167 строки
3.8 KiB
C
167 строки
3.8 KiB
C
/*
|
|
* udbg for for NS16550 compatable serial ports
|
|
*
|
|
* Copyright (C) 2001-2005 PPC 64 Team, IBM Corp
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
#include <linux/config.h>
|
|
#include <linux/types.h>
|
|
#include <asm/udbg.h>
|
|
#include <asm/io.h>
|
|
|
|
extern u8 real_readb(volatile u8 __iomem *addr);
|
|
extern void real_writeb(u8 data, volatile u8 __iomem *addr);
|
|
|
|
struct NS16550 {
|
|
/* this struct must be packed */
|
|
unsigned char rbr; /* 0 */
|
|
unsigned char ier; /* 1 */
|
|
unsigned char fcr; /* 2 */
|
|
unsigned char lcr; /* 3 */
|
|
unsigned char mcr; /* 4 */
|
|
unsigned char lsr; /* 5 */
|
|
unsigned char msr; /* 6 */
|
|
unsigned char scr; /* 7 */
|
|
};
|
|
|
|
#define thr rbr
|
|
#define iir fcr
|
|
#define dll rbr
|
|
#define dlm ier
|
|
#define dlab lcr
|
|
|
|
#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 */
|
|
|
|
#define LCR_DLAB 0x80
|
|
|
|
static volatile struct NS16550 __iomem *udbg_comport;
|
|
|
|
static void udbg_550_putc(char c)
|
|
{
|
|
if (udbg_comport) {
|
|
while ((in_8(&udbg_comport->lsr) & LSR_THRE) == 0)
|
|
/* wait for idle */;
|
|
out_8(&udbg_comport->thr, c);
|
|
if (c == '\n')
|
|
udbg_550_putc('\r');
|
|
}
|
|
}
|
|
|
|
static int udbg_550_getc_poll(void)
|
|
{
|
|
if (udbg_comport) {
|
|
if ((in_8(&udbg_comport->lsr) & LSR_DR) != 0)
|
|
return in_8(&udbg_comport->rbr);
|
|
else
|
|
return -1;
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
static int udbg_550_getc(void)
|
|
{
|
|
if (udbg_comport) {
|
|
while ((in_8(&udbg_comport->lsr) & LSR_DR) == 0)
|
|
/* wait for char */;
|
|
return in_8(&udbg_comport->rbr);
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
void udbg_init_uart(void __iomem *comport, unsigned int speed,
|
|
unsigned int clock)
|
|
{
|
|
unsigned int dll, base_bauds = clock / 16;
|
|
|
|
if (speed == 0)
|
|
speed = 9600;
|
|
dll = base_bauds / speed;
|
|
|
|
if (comport) {
|
|
udbg_comport = (struct NS16550 __iomem *)comport;
|
|
out_8(&udbg_comport->lcr, 0x00);
|
|
out_8(&udbg_comport->ier, 0xff);
|
|
out_8(&udbg_comport->ier, 0x00);
|
|
out_8(&udbg_comport->lcr, LCR_DLAB);
|
|
out_8(&udbg_comport->dll, dll & 0xff);
|
|
out_8(&udbg_comport->dlm, dll >> 8);
|
|
/* 8 data, 1 stop, no parity */
|
|
out_8(&udbg_comport->lcr, 0x03);
|
|
/* RTS/DTR */
|
|
out_8(&udbg_comport->mcr, 0x03);
|
|
/* Clear & enable FIFOs */
|
|
out_8(&udbg_comport->fcr ,0x07);
|
|
udbg_putc = udbg_550_putc;
|
|
udbg_getc = udbg_550_getc;
|
|
udbg_getc_poll = udbg_550_getc_poll;
|
|
}
|
|
}
|
|
|
|
unsigned int udbg_probe_uart_speed(void __iomem *comport, unsigned int clock)
|
|
{
|
|
unsigned int dll, dlm, divisor, prescaler, speed;
|
|
u8 old_lcr;
|
|
volatile struct NS16550 __iomem *port = comport;
|
|
|
|
old_lcr = in_8(&port->lcr);
|
|
|
|
/* select divisor latch registers. */
|
|
out_8(&port->lcr, LCR_DLAB);
|
|
|
|
/* now, read the divisor */
|
|
dll = in_8(&port->dll);
|
|
dlm = in_8(&port->dlm);
|
|
divisor = dlm << 8 | dll;
|
|
|
|
/* check prescaling */
|
|
if (in_8(&port->mcr) & 0x80)
|
|
prescaler = 4;
|
|
else
|
|
prescaler = 1;
|
|
|
|
/* restore the LCR */
|
|
out_8(&port->lcr, old_lcr);
|
|
|
|
/* calculate speed */
|
|
speed = (clock / prescaler) / (divisor * 16);
|
|
|
|
/* sanity check */
|
|
if (speed < 0 || speed > (clock / 16))
|
|
speed = 9600;
|
|
|
|
return speed;
|
|
}
|
|
|
|
#ifdef CONFIG_PPC_MAPLE
|
|
void udbg_maple_real_putc(char c)
|
|
{
|
|
if (udbg_comport) {
|
|
while ((real_readb(&udbg_comport->lsr) & LSR_THRE) == 0)
|
|
/* wait for idle */;
|
|
real_writeb(c, &udbg_comport->thr); eieio();
|
|
if (c == '\n')
|
|
udbg_maple_real_putc('\r');
|
|
}
|
|
}
|
|
|
|
void __init udbg_init_maple_realmode(void)
|
|
{
|
|
udbg_comport = (volatile struct NS16550 __iomem *)0xf40003f8;
|
|
|
|
udbg_putc = udbg_maple_real_putc;
|
|
udbg_getc = NULL;
|
|
udbg_getc_poll = NULL;
|
|
}
|
|
#endif /* CONFIG_PPC_MAPLE */
|