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[72.189.64.225]) by smtp.gmail.com with ESMTPSA id j72sm3331351qke.20.2020.07.21.12.36.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jul 2020 12:36:12 -0700 (PDT) From: William Breathitt Gray To: jic23@kernel.org Cc: 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-stm32@st-md-mailman.stormreply.com, 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, William Breathitt Gray Subject: [PATCH v4 3/5] counter: Add character device interface Date: Tue, 21 Jul 2020 15:35:49 -0400 Message-Id: <08b3ac7349a59ba7fa5cd438bbe78360842ccd11.1595358237.git.vilhelm.gray@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org 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. A high-level view of how a count value is passed down from a counter driver is exemplified by the following: ---------------------- / Counter device \ +----------------------+ | Count register: 0x28 | +----------------------+ | ----------------- / raw count data / ----------------- | V +----------------------------+ | Counter device driver |----------+ +----------------------------+ | | Processes data from device | ------------------- |----------------------------| / driver callbacks / | Type: u64 | ------------------- | Value: 42 | | +----------------------------+ | | | ---------- | / u64 / | ---------- | | | | V | +----------------------+ | | Counter core | | +----------------------+ | | Routes device driver | | | callbacks to the | | | userspace interfaces | | +----------------------+ | | | ------------------- | / driver callbacks / | ------------------- | | +-------+---------------+ | | | | | +-------|-------+ | | | V | V +--------------------+ | +---------------------+ | Counter sysfs |<-+->| Counter chrdev | +--------------------+ +---------------------+ | Translates to the | | Translates to the | | standard Counter | | standard Counter | | sysfs output | | character device | |--------------------| |---------------------+ | Type: const char * | | Type: u64 | | Value: "42" | | Value: 42 | +--------------------+ +---------------------+ | | --------------- ----------------------- / const char * / / struct counter_event / --------------- ----------------------- | | | V | +-----------+ | | read | | +-----------+ | \ Count: 42 / | ----------- | V +--------------------------------------------------+ | `/sys/bus/counter/devices/counterX/countY/count` | +--------------------------------------------------+ \ Count: "42" / -------------------------------------------------- Counter character device nodes are created under the `/dev` directory as `counterX`, where `X` is the respective counter device id. Defines for the standard Counter data types are exposed via the userspace `include/uapi/linux/counter.h` file. Counter events -------------- Counter device drivers can support Counter events by utilizing the `counter_push_event` function: int counter_push_event(struct counter_device *const counter, const u8 event); The event id is specified by the `event` parameter. When this function is called, the Counter data associated with the respective event is gathered, and a `struct counter_event` is generated for each datum and pushed to userspace. Counter events can be configured by users to report various Counter data of interest. This can be conceptualized as a list of Counter component read calls to perform. For example: +------------------------+------------------------+ | Event 0 | Event 1 | +------------------------+------------------------+ | * Count 0 | * Signal 0 | | * Count 1 | * Signal 0 Extension 0 | | * Signal 3 | * Extension 4 | | * Count 4 Extension 2 | | | * Signal 5 Extension 0 | | +------------------------+------------------------+ When `counter_push_event(counter, 1)` is called for example, it will go down the list for Event 1 and execute the read callbacks for Signal 0, Signal 0 Extension 0, and Extension 4 -- the data returned for each is pushed to a kfifo as a `struct counter_event`, which userspace can retrieve via a standard read operation on the respective character device node. Userspace --------- Userspace applications can configure Counter events via ioctl operations on the Counter character device node. There following ioctl codes are supported and provided by the `linux/counter.h` userspace header file: * COUNTER_CLEAR_WATCHES_IOCTL: Clear all Counter watches from all events * COUNTER_SET_WATCH_IOCTL: Set a Counter watch on the specified event To configure events to gather Counter data, users first populate a `struct counter_watch` with the relevant event id and the information for the desired Counter component from which to read, and then pass it via the `COUNTER_SET_WATCH_IOCTL` ioctl command. Userspace applications can then execute a `read` operation (optionally calling `poll` first) on the Counter character device node to retrieve `struct counter_event` elements with the desired data. For example, the following userspace code opens `/dev/counter0`, configures Event 0 to gather Count 0 and Count 1, and prints out the data as it becomes available on the character device node: #include #include #include #include #include #include struct counter_watch watches[2] = { { .event = 0, .component.owner_type = COUNTER_OWNER_TYPE_COUNT, .component.owner_id = 0, .component.type = COUNTER_COMPONENT_TYPE_COUNT, }, { .event = 0, .component.owner_type = COUNTER_OWNER_TYPE_COUNT, .component.owner_id = 1, .component.type = COUNTER_COMPONENT_TYPE_COUNT, }, }; int