From 0a8d37b166febac12b96cfb52563db461e0af2cc Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" Date: Mon, 18 Apr 2022 16:27:27 +0100 Subject: [PATCH] serial: 8250: Export ICR access helpers for internal use Make ICR access helpers available outside 8250_port.c, however retain them as ordinary static functions so as not to regress code generation. This is because `serial_icr_write' is currently automatically inlined by GCC, however `serial_icr_read' is not. Making them both static inline would grow code produced, e.g.: $ i386-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 15065 3378 0 18443 8250_port-old.o 15289 3378 0 18667 8250_port-new.o and: $ riscv64-linux-gnu-size --format=gnu 8250_port-{old,new}.o text data bss total filename 16980 5306 0 22286 8250_port-old.o 17124 5306 0 22430 8250_port-new.o while making them external would needlessly add a new module interface and lose the benefit from `serial_icr_write' getting inlined outside 8250_port.o. Signed-off-by: Maciej W. Rozycki Reviewed-by: Andy Shevchenko Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181517500.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/8250/8250.h | 22 ++++++++++++++++++++++ drivers/tty/serial/8250/8250_port.c | 21 --------------------- 2 files changed, 22 insertions(+), 21 deletions(-) diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h index 5a4e05c0e552a..d70adaa3b1172 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -123,6 +123,28 @@ static inline void serial_out(struct uart_8250_port *up, int offset, int value) up->port.serial_out(&up->port, offset, value); } +/* + * For the 16C950 + */ +static void serial_icr_write(struct uart_8250_port *up, int offset, int value) +{ + serial_out(up, UART_SCR, offset); + serial_out(up, UART_ICR, value); +} + +static unsigned int __maybe_unused serial_icr_read(struct uart_8250_port *up, + int offset) +{ + unsigned int value; + + serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); + serial_out(up, UART_SCR, offset); + value = serial_in(up, UART_ICR); + serial_icr_write(up, UART_ACR, up->acr); + + return value; +} + void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p); static inline int serial_dl_read(struct uart_8250_port *up) diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c index 9b1d47ef15c05..5591f18f2ea95 100644 --- a/drivers/tty/serial/8250/8250_port.c +++ b/drivers/tty/serial/8250/8250_port.c @@ -537,27 +537,6 @@ serial_port_out_sync(struct uart_port *p, int offset, int value) } } -/* - * For the 16C950 - */ -static void serial_icr_write(struct uart_8250_port *up, int offset, int value) -{ - serial_out(up, UART_SCR, offset); - serial_out(up, UART_ICR, value); -} - -static unsigned int serial_icr_read(struct uart_8250_port *up, int offset) -{ - unsigned int value; - - serial_icr_write(up, UART_ACR, up->acr | UART_ACR_ICRRD); - serial_out(up, UART_SCR, offset); - value = serial_in(up, UART_ICR); - serial_icr_write(up, UART_ACR, up->acr); - - return value; -} - /* * FIFO support. */ -- 2.39.5