Fix of Buffered Serial RX/TX crash problem on REALTEK_RTL8195am

[AdamZhang0124]

This PR addresses the issue of #8081.
It removes 'interrupt disable' in 'serial_loguart_irq_handler' function in "serial_api.c".

Description

1. Remove 'log_uart_irq_set' to avoid interrupt being untimely disabled in buffered serial mode.

Pull request type

[x] Fix
[ ] Refactor
[ ] Target update
[ ] Functionality change
[ ] Docs update
[ ] Test update
[ ] Breaking change

Reviewers

Release Notes

[ciarmcom]

@AdamZhang0124, thank you for your changes.
@samchuarm @ARMmbed/mbed-os-maintainers please review.

[SeppoTakalo]

This cannot be verified anymore.
RTL9196AM cannot be build against Mbed OS master.

[0xc0170]

Good point!

@AdamZhang0124 Are you planning to re-enable MCU_RTL8195A ? Without it, we can't even build this fix.

[AdamZhang0124]

Good point!

@AdamZhang0124 Are you planning to re-enable MCU_RTL8195A ? Without it, we can't even build this fix.

I didn't disable MCU_RTL8195A. Our target seems to be excluded after the release of 5.12 SHA-1: 63dd5cb, but we did not receive any notice about this before the release.
Is it because of the issue of IAR 8 library update #9206 ? But how come the IAR update issue would affect the ARM and GCC_ARM compilers?

[cmonr]

@deepikabhavnani @SeppoTakalo #9923 (comment)

[samchuarm]

Hi, Adam@Realtek is re-building the libraries for RTL8195AM to support IAR8. He'll submit a PR to the master with the updated libraries once it's done. This PR can only be processed until MCU_RTL8195A is re-enabled.

Some background info. Realtek did submit a PR to include updated libraries for IAR8 support via below PR but for some reason that was not finished and lost in the pond.
#5520

[cmonr]

@AdamZhang0124 @samchuarm Would there happen to be any updates to share?

[AdamZhang0124]

@AdamZhang0124 @samchuarm Would there happen to be any updates to share?

Hi @cmonr ,
The library update for IAR 8.32 has been made. We are now troubleshooting the "Sync_failed" issue which happens while running greentea test with the new library.
It would be very helpful if you happen to know some possible causes of this issue. Thanks.

[cmonr]

@AdamZhang0124 Do you have a full test log that could be used to debug the problem?

[AdamZhang0124]

@AdamZhang0124 Do you have a full test log that could be used to debug the problem?

Yes, this is the newest full test log that I ran yesterday for your reference.
IAR_GTtest_270319.txt

[cmonr]

@flit @brianesquilona Would y'all know of any way to help out here?

@AdamZhang0124 Is this only an IAR issue?

[flit]

What is the problem? I can't parse anything out of the log file…

[cmonr]

@flit @brianesquilona Sorry, I may have jumped the gun a bit.

@AdamZhang0124 It looks like the target is hard faulting after attempting to initialize

SDR Controller Init

Are you also aware that this is being printed? Is this normal?

RTL8195A[ToolChain Version: gcc version 4.8.3 (Realtek ASDK-4.8.3p1 Build 2003)

[studavekar]

The library update for IAR 8.32 has been made. We are now troubleshooting the "Sync_failed" issue which happens while running greentea test with the new library.

From the logs we see lot of hard faults Hard Fault Error!!! from bootloader bin probably

RTL8195A[HAL]: Hard Fault Error!!!!
[1553657736.89][CONN][RXD] 

RTL8195A[HAL]: R0 = 0xd6
[1553657736.89][CONN][RXD] 

RTL8195A[HAL]: R1 = 0x0
[1553657736.89][CONN][RXD] 

RTL8195A[HAL]: R2 = 0x1000507c
[1553657736.89][CONN][RXD] 

RTL8195A[HAL]: R3 = 0x0
[1553657736.89][CONN][RXD] 

@AdamZhang0124 can you please confirm if blinky is working with library update to IAR 8.32 ?

[AdamZhang0124]

Hi @studavekar ,
The blinky example is not working. It is able to be compiled by IAR 8.32, but after copying the binary file to the device, it results with "transfer timed out" error.
IAR_blinky.txt
FAIL.TXT

[0xc0170]

@AdamZhang0124 If you are still having issues, create a new issue.

This fix shall be closed until realtek MCU is reenabled (can be tested).

[AdamZhang0124]

@AdamZhang0124 If you are still having issues, create a new issue.

This fix shall be closed until realtek MCU is reenabled (can be tested).

Hi @0xc0170 , for your information, the issue #9206 that blocks the device from compiling is still in progress. Thanks!

[0xc0170]

I propose to close this PR and reopen with an update. Please do once this is unblocked.