[PATCH V2 04/17] platform/x86/intel/pmt: Move header decode into common helper

David E. Box
2026-03-25T01:48:28Z

Unify PMT discovery table parsing by moving header decode logic into the
class driver. A new helper, pmt_read_header(), now fills in the standard
header fields from the discovery table, replacing the per-namespace
pmt_header_decode callbacks in telemetry and crashlog.

This centralizes the discovery table bit-field definitions in class.h,
removes duplicate decode code from telemetry and crashlog, and prepares the
PMT class for additional discovery sources.

Signed-off-by: David E. Box <david.e.box@linux.intel.com>
---

V2 changes:
- Added PMT_GET_SIZE_BYTES(v), addressing Ilpo feedback on macro naming
and unit clarity
- Also in PMT_GET_SIZE_BYTES(v) change ((v) << 2) to ((v) * sizeof(u32))
for clarity
- Removed unused macros from crashlog.c per feedback from Ilpo

drivers/platform/x86/intel/pmt/class.c | 37 +++++++++++++++-------
drivers/platform/x86/intel/pmt/class.h | 15 +++++++--
drivers/platform/x86/intel/pmt/crashlog.c | 23 --------------
drivers/platform/x86/intel/pmt/telemetry.c | 26 ---------------
4 files changed, 39 insertions(+), 62 deletions(-)

diff --git a/drivers/platform/x86/intel/pmt/class.c b/drivers/platform/x86/intel/pmt/class.c
index 9b315334a69b..d652b21261f0 100644
--- a/drivers/platform/x86/intel/pmt/class.c
+++ b/drivers/platform/x86/intel/pmt/class.c
@@ -8,6 +8,7 @@
* Author: "Alexander Duyck" <alexander.h.duyck@linux.intel.com>
*/

+#include <linux/bitfield.h>
#include <linux/kernel.h>
#include <linux/log2.h>
#include <linux/intel_vsec.h>
@@ -368,26 +369,40 @@ static int intel_pmt_dev_register(struct intel_pmt_entry *entry,
return ret;
}

-int intel_pmt_dev_create(struct intel_pmt_entry *entry, struct intel_pmt_namespace *ns,
- struct intel_vsec_device *intel_vsec_dev, int idx)
+static int pmt_read_header(struct intel_vsec_device *ivdev, int idx,
+ struct intel_pmt_entry *entry)
{
- struct device *dev = &intel_vsec_dev->auxdev.dev;
- struct resource *disc_res;
- int ret;
+ struct intel_pmt_header *header = &entry->header;
+ struct device *dev = &ivdev->auxdev.dev;
+ u64 headers[2];

- disc_res = &intel_vsec_dev->resource[idx];
-
- entry->disc_table = devm_ioremap_resource(dev, disc_res);
+ entry->disc_table = devm_ioremap_resource(dev, &ivdev->resource[idx]);
if (IS_ERR(entry->disc_table))
return PTR_ERR(entry->disc_table);

+ memcpy_fromio(headers, entry->disc_table, 2 * sizeof(u64));
+
+ header->access_type = FIELD_GET(PMT_ACCESS_TYPE, headers[0]);
+ header->telem_type = FIELD_GET(PMT_TELEM_TYPE, headers[0]);
+ header->size = PMT_GET_SIZE_BYTES(headers[0]);
+ header->guid = FIELD_GET(PMT_GUID32, headers[0]);
+ header->base_offset = FIELD_GET(PMT_BASE_OFFSET, headers[1]);
+
+ return 0;
+}
+
+int intel_pmt_dev_create(struct intel_pmt_entry *entry, struct intel_pmt_namespace *ns,
+ struct intel_vsec_device *intel_vsec_dev, int idx)
+{
+ int ret;
+
if (ns->pmt_pre_decode) {
ret = ns->pmt_pre_decode(intel_vsec_dev, entry);
if (ret)
return ret;
}

- ret = ns->pmt_header_decode(entry, dev);
+ ret = pmt_read_header(intel_vsec_dev, idx, entry);
if (ret)
return ret;

@@ -397,11 +412,11 @@ int intel_pmt_dev_create(struct intel_pmt_entry *entry, struct intel_pmt_namespa
return ret;
}

- ret = intel_pmt_populate_entry(entry, intel_vsec_dev, disc_res);
+ ret = intel_pmt_populate_entry(entry, intel_vsec_dev, &intel_vsec_dev->resource[idx]);
if (ret)
return ret;

- return intel_pmt_dev_register(entry, ns, dev);
+ return intel_pmt_dev_register(entry, ns, &intel_vsec_dev->auxdev.dev);
}
EXPORT_SYMBOL_NS_GPL(intel_pmt_dev_create, "INTEL_PMT");

diff --git a/drivers/platform/x86/intel/pmt/class.h b/drivers/platform/x86/intel/pmt/class.h
index 8a0db0ef58c1..96ebb15f0053 100644
--- a/drivers/platform/x86/intel/pmt/class.h
+++ b/drivers/platform/x86/intel/pmt/class.h
@@ -11,6 +11,19 @@

#include "telemetry.h"

