/*
 *   BSD LICENSE
 *
 *   Copyright 2016 Cavium.
 *   Copyright 2016 Intel Corporation.
 *   Copyright 2016 NXP.
 *
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 *   modification, are permitted provided that the following conditions
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 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
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 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
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#ifndef _RTE_EVENTDEV_H_
#define _RTE_EVENTDEV_H_

/**
 * @file
 *
 * RTE Event Device API
 *
 * The Event Device API is composed of two parts:
 *
 * - The application-oriented Event API that includes functions to setup
 *   an event device (configure it, setup its queues, ports and start it), to
 *   establish the link between queues to port and to receive events, and so on.
 *
 * - The driver-oriented Event API that exports a function allowing
 *   an event poll Mode Driver (PMD) to simultaneously register itself as
 *   an event device driver.
 *
 * Event device components:
 *
 *                     +-----------------+
 *                     | +-------------+ |
 *        +-------+    | |    flow 0   | |
 *        |Packet |    | +-------------+ |
 *        |event  |    | +-------------+ |
 *        |       |    | |    flow 1   | |event_port_link(port0, queue0)
 *        +-------+    | +-------------+ |     |     +--------+
 *        +-------+    | +-------------+ o-----v-----o        |dequeue +------+
 *        |Crypto |    | |    flow n   | |           | event  +------->|Core 0|
 *        |work   |    | +-------------+ o----+      | port 0 |        |      |
 *        |done ev|    |  event queue 0  |    |      +--------+        +------+
 *        +-------+    +-----------------+    |
 *        +-------+                           |
 *        |Timer  |    +-----------------+    |      +--------+
 *        |expiry |    | +-------------+ |    +------o        |dequeue +------+
 *        |event  |    | |    flow 0   | o-----------o event  +------->|Core 1|
 *        +-------+    | +-------------+ |      +----o port 1 |        |      |
 *       Event enqueue | +-------------+ |      |    +--------+        +------+
 *     o-------------> | |    flow 1   | |      |
 *        enqueue(     | +-------------+ |      |
 *        queue_id,    |                 |      |    +--------+        +------+
 *        flow_id,     | +-------------+ |      |    |        |dequeue |Core 2|
 *        sched_type,  | |    flow n   | o-----------o event  +------->|      |
 *        event_type,  | +-------------+ |      |    | port 2 |        +------+
 *        subev_type,  |  event queue 1  |      |    +--------+
 *        event)       +-----------------+      |    +--------+
 *                                              |    |        |dequeue +------+
 *        +-------+    +-----------------+      |    | event  +------->|Core n|
 *        |Core   |    | +-------------+ o-----------o port n |        |      |
 *        |(SW)   |    | |    flow 0   | |      |    +--------+        +--+---+
 *        |event  |    | +-------------+ |      |                         |
 *        +-------+    | +-------------+ |      |                         |
 *            ^        | |    flow 1   | |      |                         |
 *            |        | +-------------+ o------+                         |
 *            |        | +-------------+ |                                |
 *            |        | |    flow n   | |                                |
 *            |        | +-------------+ |                                |
 *            |        |  event queue n  |                                |
 *            |        +-----------------+                                |
 *            |                                                           |
 *            +-----------------------------------------------------------+
 *
 *
 *
 * Event device: A hardware or software-based event scheduler.
 *
 * Event: A unit of scheduling that encapsulates a packet or other datatype
 * like SW generated event from the core, Crypto work completion notification,
 * Timer expiry event notification etc as well as metadata.
 * The metadata includes flow ID, scheduling type, event priority, event_type,
 * sub_event_type etc.
 *
 * Event queue: A queue containing events that are scheduled by the event dev.
 * An event queue contains events of different flows associated with scheduling
 * types, such as atomic, ordered, or parallel.
 *
 * Event port: An application's interface into the event dev for enqueue and
 * dequeue operations. Each event port can be linked with one or more
 * event queues for dequeue operations.
 *
 * By default, all the functions of the Event Device API exported by a PMD
 * are lock-free functions which assume to not be invoked in parallel on
 * different logical cores to work on the same target object. For instance,
 * the dequeue function of a PMD cannot be invoked in parallel on two logical
 * cores to operates on same  event port. Of course, this function
 * can be invoked in parallel by different logical cores on different ports.
 * It is the responsibility of the upper level application to enforce this rule.
 *
 * In all functions of the Event API, the Event device is
 * designated by an integer >= 0 named the device identifier *dev_id*
 *
 * At the Event driver level, Event devices are represented by a generic
 * data structure of type *rte_event_dev*.
 *
 * Event devices are dynamically registered during the PCI/SoC device probing
 * phase performed at EAL initialization time.
 * When an Event device is being probed, a *rte_event_dev* structure and
 * a new device identifier are allocated for that device. Then, the
 * event_dev_init() function supplied by the Event driver matching the probed
 * device is invoked to properly initialize the device.
 *
 * The role of the device init function consists of resetting the hardware or
 * software event driver implementations.
 *
 * If the device init operation is successful, the correspondence between
 * the device identifier assigned to the new device and its associated
 * *rte_event_dev* structure is effectively registered.
 * Otherwise, both the *rte_event_dev* structure and the device identifier are
 * freed.
 *
 * The functions exported by the application Event API to setup a device
 * designated by its device identifier must be invoked in the following order:
 *     - rte_event_dev_configure()
 *     - rte_event_queue_setup()
 *     - rte_event_port_setup()
 *     - rte_event_port_link()
 *     - rte_event_dev_start()
 *
 * Then, the application can invoke, in any order, the functions
 * exported by the Event API to schedule events, dequeue events, enqueue events,
 * change event queue(s) to event port [un]link establishment and so on.
 *
 * Application may use rte_event_[queue/port]_default_conf_get() to get the
 * default configuration to set up an event queue or event port by
 * overriding few default values.
 *
 * If the application wants to change the configuration (i.e. call
 * rte_event_dev_configure(), rte_event_queue_setup(), or
 * rte_event_port_setup()), it must call rte_event_dev_stop() first to stop the
 * device and then do the reconfiguration before calling rte_event_dev_start()
 * again. The schedule, enqueue and dequeue functions should not be invoked
 * when the device is stopped.
 *
 * Finally, an application can close an Event device by invoking the
 * rte_event_dev_close() function.
 *
 * Each function of the application Event API invokes a specific function
 * of the PMD that controls the target device designated by its device
 * identifier.
 *
 * For this purpose, all device-specific functions of an Event driver are
 * supplied through a set of pointers contained in a generic structure of type
 * *event_dev_ops*.
 * The address of the *event_dev_ops* structure is stored in the *rte_event_dev*
 * structure by the device init function of the Event driver, which is
 * invoked during the PCI/SoC device probing phase, as explained earlier.
 *
 * In other words, each function of the Event API simply retrieves the
 * *rte_event_dev* structure associated with the device identifier and
 * performs an indirect invocation of the corresponding driver function
 * supplied in the *event_dev_ops* structure of the *rte_event_dev* structure.
 *
 * For performance reasons, the address of the fast-path functions of the
 * Event driver is not contained in the *event_dev_ops* structure.
 * Instead, they are directly stored at the beginning of the *rte_event_dev*
 * structure to avoid an extra indirect memory access during their invocation.
 *
 * RTE event device drivers do not use interrupts for enqueue or dequeue
 * operation. Instead, Event drivers export Poll-Mode enqueue and dequeue
 * functions to applications.
 *
 * An event driven based application has following typical workflow on fastpath:
 * \code{.c}
 *	while (1) {
 *
 *		rte_event_schedule(dev_id);
 *
 *		rte_event_dequeue(...);
 *
 *		(event processing)
 *
 *		rte_event_enqueue(...);
 *	}
 * \endcode
 *
 * The *schedule* operation is intended to do event scheduling, and the
 * *dequeue* operation returns the scheduled events. An implementation
 * is free to define the semantics between *schedule* and *dequeue*. For
 * example, a system based on a hardware scheduler can define its
 * rte_event_schedule() to be an NOOP, whereas a software scheduler can use
 * the *schedule* operation to schedule events.
 *
 * The events are injected to event device through *enqueue* operation by
 * event producers in the system. The typical event producers are ethdev
 * subsystem for generating packet events, core(SW) for generating events based
 * on different stages of application processing, cryptodev for generating
 * crypto work completion notification etc
 *
 * The *dequeue* operation gets one or more events from the event ports.
 * The application process the events and send to downstream event queue through
 * rte_event_enqueue() if it is an intermediate stage of event processing, on
 * the final stage, the application may send to different subsystem like ethdev
 * to send the packet/event on the wire using ethdev rte_eth_tx_burst() API.
 *
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <rte_pci.h>
#include <rte_dev.h>
#include <rte_devargs.h>
#include <rte_errno.h>

