[PATCH v2 0/9] STM32 DMA3 updates for STM32MP25

[Amelie Delaunay]

The HW version of STM32 DMA3 inside STM32MP25 requires some tunings to
meet the needs of the interconnect. This series adds the linked list
refactoring feature to have optimal performance when addressing the
memory, and it adds the use of two new bits in the third cell specifying
the DMA transfer requirements:
- bit[16] to prevent packing/unpacking mode to avoid bytes loss in case
of interrupting an ongoing transfer (e.g. UART RX),
- bit[17] to prevent linked-list refactoring because some peripherals
(e.g. FMC ECC) require a one-shot transfer, they trigger the DMA only
once.
It also adds platform data to clamp the burst length on AXI port,
especially when it is interconnected to AXI3 bus, such as on STM32MP25.
Finally this series also contains STM32MP25 device tree updates, to add
DMA support on SPI, I2C, UART and apply the tunings introduced.

Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>
---
Changes in v2:
- Reword commit title/message/content of patch 4 about preventing
  additionnal transfers, as per Rob's suggestion
- Rework AXI maximum burst length management using SoC specific
  compatible, as pointed out by Rob
- Drop former patches 6 and 8, which are no longer relevant
- Link to v1: https://lore.kernel.org/r/20241010-dma3-mp25-updates-v1-0-adf0633981ea@xxxxxxxxxxx

---
Amelie Delaunay (9):
      dt-bindings: dma: stm32-dma3: prevent packing/unpacking mode
      dmaengine: stm32-dma3: prevent pack/unpack thanks to DT configuration
      dmaengine: stm32-dma3: refactor HW linked-list to optimize memory accesses
      dt-bindings: dma: stm32-dma3: prevent additional transfers
      dmaengine: stm32-dma3: prevent LL refactoring thanks to DT configuration
      dmaengine: stm32-dma3: clamp AXI burst using match data
      arm64: dts: st: add DMA support on U(S)ART instances of stm32mp25
      arm64: dts: st: add DMA support on I2C instances of stm32mp25
      arm64: dts: st: add DMA support on SPI instances of stm32mp25

 .../bindings/dma/stm32/st,stm32-dma3.yaml          |   6 ++
 arch/arm64/boot/dts/st/stm32mp251.dtsi             |  75 +++++++++++++
 arch/arm64/boot/dts/st/stm32mp257f-ev1.dts         |   2 +
 drivers/dma/stm32/stm32-dma3.c                     | 119 +++++++++++++++++----
 4 files changed, 182 insertions(+), 20 deletions(-)
---
base-commit: 76355c25e4f71ee4667ebaadd9faf8ec29d18f23
change-id: 20241015-dma3-mp25-updates-d7f26753b0dd

Best regards,
-- 
Amelie Delaunay <amelie.delaunay@xxxxxxxxxxx>