Re: [v2,10/10] drm/xe/vsec: Update PMT internal access for CRI

On 13-08-2026 01:07, Michael J. Ruhl <[email protected]> wrote:
> Xe access the PMT infrastructure directly. The current usage
> is supported ONLY by BMG devices.
>
> CRI has further requirements for access.
>
> Add a new API to access the GUID based on the platform.
> Use the API get the GUID for each device.
>
> Signed-off-by: Michael J. Ruhl<[email protected]>
> ---
>   drivers/gpu/drm/xe/regs/xe_pmt.h |  4 +++-
>   drivers/gpu/drm/xe/xe_debugfs.c  | 30 +++++++++++++-----------
>   drivers/gpu/drm/xe/xe_hwmon.c    | 10 ++++++--
>   drivers/gpu/drm/xe/xe_pcode.c    | 10 ++++++--
>   drivers/gpu/drm/xe/xe_vsec.c     | 40 ++++++++++++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_vsec.h     |  1 +
>   6 files changed, 77 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/regs/xe_pmt.h b/drivers/gpu/drm/xe/regs/xe_pmt.h
> index fc9c9cb6a830..683bf401dc9d 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)
> @@ -25,6 +25,8 @@
>   #define CRI_DISCOVERY_OFFSET           (SOC_BASE + CRI_TELEMETRY_BASE_OFFSET)
>   #define CRI_TELEMETRY_OFFSET           (SOC_BASE + CRI_TELEMETRY_BASE_OFFSET)
>
> +#define CRI_PUNIT_TELEMETRY_GUID       XE_REG(CRI_DISCOVERY_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 eeceab4a9901..67903c854562 100644
> --- a/drivers/gpu/drm/xe/xe_debugfs.c
> +++ b/drivers/gpu/drm/xe/xe_debugfs.c
> @@ -97,11 +97,16 @@ 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;
> +       u32 guid;
>          int ret;
>
> -       ret = xe_pmt_telem_read(xe->drm.dev,
> -                               xe_mmio_read32(mmio, PUNIT_TELEMETRY_GUID),
> -                               &residency, offset, sizeof(residency));
> +       guid = xe_vsec_get_guid(xe);
> +       if (!guid) {
> +               drm_warn(&xe->drm, "PMT device is not powered\n");
> +               return;
> +       }
Instead of reading the GUID for every residency counter access, can 
|xe_vsec| read it once after OCODE is loaded and then use the cached 
value internally when |xe_pmt_telem_read()| is called?

> +
> +       ret = xe_pmt_telem_read(xe->drm.dev, guid, &residency, offset, sizeof(residency));
>          if (ret != sizeof(residency)) {
>                  drm_warn(&xe->drm, "%s counter failed to read, ret %d\n", name, ret);
>                  return;
> @@ -706,23 +711,22 @@ void xe_debugfs_register(struct xe_device *xe)
>                                   ARRAY_SIZE(debugfs_list),
>                                   root, minor);
>
> -       if (xe->info.platform == XE_BATTLEMAGE && !IS_SRIOV_VF(xe)) {
> -               drm_debugfs_create_files(debugfs_residencies,
> -                                        ARRAY_SIZE(debugfs_residencies),
> -                                        root, minor);
> -       }
> -
>          /*
> -        * Pcode version read from PMT is currently only supported on CRI and BMG platforms in PF
> -        * mode, as both platforms support the necessary telemetry read mechanism and have a fixed
> -        * PUNIT_VERSION_OFFSET.
> +        * Residencies and Pcode version read from PMT is currently only supported on CRI and BMG
> +        * platforms in PF mode.  Both platforms support the necessary telemetry read mechanism
> +        * and have a fixed offses for the required data.
offset*
>           * Attempting this access on other platforms must be verified before enabling support.
