Commit cb5a40e3 authored by Maciej W. Rozycki's avatar Maciej W. Rozycki Committed by Greg Kroah-Hartman
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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: default avatarMaciej W. Rozycki <macro@orcam.me.uk>
Reviewed-by: default avatarAndy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204181517500.9383@angie.orcam.me.uk


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1f32c65b

drivers/tty/serial/8250/8250.h

+22 −0
Original line number Diff line number Diff line
@@ -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)

drivers/tty/serial/8250/8250_port.c

+0 −21
Original line number Diff line number Diff line
@@ -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.

 */