目前属于预研阶段，在A53和M4F间进行通信时，需要测试各种情况，于是在测试Vring空间时，关掉A53的接收函数，A53应用程序仍在尝试通过 rpmsg 向 M4发送消息。 最终所有邮箱都被填满、A53应用程序无法再向M4发送 rpmsg 消息.
终端控制台中看到错误消息："Failed to send mailbox message．．．．尝试增加 MBOX_TX_QUEGE_LEN"
该错误消息来自内核，当我在不接收来自M4的ACK回复时，连续发送18条消息以上就会出现这个错误，但是我在内核的相关代码中发现，MBOX_TX_QUEGE_LEN的值被定义为20，这与我发送18条信息就导致该错误明显不对。
我从上面链接得到一些解答，但是Vring空间缓冲区设置为256是不是就没有意义了？因为MBOX_TXQUEGE_LEN限制了消息的数量，VRING_BUFFER的数量根本不可能达到上限。
同时我发现一个奇妙的方式，在我的rpmsg_char_simple.c代码中，关于159行的打印信息，当我注释掉159的printf()函数时，会出现"Failed to send mailbox message．．．．尝试增加 MBOX_TX_QUEGE_LEN"
错误信息，但是保留该打印信息，就能够正常输出，这是为什么呢？我怀疑是printf（）函数的延迟导致的，但是我尝试将printf()函数换成usleep（）在此处添加延迟，依然报错！只有在该while循环中保留该打印信息，才能够成功运行，而不会出现邮箱队列满的问题，希望能够告诉我原因!感谢
/*
* rpmsg_char_simple.c
*
* Simple Example application using rpmsg-char library
*
* Copyright (c) 2020 Texas Instruments Incorporated - https://www.ti.com
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of Texas Instruments Incorporated nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/select.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <stdint.h>
#include <stddef.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <time.h>
#include <stdbool.h>
#include <semaphore.h>
#include <linux/rpmsg.h>
#include <ti_rpmsg_char.h>
#define NUM_ITERATIONS 100
#define REMOTE_ENDPT 14
int send_msg(int fd, char *msg, int len)
{
// clock_t start, end;
// double t;
// start = clock();
int ret = 0;
ret = write(fd, msg, len);
if (ret < 0) {
perror("Can't write to rpmsg endpt device\n");
return -1;
}
// end = clock();
// t = ((double)(end - start) / CLOCKS_PER_SEC);
// printf("T = %f\n",t);
return ret;
}
int recv_msg(int fd, int len, char *reply_msg, int *reply_len)
{
int ret = 0;
// clock_t start, end;
// double t;
// start = clock();
/* Note: len should be max length of response expected */
ret = read(fd, reply_msg, len);
if (ret < 0) {
perror("Can't read from rpmsg endpt device\n");
return -1;
} else {
*reply_len = ret;
}
// end = clock();
// t = ((double)(end - start) / CLOCKS_PER_SEC);
// printf("T = %f\n",t);
return 0;
}
/* single thread communicating with a single endpoint */
int rpmsg_char_ping(int rproc_id, char *dev_name, int local_endpt, int remote_endpt,
int num_msgs)
{
int ret = 0;
int i = 0;
int packet_len;
char eptdev_name[32] = { 0 };
char packet_buf[512] = { 0 };
char *str = "hello worldaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa1234567a";
char str1[1024] = {0};
int data_len = strlen(str);
rpmsg_char_dev_t *rcdev;
int flags = 0;
clock_t start, end;
double t,num = 0;
/*
* Open the remote rpmsg device identified by dev_name and bind the
* device to a local end-point used for receiving messages from
* remote processor
*/
sprintf(eptdev_name, "rpmsg-char-%d-%d", rproc_id, getpid());
rcdev = rpmsg_char_open(rproc_id, dev_name, local_endpt, remote_endpt,
eptdev_name, flags);
if (!rcdev) {
perror("Can't create an endpoint device");
return -EPERM;
}
printf("Created endpt device %s, fd = %d port = %d\n", eptdev_name,
rcdev->fd, rcdev->endpt);
printf("Exchanging %d messages with rpmsg device ti.ipc4.ping-pong on rproc id %d ...\n\n",
num_msgs, rproc_id);
// start = clock();
for (i = 0; i < num_msgs; i++) {
/* memset(packet_buf, 0, sizeof(packet_buf));
sprintf(packet_buf, "hello there %d!", i);
packet_len = strlen(packet_buf);
printf("Sending message #%d: %s\n", i, packet_buf);
ret = send_msg(rcdev->fd, (char *)packet_buf, packet_len); */
