notify.h File Reference

#include <uacpi/types.h>

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Functions
uacpi_status	uacpi_install_notify_handler (uacpi_namespace_node *node, uacpi_notify_handler handler, uacpi_handle handler_context)
uacpi_status	uacpi_uninstall_notify_handler (uacpi_namespace_node *node, uacpi_notify_handler handler)

Function Documentation

uacpi_install_notify_handler()

uacpi_status uacpi_install_notify_handler	(	uacpi_namespace_node *	node,
		uacpi_notify_handler	handler,
		uacpi_handle	handler_context
	)

Install a Notify() handler to a device node. A handler installed to the root node will receive all notifications, even if a device already has a dedicated Notify handler. 'handler_context' is passed to the handler on every invocation.

Definition at line 182 of file notify.c.

{
    uacpi_status ret;
    uacpi_object *obj;
    uacpi_handlers *handlers;
    uacpi_device_notify_handler *new_handler;
 
    UACPI_ENSURE_INIT_LEVEL_AT_LEAST(UACPI_INIT_LEVEL_SUBSYSTEM_INITIALIZED);
 
    if (node == uacpi_namespace_root()) {
        obj = g_uacpi_rt_ctx.root_object;
    } else {
        ret = uacpi_namespace_node_acquire_object_typed(
            node, UACPI_OBJECT_DEVICE_BIT | UACPI_OBJECT_THERMAL_ZONE_BIT |
                  UACPI_OBJECT_PROCESSOR_BIT, &obj
        );
        if (uacpi_unlikely_error(ret))
            return ret;
    }
 
    ret = uacpi_acquire_native_mutex(notify_mutex);
    if (uacpi_unlikely_error(ret))
        goto out_no_mutex;
 
    handlers = obj->handlers;
 
    if (handler_container(handlers, handler) != UACPI_NULL) {
        ret = UACPI_STATUS_ALREADY_EXISTS;
        goto out;
    }
 
    new_handler = uacpi_kernel_alloc_zeroed(sizeof(*new_handler));
    if (uacpi_unlikely(new_handler == UACPI_NULL)) {
        ret = UACPI_STATUS_OUT_OF_MEMORY;
        goto out;
    }
 
    new_handler->callback = handler;
    new_handler->user_context = handler_context;
    new_handler->next = handlers->notify_head;
 
    uacpi_atomic_store_ptr(&handlers->notify_head, new_handler);
 
out:
    uacpi_release_native_mutex(notify_mutex);
out_no_mutex:
    if (node != uacpi_namespace_root())
        uacpi_object_unref(obj);
 
    return ret;
}

uacpi_uninstall_notify_handler()

uacpi_status uacpi_uninstall_notify_handler	(	uacpi_namespace_node *	node,
		uacpi_notify_handler	handler
	)

Uninstall a Notify() handler previously installed to a device node. The handler is guaranteed to not be running, and to never be invoked again once this function returns.

NOTE: this waits for all of the in-flight notifications to complete, and therefore must not be called from a notify handler, any other work scheduled via uacpi_kernel_schedule_work, an address space handler, or with the global lock held.

Definition at line 237 of file notify.c.

{
    uacpi_status ret;
    uacpi_object *obj;
    uacpi_handlers *handlers;
    uacpi_device_notify_handler *prev_handler, *containing = UACPI_NULL;
 
    UACPI_ENSURE_INIT_LEVEL_AT_LEAST(UACPI_INIT_LEVEL_SUBSYSTEM_INITIALIZED);
 
    if (node == uacpi_namespace_root()) {
        obj = g_uacpi_rt_ctx.root_object;
    } else {
        ret = uacpi_namespace_node_acquire_object_typed(
            node, UACPI_OBJECT_DEVICE_BIT | UACPI_OBJECT_THERMAL_ZONE_BIT |
                  UACPI_OBJECT_PROCESSOR_BIT, &obj
        );
        if (uacpi_unlikely_error(ret))
            return ret;
    }
 
    ret = uacpi_acquire_native_mutex(notify_mutex);
    if (uacpi_unlikely_error(ret))
        goto out_no_mutex;
 
    handlers = obj->handlers;
 
    containing = handler_container(handlers, handler);
    if (containing == UACPI_NULL) {
        ret = UACPI_STATUS_NOT_FOUND;
        goto out;
    }
 
    prev_handler = handlers->notify_head;
 
    // Are we the last linked handler?
    if (prev_handler == containing) {
        uacpi_atomic_store_ptr(&handlers->notify_head, containing->next);
        goto out;
    }
 
    // Nope, we're somewhere in the middle. Do a search.
    while (prev_handler) {
        if (prev_handler->next == containing) {
            uacpi_atomic_store_ptr(&prev_handler->next, containing->next);
            goto out;
        }
 
        prev_handler = prev_handler->next;
    }
 
out:
    uacpi_release_native_mutex(notify_mutex);
out_no_mutex:
    if (node != uacpi_namespace_root())
        uacpi_object_unref(obj);
 
    if (uacpi_likely_success(ret)) {
        /*
         * The handler is no longer reachable, but a notification that started
         * before we unlinked it might still be about to call it. Wait for
         * those to finish, this also guarantees that the handler is never
         * invoked again after we return.
         *
         * This must be done without the notify mutex held: the work that we
         * are waiting for needs it in order to dispatch a Notify().
         */
        uacpi_kernel_wait_for_work_completion();
        uacpi_free(containing, sizeof(*containing));
    }
 
    return ret;
}