From patchwork Wed Sep 29 03:16:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: William Breathitt Gray X-Patchwork-Id: 12524479 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B7314C433F5 for ; Wed, 29 Sep 2021 03:17:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A0EAB61352 for ; Wed, 29 Sep 2021 03:17:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243969AbhI2DS4 (ORCPT ); Tue, 28 Sep 2021 23:18:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59700 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243962AbhI2DSy (ORCPT ); Tue, 28 Sep 2021 23:18:54 -0400 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 84BB7C061746; Tue, 28 Sep 2021 20:17:14 -0700 (PDT) Received: by mail-pf1-x42b.google.com with SMTP id q23so744433pfs.9; Tue, 28 Sep 2021 20:17:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Qa5ZCeGErb5j0p2Gqn+aZhp7ud7tKxLIEmaMkDpWT38=; b=WSwhqWonIxzhiz2hIT5o4Bkl771G1ArxckUQ0wwGagp13+kfNh05CtLG8edArruzbT kxCL8eaED1mWWn8Piv0OFB3uaqwVATI0bUtipjI4c9cD1/0sf/kf6zHqLVRgfA6OEVv4 XPy1gAfNkNrv78gVhfVUBm2Lm3xntohFqywezofWZ5ccCKVDK+bwSjKUbrCMj8dVY+Yk auCxPyULEjMTkkf2or0ihA+yhjdw+T1PGPNsN3ZOvkzu5lXIg26fgLiD5zxAzGo+agzl Q0YQHSI6UIjid4kBYwHNqI7RGPdhJrRDPEVGCUGZtHE04SqEpgQLE2QHAa/Ke2xL2Zzx OPGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Qa5ZCeGErb5j0p2Gqn+aZhp7ud7tKxLIEmaMkDpWT38=; b=5qOjiwZOx9Np80Z6Y/yJD8suFuFN8iyyuNdJTInWeXNyNjfKb1PS5dk4HeU9qVrYYE A3egdfa5fJe9ooZXu27lbPerbnAM98q50NAJNkEfh/Fm9W2agOQPza3+XRzCil3ej4kt ECbWuOr3mckmwXZeN3b9b/jP73SRdbTnUE8ZlUic4MGF3+as2OjgJaSyIaPfgO16gvy8 riyQxs7fBS0dk6dZL/YUrfDxVS/JKTkkMbcvRi6jrlA+OzzTCd54UGfh2nlAyjLeqTHO R7KpXZvWkrjtYeQWh6rouUZcr1GXFx1O4+BJ/1QiZmiEfJoIkkxKigPHJAILu5Oo5nRV b1Kg== X-Gm-Message-State: AOAM5315BAD/YMGIu+9FYAvkjWCSuueJi6Abc7VWOAARnJQU8ALk1Q4d MrLP/dA5odlVxqeC0JPGwp0= X-Google-Smtp-Source: ABdhPJxpn4EftGQF+8jjmSTtCuQwegWeEb3D4qCNrylx6ekMc7l0pclEY+3TVCKYHjlRUh0cl+Dwzw== X-Received: by 2002:a63:330f:: with SMTP id z15mr7663526pgz.402.1632885434094; Tue, 28 Sep 2021 20:17:14 -0700 (PDT) Received: from localhost.localdomain ([156.146.35.76]) by smtp.gmail.com with ESMTPSA id 65sm464203pfv.210.2021.09.28.20.17.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Sep 2021 20:17:13 -0700 (PDT) From: William Breathitt Gray To: jic23@kernel.org Cc: linux-stm32@st-md-mailman.stormreply.com, kernel@pengutronix.de, a.fatoum@pengutronix.de, kamel.bouhara@bootlin.com, gwendal@chromium.org, alexandre.belloni@bootlin.com, david@lechnology.com, linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, syednwaris@gmail.com, patrick.havelange@essensium.com, fabrice.gasnier@st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@st.com, o.rempel@pengutronix.de, jarkko.nikula@linux.intel.com, William Breathitt Gray Subject: [PATCH v17 7/9] counter: Implement events_queue_size sysfs attribute Date: Wed, 29 Sep 2021 12:16:04 +0900 Message-Id: X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org The events_queue_size sysfs attribute provides a way for users to dynamically configure the Counter events queue size for the Counter character device interface. The size is in number of struct counter_event data structures. The number of elements will be rounded-up to a power of 2 due to a requirement of the kfifo_alloc function called during reallocation of the queue. Cc: Oleksij Rempel Signed-off-by: William Breathitt Gray --- Documentation/ABI/testing/sysfs-bus-counter | 8 ++++ drivers/counter/counter-sysfs.c | 45 +++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter index 0ce16669157e..06c2b3e27e0b 100644 --- a/Documentation/ABI/testing/sysfs-bus-counter +++ b/Documentation/ABI/testing/sysfs-bus-counter @@ -233,6 +233,14 @@ Description: shorter or equal to configured value are ignored. Value 0 means filter is disabled. +What: /sys/bus/counter/devices/counterX/events_queue_size +KernelVersion: 5.16 +Contact: linux-iio@vger.kernel.org +Description: + Size of the Counter events queue in number of struct + counter_event data structures. The number of elements will be + rounded-up to a power of 2. + What: /sys/bus/counter/devices/counterX/name KernelVersion: 5.2 Contact: linux-iio@vger.kernel.org diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c index 97d8d7c2a2b6..1ccd771da25f 100644 --- a/drivers/counter/counter-sysfs.c +++ b/drivers/counter/counter-sysfs.c @@ -3,11 +3,13 @@ * Generic Counter sysfs interface * Copyright (C) 2020 William Breathitt Gray */ +#include #include #include #include #include #include +#include #include #include #include @@ -783,12 +785,49 @@ static int counter_num_counts_read(struct counter_device *counter, u8 *val) return 0; } +static int counter_events_queue_size_read(struct counter_device *counter, + u64 *val) +{ + *val = kfifo_size(&counter->events); + return 0; +} + +static int counter_events_queue_size_write(struct counter_device *counter, + u64 val) +{ + DECLARE_KFIFO_PTR(events, struct counter_event); + int err = 0; + + /* Ensure chrdev is not opened more than 1 at a time */ + if (!atomic_add_unless(&counter->chrdev_lock, 1, 1)) + return -EBUSY; + + /* Allocate new events queue */ + err = kfifo_alloc(&events, val, GFP_KERNEL); + if (err) + goto exit_early; + + /* Swap in new events queue */ + kfifo_free(&counter->events); + counter->events.kfifo = events.kfifo; + +exit_early: + atomic_dec(&counter->chrdev_lock); + + return err; +} + static struct counter_comp counter_num_signals_comp = COUNTER_COMP_DEVICE_U8("num_signals", counter_num_signals_read, NULL); static struct counter_comp counter_num_counts_comp = COUNTER_COMP_DEVICE_U8("num_counts", counter_num_counts_read, NULL); +static struct counter_comp counter_events_queue_size_comp = + COUNTER_COMP_DEVICE_U64("events_queue_size", + counter_events_queue_size_read, + counter_events_queue_size_write); + static int counter_sysfs_attr_add(struct counter_device *const counter, struct counter_attribute_group *cattr_group) { @@ -827,6 +866,12 @@ static int counter_sysfs_attr_add(struct counter_device *const counter, if (err < 0) return err; + /* Create events_queue_size attribute */ + err = counter_attr_create(dev, cattr_group, + &counter_events_queue_size_comp, scope, NULL); + if (err < 0) + return err; + /* Create an attribute for each extension */ for (i = 0; i < counter->num_ext; i++) { ext = &counter->ext[i];