circuitpython/zephyr/src/zephyr_getchar.c

65 lines
1.8 KiB
C

/*
* Copyright (c) 2016 Linaro
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <zephyr.h>
#include <uart.h>
#include <drivers/console/uart_console.h>
#include <misc/printk.h>
#include "zephyr_getchar.h"
extern int mp_interrupt_char;
void mp_keyboard_interrupt(void);
static struct nano_sem uart_sem;
#define UART_BUFSIZE 256
static uint8_t uart_ringbuf[UART_BUFSIZE];
static uint8_t i_get, i_put;
static int console_irq_input_hook(uint8_t ch)
{
int i_next = (i_put + 1) & (UART_BUFSIZE - 1);
if (i_next == i_get) {
printk("UART buffer overflow - char dropped\n");
return 1;
}
if (ch == mp_interrupt_char) {
mp_keyboard_interrupt();
return 1;
} else {
uart_ringbuf[i_put] = ch;
i_put = i_next;
}
//printk("%x\n", ch);
k_sem_give(&uart_sem);
return 1;
}
uint8_t zephyr_getchar(void) {
k_sem_take(&uart_sem, K_FOREVER);
unsigned int key = irq_lock();
uint8_t c = uart_ringbuf[i_get++];
i_get &= UART_BUFSIZE - 1;
irq_unlock(key);
return c;
}
void zephyr_getchar_init(void) {
k_sem_init(&uart_sem, 0, UINT_MAX);
uart_console_in_debug_hook_install(console_irq_input_hook);
// All NULLs because we're interested only in the callback above
uart_register_input(NULL, NULL, NULL);
}