/**
 * Get the total number of event devices that have been successfully
 * initialised.
 *
 * @return
 *   The total number of usable event devices.
 */
extern uint8_t
rte_event_dev_count(void);

/**
 * Get the device identifier for the named event device.
 *
 * @param name
 *   Event device name to select the event device identifier.
 *
 * @return
 *   Returns event device identifier on success.
 *   - <0: Failure to find named event device.
 */
extern uint8_t
rte_event_dev_get_dev_id(const char *name);

/**
 * Return the NUMA socket to which a device is connected.
 *
 * @param dev_id
 *   The identifier of the device.
 * @return
 *   The NUMA socket id to which the device is connected or
 *   a default of zero if the socket could not be determined.
 *   - -1: dev_id value is out of range.
 */
extern int
rte_event_dev_socket_id(uint8_t dev_id);

/* Event device capability bitmap flags */
#define RTE_EVENT_DEV_CAP_QUEUE_QOS        (1 << 0)
/**< Event scheduling prioritization is based on the priority associated with
 *  each event queue.
 *
 *  \see rte_event_queue_setup(), RTE_EVENT_QUEUE_PRIORITY_NORMAL
 */
#define RTE_EVENT_DEV_CAP_EVENT_QOS        (1 << 1)
/**< Event scheduling prioritization is based on the priority associated with
 *  each event. Priority of each event is supplied in *rte_event* structure
 *  on each enqueue operation.
 *
 *  \see rte_event_enqueue()
 */

