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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)
downloadlwn-f5dcb68086ba2e033b2af32b0da0c7a7c7872a09.tar.gz
lwn-f5dcb68086ba2e033b2af32b0da0c7a7c7872a09.zip
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.