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    Subject[PATCH V3 0/3] Intel Platform Monitoring Technology
    Date
    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 V2:

    Please excuse this delayed V3 as we dealt with last minute hardware
    changes.

    - 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 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 | 218 +++++++++
    drivers/platform/x86/Kconfig | 10 +
    drivers/platform/x86/Makefile | 1 +
    drivers/platform/x86/intel_pmt_telemetry.c | 454 ++++++++++++++++++
    include/uapi/linux/pci_regs.h | 5 +
    9 files changed, 751 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

    --
    2.20.1

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