drivers: serial: nrfx_uarte: bugfixing and refactor #100177
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To pass the test with chopped TX data a dedicated TIMER for byte counting need to be used. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
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Remove parts of implementation which are no longer in use. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
Interrupt handler was handling events in a following order: ENDRX, RXSTARTED, RXTO. This could lead to error if RX buffer is short then with high baudrate RXSTARTED for the current buffer could be handled together with ENDRX and in that case uart_rx_buf_rsp called from RXSTARTED would return error as reception is already finished due to handled ENDRX. Reworking the driver to change that order to RXSTARTED, ENDRX, RXTO. Additionally, driver is optimize to only check HW events for enabled interrupts. To achieve that, RX path interrupts are all disabled then RX is disabled. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
Extend test to run a scenario where receiver is continuously providing 1 byte buffers and tries to receive loselessly data to that short buffers. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
Add pull-ups to all pins when in sleep state. Otherwise, those pins are floating and can lead to test failures. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
RX pin must have pull-up like in other boards. It is needed because 2 UART instances are connected and order of initialization is unknown so if receiver is initialized before the transmitter then RX pin may float and it can result in the unexpected receiver error. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
For few samples that used cellular modem on nrf9160dk a UART driver feature was enabled to use TIMER peripheral for byte counting. It used to be required to reliably received data even with HWFC. Since some time default receiver has been changed and UART wit HWFC is able to reliably receive data without need of using TIMER and PPI for byte counting. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
Some time ago a receiver mode for newer SoCs was introduced. It is using TIMER to count RX bytes via PPI. Due to changes in the system behavior it is not the same implementation as the one used on legacy targets (nRF52x, nRF53x and nRF91x). New implementation is using the Device Tree to assign a TIMER instance and old feature was using Kconfig which is now obsolete and error prone since it is easy to get resource usage conflict is some instances are managed in Device Tree and some in Kconfig. As a result to reliably receive data without HWFC user had to use different configuration depending on the target. Legacy implementation was using nrfx_timer and new one used HAL. Patch attempts to align better those two similar but different implementations by: - deprecating Kconfig symbols for selecting TIMER instance in favor of the Device Tree - extracting common part like PPI initialization and some control block fields - Using TIMER HAL in both implementations. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
Aligning configurations for Nordic targets after changes in the driver. CONFIG_UART_x_NRF_HW_ASYNC_TIMER option is deprecated. Where valid Device Tree configuration is added. Signed-off-by: Krzysztof Chruściński <krzysztof.chruscinski@nordicsemi.no>
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@nordic-krch is there any downsides of using timer node in DT even when HWFC is used? I'm thinking if this is easier to document/implement on some use-cases, or even allow runtime switching of FC? |
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@SeppoTakalo using TIMER on legacy SoCs like nRF91 is mainly resources cost (TIMER instance + DPPI channel). In terms of performance it is similar. |
bjarki-andreasen
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SeppoTakalo
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The order of handling RX events in the interrupt was forced to ENDRX, RXSTARTED, RXTO. It was working ok as long as buffers were not too short (compared to the baudrate) as this order assumed that RXSTARTED event is for the next buffer and that previous RXSTARTED is already handled.
When buffer is short (e.g. 1 byte) then ENDRX and RXSTARTED will cause an error as next buffer cannot be provided on time. It is better to enforce RXSTARTED, ENDRX, RXTO order. Driver is reworked. Additionally, RX interrupt sources are only enabled when RX is enabled. This approach allows to reduce number of register accesses in the interrupt handler.
Extended test to run a configuration where continuous reception happens to 1 byte buffers. Test is failing without the fix.
Complexity in the driver make it hard to apply the fix so driver is refactored. Complexity results from driver implementing 3 UART APIs and 4 receive modes for the asynchronous API:
Option 1 is removed and "ENHANCED RX" becomes the default so
CONFIG_UART_NRFX_UARTE_ENHANCED_RXis deprecated.Option 3 and 4 are aligned. Kconfig configuration for option 3 is deprecated and DT configuration is used like for option 4. To enable reliable reception without HWFC a
timernode need to be added to the uart node.