Mark
102 lines
2.3 KiB
C
102 lines
2.3 KiB
C
#include "arch/amd64/hw/rs232.h"
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#include "arch/amd64/hw/irq.h"
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#include "arch/amd64/hw/io.h"
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#include "sys/char/tty.h"
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#include "sys/assert.h"
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#include "sys/debug.h"
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#define RS232_DTR 0
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#define RS232_IER 1
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#define RS232_ISR 2
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#define RS232_LCR 3
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#define RS232_MCR 4
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#define RS232_LSR 5
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#define RS232_MSR 6
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#define RS232_SCR 7
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#define RS232_LCR_8B 0x3
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#define RS232_LCR_1SB 0
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#define RS232_LCR_PNON 0
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#define RS232_IER_RCE 1
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#define RS232_IER_BRE 4
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#define RS232_LSR_DR 1
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#define RS232_LSR_OE 2
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#define RS232_LSR_PE 4
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#define RS232_LSR_FE 8
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#define RS232_LSR_BI 16
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#define RS232_LSR_THRE 32
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#define RS232_LSR_TEMT 64
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#define RS232_LSR_ERR 128
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uint32_t rs232_avail = 0;
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static int tty_serial_putc(void *ctx, int ch) {
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rs232_send((uintptr_t) ctx, ch);
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return 0;
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}
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static struct tty_serial tty_com1 = {
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.ctx = (void *) RS232_COM1,
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.tty = NULL,
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.putc = tty_serial_putc
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};
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void rs232_send(uint16_t port, char c) {
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while (!(inb(port + RS232_LSR) & RS232_LSR_THRE)) {
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}
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outb(port, c);
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}
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static uint32_t rs232_irq(void *ctx) {
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uint16_t port = (uint16_t) (uintptr_t) ctx;
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int has_data = 0;
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uint8_t s;
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while ((s = inb(port + RS232_LSR)) & RS232_LSR_DR) {
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has_data = 1;
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uint8_t c = inb(port);
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if (port == RS232_COM1 && tty_com1.tty) {
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tty_data_write(tty_com1.tty, c);
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}
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}
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return has_data ? IRQ_HANDLED : IRQ_UNHANDLED;
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}
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void rs232_add_tty(int n) {
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// No other implemented yet
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_assert(n == 0);
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tty_create_serial(&tty_com1);
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}
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void rs232_init(uint16_t port) {
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// Disable interrupts
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outb(port + RS232_IER, 0x00);
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// Set divisor entry mode
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// Base frequency is 115200, so just enter 1
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outb(port + RS232_LCR, 0x80);
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outb(port + RS232_DTR, 0x00);
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outb(port + RS232_IER, 0x01);
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// Set line control: 8 bits, 1 stop bit, no parity control
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outb(port + RS232_LCR, RS232_LCR_8B | RS232_LCR_1SB | RS232_LCR_PNON);
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outb(port + RS232_ISR, 0xC7);
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// Enable receive interrupts
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outb(port + RS232_IER, RS232_IER_RCE);
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switch (port) {
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case RS232_COM1:
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rs232_avail |= (1 << 0);
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break;
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}
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irq_add_leg_handler(IRQ_LEG_COM1_3, rs232_irq, (void *) RS232_COM1);
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}
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