[Intel-gfx] [PATCH v3 07/11] drm/i915/dsb: functions to enable/disable DSB engine.

[Sharma, Shashank]

On 8/28/2019 12:40 AM, Animesh Manna wrote:
> DSB will be used for performance improvement for some special scenario.
> DSB engine will be enabled based on need and after completion of its work
> will be disabled. Api added for enable/disable operation by using DSB_CTRL
> register.
>
> Cc: Michel Thierry <michel.thierry at intel.com>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_dsb.c | 40 ++++++++++++++++++++++++
>   1 file changed, 40 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
> index d36ee8244427..2d6e78868f2d 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -33,6 +33,46 @@ static inline bool is_dsb_busy(struct intel_dsb *dsb)
>   	return DSB_STATUS & I915_READ(DSB_CTRL(pipe, dsb->id));
>   }
>   
> +static bool intel_dsb_enable_engine(struct intel_dsb *dsb)
> +{
> +	struct intel_crtc *crtc = dsb->crtc;
> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> +	enum pipe pipe = crtc->pipe;
> +	u32 dsb_ctrl;
> +
> +	dsb_ctrl = I915_READ(DSB_CTRL(pipe, dsb->id));
> +
> +	if (DSB_STATUS & dsb_ctrl) {
> +		DRM_DEBUG_KMS("DSB engine is busy.\n");
> +		return false;
> +	}
> +
> +	dsb_ctrl |= DSB_ENABLE;
> +	I915_WRITE(DSB_CTRL(pipe, dsb->id), dsb_ctrl);
readback DSB status and confirm if that's really enabled ?
> +
> +	return true;
> +}
> +
> +static bool intel_dsb_disable_engine(struct intel_dsb *dsb)
> +{
> +	struct intel_crtc *crtc = dsb->crtc;
> +	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> +	enum pipe pipe = crtc->pipe;
> +	u32 dsb_ctrl;
> +
> +	dsb_ctrl = I915_READ(DSB_CTRL(pipe, dsb->id));
> +
> +	if (DSB_STATUS & dsb_ctrl) {
> +		DRM_DEBUG_KMS("DSB engine is busy.\n");
> +		return false;
> +	}
> +
> +	dsb_ctrl &= ~DSB_ENABLE;
> +	I915_WRITE(DSB_CTRL(pipe, dsb->id), dsb_ctrl);
> +

Same as above.

- Shashank

> +	return true;
> +}
> +
>   struct intel_dsb *
>   intel_dsb_get(struct intel_crtc *crtc)
>   {