[Intel-gfx] [PATCH 25/49] drm/i915/bxt: Add DDI hpd handler

[Daniel Vetter]

On Tue, Mar 17, 2015 at 11:39:51AM +0200, Imre Deak wrote:
> From: Shashank Sharma <shashank.sharma at intel.com>
> 
> This patch adds a hot plug interrupt handler function for BXT.
> What this function typically does is:
> 1. Check if hot plug is enabled from hot plug control register.
> 2. Call hpd_irq_handler with appropriate trigger to detect a
>    plug storm and schedule a bottom half.
> 3. Clear sticky status bits in hot plug control register..
> 
> Reviewed-by: Satheeshakrishna M <satheeshakrishna.m at intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
> ---
>  drivers/gpu/drm/i915/i915_irq.c | 45 +++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 43 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index a51c00e..4a2f85b 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -2227,6 +2227,38 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
>  	return ret;
>  }
>  
> +static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
> +{
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	uint32_t hp_control;
> +	uint32_t hp_trigger;
> +
> +	/* Get the status */
> +	hp_trigger = iir_status & BXT_DE_PORT_HOTPLUG_MASK;
> +	hp_control = I915_READ(BXT_HOTPLUG_CTL);
> +
> +	/* Hotplug not enabled ? */
> +	if (unlikely(!(hp_control & BXT_HOTPLUG_CTL_MASK))) {
> +		DRM_ERROR("Interrupt when HPD disabled\n");
> +		return;
> +	}
> +
> +	DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
> +		hp_control & BXT_HOTPLUG_CTL_MASK);
> +
> +	/* Check for HPD storm and schedule bottom half */
> +	intel_hpd_irq_handler(dev, hp_trigger, hp_control, hpd_bxt);
> +
> +	/*
> +	 * Todo: Save the hot plug status for bottom half before
> +	 * clearing the sticky status bits, else the status will be
> +	 * lost.
> +	 */

This seems to be ok, but code to handle long/short pulse in
intel_hpd_irq_handler seems to be missing. And we absolutely need that for
mst ports (I guess bxt has those?).
-Daniel

> +
> +	/* Clear sticky bits in hpd status */
> +	I915_WRITE(BXT_HOTPLUG_CTL, hp_control);
> +}
> +
>  static irqreturn_t gen8_irq_handler(int irq, void *arg)
>  {
>  	struct drm_device *dev = arg;
> @@ -2236,6 +2268,7 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
>  	uint32_t tmp = 0;
>  	enum pipe pipe;
>  	u32 aux_mask = GEN8_AUX_CHANNEL_A;
> +	bool found = false;
>  
>  	if (!intel_irqs_enabled(dev_priv))
>  		return IRQ_NONE;
> @@ -2276,9 +2309,17 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
>  			I915_WRITE(GEN8_DE_PORT_IIR, tmp);
>  			ret = IRQ_HANDLED;
>  
> -			if (tmp & aux_mask)
> +			if (tmp & aux_mask) {
>  				dp_aux_irq_handler(dev);
> -			else
> +				found = true;
> +			}
> +
> +			if (tmp & BXT_DE_PORT_HOTPLUG_MASK) {
> +				bxt_hpd_handler(dev, tmp);
> +				found = true;
> +			}
> +
> +			if (!found)
>  				DRM_ERROR("Unexpected DE Port interrupt\n");
>  		}
>  		else
> -- 
> 2.1.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch