J784S4XEVM: IPC Synchronization failure

Kowshika K

Part Number: J784S4XEVM

Tool/software:

I am implementing IPC communication between a Linux host and the MCU2_0 core using RPMessage. The goal is to trigger a radar configuration task on the MCU2_0 core upon receiving an IPC request from Linux, and then send a status flag back to Linux once the task completes.

I’m using a semaphore to synchronize the IPC request and task execution. However, I’m encountering a timeout issue on the Linux side, indicating a synchronization failure between the IPC request and the MCU’s response.

Why might this timeout occur, and how can I resolve it? Are there better synchronization mechanisms for this use case? Please suggest debugging steps or alternative approaches.

Doredla Sudheer Kumar
Takuma Fujiwara

4 months ago

0 Tarun Mukesh Puvvada 4 months ago

TI__Mastermind 49766 points

Hello,

Kowshika K said:
The goal is to trigger a radar configuration task on the MCU2_0 core upon receiving an IPC request from Linux, and then send a status flag back to Linux once the task completes.

May i know how you are sending the IPC request from Linux to MCU2_0 core?

Kowshika K said:
I’m using a semaphore to synchronize the IPC request and task execution. However, I’m encountering a timeout issue on the Linux side, indicating a synchronization failure between the IPC request and the MCU’s response.

On MCU2_0 what OS are you using ? Are you using IPC LLD driver on MCU2_ to sync the IPC request from linux ?

Regards

Tarun Mukesh

0 Kowshika K 4 months ago in reply to Tarun Mukesh Puvvada

Prodigy 100 points

Tarun Mukesh Puvvada said:
May i know how you are sending the IPC request from Linux to MCU2_0 core?

 int rpmsg_char_ping(int rproc_id, char *dev_name, unsigned int local_endpt, unsigned int remote_endpt,
 int num_msgs)
 {
 int ret = 0;
 int i = 0;
 int packet_len;
 char eptdev_name[64] = {0};
 char packet_buf[512] = {0};
 rpmsg_char_dev_t *rcdev;
 int flags = 0;
 struct timespec ts_current;
 struct timespec ts_end;
 
 /* Open the remote rpmsg device */
 sprintf(eptdev_name, "rpmsg-char-%d-%d", rproc_id, getpid());
 rcdev = rpmsg_char_open((enum rproc_id)rproc_id, dev_name, local_endpt, remote_endpt,
 eptdev_name, flags);
 if (!rcdev) {
 perror("Can't create an endpoint device");
 return -EPERM;
 }
 printf("Starting Radar Interface Test\n\n");
 printf("Created endpt device %s, fd = %d port = %d\n", eptdev_name,
 rcdev->fd, rcdev->endpt);
 
 printf("Exchanging %d messages with rpmsg device %s on rproc id %d ...\n\n",
 num_msgs, eptdev_name, rproc_id);
 
 for (i = 0; i < num_msgs; i++) {
 memset(packet_buf, 0, sizeof(packet_buf));
 sprintf(packet_buf, "Configure %d!", i);
 packet_len = strlen(packet_buf) + 1; // Include null terminator
 
 printf("Sending message #%d: %s\n", i, packet_buf);
 clock_gettime(CLOCK_MONOTONIC, &ts_current);
 
 ret = send_msg(rcdev->fd, packet_buf, packet_len);
 if (ret < 0) {
 printf("send_msg failed for iteration %d, ret = %d\n", i, ret);
 return ret;
 goto out;
 }
 if (ret != packet_len) {
 printf("bytes written does not match send request, ret = %d, packet_len = %d\n",
 ret, packet_len);
 goto out;
 }
 
 uint32_t flag;
 int reply_len;
 ret = recv_msg(rcdev->fd, &flag, &reply_len);
 clock_gettime(CLOCK_MONOTONIC, &ts_end);
 
 if (ret < 0) {
 printf("recv_msg failed for iteration %d, ret = %d\n", i, ret);
 goto out;
 }
 
 /* MODIFIED SECTION: Accept any non-zero flag as valid */
 if (reply_len != sizeof(flag) || flag == 0) {
 printf("Invalid flag received for iteration %d: flag=%u, len=%d\n",
 i, flag, reply_len);
 ret = -1;
 goto out;
 }
 
 printf("Received flag for message #%d: %u, round trip delay(usecs) = %ld\n",
 i, flag, (ts_end.tv_sec - ts_current.tv_sec) * 1000000 +
 (ts_end.tv_nsec - ts_current.tv_nsec) / 1000);
 }
 
 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");
 return ret;
 }

I am sending the ipc request as a message "Configure 0!" from linux to RTOS core which is highlighted above.
Tarun Mukesh Puvvada said:
On MCU2_0 what OS are you using ? Are you using IPC LLD driver on MCU2_ to sync the IPC request from linux ?
FreeRTOS.
Yes, the code uses the IPC Low-Level Driver (LLD) on MCU2_0 to handle inter-processor communication (IPC), 
including synchronization with Linux running on the A72 core (MPU1_0).

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J784S4XEVM: IPC Synchronization failure