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/** @file kbd.c
*
* @brief Keyboard handler implementation.
*
* @author Hanjie Wu (hanjiew)
* @bug No functional bugs.
*/
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <x86/asm.h>
#include <x86/interrupt_defines.h>
#include <x86/keyhelp.h>
#include <console.h>
#include <interrupt.h>
#include <kbd.h>
#include <paging.h>
#include <pv.h>
#include <sync.h>
#include <usermem.h>
/** a node in queue of threads requesting keyboard access */
typedef struct kbd_request_s {
thread_t* t;
queue_t node;
} kbd_request_t;
/** size of scancode ring buffer, a big buffer enough for someone pressing
* keyboard fast */
#define KH_RING_SIZE PAGE_SIZE
/** size of character ring buffer, a big buffer enough for someone pressing
* keyboard fast */
#define CHR_RING_SIZE PAGE_SIZE
/** maximum readline size */
#define MAX_READLINE (CHR_RING_SIZE - 1)
/** queue of threads requesting keyboard access */
static queue_t* inputs = NULL;
/** mutex for keyboard request queue */
static mutex_t kbd_request_lock = MUTEX_INIT;
/** signal for a thread leaving request queue */
static cv_t kbd_request_cv = CV_INIT;
/** mutex for new scancode input */
static mutex_t input_lock = MUTEX_INIT;
/** signal for new scancode input */
static cv_t input_cv = CV_INIT;
/** augchar buffer */
static unsigned char kh_ring[KH_RING_SIZE];
/** read pointer of augchar ring buffer */
static int kh_r_pos = 0;
/** write pointer of augchar ring buffer */
static int kh_w_pos = 0;
/** character ring buffer */
static char chr_ring[CHR_RING_SIZE];
/** read pointer of character ring buffer */
static int chr_r_pos = 0;
/** write pointer of character ring buffer */
static int chr_w_pos = 0;
/**
* @brief keyboard inturrupt handler
*/
void kbd_handler_real(stack_frame_t* f) {
unsigned char sc = inb(KEYBOARD_PORT);
pic_acknowledge(KBD_IRQ);
kh_type kh = process_scancode(sc);
if (pv_inject_irq(f, KEY_IDT_ENTRY, kh) == 0) {
return;
}
if (KH_HASDATA(kh) && KH_ISMAKE(kh)) {
int next_w_pos = (kh_w_pos + 1) % KH_RING_SIZE;
if (next_w_pos != kh_r_pos) {
kh_ring[kh_w_pos] = kh;
kh_w_pos = next_w_pos;
}
}
cv_signal(&input_cv);
}
/**
* @brief process scancode until a char is produced
* @return char produced
*/
static int sc_process();
/**
* @brief flush a line to user buffer
* @param len length of buffer
* @param buf buffer
* @return size of chars flushed, -1: buf invalid
*/
static int flush_line(int len, va_t buf);
int do_readline(int len, va_t buf) {
if (len < 0 || len > MAX_READLINE) {
return -1;
}
if (len == 0) {
return 0;
}
kbd_request_t req;
req.t = get_current();
/* wait until our turn */
mutex_lock(&kbd_request_lock);
queue_insert_tail(&inputs, &req.node);
while (inputs != &req.node) {
cv_wait(&kbd_request_cv, &kbd_request_lock);
}
mutex_unlock(&kbd_request_lock);
int should_flush = 0;
if (chr_r_pos != chr_w_pos) {
int i;
for (i = chr_r_pos; i != chr_w_pos; i = (i + 1) % CHR_RING_SIZE) {
if (chr_ring[i] == '\n') {
should_flush = 1;
break;
}
}
/* check if ring is full */
if (chr_r_pos == (chr_w_pos + 1) % CHR_RING_SIZE) {
should_flush = 1;
}
}
while (should_flush == 0) {
/* wait for more chars */
char c = sc_process();
if (c == '\b') {
if (chr_w_pos != chr_r_pos) {
putbyte(c);
chr_w_pos = (chr_w_pos + CHR_RING_SIZE - 1) % CHR_RING_SIZE;
}
} else {
chr_ring[chr_w_pos] = c;
chr_w_pos = (chr_w_pos + 1) % CHR_RING_SIZE;
putbyte(c);
should_flush =
(c == '\n') || (chr_r_pos == (chr_w_pos + 1) % CHR_RING_SIZE);
}
}
int result = flush_line(len, buf);
mutex_lock(&kbd_request_lock);
queue_detach(&inputs, &req.node);
cv_signal(&kbd_request_cv);
mutex_unlock(&kbd_request_lock);
return result;
}
int do_getchar() {
kbd_request_t req;
req.t = get_current();
mutex_lock(&kbd_request_lock);
queue_insert_tail(&inputs, &req.node);
while (inputs != &req.node) {
cv_wait(&kbd_request_cv, &kbd_request_lock);
}
mutex_unlock(&kbd_request_lock);
int result;
if (chr_r_pos != chr_w_pos) {
result = chr_ring[chr_r_pos];
chr_r_pos = (chr_r_pos + 1) % CHR_RING_SIZE;
} else {
result = sc_process();
}
mutex_lock(&kbd_request_lock);
queue_detach(&inputs, &req.node);
cv_signal(&kbd_request_cv);
mutex_unlock(&kbd_request_lock);
return result;
}
static int flush_line(int len, va_t buf) {
int size = 0, i;
for (i = chr_r_pos; i != chr_w_pos; i = (i + 1) % CHR_RING_SIZE) {
size++;
if (chr_ring[i] == '\n') {
break;
}
}
if (size > len) {
size = len;
}
int end_pos = (chr_r_pos + size) % CHR_RING_SIZE;
if (end_pos > chr_r_pos) {
if (copy_to_user(buf, size, &chr_ring[chr_r_pos]) != 0) {
return -1;
}
} else {
int size_1 = (CHR_RING_SIZE - chr_r_pos);
if (copy_to_user(buf, size_1, &chr_ring[chr_r_pos]) != 0) {
return -1;
}
if (copy_to_user(buf + size_1, end_pos, &chr_ring[0]) != 0) {
return -1;
}
}
chr_r_pos = end_pos;
return size;
}
static int sc_process() {
while (1) {
/* wait for more scancode */
mutex_lock(&input_lock);
while (kh_r_pos == kh_w_pos) {
cv_wait(&input_cv, &input_lock);
}
kh_type kh = kh_ring[kh_r_pos];
kh_r_pos = (kh_r_pos + 1) % KH_RING_SIZE;
mutex_unlock(&input_lock);
return KH_GETCHAR(kh);
}
}
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