DMA设计调研

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参考资料：
Direct memory access

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DMA除了用于CPU内存和外设的数据传输， 还可以更细粒度，例如 PE和核内缓存间的数据传输

DMA is also used for intra-chip data transfer in multi-core processors. Computers that have DMA channels can transfer data to and from devices with much less CPU overhead than computers without DMA channels. Similarly, a processing element inside a multi-core processor can transfer data to and from its local memory without occupying its processor time, allowing computation and data transfer to proceed in parallel.

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DMA导致CACHE一致性问题

解决方法：

Cache-coherent systems implement a method in hardware whereby external writes are signaled to the cache controller which then performs a cache invalidation for DMA writes or cache flush for DMA reads.

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DMA用于PE间的数据传输 例子

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DMA 取数模式 stride memory access

https://www.embedded.com/using-direct-memory-access-effectively-in-media-based-embedded-applications-part-1/

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chisel实现DMA模块

• https://github.com/antmicro/fastvdma
  

• icenet
  是一个网卡模型，里面取数用了DMA模块，可以参考