[Intel-xe] [PATCH 1/2] drm/xe: Stash GMD_ID value in xe_gt

[Lucas De Marchi]

On Wed, Dec 06, 2023 at 12:50:36PM -0800, Matt Roper wrote:
>Although we've stored the major and minor versions for graphics/media in
>xe_device, it will be simpler to implement the uapi version query if we
>also stash the raw register value in the GT itself.
>
>Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
>---
> drivers/gpu/drm/xe/xe_gt.c       | 6 ++++++
> drivers/gpu/drm/xe/xe_gt_types.h | 2 ++
> 2 files changed, 8 insertions(+)
>
>diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
>index 154d6c7072b9..c6f7885ffdc0 100644
>--- a/drivers/gpu/drm/xe/xe_gt.c
>+++ b/drivers/gpu/drm/xe/xe_gt.c
>@@ -381,6 +381,12 @@ static int gt_fw_domain_init(struct xe_gt *gt)
> 	/* Initialize CCS mode sysfs after early initialization of HW engines */
> 	xe_gt_ccs_mode_sysfs_init(gt);
>
>+	/*
>+	 * Stash hardware-reported version.  Since this register does not exist
>+	 * on pre-MTL platforms, reading it there will (correctly) return 0.
>+	 */
>+	gt->info.gmdid = xe_mmio_read32(gt, GMD_ID);

I was coincidentally reading the PICA_DEVICE_ID for a debug (that we
currently don't read) and stumbled upon this.

I'm wondering what's the correct place to read and save the GMDIDs. We
already read it on xe_pci.c:handle_gmdid(). Why don't we simply stash it
there? With the current design, it doesn't seem we allow 2 GTs with
different graphics / media version since it still on the xe side
initialization.

So, why don't we just stash it on xe rather than GT?

Lucas De Marchi

>+
> 	err = xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
> 	XE_WARN_ON(err);
> 	xe_device_mem_access_put(gt_to_xe(gt));
>diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
>index 4e48c4643163..4e7a4494a554 100644
>--- a/drivers/gpu/drm/xe/xe_gt_types.h
>+++ b/drivers/gpu/drm/xe/xe_gt_types.h
>@@ -117,6 +117,8 @@ struct xe_gt {
> 		 * hwconfig blob.
> 		 */
> 		u64 __engine_mask;
>+		/** @gmdid: raw GMD_ID value from hardware */
>+		u32 gmdid;
> 	} info;
>
> 	/**
>-- 
>2.43.0
>