Thread (4 messages) 4 messages, 3 authors, 2016-09-02

[PATCHv4] arm: l2x0: add PMU support

From: linux@armlinux.org.uk (Russell King - ARM Linux)
Date: 2016-09-01 15:37:07

On Wed, Aug 31, 2016 at 03:23:36PM +0100, Mark Rutland wrote:
The L2C-220 (AKA L220) and L2C-310 (AKA PL310) cache controllers feature
a Performance Monitoring Unit (PMU), which can be useful for tuning
and/or debugging. This hardware is always present and the relevant
registers are accessible to non-secure accesses. Thus, no special
firmware interface is necessary.

This patch adds support for the PMU, plugging into the usual perf
infrastructure. The overflow interrupt is not always available (e.g. on
RealView PBX A9 it is not wired up at all), and the hardware counters
saturate, so the driver does not make use of this. Instead, the driver
periodically polls and reset counters as required to avoid losing
events due to saturation.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Pawel Moll <redacted>
Cc: Kim Phillips <redacted>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <redacted>
Much better, thanks.  When you're happy, please put it in the patch
system, thanks.

-- 
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help