mctp_i2c_gpio_controller.h

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/*
 * Copyright (c) 2025 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */
 
#ifndef ZEPHYR_MCTP_I2C_GPIO_CONTROLLER_H_
#define ZEPHYR_MCTP_I2C_GPIO_CONTROLLER_H_
 
#include <stdint.h>
#include <zephyr/kernel.h>
#include <zephyr/device.h>
#include <zephyr/drivers/i2c.h>
#include <zephyr/drivers/gpio.h>
#include <zephyr/sys/mpsc_lockfree.h>
#include <zephyr/rtio/rtio.h>
#include <zephyr/pmci/mctp/mctp_i2c_gpio_common.h>
 
#include <libmctp.h>
#include <stdatomic.h>

 
struct mctp_binding_i2c_gpio_controller;
 
struct mctp_i2c_gpio_controller_cb {
        struct mpsc_node q;
        struct gpio_callback callback;
        struct mctp_binding_i2c_gpio_controller *binding;
        uint8_t index;
};


struct mctp_binding_i2c_gpio_controller {
        struct mctp_binding binding;
        const struct device *i2c;
 
        uint8_t rx_buf_len;
        uint8_t rx_buf[MCTP_I2C_GPIO_MAX_PKT_SIZE];
        uint8_t tx_buf[MCTP_I2C_GPIO_MAX_PKT_SIZE];
 
        struct mctp_pktbuf *rx_pkt;
 
        /* Avoid needing a thread or work queue task by using RTIO */
        struct k_sem *tx_lock;
        struct rtio *r_tx;
 
        /* Mapping of endpoints to i2c targets with gpios */
        size_t num_endpoints;
        const uint8_t *endpoint_ids;
        const struct rtio_iodev **endpoint_iodevs;
        const struct gpio_dt_spec *endpoint_gpios;
        struct mctp_i2c_gpio_controller_cb *endpoint_gpio_cbs;
 
        /* Ongoing request from a particular gpio */
        struct k_spinlock rx_lock;
        struct rtio *r_rx;
        struct mpsc rx_q;
        struct mctp_i2c_gpio_controller_cb *inflight_rx;
 
        uint8_t tx_storage[MCTP_PKTBUF_SIZE(MCTP_I2C_GPIO_MAX_PKT_SIZE)] PKTBUF_STORAGE_ALIGN;

};

int mctp_i2c_gpio_controller_start(struct mctp_binding *binding);
int mctp_i2c_gpio_controller_tx(struct mctp_binding *binding, struct mctp_pktbuf *pkt);
 
#define MCTP_I2C_GPIO_CONTROLLER_IODEV_NAME(_idx, _name) _name##_idx
 
#define MCTP_I2C_GPIO_CONTROLLER_IODEV_DEFINE(_node_id, addrs, _idx, _name)                        \
        I2C_IODEV_DEFINE(MCTP_I2C_GPIO_CONTROLLER_IODEV_NAME(_idx, _name),                         \
                DT_PHANDLE(_node_id, i2c),                                                         \
                DT_PROP_BY_IDX(_node_id, addrs, _idx));
 
 
#define MCTP_I2C_GPIO_CONTROLLER_DEFINE_GPIOS(_node_id, _name)                                     \
        const struct gpio_dt_spec _name##_endpoint_gpios[] = {                                     \
                DT_FOREACH_PROP_ELEM_SEP(_node_id, endpoint_gpios, GPIO_DT_SPEC_GET_BY_IDX, (,))   \
        }
 
#define MCTP_I2C_GPIO_CONTROLLER_DEFINE_IDS(_node_id, _name)                                       \
        const uint8_t _name##_endpoint_ids[] = DT_PROP(_node_id, endpoint_ids);
 
#define MCTP_I2C_GPIO_CONTROLLER_DEFINE_GPIO_CBS(_node_id, _name)                                  \
        struct mctp_i2c_gpio_controller_cb \
                _name##_endpoint_gpio_cbs[DT_PROP_LEN(_node_id, endpoint_ids)]
 
 
#define MCTP_I2C_GPIO_CONTROLLER_DEFINE_IODEVS(_node_id, _name)                                    \
        DT_FOREACH_PROP_ELEM_VARGS(_node_id, endpoint_addrs,                                       \
                        MCTP_I2C_GPIO_CONTROLLER_IODEV_DEFINE, _name)                              \
                const struct rtio_iodev *_name##_endpoint_iodevs[] = {                             \
                LISTIFY(DT_PROP_LEN(_node_id, endpoint_ids), &MCTP_I2C_GPIO_CONTROLLER_IODEV_NAME, \
                                (,), _name)                                                        \
        }


#define MCTP_I2C_GPIO_CONTROLLER_DT_DEFINE(_name, _node_id)                                        \
        RTIO_DEFINE(_name##_rtio_tx, 5, 5);                                                        \
        RTIO_DEFINE(_name##_rtio_rx, 5, 5);                                                        \
        MCTP_I2C_GPIO_CONTROLLER_DEFINE_IODEVS(_node_id, _name);                                   \
        MCTP_I2C_GPIO_CONTROLLER_DEFINE_GPIOS(_node_id, _name);                                    \
        MCTP_I2C_GPIO_CONTROLLER_DEFINE_IDS(_node_id, _name);                                      \
        MCTP_I2C_GPIO_CONTROLLER_DEFINE_GPIO_CBS(_node_id, _name);                                 \
        K_SEM_DEFINE(_name##_tx_lock, 1, 1);                                                       \
        struct mctp_binding_i2c_gpio_controller _name = {                                          \
                .binding = {                                                                       \
                        .name = STRINGIFY(_name), .version = 1,                                    \
                        .start = mctp_i2c_gpio_controller_start,                                   \
                        .tx = mctp_i2c_gpio_controller_tx,                                         \
                        .pkt_size = MCTP_I2C_GPIO_MAX_PKT_SIZE,                                    \
                        .tx_storage = _name.tx_storage,                                            \
                },                                                                                 \
                .i2c = DEVICE_DT_GET(DT_PHANDLE(_node_id, i2c)),                                   \
                .num_endpoints = DT_PROP_LEN(_node_id, endpoint_ids),                              \
                .endpoint_ids = _name##_endpoint_ids,                                              \
                .endpoint_gpios = _name##_endpoint_gpios,                                          \
                .endpoint_gpio_cbs = _name##_endpoint_gpio_cbs,                                    \
                .endpoint_iodevs = _name##_endpoint_iodevs,                                        \
                .r_tx = &_name##_rtio_tx,                                                          \
                .r_rx = &_name##_rtio_rx,                                                          \
                .tx_lock = &_name##_tx_lock,                                                       \
        };
 
#endif /* ZEPHYR_MCTP_I2C_GPIO_CONTROLLER_H_ */