diff options
Diffstat (limited to 'kernel/drivers/serial.c')
| -rw-r--r-- | kernel/drivers/serial.c | 42 |
1 files changed, 33 insertions, 9 deletions
diff --git a/kernel/drivers/serial.c b/kernel/drivers/serial.c index c6172a6..e56c91b 100644 --- a/kernel/drivers/serial.c +++ b/kernel/drivers/serial.c @@ -1,31 +1,55 @@ // MIT License, Copyright (c) 2020 Marvin Borner +#include <assert.h> #include <cpu.h> #include <def.h> #include <serial.h> #include <str.h> +#define PORT 0x3f8 + +PROTECTED static u8 serial_enabled = 0; + +CLEAR void serial_disable(void) +{ + outb(PORT + 4, 0x1e); // Enable loopback + serial_enabled = 0; +} + +CLEAR void serial_enable(void) +{ + outb(PORT + 4, 0x0f); + serial_enabled = 1; +} + CLEAR void serial_install(void) { - outb(0x3f8 + 1, 0x00); - outb(0x3f8 + 3, 0x80); - outb(0x3f8 + 0, 0x03); - outb(0x3f8 + 1, 0x00); - outb(0x3f8 + 3, 0x03); - outb(0x3f8 + 2, 0xC7); - outb(0x3f8 + 4, 0x0B); + outb(PORT + 1, 0x00); + outb(PORT + 3, 0x80); + outb(PORT + 0, 0x03); + outb(PORT + 1, 0x00); + outb(PORT + 3, 0x03); + outb(PORT + 2, 0xc7); + + // Test serial chip + outb(PORT + 4, 0x1e); // Enable loopback + outb(PORT + 0, 0xae); // Write + assert(inb(PORT + 0) == 0xae); // Verify receive } static int is_transmit_empty(void) { - return inb(0x3f8 + 5) & 0x20; + return inb(PORT + 5) & 0x20; } void serial_put(char ch) { + if (!serial_enabled) + return; + while (is_transmit_empty() == 0) ; - outb(0x3f8, (u8)ch); + outb(PORT, (u8)ch); } void serial_print(const char *data) |