Re: [PATCH v8 13/20] drm/xe/vsec: Add base_offset to allow for more flexibilty

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Sep 11, 2026 at 01:12:01PM -0700, Michael J. Ruhl wrote:
> Current pmt_telem_read() usage is a fixed (for BMG) offset.
> In order to support other devices this must be settable.
> 
> Add a base offset for more flexibility.
> Add a check to verify that it has been set before allowing
> device access.
> 
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

> ---
>  drivers/gpu/drm/xe/xe_device_types.h | 2 ++
>  drivers/gpu/drm/xe/xe_vsec.c         | 9 ++++++++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
> index 4661bfce2f4e..ebdc271ebeae 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 {
>  		/** @pmt.lock: protect access for telemetry data */
>  		struct mutex lock;
> +		/** @pmt.base_offset: device specific base offset */
> +		u64 base_offset;
>  	} pmt;
>  
>  	/** @soc_remapper: SoC remapper object */
> diff --git a/drivers/gpu/drm/xe/xe_vsec.c b/drivers/gpu/drm/xe/xe_vsec.c
> index ca8414441a69..856973473fd7 100644
> --- a/drivers/gpu/drm/xe/xe_vsec.c
> +++ b/drivers/gpu/drm/xe/xe_vsec.c
> @@ -173,14 +173,15 @@ static int xe_guid_decode(u32 guid, int *index, u32 *offset)
>   * Return:
>   * * -ENODEV device is not available (hotplug)
>   * * -EINVAL for VF and PMT WATCHER requests
> + * * -EAGAIN base_offset has not been set, so init path has not yet been done.
>   * * count   number of bytes read on success
>   */
>  int xe_pmt_telem_read(struct device *dev, u32 guid, u64 *data, loff_t user_offset,
>  		      u32 count)
>  {
>  	struct xe_device *xe = kdev_to_xe_device(dev);
> -	void __iomem *telem_addr = xe->mmio.regs + BMG_TELEMETRY_OFFSET;
>  	u32 cap_type = FIELD_GET(GUID_CAP_TYPE, guid);
> +	void __iomem *telem_addr = xe->mmio.regs + xe->pmt.base_offset;
>  	u32 mem_region;
>  	u32 offset;
>  	int ret = 0;
> @@ -194,6 +195,11 @@ int xe_pmt_telem_read(struct device *dev, u32 guid, u64 *data, loff_t user_offse
>  		goto dev_exit;
>  	}
>  
> +	if (!xe->pmt.base_offset) {
> +		ret = -EAGAIN;
> +		goto dev_exit;
> +	}
> +
>  	ret = xe_guid_decode(guid, &mem_region, &offset);
>  	if (ret)
>  		goto dev_exit;
> @@ -272,6 +278,7 @@ void xe_vsec_init(struct xe_device *xe)
>  	case XE_VSEC_BMG:
>  		if (IS_SRIOV_VF(xe))
>  			return;
> +		xe->pmt.base_offset = BMG_TELEMETRY_OFFSET;
>  		info->priv_data = &xe_pmt_cb;
>  		break;
>  	default:
> -- 
> 2.43.0
>