@@ -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
new file mode 100644
@@ -0,0 +1,578 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Generic Counter character device interface
+ * Copyright (C) 2020 William Breathitt Gray
+ */
+#include <linux/atomic.h>
+#include <linux/cdev.h>
+#include <linux/counter.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/fs.h>
+#include <linux/kfifo.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/nospec.h>
+#include <linux/poll.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/timekeeping.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/wait.h>
+
+#include "counter-chrdev.h"
+
+struct counter_comp_node {
+ struct list_head l;
+ struct counter_component component;
+ struct counter_comp comp;
+ void *parent;
+};
+
+#define counter_comp_read_is_equal(a, b) \
+ (a.action_read == b.action_read || \
+ a.device_u8_read == b.device_u8_read || \
+ a.count_u8_read == b.count_u8_read || \
+ a.signal_u8_read == b.signal_u8_read || \
+ a.device_u32_read == b.device_u32_read || \
+ a.count_u32_read == b.count_u32_read || \
+ a.signal_u32_read == b.signal_u32_read || \
+ a.device_u64_read == b.device_u64_read || \
+ a.count_u64_read == b.count_u64_read || \
+ a.signal_u64_read == b.signal_u64_read)
+
+#define counter_comp_read_is_set(comp) \
+ (comp.action_read || \
+ comp.device_u8_read || \
+ comp.count_u8_read || \
+ comp.signal_u8_read || \
+ comp.device_u32_read || \
+ comp.count_u32_read || \
+ comp.signal_u32_read || \
+ comp.device_u64_read || \
+ comp.count_u64_read || \
+ comp.signal_u64_read)
+
+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 &&
+ counter_comp_read_is_equal(comp_node->comp, cfg->comp)) {
+ 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;
+ }
+ if (!counter_comp_read_is_set(comp_node.comp))
+ 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);
+
+ /* Ensure chrdev is not opened more than 1 at a time */
+ if (!atomic_add_unless(&counter->chrdev_lock, 1, 1))
+ 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) {
+ /* Free any lingering held memory */
+ 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);
+ atomic_dec(&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 */
+ atomic_set(&counter->chrdev_lock, 0);
+ 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);
new file mode 100644
@@ -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 <linux/counter.h>
+
+int counter_chrdev_add(struct counter_device *const counter);
+void counter_chrdev_remove(struct counter_device *const counter);
+
+#endif /* _COUNTER_CHRDEV_H_ */
@@ -3,14 +3,22 @@
* Generic Counter interface
* Copyright (C) 2020 William Breathitt Gray
*/
+#include <linux/cdev.h>
#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/kdev_t.h>
#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+#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);
if (err < 0)
goto err_free_id;
- /* Add device to system */
- err = device_add(dev);
+ err = counter_chrdev_add(counter);
if (err < 0)
goto err_free_id;
+ 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);
}
@@ -6,9 +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/mutex.h>
+#include <linux/spinlock_types.h>
#include <linux/types.h>
+#include <linux/wait.h>
#include <uapi/linux/counter.h>
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 +317,29 @@ 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;
+ /*
+ * chrdev_lock is locked by counter_chrdev_open() and unlocked by
+ * counter_chrdev_release(), so a mutex is not possible here because
+ * chrdev_lock will invariably be held when returning to user space
+ */
+ atomic_t chrdev_lock;
+ 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) \
{ \
@@ -6,6 +6,19 @@
#ifndef _UAPI_COUNTER_H_
#define _UAPI_COUNTER_H_
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+/* 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,
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 <david@lechnology.com> Cc: Gwendal Grignou <gwendal@chromium.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Oleksij Rempel <o.rempel@pengutronix.de> Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com> --- drivers/counter/Makefile | 2 +- drivers/counter/counter-chrdev.c | 578 +++++++++++++++++++++++++++++++ drivers/counter/counter-chrdev.h | 14 + drivers/counter/counter-core.c | 56 ++- include/linux/counter.h | 56 +++ include/uapi/linux/counter.h | 98 ++++++ 6 files changed, 798 insertions(+), 6 deletions(-) create mode 100644 drivers/counter/counter-chrdev.c create mode 100644 drivers/counter/counter-chrdev.h