[PATCH v4 3/5] counter: Add character device interface
William Breathitt Gray
vilhelm.gray at gmail.com
Tue Jul 21 15:35:49 EDT 2020
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 <fcntl.h>
#include <linux/counter.h>
#include <poll.h>
#include <stdio.h>
#include <sys/ioctl.h>
#include <unistd.h>
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 <david at lechnology.com>
Cc: Gwendal Grignou <gwendal at chromium.org>
Signed-off-by: William Breathitt Gray <vilhelm.gray at gmail.com>
---
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 <linux/cdev.h>
+#include <linux/counter.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/list.h>
+#include <linux/poll.h>
+#include <linux/kdev_t.h>
+#include <linux/kfifo.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#include <linux/uaccess.h>
+
+#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 <linux/counter.h>
+#include <linux/types.h>
+
+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 <linux/counter.h>
#include <linux/device.h>
+#include <linux/device/bus.h>
#include <linux/export.h>
+#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/idr.h>
#include <linux/init.h>
#include <linux/module.h>
+#include <linux/types.h>
+#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 <linux/cdev.h>
#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/kfifo.h>
#include <linux/list.h>
+#include <linux/spinlock_types.h>
#include <linux/types.h>
+#include <linux/wait.h>
#include <uapi/linux/counter.h>
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 <linux/ioctl.h>
+#include <linux/types.h>
+
#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
More information about the linux-arm-kernel
mailing list