[PATCH v3 0/4] Use dma_default_coherent for devicetree default coherency

[Jiaxun Yang]

Hi all,

This series split out second half of my previous series
"[PATCH 0/4] MIPS DMA coherence fixes".

It intends to use dma_default_coherent to determine the default coherency of
devicetree probed devices instead of hardcoding it with Kconfig options.

For some MIPS systems, dma_default_coherent is determined with either
bootloader or hardware registers in platform initilization code, and devicetree
does not explicility specify the coherency of the device, so we need the ability
to change the default coherency of devicetree probed devices.

For other platforms that supports noncoherent, dma_default_coherent is a fixed
value set by arch code. It's defaulted to false for most archs except RISC-V.

Thanks
- Jiaxun
---
v2:
  - Add PATCH 1 to help with backporting
  - Use Kconfig option to set dma_default_coherent 

v3:
  - Style fixes
  - Squash setting ARCH_DMA_DEFAULT_COHERENT into PATCH 4
  - Setting ARCH_DMA_DEFAULT_COHERENT for PowerPC

Jiaxun Yang (4):
  of: address: Fix default coherency for MIPS
  dma-mapping: Provide a fallback dma_default_coherent
  dma-mapping: Provide CONFIG_ARCH_DMA_DEFAULT_COHERENT
  of: address: Always use dma_default_coherent for default coherency

 arch/powerpc/Kconfig        | 2 +-
 arch/riscv/Kconfig          | 2 +-
 drivers/of/Kconfig          | 4 ----
 drivers/of/address.c        | 2 +-
 include/linux/dma-map-ops.h | 2 ++
 kernel/dma/Kconfig          | 7 +++++++
 kernel/dma/mapping.c        | 6 +++++-
 7 files changed, 17 insertions(+), 8 deletions(-)

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