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#include <asm/interrupt.h>
#include <asm/io.h>
#include <errno.h>
#include <kernel/con.h>
#include <kernel/sched.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 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);
static char present;
static char rxbuf[256];
static unsigned rxread, rxwrite;
static struct task_struct *waiting_task;
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, 0x06);
outb(RSLINEC, 0x03);
outb(RSMODEMC, 0x0B);
outb(RSINTEN, 0x01);
inb(RSDATA);
/* 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");
rxread = 0;
rxwrite = 1;
waiting_task = NULL;
present = 1;
}
ssize_t rsread(void *buf, size_t len) {
ssize_t n = len;
char *b = buf;
if(!present)
return -ENXIO;
if(len == 0)
return 0;
while(n--) {
/* check if the buffer's empty and if so, go to sleep */
cli();
if(rxread == rxwrite)
interruptible_sleep_on(&waiting_task);
/* check again to see if anything was read, or we were interrupted */
if(rxread == rxwrite) {
sti();
return -EINTR;
}
sti();
*b++ = rxbuf[rxread];
rxread = rxread + 1 % sizeof(rxbuf);
}
return len;
}
void rs_handler(void) {
if((inb(RSLINES) & 1) == 0)
return;
if(rxwrite == (rxread - 1 % sizeof(rxbuf)))
return;
rxbuf[rxwrite] = inb(RSDATA);
rxwrite = rxwrite + 1 % sizeof(rxbuf);
if(waiting_task != NULL) {
waiting_task->state = TSTATE_RUNNING;
waiting_task = NULL;
}
}
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