[PATCH] drm/xe: Add assert for XE_WA() usage

[Upadhyay, Tejas]

> -----Original Message-----
> From: De Marchi, Lucas <lucas.demarchi at intel.com>
> Sent: Tuesday, July 16, 2024 8:07 PM
> To: intel-xe at lists.freedesktop.org
> Cc: Upadhyay, Tejas <tejas.upadhyay at intel.com>; De Marchi, Lucas
> <lucas.demarchi at intel.com>
> Subject: [PATCH] drm/xe: Add assert for XE_WA() usage
> 
> It's not always safe to call XE_WA() in the driver initialization. Add a
> xe_gt_assert() so this doesn't go unnoticed.
> 
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_types.h | 6 ++++++
>  drivers/gpu/drm/xe/xe_wa.c       | 2 ++
>  drivers/gpu/drm/xe/xe_wa.h       | 7 ++++++-
>  3 files changed, 14 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_types.h
> b/drivers/gpu/drm/xe/xe_gt_types.h
> index 38a0d0e178c8..1e790ca0be43 100644
> --- a/drivers/gpu/drm/xe/xe_gt_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_types.h
> @@ -378,6 +378,12 @@ struct xe_gt {
>  		unsigned long *lrc;
>  		/** @wa_active.oob: bitmap with active OOB workaroudns
> */
>  		unsigned long *oob;
> +		/**
> +		 * @wa_active.oob: mark oob as initialized to help detecting

s/ wa_active.oob /wa_active.oob_initialized

> +		 * misuse of XE_WA() - it can only be called on initialization
> +		 * after OOB WAs have being processed
> +		 */
> +		bool oob_initialized;
>  	} wa_active;
> 
>  	/** @user_engines: engines present in GT and available to userspace
> */ diff --git a/drivers/gpu/drm/xe/xe_wa.c b/drivers/gpu/drm/xe/xe_wa.c
> index fd009b2c68fa..de356c024d5d 100644
> --- a/drivers/gpu/drm/xe/xe_wa.c
> +++ b/drivers/gpu/drm/xe/xe_wa.c
> @@ -755,6 +755,7 @@ void xe_wa_process_oob(struct xe_gt *gt)
> 
>  	xe_rtp_process_ctx_enable_active_tracking(&ctx, gt->wa_active.oob,
>  						  ARRAY_SIZE(oob_was));
> +	gt->wa_active.oob_initialized = true;
>  	xe_rtp_process(&ctx, oob_was);
>  }
> 
> @@ -838,6 +839,7 @@ int xe_wa_init(struct xe_gt *gt)
>  	gt->wa_active.lrc = p;
>  	p += n_lrc;
>  	gt->wa_active.oob = p;
> +	gt->wa_active.oob_initialized = false;

Before this init, mmio read in xe_mmio_probe_tiles() will hit in some case, right? I think gt->wa_active.oob_initialized automatically default to false by kzalloc, do will need to set here?

> 
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_wa.h b/drivers/gpu/drm/xe/xe_wa.h index
> db9ddeaf69bf..52337405b5bc 100644
> --- a/drivers/gpu/drm/xe/xe_wa.h
> +++ b/drivers/gpu/drm/xe/xe_wa.h
> @@ -6,6 +6,8 @@
>  #ifndef _XE_WA_
>  #define _XE_WA_
> 
> +#include "xe_assert.h"
> +
>  struct drm_printer;
>  struct xe_gt;
>  struct xe_hw_engine;
> @@ -25,6 +27,9 @@ void xe_wa_dump(struct xe_gt *gt, struct drm_printer
> *p);
>   * @gt__: gt instance
>   * @id__: XE_OOB_<id__>, as generated by build system in
> generated/xe_wa_oob.h
>   */
> -#define XE_WA(gt__, id__) test_bit(XE_WA_OOB_ ## id__, (gt__)-
> >wa_active.oob)
> +#define XE_WA(gt__, id__) ({						\
> +	xe_gt_assert(gt__, (gt__)->wa_active.oob_initialized);		\
> +	test_bit(XE_WA_OOB_ ## id__, (gt__)->wa_active.oob);		\
> +})
> 
>  #endif
> --
> 2.43.0