[PATCH v6 00/15] Add ACPI-based PMT discovery support for Intel PMC

["David E. Box" <david.e.box@linux.intel.com>]

This series adds ACPI-based PMT discovery support and wires it into the
Intel PMC telemetry stack for Nova Lake S.

Today, PMT discovery flow is primarily PCI-oriented. Some platforms expose
PMT discovery via ACPI _DSD, and PMC telemetry needs to consume that path
for both standalone and companion-device cases. This series addresses that
in three logical steps:

    1. Prepare intel_vsec for ACPI-backed discovery
    2. Refactor PMT class handling so discovery source is
       abstracted (PCI or ACPI)
    3. Add/enable PMC consumers using ACPI discovery, including NVL
       SSRAM support

Patches for step 1 were previously accepted. V4 onward includes the
remaining integration patches.

Testing:
Tested on Nova Lake S system and confirmed enumeration from both PCI and
ACPI enumerated PCD and PCH telemetry endpoints. Existing telemetry from
NVL CPU and an add-on Battlemage card also continued to work.

---
V6 changes:
- Squashed Xi Pardee's two patches (v5 patches 10 and 13) into a single
  patch (v6 patch 12). The two patches logically belonged together as
  they both addressed per-index probe state tracking and reentrant probe
  protection.
- Reordered v5 patch 12 ("Add PCI platform data") to v6 patch 10 to
  maintain better logical flow before the squashed probe state patch.
- Address other style and cleanup comments.

V5 changes:
- Addressed Ilpo Järvinen's review feedback on patches 08 and 14:
  - Added #include <linux/limits.h> for U16_MAX in pwrm_telemetry.c.
  - Split acpi_handle declaration from ACPI_HANDLE() assignment in both
    pmc_pwrm_acpi_probe() and pmc_ssram_telemetry_acpi_init(). The
    assignment now sits immediately above its !handle check.
  - Reordered local variables in those two functions in reverse-xmas-tree
    order.
- Patch 14: fixed a __free(pmc_acpi_free) ordering bug that caused
  buf.pointer to leak. The cleanup variable is now declared after
  acpi_evaluate_object() populates buf.pointer, and the GUID search
  operates on the cleanup variable so its current value tracks the
  actual allocation.
- Patches 05 and 06: bounded the new discovery-header memcpy_fromio()
  to resource_size() of the mapped DVSEC entry. The cache introduced in
  patch 05 (and the unified PCI header fetch in patch 06) would otherwise
  read 16 bytes from namespaces whose DVSEC entry_size is only 3 dwords
  (telemetry).
- Patch 06: documented in the ACPI branch that entry->disc_table = NULL
  is intentional, so consumers that dereference disc_table must only be
  wired to INTEL_VSEC_DISC_PCI namespaces.
- Remaining patches unchanged from v4.

V4 changes:
- Bound PMT discovery-header sizing to shared canonical definitions:
  - Added INTEL_VSEC_ACPI_DISC_DWORDS in intel_vsec API.
  - Added PMT_DISC_HEADER_DWORDS in PMT class, derived from the shared
    definition.
  - Replaced literal header copy sizes in PMT header fetch with size bound
    to entry->disc_header.
- Updated PMC ACPI discovery typing to use shared acpi_disc_t consistently:
  - acpi_disc_t now references INTEL_VSEC_ACPI_DISC_DWORDS.
  - pmc_parse_telem_dsd() uses acpi_disc_t return type and
    declaration-site allocation with __free(kfree).
  - Included intel_vsec header in PMC core declarations to align type
    ownership.
- In SSRAM ACPI scaffolding, switched temporary discovery pointer from raw
  u32 (*)[4] to acpi_disc_t for consistency with exported PMC helper types.
- Remaining patches unchanged from v3.

V3 changes:
- Dropped "platform/x86/intel/pmt: Move header decode into common helper"
- The dropped patch caused a crashlog regression because disc_res was
  accessed before assignment
- Updated the surrounding PMT patches to keep the needed ACPI header-fetch
  work without the dropped helper
- Added "platform/x86/intel/pmt: Cache the telemetry discovery header"
  to carry the post-v3 bug fix cleanly
- Dropped the standalone cleanup-pattern patch to keep the simpler
  ssram pointer flow requested in review

David E. Box (14):
  platform/x86/intel/pmt: Add pre/post decode hooks around header
    parsing
  platform/x86/intel/pmt/crashlog: Split init into pre-decode
  platform/x86/intel/pmt/telemetry: Move overlap check to post-decode
    hook
  platform/x86/intel/pmt: Pass discovery index instead of resource
  platform/x86/intel/pmt: Cache the telemetry discovery header
  platform/x86/intel/pmt: Unify header fetch and add ACPI source
  platform/x86/intel/pmc: Add PMC SSRAM Kconfig description
  platform/x86/intel/pmc: Add ACPI PWRM telemetry driver for Nova Lake S
  platform/x86/intel/pmc/ssram: Rename probe and PCI ID table for
    consistency
  platform/x86/intel/pmc/ssram: Add PCI platform data
  platform/x86/intel/pmc/ssram: Refactor DEVID/PWRMBASE extraction into
    helper
  platform/x86/intel/pmc/ssram: Add ACPI discovery scaffolding
  platform/x86/intel/pmc/ssram: Make PMT registration optional
  platform/x86/intel/pmc: Add NVL PCI IDs for SSRAM telemetry discovery

Xi Pardee (1):
  platform/x86/intel/pmc/ssram: Switch to static array with per-index
    probe state

 drivers/platform/x86/intel/pmc/Kconfig        |  25 ++
 drivers/platform/x86/intel/pmc/Makefile       |   2 +
 drivers/platform/x86/intel/pmc/core.h         |  16 +
 .../platform/x86/intel/pmc/pwrm_telemetry.c   | 216 ++++++++++
 .../platform/x86/intel/pmc/ssram_telemetry.c  | 376 +++++++++++++++---
 drivers/platform/x86/intel/pmt/class.c        | 156 +++++++-
 drivers/platform/x86/intel/pmt/class.h        |   6 +
 drivers/platform/x86/intel/pmt/crashlog.c     |  19 +-
 drivers/platform/x86/intel/pmt/telemetry.c    |  34 +-
 include/linux/intel_vsec.h                    |   5 +-
 10 files changed, 769 insertions(+), 86 deletions(-)
 create mode 100644 drivers/platform/x86/intel/pmc/pwrm_telemetry.c


base-commit: 069b06f8dfc9cdb34221c854653e7f54535e98e1
--
2.43.0