/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2025 Oxide Computer Company
 */

#ifndef _EEDEV_H
#define _EEDEV_H

/*
 * A small set of utilities to make reading and writing EEPROM class devices
 * simpler. Right now this mostly just facilitates reading and writing.
 */

#include <sys/types.h>
#include <sys/uio.h>
#include <sys/cred.h>
#include <sys/devops.h>
#include <sys/stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

#define EEDEV_REG_VERS0 0
#define EEDEV_REG_VERS  EEDEV_REG_VERS0

/*
 * The maximum number of characters in a name for a device. Only alphanumeric
 * characters and '_' and '-' are allowed in the name.
 */
#define EEDEV_NAME_MAX  32

typedef struct {
        int (*eo_read)(void *, uio_t *, uint32_t, uint32_t, uint32_t);
        int (*eo_write)(void *, uio_t *, uint32_t, uint32_t, uint32_t);
} eedev_ops_t;

typedef struct {
        uint32_t ereg_vers;
        /*
         * Size of the device in bytes.
         */
        uint32_t ereg_size;
        /*
         * This is the size and alignment of a given page in a device. If this
         * is left as zero, then the device can address all of the data without
         * taking action.
         */
        uint32_t ereg_seg;
        /*
         * This is the access granularity or the number of bytes per address in
         * the device. For example, a 512-byte device with an access granularity
         * of 2, would have 256 2-byte addresses available.
         */
        uint32_t ereg_read_gran;
        uint32_t ereg_write_gran;
        /*
         * This is the maximum number of bytes that can be in a read or write
         * request in one go. A value of zero means the device doesn't care.
         */
        uint32_t ereg_max_read;
        uint32_t ereg_max_write;
        /*
         * Is the device read-only. If this is false, then it is an error to not
         * include a write operation.
         */
        bool ereg_ro;
        uint8_t ereg_rsvd[3];
        /*
         * Identifying information. The dip is what device this belongs to. The
         * name is the name that should be used. If left NULL a default name of
         * "eeprom" will be used. If the driver is going to create more than a
         * single device per dev_info_t, it should fill this in. The minor
         * should be a minor allocated by the driver for use here.
         */
        dev_info_t *ereg_dip;
        void *ereg_driver;
        const char *ereg_name;
        const eedev_ops_t *ereg_ops;
} eedev_reg_t;

typedef struct eedev_hdl eedev_hdl_t;

/*
 * Functions to create and finish an eedev handle.
 */
extern int eedev_create(const eedev_reg_t *, eedev_hdl_t **);
extern void eedev_fini(eedev_hdl_t *);

#ifdef __cplusplus
}
#endif

#endif /* _EEDEV_H */