[PATCH 2/2] drm/xe/cri: Expose device UUID through sysfs

[Badal Nilawar <badal.nilawar@intel.com>]

Expose a read-only sysfs attribute, device_uuid, that reports the
GPU's unique hardware identifier.

Assisted-by: Claude:claude-opus-4.8
Signed-off-by: Badal Nilawar <badal.nilawar@intel.com>
---
 .../ABI/testing/sysfs-driver-intel-xe-gpu     | 10 ++++++
 drivers/gpu/drm/xe/regs/xe_regs.h             |  2 ++
 drivers/gpu/drm/xe/xe_device.c                |  3 ++
 drivers/gpu/drm/xe/xe_device_sysfs.c          | 36 +++++++++++++++++++
 drivers/gpu/drm/xe/xe_device_types.h          |  3 ++
 5 files changed, 54 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-driver-intel-xe-gpu

diff --git a/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu b/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
new file mode 100644
index 000000000000..1a4bdfbad8d7
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-driver-intel-xe-gpu
@@ -0,0 +1,10 @@
+What:		/sys/bus/pci/drivers/xe/.../device_uuid
+Date:		September 2026
+KernelVersion:	7.4
+Contact:	intel-xe@lists.freedesktop.org
+Description:	RO. Unique 64-bit identifier of the device instance, read from
+		the device's CRI_DEVICE_UUID register and printed as a
+		zero-padded 16-digit hexadecimal string.
+
+		This sysfs file is present only on Intel Xe platforms that
+		provide a device UUID. It is available to all users.
diff --git a/drivers/gpu/drm/xe/regs/xe_regs.h b/drivers/gpu/drm/xe/regs/xe_regs.h
index ef4746b7b5d3..68226fe0b659 100644
--- a/drivers/gpu/drm/xe/regs/xe_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_regs.h
@@ -30,6 +30,8 @@
 #define XEHP_MTCFG_ADDR				XE_REG(0x101800)
 #define   TILE_COUNT				REG_GENMASK(15, 8)
 
+#define CRI_DEVICE_UUID				XE_REG(0x102008)
+
 #define GGC					XE_REG(0x108040)
 #define   GMS_MASK				REG_GENMASK(15, 8)
 #define   GGMS_MASK				REG_GENMASK(7, 6)
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 8583b2e9ecf4..e8db8871990b 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -801,6 +801,9 @@ int xe_device_probe_early(struct xe_device *xe)
 	if (IS_SRIOV_VF(xe))
 		vf_update_device_info(xe);
 
+	if (xe->info.platform == XE_CRESCENTISLAND)
+		xe->device_uuid = xe_mmio_read64_2x32(xe_root_tile_mmio(xe), CRI_DEVICE_UUID);
+
 	/*
 	 * Check for pcode uncore_init status to confirm if the SoC
 	 * initialization is complete. Until done, any MMIO or lmem access from
diff --git a/drivers/gpu/drm/xe/xe_device_sysfs.c b/drivers/gpu/drm/xe/xe_device_sysfs.c
index a73e0e957cb0..a4d326159dce 100644
--- a/drivers/gpu/drm/xe/xe_device_sysfs.c
+++ b/drivers/gpu/drm/xe/xe_device_sysfs.c
@@ -8,6 +8,7 @@
 #include <linux/pci.h>
 #include <linux/sysfs.h>
 
+#include "regs/xe_regs.h"
 #include "xe_device.h"
 #include "xe_device_sysfs.h"
 #include "xe_mmio.h"
@@ -264,6 +265,35 @@ static const struct attribute_group auto_link_downgrade_attr_group = {
 	.attrs = auto_link_downgrade_attrs,
 };
 
+/**
+ * DOC: device_uuid
+ *
+ * Each Xe device exposes a 64-bit UUID that uniquely identifies the SoC.
+ * The value is read from the CRI_DEVICE_UUID register and can be
+ * read back through the ``device_uuid`` sysfs entry.
+ *
+ *    $ cat /sys/bus/pci/devices/<bdf>/device_uuid
+ */
+
+static ssize_t
+device_uuid_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct pci_dev *pdev = to_pci_dev(dev);
+	struct xe_device *xe = pdev_to_xe_device(pdev);
+
+	return sysfs_emit(buf, "%016llx\n", xe->device_uuid);
+}
+static DEVICE_ATTR_RO(device_uuid);
+
+static struct attribute *device_uuid_attrs[] = {
+	&dev_attr_device_uuid.attr,
+	NULL
+};
+
+static const struct attribute_group device_uuid_attr_group = {
+	.attrs = device_uuid_attrs,
+};
+
 int xe_device_sysfs_init(struct xe_device *xe)
 {
 	struct device *dev = xe->drm.dev;
@@ -285,5 +315,11 @@ int xe_device_sysfs_init(struct xe_device *xe)
 			return ret;
 	}
 
+	if (xe->info.platform == XE_CRESCENTISLAND) {
+		ret = devm_device_add_group(dev, &device_uuid_attr_group);
+		if (ret)
+			return ret;
+	}
+
 	return 0;
 }
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 180d450a6deb..6fdd16eac906 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -257,6 +257,9 @@ struct xe_device {
 		bool oob_initialized;
 	} wa_active;
 
+	/** @device_uuid: unique 64-bit identifier read from CRI_DEVICE_UUID */
+	u64 device_uuid;
+
 	/** @survivability: survivability information for device */
 	struct xe_survivability survivability;
 
-- 
2.54.0