linux/drivers/net/mctp/mctp-serial.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Management Component Transport Protocol (MCTP) - serial transport
 * binding. This driver is an implementation of the DMTF specificiation
 * "DSP0253 - Management Component Transport Protocol (MCTP) Serial Transport
 * Binding", available at:
 *
 *  https://www.dmtf.org/sites/default/files/standards/documents/DSP0253_1.0.0.pdf
 *
 * This driver provides DSP0253-type MCTP-over-serial transport using a Linux
 * tty device, by setting the N_MCTP line discipline on the tty.
 *
 * Copyright (c) 2021 Code Construct
 */

#include <linux/idr.h>
#include <linux/if_arp.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/tty.h>
#include <linux/workqueue.h>
#include <linux/crc-ccitt.h>

#include <linux/mctp.h>
#include <net/mctp.h>
#include <net/pkt_sched.h>

#define MCTP_SERIAL_MTU …
#define MCTP_SERIAL_FRAME_MTU …

#define MCTP_SERIAL_VERSION …

#define BUFSIZE …

#define BYTE_FRAME …
#define BYTE_ESC …

#define FCS_INIT …

static DEFINE_IDA(mctp_serial_ida);

enum mctp_serial_state { … };

struct mctp_serial { … };

static bool needs_escape(u8 c)
{ … }

static unsigned int next_chunk_len(struct mctp_serial *dev)
{ … }

static ssize_t write_chunk(struct mctp_serial *dev, u8 *buf, size_t len)
{ … }

static void mctp_serial_tx_work(struct work_struct *work)
{ … }

static netdev_tx_t mctp_serial_tx(struct sk_buff *skb, struct net_device *ndev)
{ … }

static void mctp_serial_tty_write_wakeup(struct tty_struct *tty)
{ … }

static void mctp_serial_rx(struct mctp_serial *dev)
{ … }

static void mctp_serial_push_header(struct mctp_serial *dev, u8 c)
{ … }

static void mctp_serial_push_trailer(struct mctp_serial *dev, u8 c)
{ … }

static void mctp_serial_push(struct mctp_serial *dev, u8 c)
{ … }

static void mctp_serial_tty_receive_buf(struct tty_struct *tty, const u8 *c,
					const u8 *f, size_t len)
{ … }

static void mctp_serial_uninit(struct net_device *ndev)
{ … }

static const struct net_device_ops mctp_serial_netdev_ops = …;

static void mctp_serial_setup(struct net_device *ndev)
{ … }

static int mctp_serial_open(struct tty_struct *tty)
{ … }

static void mctp_serial_close(struct tty_struct *tty)
{ … }

static struct tty_ldisc_ops mctp_ldisc = …;

static int __init mctp_serial_init(void)
{ … }

static void __exit mctp_serial_exit(void)
{ … }

module_init(…) …;
module_exit(mctp_serial_exit);

MODULE_LICENSE(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;

#if IS_ENABLED(CONFIG_MCTP_SERIAL_TEST)
#include <kunit/test.h>

#define MAX_CHUNKS …
struct test_chunk_tx { … };

static void test_next_chunk_len(struct kunit *test)
{ … }

static struct test_chunk_tx chunk_tx_tests[] = …;

KUNIT_ARRAY_PARAM(chunk_tx, chunk_tx_tests, NULL);

static struct kunit_case mctp_serial_test_cases[] = …;

static struct kunit_suite mctp_serial_test_suite = …;

kunit_test_suite(…) …;

#endif /* CONFIG_MCTP_SERIAL_TEST */