Commit afd216ca authored by Ilpo Järvinen's avatar Ilpo Järvinen Committed by Greg Kroah-Hartman
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serial: 8250: Define IIR 64 byte bit & cleanup related code 



16750 indicates 64 bytes FIFO with a IIR bit. Add define for it and
make related code more obvious.

Signed-off-by: default avatarIlpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20221125130509.8482-6-ilpo.jarvinen@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3398cc4f

drivers/tty/serial/8250/8250_port.c

+9 −5
Original line number Diff line number Diff line
@@ -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;

include/uapi/linux/serial_reg.h

+1 −0
Original line number Diff line number Diff line
@@ -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_ENABLED_16550	0x80	/* 16550: (broken/unusable) FIFO */