main(void) { struct pollfd pfd = { .events = POLLIN }; struct counter_event event_data[2]; pfd.fd = open("/dev/counter0", O_RDWR); ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches); ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches + 1); for (;;) { poll(&pfd, 1, -1); read(pfd.fd, event_data, sizeof(event_data)); printf("Timestamp 0: %llu\nCount 0: %llu\n" "Timestamp 1: %llu\nCount 1: %llu\n", (unsigned long long)event_data[0].timestamp, (unsigned long long)event_data[0].value_u64, (unsigned long long)event_data[1].timestamp, (unsigned long long)event_data[1].value_u64); } return 0; } Cc: David Lechner Cc: Gwendal Grignou Signed-off-by: William Breathitt Gray --- drivers/counter/Makefile | 2 +- drivers/counter/counter-chrdev.c | 441 +++++++++++++++++++++++++++++++ drivers/counter/counter-chrdev.h | 16 ++ drivers/counter/counter-core.c | 35 ++- include/linux/counter.h | 15 ++ include/uapi/linux/counter.h | 52 ++++ 6 files changed, 558 insertions(+), 3 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 cbe1d06af6a9..c4870eb5b1dd 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_STM32_TIMER_CNT) += stm32-timer-cnt.o diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c new file mode 100644 index 000000000000..9aa2d32e7bc9 --- /dev/null +++ b/drivers/counter/counter-chrdev.c @@ -0,0 +1,441 @@ +// 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 "counter-chrdev.h" + +struct counter_data_item { + struct list_head l; + struct counter_component component; + struct counter_data data; + void *owner; +}; + +struct counter_event_item { + struct list_head l; + u8 event; + struct list_head data_list; +}; + +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 long flags; + unsigned int copied; + + 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)); + if (err) + return err; + } + + raw_spin_lock_irqsave(&counter->events_lock, flags); + err = kfifo_to_user(&counter->events, buf, len, &copied); + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + if (err) + 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; + + 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 counter_device *const counter) +{ + unsigned long flags; + struct counter_event_item *p, *n; + struct counter_data_item *q, *o; + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + list_for_each_entry_safe(p, n, &counter->events_list, l) { + /* Free associated data items */ + list_for_each_entry_safe(q, o, &p->data_list, l) { + list_del(&q->l); + kfree(q); + } + + /* Free event item */ + list_del(&p->l); + kfree(p); + } + + raw_spin_unlock_irqrestore(&counter->events_lock, flags); +} + +static int counter_set_event_item(struct counter_device *const counter, + const u8 event, + const struct counter_data_item *const cfg) +{ + unsigned long flags; + struct counter_event_item *event_item; + int err; + struct counter_data_item *data_item; + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_item, &counter->events_list, l) + if (event_item->event == event) + break; + + /* If event is not already in the list */ + if (&event_item->l == &counter->events_list) { + /* Allocate new event item */ + event_item = kmalloc(sizeof(*event_item), GFP_ATOMIC); + if (!event_item) { + err = -ENOMEM; + goto err_event_item; + } + + /* Configure event item and add to the list */ + event_item->event = event; + INIT_LIST_HEAD(&event_item->data_list); + list_add(&event_item->l, &counter->events_list); + } + + /* Search for data item in the list */ + list_for_each_entry(data_item, &event_item->data_list, l) + if (data_item->owner == cfg->owner && + data_item->data.count_u8_read == cfg->data.count_u8_read) { + err = -EINVAL; + goto err_data_item; + } + + /* Allocate data item */ + data_item = kmalloc(sizeof(*data_item), GFP_ATOMIC); + if (!data_item) { + err = -ENOMEM; + goto err_data_item; + } + *data_item = *cfg; + + /* Add data item to event item */ + list_add_tail(&data_item->l, &event_item->data_list); + + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + + return 0; + +err_data_item: + if (list_empty(&event_item->data_list)) { + list_del(&event_item->l); + kfree(event_item); + } +err_event_item: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + return err; +} + +static int counter_set_watch(struct counter_device *const counter, + const unsigned long arg) +{ + void __user *const uwatch = (void __user *)arg; + struct counter_watch watch; + struct counter_data_item data_item; + size_t owner_id, id; + struct counter_data *ext; + size_t num_ext; + + if (copy_from_user(&watch, uwatch, sizeof(watch))) + return -EFAULT; + owner_id = watch.component.owner_id; + id = watch.component.id; + + /* Configure owner info for data item */ + switch (watch.component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + data_item.owner = NULL; + + ext = counter->ext; + num_ext = counter->num_ext; + break; + case COUNTER_OWNER_TYPE_SIGNAL: + if (counter->num_signals < owner_id + 1) + return -EINVAL; + + data_item.owner = counter->signals + owner_id; + + ext = counter->signals[owner_id].ext; + num_ext = counter->signals[owner_id].num_ext; + break; + case COUNTER_OWNER_TYPE_COUNT: + if (counter->num_counts < owner_id + 1) + return -EINVAL; + + data_item.owner = counter->counts + owner_id; + + ext = counter->counts[owner_id].ext; + num_ext = counter->counts[owner_id].num_ext; + break; + default: + return -EINVAL; + } + + /* Configure component info for data item */ + switch (watch.component.type) { + case