linux-kernel - [PATCH] platform/x86/intel-uncore-freq: Present unique domain ID per package

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Message-ID: <20250727211051.2898789-1-srinivas.pandruvada@linux.intel.com>
Date: Sun, 27 Jul 2025 14:10:51 -0700
From: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
To: hdegoede@...hat.com,
	ilpo.jarvinen@...ux.intel.com
Cc: platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Subject: [PATCH] platform/x86/intel-uncore-freq: Present unique domain ID per package

In partitioned systems, the domain ID is unique in the partition and a
package can have multiple partitions.

Some user-space tools, such as turbostat, assume the domain ID is unique
per package. These tools map CPU power domains, which are unique to a
package. However, this approach does not work in partitioned systems.

There is no architectural definition of "partition" to present to user
space.

To support these tools, set the domain_id to be unique per package. For
compute die IDs, uniqueness can be achieved using the platform info
cdie_mask, mirroring the behavior observed in non-partitioned systems.

For IO dies, which lack a direct CPU relationship, any unique logical
ID can be assigned. Here domain IDs for IO dies are configured after all
compute domain IDs. During the probe, keep the index of the next IO
domain ID after the last IO domain ID of the current partition. Since
CPU packages are symmetric, partition information is same for all
packages.

The Intel Speed Select driver has already implemented a similar change
to make the domain ID unique, with compute dies listed first, followed
by I/O dies.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
---
Rebased on
https://kernel.googlesource.com/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86
for-next

 .../uncore-frequency/uncore-frequency-tpmi.c  | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
index bfcf92aa4d69..563e215b4076 100644
--- a/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
+++ b/drivers/platform/x86/intel/uncore-frequency/uncore-frequency-tpmi.c
@@ -411,6 +411,47 @@ static int uncore_read(struct uncore_data *data, unsigned int *value, enum uncor
 	return -EOPNOTSUPP;
 }
 
+#define MAX_PARTITIONS	2
+
+/* IO domain ID start index for a partition */
+static u8 io_die_start[MAX_PARTITIONS];
+
+/* Next IO domain ID index after the current partition IO die IDs */
+static u8 io_die_index_next;
+
+/* Lock to protect io_die_start, io_die_index_next */
+static DEFINE_MUTEX(domain_lock);
+
+static void update_domain_id(struct tpmi_uncore_cluster_info *cluster_info,
+			     struct oobmsm_plat_info *plat_info, int num_resource)
+{
+	u8 max_dies = topology_max_dies_per_package();
+	u8 cdie_cnt;
+
+	/* For non partitioned system or invalid partition number, return */
+	if (!plat_info->cdie_mask || max_dies <= 1 || plat_info->partition >= MAX_PARTITIONS)
+		return;
+
+	if (cluster_info->uncore_data.agent_type_mask & AGENT_TYPE_CORE) {
+		cluster_info->uncore_data.domain_id = cluster_info->cdie_id;
+		return;
+	}
+
+	cdie_cnt = fls(plat_info->cdie_mask) - ffs(plat_info->cdie_mask) + 1;
+
+	guard(mutex)(&domain_lock);
+
+	if (!io_die_index_next)
+		io_die_index_next = max_dies;
+
+	if (!io_die_start[plat_info->partition]) {
+		io_die_start[plat_info->partition] = io_die_index_next;
+		io_die_index_next += (num_resource - cdie_cnt);
+	}
+
+	cluster_info->uncore_data.domain_id += (io_die_start[plat_info->partition] - cdie_cnt);
+}
+
 /* Callback for sysfs write for TPMI uncore data. Called under mutex locks. */
 static int uncore_write(struct uncore_data *data, unsigned int value, enum uncore_index index)
 {
@@ -614,6 +655,7 @@ static int uncore_probe(struct auxiliary_device *auxdev, const struct auxiliary_
 			cluster_info->uncore_data.cluster_id = j;
 
 			set_cdie_id(i, cluster_info, plat_info);
+			update_domain_id(cluster_info, plat_info, num_resources);
 
 			cluster_info->uncore_root = tpmi_uncore;
 
-- 
2.49.0