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    SubjectRe: [PATCH v2 0/3] Intel Platform Monitoring Technology
    On Fri, May 8, 2020 at 5:18 AM David E. Box <david.e.box@linux.intel.com> 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.
    >

    Some nitpicks per individual patches, also you forgot to send the
    series to PDx86 mailing list and its maintainers (only me included).

    > 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
    >
    > MAINTAINERS | 6 +
    > drivers/mfd/Kconfig | 10 +
    > drivers/mfd/Makefile | 1 +
    > drivers/mfd/intel_pmt.c | 170 ++++++++++++
    > drivers/platform/x86/Kconfig | 10 +
    > drivers/platform/x86/Makefile | 1 +
    > drivers/platform/x86/intel_pmt_telem.c | 362 +++++++++++++++++++++++++
    > include/linux/intel-dvsec.h | 48 ++++
    > include/uapi/linux/pci_regs.h | 5 +
    > 9 files changed, 613 insertions(+)
    > create mode 100644 drivers/mfd/intel_pmt.c
    > create mode 100644 drivers/platform/x86/intel_pmt_telem.c
    > create mode 100644 include/linux/intel-dvsec.h
    >
    > --
    > 2.20.1
    >


    --
    With Best Regards,
    Andy Shevchenko

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