Retro68/gcc/libgloss/mips/cma101.c
2012-03-27 01:51:53 +02:00

315 lines
8.8 KiB
C

/*
* cma101.c -- lo-level support for Cogent CMA101 development board.
*
* Copyright (c) 1996, 2001, 2002 Cygnus Support
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#ifdef __mips16
/* The assembler portions of this file need to be re-written to
support mips16, if and when that seems useful.
*/
#error cma101.c can not be compiled -mips16
#endif
#include <time.h> /* standard ANSI time routines */
/* Normally these would appear in a header file for external
use. However, we are only building a simple example world at the
moment: */
#include "regs.S"
#if defined(MIPSEB)
#define BYTEREG(b,o) ((volatile unsigned char *)(PHYS_TO_K1((b) + (o) + 7)))
#endif /* MIPSEB */
#if defined(MIPSEL)
#define BYTEREG(b,o) ((volatile unsigned char *)(PHYS_TO_K1((b) + (o))))
#endif /* MIPSEL */
/* I/O addresses: */
#define RTCLOCK_BASE (0x0E800000) /* Mk48T02 NVRAM/RTC */
#define UART_BASE (0x0E900000) /* NS16C552 DUART */
#define LCD_BASE (0x0EB00000) /* Alphanumeric display */
/* LCD panel manifests: */
#define LCD_DATA BYTEREG(LCD_BASE,0)
#define LCD_CMD BYTEREG(LCD_BASE,8)
#define LCD_STAT_BUSY (0x80)
#define LCD_SET_DDADDR (0x80)
/* RTC manifests */
/* The lo-offsets are the NVRAM locations (0x7F8 bytes) */
#define RTC_CONTROL BYTEREG(RTCLOCK_BASE,0x3FC0)
#define RTC_SECS BYTEREG(RTCLOCK_BASE,0x3FC8)
#define RTC_MINS BYTEREG(RTCLOCK_BASE,0x3FD0)
#define RTC_HOURS BYTEREG(RTCLOCK_BASE,0x3FD8)
#define RTC_DAY BYTEREG(RTCLOCK_BASE,0x3FE0)
#define RTC_DATE BYTEREG(RTCLOCK_BASE,0x3FE8)
#define RTC_MONTH BYTEREG(RTCLOCK_BASE,0x3FF0)
#define RTC_YEAR BYTEREG(RTCLOCK_BASE,0x3FF8)
#define RTC_CTL_LOCK_READ (0x40) /* lock RTC whilst reading */
#define RTC_CTL_LOCK_WRITE (0x80) /* lock RTC whilst writing */
/* Macro to force out-standing memory transfers to complete before
next sequence. For the moment we assume that the processor in the
CMA101 board supports at least ISA II. */
#define DOSYNC() asm(" .set mips2 ; sync ; .set mips0")
/* We disable interrupts by writing zero to all of the masks, and the
global interrupt enable bit: */
#define INTDISABLE(sr,tmp) asm("\
.set mips2 ; \
mfc0 %0,$12 ; \
lui %1,0xffff ; \
ori %1,%1,0xfffe ; \
and %1, %0, %1 ; \
mtc0 %1,$12 ; \
.set mips0" : "=d" (sr), "=d" (tmp))
#define INTRESTORE(sr) asm("\
.set mips2 ; \
mtc0 %0,$12 ; \
.set mips0" : : "d" (sr))
/* TODO:FIXME: The CPU card support should be in separate source file
from the standard CMA101 support provided in this file. */
/* The CMA101 board being used contains a CMA257 Vr4300 CPU:
MasterClock is at 33MHz. PClock is derived from MasterClock by
multiplying by the ratio defined by the DivMode pins:
DivMode(1:0) MasterClock PClock Ratio
00 100MHz 100MHz 1:1
01 100MHz 150MHz 1.5:1
10 100MHz 200MHz 2:1
11 100Mhz 300MHz 3:1
Are these pins reflected in the EC bits in the CONFIG register? or
is that talking about a different clock multiplier?
