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#include <asm/interrupt.h>
#include <asm/io.h>
#include <errno.h>
#include <kernel/con.h>
#include <kernel/sched.h>
#include <kernel/serial.h>
#include <kernel/tty.h>
#include <sys/types.h>
#include <unistd.h>
/* 115200 baud */
#define DIVISOR 1
#define RSBASE 0x3F8
#define RSDATA RSBASE
#define RSINTEN (RSBASE + 1)
#define RSFIFOC (RSBASE + 2)
#define RSINTID (RSBASE + 2)
#define RSLINEC (RSBASE + 3)
#define RSMODEMC (RSBASE + 4)
#define RSLINES (RSBASE + 5)
#define RSMODEMS (RSBASE + 6)
#define RSSCRATCH (RSBASE + 7)
#define rswait()\
while((inb(RSLINES) & 0x20) == 0);
extern void rs_isr(void);
/* internal function prototypes */
void rsint_tx(void);
struct tty_struct tty_rs = {
.init = &serial_init,
.write = &rsint_tx
};
static char present;
int rsputs(char *s) {
if(!present)
return -ENXIO;
while(*s) {
rswait();
if(*s == '\n' || *s == '\r') {
outb(RSDATA, '\n');
rswait();
outb(RSDATA, '\r');
s++;
} else {
outb(RSDATA, *s++);
}
}
return 0;
}
void serial_init(void) {
present = 0;
outb(RSSCRATCH, 0x00);
outb(RSSCRATCH, 0xAA);
if(inb(RSSCRATCH) != 0xAA) {
printk("[rs] COM0 not detected!\n");
return;
}
/* enable access to the divisor */
outb(RSLINEC, inb(RSLINEC) | 0x80);
/* write the divisor */
outb(RSBASE, DIVISOR);
outb(RSBASE + 1, DIVISOR >> 8);
/* restore access to the divisor */
outb(RSLINEC, inb(RSLINEC) & 0x7F);
/* configure port parameters */
outb(RSFIFOC, 0x07);
outb(RSLINEC, 0x03);
outb(RSMODEMC, 0x0B);
outb(RSINTEN, 0x03);
inb(RSDATA);
/* test FIFO functionality */
if(inb(RSINTID) & 0xC0 != 0xC0) {
printk("[rs] Failed to enable FIFO on COM0!\n");
return;
}
/* register the interrupt handler */
register_isr(0x24, 0, &rs_isr);
irq_enable(0x10);
rsputs("[kernel] Serial monitor initialized!\n\r");
printk("[rs] Serial port COM0 initialized!\n");
present = 1;
}
void rsint_rx(void) {
struct tty_queue *q = &tty_rs.rqueue;
if((inb(RSLINES) & 1) == 0)
return;
if(q->pwrite == (q->pread - 1 % sizeof(q->buf)))
return;
q->buf[q->pwrite] = inb(RSDATA);
q->pwrite = q->pwrite + 1 % sizeof(q->buf);
wake_up(&q->waiting);
}
void rsint_tx(void) {
int copied = 0;
struct tty_queue *q = &tty_rs.wqueue;
while(q->pread != q->pwrite) {
/* we're done if the TX FIFO is full */
if((inb(RSLINES) & 0x20) == 0)
break;
outb(RSDATA, q->buf[q->pread]);
q->pread = (q->pread + 1) % TTY_BUF_SIZE;
copied = 1;
}
if(copied)
wake_up(&q->waiting);
}
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