[RESEND,0/2] STM32 DMA alternative REQ/ACK protocol support

Message

Amelie Delaunay July 21, 2021, 11:39 a.m. UTC

Default REQ/ACK protocol consists in maintaining ACK signal up to the
removal of REQuest and the transfer completion.
In case of alternative REQ/ACK protocol, ACK de-assertion does not wait the
removal of the REQuest, but only the transfer completion.
Due to a possible DMA stream lock when transferring data to/from STM32
USART/UART, add support to select alternative REQ/ACK protocol.

Amelie Delaunay (2):
  dt-bindings: dma: add alternative REQ/ACK protocol selection in
    stm32-dma
  dmaengine: stm32-dma: add alternate REQ/ACK protocol management

 Documentation/devicetree/bindings/dma/st,stm32-dma.yaml | 7 +++++++
 drivers/dma/stm32-dma.c                                 | 8 ++++++--
 2 files changed, 13 insertions(+), 2 deletions(-)