>           */
>          if (!IS_SRIOV_VF(xe) &&
> -           (xe->info.platform == XE_CRESCENTISLAND || xe->info.platform == XE_BATTLEMAGE))
> +           (xe->info.platform == XE_CRESCENTISLAND || xe->info.platform == XE_BATTLEMAGE)) {
> +               drm_debugfs_create_files(debugfs_residencies,
> +                                        ARRAY_SIZE(debugfs_residencies),
> +                                        root, minor);
> +
>                  drm_debugfs_create_files(pcode_info_debugfs,
>                                           ARRAY_SIZE(pcode_info_debugfs),
>                                           root, minor);
> +       }
>
>          debugfs_create_file("forcewake_all", 0400, root, xe,
>                              &forcewake_all_fops);
> diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
> index 49f7e0edcc4b..db48594fcc1f 100644
> --- a/drivers/gpu/drm/xe/xe_hwmon.c
> +++ b/drivers/gpu/drm/xe/xe_hwmon.c
> @@ -517,9 +517,15 @@ xe_hwmon_energy_get(struct xe_hwmon *hwmon, int channel, long *energy)
>
>          if (hwmon->xe->info.platform == XE_BATTLEMAGE) {
>                  u64 pmt_val;
> +               u32 guid;
>
> -               ret = xe_pmt_telem_read(hwmon->xe->drm.dev,
> -                                       xe_mmio_read32(mmio, PUNIT_TELEMETRY_GUID),
> +               guid = xe_vsec_get_guid(hwmon->xe);
> +               if (!guid) {
> +                       drm_warn(&hwmon->xe->drm, "PMT device is not powered\n");
> +                       *energy = 0;
> +                       return;
> +               }
same as above
> +               ret = xe_pmt_telem_read(hwmon->xe->drm.dev, 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 ccc3bdeed6bb..1b93fda1f41a 100644
> --- a/drivers/gpu/drm/xe/xe_pcode.c
> +++ b/drivers/gpu/drm/xe/xe_pcode.c
> @@ -368,11 +368,17 @@ ALLOW_ERROR_INJECTION(xe_pcode_probe_early, ERRNO); /* See xe_pci_probe */
>   int xe_get_pcode_version(struct xe_device *xe, struct xe_pcode_version *version)
>   {
>          int ret = 0;
> +       u32 guid;
>
>          guard(xe_pm_runtime)(xe);
>
> -       ret = xe_pmt_telem_read(xe->drm.dev,
> -                               xe_mmio_read32(xe_root_tile_mmio(xe), PUNIT_TELEMETRY_GUID),
> +       guid = xe_vsec_get_guid(xe);
> +       if (!guid) {
> +               xe_warn(xe, "PMT device is not powered\n");
> +               return -ENODATA;
> +       }
> +
> +       ret = xe_pmt_telem_read(xe->drm.dev, 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 bed5103dac19..a56f988d13eb 100644
> --- a/drivers/gpu/drm/xe/xe_vsec.c
> +++ b/drivers/gpu/drm/xe/xe_vsec.c
> @@ -565,6 +565,46 @@ static void vsec_disable_late_bind_work(void *arg)
>                  xe_pm_runtime_put(xe);
>   }
>
> +u32 xe_vsec_get_guid(struct xe_device *xe)
> +{
> +       struct xe_mmio *mmio = xe_root_tile_mmio(xe);
> +       u32 guid;
> +
> +       /*
> +        * Both supported platforms (BMG, CRI) require the remapper callback to
> +        * access data. CRI needs it for the GUID.
> +        */
> +       if (!xe->soc_remapper.set_telem_region)
> +               return 0;
> +
> +       /* caller must ensure correct power state */
> +       if (!xe_pm_runtime_get_if_active(xe))
> +               return 0;
> +
> +       mutex_lock(&xe->pmt.lock);
> +
> +       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);
> +               break;
> +       }
> +
> +       mutex_unlock(&xe->pmt.lock);
> +       xe_pm_runtime_put(xe);
> +
> +       return guid;
> +}
> +
>   /**
>    * 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..43c3e9f227c5 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);
> +u32 xe_vsec_get_guid(struct xe_device *xe);
>   int xe_pmt_telem_read(struct device *dev, u32 guid, u64 *data, loff_t user_offset, u32 count);
>