numam-spdk/include/spdk/ioat.h

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/** \file
 * This file defines the public interface to the I/OAT DMA engine driver.
 */

#ifndef __IOAT_H__
#define __IOAT_H__

#include <inttypes.h>
#include <stdbool.h>
#include "spdk/pci.h"

#include "spdk/pci.h"

/**
 * Opaque handle for a single I/OAT channel returned by \ref ioat_probe().
 */
struct ioat_channel;

/**
 * Signature for callback function invoked when a request is completed.
 */
typedef void (*ioat_callback_t)(void *arg);

/**
 * Callback for ioat_probe() enumeration.
 *
 * \return true to attach to this device.
 */
typedef bool (*ioat_probe_cb)(void *cb_ctx, struct spdk_pci_device *pci_dev);

/**
 * Callback for ioat_probe() to report a device that has been attached to the userspace I/OAT driver.
 */
typedef void (*ioat_attach_cb)(void *cb_ctx, struct spdk_pci_device *pci_dev,
			       struct ioat_channel *ioat);

/**
 * \brief Enumerate the I/OAT devices attached to the system and attach the userspace I/OAT driver
 * to them if desired.
 *
 * \param probe_cb will be called once per I/OAT device found in the system.
 * \param attach_cb will be called for devices for which probe_cb returned true once the I/OAT
 * controller has been attached to the userspace driver.
 *
 * If called more than once, only devices that are not already attached to the SPDK I/OAT driver
 * will be reported.
 *
 * To stop using the the controller and release its associated resources,
 * call \ref ioat_detach with the ioat_channel instance returned by this function.
 */
int ioat_probe(void *cb_ctx, ioat_probe_cb probe_cb, ioat_attach_cb attach_cb);

/**
 * Detaches specified device returned by \ref ioat_probe() from the I/OAT driver.
 */
int ioat_detach(struct ioat_channel *ioat);

/**
 * Request a DMA engine channel for the calling thread.
 *
 * Must be called before submitting any requests from a thread.
 *
 * The \ref ioat_unregister_thread() function can be called to release the channel.
 */
int ioat_register_thread(void);

/**
 * Unregister the current thread's I/OAT channel.
 *
 * This function can be called after \ref ioat_register_thread() to release the thread's
 * DMA engine channel for use by other threads.
 */
void ioat_unregister_thread(void);

/**
 * Submit a DMA engine memory copy request.
 *
 * Before submitting any requests on a thread, the thread must be registered
 * using the \ref ioat_register_thread() function.
 */
int64_t ioat_submit_copy(void *cb_arg, ioat_callback_t cb_fn,
			 void *dst, const void *src, uint64_t nbytes);

/**
 * Submit a DMA engine memory fill request.
 *
 * Before submitting any requests on a thread, the thread must be registered
 * using the \ref ioat_register_thread() function.
 */
int64_t ioat_submit_fill(void *cb_arg, ioat_callback_t cb_fn,
			 void *dst, uint64_t fill_pattern, uint64_t nbytes);

/**
 * Check for completed requests on the current thread.
 *
 * Before submitting any requests on a thread, the thread must be registered
 * using the \ref ioat_register_thread() function.
 *
 * \returns 0 on success or negative if something went wrong.
 */
int ioat_process_events(void);

/**
 * DMA engine capability flags
 */
enum ioat_dma_capability_flags {
	IOAT_ENGINE_COPY_SUPPORTED	= 0x1, /**< The memory copy is supported */
	IOAT_ENGINE_FILL_SUPPORTED	= 0x2, /**< The memory fill is supported */
};

/**
 * Get the DMA engine capabilities.
 *
 * Before submitting any requests on a thread, the thread must be registered
 * using the \ref ioat_register_thread() function.
 */
uint32_t ioat_get_dma_capabilities(void);

#endif