Re: [PATCH v5 16/18] drm/xe/vsec: Add PMT GUID internal access

["Poosa, Karthik" <karthik.poosa@intel.com>]

On 04-09-2026 01:40, Michael J. Ruhl wrote:
> Xe accesses the PMT infrastructure directly. The current usage is
> supported ONLY by BMG devices.
>
> CRI has further requirements for access.
>
> Add the platform id to the GUID register define and use that for the
> register access.
>
> Add an API to allow access the GUID based on the platform.
>
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
> ---
>   drivers/gpu/drm/xe/regs/xe_pmt.h     |  4 ++-
>   drivers/gpu/drm/xe/xe_debugfs.c      |  3 +-
>   drivers/gpu/drm/xe/xe_device_types.h |  2 ++
>   drivers/gpu/drm/xe/xe_hwmon.c        |  2 +-
>   drivers/gpu/drm/xe/xe_pcode.c        |  2 +-
>   drivers/gpu/drm/xe/xe_vsec.c         | 44 ++++++++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_vsec.h         |  1 +
>   7 files changed, 54 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/regs/xe_pmt.h b/drivers/gpu/drm/xe/regs/xe_pmt.h
> index 2f6658395587..fb5b5a8648ba 100644
> --- a/drivers/gpu/drm/xe/regs/xe_pmt.h
> +++ b/drivers/gpu/drm/xe/regs/xe_pmt.h
> @@ -10,7 +10,7 @@
>   #define BMG_PMT_BASE_OFFSET		0xDB000
>   #define BMG_DISCOVERY_OFFSET		(SOC_BASE + BMG_PMT_BASE_OFFSET)
>   
> -#define PUNIT_TELEMETRY_GUID		XE_REG(BMG_DISCOVERY_OFFSET + 0x4)
> +#define BMG_PUNIT_TELEMETRY_GUID	XE_REG(BMG_DISCOVERY_OFFSET + 0x4)
>   #define BMG_ENERGY_STATUS_PMT_OFFSET	(0x30)
>   #define	ENERGY_PKG			REG_GENMASK64(31, 0)
>   #define	ENERGY_CARD			REG_GENMASK64(63, 32)
> @@ -24,6 +24,8 @@
>   /* for CRI discovery and telemetry are in an indexed window */
>   #define CRI_PMT_OFFSET			(SOC_BASE + XE_PMT_BASE_OFFSET)
>   
> +#define CRI_PUNIT_TELEMETRY_GUID	XE_REG(CRI_PMT_OFFSET + 0x4)
> +
>   #define BMG_MODS_RESIDENCY_OFFSET		(0x4D0)
>   #define BMG_G2_RESIDENCY_OFFSET		(0x530)
>   #define BMG_G6_RESIDENCY_OFFSET		(0x538)
> diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
> index 28135f84e286..b01f1e649b51 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> @@ -101,10 +101,11 @@ static void read_residency_counter(struct xe_device *xe, struct xe_mmio *mmio,
>   				   u32 offset, const char *name, struct drm_printer *p)
>   {
>   	u64 residency = 0;
> +
this can be removed
>   	int ret;
>   
>   	ret = xe_pmt_telem_read(xe->drm.dev,
> -				xe_mmio_read32(mmio, PUNIT_TELEMETRY_GUID),
> +				xe_mmio_read32(mmio, BMG_PUNIT_TELEMETRY_GUID),
>   				&residency, offset, sizeof(residency));
>   	if (ret != sizeof(residency)) {
>   		drm_warn(&xe->drm, "%s counter failed to read, ret %d\n", name, ret);
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index 69e052ac5a82..2a8c519e1639 100644
> --- a/drivers/gpu/drm/xe/xe_device_types.h
> +++ b/drivers/gpu/drm/xe/xe_device_types.h
> @@ -473,6 +473,8 @@ struct xe_device {
>   		struct delayed_work work;
>   		/** @pmt.retry_count: late-bind probe retry */
>   		u32 retry_count;
> +		/** @pmt.punit_guid_cache: cache of the PUINT GUID */
> +		u32 punit_guid_cache;
>   	} pmt;
>   
>   	/** @soc_remapper: SoC remapper object */
> diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
> index 5284cab6703d..b9740224e07f 100644
> --- a/drivers/gpu/drm/xe/xe_hwmon.c
