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serial: 8250: Export ICR access helpers for internal use

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[ 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.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Maciej W. Rozycki
2022-04-18 16:27:27 +01:00
committed by Greg Kroah-Hartman
parent 403d469719
commit d98dd16d3d
2 changed files with 22 additions and 21 deletions
Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/tty/serial/8250/8250.h
View File

@@ -119,6 +119,28 @@ static inline void serial_out(struct uart_8250_port *up, int offset, int value)
up->port.serial_out(&up->port, offset, 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); void serial8250_clear_and_reinit_fifos(struct uart_8250_port *p);
static inline int serial_dl_read(struct uart_8250_port *up) static inline int serial_dl_read(struct uart_8250_port *up)

21
drivers/tty/serial/8250/8250_port.c
View File

@@ -529,27 +529,6 @@ 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. * FIFO support.
*/ */