/**
 * Event device information
 */
struct rte_event_dev_info {
	const char *driver_name;	/**< Event driver name */
	struct rte_pci_device *pci_dev;	/**< PCI information */
	uint32_t min_dequeue_wait_ns;
	/**< Minimum supported global dequeue wait delay(ns) by this device */
	uint32_t max_dequeue_wait_ns;
	/**< Maximum supported global dequeue wait delay(ns) by this device */
	uint32_t dequeue_wait_ns;
	/**< Configured global dequeue wait delay(ns) for this device */
	uint8_t max_event_queues;
	/**< Maximum event_queues supported by this device */
	uint32_t max_event_queue_flows;
	/**< Maximum supported flows in an event queue by this device*/
	uint8_t max_event_queue_priority_levels;
	/**< Maximum number of event queue priority levels by this device.
	 * Valid when the device has RTE_EVENT_DEV_CAP_QUEUE_QOS capability
	 */
	uint8_t nb_event_queues;
	/**< Configured number of event queues for this device */
	uint8_t max_event_priority_levels;
	/**< Maximum number of event priority levels by this device.
	 * Valid when the device has RTE_EVENT_DEV_CAP_EVENT_QOS capability
         */
	uint8_t max_event_ports;
	/**< Maximum number of event ports supported by this device */
	uint8_t nb_event_ports;
	/**< Configured number of event ports for this device */
	uint8_t max_event_port_dequeue_queue_depth;
	/**< Maximum dequeue queue depth for any event port.
	 * Implementations can schedule N events at a time to an event port.
	 * A device that does not support bulk dequeue will set this as 1.
	 * \see rte_event_port_setup()
	 */
	uint32_t max_event_port_enqueue_queue_depth;
	/**< Maximum enqueue queue depth for any event port. Implementations
	 * can batch N events at a time to enqueue through event port
	 * \see rte_event_port_setup()
	 */
	int32_t max_num_events;
	/**< A *closed system* event dev has a limit on the number of events it
	 * can manage at a time. An *open system* event dev does not have a
	 * limit and will specify this as -1.
	 */
	uint32_t event_dev_cap;
	/**< Event device capabilities(RTE_EVENT_DEV_CAP_)*/
};

/**
 * Retrieve the contextual information of an event device.
 *
 * @param dev_id
 *   The identifier of the device.
 *
 * @param[out] dev_info
 *   A pointer to a structure of type *rte_event_dev_info* to be filled with the
 *   contextual information of the device.
 *
 */
extern void
rte_event_dev_info_get(uint8_t dev_id, struct rte_event_dev_info *dev_info);

/* Event device configuration bitmap flags */
#define RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT (1 << 0)
/**< Override the global *dequeue_wait_ns* and use per dequeue wait in ns.
 *  \see rte_event_dequeue_wait_time(), rte_event_dequeue()
 */

/** Event device configuration structure */
struct rte_event_dev_config {
	uint32_t dequeue_wait_ns;
	/**< rte_event_dequeue() wait for *dequeue_wait_ns* ns on this device.
	 * This value should be in the range of *min_dequeue_wait_ns* and
	 * *max_dequeue_wait_ns* which previously provided in
	 * rte_event_dev_info_get()
	 * \see RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT
	 */
	int32_t nb_events_limit;
	/**< Applies to *closed system* event dev only. This field indicates a
	 * limit to ethdev-like devices to limit the number of events injected
	 * into the system to not overwhelm core-to-core events.
	 * This value cannot exceed the *max_num_events* which previously
	 * provided in rte_event_dev_info_get()
	 */
	uint8_t nb_event_queues;
	/**< Number of event queues to configure on this device.
	 * This value cannot exceed the *max_event_queues* which previously
	 * provided in rte_event_dev_info_get()
	 */
	uint8_t nb_event_ports;
	/**< Number of event ports to configure on this device.
	 * This value cannot exceed the *max_event_ports* which previously
	 * provided in rte_event_dev_info_get()
	 */
	uint32_t event_dev_cfg;
	/**< Event device config flags(RTE_EVENT_DEV_CFG_)*/
};

/**
 * Configure an event device.
 *
 * This function must be invoked first before any other function in the
 * API. This function can also be re-invoked when a device is in the
 * stopped state.
 *
 * The caller may use rte_event_dev_info_get() to get the capability of each
 * resources available for this event device.
 *
 * @param dev_id
 *   The identifier of the device to configure.
 * @param config
 *   The event device configuration structure.
 *
 * @return
 *   - 0: Success, device configured.
 *   - <0: Error code returned by the driver configuration function.
 */
extern int
rte_event_dev_configure(uint8_t dev_id, struct rte_event_dev_config *config);


/* Event queue specific APIs */

#define RTE_EVENT_QUEUE_PRIORITY_HIGHEST   0
/**< Highest event queue priority */
#define RTE_EVENT_QUEUE_PRIORITY_NORMAL    128
/**< Normal event queue priority */
#define RTE_EVENT_QUEUE_PRIORITY_LOWEST    255
/**< Lowest event queue priority */

/* Event queue configuration bitmap flags */
#define RTE_EVENT_QUEUE_CFG_SINGLE_CONSUMER    (1 << 0)
/**< This event queue links only to a single event port.
 *
 *  \see rte_event_port_setup(), rte_event_port_link()
 */

/** Event queue configuration structure */
struct rte_event_queue_conf {
	uint32_t nb_atomic_flows;
	/**< The maximum number of active flows this queue can track at any
	 * given time. The value must be in the range of
	 * [1 - max_event_queue_flows)] which previously supplied
	 * to rte_event_dev_configure().
	 */
	uint32_t nb_atomic_order_sequences;
	/**< The maximum number of outstanding events waiting to be (egress-)
	 * reordered by this queue. In other words, the number of entries in
	 * this queue’s reorder buffer.The value must be in the range of
	 * [1 - max_event_queue_flows)] which previously supplied
	 * to rte_event_dev_configure().
	 */
	uint32_t event_queue_cfg; /**< Queue config flags(EVENT_QUEUE_CFG_) */
	uint8_t priority;
	/**< Priority for this event queue relative to other event queues.
	 * The requested priority should in the range of
	 * [RTE_EVENT_QUEUE_PRIORITY_HIGHEST, RTE_EVENT_QUEUE_PRIORITY_LOWEST].
	 * The implementation shall normalize the requested priority to
	 * event device supported priority value.
	 * Valid when the device has RTE_EVENT_DEV_CAP_QUEUE_QOS capability
	 */
};

