mctp_usb.h

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/*
 * Copyright (c) 2024 Intel Corporation
 * Copyright 2025 NXP
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */
 
#ifndef ZEPHYR_MCTP_USB_H_
#define ZEPHYR_MCTP_USB_H_
 
#include <zephyr/sys/iterable_sections.h>
#include <libmctp.h>
 
/* MCTP class subclass options */
#define USBD_MCTP_SUBCLASS_MANAGEMENT_CONTROLLER   0
#define USBD_MCTP_SUBCLASS_MANAGED_DEVICE_ENDPOINT 0
#define USBD_MCTP_SUBCLASS_HOST_INTERFACE_ENDPOINT 1
 
/* MCTP class protocol options */
#define USBD_MCTP_PROTOCOL_1_X 1
#define USBD_MCTP_PROTOCOL_2_X 2
 
/* Binding-specific defines, internal use */
#define MCTP_USB_HEADER_SIZE       4
#define MCTP_USB_MAX_PACKET_LENGTH 255

struct mctp_binding_usb {
        struct mctp_binding binding;
        struct usbd_class_data *usb_class_data;
        uint8_t tx_buf[MCTP_USB_HEADER_SIZE + MCTP_USB_MAX_PACKET_LENGTH];
        struct k_sem tx_lock;
        struct mctp_pktbuf *rx_pkt;
        uint8_t rx_data_idx;
        enum {
                STATE_WAIT_HDR_DMTF0,
                STATE_WAIT_HDR_DMTF1,
                STATE_WAIT_HDR_RSVD0,
                STATE_WAIT_HDR_LEN,
                STATE_DATA
        } rx_state;
        uint8_t tx_storage[MCTP_PKTBUF_SIZE(MCTP_PACKET_SIZE(MCTP_USB_MAX_PACKET_LENGTH))]
                PKTBUF_STORAGE_ALIGN;
};

struct mctp_usb_class_inst {
        uint8_t subclass;
        uint8_t mctp_protocol;
        struct mctp_binding_usb *mctp_binding;
};

int mctp_usb_start(struct mctp_binding *binding);
int mctp_usb_tx(struct mctp_binding *binding, struct mctp_pktbuf *pkt);

#define MCTP_USB_DEFINE(_name, _subclass, _protocol)                                            \
        struct mctp_binding_usb _name = {                                                       \
                .binding = {                                                                    \
                        .name = STRINGIFY(_name),                                               \
                        .version = 1,                                                           \
                        .pkt_size = MCTP_PACKET_SIZE(MCTP_USB_MAX_PACKET_LENGTH),               \
                        .pkt_header = 0,                                                        \
                        .pkt_trailer = 0,                                                       \
                        .tx_storage = _name.tx_storage,                                         \
                        .start = mctp_usb_start,                                                \
                        .tx = mctp_usb_tx                                                       \
                },                                                                              \
                .usb_class_data = NULL,                                                         \
                .rx_pkt = NULL,                                                                 \
                .rx_data_idx = 0,                                                               \
                .rx_state = STATE_WAIT_HDR_DMTF0                                                \
        };                                                                                      \
                                                                                                \
        const STRUCT_SECTION_ITERABLE(mctp_usb_class_inst, mctp_usb_class_inst_##_name) = {     \
                .subclass = _subclass,                                                          \
                .mctp_protocol = _protocol,                                                     \
                .mctp_binding = &_name,                                                         \
        };
 
#endif /* ZEPHYR_MCTP_USB_H_ */