57 lines
1.3 KiB
C
57 lines
1.3 KiB
C
#include "serial.h"
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#include "io.h"
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#include "irq.h"
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#include "vga.h"
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#define PORT 0x3f8 /* COM1 */
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#define SERIAL_MAX_SPEED 115200
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/* The type of parity. */
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#define UART_NO_PARITY 0x00
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#define UART_ODD_PARITY 0x08
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#define UART_EVEN_PARITY 0x18
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/* The type of word length. */
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#define UART_5BITS_WORD 0x00
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#define UART_6BITS_WORD 0x01
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#define UART_7BITS_WORD 0x02
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#define UART_8BITS_WORD 0x03
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/* The type of the length of stop bit. */
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#define UART_1_STOP_BIT 0x00
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#define UART_2_STOP_BITS 0x04
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void serialSetup(int speed)
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{
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unsigned short div = SERIAL_MAX_SPEED / speed;
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outb(PORT + 1, 0x00); // Disable all interrupts
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outb(PORT + 3, 0x80); // Enable DLAB (set baud rate divisor)
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outb(PORT + 0, div & 0xFF); // Set divisor lo byte
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outb(PORT + 1, div >> 8); // Set divisor hi byte
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outb(PORT + 3,
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UART_NO_PARITY | UART_8BITS_WORD | UART_1_STOP_BIT); // 8 bits, no parity, one stop bit
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outb(PORT + 2, 0xC7); // Enable FIFO, clear them, with 14-byte threshold
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outb(PORT + 4, 0x0B); // IRQs enabled, RTS/DSR set
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irqSetRoutine(IRQ_COM1, serial_handler);
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}
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int isTransmitEmpty()
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{
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return (inb(PORT + 5) & 0x20);
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}
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void serialWrite(char a)
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{
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while (isTransmitEmpty() == 0)
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;
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outb(PORT, a);
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}
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void serialDoIrq(struct interrupt_frame *level)
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{
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(void)level;
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char c = inb(PORT);
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serialWrite(c);
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}
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