/**
 * Retrieve the default configuration information of an event queue designated
 * by its *queue_id* from the event driver for an event device.
 *
 * This function intended to be used in conjunction with rte_event_queue_setup()
 * where caller needs to set up the queue by overriding few default values.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param queue_id
 *   The index of the event queue to get the configuration information.
 *   The value must be in the range [0, nb_event_queues - 1]
 *   previously supplied to rte_event_dev_configure().
 * @param[out] queue_conf
 *   The pointer to the default event queue configuration data.
 *
 * \see rte_event_queue_setup()
 *
 */
extern void
rte_event_queue_default_conf_get(uint8_t dev_id, uint8_t queue_id,
				 struct rte_event_queue_conf *queue_conf);

/**
 * Allocate and set up an event queue for an event device.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param queue_id
 *   The index of the event queue to setup. The value must be in the range
 *   [0, nb_event_queues - 1] previously supplied to rte_event_dev_configure().
 * @param queue_conf
 *   The pointer to the configuration data to be used for the event queue.
 *   NULL value is allowed, in which case default configuration	used.
 *
 * \see rte_event_queue_default_conf_get()
 *
 * @return
 *   - 0: Success, event queue correctly set up.
 *   - <0: event queue configuration failed
 */
extern int
rte_event_queue_setup(uint8_t dev_id, uint8_t queue_id,
		      struct rte_event_queue_conf *queue_conf);

/**
 * Get the number of event queues on a specific event device
 *
 * @param dev_id
 *   Event device identifier.
 * @return
 *   - The number of configured event queues
 */
extern uint16_t
rte_event_queue_count(uint8_t dev_id);

/**
 * Get the priority of the event queue on a specific event device
 *
 * @param dev_id
 *   Event device identifier.
 * @param queue_id
 *   Event queue identifier.
 * @return
 *   - If the device has RTE_EVENT_DEV_CAP_QUEUE_QOS capability then the
 *    configured priority of the event queue in
 *    [RTE_EVENT_QUEUE_PRIORITY_HIGHEST, RTE_EVENT_QUEUE_PRIORITY_LOWEST] range
 *    else the value one
 */
extern uint8_t
rte_event_queue_priority(uint8_t dev_id, uint8_t queue_id);

/* Event port specific APIs */

/** Event port configuration structure */
struct rte_event_port_conf {
	int32_t new_event_threshold;
	/**< A backpressure threshold for new event enqueues on this port.
	 * Use for *closed system* event dev where event capacity is limited,
	 * and cannot exceed the capacity of the event dev.
	 * Configuring ports with different thresholds can make higher priority
	 * traffic less likely to  be backpressured.
	 * For example, a port used to inject NIC Rx packets into the event dev
	 * can have a lower threshold so as not to overwhelm the device,
	 * while ports used for worker pools can have a higher threshold.
	 */
	uint8_t dequeue_queue_depth;
	/**< Configure number of bulk dequeues for this event port.
	 * This value cannot exceed the *max_event_port_dequeue_queue_depth*
	 * which previously supplied to rte_event_dev_configure()
	 */
	uint8_t enqueue_queue_depth;
	/**< Configure number of bulk enqueues for this event port.
	 * This value cannot exceed the *max_event_port_enqueue_queue_depth*
	 * which previously supplied to rte_event_dev_configure()
	 */
};

/**
 * Retrieve the default configuration information of an event port designated
 * by its *port_id* from the event driver for an event device.
 *
 * This function intended to be used in conjunction with rte_event_port_setup()
 * where caller needs to set up the port by overriding few default values.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The index of the event port to get the configuration information.
 *   The value must be in the range [0, nb_event_ports - 1]
 *   previously supplied to rte_event_dev_configure().
 * @param[out] port_conf
 *   The pointer to the default event port configuration data
 *
 * \see rte_event_port_setup()
 *
 */
extern void
rte_event_port_default_conf_get(uint8_t dev_id, uint8_t port_id,
				struct rte_event_port_conf *port_conf);

/**
 * Allocate and set up an event port for an event device.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The index of the event port to setup. The value must be in the range
 *   [0, nb_event_ports - 1] previously supplied to rte_event_dev_configure().
 * @param port_conf
 *   The pointer to the configuration data to be used for the queue.
 *   NULL value is allowed, in which case default configuration	used.
 *
 * \see rte_event_port_default_conf_get()
 *
 * @return
 *   - 0: Success, event port correctly set up.
 *   - <0: Port configuration failed
 *   - (-EDQUOT) Quota exceeded(Application tried to link the queue configured
 *   with RTE_EVENT_QUEUE_CFG_SINGLE_CONSUMER to more than one event ports)
 */
extern int
rte_event_port_setup(uint8_t dev_id, uint8_t port_id,
		     struct rte_event_port_conf *port_conf);

