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Box" cc: y@linux.intel.com, Rajneesh Bhardwaj , Hans de Goede , platform-driver-x86@vger.kernel.org, LKML , Xi Pardee , Srinivas Pandruvada Subject: Re: [PATCH v4 08/16] platform/x86/intel/pmc: Add ACPI PWRM telemetry driver for Nova Lake S In-Reply-To: <20260515002130.701457-9-david.e.box@linux.intel.com> Message-ID: <2f82b190-e5f1-6263-1c16-039f84c54193@linux.intel.com> References: <20260515002130.701457-1-david.e.box@linux.intel.com> <20260515002130.701457-9-david.e.box@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII On Thu, 14 May 2026, David E. Box wrote: > Add an ACPI-based PMC PWRM telemetry driver for Nova Lake S. The driver > locates PMT discovery data in _DSD under the Intel VSEC UUID, parses it, > and registers telemetry regions with the PMT/VSEC framework so PMC > telemetry is exposed via existing PMT interfaces. > > Export pmc_parse_telem_dsd() and pmc_find_telem_guid() to support ACPI > discovery in other PMC drivers (e.g., ssram_telemetry) without duplicating > ACPI parsing logic. Also export acpi_disc_t typedef from core.h for callers > to properly declare discovery table arrays. > > Selected by INTEL_PMC_CORE. Existing PCI functionality is preserved. > > Signed-off-by: David E. Box > --- > V4 changes: > - These changes were supposed to be in V3 > - Updated pmc_parse_telem_dsd() in pwrm_telemetry.c to use acpi_disc_t > in the function return type for consistency with the exported typedef > - In pmc_parse_telem_dsd(), change acpi_disc declaration to happen at the > allocation site as specified by cleanup.h > - Style, readability and cleanup-path refinement based on review > feedback > > V2 changes: > - Added explicit include for guid_t type availability in > core.h > - Added explicit include in pwrm_telemetry.c for GENMASK() > - Added and converted goto based cleanup to __free() > attributes per Ilpo's feedback > - Combined u64 hdr0 and u64 hdr1 into single declaration > - Converted pmc_parse_telem_dsd() to return acpi_disc directly with > ERR_PTR() for failures > - Added braces around _DSD evaluation failure path > > drivers/platform/x86/intel/pmc/Kconfig | 14 ++ > drivers/platform/x86/intel/pmc/Makefile | 2 + > drivers/platform/x86/intel/pmc/core.h | 16 ++ > .../platform/x86/intel/pmc/pwrm_telemetry.c | 214 ++++++++++++++++++ > 4 files changed, 246 insertions(+) > create mode 100644 drivers/platform/x86/intel/pmc/pwrm_telemetry.c > > diff --git a/drivers/platform/x86/intel/pmc/Kconfig b/drivers/platform/x86/intel/pmc/Kconfig > index 0f19dc7edcf9..937186b0b5dd 100644 > --- a/drivers/platform/x86/intel/pmc/Kconfig > +++ b/drivers/platform/x86/intel/pmc/Kconfig > @@ -9,6 +9,7 @@ config INTEL_PMC_CORE > depends on ACPI > depends on INTEL_PMT_TELEMETRY > select INTEL_PMC_SSRAM_TELEMETRY > + select INTEL_PMC_PWRM_TELEMETRY > help > The Intel Platform Controller Hub for Intel Core SoCs provides access > to Power Management Controller registers via various interfaces. This > @@ -39,3 +40,16 @@ config INTEL_PMC_SSRAM_TELEMETRY > (including sysfs). > > This option is selected by INTEL_PMC_CORE. > + > +config INTEL_PMC_PWRM_TELEMETRY > + tristate > + help > + This driver discovers PMC PWRM telemetry regions described in ACPI > + _DSD and registers them with the Intel VSEC framework as Intel PMT > + telemetry devices. > + > + It validates the ACPI discovery data and publishes the discovered > + regions so they can be accessed through the Intel PMT telemetry > + interfaces (including sysfs). > + > + This option is selected by INTEL_PMC_CORE. > diff --git a/drivers/platform/x86/intel/pmc/Makefile b/drivers/platform/x86/intel/pmc/Makefile > index bb960c8721d7..fdbb768f7b09 100644 > --- a/drivers/platform/x86/intel/pmc/Makefile > +++ b/drivers/platform/x86/intel/pmc/Makefile > @@ -12,3 +12,5 @@ obj-$(CONFIG_INTEL_PMC_CORE) += intel_pmc_core_pltdrv.o > # Intel PMC SSRAM driver > intel_pmc_ssram_telemetry-y += ssram_telemetry.o > obj-$(CONFIG_INTEL_PMC_SSRAM_TELEMETRY) += intel_pmc_ssram_telemetry.o > +intel_pmc_pwrm_telemetry-y += pwrm_telemetry.o > +obj-$(CONFIG_INTEL_PMC_PWRM_TELEMETRY) += intel_pmc_pwrm_telemetry.o > diff --git a/drivers/platform/x86/intel/pmc/core.h b/drivers/platform/x86/intel/pmc/core.h > index 118c8740ad3a..f458eb908c07 100644 > --- a/drivers/platform/x86/intel/pmc/core.h > +++ b/drivers/platform/x86/intel/pmc/core.h > @@ -14,10 +14,15 @@ > > #include > #include > +#include > +#include > #include > +#include > > struct telem_endpoint; > > +DEFINE_FREE(pmc_acpi_free, void *, if (_T) ACPI_FREE(_T)) > + > #define SLP_S0_RES_COUNTER_MASK GENMASK(31, 0) > > #define PMC_BASE_ADDR_DEFAULT 0xFE000000 > @@ -562,6 +567,8 @@ int pmc_core_pmt_get_blk_sub_req(struct pmc_dev *pmcdev, struct pmc *pmc, > extern const struct file_operations pmc_core_substate_req_regs_fops; > extern const struct file_operations pmc_core_substate_blk_req_fops; > > +extern const guid_t intel_vsec_guid; > + > #define pmc_for_each_mode(mode, pmc) \ > for (unsigned int __i = 0, __cond; \ > __cond = __i < (pmc)->num_lpm_modes, \ > @@ -583,4 +590,13 @@ static const struct file_operations __name ## _fops = { \ > .release = single_release, \ > } > > +struct intel_vsec_header; > +union acpi_object; > + > +/* Avoid checkpatch warning */ > +typedef u32 (*acpi_disc_t)[INTEL_VSEC_ACPI_DISC_DWORDS]; > + > +acpi_disc_t pmc_parse_telem_dsd(union acpi_object *obj, > + struct intel_vsec_header *header); > +union acpi_object *pmc_find_telem_guid(union acpi_object *dsd); > #endif /* PMC_CORE_H */ > diff --git a/drivers/platform/x86/intel/pmc/pwrm_telemetry.c b/drivers/platform/x86/intel/pmc/pwrm_telemetry.c > new file mode 100644 > index 000000000000..246256801f93 > --- /dev/null > +++ b/drivers/platform/x86/intel/pmc/pwrm_telemetry.c > @@ -0,0 +1,214 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * Intel PMC PWRM ACPI driver > + * > + * Copyright (C) 2025, Intel Corporation > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "core.h" > + > +#define ENTRY_LEN 5 > + > +/* DWORD2 */ > +#define DVSEC_ID_MASK GENMASK(15, 0) > +#define NUM_ENTRIES_MASK GENMASK(23, 16) > +#define ENTRY_SIZE_MASK GENMASK(31, 24) > + > +/* DWORD3 */ > +#define TBIR_MASK GENMASK(2, 0) > +#define DISC_TBL_OFF_MASK GENMASK(31, 3) > + > +const guid_t intel_vsec_guid = > + GUID_INIT(0x294903fb, 0x634d, 0x4fc7, 0xaf, 0x1f, 0x0f, 0xb9, > + 0x56, 0xb0, 0x4f, 0xc1); > + > +static bool is_valid_entry(union acpi_object *pkg) > +{ > + int i; > + > + if (!pkg || pkg->type != ACPI_TYPE_PACKAGE || pkg->package.count != ENTRY_LEN) > + return false; > + > + if (pkg->package.elements[0].type != ACPI_TYPE_STRING) > + return false; > + > + for (i = 1; i < ENTRY_LEN; i++) > + if (pkg->package.elements[i].type != ACPI_TYPE_INTEGER) > + return false; > + > + return true; > +} > + > +acpi_disc_t pmc_parse_telem_dsd(union acpi_object *obj, > + struct intel_vsec_header *header) > +{ > + union acpi_object *vsec_pkg; > + union acpi_object *disc_pkg; > + u64 hdr0, hdr1; > + int num_regions; > + int i; > + > + if (!header) > + return ERR_PTR(-EINVAL); > + > + if (!obj || obj->type != ACPI_TYPE_PACKAGE || obj->package.count != 2) > + return ERR_PTR(-EINVAL); > + > + /* First Package is DVSEC info */ > + vsec_pkg = &obj->package.elements[0]; > + if (!is_valid_entry(vsec_pkg)) > + return ERR_PTR(-EINVAL); > + > + hdr0 = vsec_pkg->package.elements[3].integer.value; > + hdr1 = vsec_pkg->package.elements[4].integer.value; > + > + header->id = FIELD_GET(DVSEC_ID_MASK, hdr0); > + header->num_entries = FIELD_GET(NUM_ENTRIES_MASK, hdr0); > + header->entry_size = FIELD_GET(ENTRY_SIZE_MASK, hdr0); > + header->tbir = FIELD_GET(TBIR_MASK, hdr1); > + header->offset = FIELD_GET(DISC_TBL_OFF_MASK, hdr1); > + > + /* Second Package contains