On Wed, Dec 19, 2012 at 11:23:14AM +0000, Will Deacon wrote: > Hi Pratik, > > On Tue, Dec 18, 2012 at 07:19:17PM +0000, prat...@codeaurora.org wrote: > > This RFC is aimed at introducing CoreSight framework as well as > > individual CoreSight trace component drivers adhering to ARM > > CoreSight specification. Some prior discussion on this can be > > referred at [1]. > > > > There are 3 kinds of CoreSight trace components: > > > > * Sources: Responsible for producing trace data to provide > > visibility for the associated entity. > > > > * Links: Transport components that carry trace data. > > > > * Sinks: Collectors for storing trace data or acting as conduits > > for off-chip trace data collection. > > > > These components can be connected in various topologies to suite > > a particular SoCs tracing needs. > > > > Framework is responsible for gathering and using the information > > about the registered CoreSight components and their connections > > to allow it to dynamically deduce the sequence of components > > representing a connection from a CoreSight source to the > > currently selected CoreSight sink. This helps the framework to > > program the correct set of components to satisfy user request. > > From a million miles up, this looks like a sensible sort of design but I > really think you need to talk to Jon Hunter (he's at least on CC) about > this, especially where bindings are concerned. If we can get something that > you both agree on, then we can include the CTI with the other coresight > components and do a more in-depth review at that point. >
Thanks for the feedback. > Finally, how do you plan on exposing this data to the user? I think the only > sane way is to have per-device file descriptors which act as pipes to the raw > data but this means we need some readily available, open-source tooling (or > at least public specifications of the trace formats). > The sink drivers (ETB, TMC), expose a device node per device that is used to collect the raw data. Eg:, we have: /dev/coresight-etb /dev/coresight-tmc-etf /dev/coresight-tmc-etr where reading /dev/coresight-tmc-etf only works when the ETF is in circular buffer mode. -- Employee of Qualcomm Innovation Center, Inc. Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
