[PATCH v2 05/11] drm/i915/dsb: add intel_dsb_gosub_finish()

[Shankar, Uma]

> -----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 v2 05/11] drm/i915/dsb: add intel_dsb_gosub_finish()
> 
> A DSB buffer which will be used for GOSUB execution does not need the DEWAKE
> mechanism but still need to be 64 bit aligned. Add helper to finish preparation of
> a dsb buffer to be executed with GOSUB instruction.
> 
> v2: Add a cacheline of noops at the end of GOSUB buffer (Ville)

Changes Look Good to me.
Reviewed-by: Uma Shankar <uma.shankar at intel.com>

> Signed-off-by: Chaitanya Kumar Borah <chaitanya.kumar.borah at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dsb.c | 13 +++++++++++++
> drivers/gpu/drm/i915/display/intel_dsb.h |  1 +
>  2 files changed, 14 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c
> b/drivers/gpu/drm/i915/display/intel_dsb.c
> index 2cda6fc7857b..97ea3c655590 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -585,6 +585,19 @@ void intel_dsb_gosub(struct intel_dsb *dsb,
>  	intel_dsb_align_tail(dsb);
>  }
> 
> +void intel_dsb_gosub_finish(struct intel_dsb *dsb) {
> +	intel_dsb_align_tail(dsb);
> +
> +	/*
> +	 * "All subroutines called by the GOSUB instruction
> +	 *  must end with a cacheline of NOPs"
> +	 */
> +	intel_dsb_noop(dsb, 8);
> +
> +	intel_dsb_buffer_flush_map(&dsb->dsb_buf);
> +}
> +
>  void intel_dsb_finish(struct intel_dsb *dsb)  {
>  	struct intel_crtc *crtc = dsb->crtc;
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h
> b/drivers/gpu/drm/i915/display/intel_dsb.h
> index 8b2cf0a7b7e6..6900acd603b8 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.h
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.h
> @@ -31,6 +31,7 @@ struct intel_dsb *intel_dsb_prepare(struct
> intel_atomic_state *state,
>  				    enum intel_dsb_id dsb_id,
>  				    unsigned int max_cmds);
>  void intel_dsb_finish(struct intel_dsb *dsb);
> +void intel_dsb_gosub_finish(struct intel_dsb *dsb);
>  void intel_dsb_cleanup(struct intel_dsb *dsb);  void intel_dsb_reg_write(struct
> intel_dsb *dsb,
>  			 i915_reg_t reg, u32 val);
> --
> 2.25.1