c835]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-428e6d648a0sm179487255e9.10.2024.08.06.05.52.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 06 Aug 2024 05:52:52 -0700 (PDT) From: Ivan Orlov To: perex@perex.cz, tiwai@suse.com, corbet@lwn.net, broonie@kernel.org, shuah@kernel.org Cc: Ivan Orlov , linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org, linux-sound@vger.kernel.org, linux-kernel@vger.kernel.org, christophe.jaillet@wanadoo.fr, aholzinger@gmx.de Subject: [PATCH v3 4/4] selftests: ALSA: Cover userspace-driven timers with test Date: Tue, 6 Aug 2024 13:52:43 +0100 Message-Id: <20240806125243.449959-5-ivan.orlov0322@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240806125243.449959-1-ivan.orlov0322@gmail.com> References: <20240806125243.449959-1-ivan.orlov0322@gmail.com> Precedence: bulk X-Mailing-List: linux-sound@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add a test for the new functionality of userspace-driven timers and the tool which allows us to count timer ticks in a certain time period. The test: 1. Creates a userspace-driven timer with ioctl to /dev/snd/timer 2. Starts the `global-timer` application to count the ticks of the timer from step 1. 3. Asynchronously triggers the timer multiple times with some interval 4. Compares the amount of caught ticks with the amount of trigger calls. Since we can't include and in one file due to overlapping declarations, I have to split the test into two applications: one of them counts the amount of timer ticks in the defined time period, and another one is the actual test which creates the timer, triggers it periodically and starts the first app to count the amount of ticks in a separate thread. Besides from testing the functionality itself, the test represents a sample application showing userspace-driven ALSA timers API. Signed-off-by: Ivan Orlov --- V1 -> V2: - Return NULL in the pthreaded function (ticking_func) - Process TIMER_NO_EVENT enum in the timer app output processing loop V2 -> V3: - Add new test case to cover invalid period sizes and frame rates for the userspace-driven timers (to test the sanity checks in snd_utimer_create) tools/testing/selftests/alsa/Makefile | 2 +- tools/testing/selftests/alsa/global-timer.c | 87 ++++++++++ tools/testing/selftests/alsa/utimer-test.c | 170 ++++++++++++++++++++ 3 files changed, 258 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/alsa/global-timer.c create mode 100644 tools/testing/selftests/alsa/utimer-test.c diff --git a/tools/testing/selftests/alsa/Makefile b/tools/testing/selftests/alsa/Makefile index c1ce39874e2b..0d5bd8ea900b 100644 --- a/tools/testing/selftests/alsa/Makefile +++ b/tools/testing/selftests/alsa/Makefile @@ -12,7 +12,7 @@ LDLIBS+=-lpthread OVERRIDE_TARGETS = 1 -TEST_GEN_PROGS := mixer-test pcm-test test-pcmtest-driver +TEST_GEN_PROGS := mixer-test pcm-test utimer-test test-pcmtest-driver global-timer TEST_GEN_PROGS_EXTENDED := libatest.so diff --git a/tools/testing/selftests/alsa/global-timer.c b/tools/testing/selftests/alsa/global-timer.c new file mode 100644 index 000000000000..c15ec0ba851a --- /dev/null +++ b/tools/testing/selftests/alsa/global-timer.c @@ -0,0 +1,87 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This tool is used by the