From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18403C19F35 for ; Fri, 27 Aug 2021 03:49:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F31F660EE7 for ; Fri, 27 Aug 2021 03:49:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244303AbhH0DuC (ORCPT ); Thu, 26 Aug 2021 23:50:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244294AbhH0Dtk (ORCPT ); Thu, 26 Aug 2021 23:49:40 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D969FC0613C1; Thu, 26 Aug 2021 20:48:51 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id a21so4561403pfh.5; Thu, 26 Aug 2021 20:48:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rpFgvWexpr5TUt4uYLLJWYsMAuhdoHGyZdgfhuMD/xI=; b=iw22K5VUNIdEw2EVWaJwsla2WuMr8Qt3WtFS0PxxXx0QQOpKeKsF+mUGAulM0aEMe9 x0GOGnfCCX6HmQFehhWUzECMIOLgImlpSbj8J1F+rJw7+iuc33s6A3OZkGlOTCYJbqav bqz7Mll4/D7Jygsl/nl+TSbpztTSiVonT85L0jMCAaHkfHIIfM5R9BlPEDOVirVzllP/ 7U1FBYngTjpJuNJWLK6EbPNqPz8rafHbyfdp5lyUFVW34C25ItPBvnaamNypHDaKAT3F 8KcH6w2bw6npV/pOP6ClNWaFyIfPJPh68ai4vT9YqftIrrvXbuAviBaDEKolGMn4ukKT MGIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rpFgvWexpr5TUt4uYLLJWYsMAuhdoHGyZdgfhuMD/xI=; b=gS2oow/gaSPQl+9Z63oeIxdgV3SZMn+Ge9Qqx5TuRm+MEaAAuiTqVd7Js3+cAMtNpa xwvOgJC92SPO9TolUJQrZgVqggyMvA56EY2/YHP98CzPO4YDoQV1j8v0o8fO+/E4go84 tA0KuTmpPRM4jhcnbOazFSJ/A+tuam//eMR/24+p7Yl606Lo+w4FCOm23gOAgm22Rw+7 vdZS+YcpaZdhU6xu//DoJyhetGE9eoM/PwUT5LZGhlug6D3Bx01FVsyN1gQALOuI71iL QUdnWPcTaKOfnnkCL4FFObkTm42jmNh6uEfv1Ld2HPPM/n925shaNzOt+qIB1hRm2duV wUrA== X-Gm-Message-State: AOAM533EkAln0lr0AIAIhiqqBKBwxG86cUibhQnvPhZWwyl+LKEwBnn9 yuvcPi5wU9bWoZbyq1DJUqM= X-Google-Smtp-Source: ABdhPJynoDva3WTpIba9QxG065TubcdooSh47MK6bPRXHbXYZxH06CMBEuYimo97wY5crXmpFXnWWw== X-Received: by 2002:a63:1a46:: with SMTP id a6mr6093244pgm.226.1630036131299; Thu, 26 Aug 2021 20:48:51 -0700 (PDT) Received: from localhost.localdomain ([156.146.35.76]) by smtp.gmail.com with ESMTPSA id o6sm4364693pjk.4.2021.08.26.20.48.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 26 Aug 2021 20:48:50 -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 , Dan Carpenter Subject: [PATCH v16 07/14] counter: Add character device interface Date: Fri, 27 Aug 2021 12:47:51 +0900 Message-Id: <422c765c91d060cdebc4f17f7aeb255d9c1a4e16.1630031207.git.vilhelm.gray@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch introduces a character device interface for the Counter subsystem. Device data is exposed through standard character device read operations. Device data is gathered when a Counter event is pushed by the respective Counter device driver. Configuration is handled via ioctl operations on the respective Counter character device node. Cc: David Lechner Cc: Gwendal Grignou Cc: Dan Carpenter Cc: Oleksij Rempel Signed-off-by: William Breathitt Gray --- drivers/counter/Makefile | 2 +- drivers/counter/counter-chrdev.c | 553 +++++++++++++++++++++++++++++++ drivers/counter/counter-chrdev.h | 14 + drivers/counter/counter-core.c | 60 +++- include/linux/counter.h | 51 +++ include/uapi/linux/counter.h | 98 ++++++ 6 files changed, 770 insertions(+), 8 deletions(-) create mode 100644 drivers/counter/counter-chrdev.c create mode 100644 drivers/counter/counter-chrdev.h diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile index 1ab7e087fdc2..8fde6c100ebc 100644 --- a/drivers/counter/Makefile +++ b/drivers/counter/Makefile @@ -4,7 +4,7 @@ # obj-$(CONFIG_COUNTER) += counter.o -counter-y := counter-core.o counter-sysfs.o +counter-y := counter-core.o counter-sysfs.o counter-chrdev.o obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o obj-$(CONFIG_INTERRUPT_CNT) += interrupt-cnt.o diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c new file mode 100644 index 000000000000..30659b67d8f3 --- /dev/null +++ b/drivers/counter/counter-chrdev.c @@ -0,0 +1,553 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic Counter character device interface + * Copyright (C) 2020 William Breathitt Gray + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "counter-chrdev.h" + +struct counter_comp_node { + struct list_head l; + struct counter_component component; + struct counter_comp comp; + void *parent; +}; + +static ssize_t counter_chrdev_read(struct file *filp, char __user *buf, + size_t len, loff_t *f_ps) +{ + struct counter_device *const counter = filp->private_data; + int err; + unsigned int copied; + + if (!counter->ops) + return -ENODEV; + + if (len < sizeof(struct counter_event)) + return -EINVAL; + + do { + if (kfifo_is_empty(&counter->events)) { + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + + err = wait_event_interruptible(counter->events_wait, + !kfifo_is_empty(&counter->events) || + !counter->ops); + if (err < 0) + return err; + if (!counter->ops) + return -ENODEV; + } + + if (mutex_lock_interruptible(&counter->events_lock)) + return -ERESTARTSYS; + err = kfifo_to_user(&counter->events, buf, len, &copied); + mutex_unlock(&counter->events_lock); + if (err < 0) + return err; + } while (!copied); + + return copied; +} + +static __poll_t counter_chrdev_poll(struct file *filp, + struct poll_table_struct *pollt) +{ + struct counter_device *const counter = filp->private_data; + __poll_t events = 0; + + if (!counter->ops) + return events; + + poll_wait(filp, &counter->events_wait, pollt); + + if (!kfifo_is_empty(&counter->events)) + events = EPOLLIN | EPOLLRDNORM; + + return events; +} + +static void counter_events_list_free(struct list_head *const events_list) +{ + struct counter_event_node *p, *n; + struct counter_comp_node *q, *o; + + list_for_each_entry_safe(p, n, events_list, l) { + /* Free associated component nodes */ + list_for_each_entry_safe(q, o, &p->comp_list, l) { + list_del(&q->l); + kfree(q); + } + + /* Free event node */ + list_del(&p->l); + kfree(p); + } +} + +static int counter_set_event_node(struct counter_device *const counter, + struct counter_watch *const watch, + const struct counter_comp_node *const cfg) +{ + struct counter_event_node *event_node; + int err = 0; + struct counter_comp_node *comp_node; + + /* Search for event in the list */ + list_for_each_entry(event_node, &counter->next_events_list, l) + if (event_node->event == watch->event && + event_node->channel == watch->channel) + break; + + /* If event is not already in the list */ + if (&event_node->l == &counter->next_events_list) { + /* Allocate new event node */ + event_node = kmalloc(sizeof(*event_node), GFP_KERNEL); + if (!event_node) + return -ENOMEM; + + /* Configure event node and add to the list */ + event_node->event = watch->event; + event_node->channel = watch->channel; + INIT_LIST_HEAD(&event_node->comp_list); + list_add(&event_node->l, &counter->next_events_list); + } + + /* Check if component watch has already been set before */ + list_for_each_entry(comp_node, &event_node->comp_list, l) + if (comp_node->parent == cfg->parent && + comp_node->comp.count_u8_read == cfg->comp.count_u8_read) { + err = -EINVAL; + goto exit_free_event_node; + } + + /* Allocate component node */ + comp_node = kmalloc(sizeof(*comp_node), GFP_KERNEL); + if (!comp_node) { + err = -ENOMEM; + goto exit_free_event_node; + } + *comp_node = *cfg; + + /* Add component node to event node */ + list_add_tail(&comp_node->l, &event_node->comp_list); + +exit_free_event_node: + /* Free event node if no one else is watching */ + if (list_empty(&event_node->comp_list)) { + list_del(&event_node->l); + kfree(event_node); + } + + return err; +} + +static int counter_enable_events(struct counter_device *const counter) +{ + unsigned long flags; + int err = 0; + + mutex_lock(&counter->n_events_list_lock); + spin_lock_irqsave(&counter->events_list_lock, flags); + + counter_events_list_free(&counter->events_list); + list_replace_init(&counter->next_events_list, + &counter->events_list); + + if (counter->ops->events_configure) + err = counter->ops->events_configure(counter); + + spin_unlock_irqrestore(&counter->events_list_lock, flags); + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static int counter_disable_events(struct counter_device *const counter) +{ + unsigned long flags; + int err = 0; + + spin_lock_irqsave(&counter->events_list_lock, flags); + + counter_events_list_free(&counter->events_list); + + if (counter->ops->events_configure) + err = counter->ops->events_configure(counter); + + spin_unlock_irqrestore(&counter->events_list_lock, flags); + + mutex_lock(&counter->n_events_list_lock); + + counter_events_list_free(&counter->next_events_list); + + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static int counter_add_watch(struct counter_device *const counter, + const unsigned long arg) +{ + void __user *const uwatch = (void __user *)arg; + struct counter_watch watch; + struct counter_comp_node comp_node = {}; + size_t parent, id; + struct counter_comp *ext; + size_t num_ext; + int err = 0; + + if (copy_from_user(&watch, uwatch, sizeof(watch))) + return -EFAULT; + + if (watch.component.type == COUNTER_COMPONENT_NONE) + goto no_component; + + parent = watch.component.parent; + + /* Configure parent component info for comp node */ + switch (watch.component.scope) { + case COUNTER_SCOPE_DEVICE: + ext = counter->ext; + num_ext = counter->num_ext; + break; + case COUNTER_SCOPE_SIGNAL: + if (parent >= counter->num_signals) + return -EINVAL; + parent = array_index_nospec(parent, counter->num_signals); + + comp_node.parent = counter->signals + parent; + + ext = counter->signals[parent].ext; + num_ext = counter->signals[parent].num_ext; + break; + case COUNTER_SCOPE_COUNT: + if (parent >= counter->num_counts) + return -EINVAL; + parent = array_index_nospec(parent, counter->num_counts); + + comp_node.parent = counter->counts + parent; + + ext = counter->counts[parent].ext; + num_ext = counter->counts[parent].num_ext; + break; + default: + return -EINVAL; + } + + id = watch.component.id; + + /* Configure component info for comp node */ + switch (watch.component.type) { + case COUNTER_COMPONENT_SIGNAL: + if (watch.component.scope != COUNTER_SCOPE_SIGNAL) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL; + comp_node.comp.signal_u32_read = counter->ops->signal_read; + break; + case COUNTER_COMPONENT_COUNT: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_U64; + comp_node.comp.count_u64_read = counter->ops->count_read; + break; + case COUNTER_COMPONENT_FUNCTION: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_FUNCTION; + comp_node.comp.count_u32_read = counter->ops->function_read; + break; + case COUNTER_COMPONENT_SYNAPSE_ACTION: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + if (id >= counter->counts[parent].num_synapses) + return -EINVAL; + id = array_index_nospec(id, counter->counts[parent].num_synapses); + + comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION; + comp_node.comp.action_read = counter->ops->action_read; + comp_node.comp.priv = counter->counts[parent].synapses + id; + break; + case COUNTER_COMPONENT_EXTENSION: + if (id >= num_ext) + return -EINVAL; + id = array_index_nospec(id, num_ext); + + comp_node.comp = ext[id]; + break; + default: + return -EINVAL; + } + /* Check if any read callback is set; this is part of a union */ + if (!comp_node.comp.count_u8_read) + return -EOPNOTSUPP; + +no_component: + mutex_lock(&counter->n_events_list_lock); + + if (counter->ops->watch_validate) { + err = counter->ops->watch_validate(counter, &watch); + if (err < 0) + goto err_exit; + } + + comp_node.component = watch.component; + + err = counter_set_event_node(counter, &watch, &comp_node); + +err_exit: + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct counter_device *const counter = filp->private_data; + int ret = -ENODEV; + + mutex_lock(&counter->ops_exist_lock); + + if (!counter->ops) + goto out_unlock; + + switch (cmd) { + case COUNTER_ADD_WATCH_IOCTL: + ret = counter_add_watch(counter, arg); + break; + case COUNTER_ENABLE_EVENTS_IOCTL: + ret = counter_enable_events(counter); + break; + case COUNTER_DISABLE_EVENTS_IOCTL: + ret = counter_disable_events(counter); + break; + default: + ret = -ENOIOCTLCMD; + break; + } + +out_unlock: + mutex_unlock(&counter->ops_exist_lock); + + return ret; +} + +static int counter_chrdev_open(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = container_of(inode->i_cdev, + typeof(*counter), + chrdev); + + if (test_and_set_bit_lock(0, counter->chrdev_lock)) + return -EBUSY; + + get_device(&counter->dev); + filp->private_data = counter; + + return nonseekable_open(inode, filp); +} + +static int counter_chrdev_release(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = filp->private_data; + int ret = 0; + + mutex_lock(&counter->ops_exist_lock); + + if (!counter->ops) { + counter_events_list_free(&counter->events_list); + counter_events_list_free(&counter->next_events_list); + ret = -ENODEV; + goto out_unlock; + } + + ret = counter_disable_events(counter); + if (ret < 0) { + mutex_unlock(&counter->ops_exist_lock); + return ret; + } + +out_unlock: + mutex_unlock(&counter->ops_exist_lock); + + put_device(&counter->dev); + clear_bit_unlock(0, counter->chrdev_lock); + + return ret; +} + +static const struct file_operations counter_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read = counter_chrdev_read, + .poll = counter_chrdev_poll, + .unlocked_ioctl = counter_chrdev_ioctl, + .open = counter_chrdev_open, + .release = counter_chrdev_release, +}; + +int counter_chrdev_add(struct counter_device *const counter) +{ + /* Initialize Counter events lists */ + INIT_LIST_HEAD(&counter->events_list); + INIT_LIST_HEAD(&counter->next_events_list); + spin_lock_init(&counter->events_list_lock); + mutex_init(&counter->n_events_list_lock); + init_waitqueue_head(&counter->events_wait); + mutex_init(&counter->events_lock); + + /* Initialize