int serial8250_register_8250_port()

in serial/8250/8250_core.c [973:1117]

• 118 lines of code
• 31 McCabe index (conditional complexity)

int serial8250_register_8250_port(const struct uart_8250_port *up)
{
	struct uart_8250_port *uart;
	int ret = -ENOSPC;

	if (up->port.uartclk == 0)
		return -EINVAL;

	mutex_lock(&serial_mutex);

	uart = serial8250_find_match_or_unused(&up->port);
	if (uart && uart->port.type != PORT_8250_CIR) {
		struct mctrl_gpios *gpios;

		if (uart->port.dev)
			uart_remove_one_port(&serial8250_reg, &uart->port);

		uart->port.iobase       = up->port.iobase;
		uart->port.membase      = up->port.membase;
		uart->port.irq          = up->port.irq;
		uart->port.irqflags     = up->port.irqflags;
		uart->port.uartclk      = up->port.uartclk;
		uart->port.fifosize     = up->port.fifosize;
		uart->port.regshift     = up->port.regshift;
		uart->port.iotype       = up->port.iotype;
		uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
		uart->bugs		= up->bugs;
		uart->port.mapbase      = up->port.mapbase;
		uart->port.mapsize      = up->port.mapsize;
		uart->port.private_data = up->port.private_data;
		uart->tx_loadsz		= up->tx_loadsz;
		uart->capabilities	= up->capabilities;
		uart->port.throttle	= up->port.throttle;
		uart->port.unthrottle	= up->port.unthrottle;
		uart->port.rs485_config	= up->port.rs485_config;
		uart->port.rs485	= up->port.rs485;
		uart->rs485_start_tx	= up->rs485_start_tx;
		uart->rs485_stop_tx	= up->rs485_stop_tx;
		uart->dma		= up->dma;

		/* Take tx_loadsz from fifosize if it wasn't set separately */
		if (uart->port.fifosize && !uart->tx_loadsz)
			uart->tx_loadsz = uart->port.fifosize;

		if (up->port.dev) {
			uart->port.dev = up->port.dev;
			ret = uart_get_rs485_mode(&uart->port);
			if (ret)
				goto err;
		}

		if (up->port.flags & UPF_FIXED_TYPE)
			uart->port.type = up->port.type;

		/*
		 * Only call mctrl_gpio_init(), if the device has no ACPI
		 * companion device
		 */
		if (!has_acpi_companion(uart->port.dev)) {
			gpios = mctrl_gpio_init(&uart->port, 0);
			if (IS_ERR(gpios)) {
				ret = PTR_ERR(gpios);
				goto err;
			} else {
				uart->gpios = gpios;
			}
		}

		serial8250_set_defaults(uart);

		/* Possibly override default I/O functions.  */
		if (up->port.serial_in)
			uart->port.serial_in = up->port.serial_in;
		if (up->port.serial_out)
			uart->port.serial_out = up->port.serial_out;
		if (up->port.handle_irq)
			uart->port.handle_irq = up->port.handle_irq;
		/*  Possibly override set_termios call */
		if (up->port.set_termios)
			uart->port.set_termios = up->port.set_termios;
		if (up->port.set_ldisc)
			uart->port.set_ldisc = up->port.set_ldisc;
		if (up->port.get_mctrl)
			uart->port.get_mctrl = up->port.get_mctrl;
		if (up->port.set_mctrl)
			uart->port.set_mctrl = up->port.set_mctrl;
		if (up->port.get_divisor)
			uart->port.get_divisor = up->port.get_divisor;
		if (up->port.set_divisor)
			uart->port.set_divisor = up->port.set_divisor;
		if (up->port.startup)
			uart->port.startup = up->port.startup;
		if (up->port.shutdown)
			uart->port.shutdown = up->port.shutdown;
		if (up->port.pm)
			uart->port.pm = up->port.pm;
		if (up->port.handle_break)
			uart->port.handle_break = up->port.handle_break;
		if (up->dl_read)
			uart->dl_read = up->dl_read;
		if (up->dl_write)
			uart->dl_write = up->dl_write;

		if (uart->port.type != PORT_8250_CIR) {
			if (serial8250_isa_config != NULL)
				serial8250_isa_config(0, &uart->port,
						&uart->capabilities);

			serial8250_apply_quirks(uart);
			ret = uart_add_one_port(&serial8250_reg,
						&uart->port);
			if (ret)
				goto err;

			ret = uart->port.line;
		} else {
			dev_info(uart->port.dev,
				"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
				uart->port.iobase,
				(unsigned long long)uart->port.mapbase,
				uart->port.irq);

			ret = 0;
		}

		/* Initialise interrupt backoff work if required */
		if (up->overrun_backoff_time_ms > 0) {
			uart->overrun_backoff_time_ms =
				up->overrun_backoff_time_ms;
			INIT_DELAYED_WORK(&uart->overrun_backoff,
					serial_8250_overrun_backoff_work);
		} else {
			uart->overrun_backoff_time_ms = 0;
		}
	}

	mutex_unlock(&serial_mutex);

	return ret;

err:
	uart->port.dev = NULL;
	mutex_unlock(&serial_mutex);
	return ret;
}