110 = 1
111 = 1.5
000 = 2
001 = 3
(all other values are undefined)
*/
#define MASTERCLOCK (33) /* ticks per uS */
unsigned int pclock; /* number of PClock ticks per uS */
void
set_pclock (void)
{
unsigned int config;
asm volatile ("mfc0 %0,$16 ; nop ; nop" : "=r" (config)); /* nasty CP0 register constant */
switch ((config >> 28) & 0x7) {
case 0x7 : /* 1.5:1 */
pclock = (MASTERCLOCK + (MASTERCLOCK / 2));
break;
case 0x0 : /* 2:1 */
pclock = (2 * MASTERCLOCK);
break;
case 0x1 : /* 3:1 */
pclock = (3 * MASTERCLOCK);
break;
case 0x6 : /* 1:1 */
default : /* invalid configuration, so assume the lowest */
pclock = MASTERCLOCK;
break;
}
return;
}
#define PCLOCK_WAIT(x) __cpu_timer_poll((x) * pclock)
/* NOTE: On the Cogent CMA101 board the LCD controller will sometimes
return not-busy, even though it is. The work-around is to perform a
~50uS delay before checking the busy signal. */
static int
lcd_busy (void)
{
PCLOCK_WAIT(50); /* 50uS delay */
return(*LCD_CMD & LCD_STAT_BUSY);
}
/* Note: This code *ASSUMES* that the LCD has already been initialised
by the monitor. It only provides code to write to the LCD, and is
not a complete device driver. */
void
lcd_display (int line, const char *msg)
{
int n;
if (lcd_busy ())
return;
*LCD_CMD = (LCD_SET_DDADDR | (line == 1 ? 0x40 : 0x00));
for (n = 0; n < 16; n++) {
if (lcd_busy ())
return;
if (*msg)
*LCD_DATA = *msg++;
else
*LCD_DATA = ' ';
}
return;
}
#define SM_PATTERN (0x55AA55AA)
#define SM_INCR ((256 << 10) / sizeof(unsigned int)) /* 64K words */
extern unsigned int __buserr_count(void);
extern void __default_buserr_handler(void);
extern void __restore_buserr_handler(void);
/* Allow the user to provide his/her own defaults. */
unsigned int __sizemem_default;
unsigned int
__sizemem ()
{
volatile unsigned int *base;
volatile unsigned int *probe;
unsigned int baseorig;
unsigned int sr;
extern char end[];
char *endptr = (char *)&end;
int extra;
/* If the linker script provided a value for the memory size (or the user
overrode it in a debugger), use that. */
if (__sizemem_default)
return __sizemem_default;
/* If we are running in kernel segment 0 (possibly cached), try sizing memory
in kernel segment 1 (uncached) to avoid some problems with monitors. */
if (endptr >= K0BASE_ADDR && endptr < K1BASE_ADDR)
endptr = (endptr - K0BASE_ADDR) + K1BASE_ADDR;
INTDISABLE(sr,baseorig); /* disable all interrupt masks */
__default_buserr_handler();
__cpu_flush();
DOSYNC();
/* _end is the end of the user program. _end may not be properly aligned
for an int pointer, so we adjust the address to make sure it is safe.
We use void * arithmetic to avoid accidentally truncating the pointer. */
extra = ((int) endptr & (sizeof (int) - 1));
base = ((void *) endptr + sizeof (int) - extra);
baseorig = *base;
*base = SM_PATTERN;
/* This assumes that the instructions fetched between the store, and
the following read will have changed the data bus contents: */
if (*base == SM_PATTERN) {
probe = base;
for (;;) {
unsigned int probeorig;
probe += SM_INCR;
probeorig = *probe;
/* Check if a bus error occurred: */
if (!__buserr_count()) {
*probe = SM_PATTERN;
DOSYNC();
if (*probe == SM_PATTERN) {
*probe = ~SM_PATTERN;
DOSYNC();
if (*probe == ~SM_PATTERN) {
if (*base == SM_PATTERN) {
*probe = probeorig;
continue;
}
}
}
*probe = probeorig;
}
break;
}
}
*base = baseorig;
__restore_buserr_handler();
__cpu_flush();
DOSYNC();
INTRESTORE(sr); /* restore interrupt mask to entry state */
return((probe - base) * sizeof(unsigned int));
}
/* Provided as a function, so as to avoid reading the I/O location
multiple times: */
static int
convertbcd(byte)
unsigned char byte;
{
return ((((byte >> 4) & 0xF) * 10) + (byte & 0xF));
}
time_t
time (_timer)
time_t *_timer;
{
time_t result = 0;
struct tm tm;
*RTC_CONTROL |= RTC_CTL_LOCK_READ;
DOSYNC();
tm.tm_sec = convertbcd(*RTC_SECS);
tm.tm_min = convertbcd(*RTC_MINS);
tm.tm_hour = convertbcd(*RTC_HOURS);
tm.tm_mday = convertbcd(*RTC_DATE);
tm.tm_mon = convertbcd(*RTC_MONTH);
tm.tm_year = convertbcd(*RTC_YEAR);
DOSYNC();
*RTC_CONTROL &= ~(RTC_CTL_LOCK_READ | RTC_CTL_LOCK_WRITE);
tm.tm_isdst = 0;
/* Check for invalid time information */
if ((tm.tm_sec < 60) && (tm.tm_min < 60) && (tm.tm_hour < 24)
&& (tm.tm_mday < 32) && (tm.tm_mon < 13)) {
/* Get the correct year number, but keep it in YEAR-1900 form: */
if (tm.tm_year < 70)
tm.tm_year += 100;
#if 0 /* NOTE: mon_printf() can only accept 4 arguments (format string + 3 fields) */
mon_printf("[DBG: s=%d m=%d h=%d]", tm.tm_sec, tm.tm_min, tm.tm_hour);
mon_printf("[DBG: d=%d m=%d y=%d]", tm.tm_mday, tm.tm_mon, tm.tm_year);
#endif
/* Convert the time-structure into a second count */
result = mktime (&tm);
}
if (_timer != NULL)
*_timer = result;
return (result);
}
/*> EOF cma101.c <*/