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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /drivers/counter/counter-chrdev.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/counter/counter-chrdev.c')
-rw-r--r--drivers/counter/counter-chrdev.c676
1 files changed, 676 insertions, 0 deletions
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
new file mode 100644
index 000000000..afc94d006
--- /dev/null
+++ b/drivers/counter/counter-chrdev.c
@@ -0,0 +1,676 @@
+// 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/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 || \
+ a.signal_array_u32_read == b.signal_array_u32_read || \
+ a.device_array_u64_read == b.device_array_u64_read || \
+ a.count_array_u64_read == b.count_array_u64_read || \
+ a.signal_array_u64_read == b.signal_array_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 || \
+ comp.signal_array_u32_read || \
+ comp.device_array_u64_read || \
+ comp.count_array_u64_read || \
+ comp.signal_array_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_out_lock))
+ return -ERESTARTSYS;
+ err = kfifo_to_user(&counter->events, buf, len, &copied);
+ mutex_unlock(&counter->events_out_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_get_ext(const struct counter_comp *const ext,
+ const size_t num_ext, const size_t component_id,
+ size_t *const ext_idx, size_t *const id)
+{
+ struct counter_array *element;
+
+ *id = 0;
+ for (*ext_idx = 0; *ext_idx < num_ext; (*ext_idx)++) {
+ if (*id == component_id)
+ return 0;
+
+ if (ext[*ext_idx].type == COUNTER_COMP_ARRAY) {
+ element = ext[*ext_idx].priv;
+
+ if (component_id - *id < element->length)
+ return 0;
+
+ *id += element->length;
+ } else
+ (*id)++;
+ }
+
+ return -EINVAL;
+}
+
+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;
+ size_t ext_idx, ext_id;
+ 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:
+ err = counter_get_ext(ext, num_ext, id, &ext_idx, &ext_id);
+ if (err < 0)
+ return err;
+
+ comp_node.comp = ext[ext_idx];
+ 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);
+
+ 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);
+
+ 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);
+ spin_lock_init(&counter->events_in_lock);
+ mutex_init(&counter->events_out_lock);
+
+ /* Initialize character device */
+ 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_array_data(struct counter_device *const counter,
+ const enum counter_scope scope,
+ void *const parent,
+ const struct counter_comp *const comp,
+ const size_t idx, u64 *const value)
+{
+ const struct counter_array *const element = comp->priv;
+ u32 value_u32 = 0;
+ int ret;
+
+ switch (element->type) {
+ case COUNTER_COMP_SIGNAL_POLARITY:
+ if (scope != COUNTER_SCOPE_SIGNAL)
+ return -EINVAL;
+ ret = comp->signal_array_u32_read(counter, parent, idx,
+ &value_u32);
+ *value = value_u32;
+ return ret;
+ case COUNTER_COMP_U64:
+ switch (scope) {
+ case COUNTER_SCOPE_DEVICE:
+ return comp->device_array_u64_read(counter, idx, value);
+ case COUNTER_SCOPE_SIGNAL:
+ return comp->signal_array_u64_read(counter, parent, idx,
+ value);
+ case COUNTER_SCOPE_COUNT:
+ return comp->count_array_u64_read(counter, parent, idx,
+ value);
+ default:
+ return -EINVAL;
+ }
+ default:
+ return -EINVAL;
+ }
+}
+
+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;
+ const enum counter_scope scope = comp_node->component.scope;
+ const size_t id = comp_node->component.id;
+ struct counter_signal *const signal = comp_node->parent;
+ struct counter_count *const count = comp_node->parent;
+ u8 value_u8 = 0;
+ u32 value_u32 = 0;
+ const struct counter_comp *ext;
+ size_t num_ext;
+ size_t ext_idx, ext_id;
+ int ret;
+
+ if (comp_node->component.type == COUNTER_COMPONENT_NONE)
+ return 0;
+
+ switch (comp->type) {
+ case COUNTER_COMP_U8:
+ case COUNTER_COMP_BOOL:
+ switch (scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ret = comp->device_u8_read(counter, &value_u8);
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ ret = comp->signal_u8_read(counter, signal, &value_u8);
+ break;
+ case COUNTER_SCOPE_COUNT:
+ ret = comp->count_u8_read(counter, count, &value_u8);
+ break;
+ default:
+ return -EINVAL;
+ }
+ *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:
+ case COUNTER_COMP_SIGNAL_POLARITY:
+ switch (scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ret = comp->device_u32_read(counter, &value_u32);
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ ret = comp->signal_u32_read(counter, signal,
+ &value_u32);
+ break;
+ case COUNTER_SCOPE_COUNT:
+ ret = comp->count_u32_read(counter, count, &value_u32);
+ break;
+ default:
+ return -EINVAL;
+ }
+ *value = value_u32;
+ return ret;
+ case COUNTER_COMP_U64:
+ switch (scope) {
+ case COUNTER_SCOPE_DEVICE:
+ return comp->device_u64_read(counter, value);
+ case COUNTER_SCOPE_SIGNAL:
+ return comp->signal_u64_read(counter, signal, value);
+ case COUNTER_SCOPE_COUNT:
+ return comp->count_u64_read(counter, count, value);
+ default:
+ return -EINVAL;
+ }
+ case COUNTER_COMP_SYNAPSE_ACTION:
+ ret = comp->action_read(counter, count, comp->priv, &value_u32);
+ *value = value_u32;
+ return ret;
+ case COUNTER_COMP_ARRAY:
+ switch (scope) {
+ case COUNTER_SCOPE_DEVICE:
+ ext = counter->ext;
+ num_ext = counter->num_ext;
+ break;
+ case COUNTER_SCOPE_SIGNAL:
+ ext = signal->ext;
+ num_ext = signal->num_ext;
+ break;
+ case COUNTER_SCOPE_COUNT:
+ ext = count->ext;
+ num_ext = count->num_ext;
+ break;
+ default:
+ return -EINVAL;
+ }
+ ret = counter_get_ext(ext, num_ext, id, &ext_idx, &ext_id);
+ if (ret < 0)
+ return ret;
+
+ return counter_get_array_data(counter, scope, comp_node->parent,
+ comp, id - ext_id, value);
+ 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_spinlocked_noirqsave(&counter->events, &ev,
+ 1, &counter->events_in_lock);
+ }
+
+exit_early:
+ spin_unlock_irqrestore(&counter->events_list_lock, flags);
+
+ if (copied)
+ wake_up_poll(&counter->events_wait, EPOLLIN);
+}
+EXPORT_SYMBOL_NS_GPL(counter_push_event, COUNTER);