112 lines
2.1 KiB
C
112 lines
2.1 KiB
C
/*
|
|
* vdprintf.c
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <stdarg.h>
|
|
#include <unistd.h>
|
|
#include <inttypes.h>
|
|
#include <sys/io.h>
|
|
#include <sys/cpu.h>
|
|
|
|
#ifdef DEBUG_PORT
|
|
|
|
#define BUFFER_SIZE 4096
|
|
|
|
enum serial_port_regs {
|
|
THR = 0,
|
|
RBR = 0,
|
|
DLL = 0,
|
|
DLM = 1,
|
|
IER = 1,
|
|
IIR = 2,
|
|
FCR = 2,
|
|
LCR = 3,
|
|
MCR = 4,
|
|
LSR = 5,
|
|
MSR = 6,
|
|
SCR = 7,
|
|
};
|
|
|
|
static const uint16_t debug_base = DEBUG_PORT;
|
|
|
|
static void debug_putc(char c)
|
|
{
|
|
if (c == '\n')
|
|
debug_putc('\r');
|
|
|
|
while ((inb(debug_base + LSR) & 0x20) == 0)
|
|
cpu_relax();
|
|
outb(c, debug_base + THR);
|
|
}
|
|
|
|
void vdprintf(const char *format, va_list ap)
|
|
{
|
|
int rv;
|
|
char buffer[BUFFER_SIZE];
|
|
char *p;
|
|
static bool debug_init = false;
|
|
static bool debug_ok = false;
|
|
|
|
rv = vsnprintf(buffer, BUFFER_SIZE, format, ap);
|
|
if (rv < 0)
|
|
return;
|
|
|
|
if (rv > BUFFER_SIZE - 1)
|
|
rv = BUFFER_SIZE - 1;
|
|
|
|
/*
|
|
* This unconditionally outputs to a serial port at 0x3f8 regardless of
|
|
* if one is enabled or not (this means we don't have to enable the real
|
|
* serial console and therefore get conflicting output.)
|
|
*/
|
|
if (__unlikely(!debug_init)) {
|
|
uint8_t dll, dlm, lcr;
|
|
|
|
debug_init = true;
|
|
|
|
cli();
|
|
|
|
/* Initialize the serial port to 115200 n81 with FIFOs enabled */
|
|
outb(0x83, debug_base + LCR);
|
|
outb(0x01, debug_base + DLL);
|
|
outb(0x00, debug_base + DLM);
|
|
(void)inb(debug_base + IER); /* Synchronize */
|
|
dll = inb(debug_base + DLL);
|
|
dlm = inb(debug_base + DLM);
|
|
lcr = inb(debug_base + LCR);
|
|
|
|
outb(0x03, debug_base + LCR);
|
|
(void)inb(debug_base + IER); /* Synchronize */
|
|
|
|
outb(0x00, debug_base + IER);
|
|
(void)inb(debug_base + IER); /* Synchronize */
|
|
|
|
sti();
|
|
|
|
if (dll != 0x01 || dlm != 0x00 || lcr != 0x83) {
|
|
/* No serial port present */
|
|
return;
|
|
}
|
|
|
|
outb(0x01, debug_base + FCR);
|
|
(void)inb(debug_base + IER); /* Synchronize */
|
|
if (inb(debug_base + IIR) < 0xc0) {
|
|
outb(0x00, debug_base + FCR); /* Disable non-functional FIFOs */
|
|
(void)inb(debug_base + IER); /* Synchronize */
|
|
}
|
|
|
|
debug_ok = true;
|
|
}
|
|
|
|
if (!debug_ok)
|
|
return;
|
|
|
|
p = buffer;
|
|
while (rv--)
|
|
debug_putc(*p++);
|
|
}
|
|
|
|
#endif /* DEBUG_PORT */
|