Re: [PATCH v2 0/7] ARM: Broadcom Brahma-B15 readahead cache support

[Florian Fainelli]

On 06/23/2017 10:52 AM, Florian Fainelli wrote:
> Hi all,
> 
> This patch series adds support for the Broadcom Brahma-B15 readahead cache.
> I submitted that patch series a couple of years ago, and then slept on it so
> here is another stab at it.
> 
> Note that we did not implement this cache as a version of an outer cache
> for several reasons:
> 
> - we initially thought we needed to intercept flush_icache_all and
>   flush_kern_cache_louis but upon further inspection we convinced ourselves
>   this is no longer needed, still, flush_cache_all() needs special handling
>   here and needs to be wrapped around
> 
> - the outer cache does not allow differentiating a DMA transfer direction
>   this is a readahead cache, so it does not participate in writes, flushing
>   it during reads *and* writes kills the performance completely
> 
> - finally, most operations that outer_cache cares about are on MVA, which
>   is transparent to the readahead cache here
> 
> Changes in v2:
> 
> - clarify that the read-ahead caches does invalidates on writes (IOW) based
>   on Russell's feedback

Any comments on this? Thank you.

> 
> Florian Fainelli (7):
>   ARM: v7: allow setting different cache functions
>   ARM: Add Broadcom Brahma-B15 readahead cache support
>   ARM: Hook B15 readahead cache functions based on processor
>   ARM: B15: Add CPU hotplug awareness
>   ARM: B15: Add suspend/resume hooks
>   ARM: B15: Register reboot notifier for KEXEC
>   MAINTAINERS: Update brcmstb entries to cover B15 code
> 
>  MAINTAINERS                                   |   2 +
>  arch/arm/include/asm/glue-cache.h             |   4 +
>  arch/arm/include/asm/hardware/cache-b15-rac.h |  10 +
>  arch/arm/mm/Kconfig                           |   8 +
>  arch/arm/mm/Makefile                          |   1 +
>  arch/arm/mm/cache-b15-rac.c                   | 360 ++++++++++++++++++++++++++
>  arch/arm/mm/cache-v7.S                        |  21 ++
>  arch/arm/mm/proc-v7.S                         |   6 +-
>  include/linux/cpuhotplug.h                    |   2 +
>  9 files changed, 411 insertions(+), 3 deletions(-)
>  create mode 100644 arch/arm/include/asm/hardware/cache-b15-rac.h
>  create mode 100644 arch/arm/mm/cache-b15-rac.c
> 


-- 
Florian