2022-08-11 19:28:10 -07:00

135 lines
4.1 KiB
C

/*
* This file is part of the Black Magic Debug project.
*
* MIT License
*
* Copyright (c) 2021 Koen De Vleeschauwer
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#include "general.h"
#include "platform.h"
#include <assert.h>
#include "cdcacm.h"
#include "rtt.h"
#include "rtt_if.h"
/*********************************************************************
*
* rtt terminal i/o
*
**********************************************************************
*/
/* usb uart receive buffer */
static char recv_buf[RTT_DOWN_BUF_SIZE];
static uint32_t recv_head = 0;
static uint32_t recv_tail = 0;
/* data from host to target: number of free bytes in usb receive buffer */
inline static uint32_t recv_bytes_free()
{
if (recv_tail <= recv_head)
return sizeof(recv_buf) - recv_head + recv_tail - 1;
else
return recv_tail - recv_head - 1;
}
/* data from host to target: true if not enough free buffer space and we need to close flow control */
inline static bool recv_set_nak()
{
assert(sizeof(recv_buf) > 2 * CDCACM_PACKET_SIZE);
return recv_bytes_free() < 2 * CDCACM_PACKET_SIZE;
}
/* usbuart_usb_out_cb is called when usb uart has received new data for target.
this routine has to be fast */
void usbuart_usb_out_cb(usbd_device *dev, uint8_t ep)
{
(void)dev;
(void)ep;
char usb_buf[CDCACM_PACKET_SIZE];
/* close flow control while processing packet */
usbd_ep_nak_set(usbdev, CDCACM_UART_ENDPOINT, 1);
const uint16_t len = usbd_ep_read_packet(usbdev, CDCACM_UART_ENDPOINT, usb_buf, CDCACM_PACKET_SIZE);
/* skip flag: drop packet if not enough free buffer space */
if (rtt_flag_skip && len > recv_bytes_free()) {
usbd_ep_nak_set(usbdev, CDCACM_UART_ENDPOINT, 0);
return;
}
/* copy data to recv_buf */
for (int i = 0; i < len; i++) {
uint32_t next_recv_head = (recv_head + 1) % sizeof(recv_buf);
if (next_recv_head == recv_tail)
break; /* overflow */
recv_buf[recv_head] = usb_buf[i];
recv_head = next_recv_head;
}
/* block flag: flow control closed if not enough free buffer space */
if (!(rtt_flag_block && recv_set_nak()))
usbd_ep_nak_set(usbdev, CDCACM_UART_ENDPOINT, 0);
return;
}
/* rtt host to target: read one character */
int32_t rtt_getchar()
{
int retval;
if (recv_head == recv_tail)
return -1;
retval = recv_buf[recv_tail];
recv_tail = (recv_tail + 1) % sizeof(recv_buf);
/* open flow control if enough free buffer space */
if (!recv_set_nak())
usbd_ep_nak_set(usbdev, CDCACM_UART_ENDPOINT, 0);
return retval;
}
/* rtt host to target: true if no characters available for reading */
bool rtt_nodata()
{
return recv_head == recv_tail;
}
/* rtt target to host: write string */
uint32_t rtt_write(const char *buf, uint32_t len)
{
if (len != 0 && usbdev && cdcacm_get_config() && cdcacm_get_dtr()) {
for (uint32_t p = 0; p < len; p += CDCACM_PACKET_SIZE) {
uint32_t plen = MIN(CDCACM_PACKET_SIZE, len - p);
while(usbd_ep_write_packet(usbdev, CDCACM_UART_ENDPOINT, buf + p, plen) <= 0);
}
/* flush 64-byte packet on full-speed */
if (CDCACM_PACKET_SIZE == 64 && (len % CDCACM_PACKET_SIZE) == 0)
while(usbd_ep_write_packet(usbdev, CDCACM_UART_ENDPOINT, NULL, 0) <= 0);
}
return len;
}