drm/i915: add component support

Register a component to be used to interface with the snd_hda_intel
driver. This is meant to replace the same interface that is currently
based on module symbol lookup.

v2:
- change roles between the hda and i915 components (Daniel)
- add the implementation to a new file (Jani)
- use better namespacing (Jani)
v3:
- move the implementation to intel_audio.c (Daniel)
- rename display_component to audio_component (Daniel)
- add kerneldoc (Daniel)
v4:
- run forgotten git rm i915_component.c (Jani)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

4 files changed, 119 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index ecee3bcc8772..26b3199e0af2 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -830,6 +830,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 
         intel_runtime_pm_enable(dev_priv);
 
+        i915_audio_component_init(dev_priv);
+
         return 0;
 
 out_power_well:
@@ -870,6 +872,8 @@ int i915_driver_unload(struct drm_device *dev)
         struct drm_i915_private *dev_priv = dev->dev_private;
         int ret;
 
+        i915_audio_component_cleanup(dev_priv);
+
         ret = i915_gem_suspend(dev);
         if (ret) {
                 DRM_ERROR("failed to idle hardware: %d\n", ret);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index a343f2f35dfd..176afc507f7c 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -1698,6 +1698,9 @@ struct drm_i915_private {
         struct drm_property *broadcast_rgb_property;
         struct drm_property *force_audio_property;
 
+        /* hda/i915 audio component */
+        bool audio_component_registered;
+
         uint32_t hw_context_size;
         struct list_head context_list;
 
diff --git a/drivers/gpu/drm/i915/intel_audio.c b/drivers/gpu/drm/i915/intel_audio.c
index 2c7ed5cb29c0..ee41b882e71a 100644
--- a/drivers/gpu/drm/i915/intel_audio.c
+++ b/drivers/gpu/drm/i915/intel_audio.c
@@ -22,6 +22,9 @@
  */
 
 #include <linux/kernel.h>
+#include <linux/component.h>
+#include <drm/i915_component.h>
+#include "intel_drv.h"
 
 #include <drm/drmP.h>
 #include <drm/drm_edid.h>
@@ -461,3 +464,110 @@ void intel_init_audio(struct drm_device *dev)
                 dev_priv->display.audio_codec_disable = ilk_audio_codec_disable;
         }
 }
+
+static void i915_audio_component_get_power(struct device *dev)
+{
+        intel_display_power_get(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
+}
+
+static void i915_audio_component_put_power(struct device *dev)
+{
+        intel_display_power_put(dev_to_i915(dev), POWER_DOMAIN_AUDIO);
+}
+
+/* Get CDCLK in kHz  */
+static int i915_audio_component_get_cdclk_freq(struct device *dev)
+{
+        struct drm_i915_private *dev_priv = dev_to_i915(dev);
+        int ret;
+
+        if (WARN_ON_ONCE(!HAS_DDI(dev_priv)))
+                return -ENODEV;
+
+        intel_display_power_get(dev_priv, POWER_DOMAIN_AUDIO);
+        ret = intel_ddi_get_cdclk_freq(dev_priv);
+        intel_display_power_put(dev_priv, POWER_DOMAIN_AUDIO);
+
+        return ret;
+}
+
+static const struct i915_audio_component_ops i915_audio_component_ops = {
+        .owner          = THIS_MODULE,
+        .get_power      = i915_audio_component_get_power,
+        .put_power      = i915_audio_component_put_power,
+        .get_cdclk_freq = i915_audio_component_get_cdclk_freq,
+};
+
+static int i915_audio_component_bind(struct device *i915_dev,
+                                     struct device *hda_dev, void *data)
+{
+        struct i915_audio_component *acomp = data;
+
+        if (WARN_ON(acomp->ops || acomp->dev))
+                return -EEXIST;
+
+        acomp->ops = &i915_audio_component_ops;
+        acomp->dev = i915_dev;
+
+        return 0;
+}
+
+static void i915_audio_component_unbind(struct device *i915_dev,
+                                        struct device *hda_dev, void *data)
+{
+        struct i915_audio_component *acomp = data;
+
+        acomp->ops = NULL;
+        acomp->dev = NULL;
+}
+
+static const struct component_ops i915_audio_component_bind_ops = {
+        .bind   = i915_audio_component_bind,
+        .unbind = i915_audio_component_unbind,
+};
+
+/**
+ * i915_audio_component_init - initialize and register the audio component
+ * @dev_priv: i915 device instance
+ *
+ * This will register with the component framework a child component which
+ * will bind dynamically to the snd_hda_intel driver's corresponding master
+ * component when the latter is registered. During binding the child
+ * initializes an instance of struct i915_audio_component which it receives
+ * from the master. The master can then start to use the interface defined by
+ * this struct. Each side can break the binding at any point by deregistering
+ * its own component after which each side's component unbind callback is
+ * called.
+ *
+ * We ignore any error during registration and continue with reduced
+ * functionality (i.e. without HDMI audio).
+ */
+void i915_audio_component_init(struct drm_i915_private *dev_priv)
+{
+        int ret;
+
+        ret = component_add(dev_priv->dev->dev, &i915_audio_component_bind_ops);
+        if (ret < 0) {
+                DRM_ERROR("failed to add audio component (%d)\n", ret);
+                /* continue with reduced functionality */
+                return;
+        }
+
+        dev_priv->audio_component_registered = true;
+}
+
+/**
+ * i915_audio_component_cleanup - deregister the audio component
+ * @dev_priv: i915 device instance
+ *
+ * Deregisters the audio component, breaking any existing binding to the
+ * corresponding snd_hda_intel driver's master component.
+ */
+void i915_audio_component_cleanup(struct drm_i915_private *dev_priv)
+{
+        if (!dev_priv->audio_component_registered)
+                return;
+
+        component_del(dev_priv->dev->dev, &i915_audio_component_bind_ops);
+        dev_priv->audio_component_registered = false;
+}
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 25fdbb16d4e0..e88fd5d12f05 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -872,6 +872,8 @@ void intel_fb_obj_flush(struct drm_i915_gem_object *obj, bool retire);
 void intel_init_audio(struct drm_device *dev);
 void intel_audio_codec_enable(struct intel_encoder *encoder);
 void intel_audio_codec_disable(struct intel_encoder *encoder);
+void i915_audio_component_init(struct drm_i915_private *dev_priv);
+void i915_audio_component_cleanup(struct drm_i915_private *dev_priv);
 
 /* intel_display.c */
 const char *intel_output_name(int output);