summary refs log tree commit diff
path: root/Documentation/arm
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-26 11:54:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-26 11:54:29 -0700
commitf5dcb68086ba2e033b2af32b0da0c7a7c7872a09 (patch)
tree89c41089b492f8d8d411185bd7cb07538802e837 /Documentation/arm
parent3d9f96d850e4bbfae24dc9aee03033dd77c81596 (diff)
parent4af34b572a85c44c55491a10693535a79627c478 (diff)
downloadlinux-f5dcb68086ba2e033b2af32b0da0c7a7c7872a09.tar.gz
Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver updates from Kevin Hilman:
 "Some of these are for drivers/soc, where we're now putting
  SoC-specific drivers these days.  Some are for other driver subsystems
  where we have received acks from the appropriate maintainers.

  Some highlights:

   - simple-mfd: document DT bindings and misc updates
   - migrate mach-berlin to simple-mfd for clock, pinctrl and reset
   - memory: support for Tegra132 SoC
   - memory: introduce tegra EMC driver for scaling memory frequency
   - misc. updates for ARM CCI and CCN busses"

* tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (48 commits)
  drivers: soc: sunxi: Introduce SoC driver to map SRAMs
  arm-cci: Add aliases for PMU events
  arm-cci: Add CCI-500 PMU support
  arm-cci: Sanitise CCI400 PMU driver specific code
  arm-cci: Abstract handling for CCI events
  arm-cci: Abstract out the PMU counter details
  arm-cci: Cleanup PMU driver code
  arm-cci: Do not enable CCI-400 PMU by default
  firmware: qcom: scm: Add HDCP Support
  ARM: berlin: add an ADC node for the BG2Q
  ARM: berlin: remove useless chip and system ctrl compatibles
  clk: berlin: drop direct of_iomap of nodes reg property
  ARM: berlin: move BG2Q clock node
  ARM: berlin: move BG2CD clock node
  ARM: berlin: move BG2 clock node
  clk: berlin: prepare simple-mfd conversion
  pinctrl: berlin: drop SoC stub provided regmap
  ARM: berlin: move pinctrl to simple-mfd nodes
  pinctrl: berlin: prepare to use regmap provided by syscon
  reset: berlin: drop arch_initcall initialization
  ...
Diffstat (limited to 'Documentation/arm')
-rw-r--r--Documentation/arm/CCN.txt17
1 files changed, 10 insertions, 7 deletions
diff --git a/Documentation/arm/CCN.txt b/Documentation/arm/CCN.txt
index 0632b3aad83e..ffca443a19b4 100644
--- a/Documentation/arm/CCN.txt
+++ b/Documentation/arm/CCN.txt
@@ -33,20 +33,23 @@ directory, with first 8 configurable by user and additional
 Cycle counter is described by a "type" value 0xff and does
 not require any other settings.
 
+The driver also provides a "cpumask" sysfs attribute, which contains
+a single CPU ID, of the processor which will be used to handle all
+the CCN PMU events. It is recommended that the user space tools
+request the events on this processor (if not, the perf_event->cpu value
+will be overwritten anyway). In case of this processor being offlined,
+the events are migrated to another one and the attribute is updated.
+
 Example of perf tool use:
 
 / # perf list | grep ccn
   ccn/cycles/                                        [Kernel PMU event]
 <...>
-  ccn/xp_valid_flit/                                 [Kernel PMU event]
+  ccn/xp_valid_flit,xp=?,port=?,vc=?,dir=?/          [Kernel PMU event]
 <...>
 
-/ # perf stat -C 0 -e ccn/cycles/,ccn/xp_valid_flit,xp=1,port=0,vc=1,dir=1/ \
+/ # perf stat -a -e ccn/cycles/,ccn/xp_valid_flit,xp=1,port=0,vc=1,dir=1/ \
                                                                        sleep 1
 
 The driver does not support sampling, therefore "perf record" will
-not work. Also notice that only single cpu is being selected
-("-C 0") - this is because perf framework does not support
-"non-CPU related" counters (yet?) so system-wide session ("-a")
-would try (and in most cases fail) to set up the same event
-per each CPU.
+not work. Per-task (without "-a") perf sessions are not supported.