[Intel-gfx] [PATCH 18/21] drm/i915/gt: Add timeline "mode"

[Matthew Brost]

On Thu, Dec 10, 2020 at 08:02:37AM +0000, Chris Wilson wrote:
> Explicitly differentiate between the absolute and relative timelines,
> and the global HWSP and ppHWSP relative offsets. When using a timeline
> that is relative to a known status page, we can replace the absolute
> addressing in the commands with indexed variants.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/gt/intel_timeline.c      | 21 ++++++++++++++++---
>  drivers/gpu/drm/i915/gt/intel_timeline.h      |  2 +-
>  .../gpu/drm/i915/gt/intel_timeline_types.h    | 10 +++++++--
>  3 files changed, 27 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.c b/drivers/gpu/drm/i915/gt/intel_timeline.c
> index cb20fcbb326b..da0a9659557a 100644
> --- a/drivers/gpu/drm/i915/gt/intel_timeline.c
> +++ b/drivers/gpu/drm/i915/gt/intel_timeline.c
> @@ -229,7 +229,6 @@ static int intel_timeline_init(struct intel_timeline *timeline,
>  
>  	timeline->gt = gt;
>  
> -	timeline->has_initial_breadcrumb = !hwsp;
>  	timeline->hwsp_cacheline = NULL;
>  
>  	if (!hwsp) {
> @@ -246,13 +245,29 @@ static int intel_timeline_init(struct intel_timeline *timeline,
>  			return PTR_ERR(cl);
>  		}
>  
> +		timeline->mode = INTEL_TIMELINE_ABSOLUTE;
>  		timeline->hwsp_cacheline = cl;
>  		timeline->hwsp_offset = cacheline * CACHELINE_BYTES;
>  
>  		vaddr = page_mask_bits(cl->vaddr);
>  	} else {
> -		timeline->hwsp_offset = offset;
> -		vaddr = i915_gem_object_pin_map(hwsp->obj, I915_MAP_WB);
> +		int preferred;
> +
> +		if (offset & INTEL_TIMELINE_CONTEXT) {
> +			timeline->mode = INTEL_TIMELINE_CONTEXT;
> +			timeline->hwsp_offset =
> +				offset & ~INTEL_TIMELINE_CONTEXT;
> +			preferred = i915_coherent_map_type(gt->i915);
> +		} else {
> +			timeline->mode = INTEL_TIMELINE_GLOBAL;
> +			timeline->hwsp_offset = offset;
> +			preferred = I915_MAP_WB;
> +		}
> +
> +		vaddr = i915_gem_object_pin_map(hwsp->obj,
> +						preferred | I915_MAP_OVERRIDE);
> +		if (IS_ERR(vaddr))
> +			vaddr = i915_gem_object_pin_map(hwsp->obj, I915_MAP_WC);
>  		if (IS_ERR(vaddr))
>  			return PTR_ERR(vaddr);
>  	}
> diff --git a/drivers/gpu/drm/i915/gt/intel_timeline.h b/drivers/gpu/drm/i915/gt/intel_timeline.h
> index deb71a8dbd43..69250de3a814 100644
> --- a/drivers/gpu/drm/i915/gt/intel_timeline.h
> +++ b/drivers/gpu/drm/i915/gt/intel_timeline.h
> @@ -76,7 +76,7 @@ static inline void intel_timeline_put(struct intel_timeline *timeline)
>  static inline bool
>  intel_timeline_has_initial_breadcrumb(const struct intel_timeline *tl)
>  {
> -	return tl->has_initial_breadcrumb;
> +	return tl->mode == INTEL_TIMELINE_ABSOLUTE;
>  }
>  
>  static inline int __intel_timeline_sync_set(struct intel_timeline *tl,
> diff --git a/drivers/gpu/drm/i915/gt/intel_timeline_types.h b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
> index f187c5aac11c..32c51425a0c4 100644
> --- a/drivers/gpu/drm/i915/gt/intel_timeline_types.h
> +++ b/drivers/gpu/drm/i915/gt/intel_timeline_types.h
> @@ -20,6 +20,12 @@ struct i915_syncmap;
>  struct intel_gt;
>  struct intel_timeline_hwsp;
>  
> +enum intel_timeline_mode {
> +	INTEL_TIMELINE_ABSOLUTE = 0,
> +	INTEL_TIMELINE_CONTEXT = BIT(0),
> +	INTEL_TIMELINE_GLOBAL = BIT(1),
> +};
> +

Not sure I like these names.

How about:
INTEL_TIMELINE_ABSOLUTE_GGTT
INTEL_TIMELINE_RELATIVE_PPGTT
INTEL_TIMELINE_RELATIVE_GGTT

Also not convinced we need the 'RELATIVE' modes. See my comments in 'Use
indices for writing into relative'.

Matt

>  struct intel_timeline {
>  	u64 fence_context;
>  	u32 seqno;
> @@ -45,6 +51,8 @@ struct intel_timeline {
>  	atomic_t pin_count;
>  	atomic_t active_count;
>  
> +	enum intel_timeline_mode mode;
> +
>  	const u32 *hwsp_seqno;
>  	struct i915_vma *hwsp_ggtt;
>  	u32 hwsp_offset;
> @@ -52,8 +60,6 @@ struct intel_timeline {
>  
>  	struct intel_timeline_cacheline *hwsp_cacheline;
>  
> -	bool has_initial_breadcrumb;
> -
>  	/**
>  	 * List of breadcrumbs associated with GPU requests currently
>  	 * outstanding.
> -- 
> 2.20.1
> 
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