On Mon, 2020-07-27 at 13:23 +0300, Andy Shevchenko wrote: > On Fri, Jul 17, 2020 at 10:05 PM David E. Box > <david.e.box@xxxxxxxxxxxxxxx> wrote: > > Intel Platform Monitoring Technology (PMT) is an architecture for > > enumerating and accessing hardware monitoring capabilities on a > > device. > > With customers increasingly asking for hardware telemetry, > > engineers not > > only have to figure out how to measure and collect data, but also > > how to > > deliver it and make it discoverable. The latter may be through some > > device > > specific method requiring device specific tools to collect the > > data. This > > in turn requires customers to manage a suite of different tools in > > order to > > collect the differing assortment of monitoring data on their > > systems. Even > > when such information can be provided in kernel drivers, they may > > require > > constant maintenance to update register mappings as they change > > with > > firmware updates and new versions of hardware. PMT provides a > > solution for > > discovering and reading telemetry from a device through a hardware > > agnostic > > framework that allows for updates to systems without requiring > > patches to > > the kernel or software tools. > > > > PMT defines several capabilities to support collecting monitoring > > data from > > hardware. All are discoverable as separate instances of the PCIE > > Designated > > Vendor extended capability (DVSEC) with the Intel vendor code. The > > DVSEC ID > > field uniquely identifies the capability. Each DVSEC also provides > > a BAR > > offset to a header that defines capability-specific attributes, > > including > > GUID, feature type, offset and length, as well as configuration > > settings > > where applicable. The GUID uniquely identifies the register space > > of any > > monitor data exposed by the capability. The GUID is associated with > > an XML > > file from the vendor that describes the mapping of the register > > space along > > with properties of the monitor data. This allows vendors to perform > > firmware updates that can change the mapping (e.g. add new metrics) > > without > > requiring any changes to drivers or software tools. The new mapping > > is > > confirmed by an updated GUID, read from the hardware, which > > software uses > > with a new XML. > > > > The current capabilities defined by PMT are Telemetry, Watcher, and > > Crashlog. The Telemetry capability provides access to a continuous > > block > > of read only data. The Watcher capability provides access to > > hardware > > sampling and tracing features. Crashlog provides access to device > > crash > > dumps. While there is some relationship between capabilities > > (Watcher can > > be configured to sample from the Telemetry data set) each exists as > > stand > > alone features with no dependency on any other. The design > > therefore splits > > them into individual, capability specific drivers. MFD is used to > > create > > platform devices for each capability so that they may be managed by > > their > > own driver. The PMT architecture is (for the most part) agnostic to > > the > > type of device it can collect from. Devices nodes are consequently > > generic > > in naming, e.g. /dev/telem<n> and /dev/smplr<n>. Each capability > > driver > > creates a class to manage the list of devices supporting > > it. Software can > > determine which devices support a PMT feature by searching through > > each > > device node entry in the sysfs class folder. It can additionally > > determine > > if a particular device supports a PMT feature by checking for a PMT > > class > > folder in the device folder. > > > > This patch set provides support for the PMT framework, along with > > support > > for Telemetry on Tiger Lake. > > > > I assume this goes thru MFD tree. Yes, looking for pull by MFD. Thanks Andy.