/**
 * Get the number of dequeue queue depth configured for event port designated
 * by its *port_id* on a specific event device
 *
 * @param dev_id
 *   Event device identifier.
 * @param port_id
 *   Event port identifier.
 * @return
 *   - The number of configured dequeue queue depth
 *
 * \see rte_event_dequeue_burst()
 */
extern uint8_t
rte_event_port_dequeue_depth(uint8_t dev_id, uint8_t port_id);

/**
 * Get the number of enqueue queue depth configured for event port designated
 * by its *port_id* on a specific event device
 *
 * @param dev_id
 *   Event device identifier.
 * @param port_id
 *   Event port identifier.
 * @return
 *   - The number of configured enqueue queue depth
 *
 * \see rte_event_enqueue_burst()
 */
extern uint8_t
rte_event_port_enqueue_depth(uint8_t dev_id, uint8_t port_id);

/**
 * Get the number of ports on a specific event device
 *
 * @param dev_id
 *   Event device identifier.
 * @return
 *   - The number of configured ports
 */
extern uint8_t
rte_event_port_count(uint8_t dev_id);

/**
 * Start an event device.
 *
 * The device start step is the last one and consists of setting the event
 * queues to start accepting the events and schedules to event ports.
 *
 * On success, all basic functions exported by the API (event enqueue,
 * event dequeue and so on) can be invoked.
 *
 * @param dev_id
 *   Event device identifier
 * @return
 *   - 0: Success, device started.
 *   - <0: Error code of the driver device start function.
 */
extern int
rte_event_dev_start(uint8_t dev_id);

/**
 * Stop an event device. The device can be restarted with a call to
 * rte_event_dev_start()
 *
 * @param dev_id
 *   Event device identifier.
 */
extern void
rte_event_dev_stop(uint8_t dev_id);

/**
 * Close an event device. The device cannot be restarted!
 *
 * @param dev_id
 *   Event device identifier
 *
 * @return
 *  - 0 on successfully closing device
 *  - <0 on failure to close device
 */
extern int
rte_event_dev_close(uint8_t dev_id);

/* Scheduler type definitions */
#define RTE_SCHED_TYPE_ORDERED		0
/**< Ordered scheduling
 *
 * Events from an ordered flow of an event queue can be scheduled to multiple
 * ports for concurrent processing while maintaining the original event order.
 * This scheme enables the user to achieve high single flow throughput by
 * avoiding SW synchronization for ordering between ports which bound to cores.
 *
 * The source flow ordering from an event queue is maintained when events are
 * enqueued to their destination queue within the same ordered flow context.
 * An event port holds the context until application call rte_event_dequeue()
 * from the same port, which implicitly releases the context.
 * User may allow the scheduler to release the context earlier than that
 * by calling rte_event_release()
 *
 * Events from the source queue appear in their original order when dequeued
 * from a destination queue.
 * Event ordering is based on the received event(s), but also other
 * (newly allocated or stored) events are ordered when enqueued within the same
 * ordered context. Events not enqueued (e.g. released or stored) within the
 * context are  considered missing from reordering and are skipped at this time
 * (but can be ordered again within another context).
 *
 * \see rte_event_dequeue(), rte_event_release()
 */

#define RTE_SCHED_TYPE_ATOMIC		1
/**< Atomic scheduling
 *
 * Events from an atomic flow of an event queue can be scheduled only to a
 * single port at a time. The port is guaranteed to have exclusive (atomic)
 * access to the associated flow context, which enables the user to avoid SW
 * synchronization. Atomic flows also help to maintain event ordering
 * since only one port at a time can process events from a flow of an
 * event queue.
 *
 * The atomic queue synchronization context is dedicated to the port until
 * application call rte_event_dequeue() from the same port, which implicitly
 * releases the context. User may allow the scheduler to release the context
 * earlier than that by calling rte_event_release()
 *
 * \see rte_event_dequeue(), rte_event_release()
 */

#define RTE_SCHED_TYPE_PARALLEL		2
/**< Parallel scheduling
 *
 * The scheduler performs priority scheduling, load balancing, etc. functions
 * but does not provide additional event synchronization or ordering.
 * It is free to schedule events from a single parallel flow of an event queue
 * to multiple events ports for concurrent processing.
 * The application is responsible for flow context synchronization and
 * event ordering (SW synchronization).
 */

/* Event types to classify the event source */
#define RTE_EVENT_TYPE_ETHDEV		0x0
/**< The event generated from ethdev subsystem */
#define RTE_EVENT_TYPE_CRYPTODEV	0x1
/**< The event generated from crypodev subsystem */
#define RTE_EVENT_TYPE_TIMERDEV		0x2
/**< The event generated from timerdev subsystem */
#define RTE_EVENT_TYPE_CORE		0x3
/**< The event generated from core.
 * Application may use *sub_event_type* to further classify the event
 */
#define RTE_EVENT_TYPE_MAX		0x10
/**< Maximum number of event types */

/* Event priority */
#define RTE_EVENT_PRIORITY_HIGHEST      0
/**< Highest event priority */
#define RTE_EVENT_PRIORITY_NORMAL       128
/**< Normal event priority */
#define RTE_EVENT_PRIORITY_LOWEST       255
/**< Lowest event priority */

