[PATCH 03/11] drm/i915/dsb: Extract intel_dsb_{head,tail}()

[Manna, Animesh]

> -----Original Message-----
> From: Borah, Chaitanya Kumar <chaitanya.kumar.borah at intel.com>
> Sent: Tuesday, April 8, 2025 4:30 PM
> To: intel-xe at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
> Cc: ville.syrjala at linux.intel.com; Shankar, Uma <uma.shankar at intel.com>;
> Borah, Chaitanya Kumar <chaitanya.kumar.borah at intel.com>; Manna,
> Animesh <animesh.manna at intel.com>
> Subject: [PATCH 03/11] drm/i915/dsb: Extract intel_dsb_{head,tail}()
> 
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> Extract the code that calculates the DSB_HEAD/TAIL register values into small
> helpers. We already have two copies of this, and soon there will be a third.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Animesh Manna <animesh.manna at intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_dsb.c | 24 ++++++++++++++----------
>  1 file changed, 14 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> index 08e3bbea1a67..0de15e3a9a56 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -237,6 +237,16 @@ static bool is_dsb_busy(struct intel_display *display,
> enum pipe pipe,
>  	return intel_de_read_fw(display, DSB_CTRL(pipe, dsb_id)) &
> DSB_STATUS_BUSY;  }
> 
> +static unsigned int intel_dsb_head(struct intel_dsb *dsb) {
> +	return intel_dsb_buffer_ggtt_offset(&dsb->dsb_buf);
> +}
> +
> +static unsigned int intel_dsb_tail(struct intel_dsb *dsb) {
> +	return intel_dsb_buffer_ggtt_offset(&dsb->dsb_buf) + dsb->free_pos
> *
> +4; }
> +
>  static void intel_dsb_ins_align(struct intel_dsb *dsb)  {
>  	/*
> @@ -625,7 +635,6 @@ static void _intel_dsb_chain(struct intel_atomic_state
> *state,
>  	struct intel_display *display = to_intel_display(state->base.dev);
>  	struct intel_crtc *crtc = dsb->crtc;
>  	enum pipe pipe = crtc->pipe;
> -	u32 tail;
> 
>  	if (drm_WARN_ON(display->drm, dsb->id == chained_dsb->id))
>  		return;
> @@ -633,8 +642,6 @@ static void _intel_dsb_chain(struct intel_atomic_state
> *state,
>  	if (!assert_dsb_tail_is_aligned(chained_dsb))
>  		return;
> 
> -	tail = chained_dsb->free_pos * 4;
> -
>  	intel_dsb_reg_write(dsb, DSB_CTRL(pipe, chained_dsb->id),
>  			    ctrl | DSB_ENABLE);
> 
> @@ -655,10 +662,10 @@ static void _intel_dsb_chain(struct
> intel_atomic_state *state,
>  	}
> 
>  	intel_dsb_reg_write(dsb, DSB_HEAD(pipe, chained_dsb->id),
> -			    intel_dsb_buffer_ggtt_offset(&chained_dsb-
> >dsb_buf));
> +			    intel_dsb_head(chained_dsb));
> 
>  	intel_dsb_reg_write(dsb, DSB_TAIL(pipe, chained_dsb->id),
> -			    intel_dsb_buffer_ggtt_offset(&chained_dsb-
> >dsb_buf) + tail);
> +			    intel_dsb_tail(chained_dsb));
> 
>  	if (ctrl & DSB_WAIT_FOR_VBLANK) {
>  		/*
> @@ -703,13 +710,10 @@ static void _intel_dsb_commit(struct intel_dsb
> *dsb, u32 ctrl,
>  	struct intel_crtc *crtc = dsb->crtc;
>  	struct intel_display *display = to_intel_display(crtc->base.dev);
>  	enum pipe pipe = crtc->pipe;
> -	u32 tail;
> 
>  	if (!assert_dsb_tail_is_aligned(dsb))
>  		return;
> 
> -	tail = dsb->free_pos * 4;
> -
>  	if (is_dsb_busy(display, pipe, dsb->id)) {
>  		drm_err(display->drm, "[CRTC:%d:%s] DSB %d is busy\n",
>  			crtc->base.base.id, crtc->base.name, dsb->id); @@ -
> 727,7 +731,7 @@ static void _intel_dsb_commit(struct intel_dsb *dsb, u32
> ctrl,
>  			  dsb_error_int_en(display) | DSB_PROG_INT_EN);
> 
>  	intel_de_write_fw(display, DSB_HEAD(pipe, dsb->id),
> -			  intel_dsb_buffer_ggtt_offset(&dsb->dsb_buf));
> +			  intel_dsb_head(dsb));
> 
>  	if (hw_dewake_scanline >= 0) {
>  		int diff, position;
> @@ -749,7 +753,7 @@ static void _intel_dsb_commit(struct intel_dsb *dsb,
> u32 ctrl,
>  	}
> 
>  	intel_de_write_fw(display, DSB_TAIL(pipe, dsb->id),
> -			  intel_dsb_buffer_ggtt_offset(&dsb->dsb_buf) + tail);
> +			  intel_dsb_tail(dsb));
>  }
> 
>  /**
> --
> 2.25.1