COUNTER_COMPONENT_TYPE_SIGNAL: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_SIGNAL) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_SIGNAL; + data_item.data.signal_u8_read = counter->signal_read; + break; + case COUNTER_COMPONENT_TYPE_COUNT: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_U64; + data_item.data.count_u64_read = counter->count_read; + break; + case COUNTER_COMPONENT_TYPE_COUNT_FUNCTION: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_COUNT_FUNCTION; + data_item.data.count_u8_read = counter->function_read; + break; + case COUNTER_COMPONENT_TYPE_SYNAPSE_ACTION: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + if (counter->counts[owner_id].num_synapses < id + 1) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_SYNAPSE_ACTION; + data_item.data.action_read = counter->action_read; + data_item.data.priv = counter->counts[owner_id].synapses + id; + break; + case COUNTER_COMPONENT_TYPE_EXTENSION: + if (num_ext < id + 1) + return -EINVAL; + + data_item.data = ext[id]; + break; + default: + return -EINVAL; + } + if (!data_item.data.count_u8_read) + return -EFAULT; + data_item.component = watch.component; + + return counter_set_event_item(counter, watch.event, &data_item); +} + +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct counter_device *const counter = filp->private_data; + + switch (cmd) { + case COUNTER_CLEAR_WATCHES_IOCTL: + counter_events_list_free(counter); + break; + case COUNTER_SET_WATCH_IOCTL: + return counter_set_watch(counter, arg); + default: + return -ENOIOCTLCMD; + } + + return 0; +} + +static int counter_chrdev_open(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = container_of(inode->i_cdev, + typeof(*counter), + chrdev); + + 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; + + put_device(&counter->dev); + + counter_events_list_free(counter); + + return 0; +} + +static const struct file_operations counter_fops = { + .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, + const dev_t counter_devt) +{ + struct device *const dev = &counter->dev; + struct cdev *const chrdev = &counter->chrdev; + + /* Initialize Counter events list */ + INIT_LIST_HEAD(&counter->events_list); + raw_spin_lock_init(&counter->events_lock); + + /* Initialize Counter events queue */ + INIT_KFIFO(counter->events); + init_waitqueue_head(&counter->events_wait); + + /* Initialize character device */ + cdev_init(chrdev, &counter_fops); + dev->devt = MKDEV(MAJOR(counter_devt), counter->id); + cdev_set_parent(chrdev, &dev->kobj); + + return cdev_add(chrdev, dev->devt, 1); +} + +void counter_chrdev_free(struct counter_device *const counter) +{ + cdev_del(&counter->chrdev); +} + +static int counter_get_data(struct counter_device *const counter, + const struct counter_data_item *const data_item, + void *const value) +{ + const struct counter_data *const data = &data_item->data; + void *const owner = data_item->owner; + + switch (data->type) { + case COUNTER_DATA_TYPE_U8: + case COUNTER_DATA_TYPE_BOOL: + case COUNTER_DATA_TYPE_SIGNAL: + case COUNTER_DATA_TYPE_COUNT_FUNCTION: + case COUNTER_DATA_TYPE_ENUM: + case COUNTER_DATA_TYPE_COUNT_DIRECTION: + case COUNTER_DATA_TYPE_COUNT_MODE: + switch (data_item->component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + return data->device_u8_read(counter, value); + case COUNTER_OWNER_TYPE_SIGNAL: + return data->signal_u8_read(counter, owner, value); + case COUNTER_OWNER_TYPE_COUNT: + return data->count_u8_read(counter, owner, value); + } + break; + case COUNTER_DATA_TYPE_U64: + switch (data_item->component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + return data->device_u64_read(counter, value); + case COUNTER_OWNER_TYPE_SIGNAL: + return data->signal_u64_read(counter, owner, value); + case COUNTER_OWNER_TYPE_COUNT: + return data->count_u64_read(counter, owner, value); + } + break; + case COUNTER_DATA_TYPE_SYNAPSE_ACTION: + return data->action_read(counter, owner, data->priv, value); + } + + return 0; +} + +/** + * counter_push_event - queue event for userspace reading + * @counter: pointer to Counter structure + * @event: triggered event + * + * Note: If no one is watching for the respective event, it is silently + * discarded. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int counter_push_event(struct counter_device *const counter, const u8 event) +{ + struct counter_event ev = { .watch.event = event }; + unsigned int copied = 0; + unsigned long flags; + struct counter_event_item *event_item; + struct counter_data_item *data_item; + int err; + + ev.timestamp = ktime_get_ns(); + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_item, &counter->events_list, l) + if (event_item->event == event) + break; + + /* If event is not in the list */ + if (&event_item->l == &counter->events_list) + goto exit_early; + + /* Read and queue relevant data for userspace */ + list_for_each_entry(data_item, &event_item->data_list, l) { + err = counter_get_data(counter, data_item, &ev.value_u8); + if (err) + goto err_counter_get_data; + + ev.watch.component = data_item->component; + + copied += kfifo_put(&counter->events, ev); + } + + if (copied) + wake_up_poll(&counter->events_wait, EPOLLIN); + +exit_early: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + + return 0; + +err_counter_get_data: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + return err; +} +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..7ab0797d3857 --- /dev/null +++ b/drivers/counter/counter-chrdev.h @@ -0,0 +1,16 @@ +/* 