io_storage.h

/*
 * Copyright (c) 2014, ARM Limited and Contributors. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of ARM nor the names of its contributors may be used
 * to endorse or promote products derived from this software without specific
 * prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef __IO_H__
#define __IO_H__

#include <errno.h>
#include <stdint.h>
#include <stdio.h> /* For ssize_t */
#include <uuid.h>


/* Device type which can be used to enable policy decisions about which device
 * to access */
typedef enum {
	IO_TYPE_INVALID,
	IO_TYPE_SEMIHOSTING,
	IO_TYPE_MEMMAP,
	IO_TYPE_FIRMWARE_IMAGE_PACKAGE,
	IO_TYPE_MAX
} io_type_t;


/* Modes used when seeking data on a supported device */
typedef enum {
	IO_SEEK_INVALID,
	IO_SEEK_SET,
	IO_SEEK_END,
	IO_SEEK_CUR,
	IO_SEEK_MAX
} io_seek_mode_t;


/* Connector type, providing a means of identifying a device to open */
struct io_dev_connector;


/* File specification - used to refer to data on a device supporting file-like
 * entities */
typedef struct io_file_spec {
	const char *path;
	unsigned int mode;
} io_file_spec_t;

/* UUID specification - used to refer to data accessed using UUIDs (i.e. FIP
 * images) */
typedef struct io_uuid_spec {
	const uuid_t uuid;
} io_uuid_spec_t;

/* Block specification - used to refer to data on a device supporting
 * block-like entities */
typedef struct io_block_spec {
	size_t offset;
	size_t length;
} io_block_spec_t;


/* Access modes used when accessing data on a device */
#define IO_MODE_INVALID (0)
#define IO_MODE_RO	(1 << 0)
#define IO_MODE_RW	(1 << 1)


/* Return codes reported by 'io_*' APIs.
 * IMPORTANT: these definitions are deprecated. Callers should use standard
 * errno definitions when checking the return value of io_* APIs. */
#define IO_SUCCESS		(0)
#define IO_FAIL			(-ENOENT)
#define IO_NOT_SUPPORTED	(-ENODEV)
#define IO_RESOURCES_EXHAUSTED	(-ENOMEM)


/* Open a connection to a device */
int io_dev_open(const struct io_dev_connector *dev_con,
		const uintptr_t dev_spec,
		uintptr_t *dev_handle);


/* Initialise a device explicitly - to permit lazy initialisation or
 * re-initialisation */
int io_dev_init(uintptr_t dev_handle, const uintptr_t init_params);

/* TODO: Consider whether an explicit "shutdown" API should be included */

/* Close a connection to a device */
int io_dev_close(uintptr_t dev_handle);


/* Synchronous operations */
int io_open(uintptr_t dev_handle, const uintptr_t spec, uintptr_t *handle);

int io_seek(uintptr_t handle, io_seek_mode_t mode, ssize_t offset);

int io_size(uintptr_t handle, size_t *length);

int io_read(uintptr_t handle, uintptr_t buffer, size_t length,
		size_t *length_read);

int io_write(uintptr_t handle, const uintptr_t buffer, size_t length,
		size_t *length_written);

int io_close(uintptr_t handle);


#endif /* __IO_H__ */