+/* PMT Discovery Table DWORD 1 */
+#define PMT_ACCESS_TYPE GENMASK_ULL(3, 0)
+#define PMT_TELEM_TYPE GENMASK_ULL(7, 4)
+#define PMT_SIZE GENMASK_ULL(27, 12)
+#define PMT_GUID32 GENMASK_ULL(63, 32)
+
+/* PMT Discovery Table DWORD 2 */
+#define PMT_BASE_OFFSET GENMASK_ULL(31, 0)
+#define PMT_TELE_ID GENMASK_ULL(63, 32)
+
+/* Convert DWORD size to bytes */
+#define PMT_GET_SIZE_BYTES(h) ((FIELD_GET(PMT_SIZE, h)) * sizeof(u32))
+
/* PMT access types */
#define ACCESS_BARID 2
#define ACCESS_LOCAL 3
@@ -61,8 +74,6 @@ struct intel_pmt_entry {
struct intel_pmt_namespace {
const char *name;
struct xarray *xa;
- int (*pmt_header_decode)(struct intel_pmt_entry *entry,
- struct device *dev);
int (*pmt_pre_decode)(struct intel_vsec_device *ivdev,
struct intel_pmt_entry *entry);
int (*pmt_post_decode)(struct intel_vsec_device *ivdev,
diff --git a/drivers/platform/x86/intel/pmt/crashlog.c b/drivers/platform/x86/intel/pmt/crashlog.c
index f936daf99e4d..ef1826b15cf4 100644
--- a/drivers/platform/x86/intel/pmt/crashlog.c
+++ b/drivers/platform/x86/intel/pmt/crashlog.c
@@ -26,14 +26,8 @@

/* Crashlog Discovery Header */
#define CONTROL_OFFSET 0x0
-#define GUID_OFFSET 0x4
-#define BASE_OFFSET 0x8
-#define SIZE_OFFSET 0xC
-#define GET_ACCESS(v) ((v) & GENMASK(3, 0))
#define GET_TYPE(v) (((v) & GENMASK(7, 4)) >> 4)
#define GET_VERSION(v) (((v) & GENMASK(19, 16)) >> 16)
-/* size is in bytes */
-#define GET_SIZE(v) ((v) * sizeof(u32))

/*
* Type 1 Version 0
@@ -516,28 +510,11 @@ static int pmt_crashlog_pre_decode(struct intel_vsec_device *ivdev,
return 0;
}

-static int pmt_crashlog_header_decode(struct intel_pmt_entry *entry,
- struct device *dev)
-{
- void __iomem *disc_table = entry->disc_table;
- struct intel_pmt_header *header = &entry->header;
-
- header->access_type = GET_ACCESS(readl(disc_table));
- header->guid = readl(disc_table + GUID_OFFSET);
- header->base_offset = readl(disc_table + BASE_OFFSET);
-
- /* Size is measured in DWORDS, but accessor returns bytes */
- header->size = GET_SIZE(readl(disc_table + SIZE_OFFSET));
-
- return 0;
-}
-
static DEFINE_XARRAY_ALLOC(crashlog_array);
static struct intel_pmt_namespace pmt_crashlog_ns = {
.name = "crashlog",
.xa = &crashlog_array,
.pmt_pre_decode = pmt_crashlog_pre_decode,
- .pmt_header_decode = pmt_crashlog_header_decode,
};

/*
diff --git a/drivers/platform/x86/intel/pmt/telemetry.c b/drivers/platform/x86/intel/pmt/telemetry.c
index d22f633638be..80773e3c3efa 100644
--- a/drivers/platform/x86/intel/pmt/telemetry.c
+++ b/drivers/platform/x86/intel/pmt/telemetry.c
@@ -27,14 +27,6 @@

#include "class.h"

-#define TELEM_SIZE_OFFSET 0x0
-#define TELEM_GUID_OFFSET 0x4
-#define TELEM_BASE_OFFSET 0x8
-#define TELEM_ACCESS(v) ((v) & GENMASK(3, 0))
-#define TELEM_TYPE(v) (((v) & GENMASK(7, 4)) >> 4)
-/* size is in bytes */
-#define TELEM_SIZE(v) (((v) & GENMASK(27, 12)) >> 10)
-
/* Used by client hardware to identify a fixed telemetry entry*/
#define TELEM_CLIENT_FIXED_BLOCK_GUID 0x10000000

@@ -69,23 +61,6 @@ static bool pmt_telem_region_overlaps(struct device *dev, u32 guid, u32 type)
return false;
}

-static int pmt_telem_header_decode(struct intel_pmt_entry *entry,
- struct device *dev)
-{
- void __iomem *disc_table = entry->disc_table;
- struct intel_pmt_header *header = &entry->header;
-
- header->access_type = TELEM_ACCESS(readl(disc_table));
- header->guid = readl(disc_table + TELEM_GUID_OFFSET);
- header->base_offset = readl(disc_table + TELEM_BASE_OFFSET);
-
- /* Size is measured in DWORDS, but accessor returns bytes */
- header->size = TELEM_SIZE(readl(disc_table));
- header->telem_type = TELEM_TYPE(readl(entry->disc_table));
-
- return 0;
-}
-
static int pmt_telem_post_decode(struct intel_vsec_device *ivdev,
struct intel_pmt_entry *entry)
{
@@ -135,7 +110,6 @@ static DEFINE_XARRAY_ALLOC(telem_array);
static struct intel_pmt_namespace pmt_telem_ns = {
.name = "telem",
.xa = &telem_array,
- .pmt_header_decode = pmt_telem_header_decode,
.pmt_post_decode = pmt_telem_post_decode,
.pmt_add_endpoint = pmt_telem_add_endpoint,
};
--
2.43.0