MCTP and PLDM are the latest in Platform management Technology. Sw application and drivers can be implemented on the PCIe platform. Previously I spent some time on this. On Mon, Aug 10, 2020 at 7:49 PM David E. Box <david.e.box@xxxxxxxxxxxxxxx> wrote: > > Friendly ping. > > On Wed, 2020-07-29 at 14:37 -0700, David E. Box 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. > > > > Changes from V4: > > - Replace MFD with PMT in driver title > > - Fix commit tags in chronological order > > - Fix includes in alphabetical order > > - Use 'raw' string instead of defines for device names > > - Add an error message when returning an error code for > > unrecognized capability id > > - Use dev_err instead of dev_warn for messages when returning > > an error > > - Change while loop to call pci_find_next_ext_capability once > > - Add missing continue in while loop > > - Keep PCI platform defines using PCI_DEVICE_DATA magic tied to > > the pci_device_id table > > - Comment and kernel message cleanup > > > > Changes from V3: > > - Write out full acronym for DVSEC in PCI patch commit message > > and > > add 'Designated' to comments > > - remove unused variable caught by kernel test robot < > > lkp@xxxxxxxxx> > > - Add required Co-developed-by signoffs, noted by Andy > > - Allow access using new CAP_PERFMON capability as suggested by > > Alexey Bundankov > > - Fix spacing in Kconfig, noted by Randy > > - Other style changes and fixups suggested by Andy > > > > Changes from V2: > > - In order to handle certain HW bugs from the telemetry > > capability > > driver, create a single platform device per capability > > instead of > > a device per entry. Add the entry data as device resources > > and > > let the capability driver manage them as a set allowing for > > cleaner HW bug resolution. > > - Handle discovery table offset bug in intel_pmt.c > > - Handle overlapping regions in intel_pmt_telemetry.c > > - Add description of sysfs class to testing ABI. > > - Don't check size and count until confirming support for the > > PMT > > capability to avoid bailing out when we need to skip it. > > - Remove unneeded header file. Move code to the intel_pmt.c, > > the > > only place where it's needed. > > - Remove now unused platform data. > > - Add missing header files types.h, bits.h. > > - Rename file name and build options from telem to telemetry. > > - Code cleanup suggested by Andy S. > > - x86 mailing list added. > > > > Changes from V1: > > - In the telemetry driver, set the device in device_create() to > > the parent PCI device (the monitoring device) for clear > > association in sysfs. Was set before to the platform device > > created by the PCI parent. > > - Move telem struct into driver and delete unneeded header > > file. > > - Start telem device numbering from 0 instead of 1. 1 was used > > due to anticipated changes, no longer needed. > > - Use helper macros suggested by Andy S. > > - Rename class to pmt_telemetry, spelling out full name > > - Move monitor device name defines to common header > > - Coding style, spelling, and Makefile/MAINTAINERS ordering > > fixes > > > > David E. Box (3): > > PCI: Add defines for Designated Vendor-Specific Extended Capability > > mfd: Intel Platform Monitoring Technology support > > platform/x86: Intel PMT Telemetry capability driver > > > > .../ABI/testing/sysfs-class-pmt_telemetry | 46 ++ > > MAINTAINERS | 6 + > > drivers/mfd/Kconfig | 10 + > > drivers/mfd/Makefile | 1 + > > drivers/mfd/intel_pmt.c | 220 +++++++++ > > drivers/platform/x86/Kconfig | 10 + > > drivers/platform/x86/Makefile | 1 + > > drivers/platform/x86/intel_pmt_telemetry.c | 448 > > ++++++++++++++++++ > > include/uapi/linux/pci_regs.h | 5 + > > 9 files changed, 747 insertions(+) > > create mode 100644 Documentation/ABI/testing/sysfs-class- > > pmt_telemetry > > create mode 100644 drivers/mfd/intel_pmt.c > > create mode 100644 drivers/platform/x86/intel_pmt_telemetry.c > > >