> +++ b/drivers/gpu/drm/xe/xe_hwmon.c
> @@ -519,7 +519,7 @@ xe_hwmon_energy_get(struct xe_hwmon *hwmon, int channel, long *energy)
>   		u64 pmt_val;
>   
>   		ret = xe_pmt_telem_read(hwmon->xe->drm.dev,
> -					xe_mmio_read32(mmio, PUNIT_TELEMETRY_GUID),
> +					xe_mmio_read32(mmio, BMG_PUNIT_TELEMETRY_GUID),
>   					&pmt_val, BMG_ENERGY_STATUS_PMT_OFFSET,	sizeof(pmt_val));
>   		if (ret != sizeof(pmt_val)) {
>   			drm_warn(&hwmon->xe->drm, "energy read from pmt failed, ret %d\n", ret);
> diff --git a/drivers/gpu/drm/xe/xe_pcode.c b/drivers/gpu/drm/xe/xe_pcode.c
> index d502205bb72a..844d8c6face6 100644
> --- a/drivers/gpu/drm/xe/xe_pcode.c
> +++ b/drivers/gpu/drm/xe/xe_pcode.c
> @@ -369,7 +369,7 @@ int xe_get_pcode_version(struct xe_device *xe, struct xe_pcode_version *version)
>   	guard(xe_pm_runtime)(xe);
>   
>   	ret = xe_pmt_telem_read(xe->drm.dev,
> -				xe_mmio_read32(xe_root_tile_mmio(xe), PUNIT_TELEMETRY_GUID),
> +				xe_mmio_read32(xe_root_tile_mmio(xe), BMG_PUNIT_TELEMETRY_GUID),
>   				(u64 *)version, PUNIT_VERSION_OFFSET, sizeof(*version));
>   	if (ret != sizeof(*version)) {
>   		xe_warn(xe, "pcode version read from PMT failed, ret %pe\n", ERR_PTR(ret));
> diff --git a/drivers/gpu/drm/xe/xe_vsec.c b/drivers/gpu/drm/xe/xe_vsec.c
> index 48cacd23b071..896dfb011baf 100644
> --- a/drivers/gpu/drm/xe/xe_vsec.c
> +++ b/drivers/gpu/drm/xe/xe_vsec.c
> @@ -566,6 +566,50 @@ static void vsec_disable_late_bind_work(void *arg)
>   		xe_pm_runtime_put(xe);
>   }
>   
> +int xe_vsec_get_guid(struct xe_device *xe, u32 *guid)
> +{
> +	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
> +	int ret = 0;
> +
> +	if (IS_SRIOV_VF(xe))
> +		return -EINVAL;
> +
> +	if (!xe_pm_runtime_get_if_active(xe))
> +		return -ENODATA;
> +
> +	mutex_lock(&xe->pmt.lock);
> +
> +	if (xe->pmt.punit_guid_cache) {
> +		*guid = xe->pmt.punit_guid_cache;
> +		goto unlock;
> +	}
can you add a comment here that guid doesn't change after first read.
> +
> +	switch (xe->info.platform) {
> +	case XE_BATTLEMAGE:
> +		*guid = xe_mmio_read32(mmio, BMG_PUNIT_TELEMETRY_GUID);
> +		break;
> +
> +	case XE_CRESCENTISLAND:
> +		xe->soc_remapper.set_telem_region(xe, CRI_IDX_TELEM_DISCOVERY);
> +		*guid = xe_mmio_read32(mmio, CRI_PUNIT_TELEMETRY_GUID);
> +		break;
> +
> +	default:
> +		*guid = 0;
> +		drm_err(&xe->drm, "Unsupported platform: %u\n", xe->info.platform);
> +		ret = -EINVAL;
> +		break;
> +	}
> +
> +	xe->pmt.punit_guid_cache = *guid;
you can set cache only when guid is valid

if(*guid)

    xe->pmt.punit_guid_cache = *guid;

> +
> +unlock:
> +	mutex_unlock(&xe->pmt.lock);
> +	xe_pm_runtime_put(xe);
> +
> +	return ret;
> +}
> +
>   /**
>    * xe_vsec_init - Initialize resources and add intel_vsec auxiliary
>    * interface
> diff --git a/drivers/gpu/drm/xe/xe_vsec.h b/drivers/gpu/drm/xe/xe_vsec.h
> index c4a1e2fc67d8..50187fdc1207 100644
> --- a/drivers/gpu/drm/xe/xe_vsec.h
> +++ b/drivers/gpu/drm/xe/xe_vsec.h
> @@ -10,6 +10,7 @@ struct device;
>   struct xe_device;
>   
>   int xe_vsec_init(struct xe_device *xe);
> +int xe_vsec_get_guid(struct xe_device *xe, u32 *guid);
>   int xe_pmt_telem_read(struct device *dev, u32 guid, u64 *data, loff_t user_offset, u32 count);
>   
>   #endif