16750 indicates 64 bytes FIFO with a IIR bit. Add define for it and
make related code more obvious.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_port.c | 14 +++++++++-----
include/uapi/linux/serial_reg.h | 1 +
2 files changed, 10 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 6d343b15bc58..764043931a99 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1050,11 +1050,12 @@ 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) >> 5;
+ status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO |
+ UART_IIR_FIFO_ENABLED);
serial_out(up, UART_FCR, 0);
serial_out(up, UART_LCR, 0);
- if (status1 == 7)
+ if (status1 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED))
up->port.type = PORT_16550A_FSL64;
else
DEBUG_AUTOCONF("Motorola 8xxx DUART ");
@@ -1122,17 +1123,20 @@ 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) >> 5;
+ status1 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
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) >> 5;
+ status2 = serial_in(up, UART_IIR) & (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED);
serial_out(up, UART_FCR, UART_FCR_ENABLE_FIFO);
+
serial_out(up, UART_LCR, 0);
DEBUG_AUTOCONF("iir1=%d iir2=%d ", status1, status2);
- if (status1 == 6 && status2 == 7) {
+ if (status1 == UART_IIR_FIFO_ENABLED_16550A &&
+ status2 == (UART_IIR_64BYTE_FIFO | UART_IIR_FIFO_ENABLED_16550A)) {
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 a63c124b7fdc..21ae5b930c7b 100644
--- a/include/uapi/linux/serial_reg.h
+++ b/include/uapi/linux/serial_reg.h
@@ -44,6 +44,7 @@
#define UART_IIR_RX_TIMEOUT 0x0c /* OMAP RX Timeout interrupt */
#define UART_IIR_XOFF 0x10 /* OMAP XOFF/Special Character */
#define UART_IIR_CTS_RTS_DSR 0x20 /* OMAP CTS/RTS/DSR Change */
+#define UART_IIR_64BYTE_FIFO 0x20 /* 16750 64 bytes FIFO */
#define UART_IIR_FIFO_ENABLED 0xc0 /* FIFOs enabled / port type identification */
#define UART_IIR_FIFO_ENABLED_8250 0x00 /* 8250: no FIFO */
#define UART_IIR_FIFO_EAABLED_16550 0x80 /* 16550: (broken/unusable) FIFO */
--
2.30.2
