[PATCH 10/33] serial: 8250: invert conditions in RSA functions

Jiri Slaby (SUSE)
2025-06-11T10:03:46Z

The code can short-return in case something does not hold. So invert the
conditions and return in those cases immediately. This makes the code
flow more natural and less nested.

Signed-off-by: Jiri Slaby (SUSE) <jirislaby@kernel.org>
---
drivers/tty/serial/8250/8250_port.c | 59 +++++++++++++++++------------
1 file changed, 34 insertions(+), 25 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 233316a88df2..e7652d62ab2f 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -743,15 +743,16 @@ static int __enable_rsa(struct uart_8250_port *up)
*/
static void enable_rsa(struct uart_8250_port *up)
{
- if (up->port.type == PORT_RSA) {
- if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
- uart_port_lock_irq(&up->port);
- __enable_rsa(up);
- uart_port_unlock_irq(&up->port);
- }
- if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
- serial_out(up, UART_RSA_FRR, 0);
+ if (up->port.type != PORT_RSA)
+ return;
+
+ if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16) {
+ uart_port_lock_irq(&up->port);
+ __enable_rsa(up);
+ uart_port_unlock_irq(&up->port);
}
+ if (up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16)
+ serial_out(up, UART_RSA_FRR, 0);
}

/*
@@ -764,37 +765,45 @@ static void disable_rsa(struct uart_8250_port *up)
unsigned char mode;
int result;

- if (up->port.type == PORT_RSA &&
- up->port.uartclk == SERIAL_RSA_BAUD_BASE * 16) {
- uart_port_lock_irq(&up->port);
+ if (up->port.type != PORT_RSA)
+ return;

- mode = serial_in(up, UART_RSA_MSR);
- result = !(mode & UART_RSA_MSR_FIFO);
+ if (up->port.uartclk != SERIAL_RSA_BAUD_BASE * 16)
+ return;

- if (!result) {
- serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
- mode = serial_in(up, UART_RSA_MSR);
- result = !(mode & UART_RSA_MSR_FIFO);
- }
+ uart_port_lock_irq(&up->port);
+ mode = serial_in(up, UART_RSA_MSR);
+ result = !(mode & UART_RSA_MSR_FIFO);

- if (result)
- up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
- uart_port_unlock_irq(&up->port);
+ if (!result) {
+ serial_out(up, UART_RSA_MSR, mode & ~UART_RSA_MSR_FIFO);
+ mode = serial_in(up, UART_RSA_MSR);
+ result = !(mode & UART_RSA_MSR_FIFO);
}
+
+ if (result)
+ up->port.uartclk = SERIAL_RSA_BAUD_BASE_LO * 16;
+ uart_port_unlock_irq(&up->port);
}

static void rsa_autoconfig(struct uart_8250_port *up)
{
/* Only probe for RSA ports if we got the region. */
- if (up->port.type == PORT_16550A && up->probe & UART_PROBE_RSA &&
- __enable_rsa(up))
+ if (up->port.type != PORT_16550A)
+ return;
+ if (!(up->probe & UART_PROBE_RSA))
+ return;
+
+ if (__enable_rsa(up))
up->port.type = PORT_RSA;
}

static void rsa_reset(struct uart_8250_port *up)
{
- if (up->port.type == PORT_RSA)
- serial_out(up, UART_RSA_FRR, 0);
+ if (up->port.type != PORT_RSA)
+ return;
+
+ serial_out(up, UART_RSA_FRR, 0);
}
#else
static inline void enable_rsa(struct uart_8250_port *up) {}
--
2.49.0