Re: [PATCH v3] perf: Add Arm Bus Monitor Unit driver

[Will Deacon <will@kernel.org>]

On Thu, Sep 17, 2026 at 02:47:12PM +0100, Robin Murphy wrote:
> Arm's Bus Monitor Unit is a low-level performance analysis tool for
> matching and counting transactions at interconnect interfaces. Each
> BMU consists of a number of "interface monitoring units", with some
> global controls to synchronise them and so permit accurate calculation
> of cross-interface metrics. Each IMU contains, among other things, its
> own PMU largely based on the CoreSight PMU architecture, but with some
> functional incompatibilities due to the nature of how much per-event
> filtering needs to be crammed in to categorise AXI/CHI transactions at
> the protocol level. As such it gets an honorary home in arm_cspmu/ in
> order to share the common register definitions, but for simplicity does
> not try to bend the functional abstraction to fit.
> 
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> 
> ---
> v3:
>  - Couple of inconsequential tweaks to shut Sashiko up about things
>    that would never actually happen anyway
>  - Drop unneeded DT patches that I can't be bothered to fix right now

Please can you take a look at the Sashiko comments on this one?

Will