serial: 8250_port: Introduce UART_IIR_FIFO_ENABLED_16750

The UART_IIR_64BYTE_FIFO is always being used in conjunction with
UART_IIR_FIFO_ENABLED. Introduce a joined UART_IIR_FIFO_ENABLED_16750
definition and use it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20230911144308.4169752-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index fb891b67968f0fb61914293b8aeea0b00f68427b..a064698c2be07117b99852b8559ff02629a531b2 100644 (file)
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1008,12 +1008,11 @@ static void autoconfig_16550a(struct uart_8250_port *up)
                        serial_out(up, UART_LCR, 0);
                        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO |
                                   UART_FCR7_64BYTE);
-                       status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO |
-                                                            UART_IIR_FIFO_ENABLED);
+                       status1 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750;
                        serial_out(up, UART_FCR, 0);
                        serial_out(up, UART_LCR, 0);
 
-                       if (status1 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED))
+                       if (status1 == UART_IIR_FIFO_ENABLED_16750)
                                up->port.type = PORT_16550A_FSL64;
                        else
                                DEBUG_AUTOCONF("Motorola 8xxx DUART ");
@@ -1081,12 +1080,12 @@ static void autoconfig_16550a(struct uart_8250_port *up)
         */
        serial_out(up, UART_LCR, 0);
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
-       status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
+       status1 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750;
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
 
        serial_out(up, UART_LCR, UART_LCR_CONF_MODE_A);
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO | UART_FCR7_64BYTE);
-       status2 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
+       status2 = serial_in(up, UART_IIR) & UART_IIR_FIFO_ENABLED_16750;
        serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
 
        serial_out(up, UART_LCR, 0);
@@ -1094,7 +1093,7 @@ static void autoconfig_16550a(struct uart_8250_port *up)
        DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
 
        if (status1 == UART_IIR_FIFO_ENABLED_16550A &&
-           status2 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED_16550A)) {
+           status2 == UART_IIR_FIFO_ENABLED_16750) {
                up->port.type = PORT_16750;
                up->capabilities |= UART_CAP_AFE | UART_CAP_SLEEP;
                return;

diff --git a/include/uapi/linux/serial_reg.h b/include/uapi/linux/serial_reg.h
index 08b3527e1b9356408a119b917438982ed39c2b55..9c987b04e2d04b4a933f9b09e2b31af5b6fde95d 100644 (file)
--- a/include/uapi/linux/serial_reg.h
+++ b/include/uapi/linux/serial_reg.h
@@ -49,6 +49,7 @@
 #define  UART_IIR_FIFO_ENABLED_8250    0x00    /* 8250: no FIFO */
 #define  UART_IIR_FIFO_ENABLED_16550   0x80    /* 16550: (broken/unusable) FIFO */
 #define  UART_IIR_FIFO_ENABLED_16550A  0xc0    /* 16550A: FIFO enabled */
+#define  UART_IIR_FIFO_ENABLED_16750   0xe0    /* 16750: 64 bytes FIFO enabled */
 
 #define UART_FCR       2       /* Out: FIFO Control Register */
 #define UART_FCR_ENABLE_FIFO   0x01 /* Enable the FIFO */