92 lines
2.1 KiB
C
92 lines
2.1 KiB
C
/* rtt_console.c - Console messages to a RAM buffer that is then read by
|
|
* the Segger J-Link debugger
|
|
*/
|
|
|
|
/*
|
|
* Copyright (c) 2016 Nordic Semiconductor ASA
|
|
*
|
|
* SPDX-License-Identifier: Apache-2.0
|
|
*/
|
|
|
|
|
|
#include <kernel.h>
|
|
#include <misc/printk.h>
|
|
#include <device.h>
|
|
#include <init.h>
|
|
#include <SEGGER_RTT.h>
|
|
|
|
extern void __printk_hook_install(int (*fn)(int));
|
|
extern void __stdout_hook_install(int (*fn)(int));
|
|
|
|
static bool host_present;
|
|
|
|
/** @brief Wait for fixed period.
|
|
*
|
|
*/
|
|
static void wait(void)
|
|
{
|
|
if (k_is_in_isr()) {
|
|
if (IS_ENABLED(CONFIG_RTT_TX_RETRY_IN_INTERRUPT)) {
|
|
k_busy_wait(1000*CONFIG_RTT_TX_RETRY_DELAY_MS);
|
|
}
|
|
} else {
|
|
k_sleep(CONFIG_RTT_TX_RETRY_DELAY_MS);
|
|
}
|
|
}
|
|
|
|
static int rtt_console_out(int character)
|
|
{
|
|
char c = (char)character;
|
|
unsigned int cnt;
|
|
int max_cnt = CONFIG_RTT_TX_RETRY_CNT;
|
|
|
|
do {
|
|
SEGGER_RTT_LOCK();
|
|
cnt = SEGGER_RTT_WriteNoLock(0, &c, 1);
|
|
SEGGER_RTT_UNLOCK();
|
|
|
|
/* There are two possible reasons for not writing any data to
|
|
* RTT:
|
|
* - The host is not connected and not reading the data.
|
|
* - The buffer got full and will be read by the host.
|
|
* These two situations are distinguished using the following
|
|
* algorithm:
|
|
* At the beginning, the module assumes that the host is active,
|
|
* so when no data is read, it busy waits and retries.
|
|
* If, after retrying, the host reads the data, the module
|
|
* assumes that the host is active. If it fails, the module
|
|
* assumes that the host is inactive and stores that
|
|
* information. On next call, only one attempt takes place.
|
|
* The host is marked as active if the attempt is successful.
|
|
*/
|
|
if (cnt) {
|
|
/* byte processed - host is present. */
|
|
host_present = true;
|
|
} else if (host_present) {
|
|
if (max_cnt) {
|
|
wait();
|
|
max_cnt--;
|
|
continue;
|
|
} else {
|
|
host_present = false;
|
|
}
|
|
}
|
|
|
|
break;
|
|
} while (1);
|
|
|
|
return character;
|
|
}
|
|
|
|
static int rtt_console_init(struct device *d)
|
|
{
|
|
ARG_UNUSED(d);
|
|
|
|
__printk_hook_install(rtt_console_out);
|
|
__stdout_hook_install(rtt_console_out);
|
|
|
|
return 0;
|
|
}
|
|
|
|
SYS_INIT(rtt_console_init, PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEFAULT);
|