drm/i915: add POWER_DOMAIN_PLLS

And get/put it when needed. The special thing about this commit is
that it will now return false in ibx_pch_dpll_get_hw_state() in case
the power domain is not enabled. This will fix some WARNs we have when
we run pm_rpm on SNB.

Testcase: igt/pm_rpm
Bugzilla:https://bugs.freedesktop.org/show_bug.cgi?id=80463
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2043,6 +2043,8 @@ static const char *power_domain_str(enum intel_display_power_domain domain)
 		return "VGA";
 	case POWER_DOMAIN_AUDIO:
 		return "AUDIO";
+	case POWER_DOMAIN_PLLS:
+		return "PLLS";
 	case POWER_DOMAIN_INIT:
 		return "INIT";
 	default:

drivers/gpu/drm/i915/i915_drv.h

@@ -129,6 +129,7 @@ enum intel_display_power_domain {
 	POWER_DOMAIN_PORT_OTHER,
 	POWER_DOMAIN_VGA,
 	POWER_DOMAIN_AUDIO,
+	POWER_DOMAIN_PLLS,
 	POWER_DOMAIN_INIT,
 
 	POWER_DOMAIN_NUM,

drivers/gpu/drm/i915/intel_display.c

@@ -1814,6 +1814,8 @@ static void intel_enable_shared_dpll(struct intel_crtc *crtc)
 	}
 	WARN_ON(pll->on);
 
+	intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
+
 	DRM_DEBUG_KMS("enabling %s\n", pll->name);
 	pll->enable(dev_priv, pll);
 	pll->on = true;
@@ -1850,6 +1852,8 @@ static void intel_disable_shared_dpll(struct intel_crtc *crtc)
 	DRM_DEBUG_KMS("disabling %s\n", pll->name);
 	pll->disable(dev_priv, pll);
 	pll->on = false;
+
+	intel_display_power_put(dev_priv, POWER_DOMAIN_PLLS);
 }
 
 static void ironlake_enable_pch_transcoder(struct drm_i915_private *dev_priv,
@@ -11302,6 +11306,9 @@ static bool ibx_pch_dpll_get_hw_state(struct drm_i915_private *dev_priv,
 {
 	uint32_t val;
 
+	if (!intel_display_power_enabled(dev_priv, POWER_DOMAIN_PLLS))
+		return false;
+
 	val = I915_READ(PCH_DPLL(pll->id));
 	hw_state->dpll = val;
 	hw_state->fp0 = I915_READ(PCH_FP0(pll->id));
@@ -12867,6 +12874,9 @@ static void intel_modeset_readout_hw_state(struct drm_device *dev)
 
 		DRM_DEBUG_KMS("%s hw state readout: refcount %i, on %i\n",
 			      pll->name, pll->refcount, pll->on);
+
+		if (pll->refcount)
+			intel_display_power_get(dev_priv, POWER_DOMAIN_PLLS);
 	}
 
 	list_for_each_entry(encoder, &dev->mode_config.encoder_list,

drivers/gpu/drm/i915/intel_pm.c

@@ -6346,6 +6346,7 @@ EXPORT_SYMBOL_GPL(i915_get_cdclk_freq);
 	BIT(POWER_DOMAIN_PORT_DDI_D_2_LANES) |		\
 	BIT(POWER_DOMAIN_PORT_DDI_D_4_LANES) |		\
 	BIT(POWER_DOMAIN_PORT_CRT) |			\
+	BIT(POWER_DOMAIN_PLLS) |			\
 	BIT(POWER_DOMAIN_INIT))
 #define HSW_DISPLAY_POWER_DOMAINS (				\
 	(POWER_DOMAIN_MASK & ~HSW_ALWAYS_ON_POWER_DOMAINS) |	\