As already mentioned all USART drivers implemented for various platforms included in TF-M are not compliant with CMSIS USART Driver specification. They implement blocking send/receive and no power on/off.
Drivers should be rewritten and should pass the CMSIS Driver Validation.
| Status | Assigned | Task | ||
|---|---|---|---|---|
| Resolved | davidwang | T532 TF-M / CMSIS-Pack Alignment | ||
| Resolved | mingyangSun | T541 USART driver implementations for platforms included in TF-M |
Hi, @RobertRostohar
If we remove the "FILE _stdout" declaration from uart_stdout.c as mentioned(It prevents Clib mutex initialization), ARMCLANG image will not output anything anymore.
As the example shown in the link:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.100073_0613_00_en/chr1358938930615.html
"FILE _stdout" is needed for retargeting.
We do not have the same environment(CMSIS-Pack with MDK environment) to reproduce the output in your environment.
Wonder if you knew the root cause of why "FILE __stdout" prevents Clib mutex initialization?
It seems that we can reimplement low level I/O functions such as _sys_write() and _ttywrch(). In that way, we do not need to declare "FILE __stdio".
besides CMSIS USART driver compliant work, also remove printing with SVC together.
CMSIS compliant (relying on patches that remove SVC print):
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2489
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2955
remove printing with SVC:
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2933
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2934
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2935
https://review.trustedfirmware.org/c/trusted-firmware-m/+/2936