character device */ + clear_bit(0, counter->chrdev_lock); + cdev_init(&counter->chrdev, &counter_fops); + + /* Allocate Counter events queue */ + return kfifo_alloc(&counter->events, 64, GFP_KERNEL); +} + +void counter_chrdev_remove(struct counter_device *const counter) +{ + kfifo_free(&counter->events); +} + +static int counter_get_data(struct counter_device *const counter, + const struct counter_comp_node *const comp_node, + u64 *const value) +{ + const struct counter_comp *const comp = &comp_node->comp; + void *const parent = comp_node->parent; + u8 value_u8 = 0; + u32 value_u32 = 0; + int ret; + + if (comp_node->component.type == COUNTER_COMPONENT_NONE) + return 0; + + switch (comp->type) { + case COUNTER_COMP_U8: + case COUNTER_COMP_BOOL: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + ret = comp->device_u8_read(counter, &value_u8); + break; + case COUNTER_SCOPE_SIGNAL: + ret = comp->signal_u8_read(counter, parent, &value_u8); + break; + case COUNTER_SCOPE_COUNT: + ret = comp->count_u8_read(counter, parent, &value_u8); + break; + } + *value = value_u8; + return ret; + case COUNTER_COMP_SIGNAL_LEVEL: + case COUNTER_COMP_FUNCTION: + case COUNTER_COMP_ENUM: + case COUNTER_COMP_COUNT_DIRECTION: + case COUNTER_COMP_COUNT_MODE: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + ret = comp->device_u32_read(counter, &value_u32); + break; + case COUNTER_SCOPE_SIGNAL: + ret = comp->signal_u32_read(counter, parent, + &value_u32); + break; + case COUNTER_SCOPE_COUNT: + ret = comp->count_u32_read(counter, parent, &value_u32); + break; + } + *value = value_u32; + return ret; + case COUNTER_COMP_U64: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + return comp->device_u64_read(counter, value); + case COUNTER_SCOPE_SIGNAL: + return comp->signal_u64_read(counter, parent, value); + case COUNTER_SCOPE_COUNT: + return comp->count_u64_read(counter, parent, value); + default: + return -EINVAL; + } + case COUNTER_COMP_SYNAPSE_ACTION: + ret = comp->action_read(counter, parent, comp->priv, + &value_u32); + *value = value_u32; + return ret; + default: + return -EINVAL; + } +} + +/** + * counter_push_event - queue event for userspace reading + * @counter: pointer to Counter structure + * @event: triggered event + * @channel: event channel + * + * Note: If no one is watching for the respective event, it is silently + * discarded. + */ +void counter_push_event(struct counter_device *const counter, const u8 event, + const u8 channel) +{ + struct counter_event ev; + unsigned int copied = 0; + unsigned long flags; + struct counter_event_node *event_node; + struct counter_comp_node *comp_node; + + ev.timestamp = ktime_get_ns(); + ev.watch.event = event; + ev.watch.channel = channel; + + /* Could be in an interrupt context, so use a spin lock */ + spin_lock_irqsave(&counter->events_list_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_node, &counter->events_list, l) + if (event_node->event == event && + event_node->channel == channel) + break; + + /* If event is not in the list */ + if (&event_node->l == &counter->events_list) + goto exit_early; + + /* Read and queue relevant comp for userspace */ + list_for_each_entry(comp_node, &event_node->comp_list, l) { + ev.watch.component = comp_node->component; + ev.status = -counter_get_data(counter, comp_node, &ev.value); + + copied += kfifo_in(&counter->events, &ev, 1); + } + +exit_early: + spin_unlock_irqrestore(&counter->events_list_lock, flags); + + if (copied) + wake_up_poll(&counter->events_wait, EPOLLIN); +} +EXPORT_SYMBOL_GPL(counter_push_event); diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h new file mode 100644 index 000000000000..5529d16703c4 --- /dev/null +++ b/drivers/counter/counter-chrdev.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Counter character device interface + * Copyright (C) 2020 William Breathitt Gray + */ +#ifndef _COUNTER_CHRDEV_H_ +#define _COUNTER_CHRDEV_H_ + +#include + +int counter_chrdev_add(struct counter_device *const counter); +void counter_chrdev_remove(struct counter_device *const counter); + +#endif /* _COUNTER_CHRDEV_H_ */ diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c index 3cda2c47bacb..28dc1ff63c94 100644 --- a/drivers/counter/counter-core.c +++ b/drivers/counter/counter-core.c @@ -3,14 +3,22 @@ * Generic Counter interface * Copyright (C) 2020 William Breathitt Gray */ +#include #include #include +#include #include +#include #include #include #include +#include #include +#include +#include +#include +#include "counter-chrdev.h" #include "counter-sysfs.h" /* Provides a unique ID for each counter device */ @@ -18,6 +26,9 @@ static DEFINE_IDA(counter_ida); static void counter_device_release(struct device *dev) { + struct counter_device *const counter = dev_get_drvdata(dev); + + counter_chrdev_remove(counter); ida_free(&counter_ida, dev->id); } @@ -31,6 +42,8 @@ static struct bus_type counter_bus_type = { .dev_name = "counter", }; +static dev_t counter_devt; + /** * counter_register - register Counter to the system * @counter: pointer to Counter to register @@ -53,10 +66,13 @@ int counter_register(struct counter_device *const counter) if (id < 0) return id; + mutex_init(&counter->ops_exist_lock); + /* Configure device structure for Counter */ dev->id = id; dev->type = &counter_device_type; dev->bus = &counter_bus_type; + dev->devt = MKDEV(MAJOR(counter_devt), id); if (counter->parent) { dev->parent = counter->parent; dev->of_node = counter->parent->of_node; @@ -64,18 +80,22 @@ int counter_register(struct counter_device *const counter) device_initialize(dev); dev_set_drvdata(dev, counter); - /* Add Counter sysfs attributes */ - err = counter_sysfs_add(counter); + err = counter_chrdev_add(counter); if (err < 0) goto err_free_id; - /* Add device to system */ - err = device_add(dev); + err = counter_sysfs_add(counter); if (err < 0) - goto err_free_id; + goto err_remove_chrdev; + + err = cdev_device_add(&counter->chrdev, dev); + if (err < 0) + goto err_remove_chrdev; return 0; +err_remove_chrdev: + counter_chrdev_remove(counter); err_free_id: put_device(dev); return err; @@ -93,7 +113,16 @@ void counter_unregister(struct counter_device *const counter) if (!counter) return; - device_unregister(&counter->dev); + cdev_device_del(&counter->chrdev, &counter->dev); + + mutex_lock(&counter->ops_exist_lock); + + counter->ops = NULL; + wake_up(&counter->events_wait); + + mutex_unlock(&counter->ops_exist_lock); + + put_device(&counter->dev); } EXPORT_SYMBOL_GPL(counter_unregister); @@ -127,13 +156,30 @@ int devm_counter_register(struct device *dev, } EXPORT_SYMBOL_GPL(devm_counter_register); +#define COUNTER_DEV_MAX 256 + static int __init counter_init(void) { - return bus_register(&counter_bus_type); + int err; + + err = bus_register(&counter_bus_type); + if (err < 0) + return err; + + err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter"); + if (err < 0) + goto err_unregister_bus; + + return 0; + +err_unregister_bus: + bus_unregister(&counter_bus_type); + return err; } static void __exit counter_exit(void) { + unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX); bus_unregister(&counter_bus_type); } diff --git a/include/linux/counter.h b/include/linux/counter.h index 7c9f7e23953a..9c9984655f8c 100644 --- a/include/linux/counter.h +++ b/include/linux/counter.h @@ -6,9 +6,14 @@ #ifndef _COUNTER_H_ #define _COUNTER_H_ +#include #include #include +#include +#include +#include #include +#include #include struct counter_device; @@ -199,6 +204,20 @@ struct counter_count { size_t num_ext; }; +/** + * struct counter_event_node - Counter Event node + * @l: list of current watching Counter events + * @event: event that triggers + * @channel: event channel + * @comp_list: list of components to watch when event triggers + */ +struct counter_event_node { + struct list_head l; + u8 event; + u8 channel; + struct list_head comp_list; +}; + /** * struct counter_ops - Callbacks from driver * @signal_read: optional read callback for Signals. The read level of @@ -222,6 +241,13 @@ struct counter_count { * @action_write: optional write callback for Synapse action modes. The * action mode to write for the respective Synapse is * passed in via the action parameter. + * @events_configure: optional write callback to configure events. The list of + * struct counter_event_node may be accessed via the + * events_list member of the counter parameter. + * @watch_validate: optional callback to validate a watch. The Counter + * component watch configuration is passed in via the watch + * parameter. A return value of 0 indicates a valid Counter + * component watch configuration. */ struct counter_ops { int (*signal_read)(struct counter_device *counter, @@ -245,6 +271,9 @@ struct counter_ops { struct counter_count *count, struct counter_synapse *synapse, enum counter_synapse_action action); + int (*events_configure)(struct counter_device *counter); + int (*watch_validate)(struct counter_device *counter, + const struct counter_watch *watch); }; /** @@ -260,6 +289,16 @@ struct counter_ops { * @num_ext: number of Counter device extensions specified in @ext * @priv: optional private data supplied by driver * @dev: internal device structure + * @chrdev: internal character device structure + * @events_list: list of current watching Counter events + * @events_list_lock: lock to protect Counter events list operations + * @next_events_list: list of next watching Counter events + * @n_events_list_lock: lock to protect Counter next events list operations + * @events: queue of detected Counter events + * @events_wait: wait queue to allow blocking reads of Counter events + * @events_lock: lock to protect Counter events queue read operations + * @chrdev_lock: lock to limit chrdev to a single open at a time + * @ops_exist_lock: lock to prevent use during removal */ struct counter_device { const char *name; @@ -278,12 +317,24 @@ struct counter_device { void *priv; struct device dev; + struct cdev chrdev; + struct list_head events_list; + spinlock_t events_list_lock; + struct list_head next_events_list; + struct mutex n_events_list_lock; + DECLARE_KFIFO_PTR(events, struct counter_event); + wait_queue_head_t events_wait; + struct mutex events_lock; + DECLARE_BITMAP(chrdev_lock, 1); + struct mutex ops_exist_lock; }; int counter_register(struct counter_device *const counter); void counter_unregister(struct counter_device *const counter); int devm_counter_register(struct device *dev, struct counter_device *const counter); +void counter_push_event(struct counter_device *const counter, const u8 event, + const u8 channel); #define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \ { \ diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h index 6113938a6044..d0aa95aeff7b 100644 --- a/include/uapi/linux/counter.h +++ b/include/uapi/linux/counter.h @@ -6,6 +6,19 @@ #ifndef _UAPI_COUNTER_H_ #define _UAPI_COUNTER_H_ +#include +#include + +/* Component type definitions */ +enum counter_component_type { + COUNTER_COMPONENT_NONE, + COUNTER_COMPONENT_SIGNAL, + COUNTER_COMPONENT_COUNT, + COUNTER_COMPONENT_FUNCTION, + COUNTER_COMPONENT_SYNAPSE_ACTION, + COUNTER_COMPONENT_EXTENSION, +}; + /* Component scope definitions */ enum counter_scope { COUNTER_SCOPE_DEVICE, @@ -13,6 +26,91 @@ enum counter_scope { COUNTER_SCOPE_COUNT, }; +/** + * struct counter_component - Counter component identification + * @type: component type (one of enum counter_component_type) + * @scope: component scope (one of enum counter_scope) + * @parent: parent ID (matching the ID suffix of the respective parent sysfs + * path as described by the ABI documentation file + * Documentation/ABI/testing/sysfs-bus-counter) + * @id: component ID (matching the ID provided by the respective *_component_id + * sysfs attribute of the desired component) + * + * For example, if the Count 2 ceiling extension of Counter device 4 is desired, + * set type equal to COUNTER_COMPONENT_EXTENSION, scope equal to + * COUNTER_COUNT_SCOPE, parent equal to 2, and id equal to the value provided by + * the respective /sys/bus/counter/devices/counter4/count2/ceiling_component_id + * sysfs attribute. + */ +struct counter_component { + __u8 type; + __u8 scope; + __u8 parent; + __u8 id; +}; + +/* Event type definitions */ +enum counter_event_type { + /* Count value increased past ceiling */ + COUNTER_EVENT_OVERFLOW, + /* Count value decreased past floor */ + COUNTER_EVENT_UNDERFLOW, + /* Count value increased past ceiling, or decreased past floor */ + COUNTER_EVENT_OVERFLOW_UNDERFLOW, + /* Count value reached threshold */ + COUNTER_EVENT_THRESHOLD, + /* Index signal detected */ + COUNTER_EVENT_INDEX, +}; + +/** + * struct counter_watch - Counter component watch configuration + * @component: component to watch when event triggers + * @event: event that triggers (one of enum counter_event_type) + * @channel: event channel (typically 0 unless the device supports concurrent + * events of the same type) + */ +struct counter_watch { + struct counter_component component; + __u8 event; + __u8 channel; +}; + +/* + * Queues a Counter watch for the specified event. + * + * The queued watches will not be applied until COUNTER_ENABLE_EVENTS_IOCTL is + * called. + */ +#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch) +/* + * Enables monitoring the events specified by the Counter watches that were + * queued by COUNTER_ADD_WATCH_IOCTL. + * + * If events are already enabled, the new set of watches replaces the old one. + * Calling this ioctl also has the effect of clearing the queue of watches added + * by