STM32: Fix usart irq index

[bcostm]

Description

• There was an issue with the serial irq index used in the STM32 serial api implementation. On some platforms the indexes was wrong and this results to wrong usart access.
• The issue has been flagged in STM32L0 wrong UART interrupt index #5916 and STM serial_init change broke STM target interrupts #5931
• A fix has been found by @marcemmers (thanks again!) and done for STM32L0 devices in PR STM32L0: fix uart irq index #5917. But this PR has been closed due to this one covering all STM32 devices.

Status

READY

Migrations

NO

Todos

• Tests

@marcemmers can you please test it in your application for the STM32L0 ?

[0xc0170]

what happens if uart_name is out of defined BASES ? I can see that get uart index returns -1 if not there, but this is not handled here, can it happen?

[bcostm]

If we have well written all the usarts available in the device it should not happen... Before this it was worse because in some case we could access out of the arrays (uart_handlers[id] and serial_irq_ids[id]).

[bcostm]

An assert has been added in commit b6efdd5 to check this index.

[marcemmers]

I was wondering if the target necessary defines were still necessary? Haven't looked at the specific processor yet.

[bcostm]

yes it is required because the IRQ vector name is different and also the __HAL_GET_PENDING_IT macro is available only on F09x devices

[marcemmers]

I will test on the L073, will let you know what i find.

[marcemmers]

This worked fine for me on the L073RZ-Nucleo. Have tested all available uarts both on 9600 and 115k.

Did notice this however:

// Warning: the list of UART/USART in this function must be aligned with the list
// written in serial_init function.
int8_t get_uart_index(UARTName uart_name)

Why not remove the increment numbering from serial_init and also use get_uart_index instead? So:

#if defined(USART1_BASE)
    if (obj_s->uart == UART_1) {
        __HAL_RCC_USART1_FORCE_RESET();
        __HAL_RCC_USART1_RELEASE_RESET();
        __HAL_RCC_USART1_CLK_ENABLE();
    }
#endif

    obj_s->index = get_uart_index(obj_s->uart);    
    MBED_ASSERT(obj_s->index >= 0);

instead of

#if defined(USART1_BASE)
    if (obj_s->uart == UART_1) {
        __HAL_RCC_USART1_FORCE_RESET();
        __HAL_RCC_USART1_RELEASE_RESET();
        __HAL_RCC_USART1_CLK_ENABLE();
        obj_s->index = IndexNumber;
    }
    IndexNumber++;
#endif

[bcostm]

Yep I think you're right and it should work. It's even better that way ! 👍

I'll send a new commit with your proposal.

And the assert adresses this remark:

what happens if uart_name is out of defined BASES ? I can see that get uart index returns -1 if not there, but this is not handled here, can it happen?

[0xc0170]

@bcostm Please check travis failures

[bcostm]

Should be ok now with commit eb4b339

[0xc0170]

/morph build

[mbed-ci]

Build : SUCCESS

Build number : 1009
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/5962/

Triggering tests

/morph test
/morph uvisor-test
/morph export-build

[mbed-ci]

Exporter Build : SUCCESS

Build number : 700
Build artifacts/logs : http://mbed-os.s3-website-eu-west-1.amazonaws.com/?prefix=builds/exporter/5962/

[mbed-ci]

Test : SUCCESS

Build number : 824
Test logs :http://mbed-os-logs.s3-website-us-west-1.amazonaws.com/?prefix=logs/5962/824

[0xc0170]

/morph uvisor-test