/*
 * include/linux/serial.h
 *
 * Copyright (C) 1992, 1994 by Theodore Ts'o.
 * 
 * Redistribution of this file is permitted under the terms of the GNU 
 * Public License (GPL)
 * 
 * These are the UART port assignments, expressed as offsets from the base
 * register.  These assignments should hold for any serial port based on
 * a 8250, 16450, or 16550(A).
 */

#ifndef _LINUX_SERIAL_REG_H
#define _LINUX_SERIAL_REG_H

#define UART_RX		0	/* In:  Receive buffer (DLAB=0) */
#define UART_TX		0	/* Out: Transmit buffer (DLAB=0) */
#define UART_DLL	0	/* Out: Divisor Latch Low (DLAB=1) */
#define UART_DLM	1	/* Out: Divisor Latch High (DLAB=1) */
#define UART_IER	1	/* Out: Interrupt Enable Register */
#define UART_IIR	2	/* In:  Interrupt ID Register */
#define UART_FCR	2	/* Out: FIFO Control Register */
#define UART_EFR	2	/* I/O: Extended Features Register */
				/* (DLAB=1, 16C660 only) */
#define UART_LCR	3	/* Out: Line Control Register */
#define UART_MCR	4	/* Out: Modem Control Register */
#define UART_LSR	5	/* In:  Line Status Register */
#define UART_MSR	6	/* In:  Modem Status Register */
#define UART_SCR	7	/* I/O: Scratch Register */

/*
 * These are the definitions for the FIFO Control Register
 * (16650 only)
 */
#define UART_FCR_ENABLE_FIFO	0x01 /* Enable the FIFO */
#define UART_FCR_CLEAR_RCVR	0x02 /* Clear the RCVR FIFO */
#define UART_FCR_CLEAR_XMIT	0x04 /* Clear the XMIT FIFO */
#define UART_FCR_DMA_SELECT	0x08 /* For DMA applications */
#define UART_FCR_TRIGGER_MASK	0xC0 /* Mask for the FIFO trigger range */
#define UART_FCR_TRIGGER_1	0x00 /* Mask for trigger set at 1 */
#define UART_FCR_TRIGGER_4	0x40 /* Mask for trigger set at 4 */
#define UART_FCR_TRIGGER_8	0x80 /* Mask for trigger set at 8 */
#define UART_FCR_TRIGGER_14	0xC0 /* Mask for trigger set at 14 */
/* 16650 redefinitions */
#define UART_FCR6_R_TRIGGER_8	0x00 /* Mask for receive trigger set at 1 */
#define UART_FCR6_R_TRIGGER_16	0x40 /* Mask for receive trigger set at 4 */
#define UART_FCR6_R_TRIGGER_24  0x80 /* Mask for receive trigger set at 8 */
#define UART_FCR6_R_TRIGGER_28	0xC0 /* Mask for receive trigger set at 14 */
#define UART_FCR6_T_TRIGGER_16	0x00 /* Mask for transmit trigger set at 16 */
#define UART_FCR6_T_TRIGGER_8	0x10 /* Mask for transmit trigger set at 8 */
#define UART_FCR6_T_TRIGGER_24  0x20 /* Mask for transmit trigger set at 24 */
#define UART_FCR6_T_TRIGGER_30	0x30 /* Mask for transmit trigger set at 30 */

/*
 * These are the definitions for the Line Control Register
 * 
 * Note: if the word length is 5 bits (UART_LCR_WLEN5), then setting 
 * UART_LCR_STOP will select 1.5 stop bits, not 2 stop bits.
 */
#define UART_LCR_DLAB	0x80	/* Divisor latch access bit */
#define UART_LCR_SBC	0x40	/* Set break control */
#define UART_LCR_SPAR	0x20	/* Stick parity (?) */
#define UART_LCR_EPAR	0x10	/* Even parity select */
#define UART_LCR_PARITY	0x08	/* Parity Enable */
#define UART_LCR_STOP	0x04	/* Stop bits: 0=1 stop bit, 1= 2 stop bits */
#define UART_LCR_WLEN5  0x00	/* Wordlength: 5 bits */
#define UART_LCR_WLEN6  0x01	/* Wordlength: 6 bits */
#define UART_LCR_WLEN7  0x02	/* Wordlength: 7 bits */
#define UART_LCR_WLEN8  0x03	/* Wordlength: 8 bits */

/*
 * These are the definitions for the Line Status Register
 */
#define UART_LSR_TEMT	0x40	/* Transmitter empty */
#define UART_LSR_THRE	0x20	/* Transmit-hold-register empty */
#define UART_LSR_BI	0x10	/* Break interrupt indicator */
#define UART_LSR_FE	0x08	/* Frame error indicator */
#define UART_LSR_PE	0x04	/* Parity error indicator */
#define UART_LSR_OE	0x02	/* Overrun error indicator */
#define UART_LSR_DR	0x01	/* Receiver data ready */

/*
 * These are the definitions for the Interrupt Identification Register
 */
#define UART_IIR_NO_INT	0x01	/* No interrupts pending */
#define UART_IIR_ID	0x06	/* Mask for the interrupt ID */

#define UART_IIR_MSI	0x00	/* Modem status interrupt */
#define UART_IIR_THRI	0x02	/* Transmitter holding register empty */
#define UART_IIR_RDI	0x04	/* Receiver data interrupt */
#define UART_IIR_RLSI	0x06	/* Receiver line status interrupt */

/*
 * These are the definitions for the Interrupt Enable Register
 */
#define UART_IER_MSI	0x08	/* Enable Modem status interrupt */
#define UART_IER_RLSI	0x04	/* Enable receiver line status interrupt */
#define UART_IER_THRI	0x02	/* Enable Transmitter holding register int. */
#define UART_IER_RDI	0x01	/* Enable receiver data interrupt */

/*
 * These are the definitions for the Modem Control Register
 */
#define UART_MCR_LOOP	0x10	/* Enable loopback test mode */
#define UART_MCR_OUT2	0x08	/* Out2 complement */
#define UART_MCR_OUT1	0x04	/* Out1 complement */
#define UART_MCR_RTS	0x02	/* RTS complement */
#define UART_MCR_DTR	0x01	/* DTR complement */

/*
 * These are the definitions for the Modem Status Register
 */
#define UART_MSR_DCD	0x80	/* Data Carrier Detect */
#define UART_MSR_RI	0x40	/* Ring Indicator */
#define UART_MSR_DSR	0x20	/* Data Set Ready */
#define UART_MSR_CTS	0x10	/* Clear to Send */
#define UART_MSR_DDCD	0x08	/* Delta DCD */
#define UART_MSR_TERI	0x04	/* Trailing edge ring indicator */
#define UART_MSR_DDSR	0x02	/* Delta DSR */
#define UART_MSR_DCTS	0x01	/* Delta CTS */
#define UART_MSR_ANY_DELTA 0x0F	/* Any of the delta bits! */

/*
 * These are the definitions for the Extended Features Register
 * (StarTech 16C660 only, when DLAB=1)
 */
#define UART_EFR_CTS	0x80	/* CTS flow control */
#define UART_EFR_RTS	0x40	/* RTS flow control */
#define UART_EFR_SCD	0x20	/* Special character detect */
#define UART_EFR_ENI	0x10	/* Enhanced Interrupt */
/*
 * the low four bits control software flow control
 */

#endif /* _LINUX_SERIAL_REG_H */