COUNTER_ADD_WATCH_IOCTL. + */ +#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01) +/* + * Stops monitoring the previously enabled events. + */ +#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02) + +/** + * struct counter_event - Counter event data + * @timestamp: best estimate of time of event occurrence, in nanoseconds + * @value: component value + * @watch: component watch configuration + * @status: return status (system error number) + */ +struct counter_event { + __aligned_u64 timestamp; + __aligned_u64 value; + struct counter_watch watch; + __u8 status; +}; + /* Count direction values */ enum counter_count_direction { COUNTER_COUNT_DIRECTION_FORWARD, -- 2.32.0 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEDBCC432BE for ; Fri, 27 Aug 2021 03:52:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BD8F560EE7 for ; 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Thu, 26 Aug 2021 20:48:50 -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 , Dan Carpenter Subject: [PATCH v16 07/14] counter: Add character device interface Date: Fri, 27 Aug 2021 12:47:51 +0900 Message-Id: <422c765c91d060cdebc4f17f7aeb255d9c1a4e16.1630031207.git.vilhelm.gray@gmail.com> X-Mailer: git-send-email 2.33.0 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210826_204851_977469_754712E9 X-CRM114-Status: GOOD ( 31.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org This patch introduces a character device interface for the Counter subsystem. Device data is exposed through standard character device read operations. Device data is gathered when a Counter event is pushed by the respective Counter device driver. Configuration is handled via ioctl operations on the respective Counter character device node. Cc: David Lechner Cc: Gwendal Grignou Cc: Dan Carpenter Cc: Oleksij Rempel Signed-off-by: William Breathitt Gray --- drivers/counter/Makefile | 2 +- drivers/counter/counter-chrdev.c | 553 +++++++++++++++++++++++++++++++ drivers/counter/counter-chrdev.h | 14 + drivers/counter/counter-core.c | 60 +++- include/linux/counter.h | 51 +++ include/uapi/linux/counter.h | 98 ++++++ 6 files changed, 770 insertions(+), 8 deletions(-) create mode 100644 drivers/counter/counter-chrdev.c create mode 100644 drivers/counter/counter-chrdev.h diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile index 1ab7e087fdc2..8fde6c100ebc 100644 --- a/drivers/counter/Makefile +++ b/drivers/counter/Makefile @@ -4,7 +4,7 @@ # obj-$(CONFIG_COUNTER) += counter.o -counter-y := counter-core.o counter-sysfs.o +counter-y := counter-core.o counter-sysfs.o counter-chrdev.o obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o obj-$(CONFIG_INTERRUPT_CNT) += interrupt-cnt.o diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c new file mode 100644 index 000000000000..30659b67d8f3 --- /dev/null +++ b/drivers/counter/counter-chrdev.c @@ -0,0 +1,553 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Generic Counter character device interface + * Copyright (C) 2020 William Breathitt Gray + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "counter-chrdev.h" + +struct counter_comp_node { + struct list_head l; + struct counter_component component; + struct counter_comp comp; + void *parent; +}; + +static ssize_t counter_chrdev_read(struct file *filp, char __user *buf, + size_t len, loff_t *f_ps) +{ + struct counter_device *const counter = filp->private_data; + int err; + unsigned int copied; + + if (!counter->ops) + return -ENODEV; + + if (len < sizeof(struct counter_event)) + return -EINVAL; + + do { + if (kfifo_is_empty(&counter->events)) { + if (filp->f_flags & O_NONBLOCK) + return -EAGAIN; + + err = wait_event_interruptible(counter->events_wait, + !kfifo_is_empty(&counter->events) || + !counter->ops); + if (err < 0) + return err; + if (!counter->ops) + return -ENODEV; + } + + if (mutex_lock_interruptible(&counter->events_lock)) + return -ERESTARTSYS; + err = kfifo_to_user(&counter->events, buf, len, &copied); + mutex_unlock(&counter->events_lock); + if (err < 0) + return err; + } while (!copied); + + return copied; +} + +static __poll_t counter_chrdev_poll(struct file *filp, + struct poll_table_struct *pollt) +{ + struct counter_device *const counter = filp->private_data; + __poll_t events = 0; + + if (!counter->ops) + return events; + + poll_wait(filp, &counter->events_wait, pollt); + + if (!kfifo_is_empty(&counter->events)) + events = EPOLLIN | EPOLLRDNORM; + + return events; +} + +static void counter_events_list_free(struct list_head *const events_list) +{ + struct counter_event_node *p, *n; + struct counter_comp_node *q, *o; + + list_for_each_entry_safe(p, n, events_list, l) { + /* Free associated component nodes */ + list_for_each_entry_safe(q, o, &p->comp_list, l) { + list_del(&q->l); + kfree(q); + } + + /* Free event node */ + list_del(&p->l); + kfree(p); + } +} + +static int counter_set_event_node(struct counter_device *const counter, + struct counter_watch *const watch, + const struct counter_comp_node *const cfg) +{ + struct counter_event_node *event_node; + int err = 0; + struct counter_comp_node *comp_node; + + /* Search for event in the list */ + list_for_each_entry(event_node, &counter->next_events_list, l) + if (event_node->event == watch->event && + event_node->channel == watch->channel) + break; + + /* If event is not already in the list */ + if (&event_node->l == &counter->next_events_list) { + /* Allocate new event node */ + event_node = kmalloc(sizeof(*event_node), GFP_KERNEL); + if (!event_node) + return -ENOMEM; + + /* Configure event node and add to the list */ + event_node->event = watch->event; + event_node->channel = watch->channel; + INIT_LIST_HEAD(&event_node->comp_list); + list_add(&event_node->l, &counter->next_events_list); + } + + /* Check if component watch has already been set before */ + list_for_each_entry(comp_node, &event_node->comp_list, l) + if (comp_node->parent == cfg->parent && + comp_node->comp.count_u8_read == cfg->comp.count_u8_read) { + err = -EINVAL; + goto exit_free_event_node; + } + + /* Allocate component node */ + comp_node = kmalloc(sizeof(*comp_node), GFP_KERNEL); + if (!comp_node) { + err = -ENOMEM; + goto exit_free_event_node; + } + *comp_node = *cfg; + + /* Add component node to event node */ + list_add_tail(&comp_node->l, &event_node->comp_list); + +exit_free_event_node: + /* Free event node if no one else is watching */ + if (list_empty(&event_node->comp_list)) { + list_del(&event_node->l); + kfree(event_node); + } + + return err; +} + +static int counter_enable_events(struct counter_device *const counter) +{ + unsigned long flags; + int err = 0; + + mutex_lock(&counter->n_events_list_lock); + spin_lock_irqsave(&counter->events_list_lock, flags); + + counter_events_list_free(&counter->events_list); + list_replace_init(&counter->next_events_list, + &counter->events_list); + + if (counter->ops->events_configure) + err = counter->ops->events_configure(counter); + + spin_unlock_irqrestore(&counter->events_list_lock, flags); + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static int counter_disable_events(struct counter_device *const counter) +{ + unsigned long flags; + int err = 0; + + spin_lock_irqsave(&counter->events_list_lock, flags); + + counter_events_list_free(&counter->events_list); + + if (counter->ops->events_configure) + err = counter->ops->events_configure(counter); + + spin_unlock_irqrestore(&counter->events_list_lock, flags); + + mutex_lock(&counter->n_events_list_lock); + + counter_events_list_free(&counter->next_events_list); + + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static int counter_add_watch(struct counter_device *const counter, + const unsigned long arg) +{ + void __user *const uwatch = (void __user *)arg; + struct counter_watch watch; + struct counter_comp_node comp_node = {}; + size_t parent, id; + struct counter_comp *ext; + size_t num_ext; + int err = 0; + + if (copy_from_user(&watch, uwatch, sizeof(watch))) + return -EFAULT; + + if (watch.component.type == COUNTER_COMPONENT_NONE) + goto no_component; + + parent = watch.component.parent; + + /* Configure parent component info for comp node */ + switch (watch.component.scope) { + case COUNTER_SCOPE_DEVICE: + ext = counter->ext; + num_ext = counter->num_ext; + break; + case COUNTER_SCOPE_SIGNAL: + if (parent >= counter->num_signals) + return -EINVAL; + parent = array_index_nospec(parent, counter->num_signals); + + comp_node.parent = counter->signals + parent; + + ext = counter->signals[parent].ext; + num_ext = counter->signals[parent].num_ext; + break; + case COUNTER_SCOPE_COUNT: + if (parent >= counter->num_counts) + return -EINVAL; + parent = array_index_nospec(parent, counter->num_counts); + + comp_node.parent = counter->counts + parent; + + ext = counter->counts[parent].ext; + num_ext = counter->counts[parent].num_ext; + break; + default: + return -EINVAL; + } + + id = watch.component.id; + + /* Configure component info for comp node */ + switch (watch.component.type) { + case COUNTER_COMPONENT_SIGNAL: + if (watch.component.scope != COUNTER_SCOPE_SIGNAL) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_SIGNAL_LEVEL; + comp_node.comp.signal_u32_read = counter->ops->signal_read; + break; + case COUNTER_COMPONENT_COUNT: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_U64; + comp_node.comp.count_u64_read = counter->ops->count_read; + break; + case COUNTER_COMPONENT_FUNCTION: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + + comp_node.comp.type = COUNTER_COMP_FUNCTION; + comp_node.comp.count_u32_read = counter->ops->function_read; + break; + case COUNTER_COMPONENT_SYNAPSE_ACTION: + if (watch.component.scope != COUNTER_SCOPE_COUNT) + return -EINVAL; + if (id >= counter->counts[parent].num_synapses) + return -EINVAL; + id = array_index_nospec(id, counter->counts[parent].num_synapses); + + comp_node.comp.type = COUNTER_COMP_SYNAPSE_ACTION; + comp_node.comp.action_read = counter->ops->action_read; + comp_node.comp.priv = counter->counts[parent].synapses + id; + break; + case COUNTER_COMPONENT_EXTENSION: + if (id >= num_ext) + return -EINVAL; + id = array_index_nospec(id, num_ext); + + comp_node.comp = ext[id]; + break; + default: + return -EINVAL; + } + /* Check if any read callback is set; this is part of a union */ + if (!comp_node.comp.count_u8_read) + return -EOPNOTSUPP; + +no_component: + mutex_lock(&counter->n_events_list_lock); + + if (counter->ops->watch_validate) { + err = counter->ops->watch_validate(counter, &watch); + if (err < 0) + goto err_exit; + } + + comp_node.component = watch.component; + + err = counter_set_event_node(counter, &watch, &comp_node); + +err_exit: + mutex_unlock(&counter->n_events_list_lock); + + return err; +} + +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct counter_device *const counter = filp->private_data; + int ret = -ENODEV; + + mutex_lock(&counter->ops_exist_lock); + + if (!counter->ops) + goto out_unlock; + + switch (cmd) { + case COUNTER_ADD_WATCH_IOCTL: + ret = counter_add_watch(counter, arg); + break; + case COUNTER_ENABLE_EVENTS_IOCTL: + ret = counter_enable_events(counter); + break; + case COUNTER_DISABLE_EVENTS_IOCTL: + ret = counter_disable_events(counter); + break; + default: + ret = -ENOIOCTLCMD; + break; + } + +out_unlock: + mutex_unlock(&counter->ops_exist_lock); + + return ret; +} + +static int counter_chrdev_open(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = container_of(inode->i_cdev, + typeof(*counter), + chrdev); + + if (test_and_set_bit_lock(0, counter->chrdev_lock)) + return -EBUSY; + + get_device(&counter->dev); + filp->private_data = counter; + + return nonseekable_open(inode, filp); +} + +static int counter_chrdev_release(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = filp->private_data; + int ret = 0; + + mutex_lock(&counter->ops_exist_lock); + + if (!counter->ops) { + counter_events_list_free(&counter->events_list); + counter_events_list_free(&counter->next_events_list); + ret = -ENODEV; + goto out_unlock; + } + + ret = counter_disable_events(counter); + if (ret < 0) { + mutex_unlock(&counter->ops_exist_lock); + return ret; + } + +out_unlock: + mutex_unlock(&counter->ops_exist_lock); + + put_device(&counter->dev); + clear_bit_unlock(0, counter->chrdev_lock); + + return ret; +} + +static const struct file_operations counter_fops = { + .owner = THIS_MODULE, + .llseek = no_llseek, + .read = counter_chrdev_read, + .poll = counter_chrdev_poll, + .unlocked_ioctl = counter_chrdev_ioctl, + .open = counter_chrdev_open, + .release = counter_chrdev_release, +}; + +int counter_chrdev_add(struct counter_device *const counter) +{ + /* Initialize Counter events lists */ + INIT_LIST_HEAD(&counter->events_list); + INIT_LIST_HEAD(&counter->next_events_list); + spin_lock_init(&counter->events_list_lock); + mutex_init(&counter->n_events_list_lock); + init_waitqueue_head(&counter->events_wait); + mutex_init(&counter->events_lock); + + /* Initialize character device */ + clear_bit(0, counter->chrdev_lock); + cdev_init(&counter->chrdev, &counter_fops); + + /* Allocate Counter events queue */ + return kfifo_alloc(&counter->events, 64, GFP_KERNEL); +} + +void counter_chrdev_remove(struct counter_device *const counter) +{ + kfifo_free(&counter->events); +} + +static int counter_get_data(struct counter_device *const counter, + const struct counter_comp_node *const comp_node, + u64 *const value) +{ + const struct counter_comp *const comp = &comp_node->comp; + void *const parent = comp_node->parent; + u8 value_u8 = 0; + u32 value_u32 = 0; + int ret; + + if (comp_node->component.type == COUNTER_COMPONENT_NONE) + return 0; + + switch (comp->type) { + case COUNTER_COMP_U8: + case COUNTER_COMP_BOOL: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + ret = comp->device_u8_read(counter, &value_u8); + break; + case COUNTER_SCOPE_SIGNAL: + ret = comp->signal_u8_read(counter, parent, &value_u8); + break; + case COUNTER_SCOPE_COUNT: + ret = comp->count_u8_read(counter, parent, &value_u8); + break; + } + *value = value_u8; + return ret; + case COUNTER_COMP_SIGNAL_LEVEL: + case COUNTER_COMP_FUNCTION: + case COUNTER_COMP_ENUM: + case COUNTER_COMP_COUNT_DIRECTION: + case COUNTER_COMP_COUNT_MODE: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + ret = comp->device_u32_read(counter, &value_u32); + break; + case COUNTER_SCOPE_SIGNAL: + ret = comp->signal_u32_read(counter, parent, + &value_u32); + break; + case COUNTER_SCOPE_COUNT: + ret = comp->count_u32_read(counter, parent, &value_u32); + break; + } + *value = value_u32; + return ret; + case COUNTER_COMP_U64: + switch (comp_node->component.scope) { + case COUNTER_SCOPE_DEVICE: + return comp->device_u64_read(counter, value); + case COUNTER_SCOPE_SIGNAL: + return comp->signal_u64_read(counter, parent, value); + case COUNTER_SCOPE_COUNT: + return comp->count_u64_read(counter, parent, value); + default: + return -EINVAL; + } + case COUNTER_COMP_SYNAPSE_ACTION: + ret = comp->action_read(counter, parent, comp->priv, + &value_u32); + *value = value_u32; + return ret; + default: + return -EINVAL; + } +} + +/** + * counter_push_event - queue event for userspace reading + * @counter: pointer to Counter structure + * @event: triggered event + * @channel: event channel + * + * Note: If no one is watching for the respective event, it is silently + * discarded. + */ +void counter_push_event(struct counter_device *const counter, const u8 event, + const u8 channel) +{ + struct counter_event ev; + unsigned int copied = 0; + unsigned long flags; + struct counter_event_node *event_node; + struct counter_comp_node *comp_node; + + ev.timestamp = ktime_get_ns(); + ev.watch.event = event; + ev.watch.channel = channel; + + /* Could be in an interrupt context, so use a spin lock */ + spin_lock_irqsave(&counter->events_list_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_node, &counter->events_list, l) + if (event_node->event == event && + event_node->channel == channel) + break; + + /* If event is not in the list */ + if (&event_node->l == &counter->events_list) + goto exit_early; + + /* Read and queue relevant comp for userspace */ + list_for_each_entry(comp_node, &event_node->comp_list, l) { + ev.watch.component = comp_node->component; + ev.status = -counter_get_data(counter, comp_node, &ev.value); + + copied += kfifo_in(&counter->events, &ev, 1); + } + +exit_early: + spin_unlock_irqrestore(&counter->events_list_lock, flags); + + if (copied) + wake_up_poll(&counter->events_wait, EPOLLIN); +} +EXPORT_SYMBOL_GPL(counter_push_event); diff --git a/drivers/counter/counter-chrdev.h b/drivers/counter/counter-chrdev.h new file mode 100644 index 000000000000..5529d16703c4 --- /dev/null +++ b/drivers/counter/counter-chrdev.h @@ -0,0 +1,14 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Counter character device interface + * Copyright (C) 2020 William Breathitt Gray + */ +#ifndef _COUNTER_CHRDEV_H_ +#define _COUNTER_CHRDEV_H_ + +#include + +int counter_chrdev_add(struct counter_device *const counter); +void counter_chrdev_remove(struct counter_device *const counter); + +#endif /* _COUNTER_CHRDEV_H_ */ diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c index 3cda2c47bacb..28dc1ff63c94 100644 --- a/drivers/counter/counter-core.c +++ b/drivers/counter/counter-core.c @@ -3,14 +3,22 @@ * Generic Counter interface * Copyright (C) 2020 William Breathitt Gray */ +#include #include #include +#include #include +#include #include #include #include +#include #include +#include +#include +#include +#include "counter-chrdev.h" #include "counter-sysfs.h" /* Provides a unique ID for each counter device */ @@ -18,6 +26,9 @@ static DEFINE_IDA(counter_ida); static void counter_device_release(struct device *dev) { + struct counter_device *const counter = dev_get_drvdata(dev); + + counter_chrdev_remove(counter); ida_free(&counter_ida, dev->id); } @@ -31,6 +42,8 @@ static struct bus_type counter_bus_type = { .dev_name = "counter", }; +static dev_t counter_devt; + /** * counter_register - register Counter to the system * @counter: pointer to Counter to register @@ -53,10 +66,13 @@ int counter_register(struct counter_device *const counter) if (id < 0) return id; + mutex_init(&counter->ops_exist_lock); + /* Configure device structure for Counter */ dev->id = id; dev->type = &counter_device_type; dev->bus = &counter_bus_type; + dev->devt = MKDEV(MAJOR(counter_devt), id); if (counter->parent) { dev->parent = counter->parent; dev->of_node = counter->parent->of_node; @@ -64,18 +80,22 @@ int counter_register(struct counter_device *const counter) device_initialize(dev); dev_set_drvdata(dev, counter); - /* Add Counter sysfs attributes */ - err = counter_sysfs_add(counter); + err = counter_chrdev_add(counter); if (err < 0) goto err_free_id; - /* Add device to system */ - err = device_add(dev); + err = counter_sysfs_add(counter); if (err < 0) - goto err_free_id; + goto err_remove_chrdev; + + err = cdev_device_add(&counter->chrdev, dev); + if (err < 0) + goto err_remove_chrdev; return 0; +err_remove_chrdev: + counter_chrdev_remove(counter); err_free_id: put_device(dev); return err; @@ -93,7 +113,16 @@ void counter_unregister(struct counter_device *const counter) if (!counter) return; - device_unregister(&counter->dev); + cdev_device_del(&counter->chrdev, &counter->dev); + + mutex_lock(&counter->ops_exist_lock); + + counter->ops = NULL; + wake_up(&counter->events_wait); + + mutex_unlock(&counter->ops_exist_lock); + + put_device(&counter->dev); } EXPORT_SYMBOL_GPL(counter_unregister); @@ -127,13 +156,30 @@ int devm_counter_register(struct device *dev, } EXPORT_SYMBOL_GPL(devm_counter_register); +#define COUNTER_DEV_MAX 256 + static int __init counter_init(void) { - return bus_register(&counter_bus_type); + int err; + + err = bus_register(&counter_bus_type); + if (err < 0) + return err; + + err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX, "counter"); + if (err < 0) + goto err_unregister_bus; + + return 0; + +err_unregister_bus: + bus_unregister(&counter_bus_type); + return err; } static void __exit counter_exit(void) { + unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX); bus_unregister(&counter_bus_type); } diff --git a/include/linux/counter.h b/include/linux/counter.h index 7c9f7e23953a..9c9984655f8c 100644 --- a/include/linux/counter.h +++ b/include/linux/counter.h @@ -6,9 +6,14 @@ #ifndef _COUNTER_H_ #define _COUNTER_H_ +#include #include #include +#include +#include +#include #include +#include #include struct counter_device; @@ -199,6 +204,20 @@ struct counter_count { size_t num_ext; }; +/** + * struct counter_event_node - Counter Event node + * @l: list of current watching Counter events + * @event: event that triggers + * @channel: event channel + * @comp_list: list of components to watch when event triggers + */ +struct counter_event_node { + struct list_head l; + u8 event; + u8 channel; + struct list_head comp_list; +}; + /** * struct counter_ops - Callbacks from driver * @signal_read: optional read callback for Signals. The read level of @@ -222,6 +241,13 @@ struct counter_count { * @action_write: optional write callback for Synapse action modes. The * action mode to write for the respective Synapse is * passed in via the action parameter. + * @events_configure: optional write callback to configure events. The list of + * struct counter_event_node may be accessed via the + * events_list member of the counter parameter. + * @watch_validate: optional callback to validate a watch. The Counter + * component watch configuration is passed in via the watch + * parameter. A return value of 0 indicates a valid Counter + * component watch configuration. */ struct counter_ops { int (*signal_read)(struct counter_device *counter, @@ -245,6 +271,9 @@ struct counter_ops { struct counter_count *count, struct counter_synapse *synapse, enum counter_synapse_action action); + int (*events_configure)(struct counter_device *counter); + int (*watch_validate)(struct counter_device *counter, + const struct counter_watch *watch); }; /** @@ -260,6 +289,16 @@ struct counter_ops { * @num_ext: number of Counter device extensions specified in @ext * @priv: optional private data supplied by driver * @dev: internal device structure + * @chrdev: internal character device structure + * @events_list: list of current watching Counter events + * @events_list_lock: lock to protect Counter events list operations + * @next_events_list: list of next watching Counter events + * @n_events_list_lock: lock to protect Counter next events list operations + * @events: queue of detected Counter events + * @events_wait: wait queue to allow blocking reads of Counter events + * @events_lock: lock to protect Counter events queue read operations + * @chrdev_lock: lock to limit chrdev to a single open at a time + * @ops_exist_lock: lock to prevent use during removal */ struct counter_device { const char *name; @@ -278,12 +317,24 @@ struct counter_device { void *priv; struct device dev; + struct cdev chrdev; + struct list_head events_list; + spinlock_t events_list_lock; + struct list_head next_events_list; + struct mutex n_events_list_lock; + DECLARE_KFIFO_PTR(events, struct counter_event); + wait_queue_head_t events_wait; + struct mutex events_lock; + DECLARE_BITMAP(chrdev_lock, 1); + struct mutex ops_exist_lock; }; int counter_register(struct counter_device *const counter); void counter_unregister(struct counter_device *const counter); int devm_counter_register(struct device *dev, struct counter_device *const counter); +void counter_push_event(struct counter_device *const counter, const u8 event, + const u8 channel); #define COUNTER_COMP_DEVICE_U8(_name, _read, _write) \ { \ diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h index 6113938a6044..d0aa95aeff7b 100644 --- a/include/uapi/linux/counter.h +++ b/include/uapi/linux/counter.h @@ -6,6 +6,19 @@ #ifndef _UAPI_COUNTER_H_ #define _UAPI_COUNTER_H_ +#include +#include + +/* Component type definitions */ +enum counter_component_type { + COUNTER_COMPONENT_NONE, + COUNTER_COMPONENT_SIGNAL, + COUNTER_COMPONENT_COUNT, + COUNTER_COMPONENT_FUNCTION, + COUNTER_COMPONENT_SYNAPSE_ACTION, + COUNTER_COMPONENT_EXTENSION, +}; + /* Component scope definitions */ enum counter_scope { COUNTER_SCOPE_DEVICE, @@ -13,6 +26,91 @@ enum counter_scope { COUNTER_SCOPE_COUNT, }; +/** + * struct counter_component - Counter component identification + * @type: component type (one of enum counter_component_type) + * @scope: component scope (one of enum counter_scope) + * @parent: parent ID (matching the ID suffix of the respective parent sysfs + * path as described by the ABI documentation file + * Documentation/ABI/testing/sysfs-bus-counter) + * @id: component ID (matching the ID provided by the respective *_component_id + * sysfs attribute of the desired component) + * + * For example, if the Count 2 ceiling extension of Counter device 4 is desired, + * set type equal to COUNTER_COMPONENT_EXTENSION, scope equal to + * COUNTER_COUNT_SCOPE, parent equal to 2, and id equal to the value provided by + * the respective /sys/bus/counter/devices/counter4/count2/ceiling_component_id + * sysfs attribute. + */ +struct counter_component { + __u8 type; + __u8 scope; + __u8 parent; + __u8 id; +}; + +/* Event type definitions */ +enum counter_event_type { + /* Count value increased past ceiling */ + COUNTER_EVENT_OVERFLOW, + /* Count value decreased past floor */ + COUNTER_EVENT_UNDERFLOW, + /* Count value increased past ceiling, or decreased past floor */ + COUNTER_EVENT_OVERFLOW_UNDERFLOW, + /* Count value reached threshold */ + COUNTER_EVENT_THRESHOLD, + /* Index signal detected */ + COUNTER_EVENT_INDEX, +}; + +/** + * struct counter_watch - Counter component watch configuration + * @component: component to watch when event triggers + * @event: event that triggers (one of enum counter_event_type) + * @channel: event channel (typically 0 unless the device supports concurrent + * events of the same type) + */ +struct counter_watch { + struct counter_component component; + __u8 event; + __u8 channel; +}; + +/* + * Queues a Counter watch for the specified event. + * + * The queued watches will not be applied until COUNTER_ENABLE_EVENTS_IOCTL is + * called. + */ +#define COUNTER_ADD_WATCH_IOCTL _IOW(0x3E, 0x00, struct counter_watch) +/* + * Enables monitoring the events specified by the Counter watches that were + * queued by COUNTER_ADD_WATCH_IOCTL. + * + * If events are already enabled, the new set of watches replaces the old one. + * Calling this ioctl also has the effect of clearing the queue of watches added + * by COUNTER_ADD_WATCH_IOCTL. + */ +#define COUNTER_ENABLE_EVENTS_IOCTL _IO(0x3E, 0x01) +/* + * Stops monitoring the previously enabled events. + */ +#define COUNTER_DISABLE_EVENTS_IOCTL _IO(0x3E, 0x02) + +/** + * struct counter_event - Counter event data + * @timestamp: best estimate of time of event occurrence, in nanoseconds + * @value: component value + * @watch: component watch configuration + * @status: return status (system error number) + */ +struct counter_event { + __aligned_u64 timestamp; + __aligned_u64 value; + struct counter_watch watch; + __u8 status; +}; + /* Count direction values */ enum counter_count_direction { COUNTER_COUNT_DIRECTION_FORWARD, -- 2.32.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel