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AmbaProt memory type for non-cacheable fetches should be "Normal Non-cacheable Bufferable" #2928

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merged 2 commits into from
Jan 18, 2022

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ingallsj
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Related issue: follow-up to #2386

Type of change: bug report

Impact: functional change

Development Phase: implementation

Release Notes
We don't believe anything inside Rocket-chip was depending on this.
If somebody was using the Cacheable bit from a Non-cacheable AXI or AHB port, then this would be an errata.
The AMBA AXI protocol specification includes a section “Mismatched memory attributes” which says:

Multiple agents that are accessing the same area of memory, can use mismatched memory attributes. However, for functional correctness, the following rules must be obeyed:

  • All masters accessing the same area of memory must have a consistent view of the Cacheability …

@ingallsj ingallsj merged commit 7bd6b1a into master Jan 18, 2022
@ingallsj ingallsj deleted the icache-amba-alloc branch January 18, 2022 18:51
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