Re: [PATCH 09/33] serial: 8250: remove CONFIG_SERIAL_8250_RSA inline macros from code

Ilpo Järvinen
2025-06-11T11:42:11Z

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

> All these:
> #ifdef CONFIG_SERIAL_8250_RSA
> ...
> #endif
>
> in the 8250 generic code distract the reader. Introduce empty inlines to
> handle the !CONFIG_SERIAL_8250_RSA case and handle the '#if's around the
> RSA functions definitions.
>
> This means rsa_autoconfig() and rsa_reset() functions were introduced to
> contain the particular code.
>
> Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
> ---
> drivers/tty/serial/8250/8250_port.c | 54 ++++++++++++++---------------
> 1 file changed, 27 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index f5407832e8a7..233316a88df2 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -738,6 +738,9 @@ static int __enable_rsa(struct uart_8250_port *up)
> return result;
> }
>
> +/*
> + * If this is an RSA port, see if we can kick it up to the higher speed clock.
> + */
> static void enable_rsa(struct uart_8250_port *up)
> {
> if (up->port.type == PORT_RSA) {

In general, a good change but it would also be nice to reverse all these
type check because then it would be immediately obvious the function does
nothing if it's not PORT_RSA.

> @@ -752,10 +755,9 @@ static void enable_rsa(struct uart_8250_port *up)
> }
>
> /*
> - * Attempts to turn off the RSA FIFO. Returns zero on failure.
> - * It is unknown why interrupts were disabled in here. However,
> - * the caller is expected to preserve this behaviour by grabbing
> - * the spinlock before calling this function.
> + * Attempts to turn off the RSA FIFO and resets the RSA board back to 115kbps compat mode. It is
> + * unknown why interrupts were disabled in here. However, the caller is expected to preserve this
> + * behaviour by grabbing the spinlock before calling this function.
> */
> static void disable_rsa(struct uart_8250_port *up)
> {
> @@ -780,6 +782,25 @@ static void disable_rsa(struct uart_8250_port *up)
> uart_port_unlock_irq(&up->port);
> }
> }
> +
> +static void rsa_autoconfig(struct uart_8250_port *up)
> +{
> + /* Only probe for RSA ports if we got the region. */
> + if (up->port.type == PORT_16550A && up->probe & UART_PROBE_RSA &&
> + __enable_rsa(up))
> + up->port.type = PORT_RSA;
> +}
> +
> +static void rsa_reset(struct uart_8250_port *up)
> +{
> + if (up->port.type == PORT_RSA)
> + serial_out(up, UART_RSA_FRR, 0);
> +}
> +#else
> +static inline void enable_rsa(struct uart_8250_port *up) {}
> +static inline void disable_rsa(struct uart_8250_port *up) {}
> +static inline void rsa_autoconfig(struct uart_8250_port *up) {}
> +static inline void rsa_reset(struct uart_8250_port *up) {}
> #endif /* CONFIG_SERIAL_8250_RSA */
>
> /*
> @@ -1267,14 +1288,7 @@ static void autoconfig(struct uart_8250_port *up)
> break;
> }
>
> -#ifdef CONFIG_SERIAL_8250_RSA
> - /*
> - * Only probe for RSA ports if we got the region.
> - */
> - if (port->type == PORT_16550A && up->probe & UART_PROBE_RSA &&
> - __enable_rsa(up))
> - port->type = PORT_RSA;
> -#endif
> + rsa_autoconfig(up);
>
> serial_out(up, UART_LCR, save_lcr);
>
> @@ -1289,10 +1303,7 @@ static void autoconfig(struct uart_8250_port *up)
> /*
> * Reset the UART.
> */
> -#ifdef CONFIG_SERIAL_8250_RSA
> - if (port->type == PORT_RSA)
> - serial_out(up, UART_RSA_FRR, 0);
> -#endif
> + rsa_reset(up);
> serial8250_out_MCR(up, save_mcr);
> serial8250_clear_fifos(up);
> serial_in(up, UART_RX);
> @@ -2248,13 +2259,7 @@ int serial8250_do_startup(struct uart_port *port)
> UART_DA830_PWREMU_MGMT_FREE);
> }
>
> -#ifdef CONFIG_SERIAL_8250_RSA
> - /*
> - * If this is an RSA port, see if we can kick it up to the
> - * higher speed clock.
> - */
> enable_rsa(up);
> -#endif
>
> /*
> * Clear the FIFO buffers and disable them.
> @@ -2521,12 +2526,7 @@ void serial8250_do_shutdown(struct uart_port *port)
> serial_port_in(port, UART_LCR) & ~UART_LCR_SBC);
> serial8250_clear_fifos(up);
>
> -#ifdef CONFIG_SERIAL_8250_RSA
> - /*
> - * Reset the RSA board back to 115kbps compat mode.
> - */
> disable_rsa(up);
> -#endif
>
> /*
> * Read data port to reset things, and then unlink from
>

--
i.