Re: [PATCH 2/4] perf/arm-cmn: Add CMN-650 support

From: Will Deacon <will@kernel.org>
To: Ilkka Koskinen <ilkka@os.amperecomputing.com>
Cc: Robin Murphy <robin.murphy@arm.com>,
	mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/4] perf/arm-cmn: Add CMN-650 support
Date: Wed, 20 Apr 2022 10:26:45 +0100	[thread overview]
Message-ID: <20220420092644.GA6954@willie-the-truck> (raw)
In-Reply-To: <alpine.DEB.2.22.394.2204191637120.1991@ubuntu200401>

On Tue, Apr 19, 2022 at 04:47:11PM -0700, Ilkka Koskinen wrote:
> On Tue, 19 Apr 2022, Ilkka Koskinen wrote:
> > On Mon, 18 Apr 2022, Robin Murphy wrote:
> > > Add the identifiers and events for CMN-650, which slots into its
> > > evolutionary position between CMN-600 and the 700-series products.
> > > Imagine CMN-600 made bigger, and with most of the rough edges smoothed
> > > off, but that then balanced out by some bonkers PMU functionality for
> > > the new HN-P enhancement in CMN-650r2.
> > > 
> > > Most of the CXG events are actually common to newer revisions of CMN-600
> > > too, so they're arguably a little late; oh well.
> > > 
> > > Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> > > ---
> > > drivers/perf/arm-cmn.c | 222 ++++++++++++++++++++++++++++++++---------
> > > 1 file changed, 176 insertions(+), 46 deletions(-)
> > > 
> > > diff --git a/drivers/perf/arm-cmn.c b/drivers/perf/arm-cmn.c
> > > index 9c1d82be7a2f..cce8516d465c 100644
> > > --- a/drivers/perf/arm-cmn.c
> > > +++ b/drivers/perf/arm-cmn.c
> 
> 
> > > @@ -1979,6 +2108,7 @@ MODULE_DEVICE_TABLE(of, arm_cmn_of_match);
> > > #ifdef CONFIG_ACPI
> > > static const struct acpi_device_id arm_cmn_acpi_match[] = {
> > > 	{ "ARMHC600", CMN600 },
> > > +	{ "ARMHC650", CMN650 },
> > 
> > Not the great place for this comment but there probably isn't any better.
> > 
> > Based on DEN0093 v1.1, CMN's DSDT entries have been changed since
> > CMN-600. ROOTNODEBASE seems to be specific for CMN-600. Moreover, if you
> > compare the address maps in TRMs' Discovery chapters, you can see the
> > difference.
> > 
> > I'm thinking, at the minimal the second platform_get_resource() call has
> > to be skipped and zero returned in arm_cmn600_acpi_probe(), if the model
> > is cmn650 (probably also for cmn-700)
> 
> Uh, if only I had read the code more carefully, I had noticed that's what
> the driver does indeed.
> 
> 
> Anyway, so far it everything works fine. I test the driver a little more
> (and review the patches more carefully) and will let know how it goes.

Thanks for giving it a spin!

Please reply with a Tested-by if/when you're happy with them, then I can
queue them up (you've still got a couple of weeks, so no rush).

Cheers,

Will

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