/**
 * The generic *rte_event* structure to hold the event attributes
 * for dequeue and enqueue operation
 */
struct rte_event {
	/** WORD0 */
	RTE_STD_C11
        union {
		uint64_t u64;
		/** Event attributes for dequeue or enqueue operation */
		struct {
			uint32_t flow_id:24;
			/**< Targeted flow identifier for the enqueue and
			 * dequeue operation.
			 * The value must be in the range of
			 * [1 - max_event_queue_flows)] which
			 * previously supplied to rte_event_dev_configure().
			 */
			uint32_t queue_id:8;
			/**< Targeted event queue identifier for the enqueue or
			 * dequeue operation.
			 * The value must be in the range of
			 * [0, nb_event_queues - 1] which previously supplied to
			 * rte_event_dev_configure().
			 */
			uint8_t  sched_type;
			/**< Scheduler synchronization type (RTE_SCHED_TYPE_)
			 * associated with flow id on a given event queue
			 * for the enqueue and dequeue operation.
			 */
			uint8_t  event_type;
			/**< Event type to classify the event source. */
			uint8_t  sub_event_type;
			/**< Sub-event types based on the event source.
			 * \see RTE_EVENT_TYPE_CORE
			 */
			uint8_t  priority;
			/**< Event priority relative to other events in the
			 * event queue. The requested priority should in the
			 * range of  [RTE_EVENT_PRIORITY_HIGHEST,
			 * RTE_EVENT_PRIORITY_LOWEST].
			 * The implementation shall normalize the requested
			 * priority to supported priority value.
			 * Valid when the device has RTE_EVENT_DEV_CAP_EVENT_QOS
			 * capability.
			 */
		};
	};
	/** WORD1 */
	RTE_STD_C11
	union {
		uintptr_t event;
		/**< Opaque event pointer */
		struct rte_mbuf *mbuf;
		/**< mbuf pointer if dequeued event is associated with mbuf */
	};
};

/**
 * Schedule one or more events in the event dev.
 *
 * An event dev implementation may define this is a NOOP, for instance if
 * the event dev performs its scheduling in hardware.
 *
 * @param dev_id
 *   The identifier of the device.
 */
extern void
rte_event_schedule(uint8_t dev_id);

/**
 * Enqueue the event object supplied in the *rte_event* structure on an
 * event device designated by its *dev_id* through the event port specified by
 * *port_id*. The event object specifies the event queue on which this
 * event will be enqueued.
 *
 * @param dev_id
 *   Event device identifier.
 * @param port_id
 *   The identifier of the event port.
 * @param ev
 *   Pointer to struct rte_event
 * @param pin_event
 *   Hint to the scheduler that the event can be pinned to the same port for
 *   the next scheduling stage. For implementations that support it, this
 *   allows the same core to process the next stage in the pipeline for a given
 *   event, taking advantage of cache locality. The pinned event will be
 *   received through rte_event_dequeue(). This is a hint and the event is
 *   not guaranteed to be pinned to the port. This hint is valid only when the
 *   event is dequeued with rte_event_dequeue() followed by rte_event_enqueue().
 *
 * @return
 *  - 0 on success
 *  - <0 on failure. Failure can occur if the event port's output queue is
 *     backpressured, for instance.
 */
extern int
rte_event_enqueue(uint8_t dev_id, uint8_t port_id, struct rte_event *ev,
		  bool pin_event);

/**
 * Enqueue a burst of events objects supplied in *rte_event* structure on an
 * event device designated by its *dev_id* through the event port specified by
 * *port_id*. Each event object specifies the event queue on which it
 * will be enqueued.
 *
 * The rte_event_enqueue_burst() function is invoked to enqueue
 * multiple event objects.
 * It is the burst variant of rte_event_enqueue() function.
 *
 * The *num* parameter is the number of event objects to enqueue which are
 * supplied in the *ev* array of *rte_event* structure.
 *
 * The rte_event_enqueue_burst() function returns the number of
 * events objects it actually enqueued. A return value equal to *num* means
 * that all event objects have been enqueued.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The identifier of the event port.
 * @param ev
 *   An array of *num* pointers to *rte_event* structure
 *   which contain the event object enqueue operations to be processed.
 * @param num
 *   The number of event objects to enqueue, typically number of
 *   rte_event_port_enqueue_depth() available for this port.
 * @param pin_event
 *   Hint to the scheduler that the event can be pinned to the same port for
 *   the next scheduling stage. For implementations that support it, this
 *   allows the same core to process the next stage in the pipeline for a given
 *   event, taking advantage of cache locality. The pinned event will be
 *   received through rte_event_dequeue(). This is a hint and the event is
 *   not guaranteed to be pinned to the port. This hint is valid only when the
 *   event is dequeued with rte_event_dequeue() followed by rte_event_enqueue().
 *
 * @return
 *   The number of event objects actually enqueued on the event device. The
 *   return value can be less than the value of the *num* parameter when the
 *   event devices queue is full or if invalid parameters are specified in a
 *   *rte_event*. If return value is less than *num*, the remaining events at
 *   the end of ev[] are not consumed, and the caller has to take care of them.
 *
 * \see rte_event_enqueue(), rte_event_port_enqueue_depth()
 */
extern int
rte_event_enqueue_burst(uint8_t dev_id, uint8_t port_id,
			struct rte_event ev[], int num, bool pin_event);

