Re: [PATCH v5 0/3] arm64: qcom: sa8775p: add cache coherency support for SA8775P

[Krzysztof Kozlowski]

On 23/02/2024 15:03, Mrinmay Sarkar wrote:
> Due to some hardware changes, SA8775P has set the NO_SNOOP attribute
> in its TLP for all the PCIe controllers. NO_SNOOP attribute when set,
> the requester is indicating that there no cache coherency issues exit
> for the addressed memory on the host i.e., memory is not cached. But
> in reality, requester cannot assume this unless there is a complete
> control/visibility over the addressed memory on the host.
> 
> And worst case, if the memory is cached on the host, it may lead to
> memory corruption issues. It should be noted that the caching of memory
> on the host is not solely dependent on the NO_SNOOP attribute in TLP.
> 
> So to avoid the corruption, this patch overrides the NO_SNOOP attribute
> by setting the PCIE_PARF_NO_SNOOP_OVERIDE register. This patch is not
> needed for other upstream supported platforms since they do not set
> NO_SNOOP attribute by default.
> 
> This series is to enable cache snooping logic in both RC and EP driver
> and add the "dma-coherent" property in dtsi to support cache coherency
> in SA8775P platform.

Please confirm that your patchset passes 100% dtbs_check.

Best regards,
Krzysztof