Updated pic init

2021-08-22 19:59:55 +02:00
parent 6b0f6ddfb7
commit ad023a8119
5 changed files with 76 additions and 88 deletions
--- a/kernel/cpu/pic.c
+++ b/kernel/cpu/pic.c
@@ -0,0 +1,43 @@
+//
+// Created by rick on 22-08-21.
+//
+#include <myke/cpu/pic.h>
+#include <myke/drivers/ports.h>
+
+// https://wiki.osdev.org/8259_PIC
+#define ICW1_ICW4       0x01        /* ICW4 (not) needed */
+#define ICW1_SINGLE     0x02        /* Single (cascade) mode */
+#define ICW1_INTERVAL4  0x04        /* Call address interval 4 (8) */
+#define ICW1_LEVEL      0x08        /* Level triggered (edge) mode */
+#define ICW1_INIT       0x10        /* Initialization - required! */
+
+#define ICW4_8086       0x01        /* 8086/88 (MCS-80/85) mode */
+#define ICW4_AUTO       0x02        /* Auto (normal) EOI */
+#define ICW4_BUF_SLAVE  0x08        /* Buffered mode/slave */
+#define ICW4_BUF_MASTER 0x0C        /* Buffered mode/master */
+#define ICW4_SFNM       0x10        /* Special fully nested (not) */
+
+void pic_init() {
+    // init both master and slave pic's
+    port_byte_out(PORT_PIC_MASTER_COMMAND, ICW1_INIT | ICW1_ICW4);
+    port_byte_out(PORT_PIC_SLAVE_COMMAND, ICW1_INIT | ICW1_ICW4);
+
+    // master with ICW4 offset 20, Slave on IRQ2, 8086 mode,
+    // ICW2
+    port_byte_out(PORT_PIC_MASTER_DATA, 0x20); // offset master
+    port_byte_out(PORT_PIC_SLAVE_DATA, 0x28); // offset slave
+    // ICW3
+    port_byte_out(PORT_PIC_MASTER_DATA, 0x04); // slave PIC at IRQ2
+    port_byte_out(PORT_PIC_SLAVE_DATA, 0x02); // cascade identity
+    // ICW4
+    port_byte_out(PORT_PIC_MASTER_DATA, ICW4_8086); // 8086 mode
+    port_byte_out(PORT_PIC_SLAVE_DATA, ICW4_8086);
+
+    // empty mask
+    pic_set_mask(0);
+}
+
+void pic_set_mask(uint16_t mask) {
+    port_byte_out(PORT_PIC_MASTER_DATA, mask & 0xFF);
+    port_byte_out(PORT_PIC_SLAVE_DATA, mask << 8);
+}