Re: [PATCH 30/33] serial: 8250: invert serial8250_register_8250_port() CIR condition

Ilpo Järvinen
2025-06-11T13:21:27Z

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On Wed, 11 Jun 2025, Jiri Slaby (SUSE) wrote:

> There is no point in a long 'if' in serial8250_register_8250_port() to
> just return ENOSPC for PORT_8250_CIR ports. Invert the condition and
> return immediately.
>
> 'gpios' variable was moved to its set location.
>
> And return ENODEV instead of ENOSPC. The latter is a leftover from the
> previous find-uart 'if'. The former makes a lot more sense in this case.
>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
> drivers/tty/serial/8250/8250_core.c | 253 ++++++++++++++--------------
> 1 file changed, 127 insertions(+), 126 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
> index 2bac9c7827de..10f25bae9f46 100644
> --- a/drivers/tty/serial/8250/8250_core.c
> +++ b/drivers/tty/serial/8250/8250_core.c
> @@ -725,139 +725,140 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
> nr_uarts++;
> }
>
> - if (uart->port.type != PORT_8250_CIR) {
> - struct mctrl_gpios *gpios;
> -
> - if (uart->port.dev)
> - uart_remove_one_port(&serial8250_reg, &uart->port);
> -
> - uart->port.ctrl_id = up->port.ctrl_id;
> - uart->port.port_id = up->port.port_id;
> - 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_supported = up->port.rs485_supported;
> - uart->port.rs485 = up->port.rs485;
> - uart->rs485_start_tx = up->rs485_start_tx;
> - uart->rs485_stop_tx = up->rs485_stop_tx;
> - uart->lsr_save_mask = up->lsr_save_mask;
> - 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 (uart->port.type == PORT_8250_CIR) {
> + ret = -ENODEV;
> + goto unlock;
> + }
>
> - if (up->port.flags & UPF_FIXED_TYPE)
> - uart->port.type = up->port.type;
> + if (uart->port.dev)
> + uart_remove_one_port(&serial8250_reg, &uart->port);
> +
> + uart->port.ctrl_id = up->port.ctrl_id;
> + uart->port.port_id = up->port.port_id;
> + 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_supported = up->port.rs485_supported;
> + uart->port.rs485 = up->port.rs485;
> + uart->rs485_start_tx = up->rs485_start_tx;
> + uart->rs485_stop_tx = up->rs485_stop_tx;
> + uart->lsr_save_mask = up->lsr_save_mask;
> + 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;
> + }
>
> - /*
> - * 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;
> - }
> - }
> + if (up->port.flags & UPF_FIXED_TYPE)
> + uart->port.type = up->port.type;
>
> - 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 (uart_console_registered(&uart->port))
> - pm_runtime_get_sync(uart->port.dev);
> -
> - 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;
> + /*
> + * Only call mctrl_gpio_init(), if the device has no ACPI
> + * companion device
> + */
> + if (!has_acpi_companion(uart->port.dev)) {
> + struct mctrl_gpios *gpios = mctrl_gpio_init(&uart->port, 0);
> + if (IS_ERR(gpios)) {
> + ret = PTR_ERR(gpios);
> + goto err;
> } 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;
> + uart->gpios = gpios;
> }
> + }
>
> - if (!uart->lsr_save_mask)
> - uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
> + 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;
>
> - /* 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;
> - }
> + if (uart->port.type != PORT_8250_CIR) {
> + if (uart_console_registered(&uart->port))
> + pm_runtime_get_sync(uart->port.dev);
> +
> + 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;
> + }
> +
> + if (!uart->lsr_save_mask)
> + uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
> +
> + /* 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;
> }
>
> unlock:
>

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

--
i.