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 +#include + +int counter_chrdev_add(struct counter_device *const counter, + const dev_t counter_devt); +void counter_chrdev_free(struct counter_device *const counter); + +#endif /* _COUNTER_CHRDEV_H_ */ diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c index 499664809c75..d9ae889a0a8c 100644 --- a/drivers/counter/counter-core.c +++ b/drivers/counter/counter-core.c @@ -5,12 +5,16 @@ */ #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 */ @@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = { .name = "counter" }; +static dev_t counter_devt; + /** * counter_register - register Counter to the system * @counter: pointer to Counter to register @@ -62,10 +68,15 @@ int counter_register(struct counter_device *const counter) device_initialize(dev); dev_set_drvdata(dev, counter); + /* Add Counter character device */ + err = counter_chrdev_add(counter, counter_devt); + if (err) + goto err_free_id; + /* Add Counter sysfs attributes */ err = counter_sysfs_add(counter); if (err) - goto err_free_id; + goto err_free_chrdev; /* Add device to system */ err = device_add(dev); @@ -76,6 +87,8 @@ int counter_register(struct counter_device *const counter) err_free_sysfs: counter_sysfs_free(counter); +err_free_chrdev: + counter_chrdev_free(counter); err_free_id: ida_simple_remove(&counter_ida, counter->id); return err; @@ -93,6 +106,7 @@ void counter_unregister(struct counter_device *const counter) if (counter) { device_del(&counter->dev); counter_sysfs_free(counter); + counter_chrdev_free(counter); } } EXPORT_SYMBOL_GPL(counter_unregister); @@ -139,13 +153,30 @@ 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 76657d203a26..d4f2f2463ea3 100644 --- a/include/linux/counter.h +++ b/include/linux/counter.h @@ -6,10 +6,14 @@ #ifndef _COUNTER_H_ #define _COUNTER_H_ +#include #include #include +#include #include +#include #include +#include #include struct counter_device; @@ -166,6 +170,11 @@ struct counter_attribute_group { * @priv: optional private data supplied by driver * @id: unique ID used to identify the Counter * @dev: internal device structure + * @chrdev: internal character device structure + * @events_list: list for Counter events + * @events_lock: synchronization lock for Counter events + * @events_wait: wait queue to allow blocking reads of Counter events + * @events: queue of detected Counter events * @dynamic_names_list: list for dynamically allocated names * @groups_list: attribute groups list (for Signals, Counts, and ext) * @num_groups: number of attribute groups containers @@ -204,6 +213,11 @@ struct counter_device { int id; struct device dev; + struct cdev chrdev; + struct list_head events_list; + raw_spinlock_t events_lock; + wait_queue_head_t events_wait; + DECLARE_KFIFO(events, struct counter_event, 64); struct list_head dynamic_names_list; struct counter_attribute_group *groups_list; size_t num_groups; @@ -216,6 +230,7 @@ int devm_counter_register(struct device *dev, struct counter_device *const counter); void devm_counter_unregister(struct device *dev, struct counter_device *const counter); +int counter_push_event(struct counter_device *const counter, const u8 event); #define COUNTER_DATA_DEVICE_U8(_name, _read, _write) \ { \ diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h index 2ddee9fc93e0..b903d2ad9a94 100644 --- a/include/uapi/linux/counter.h +++ b/include/uapi/linux/counter.h @@ -6,10 +6,62 @@ #ifndef _UAPI_COUNTER_H_ #define _UAPI_COUNTER_H_ +#include +#include + #define COUNTER_OWNER_TYPE_DEVICE 0 #define COUNTER_OWNER_TYPE_SIGNAL 1 #define COUNTER_OWNER_TYPE_COUNT 2 +#define COUNTER_COMPONENT_TYPE_SIGNAL 0 +#define COUNTER_COMPONENT_TYPE_COUNT 1 +#define COUNTER_COMPONENT_TYPE_COUNT_FUNCTION 2 +#define COUNTER_COMPONENT_TYPE_SYNAPSE_ACTION 3 +#define COUNTER_COMPONENT_TYPE_EXTENSION 4 + +/** + * struct counter_component - Counter component identification + * @owner_type: owner type (Device, Count, or Signal) + * @owner_id: owner identification number + * @type: component type (Count, extension, etc.) + * @id: component identification number + */ +struct counter_component { + __u8 owner_type; + __u64 owner_id; + __u8 type; + __u64 id; +}; + +/** + * struct counter_watch - Counter component watch configuration + * @event: event that triggers + * @component: component to watch when event triggers + */ +struct counter_watch { + __u8 event; + struct counter_component component; +}; + +#define COUNTER_CLEAR_WATCHES_IOCTL _IO(0x3E, 0x00) +#define COUNTER_SET_WATCH_IOCTL _IOW(0x3E, 0x01, struct counter_watch) + +/** + * struct counter_event - Counter event data + * @timestamp: best estimate of time of event occurrence, in nanoseconds + * @watch: component watch configuration + * @value_u8: component value as __u8 data type + * @value_u64: component value as __u64 data type + */ +struct counter_event { + __u64 timestamp; + struct counter_watch watch; + union { + __u8 value_u8; + __u64 value_u64; + }; +}; + #define COUNTER_COUNT_DIRECTION_FORWARD 0 #define COUNTER_COUNT_DIRECTION_BACKWARD 1 -- 2.27.0 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=-13.0 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_SIGNED,DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 5671CC433E8 for ; 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[72.189.64.225]) by smtp.gmail.com with ESMTPSA id j72sm3331351qke.20.2020.07.21.12.36.