Verified Commit 4359f43b authored by Felix Kopp's avatar Felix Kopp
Browse files

kevent: refactor callback system

parent 30404f60
......@@ -134,11 +134,8 @@ void irq_uart(void)
tmp = REG_UART_RHR;
ringbuf_write(arch_serial_default_device.device.rx, &tmp, sizeof(tmp));
/* TODO: we need some error handling mechanism for event creation */
struct device_kevent *event = device_kevent_create(&serial_default_device->device,
DEVICE_CHANNEL_IN);
if (event != NULL)
kevent_dispatch(&event->event);
device_kevent_create_and_dispatch(&serial_default_device->device,
DEVICE_CHANNEL_IN);
}
/* REG_UART_PDC_TCR has reached zero */
......@@ -153,11 +150,8 @@ void irq_uart(void)
if (arch_serial_default_device.tx_current == NULL)
REG_UART_IDR = REG_UART_IDR_ENDTX_MASK;
/* TODO: we need some error handling mechanism for event creation */
struct device_kevent *event = device_kevent_create(&serial_default_device->device,
DEVICE_CHANNEL_OUT);
if (event != NULL)
kevent_dispatch(&event->event);
device_kevent_create_and_dispatch(&serial_default_device->device,
DEVICE_CHANNEL_OUT);
}
/* check for error conditions */
......
......@@ -50,6 +50,14 @@ __always_inline struct device *kevent_to_device(struct kevent *event)
*/
struct device_kevent *device_kevent_create(struct device *device, enum device_channel channel);
/**
* @brief Convenience wrapper for creating and immediately dispatching a device kevent.
*
* @param device Device the event refers to
* @param channel Which channel (in or out) the event applies to
*/
void device_kevent_create_and_dispatch(struct device *device, enum device_channel channel);
/** Initialize the devices subsystem. */
int devices_init(void);
......
......@@ -36,6 +36,31 @@ struct kevent {
enum kevent_kind kind;
};
/**
* @brief Flags for kevent callback return values.
*/
enum kevent_cb_flags {
/** @brief No particular action is taken. */
KEVENT_CB_NONE = 0,
/** @brief Stop processing the other callbacks in the queue after the callback. */
KEVENT_CB_STOP = (1 << 0),
/** @brief Call `kevent_listener_del()` after the callback. */
KEVENT_CB_LISTENER_DEL = (1 << 1),
};
/**
* @brief Identifies a single kevent listener.
*
* This is returned by `kevent_listener_add()` and must be passed to
* `kevent_listener_del()` when the listener is no longer needed.
* You shouldn't modify the members yourself.
*/
struct kevent_listener {
struct list_head link;
int (*cb)(struct kevent *event, void *extra);
void *extra;
};
/** @brief Initialize the kevent subsystem. */
void kevents_init(void);
......@@ -55,27 +80,24 @@ void kevent_dispatch(struct kevent *event);
/**
* @brief Add an event listener to the end of the listener queue.
* The callback will be invoked for every event that is dispatched and matches
* the event kind. If its return value is nonzero, event handler processing
* stops after that callback. This is useful if you know for sure that you are
* the only one interested in the event, for example when waiting for I/O.
* the event kind. The return value of this callback is a set of flags, see
* `enum kevent_cb_flags` for details.
*
* @param kind Kind of kevent to listen for
* @param cb Callback that will be invoked for every kevent that is dispatched
* @param extra An optional extra pointer that will be passed to the callback
* @returns 0 on success, or a negtive error number on failure
* @returns The listener (pass to `kevent_listener_del()` when no longer needed)
*/
int kevent_add_listener(enum kevent_kind kind,
int (*cb)(struct kevent *event, void *extra),
void *extra);
struct kevent_listener *kevent_listener_add(enum kevent_kind kind,
int (*cb)(struct kevent *event, void *extra),
void *extra);
/**
* @brief Remove an event listener.
*
* @param kind Kind that was passed to `kevent_add_listener()`
* @param cb Callback that was passed to `kevent_add_listener()`
* @param listener The listener returned by `kevent_listener_add()`
*/
void kevent_remove_listener(enum kevent_kind kind,
int (*cb)(struct kevent *event, void *extra));
void kevent_listener_del(struct kevent_listener *listener);
__always_inline void kevent_get(struct kevent *event)
{
......
......@@ -77,6 +77,13 @@ struct device_kevent *device_kevent_create(struct device *device, enum device_ch
return event;
}
void device_kevent_create_and_dispatch(struct device *device, enum device_channel channel)
{
struct device_kevent *event = device_kevent_create(device, channel);
if (event != NULL)
kevent_dispatch(&event->event);
}
/*
* This file is part of Ardix.
* Copyright (c) 2020, 2021 Felix Kopp <owo@fef.moe>.
......
......@@ -31,20 +31,13 @@ static struct kevent_queue kev_queues[KEVENT_KIND_COUNT];
/**
* irqs cannot sleep or block, so we can only *try* to claim the lock on
* an event queue when dispatching an event. If this fails (which shouldn't
* an event queue when dispatching an event. If this fails (which should
* happen only rarely), we store the event in this (unsorted) pile and sort them
* out before processing the event queue. We technically need a lock for this
* queue as well, but that's okay because we don't
* out before processing the event queue.
*/
LIST_HEAD(kev_cache);
MUTEX(kev_cache_lock);
struct kevent_listener {
struct list_head link; /* -> kevent_queue::list */
void *extra;
int (*cb)(struct kevent *event, void *extra);
};
void kevents_init(void)
{
for (int i = 0; i < KEVENT_KIND_COUNT; i++) {
......@@ -71,7 +64,13 @@ static inline void process_single_queue(struct kevent_queue *queue, struct list_
list_for_each_entry(listeners, listener, link) {
int cb_ret = listener->cb(event, listener->extra);
if (cb_ret != 0)
if (cb_ret & KEVENT_CB_LISTENER_DEL) {
list_delete(&listener->link);
free(listener);
}
if (cb_ret & KEVENT_CB_STOP)
break;
}
......@@ -149,36 +148,31 @@ void kevent_dispatch(struct kevent *event)
}
}
int kevent_add_listener(enum kevent_kind kind, int (*cb)(struct kevent *, void *), void *extra)
struct kevent_listener *kevent_listener_add(enum kevent_kind kind,
int (*cb)(struct kevent *, void *),
void *extra)
{
struct kevent_listener *listener = malloc(sizeof(*listener));
if (listener == NULL)
return -ENOMEM;
listener->cb = cb;
listener->extra = extra;
if (listener != NULL) {
listener->cb = cb;
listener->extra = extra;
mutex_lock(&kev_listeners_lock);
list_insert(&kev_listeners[kind], &listener->link);
mutex_unlock(&kev_listeners_lock);
mutex_lock(&kev_listeners_lock);
list_insert(&kev_listeners[kind], &listener->link);
mutex_unlock(&kev_listeners_lock);
}
return 0;
return listener;
}
void kevent_remove_listener(enum kevent_kind kind, int (*cb)(struct kevent *, void *))
void kevent_listener_del(struct kevent_listener *listener)
{
struct kevent_listener *listener, *tmp;
list_for_each_entry_safe(&kev_listeners[kind], listener, tmp, link) {
if (listener->cb == cb) {
mutex_lock(&kev_listeners_lock);
list_delete(&listener->link);
mutex_unlock(&kev_listeners_lock);
mutex_lock(&kev_listeners_lock);
list_delete(&listener->link);
mutex_unlock(&kev_listeners_lock);
free(listener);
break;
}
}
free(listener);
}
/*
......
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