kernel/tty: poll only on IRQs, don't burn cycles

4 files changed, 15 insertions, 15 deletions

diff --git a/src/kernel/arch/i386/interrupts/irq.c b/src/kernel/arch/i386/interrupts/irq.c
index cb33bc8..7b8c166 100644
--- a/src/kernel/arch/i386/interrupts/irq.c
+++ b/src/kernel/arch/i386/interrupts/irq.c
@@ -5,27 +5,24 @@
 static const int PIC1 = 0x20;
 static const int PIC2 = 0xA0;
 
-static void irq_unmask(uint8_t line) {
-	uint16_t pic = line < 8 ? PIC1 : PIC2;
-	line &= 7;
-
-	port_out8(pic+1, port_in8(pic+1) & ~(1 << line));
-}
-
 void irq_init(void) {
-	port_out8(PIC1, 0x11);  /* start init sequence */
+	port_out8(PIC1, 0x11);   /* start init sequence */
 	port_out8(PIC2, 0x11);
 
-	port_out8(PIC1+1, 0x20);   /* interrupt offsets */
+	port_out8(PIC1+1, 0x20); /* interrupt offsets */
 	port_out8(PIC2+1, 0x30);
 
-	port_out8(PIC1+1, 0x4);   /* just look at the osdev wiki lol */
+	port_out8(PIC1+1, 0x4);  /* just look at the osdev wiki lol */
 	port_out8(PIC2+1, 0x2);
 
-	port_out8(PIC1+1, 0x1);   /* 8086 mode */
+	port_out8(PIC1+1, 0x1);  /* 8086 mode */
 	port_out8(PIC2+1, 0x1);
 
-	port_out8(PIC1+1, 0xfd); /* mask */
+	uint8_t mask = 0xff;
+	mask &= ~(1 << 1); // keyboard
+	mask &= ~(1 << 4); // COM1
+
+	port_out8(PIC1+1, mask);
 	port_out8(PIC2+1, 0xff);
 }
 
diff --git a/src/kernel/arch/i386/interrupts/isr.c b/src/kernel/arch/i386/interrupts/isr.c
index 1448f44..cc90fae 100644
--- a/src/kernel/arch/i386/interrupts/isr.c
+++ b/src/kernel/arch/i386/interrupts/isr.c
@@ -24,6 +24,10 @@ void isr_stage3(int interrupt) {
 			irq_eoi(1);
 			return;
 
+		case 0x24:; // COM1 irq
+			irq_eoi(1);
+			return;
+
 		default:
 			// TODO check if the exception was in the kernel
 			process_kill(process_current, interrupt);
diff --git a/src/kernel/arch/i386/tty/serial.c b/src/kernel/arch/i386/tty/serial.c
index e77ff5c..054f956 100644
--- a/src/kernel/arch/i386/tty/serial.c
+++ b/src/kernel/arch/i386/tty/serial.c
@@ -14,15 +14,13 @@ static void serial_selftest(void) {
 
 void serial_init(void) {
 	// see https://www.sci.muni.cz/docs/pc/serport.txt
-
-	port_out8(COM1 + 1, 0x00); // disable interrupts, we won't be using them
-
 	// set baud rate divisor
 	port_out8(COM1 + 3, 0b10000000); // enable DLAB
 	port_out8(COM1 + 0, 0x01);       // divisor = 1 (low  byte)
 	port_out8(COM1 + 1, 0x00);       //             (high byte)
 
 	port_out8(COM1 + 3, 0b00000011); // 8 bits, no parity, one stop bit
+	port_out8(COM1 + 1, 0x01);       // enable the Data Ready IRQ
 	port_out8(COM1 + 2, 0b11000111); // enable FIFO with 14-bit trigger level (???)
 
 	serial_selftest();
diff --git a/src/kernel/arch/i386/tty/tty.c b/src/kernel/arch/i386/tty/tty.c
index f3fecf3..a63c16a 100644
--- a/src/kernel/arch/i386/tty/tty.c
+++ b/src/kernel/arch/i386/tty/tty.c
@@ -19,6 +19,7 @@ void tty_read(char *buf, size_t len) {
 		for (;;) {
 			if (serial_poll_read(&buf[i]))		break;
 			if (keyboard_poll_read(&buf[i]))	break;
+			asm("hlt" ::: "memory");
 		}
 	}
 }