/**
 * Converts nanoseconds to *wait* value for rte_event_dequeue()
 *
 * If the device is configured with RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT flag then
 * application can use this function to convert wait value in nanoseconds to
 * implementations specific wait value supplied in rte_event_dequeue()
 *
 * @param dev_id
 *   The identifier of the device.
 * @param ns
 *   Wait time in nanosecond
 *
 * @return
 * Value for the *wait* parameter in rte_event_dequeue() function
 *
 * \see rte_event_dequeue(), RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT
 * \see rte_event_dev_configure()
 *
 */
extern uint64_t
rte_event_dequeue_wait_time(uint8_t dev_id, uint64_t ns);

/**
 * Dequeue an event from the event port specified by *port_id* on the
 * event device designated by its *dev_id*.
 *
 * rte_event_dequeue() does not dictate the specifics of scheduling algorithm as
 * each eventdev driver may have different criteria to schedule an event.
 * However, in general, from an application perspective scheduler may use the
 * following scheme to dispatch an event to the port.
 *
 * 1) Selection of event queue based on
 *   a) The list of event queues are linked to the event port.
 *   b) If the device has RTE_EVENT_DEV_CAP_QUEUE_QOS capability then event
 *   queue selection from list is based on event queue priority relative to
 *   other event queue supplied as *priority* in rte_event_queue_setup()
 *   c) If the device has RTE_EVENT_DEV_CAP_EVENT_QOS capability then event
 *   queue selection from the list is based on event priority supplied as
 *   *priority* in rte_event_enqueue_burst()
 * 2) Selection of event
 *   a) The number of flows available in selected event queue.
 *   b) Schedule type method associated with the event
 *
 * On a successful dequeue, the event port holds flow id and schedule type
 * context associated with the dispatched event. The context is automatically
 * released in the next rte_event_dequeue() invocation, or rte_event_release()
 * can be called to release the context early.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The identifier of the event port.
 * @param[out] ev
 *   Pointer to struct rte_event. On successful event dispatch, implementation
 *   updates the event attributes.
 * @param wait
 *   0 - no-wait, returns immediately if there is no event.
 *   >0 - wait for the event, if the device is configured with
 *   RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT then this function will wait until
 *   the event available or *wait* time.
 *   if the device is not configured with RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT
 *   then this function will wait until the event available or *dequeue_wait_ns*
 *   ns which was previously supplied to rte_event_dev_configure()
 *
 * @return
 * When true, a valid event has been dispatched by the scheduler.
 *
 */
extern bool
rte_event_dequeue(uint8_t dev_id, uint8_t port_id,
		  struct rte_event *ev, uint64_t wait);

/**
 * Dequeue a burst of events objects from the event port designated by its
 * *event_port_id*, on an event device designated by its *dev_id*.
 *
 * The rte_event_dequeue_burst() function is invoked to dequeue
 * multiple event objects. It is the burst variant of rte_event_dequeue()
 * function.
 *
 * The *num* parameter is the maximum number of event objects to dequeue which
 * are returned in the *ev* array of *rte_event* structure.
 *
 * The rte_event_dequeue_burst() function returns the number of
 * events objects it actually dequeued. A return value equal to
 * *num* means that all event objects have been dequeued.
 *
 * The number of events dequeued is the number of scheduler contexts held by
 * this port. These contexts are automatically released in the next
 * rte_event_dequeue() invocation, or rte_event_release() can be called once
 * per event to release the contexts early.
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The identifier of the event port.
 * @param[out] ev
 *   An array of *num* pointers to *rte_event* structure which is populated
 *   with the dequeued event objects.
 * @param num
 *   The maximum number of event objects to dequeue, typically number of
 *   rte_event_port_dequeue_depth() available for this port.
 * @param wait
 *   0 - no-wait, returns immediately if there is no event.
 *   >0 - wait for the event, if the device is configured with
 *   RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT then this function will wait until the
 *   event available or *wait* time.
 *   if the device is not configured with RTE_EVENT_DEV_CFG_PER_DEQUEUE_WAIT
 *   then this function will wait until the event available or *dequeue_wait_ns*
 *   ns which was previously supplied to rte_event_dev_configure()
 *
 * @return
 * The number of event objects actually dequeued from the port. The return
 * value can be less than the value of the *num* parameter when the
 * event port's queue is not full.
 *
 * \see rte_event_dequeue(), rte_event_port_dequeue_depth()
 */
extern int
rte_event_dequeue_burst(uint8_t dev_id, uint8_t port_id,
			struct rte_event *ev, int num, uint64_t wait);

/**
 * Release the current flow context associated with a schedule type which
 * dequeued from a given event queue though the event port designated by
 * its *port_id*
 *
 * If current flow's scheduler type method is *RTE_SCHED_TYPE_ATOMIC*
 * then this function hints the scheduler that the user has completed critical
 * section processing in the current atomic context.
 * The scheduler is now allowed to schedule events from the same flow from
 * an event queue to another port. However, the context may be still held
 * until the next rte_event_dequeue() or rte_event_dequeue_burst() call, this
 * call allows but does not force the scheduler to release the context early.
 *
 * Early atomic context release may increase parallelism and thus system
 * performance, but the user needs to design carefully the split into critical
 * vs non-critical sections.
 *
 * If current flow's scheduler type method is *RTE_SCHED_TYPE_ORDERED*
 * then this function hints the scheduler that the user has done all that need
 * to maintain event order in the current ordered context.
 * The scheduler is allowed to release the ordered context of this port and
 * avoid reordering any following enqueues.
 *
 * Early ordered context release may increase parallelism and thus system
 * performance.
 *
 * If current flow's scheduler type method is *RTE_SCHED_TYPE_PARALLEL*
 * or no scheduling context is held then this function may be an NOOP,
 * depending on the implementation.
 *
 * If multiple events are dequeued with rte_event_dequeue_burst(),
 * rte_event_release() will release each flow context associated with a
 * schedule type of an event though *index*, it denotes the order in
 * which it was dequeued with rte_event_dequeue_burst()
 *
 * @param dev_id
 *   The identifier of the device.
 * @param port_id
 *   The identifier of the event port.
 * @param index
 *   The index of the event that dequeued with rte_event_dequeue_burst()
 *   which needs to release. The value zero used if the event dequeued with
 *   rte_event_dequeue()
 *
 *  \see rte_event_dequeue(), rte_event_dequeue_burst()
 */
extern void
rte_event_release(uint8_t dev_id, uint8_t port_id, uint8_t index);

