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#include <stdbool.h>
#include <stdlib.h>
#include <stdio.h>
#include <console.h>
#include <sys/io.h>
#include <sys/cpu.h>
#include <syslinux/config.h>
#include "serial.h"
enum {
THR = 0,
RBR = 0,
DLL = 0,
DLM = 1,
IER = 1,
IIR = 2,
FCR = 2,
LCR = 3,
MCR = 4,
LSR = 5,
MSR = 6,
SCR = 7,
};
int serial_init(struct serial_if *sif, const char *argv[])
{
const struct syslinux_serial_console_info *sci
= syslinux_serial_console_info();
uint16_t port;
unsigned int divisor;
uint8_t dll, dlm, lcr;
if (!argv[0]) {
if (sci->iobase) {
port = sci->iobase;
} else {
printf("No port number specified and not using serial console!\n");
return -1;
}
} else {
port = strtoul(argv[0], NULL, 0);
if (port <= 3) {
uint16_t addr = ((uint16_t *)0x400)[port];
if (!addr) {
printf("No serial port address found!\n");
return -1;
}
printf("Serial port %u is at 0x%04x\n", port, addr);
port = addr;
}
}
sif->port = port;
sif->console = false;
divisor = 1; /* Default speed = 115200 bps */
/* Check to see if this is the same as the serial console */
if (port == sci->iobase) {
/* Overlaying the console... */
sif->console = true;
/* Default to already configured speed */
divisor = sci->divisor;
/* Shut down I/O to the console for the time being */
openconsole(&dev_null_r, &dev_null_w);
}
if (argv[0] && argv[1])
divisor = 115200/strtoul(argv[1], NULL, 0);
cli(); /* Just in case... */
/* Save old register settings */
sif->old.lcr = inb(port + LCR);
sif->old.mcr = inb(port + MCR);
sif->old.iir = inb(port + IIR);
/* Set speed */
outb(0x83, port + LCR); /* Enable divisor access */
sif->old.dll = inb(port + DLL);
sif->old.dlm = inb(port + DLM);
outb(divisor, port + DLL);
outb(divisor >> 8, port + DLM);
(void)inb(port + IER); /* Synchronize */
dll = inb(port + DLL);
dlm = inb(port + DLM);
lcr = inb(port + LCR);
outb(0x03, port + LCR); /* Enable data access, n81 */
(void)inb(port + IER); /* Synchronize */
sif->old.ier = inb(port + IER);
/* Disable interrupts */
outb(0, port + IER);
sti();
if (dll != (uint8_t)divisor ||
dlm != (uint8_t)(divisor >> 8) ||
lcr != 0x83) {
serial_cleanup(sif);
printf("No serial port detected!\n");
return -1; /* This doesn't look like a serial port */
}
/* Enable 16550A FIFOs if available */
outb(0x01, port + FCR); /* Enable FIFO */
(void)inb(port + IER); /* Synchronize */
if (inb(port + IIR) < 0xc0)
outb(0x00, port + FCR); /* Disable FIFOs if non-functional */
(void)inb(port + IER); /* Synchronize */
return 0;
}
void serial_write(struct serial_if *sif, const void *data, size_t n)
{
uint16_t port = sif->port;
const char *p = data;
uint8_t lsr;
while (n--) {
do {
lsr = inb(port + LSR);
} while (!(lsr & 0x20));
outb(*p++, port + THR);
}
}
void serial_read(struct serial_if *sif, void *data, size_t n)
{
uint16_t port = sif->port;
char *p = data;
uint8_t lsr;
while (n--) {
do {
lsr = inb(port + LSR);
} while (!(lsr & 0x01));
*p++ = inb(port + RBR);
}
}
void serial_cleanup(struct serial_if *sif)
{
uint16_t port = sif->port;
outb(0x83, port + LCR);
(void)inb(port + IER);
outb(sif->old.dll, port + DLL);
outb(sif->old.dlm, port + DLM);
(void)inb(port + IER);
outb(sif->old.lcr & 0x7f, port + LCR);
(void)inb(port + IER);
outb(sif->old.mcr, port + MCR);
outb(sif->old.ier, port + IER);
if (sif->old.iir < 0xc0)
outb(0x00, port + FCR); /* Disable FIFOs */
/* Re-enable console messages, if we shut them down */
if (sif->console)
openconsole(&dev_null_r, &dev_stdcon_w);
}
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