Virtual UART data send M4 to A7 wrong data

[SMich.1]

call every 40mS :

static uint32_t count;

VIRT_UART_Transmit(cameraCommHandle.huart,(uint8_t *)&count,sizeof(count));

OPENAMP_check_for_message();

count++;

when i printing what i get in linux i got this:

39.99 ms: 262

40.00 ms: 263

40.01 ms: 264

40.00 ms: 265

40.00 ms: 266

39.99 ms: 267

40.00 ms: 268

40.01 ms: 266

40.00 ms: 270

40.00 ms: 271

39.99 ms: 272

40.00 ms: 1

40.01 ms: 274

40.00 ms: 1

40.00 ms: 276

39.99 ms: 277

40.00 ms: 278

and it repeat itself every 256 counts

i attached the c program that reads the serial and prints the what in UARt.

[SMich.1]

one more test that i did : its prints 8bit counter with string and 16 bit of dummy.

root@stm32mp1-ground4-mx:/usr/csr/bin# ./read_trigger

971.24 ms: (104) 4 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.95 ms: (208) 5 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.96 ms: (312) 6 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.08 ms: (416) 7 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.91 ms: (520) 8 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.04 ms: (624) 9 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.96 ms: (728) 10 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.05 ms: (832) 11 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.96 ms: (936) 12 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.01 ms: (1040) 10 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.03 ms: (1144) 14 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.98 ms: (1248) 15 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.97 ms: (1352) 16 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

read 103 bytes instead of 104

500.04 ms: (1455) 97 0 - bcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.97 ms: (1559) 18 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

read 103 bytes instead of 104

500.02 ms: (1662) 97 0 - bcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

499.96 ms: (1766) 20 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

500.05 ms: (1870) 21 0 - abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrst

[Olivier GALLIEN]

Hi @SMich.1​ 

This is some hint I received from expert.

In your code it could be worth to add a check that "rien==4 " to confirm success of read().

Also you can start to implement with further trace using the dynamic debug framework :

echo -n 'file virtio_rpmsg_bus.c +p' > /sys/kernel/debug/dynamic_debug/control

You will get a trace for all messages received by A7, helping to narrowing down where the issue may come from

Hope it help,

Olivier

[SMich.1 · Accepted solution]

Hi, the issue was at the flags config. one of the flag was that to take the bytes as console.

[Olivier GALLIEN]

Hi @SMich.1​ 

Good news !

For reference could you please details further which flag you are talking about ?

Thx

Olivier