serial: 8250: Export ICR access helpers for internal use

[ 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>

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index 6473361..0efe4df 100644 (file)
--- 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 4f66825..a5496bd 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -538,27 +538,6 @@ 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.
  */
 static void serial8250_clear_fifos(struct uart_8250_port *p)