Masayuki Ishikawa 69e6e17407 arch: imxrt: Enable IMXRT_ENET_ENHANCEDBD if !ARMV7M_DCACHE_WRITETHROUGH
Summary:
- I noticed that there are two kinds of descriptors for imxrt_enet.c
- The first one is the legacy descriptor and its size is 8bytes.
- The second one is the enhanced descriptor and its size is 32bytes.
- In both cases, we can not use a descriptor chain like stm32.
- Considering cache line alignment, the second one is perfect because
  one descriptor fits the Cortex-M7 cache line which would fix networking
  stability issues in d-cache write-back mode.

Impact:
- imxrt ethernet in d-cache write-back mode

Testing:
- Tested with ixmrt1060-evk:netnsh_dcache_wb (will be added later)

Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
2023-02-22 01:27:54 +08:00
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