[PATCH v2 0/9] dmaengine: Support bus widths of 32 bytes and above

The DMA engine slave capabilities advertise the supported source and
destination bus widths through src_addr_widths / dst_addr_widths. These
are plain u32 bitmasks where a set bit's position equals the
corresponding enum dma_slave_buswidth value, e.g.
DMA_SLAVE_BUSWIDTH_4_BYTES sets bit 4.

The consequence is that widths of 32 bytes and above cannot be
represented at all: DMA_SLAVE_BUSWIDTH_32/64/128_BYTES would need bits
32, 64 and 128, which do not fit in a u32. Hardware with wider data
paths is becoming common, so add a representation that can express these
widths while still using enum dma_slave_buswidth.

This series switches consumers and a small set of producers to bitmap
based bus width capabilities. The legacy dma_device u32 fields are kept
for now so the remaining DMA controller drivers can be converted
incrementally. dma_get_slave_caps() folds legacy producer masks into the
new bitmap representation returned to consumers.

Once the remaining producers are converted, the legacy dma_device
src/dst_addr_widths fields can be removed as a final cleanup.

This issue was discussed before here:

https://lore.kernel.org/dmaengine/abkoXXbaxaiqbBuX@vaman/

---
Changes in v2:
- Patch 5:
  - Goto the error label instead of directly returning so the clock is
    disabled if setting the bus width capabilities fails.
- Patch 9:
  - Improve the commit message to make it explicit that only the
    struct dma_slave_caps legacy fields are removed and that the
    struct dma_device ones are kept until all the DMA controller drivers
    are converted.
- Link to v1: https://patch.msgid.link/20260730-dmaengine-support-wider-dma-masks-v1-0-3732f1f9d9ca@analog.com

---
Nuno Sá (9):
      dmaengine: Support bus widths of 32 bytes and above
      dmaengine: dma-axi-dmac: Use bus width capability helpers
      dmaengine: dw-axi-dmac: Use bus width capability helpers
      dmaengine: qcom: gpi: Use bus width capability helpers
      dmaengine: stm32-dma3: Use bus width capability helpers
      iio: buffer-dmaengine: Use dma_slave_caps bus width accessors
      ALSA: pcm_dmaengine: Use dma_slave_caps bus width helpers
      spi: dw: Use dma_slave_caps bus width helpers
      dmaengine: Drop legacy bus width fields from dma_slave_caps

 drivers/dma/dma-axi-dmac.c                         |  13 +-
 drivers/dma/dmaengine.c                            |  20 +-
 drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c     |  39 ++--
 drivers/dma/qcom/gpi.c                             |  11 +-
 drivers/dma/stm32/stm32-dma3.c                     |  32 +--
 drivers/iio/buffer/industrialio-buffer-dmaengine.c |  15 +-
 drivers/spi/spi-dw-dma.c                           |   6 +-
 drivers/spi/spi-dw.h                               |   3 +-
 include/linux/dmaengine.h                          | 234 ++++++++++++++++++++-
 sound/core/pcm_dmaengine.c                         |  14 +-
 10 files changed, 323 insertions(+), 64 deletions(-)
---
base-commit: 0613e7934ee233d726af8d8c89f251a1c4df738d
change-id: 20260615-dmaengine-support-wider-dma-masks-5aac12497e27
--

Thanks!
- Nuno Sá