summaryrefslogtreecommitdiffstats
path: root/Documentation/ioctl
diff options
context:
space:
mode:
authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2015-09-22 15:47:10 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-10-04 20:28:58 +0100
commit7bd1d4093c2fa37d1ecab05da3c9d48ea2af2264 (patch)
tree24400395a4d56de0499f61e423529769f46fd83f /Documentation/ioctl
parent9b76968db6869666c9b30ea99894e9dd88a0ab13 (diff)
downloadop-kernel-dev-7bd1d4093c2fa37d1ecab05da3c9d48ea2af2264.zip
op-kernel-dev-7bd1d4093c2fa37d1ecab05da3c9d48ea2af2264.tar.gz
stm class: Introduce an abstraction for System Trace Module devices
A System Trace Module (STM) is a device exporting data in System Trace Protocol (STP) format as defined by MIPI STP standards. Examples of such devices are Intel(R) Trace Hub and Coresight STM. This abstraction provides a unified interface for software trace sources to send their data over an STM device to a debug host. In order to do that, such a trace source needs to be assigned a pair of master/channel identifiers that all the data from this source will be tagged with. The STP decoder on the debug host side will use these master/channel tags to distinguish different trace streams from one another inside one STP stream. This abstraction provides a configfs-based policy management mechanism for dynamic allocation of these master/channel pairs based on trace source-supplied string identifier. It has the flexibility of being defined at runtime and at the same time (provided that the policy definition is aligned with the decoding end) consistency. For userspace trace sources, this abstraction provides write()-based and mmap()-based (if the underlying stm device allows this) output mechanism. For kernel-side trace sources, we provide "stm_source" device class that can be connected to an stm device at run time. Cc: linux-api@vger.kernel.org Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'Documentation/ioctl')
-rw-r--r--Documentation/ioctl/ioctl-number.txt3
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/ioctl/ioctl-number.txt b/Documentation/ioctl/ioctl-number.txt
index df1b25e..3785b7e 100644
--- a/Documentation/ioctl/ioctl-number.txt
+++ b/Documentation/ioctl/ioctl-number.txt
@@ -81,6 +81,9 @@ Code Seq#(hex) Include File Comments
0x22 all scsi/sg.h
'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
'$' 00-0F linux/perf_counter.h, linux/perf_event.h
+'%' 00-0F include/uapi/linux/stm.h
+ System Trace Module subsystem
+ <mailto:alexander.shishkin@linux.intel.com>
'&' 00-07 drivers/firewire/nosy-user.h
'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
OpenPOWER on IntegriCloud