utimer test, and it allows us to + * count the ticks of a global timer in a certain time frame + * (which is set by `timeout` parameter). + * + * Author: Ivan Orlov + */ +#include +#include +#include +#include + +static int ticked; +static void async_callback(snd_async_handler_t *ahandler) +{ + ticked++; +} + +static char timer_name[64]; +static void bind_to_timer(int device, int subdevice, int timeout) +{ + snd_timer_t *handle; + snd_timer_params_t *params; + snd_async_handler_t *ahandler; + + time_t end; + + sprintf(timer_name, "hw:CLASS=%d,SCLASS=%d,DEV=%d,SUBDEV=%d", + SND_TIMER_CLASS_GLOBAL, SND_TIMER_SCLASS_NONE, + device, subdevice); + + snd_timer_params_alloca(¶ms); + + if (snd_timer_open(&handle, timer_name, SND_TIMER_OPEN_NONBLOCK) < 0) { + perror("Can't open the timer"); + exit(EXIT_FAILURE); + } + + snd_timer_params_set_auto_start(params, 1); + snd_timer_params_set_ticks(params, 1); + if (snd_timer_params(handle, params) < 0) { + perror("Can't set timer params"); + exit(EXIT_FAILURE); + } + + if (snd_async_add_timer_handler(&ahandler, handle, async_callback, NULL) < 0) { + perror("Can't create a handler"); + exit(EXIT_FAILURE); + } + end = time(NULL) + timeout; + if (snd_timer_start(handle) < 0) { + perror("Failed to start the timer"); + exit(EXIT_FAILURE); + } + printf("Timer has started\n"); + while (time(NULL) <= end) { + /* + * Waiting for the timeout to elapse. Can't use sleep here, as it gets + * constantly interrupted by the signal from the timer (SIGIO) + */ + } + snd_timer_stop(handle); + snd_timer_close(handle); +} + +int main(int argc, char *argv[]) +{ + int device, subdevice, timeout; + + if (argc < 4) { + perror("Usage: %s "); + return EXIT_FAILURE; + } + + setlinebuf(stdout); + + device = atoi(argv[1]); + subdevice = atoi(argv[2]); + timeout = atoi(argv[3]); + + bind_to_timer(device, subdevice, timeout); + + printf("Total ticks count: %d\n", ticked); + + return EXIT_SUCCESS; +} diff --git a/tools/testing/selftests/alsa/utimer-test.c b/tools/testing/selftests/alsa/utimer-test.c new file mode 100644 index 000000000000..fee4d21a1955 --- /dev/null +++ b/tools/testing/selftests/alsa/utimer-test.c @@ -0,0 +1,170 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * This test covers the functionality of userspace-driven ALSA timers. Such timers + * are purely virtual (so they don't directly depend on the hardware), and they could be + * created and triggered by userspace applications. + * + * Author: Ivan Orlov + */ +#include "../kselftest_harness.h" +#include +#include +#include +#include +#include +#include +#include +#include + +#define FRAME_RATE 8000 +#define PERIOD_SIZE 4410 +#define UTIMER_DEFAULT_ID -1 +#define NANO 1000000000ULL +#define TICKS_COUNT 10 +#define TICKS_RECORDING_DELTA 5 +#define TIMER_OUTPUT_BUF_LEN 1024 +#define TIMER_FREQ_SEC 1 +#define RESULT_PREFIX_LEN strlen("Total ticks count: ") + +enum timer_app_event { + TIMER_APP_STARTED, + TIMER_APP_RESULT, + TIMER_NO_EVENT, +}; + +FIXTURE(timer_f) { + int utimer_fd; + struct snd_utimer_info *utimer_info; +}; + +FIXTURE_SETUP(timer_f) { + int timer_dev_fd; + + if (geteuid()) + SKIP(return, "This test needs root to run!"); + + self->utimer_info = calloc(1, sizeof(*self->utimer_info)); + ASSERT_NE(NULL, self->utimer_info); + + self->utimer_info->frame_rate = FRAME_RATE; + self->utimer_info->period_size = PERIOD_SIZE; + self->utimer_info->id = UTIMER_DEFAULT_ID; + + timer_dev_fd = open("/dev/snd/timer", O_RDONLY); + ASSERT_GE(timer_dev_fd, 0); + + self->utimer_fd = ioctl(timer_dev_fd, SNDRV_TIMER_IOCTL_CREATE, self->utimer_info); + ASSERT_GE(self->utimer_fd, 0); + + close(timer_dev_fd); +} + +FIXTURE_TEARDOWN(timer_f) { + close(self->utimer_fd); + free(self->utimer_info); +} + +static void *ticking_func(void *data) +{ + int i; + int *fd = (int *)data; + + for (i = 0; i < TICKS_COUNT; i++) { + /* Well, trigger the timer! */ + ioctl(*fd, SNDRV_TIMER_IOCTL_TRIGGER, NULL); + sleep(TIMER_FREQ_SEC); + } + + return NULL; +} + +static enum timer_app_event parse_timer_output(const char *s) +{ + if (strstr(s, "Timer has started")) + return TIMER_APP_STARTED; + if (strstr(s, "Total ticks count")) + return TIMER_APP_RESULT; + + return TIMER_NO_EVENT; +} + +static int parse_timer_result(const char *s) +{ + char *end; + long d; + + d = strtol(s + RESULT_PREFIX_LEN, &end, 10); + if (end == s + RESULT_PREFIX_LEN) + return -1; + + return d; +} + +/* + * This test triggers the timer and counts ticks at the same time. The amount + * of the timer trigger calls should be equal to the amount of ticks received. + */ +TEST_F(timer_f, utimer) { + char command[64]; + pthread_t ticking_thread; + int total_ticks = 0; + FILE *rfp; + char *buf = malloc(TIMER_OUTPUT_BUF_LEN); + + ASSERT_NE(buf, NULL); + + /* The timeout should be the ticks interval * count of ticks + some delta */ + sprintf(command, "./global-timer %d %d %d", SNDRV_TIMER_GLOBAL_UDRIVEN, + self->utimer_info->id, TICKS_COUNT * TIMER_FREQ_SEC + TICKS_RECORDING_DELTA); + + rfp = popen(command, "r"); + while (fgets(buf, TIMER_OUTPUT_BUF_LEN, rfp)) { + buf[TIMER_OUTPUT_BUF_LEN - 1] = 0; + switch (parse_timer_output(buf)) { + case TIMER_APP_STARTED: + /* global-timer waits for timer to trigger, so start the ticking thread */ + pthread_create(&ticking_thread, NULL, ticking_func, + &self->utimer_fd); + break; + case TIMER_APP_RESULT: + total_ticks = parse_timer_result(buf); + break; + case TIMER_NO_EVENT: + break; + } + } + pthread_join(ticking_thread, NULL); + ASSERT_EQ(total_ticks, TICKS_COUNT); + pclose(rfp); +} + +static struct snd_utimer_info wrong_timers[] = { + /* Period size is not valid (=0) */ + { .frame_rate = FRAME_RATE, .period_size = 0, .id = UTIMER_DEFAULT_ID }, + /* Frame rate is not valid (=0) */ + { .frame_rate = 0, .period_size = PERIOD_SIZE, .id = UTIMER_DEFAULT_ID }, + /* Frame rate is too high (which results in resolution = 0) */ + { .frame_rate = NANO + 1, .period_size = PERIOD_SIZE, .id = UTIMER_DEFAULT_ID }, + /* Causes overflow in resolution */ + { .frame_rate = 1, .period_size = ULONG_MAX / NANO + 1, .id = UTIMER_DEFAULT_ID }, +}; + +TEST(wrong_timers_test) { + int timer_dev_fd; + int utimer_id; + size_t i; + + timer_dev_fd = open("/dev/snd/timer", O_RDONLY); + ASSERT_GE(timer_dev_fd, 0); + + for (i = 0; i < ARRAY_SIZE(wrong_timers); i++) { + utimer_id = ioctl(timer_dev_fd, SNDRV_TIMER_IOCTL_CREATE, &wrong_timers[i]); + ASSERT_LT(utimer_id, 0); + /* Check that id was not updated */ + ASSERT_EQ(wrong_timers[i].id, UTIMER_DEFAULT_ID); + } + + close(timer_dev_fd); +} + +TEST_HARNESS_MAIN