ae5200595c
The virt machine is a generic target, much like the arm virt machine. Intended to be simple to use and a good target to run large systems like linux on. At the moment simply support booting and simple uart and timer support.
82 lines
1.8 KiB
C
82 lines
1.8 KiB
C
/*
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* Copyright (c) 2018 Travis Geiselbrecht
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*
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* Use of this source code is governed by a MIT-style
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* license that can be found in the LICENSE file or at
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* https://opensource.org/licenses/MIT
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*/
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#include <lk/reg.h>
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#include <lk/trace.h>
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#include <lib/cbuf.h>
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#include <kernel/thread.h>
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#include <platform.h>
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#include <platform/interrupts.h>
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#include <platform/debug.h>
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#include <platform/virt.h>
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#include <sys/types.h>
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#include "platform_p.h"
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// simple 16550 driver for the emulated serial port on qemu riscv virt machine
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static volatile uint8_t *const uart_base = (uint8_t *)UART0_BASE;
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#define RXBUF_SIZE 128
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static char uart_rx_buf_data[RXBUF_SIZE];
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static cbuf_t uart_rx_buf;
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static inline uint8_t uart_read_8(size_t offset) {
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return uart_base[offset];
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}
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static inline void uart_write_8(size_t offset, uint8_t val) {
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uart_base[offset] = val;
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}
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static enum handler_return uart_irq_handler(void *arg) {
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unsigned char c;
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bool resched = false;
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while (uart_read_8(5) & (1<<0)) {
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c = uart_read_8(0);
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cbuf_write_char(&uart_rx_buf, c, false);
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resched = true;
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}
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return resched ? INT_RESCHEDULE : INT_NO_RESCHEDULE;
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}
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void uart_init(void) {
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/* finish uart init to get rx going */
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cbuf_initialize_etc(&uart_rx_buf, RXBUF_SIZE, uart_rx_buf_data);
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register_int_handler(IRQ_UART0, uart_irq_handler, NULL);
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uart_write_8(1, 0x1); // enable receive data available interrupt
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unmask_interrupt(IRQ_UART0);
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}
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void uart_putc(char c) {
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while ((uart_read_8(5) & (1<<6)) == 0)
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;
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uart_write_8(0, c);
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}
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int uart_getc(char *c, bool wait) {
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return cbuf_read_char(&uart_rx_buf, c, wait);
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}
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void platform_dputc(char c) {
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if (c == '\n')
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platform_dputc('\r');
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uart_putc(c);
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}
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int platform_dgetc(char *c, bool wait) {
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int ret = uart_getc(c, wait);
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return ret;
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}
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