[v2,00/10] serial: 8250: dw: RZN1 DMA support

Message

Miquel Raynal March 17, 2022, 5:46 p.m. UTC

Hello,

Support for the RZN1 DMA engine allows us adapt a little bit the 8250 DW
UART driver with to bring DMA support for this SoC.

This short series applies on top of the series bringing RZN1 DMA
support, currently on its v5, see [1]. Technically speaking, only the DT
patch needs to be applied after [1]. The other patches can come in at
any moment, because if no "dmas" property is provided in the DT, DMA
support will simply be ignored.

[1] https://lore.kernel.org/dmaengine/[e-mail]/T/#m0ef3323abce3eec961e142bf2fb35e95b9045fc5

Thanks,
Miquèl

Changes in v2:
* Rebased on top of Emil's patches. Added platform data structures
  instead of raw quirk integers in order to provide a CPR value.
* Added includes in dwlib.h even though it's not particularly useful, it
  may help preventing a build error later on if we ever decide to include
  this file from another location.
* Dropped the call to ->tx_dma and instead implemented a callback that
  can be called from serial8250_tx/rx_dma.
* Used the device API instead of the of API.
* Changed the logic about DMA capabilities to avoid breaking existing
  designs.
* Introduced a new quirk related to the flow-control feature of the
  RZ/N1 version of the UART controller when used with DMA.
* Re-arranged the entire series as advised by Andy and Geert.
* Added several preparation patches to ease the review of various
  functional changes.

Miquel Raynal (6):
  serial: 8250: dw: Use the device API
  serial: 8250: dw: Create a more generic platform data structure
  serial: 8250: dw: Check when possible if DMA is effectively supported
  serial: 8250: dma: Allow driver operations before starting DMA
    transfers
  serial: 8250: dw: Introduce an rx_timeout variable in the IRQ path
  ARM: dts: r9a06g032: Fill the UART DMA properties

Phil Edworthy (4):
  serial: 8250: dw: Move the per-device structure
  serial: 8250: dw: Allow to use a fallback CPR value if not synthesized
  serial: 8250: dw: Add support for DMA flow controlling devices
  serial: 8250: dw: Improve RZN1 support

 arch/arm/boot/dts/r9a06g032.dtsi     |  15 ++++
 drivers/tty/serial/8250/8250.h       |  18 +++++
 drivers/tty/serial/8250/8250_dma.c   |   4 +
 drivers/tty/serial/8250/8250_dw.c    | 116 +++++++++++++++++++++------
 drivers/tty/serial/8250/8250_dwlib.c |  11 ++-
 drivers/tty/serial/8250/8250_dwlib.h |  26 ++++++
 6 files changed, 163 insertions(+), 27 deletions(-)