sprintf(str1, "hello there %d,%s", i,str);
data_len = strlen(str1);
printf("sending messages #%d\n,",i);
char *block_ptr = str1;
int block_len = strlen(block_ptr);
do{
if(data_len < 496){
block_len = data_len;
}
memset(packet_buf, 0, sizeof(packet_buf));
memcpy(packet_buf,block_ptr,496);
packet_len = strlen(packet_buf);
start = clock();
ret = send_msg(rcdev->fd, (char *)packet_buf, packet_len);
end = clock();
t = ((double)(end - start)) / CLOCKS_PER_SEC * 1000000;
num += t;
printf("%s, len = %d\n", packet_buf,packet_len);
block_len = strlen(block_ptr);
if(block_len > 496)
block_ptr += 496;
if (ret < 0) {
printf("send_msg failed for iteration %d, ret = %d\n",i, ret);
goto out;
}
if (ret != packet_len) {
printf("bytes written does not match send request, ret = %d, packet_len = %d\n",
i, ret);
goto out;
}
}while(block_len > 496);
/* printf("Receiving message #%d: ", i);
do{
memset(packet_buf, 0, sizeof(packet_buf));
ret = recv_msg(rcdev->fd, 512, (char *)packet_buf, &packet_len);
if (ret < 0) {
printf("recv_msg failed for iteration %d, ret = %d\n", i, ret);
goto out;
}
printf("%s, len = %d\n", packet_buf,packet_len);
}while(packet_len == 496);*/
}
// end = clock();
// t = ((double)(end - start) / CLOCKS_PER_SEC) * 1000000;
printf("T1 = %f us\n",num);
num = 0;
for (i = 0; i < num_msgs; i++) {
//printf("Receiving message #%d: ", i);
do{
memset(packet_buf, 0, sizeof(packet_buf));
start = clock();
ret = recv_msg(rcdev->fd, 512, (char *)packet_buf, &packet_len);
end = clock();
t = ((double)(end - start)) / CLOCKS_PER_SEC * 1000000;
num += t;
if (ret < 0) {
printf("recv_msg failed for iteration %d, ret = %d\n", i, ret);
goto out;
}
//printf("%s, len = %d\n", packet_buf,packet_len);
}while(packet_len == 496);
}
// end = clock();
// t = ((double)(end - start) / CLOCKS_PER_SEC) * 1000000;
printf("T2 = %f us\n",num);
printf("\nCommunicated %d messages successfully on %s\n\n",
num_msgs, eptdev_name);
out:
ret = rpmsg_char_close(rcdev);
if (ret < 0)
perror("Can't delete the endpoint device\n");
return ret;
}
void usage()
{
printf("Usage: rpmsg_char_simple [-r <rproc_id>] [-n <num_msgs>] [-d \
<rpmsg_dev_name] [-p <remote_endpt] [-l <local_endpt] \n");
printf("\t\tDefaults: rproc_id: 0 num_msgs: %d rpmsg_dev_name: NULL remote_endpt: %d\n",
NUM_ITERATIONS, REMOTE_ENDPT);
}
int main(int argc, char *argv[])
{
int ret, status, c;
int rproc_id = 0;
int num_msgs = NUM_ITERATIONS;
int remote_endpt = REMOTE_ENDPT;
int local_endpt = RPMSG_ADDR_ANY;
char *dev_name = NULL;
while (1) {
c = getopt(argc, argv, "r:n:p:d:l:");
if (c == -1)
break;
switch (c) {
case 'r':
rproc_id = atoi(optarg);
break;
case 'n':
num_msgs = atoi(optarg);
break;
case 'p':
remote_endpt = atoi(optarg);
break;
case 'd':
dev_name = optarg;
break;
case 'l':
local_endpt = atoi(optarg);
break;
default:
usage();
exit(0);
}
}
if (rproc_id < 0 || rproc_id >= RPROC_ID_MAX) {
printf("Invalid rproc id %d, should be less than %d\n",
rproc_id, RPROC_ID_MAX);
usage();
return 1;
}
/* Use auto-detection for SoC */
ret = rpmsg_char_init(NULL);
if (ret) {
printf("rpmsg_char_init failed, ret = %d\n", ret);
return ret;
}
status = rpmsg_char_ping(rproc_id, dev_name, local_endpt, remote_endpt, num_msgs);
rpmsg_char_exit();
if (status < 0) {
printf("TEST STATUS: FAILED\n");
} else {
printf("TEST STATUS: PASSED\n");
}
return 0;
}
此致！
FengLang
