drivers: udc_dwc2: Disable endpoint while hibernated #87324
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When the endpoint is disabled while the core is hibernated, there are timeouts waiting for interrupts. It is not clear how the stack should behave when class and/or application wants to disable the endpoint while device is suspended. The problem was originally observed when the endpoints were disabled as a result of usbd_disable() call. Avoid the timeouts by modifying the backup values instead of the real registers (which are not accessible when hibernated). Split the 32-bit txf_set variable into two 16-bit variables (txf_set and pending_tx_flush) because maximum number of TxFIFO instances is 16. The txf_set variable is used as-is, while the pending_tx_flush is used to keep track of TxFIFOs that have to be flushed on hibernation exit. Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
Wait for PHY clock before triggering START task to ensure overlapped reset for PHY and DWC2 core. Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
OUT endpoint 0 cannot be disabled and therefore the only way to forcibly reclaim the buffer is to reset the core. The reset does not finish if PHY clock is not running, but just triggering the reset seems to be enough to be able to reclaim the buffer. Signed-off-by: Tomasz Moń <tomasz.mon@nordicsemi.no>
jfischer-no
approved these changes
Mar 24, 2025
anangl
approved these changes
Mar 24, 2025
bjarki-andreasen
approved these changes
Mar 24, 2025
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When the endpoint is disabled while the core is hibernated, there are timeouts waiting for interrupts. It is not clear how the stack should behave when class and/or application wants to disable the endpoint while device is suspended. The problem was originally observed when the endpoints were disabled as a result of usbd_disable() call.
Avoid the timeouts by modifying the backup values instead of the real registers (which are not accessible when hibernated).
Split the 32-bit txf_set variable into two 16-bit variables (txf_set and pending_tx_flush) because maximum number of TxFIFO instances is 16. The txf_set variable is used as-is, while the pending_tx_flush is used to keep track of TxFIFOs that have to be flushed on hibernation exit.