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 21 Jul 2020 12:36:12 -0700 (PDT) From: William Breathitt Gray To: jic23@kernel.org Subject: [PATCH v4 3/5] counter: Add character device interface Date: Tue, 21 Jul 2020 15:35:49 -0400 Message-Id: <08b3ac7349a59ba7fa5cd438bbe78360842ccd11.1595358237.git.vilhelm.gray@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: References: MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200721_153615_590444_A27450CA X-CRM114-Status: GOOD ( 31.70 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kamel.bouhara@bootlin.com, gwendal@chromium.org, david@lechnology.com, linux-iio@vger.kernel.org, patrick.havelange@essensium.com, alexandre.belloni@bootlin.com, linux-kernel@vger.kernel.org, mcoquelin.stm32@gmail.com, William Breathitt Gray , fabrice.gasnier@st.com, syednwaris@gmail.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, alexandre.torgue@st.com 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. A high-level view of how a count value is passed down from a counter driver is exemplified by the following: ---------------------- / Counter device \ +----------------------+ | Count register: 0x28 | +----------------------+ | ----------------- / raw count data / ----------------- | V +----------------------------+ | Counter device driver |----------+ +----------------------------+ | | Processes data from device | ------------------- |----------------------------| / driver callbacks / | Type: u64 | ------------------- | Value: 42 | | +----------------------------+ | | | ---------- | / u64 / | ---------- | | | | V | +----------------------+ | | Counter core | | +----------------------+ | | Routes device driver | | | callbacks to the | | | userspace interfaces | | +----------------------+ | | | ------------------- | / driver callbacks / | ------------------- | | +-------+---------------+ | | | | | +-------|-------+ | | | V | V +--------------------+ | +---------------------+ | Counter sysfs |<-+->| Counter chrdev | +--------------------+ +---------------------+ | Translates to the | | Translates to the | | standard Counter | | standard Counter | | sysfs output | | character device | |--------------------| |---------------------+ | Type: const char * | | Type: u64 | | Value: "42" | | Value: 42 | +--------------------+ +---------------------+ | | --------------- ----------------------- / const char * / / struct counter_event / --------------- ----------------------- | | | V | +-----------+ | | read | | +-----------+ | \ Count: 42 / | ----------- | V +--------------------------------------------------+ | `/sys/bus/counter/devices/counterX/countY/count` | +--------------------------------------------------+ \ Count: "42" / -------------------------------------------------- Counter character device nodes are created under the `/dev` directory as `counterX`, where `X` is the respective counter device id. Defines for the standard Counter data types are exposed via the userspace `include/uapi/linux/counter.h` file. Counter events -------------- Counter device drivers can support Counter events by utilizing the `counter_push_event` function: int counter_push_event(struct counter_device *const counter, const u8 event); The event id is specified by the `event` parameter. When this function is called, the Counter data associated with the respective event is gathered, and a `struct counter_event` is generated for each datum and pushed to userspace. Counter events can be configured by users to report various Counter data of interest. This can be conceptualized as a list of Counter component read calls to perform. For example: +------------------------+------------------------+ | Event 0 | Event 1 | +------------------------+------------------------+ | * Count 0 | * Signal 0 | | * Count 1 | * Signal 0 Extension 0 | | * Signal 3 | * Extension 4 | | * Count 4 Extension 2 | | | * Signal 5 Extension 0 | | +------------------------+------------------------+ When `counter_push_event(counter, 1)` is called for example, it will go down the list for Event 1 and execute the read callbacks for Signal 0, Signal 0 Extension 0, and Extension 4 -- the data returned for each is pushed to a kfifo as a `struct counter_event`, which userspace can retrieve via a standard read operation on the respective character device node. Userspace --------- Userspace applications can configure Counter events via ioctl operations on the Counter character device node. There following ioctl codes are supported and provided by the `linux/counter.h` userspace header file: * COUNTER_CLEAR_WATCHES_IOCTL: Clear all Counter watches from all events * COUNTER_SET_WATCH_IOCTL: Set a Counter watch on the specified event To configure events to gather Counter data, users first populate a `struct counter_watch` with the relevant event id and the information for the desired Counter component from which to read, and then pass it via the `COUNTER_SET_WATCH_IOCTL` ioctl command. Userspace applications can then execute a `read` operation (optionally calling `poll` first) on the Counter character device node to retrieve `struct counter_event` elements with the desired data. For example, the following userspace code opens `/dev/counter0`, configures Event 0 to gather Count 0 and Count 1, and prints out the data as it becomes available on the character device node: #include #include #include #include #include #include struct counter_watch watches[2] = { { .event = 0, .component.owner_type = COUNTER_OWNER_TYPE_COUNT, .component.owner_id = 0, .component.type = COUNTER_COMPONENT_TYPE_COUNT, }, { .event = 0, .component.owner_type = COUNTER_OWNER_TYPE_COUNT, .component.owner_id = 1, .component.type = COUNTER_COMPONENT_TYPE_COUNT, }, }; int main(void) { struct pollfd pfd = { .events = POLLIN }; struct counter_event event_data[2]; pfd.fd = open("/dev/counter0", O_RDWR); ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches); ioctl(pfd.fd, COUNTER_SET_WATCH_IOCTL, watches + 1); for (;;) { poll(&pfd, 1, -1); read(pfd.fd, event_data, sizeof(event_data)); printf("Timestamp 0: %llu\nCount 0: %llu\n" "Timestamp 1: %llu\nCount 1: %llu\n", (unsigned long long)event_data[0].timestamp, (unsigned long long)event_data[0].value_u64, (unsigned long long)event_data[1].timestamp, (unsigned long long)event_data[1].value_u64); } return 0; } Cc: David Lechner Cc: Gwendal Grignou Signed-off-by: William Breathitt Gray --- drivers/counter/Makefile | 2 +- drivers/counter/counter-chrdev.c | 441 +++++++++++++++++++++++++++++++ drivers/counter/counter-chrdev.h | 16 ++ drivers/counter/counter-core.c | 35 ++- include/linux/counter.h | 15 ++ include/uapi/linux/counter.h | 52 ++++ 6 files changed, 558 insertions(+), 3 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 cbe1d06af6a9..c4870eb5b1dd 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_STM32_TIMER_CNT) += stm32-timer-cnt.o diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c new file mode 100644 index 000000000000..9aa2d32e7bc9 --- /dev/null +++ b/drivers/counter/counter-chrdev.c @@ -0,0 +1,441 @@ +// 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 "counter-chrdev.h" + +struct counter_data_item { + struct list_head l; + struct counter_component component; + struct counter_data data; + void *owner; +}; + +struct counter_event_item { + struct list_head l; + u8 event; + struct list_head data_list; +}; + +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 long flags; + unsigned int copied; + + 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)); + if (err) + return err; + } + + raw_spin_lock_irqsave(&counter->events_lock, flags); + err = kfifo_to_user(&counter->events, buf, len, &copied); + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + if (err) + 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; + + 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 counter_device *const counter) +{ + unsigned long flags; + struct counter_event_item *p, *n; + struct counter_data_item *q, *o; + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + list_for_each_entry_safe(p, n, &counter->events_list, l) { + /* Free associated data items */ + list_for_each_entry_safe(q, o, &p->data_list, l) { + list_del(&q->l); + kfree(q); + } + + /* Free event item */ + list_del(&p->l); + kfree(p); + } + + raw_spin_unlock_irqrestore(&counter->events_lock, flags); +} + +static int counter_set_event_item(struct counter_device *const counter, + const u8 event, + const struct counter_data_item *const cfg) +{ + unsigned long flags; + struct counter_event_item *event_item; + int err; + struct counter_data_item *data_item; + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_item, &counter->events_list, l) + if (event_item->event == event) + break; + + /* If event is not already in the list */ + if (&event_item->l == &counter->events_list) { + /* Allocate new event item */ + event_item = kmalloc(sizeof(*event_item), GFP_ATOMIC); + if (!event_item) { + err = -ENOMEM; + goto err_event_item; + } + + /* Configure event item and add to the list */ + event_item->event = event; + INIT_LIST_HEAD(&event_item->data_list); + list_add(&event_item->l, &counter->events_list); + } + + /* Search for data item in the list */ + list_for_each_entry(data_item, &event_item->data_list, l) + if (data_item->owner == cfg->owner && + data_item->data.count_u8_read == cfg->data.count_u8_read) { + err = -EINVAL; + goto err_data_item; + } + + /* Allocate data item */ + data_item = kmalloc(sizeof(*data_item), GFP_ATOMIC); + if (!data_item) { + err = -ENOMEM; + goto err_data_item; + } + *data_item = *cfg; + + /* Add data item to event item */ + list_add_tail(&data_item->l, &event_item->data_list); + + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + + return 0; + +err_data_item: + if (list_empty(&event_item->data_list)) { + list_del(&event_item->l); + kfree(event_item); + } +err_event_item: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + return err; +} + +static int counter_set_watch(struct counter_device *const counter, + const unsigned long arg) +{ + void __user *const uwatch = (void __user *)arg; + struct counter_watch watch; + struct counter_data_item data_item; + size_t owner_id, id; + struct counter_data *ext; + size_t num_ext; + + if (copy_from_user(&watch, uwatch, sizeof(watch))) + return -EFAULT; + owner_id = watch.component.owner_id; + id = watch.component.id; + + /* Configure owner info for data item */ + switch (watch.component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + data_item.owner = NULL; + + ext = counter->ext; + num_ext = counter->num_ext; + break; + case COUNTER_OWNER_TYPE_SIGNAL: + if (counter->num_signals < owner_id + 1) + return -EINVAL; + + data_item.owner = counter->signals + owner_id; + + ext = counter->signals[owner_id].ext; + num_ext = counter->signals[owner_id].num_ext; + break; + case COUNTER_OWNER_TYPE_COUNT: + if (counter->num_counts < owner_id + 1) + return -EINVAL; + + data_item.owner = counter->counts + owner_id; + + ext = counter->counts[owner_id].ext; + num_ext = counter->counts[owner_id].num_ext; + break; + default: + return -EINVAL; + } + + /* Configure component info for data item */ + switch (watch.component.type) { + case COUNTER_COMPONENT_TYPE_SIGNAL: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_SIGNAL) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_SIGNAL; + data_item.data.signal_u8_read = counter->signal_read; + break; + case COUNTER_COMPONENT_TYPE_COUNT: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_U64; + data_item.data.count_u64_read = counter->count_read; + break; + case COUNTER_COMPONENT_TYPE_COUNT_FUNCTION: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_COUNT_FUNCTION; + data_item.data.count_u8_read = counter->function_read; + break; + case COUNTER_COMPONENT_TYPE_SYNAPSE_ACTION: + if (watch.component.owner_type != COUNTER_OWNER_TYPE_COUNT) + return -EINVAL; + if (counter->counts[owner_id].num_synapses < id + 1) + return -EINVAL; + + data_item.data.type = COUNTER_DATA_TYPE_SYNAPSE_ACTION; + data_item.data.action_read = counter->action_read; + data_item.data.priv = counter->counts[owner_id].synapses + id; + break; + case COUNTER_COMPONENT_TYPE_EXTENSION: + if (num_ext < id + 1) + return -EINVAL; + + data_item.data = ext[id]; + break; + default: + return -EINVAL; + } + if (!data_item.data.count_u8_read) + return -EFAULT; + data_item.component = watch.component; + + return counter_set_event_item(counter, watch.event, &data_item); +} + +static long counter_chrdev_ioctl(struct file *filp, unsigned int cmd, + unsigned long arg) +{ + struct counter_device *const counter = filp->private_data; + + switch (cmd) { + case COUNTER_CLEAR_WATCHES_IOCTL: + counter_events_list_free(counter); + break; + case COUNTER_SET_WATCH_IOCTL: + return counter_set_watch(counter, arg); + default: + return -ENOIOCTLCMD; + } + + return 0; +} + +static int counter_chrdev_open(struct inode *inode, struct file *filp) +{ + struct counter_device *const counter = container_of(inode->i_cdev, + typeof(*counter), + chrdev); + + 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; + + put_device(&counter->dev); + + counter_events_list_free(counter); + + return 0; +} + +static const struct file_operations counter_fops = { + .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, + const dev_t counter_devt) +{ + struct device *const dev = &counter->dev; + struct cdev *const chrdev = &counter->chrdev; + + /* Initialize Counter events list */ + INIT_LIST_HEAD(&counter->events_list); + raw_spin_lock_init(&counter->events_lock); + + /* Initialize Counter events queue */ + INIT_KFIFO(counter->events); + init_waitqueue_head(&counter->events_wait); + + /* Initialize character device */ + cdev_init(chrdev, &counter_fops); + dev->devt = MKDEV(MAJOR(counter_devt), counter->id); + cdev_set_parent(chrdev, &dev->kobj); + + return cdev_add(chrdev, dev->devt, 1); +} + +void counter_chrdev_free(struct counter_device *const counter) +{ + cdev_del(&counter->chrdev); +} + +static int counter_get_data(struct counter_device *const counter, + const struct counter_data_item *const data_item, + void *const value) +{ + const struct counter_data *const data = &data_item->data; + void *const owner = data_item->owner; + + switch (data->type) { + case COUNTER_DATA_TYPE_U8: + case COUNTER_DATA_TYPE_BOOL: + case COUNTER_DATA_TYPE_SIGNAL: + case COUNTER_DATA_TYPE_COUNT_FUNCTION: + case COUNTER_DATA_TYPE_ENUM: + case COUNTER_DATA_TYPE_COUNT_DIRECTION: + case COUNTER_DATA_TYPE_COUNT_MODE: + switch (data_item->component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + return data->device_u8_read(counter, value); + case COUNTER_OWNER_TYPE_SIGNAL: + return data->signal_u8_read(counter, owner, value); + case COUNTER_OWNER_TYPE_COUNT: + return data->count_u8_read(counter, owner, value); + } + break; + case COUNTER_DATA_TYPE_U64: + switch (data_item->component.owner_type) { + case COUNTER_OWNER_TYPE_DEVICE: + return data->device_u64_read(counter, value); + case COUNTER_OWNER_TYPE_SIGNAL: + return data->signal_u64_read(counter, owner, value); + case COUNTER_OWNER_TYPE_COUNT: + return data->count_u64_read(counter, owner, value); + } + break; + case COUNTER_DATA_TYPE_SYNAPSE_ACTION: + return data->action_read(counter, owner, data->priv, value); + } + + return 0; +} + +/** + * counter_push_event - queue event for userspace reading + * @counter: pointer to Counter structure + * @event: triggered event + * + * Note: If no one is watching for the respective event, it is silently + * discarded. + * + * RETURNS: + * 0 on success, negative error number on failure. + */ +int counter_push_event(struct counter_device *const counter, const u8 event) +{ + struct counter_event ev = { .watch.event = event }; + unsigned int copied = 0; + unsigned long flags; + struct counter_event_item *event_item; + struct counter_data_item *data_item; + int err; + + ev.timestamp = ktime_get_ns(); + + raw_spin_lock_irqsave(&counter->events_lock, flags); + + /* Search for event in the list */ + list_for_each_entry(event_item, &counter->events_list, l) + if (event_item->event == event) + break; + + /* If event is not in the list */ + if (&event_item->l == &counter->events_list) + goto exit_early; + + /* Read and queue relevant data for userspace */ + list_for_each_entry(data_item, &event_item->data_list, l) { + err = counter_get_data(counter, data_item, &ev.value_u8); + if (err) + goto err_counter_get_data; + + ev.watch.component = data_item->component; + + copied += kfifo_put(&counter->events, ev); + } + + if (copied) + wake_up_poll(&counter->events_wait, EPOLLIN); + +exit_early: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + + return 0; + +err_counter_get_data: + raw_spin_unlock_irqrestore(&counter->events_lock, flags); + return err; +} +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..7ab0797d3857 --- /dev/null +++ b/drivers/counter/counter-chrdev.h @@ -0,0 +1,16 @@ +/* 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 +#include + +int counter_chrdev_add(struct counter_device *const counter, + const dev_t counter_devt); +void counter_chrdev_free(struct counter_device *const counter); + +#endif /* _COUNTER_CHRDEV_H_ */ diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c index 499664809c75..d9ae889a0a8c 100644 --- a/drivers/counter/counter-core.c +++ b/drivers/counter/counter-core.c @@ -5,12 +5,16 @@ */ #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 */ @@ -33,6 +37,8 @@ static struct bus_type counter_bus_type = { .name = "counter" }; +static dev_t counter_devt; + /** * counter_register - register Counter to the system * @counter: pointer to Counter to register @@ -62,10 +68,15 @@ int counter_register(struct counter_device *const counter) device_initialize(dev); dev_set_drvdata(dev, counter); + /* Add Counter character device */ + err = counter_chrdev_add(counter, counter_devt); + if (err) + goto err_free_id; + /* Add Counter sysfs attributes */ err = counter_sysfs_add(counter); if (err) - goto err_free_id; + goto err_free_chrdev; /* Add device to system */ err = device_add(dev); @@ -76,6 +87,8 @@ int counter_register(struct counter_device *const counter) err_free_sysfs: counter_sysfs_free(counter); +err_free_chrdev: + counter_chrdev_free(counter); err_free_id: ida_simple_remove(&counter_ida, counter->id); return err; @@ -93,6 +106,7 @@ void counter_unregister(struct counter_device *const counter) if (counter) { device_del(&counter->dev); counter_sysfs_free(counter); + counter_chrdev_free(counter); } } EXPORT_SYMBOL_GPL(counter_unregister); @@ -139,13 +153,30 @@ 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 76657d203a26..d4f2f2463ea3 100644 --- a/include/linux/counter.h +++ b/include/linux/counter.h @@ -6,10 +6,14 @@ #ifndef _COUNTER_H_ #define _COUNTER_H_ +#include #include #include +#include #include +#include #include +#include #include struct counter_device; @@ -166,6 +170,11 @@ struct counter_attribute_group { * @priv: optional private data supplied by driver * @id: unique ID used to identify the Counter * @dev: internal device structure + * @chrdev: internal character device structure + * @events_list: list for Counter events + * @events_lock: synchronization lock for Counter events + * @events_wait: wait queue to allow blocking reads of Counter events + * @events: queue of detected Counter events * @dynamic_names_list: list for dynamically allocated names * @groups_list: attribute groups list (for Signals, Counts, and ext) * @num_groups: number of attribute groups containers @@ -204,6 +213,11 @@ struct counter_device { int id; struct device dev; + struct cdev chrdev; + struct list_head events_list; + raw_spinlock_t events_lock; + wait_queue_head_t events_wait; + DECLARE_KFIFO(events, struct counter_event, 64); struct list_head dynamic_names_list; struct counter_attribute_group *groups_list; size_t num_groups; @@ -216,6 +230,7 @@ int devm_counter_register(struct device *dev, struct counter_device *const counter); void devm_counter_unregister(struct device *dev, struct counter_device *const counter); +int counter_push_event(struct counter_device *const counter, const u8 event); #define COUNTER_DATA_DEVICE_U8(_name, _read, _write) \ { \ diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h index 2ddee9fc93e0..b903d2ad9a94 100644 --- a/include/uapi/linux/counter.h +++ b/include/uapi/linux/counter.h @@ -6,10 +6,62 @@ #ifndef _UAPI_COUNTER_H_ #define _UAPI_COUNTER_H_ +#include +#include + #define COUNTER_OWNER_TYPE_DEVICE 0 #define COUNTER_OWNER_TYPE_SIGNAL 1 #define COUNTER_OWNER_TYPE_COUNT 2 +#define COUNTER_COMPONENT_TYPE_SIGNAL 0 +#define COUNTER_COMPONENT_TYPE_COUNT 1 +#define COUNTER_COMPONENT_TYPE_COUNT_FUNCTION 2 +#define COUNTER_COMPONENT_TYPE_SYNAPSE_ACTION 3 +#define COUNTER_COMPONENT_TYPE_EXTENSION 4 + +/** + * struct counter_component - Counter component identification + * @owner_type: owner type (Device, Count, or Signal) + * @owner_id: owner identification number + * @type: component type (Count, extension, etc.) + * @id: component identification number + */ +struct counter_component { + __u8 owner_type; + __u64 owner_id; + __u8 type; + __u64 id; +}; + +/** + * struct counter_watch - Counter component watch configuration + * @event: event that triggers + * @component: component to watch when event triggers + */ +struct counter_watch { + __u8 event; + struct counter_component component; +}; + +#define COUNTER_CLEAR_WATCHES_IOCTL _IO(0x3E, 0x00) +#define COUNTER_SET_WATCH_IOCTL _IOW(0x3E, 0x01, struct counter_watch) + +/** + * struct counter_event - Counter event data + * @timestamp: best estimate of time of event occurrence, in nanoseconds + * @watch: component watch configuration + * @value_u8: component value as __u8 data type + * @value_u64: component value as __u64 data type + */ +struct counter_event { + __u64 timestamp; + struct counter_watch watch; + union { + __u8 value_u8; + __u64 value_u64; + }; +}; + #define COUNTER_COUNT_DIRECTION_FORWARD 0 #define COUNTER_COUNT_DIRECTION_BACKWARD 1 -- 2.27.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel