Missing hw-flow-control; in hci_uart overlay files

[koffes]

Describe the bug
I attempted to get HW flow control working on the nRF5340.
hw-flow-control is missing in the overlay of some boards in https://github.com/zephyrproject-rtos/zephyr/tree/master/samples/bluetooth/hci_uart/boards

1. https://github.com/zephyrproject-rtos/zephyr/blob/master/samples/bluetooth/hci_uart/boards/nrf5340pdk_nrf5340_cpuapp.overlay has this enabled, but on the APP core instead of NET.
2. The nRF5340 DK should be added in addition to the PDK

As a general question. Why is not hw-flow-control enabled by default on more boards and simply deactivated using CONFIG_UART_LINE_CTRL=n ?

Impact
UART with flow control cannot be used for hci_uart on some boards.

[nordic-krch]

so nrf5340pdk_nrf5340_cpuapp configuration does not make sense. It should be nrf5340pdk_nrf5340_cpunet.

[nordic-krch]

fyi @carlescufi

[carlescufi]

so nrf5340pdk_nrf5340_cpuapp configuration does not make sense. It should be nrf5340pdk_nrf5340_cpunet.

Yes it does make sense, unless I'm mistaken. The net CPU runs the controller but the main app CPU runs the hci_uart main.c, right @joerchan ?

[carlescufi]

Agree that we are missing the overlay for the DK (we only have it for the PDK).

[joerchan]

Haven't tested this combination yet. Is this with hci-uart on the application core and then hci-rpmsg on network core then?

[koffes]

This particular issue was with APP core idle and hci-uart on NET. I.e. the host running on a PC.

[github-actions]

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[koffes]

Stale label should be removed.

[carlescufi]

@anangl and @nordic-krch could you please weigh in here?

[carlescufi]

This particular issue was with APP core idle and hci-uart on NET. I.e. the host running on a PC.

OK, then we will fix this particular case.