feat(keyboard): implement generic ring buffer and add getkey

Signed-off-by: Julien CLEMENT <julien.clement@epita.fr>

k/Makefile

@@ -35,7 +35,8 @@ OBJS	= \
 	  events/idt.o \
 	  events/isr.o \
 	  events/pic/pic.o \
-	  events/pic/keyboard.o
+	  events/pic/keyboard.o \
+	  utils/ring_buffer.o
 
 
 DEPS = $(OBJS:.o=.d)

k/events/pic/keyboard.c

@@ -1,7 +1,26 @@
 #include "keyboard.h"
 #include "io.h"
+#include "utils/ring_buffer.h"
+
+static struct ring_buffer keyboard_buffer;
 
 void keyboard_handler(void)
 {
-    inb(KEYBOARD_IO);
+    u8 scan_code = inb(KEYBOARD_IO);
+    if (!(scan_code & 0x80))
+        ring_buffer_push(&keyboard_buffer, &scan_code);
+}
+
+int getkey(void)
+{
+    u8 *key = ring_buffer_pop(&keyboard_buffer);
+    if (!key)
+        return -1;
+
+    return *key;
+}
+
+void init_keyboard(void)
+{
+    ring_buffer_init(&keyboard_buffer, sizeof(u8));
 }

k/events/pic/keyboard.h

@@ -6,4 +6,8 @@
 
 void keyboard_handler(void);
 
+int getkey(void);
+
+void init_keyboard(void);
+
 #endif /* !KEYBOARD_H */

k/events/pic/pic.c

@@ -2,6 +2,7 @@
 #include "io.h"
 #include "pic.h"
 #include "stdio.h"
+#include "keyboard.h"
 
 static void send_icw1(void)
 {
@@ -41,12 +42,12 @@ void init_pic(void)
     send_icw3();
     send_icw4();
     mask_irqs();
+    init_keyboard();
     asm volatile("sti");
 }
 
 void acknowledge(uint32_t int_vector)
 {
-    printf("acknowledging %d\r\n", int_vector);
     uint8_t ocw2 = 0x20;
     if (int_vector >= IDT_RESERVED_ENTRIES + 8)
         outb(SLAVE_PIC_A, ocw2);

k/utils/ring_buffer.c

@@ -0,0 +1,33 @@
+#include "ring_buffer.h"
+#include "string.h"
+
+void ring_buffer_init(struct ring_buffer *buffer, u32 el_size)
+{
+    buffer->start = 0;
+    buffer->end = 0;
+    buffer->element_size = el_size;
+    buffer->size = 0;
+}
+
+void ring_buffer_push(struct ring_buffer *buffer, void *el)
+{
+    if (buffer->size >= RING_BUFFER_SIZE)
+        return;
+
+    char *dst = buffer->buffer + buffer->start;
+    memcpy(dst, el, buffer->element_size);
+    buffer->start = (buffer->start + buffer->element_size) % RING_BUFFER_SIZE;
+    buffer->size += buffer->element_size;
+}
+
+void *ring_buffer_pop(struct ring_buffer *buffer)
+{
+    if (buffer->size == 0)
+        return NULL;
+
+    void *res = buffer->buffer + buffer->end;
+    buffer->end = (buffer->end + buffer->element_size) % RING_BUFFER_SIZE;
+    buffer->size -= buffer->element_size;
+
+    return res;
+}

k/utils/ring_buffer.h

@@ -0,0 +1,21 @@
+#ifndef RING_BUFFER_H
+#define RING_BUFFER_H
+
+#define RING_BUFFER_SIZE 256
+
+#include "k/types.h"
+
+struct ring_buffer
+{
+    char buffer[RING_BUFFER_SIZE];
+    u32 start;
+    u32 end;
+    u32 element_size;
+    u32 size;
+};
+
+void ring_buffer_init(struct ring_buffer *buffer, u32 el_size);
+void ring_buffer_push(struct ring_buffer *buffer, void *el);
+void *ring_buffer_pop(struct ring_buffer *buffer);
+
+#endif /* !RING_BUFFER_H */

k/utils/utils.h

@@ -0,0 +1,9 @@
+#ifndef UTILS_H
+#define UTILS_H
+
+static void *cast(void *ptr)
+{
+    return ptr;
+}
+
+#endif /* !UTILS_H */