#define RTE_EVENT_QUEUE_SERVICE_PRIORITY_HIGHEST  0
/**< Highest event queue servicing priority */
#define RTE_EVENT_QUEUE_SERVICE_PRIORITY_NORMAL   128
/**< Normal event queue servicing priority */
#define RTE_EVENT_QUEUE_SERVICE_PRIORITY_LOWEST   255
/**< Lowest event queue servicing priority */

/** Structure to hold the queue to port link establishment attributes */
struct rte_event_queue_link {
	uint8_t queue_id;
	/**< Event queue identifier to select the source queue to link */
	uint8_t priority;
	/**< The priority of the event queue for this event port.
	 * The priority defines the event port's servicing priority for
	 * event queue, which may be ignored by an implementation.
	 * The requested priority should in the range of
	 * [RTE_EVENT_QUEUE_SERVICE_PRIORITY_HIGHEST,
	 * RTE_EVENT_QUEUE_SERVICE_PRIORITY_LOWEST].
	 * The implementation shall normalize the requested priority to
	 * implementation supported priority value.
	 */
};

/**
 * Link multiple source event queues supplied in *rte_event_queue_link*
 * structure as *queue_id* to the destination event port designated by its
 * *port_id* on the event device designated by its *dev_id*.
 *
 * The link establishment shall enable the event port *port_id* from
 * receiving events from the specified event queue *queue_id*
 *
 * An event queue may link to one or more event ports.
 * The number of links can be established from an event queue to event port is
 * implementation defined.
 *
 * Event queue(s) to event port link establishment can be changed at runtime
 * without re-configuring the device to support scaling and to reduce the
 * latency of critical work by establishing the link with more event ports
 * at runtime.
 *
 * @param dev_id
 *   The identifier of the device.
 *
 * @param port_id
 *   Event port identifier to select the destination port to link.
 *
 * @param link
 *   An array of *num* pointers to *rte_event_queue_link* structure
 *   which contain the event queue to event port link establishment attributes.
 *   NULL value is allowed, in which case this function links all the configured
 *   event queues *nb_event_queues* which previously supplied to
 *   rte_event_dev_configure() to the event port *port_id* with normal servicing
 *   priority(RTE_EVENT_QUEUE_SERVICE_PRIORITY_NORMAL).
 *
 * @param num
 *   The number of links to establish
 *
 * @return
 * The number of links actually established on the event device. The return
 * value can be less than the value of the *num* parameter when the
 * implementation has the limitation on specific queue to port link
 * establishment or if invalid parameters are specified
 * in a *rte_event_queue_link*.
 * If the return value is less than *num*, the remaining links at the end of
 * link[] are not established, and the caller has to take care of them.
 * If return value is less than *num* then implementation shall update the
 * rte_errno accordingly, Possible rte_errno values are
 * (-EDQUOT) Quota exceeded(Application tried to link the queue configured with
 *  RTE_EVENT_QUEUE_CFG_SINGLE_CONSUMER to more than one event ports)
 * (-EINVAL) Invalid parameter
 *
 */
extern int
rte_event_port_link(uint8_t dev_id, uint8_t port_id,
		    struct rte_event_queue_link link[], int num);

/**
 * Unlink multiple source event queues supplied in *queues* from the destination
 * event port designated by its *port_id* on the event device designated
 * by its *dev_id*.
 *
 * The unlink establishment shall disable the event port *port_id* from
 * receiving events from the specified event queue *queue_id*
 *
 * Event queue(s) to event port unlink establishment can be changed at runtime
 * without re-configuring the device.
 *
 * @param dev_id
 *   The identifier of the device.
 *
 * @param port_id
 *   Event port identifier to select the destination port to unlink.
 *
 * @param queues
 *   An array of *num* event queues to be unlinked from the event port.
 *   NULL value is allowed, in which case this function unlinks all the
 *   event queue(s) from the event port *port_id*.
 *
 * @param num
 *   The number of unlinks to establish
 *
 * @return
 * The number of unlinks actually established on the event device. The return
 * value can be less than the value of the *num* parameter when the
 * implementation has the limitation on specific queue to port unlink
 * establishment or if invalid parameters are specified.
 * If the return value is less than *num*, the remaining queues at the end of
 * queues[] are not established, and the caller has to take care of them.
 * If return value is less than *num* then implementation shall update the
 * rte_errno accordingly, Possible rte_errno values are
 * (-EINVAL) Invalid parameter
 *
 */
extern int
rte_event_port_unlink(uint8_t dev_id, uint8_t port_id,
		    uint8_t queues[], int num);

#ifdef __cplusplus
}
#endif

#endif /* _RTE_EVENTDEV_H_ */