[Intel-gfx] [PATCH 5/5] drm/i915/eDP: Move pps_lock() and edp_panel_vdd_on() to top

[Egbert Eich]

On eDP each low level transfer is wrapped by pps_lock()/unlock()
and edp_panel_vdd_on()/off(). Since PPS locking can be quite expensive
and each call to master_xfer() or dpcd_access() may call these low level
transfer functions many times it may introduce a considerable delay.
Move locking/VDD enablement to the top so that it is performed only
once per master_xfer() or dpcd_access().
This fixes https://bugs.freedesktop.org/show_bug.cgi?id=86201

Signed-off-by: Egbert Eich <eich at suse.de>
---
 drivers/gpu/drm/i915/intel_dp.c  | 116 ++++++++++++++++++++++++++++++++-------
 drivers/gpu/drm/i915/intel_drv.h |   5 ++
 2 files changed, 100 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a24c8cc7..164f80e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -807,19 +807,6 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
 	uint32_t status;
 	int try, clock = 0;
 	bool has_aux_irq = HAS_AUX_IRQ(dev);
-	bool vdd = false;
-
-	if (is_edp(intel_dp)) {
-		pps_lock(intel_dp);
-
-		/*
-		 * We will be called with VDD already enabled for dpcd/edid/oui reads.
-		 * In such cases we want to leave VDD enabled and it's up to upper layers
-		 * to turn it off. But for eg. i2c-dev access we need to turn it on/off
-		 * ourselves.
-		 */
-		vdd = edp_panel_vdd_on(intel_dp);
-	}
 
 	/* dp aux is extremely sensitive to irq latency, hence request the
 	 * lowest possible wakeup latency and so prevent the cpu from going into
@@ -926,13 +913,6 @@ out:
 	pm_qos_update_request(&dev_priv->pm_qos, PM_QOS_DEFAULT_VALUE);
 	intel_aux_display_runtime_put(dev_priv);
 
-	if (is_edp(intel_dp)) {
-		if (vdd)
-			edp_panel_vdd_off(intel_dp, false);
-
-		pps_unlock(intel_dp);
-	}
-
 	return ret;
 }
 
@@ -1001,6 +981,97 @@ intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 	return ret;
 }
 
+int intel_edp_dpcd_access(struct drm_dp_aux *aux, u8 request,
+			      unsigned int offset, void *buffer, size_t size)
+{
+	struct intel_dp *intel_dp = container_of(aux, struct intel_dp, aux);
+	bool vdd = false;
+	int ret;
+
+	pps_lock(intel_dp);
+	/*
+	 * We will be called with VDD already enabled for dpcd/edid/oui reads.
+	 * In such cases we want to leave VDD enabled and it's up to upper
+	 * layers to turn it off. But for eg. i2c-dev access we need to turn
+	 * it on/off ourselves.
+	 */
+	vdd = edp_panel_vdd_on(intel_dp);
+
+	ret = drm_dp_dpcd_access(aux, request, offset, buffer, size);
+
+	if (vdd)
+		edp_panel_vdd_off(intel_dp, false);
+
+	pps_unlock(intel_dp);
+
+	return ret;
+}
+
+static int
+intel_edp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs,
+			  int num)
+{
+	struct drm_dp_aux *aux = adapter->algo_data;
+	struct intel_dp *intel_dp = container_of(aux, struct intel_dp, aux);
+	bool vdd = false;
+	int ret;
+
+	pps_lock(intel_dp);
+	/*
+	 * We will be called with VDD already enabled for dpcd/edid/oui reads.
+	 * In such cases we want to leave VDD enabled and it's up to upper
+	 * layers to turn it off. But for eg. i2c-dev access we need to turn
+	 * it on/off ourselves.
+	 */
+	vdd = edp_panel_vdd_on(intel_dp);
+
+	ret = drm_dp_i2c_xfer(adapter, msgs, num);
+
+	if (vdd)
+		edp_panel_vdd_off(intel_dp, false);
+
+	pps_unlock(intel_dp);
+
+	return ret;
+}
+
+static u32 intel_edp_i2c_functionality(struct i2c_adapter *adapter)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |
+	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |
+	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |
+	       I2C_FUNC_10BIT_ADDR;
+}
+
+static const struct i2c_algorithm intel_edp_i2c_algo = {
+	.functionality = intel_edp_i2c_functionality,
+	.master_xfer = intel_edp_i2c_xfer,
+};
+
+/*
+ * intel_edp_aux_register() - Intel replacement for
+ *                           drm_dp_aux_register().
+ */
+static int intel_edp_aux_register(struct drm_dp_aux *aux)
+{
+	mutex_init(&aux->hw_mutex);
+	aux->dpcd_access = intel_edp_dpcd_access;
+
+	aux->ddc.algo = &intel_edp_i2c_algo;
+	aux->ddc.algo_data = aux;
+	aux->ddc.retries = 3;
+
+	aux->ddc.class = I2C_CLASS_DDC;
+	aux->ddc.owner = THIS_MODULE;
+	aux->ddc.dev.parent = aux->dev;
+	aux->ddc.dev.of_node = aux->dev->of_node;
+
+	strlcpy(aux->ddc.name, aux->name ? aux->name : dev_name(aux->dev),
+		sizeof(aux->ddc.name));
+
+	return i2c_add_adapter(&aux->ddc);
+}
+
 static void
 intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
 {
@@ -1050,7 +1121,10 @@ intel_dp_aux_init(struct intel_dp *intel_dp, struct intel_connector *connector)
 	DRM_DEBUG_KMS("registering %s bus for %s\n", name,
 		      connector->base.kdev->kobj.name);
 
-	ret = drm_dp_aux_register(&intel_dp->aux);
+	if (!is_edp(intel_dp))
+		ret = drm_dp_aux_register(&intel_dp->aux);
+	else
+		ret = intel_edp_aux_register(&intel_dp->aux);
 	if (ret < 0) {
 		DRM_ERROR("drm_dp_aux_register() for %s failed (%d)\n",
 			  name, ret);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 44b153c5..783261a 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -589,6 +589,11 @@ struct intel_dp {
 	uint8_t psr_dpcd[EDP_PSR_RECEIVER_CAP_SIZE];
 	uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
 	struct drm_dp_aux aux;
+	struct i2c_algorithm ddc_algo;
+	int (*aux_master_xfer)(struct i2c_adapter *adap, struct i2c_msg *msgs,
+			   int num);
+	int (*dpcd_access)(struct drm_dp_aux *aux, u8 request,
+			   unsigned int offset, void *buffer, size_t size);
 	uint8_t train_set[4];
 	int panel_power_up_delay;
 	int panel_power_down_delay;
-- 
1.8.4.5