ns16550.h

Linux2.4.27在AT91RM9200下的U-BOOT代码。可以在Redhat9等版本下使用。适合ARM学习者使用。

/*
 * NS16550 Serial Port
 * originally from linux source (arch/ppc/boot/ns16550.h)
 * modified slightly to
 * have addresses as offsets from CFG_ISA_BASE
 * added a few more definitions
 * added prototypes for ns16550.c
 * reduced no of com ports to 2
 * modifications (c) Rob Taylor, Flying Pig Systems. 2000.
 * further modified to support the 8245 duart
 * modifications (c) Paul Jimenez, Musenki, Inc. 2001.
 */


struct NS16550 {
	unsigned char rbrthrdlb;	/* 0 */
	unsigned char ierdmb;		/* 1 */
	unsigned char iirfcrafr;	/* 2 */
	unsigned char lcr;		/* 3 */
	unsigned char mcr;		/* 4 */
	unsigned char lsr;		/* 5 */
	unsigned char msr;		/* 6 */
	unsigned char scr;		/* 7 */
	unsigned char reserved[2];	/* 8 & 9 */
	unsigned char dsr;		/* 10 */
	unsigned char dcr;		/* 11 */
};


#define rbr rbrthrdlb
#define thr rbrthrdlb
#define dll rbrthrdlb
#define ier ierdmb
#define dlm ierdmb
#define iir iirfcrafr
#define fcr iirfcrafr
#define afr iirfcrafr

#define FCR_FIFO_EN     0x01	/*fifo enable */
#define FCR_RXSR        0x02	/*reciever soft reset */
#define FCR_TXSR        0x04	/*transmitter soft reset */
#define FCR_DMS		0x08	/* DMA Mode Select */

#define MCR_RTS         0x02	/* Readyu to Send */
#define MCR_LOOP	0x10	/* Local loopback mode enable */
/* #define MCR_DTR         0x01    noton 8245 duart */
/* #define MCR_DMA_EN      0x04    noton 8245 duart */
/* #define MCR_TX_DFR      0x08    noton 8245 duart */

#define LCR_WLS_MSK 0x03	/* character length slect mask */
#define LCR_WLS_5   0x00	/* 5 bit character length */
#define LCR_WLS_6   0x01	/* 6 bit character length */
#define LCR_WLS_7   0x02	/* 7 bit character length */
#define LCR_WLS_8   0x03	/* 8 bit character length */
#define LCR_STB     0x04	/* Number of stop Bits, off = 1, on = 1.5 or 2) */
#define LCR_PEN     0x08	/* Parity eneble */
#define LCR_EPS     0x10	/* Even Parity Select */
#define LCR_STKP    0x20	/* Stick Parity */
#define LCR_SBRK    0x40	/* Set Break */
#define LCR_BKSE    0x80	/* Bank select enable - aka DLAB on 8245 */

#define LSR_DR      0x01	/* Data ready */
#define LSR_OE      0x02	/* Overrun */
#define LSR_PE      0x04	/* Parity error */
#define LSR_FE      0x08	/* Framing error */
#define LSR_BI      0x10	/* Break */
#define LSR_THRE    0x20	/* Xmit holding register empty */
#define LSR_TEMT    0x40	/* Xmitter empty */
#define LSR_ERR     0x80	/* Error */

/* useful defaults for LCR*/
#define LCR_8N1     0x03


volatile struct NS16550 *NS16550_init (int chan, int baud_divisor);
void NS16550_putc (volatile struct NS16550 *com_port, unsigned char c);
unsigned char NS16550_getc (volatile struct NS16550 *com_port);
int NS16550_tstc (volatile struct NS16550 *com_port);
void NS16550_reinit (volatile struct NS16550 *com_port, int baud_divisor);