the discovery tables */ > + disc_pkg = &obj->package.elements[1]; > + if (disc_pkg->type != ACPI_TYPE_PACKAGE || disc_pkg->package.count < 1) > + return ERR_PTR(-EINVAL); > + > + num_regions = disc_pkg->package.count; > + if (header->num_entries != num_regions) > + return ERR_PTR(-EINVAL); > + > + acpi_disc_t disc __free(kfree) = kmalloc_array(num_regions, sizeof(*disc), > + GFP_KERNEL); > + if (!disc) > + return ERR_PTR(-ENOMEM); > + > + for (i = 0; i < num_regions; i++) { > + union acpi_object *pkg; > + u64 value; > + int j; > + > + pkg = &disc_pkg->package.elements[i]; > + if (!is_valid_entry(pkg)) > + return ERR_PTR(-EINVAL); > + > + /* Element 0 is a descriptive string; DWORD values start at index 1. */ > + for (j = 1; j < ENTRY_LEN; j++) { > + value = pkg->package.elements[j].integer.value; > + if (value > U32_MAX) Please add limits.h. > + return ERR_PTR(-ERANGE); > + > + disc[i][j - 1] = value; > + } > + } > + > + return no_free_ptr(disc); > +} > +EXPORT_SYMBOL_NS_GPL(pmc_parse_telem_dsd, "INTEL_PMC_CORE"); > + > +union acpi_object *pmc_find_telem_guid(union acpi_object *dsd) > +{ > + int i; > + > + if (!dsd || dsd->type != ACPI_TYPE_PACKAGE) > + return NULL; > + > + for (i = 0; i + 1 < dsd->package.count; i += 2) { > + union acpi_object *uuid_obj, *data_obj; > + guid_t uuid; > + > + uuid_obj = &dsd->package.elements[i]; > + data_obj = &dsd->package.elements[i + 1]; > + > + if (uuid_obj->type != ACPI_TYPE_BUFFER || > + uuid_obj->buffer.length != 16) > + continue; > + > + memcpy(&uuid, uuid_obj->buffer.pointer, 16); > + if (guid_equal(&uuid, &intel_vsec_guid)) > + return data_obj; > + } > + > + return NULL; > +} > +EXPORT_SYMBOL_NS_GPL(pmc_find_telem_guid, "INTEL_PMC_CORE"); > + > +static int pmc_pwrm_acpi_probe(struct platform_device *pdev) > +{ > + struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER, NULL }; > + acpi_handle handle = ACPI_HANDLE(&pdev->dev); Move the assignment next to !handle check. > + struct intel_vsec_header header; > + struct intel_vsec_header *headers[2] = { &header, NULL }; > + struct intel_vsec_platform_info info = { }; > + struct device *dev = &pdev->dev; > + struct resource *res; > + union acpi_object *dsd; > + acpi_status status; Please try to rearrange these to the reverse xmas-tree order to the extent possible (the same comment is relevant for patch 14 too once you make the handle line shorter). > + > + if (!handle) > + return -ENODEV; > + > + status = acpi_evaluate_object(handle, "_DSD", NULL, &buf); > + if (ACPI_FAILURE(status)) { > + return dev_err_probe(dev, -ENODEV, "Could not evaluate _DSD: %s\n", > + acpi_format_exception(status)); > + } > + > + void *dsd_buf __free(pmc_acpi_free) = buf.pointer; > + > + dsd = pmc_find_telem_guid(dsd_buf); > + if (!dsd) > + return -ENODEV; > + > + acpi_disc_t acpi_disc __free(kfree) = pmc_parse_telem_dsd(dsd, &header); > + if (IS_ERR(acpi_disc)) > + return PTR_ERR(acpi_disc); > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, header.tbir); > + if (!res) > + return -EINVAL; > + > + info.headers = headers; > + info.caps = VSEC_CAP_TELEMETRY; > + info.acpi_disc = acpi_disc; > + info.src = INTEL_VSEC_DISC_ACPI; > + info.base_addr = res->start; > + > + return intel_vsec_register(&pdev->dev, &info); > +} > + > +static const struct acpi_device_id pmc_pwrm_acpi_ids[] = { > + { "INTC1122", 0 }, /* Nova Lake */ > + { "INTC1129", 0 }, /* Nova Lake */ > + { } > +}; > +MODULE_DEVICE_TABLE(acpi, pmc_pwrm_acpi_ids); > + > +static struct platform_driver pmc_pwrm_acpi_driver = { > + .probe = pmc_pwrm_acpi_probe, > + .driver = { > + .name = "intel_pmc_pwrm_acpi", > + .acpi_match_table = ACPI_PTR(pmc_pwrm_acpi_ids), > + }, > +}; > +module_platform_driver(pmc_pwrm_acpi_driver); > + > +MODULE_AUTHOR("David E. Box "); > +MODULE_DESCRIPTION("Intel PMC PWRM ACPI driver"); > +MODULE_LICENSE("GPL"); > +MODULE_IMPORT_NS("INTEL_VSEC"); > -- i.