drivers/net/mctp/mctp-serial.c

Source file repositories/reference/linux-study-clean/drivers/net/mctp/mctp-serial.c

File Facts

System
Linux kernel
Corpus path
drivers/net/mctp/mctp-serial.c
Extension
.c
Size
13608 bytes
Lines
635
Domain
Driver Families
Bucket
drivers/net
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

static const struct net_device_ops mctp_serial_netdev_ops = {
	.ndo_start_xmit = mctp_serial_tx,
	.ndo_uninit = mctp_serial_uninit,
};

static void mctp_serial_setup(struct net_device *ndev)
{
	ndev->type = ARPHRD_MCTP;

	/* we limit at the fixed MTU, which is also the MCTP-standard
	 * baseline MTU, so is also our minimum
	 */
	ndev->mtu = MCTP_SERIAL_MTU;
	ndev->max_mtu = MCTP_SERIAL_MTU;
	ndev->min_mtu = MCTP_SERIAL_MTU;

	ndev->hard_header_len = 0;
	ndev->addr_len = 0;
	ndev->tx_queue_len = DEFAULT_TX_QUEUE_LEN;
	ndev->flags = IFF_NOARP;
	ndev->netdev_ops = &mctp_serial_netdev_ops;
	ndev->needs_free_netdev = true;
}

static int mctp_serial_open(struct tty_struct *tty)
{
	struct mctp_serial *dev;
	struct net_device *ndev;
	char name[32];
	int idx, rc;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	if (!tty->ops->write)
		return -EOPNOTSUPP;

	idx = ida_alloc(&mctp_serial_ida, GFP_KERNEL);
	if (idx < 0)
		return idx;

	snprintf(name, sizeof(name), "mctpserial%d", idx);
	ndev = alloc_netdev(sizeof(*dev), name, NET_NAME_ENUM,
			    mctp_serial_setup);
	if (!ndev) {
		rc = -ENOMEM;
		goto free_ida;
	}

	dev = netdev_priv(ndev);
	dev->idx = idx;
	dev->tty = tty;
	dev->netdev = ndev;
	dev->txstate = STATE_IDLE;
	dev->rxstate = STATE_IDLE;
	spin_lock_init(&dev->lock);
	INIT_WORK(&dev->tx_work, mctp_serial_tx_work);

	rc = mctp_register_netdev(ndev, NULL, MCTP_PHYS_BINDING_SERIAL);
	if (rc)
		goto free_netdev;

	tty->receive_room = 64 * 1024;
	tty->disc_data = dev;

	return 0;

free_netdev:
	free_netdev(ndev);

free_ida:
	ida_free(&mctp_serial_ida, idx);
	return rc;
}

static void mctp_serial_close(struct tty_struct *tty)
{
	struct mctp_serial *dev = tty->disc_data;
	int idx = dev->idx;

	mctp_unregister_netdev(dev->netdev);
	ida_free(&mctp_serial_ida, idx);
}

static struct tty_ldisc_ops mctp_ldisc = {
	.owner		= THIS_MODULE,
	.num		= N_MCTP,
	.name		= "mctp",
	.open		= mctp_serial_open,
	.close		= mctp_serial_close,

Annotation

Implementation Notes