From: Maciej W. Rozycki macro@orcam.me.uk
[ Upstream commit cb5a40e3143bc64437858b337273fd63cc42e9c2 ]
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 macro@orcam.me.uk Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181517500.9383@angie.orcam.me.... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 db784ace25d8..467372534d1c 100644 --- a/drivers/tty/serial/8250/8250.h +++ b/drivers/tty/serial/8250/8250.h @@ -120,6 +120,28 @@ 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 ddaf35daf316..291fd99bd7f1 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. */