ALSA: hda: add component support

Register a component master to be used to interface with the i915
driver. This is meant to replace the current interface which is based on
module symbol lookups.

Note that currently we keep the existing behavior and pin the i915
module while the hda driver is loaded. Using the component interface
allows us to remove this dependency once support for dynamically
enabling / disabling the HDMI functionality is added to the driver.

v2:
- change roles between the hda and i915 components (Daniel)
v3:
- rename display_component to audio_component (Daniel)
v4:
- move removal of i915_powerwell.h from this patch to the next (Takashi)
- request_module fails if module support isn't enabled, so ignore
  any error it returns and depend on the following NULL check of the
  component ops (Takashi)
- change over to using dev_* instead of pr_* (Takashi)
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>

sound/pci/hda/hda_i915.c

@@ -18,8 +18,10 @@
 
 #include <linux/init.h>
 #include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/component.h>
+#include <drm/i915_component.h>
 #include <sound/core.h>
-#include <drm/i915_powerwell.h>
 #include "hda_priv.h"
 #include "hda_intel.h"
 
@@ -31,32 +33,33 @@
 #define AZX_REG_EM4			0x100c
 #define AZX_REG_EM5			0x1010
 
-static int (*get_power)(void);
-static int (*put_power)(void);
-static int (*get_cdclk)(void);
-
 int hda_display_power(struct hda_intel *hda, bool enable)
 {
-	if (!get_power || !put_power)
+	struct i915_audio_component *acomp = &hda->audio_component;
+
+	if (!acomp->ops)
 		return -ENODEV;
 
-	pr_debug("HDA display power %s \n",
-			enable ? "Enable" : "Disable");
+	dev_dbg(&hda->chip.pci->dev, "display power %s\n",
+		enable ? "enable" : "disable");
 	if (enable)
-		return get_power();
+		acomp->ops->get_power(acomp->dev);
 	else
-		return put_power();
+		acomp->ops->put_power(acomp->dev);
+
+	return 0;
 }
 
 void haswell_set_bclk(struct hda_intel *hda)
 {
 	int cdclk_freq;
 	unsigned int bclk_m, bclk_n;
+	struct i915_audio_component *acomp = &hda->audio_component;
 
-	if (!get_cdclk)
+	if (!acomp->ops)
 		return;
 
-	cdclk_freq = get_cdclk();
+	cdclk_freq = acomp->ops->get_cdclk_freq(acomp->dev);
 	switch (cdclk_freq) {
 	case 337500:
 		bclk_m = 16;
@@ -84,47 +87,104 @@ void haswell_set_bclk(struct hda_intel *hda)
 	azx_writew(&hda->chip, EM5, bclk_n);
 }
 
-
-int hda_i915_init(struct hda_intel *hda)
+static int hda_component_master_bind(struct device *dev)
 {
-	int err = 0;
+	struct snd_card *card = dev_get_drvdata(dev);
+	struct azx *chip = card->private_data;
+	struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
+	struct i915_audio_component *acomp = &hda->audio_component;
+	int ret;
+
+	ret = component_bind_all(dev, acomp);
+	if (ret < 0)
+		return ret;
+
+	if (WARN_ON(!(acomp->dev && acomp->ops && acomp->ops->get_power &&
+		      acomp->ops->put_power && acomp->ops->get_cdclk_freq))) {
+		ret = -EINVAL;
+		goto out_unbind;
+	}
 
-	get_power = symbol_request(i915_request_power_well);
-	if (!get_power) {
-		pr_warn("hda-i915: get_power symbol get fail\n");
-		return -ENODEV;
+	/*
+	 * Atm, we don't support dynamic unbinding initiated by the child
+	 * component, so pin its containing module until we unbind.
+	 */
+	if (!try_module_get(acomp->ops->owner)) {
+		ret = -ENODEV;
+		goto out_unbind;
 	}
 
-	put_power = symbol_request(i915_release_power_well);
-	if (!put_power) {
-		symbol_put(i915_request_power_well);
-		get_power = NULL;
-		return -ENODEV;
+	return 0;
+
+out_unbind:
+	component_unbind_all(dev, acomp);
+
+	return ret;
+}
+
+static void hda_component_master_unbind(struct device *dev)
+{
+	struct snd_card *card = dev_get_drvdata(dev);
+	struct azx *chip = card->private_data;
+	struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
+	struct i915_audio_component *acomp = &hda->audio_component;
+
+	module_put(acomp->ops->owner);
+	component_unbind_all(dev, acomp);
+	WARN_ON(acomp->ops || acomp->dev);
+}
+
+static const struct component_master_ops hda_component_master_ops = {
+	.bind = hda_component_master_bind,
+	.unbind = hda_component_master_unbind,
+};
+
+static int hda_component_master_match(struct device *dev, void *data)
+{
+	/* i915 is the only supported component */
+	return !strcmp(dev->driver->name, "i915");
+}
+
+int hda_i915_init(struct hda_intel *hda)
+{
+	struct component_match *match = NULL;
+	struct device *dev = &hda->chip.pci->dev;
+	struct i915_audio_component *acomp = &hda->audio_component;
+	int ret;
+
+	component_match_add(dev, &match, hda_component_master_match, hda);
+	ret = component_master_add_with_match(dev, &hda_component_master_ops,
+					      match);
+	if (ret < 0)
+		goto out_err;
+
+	/*
+	 * Atm, we don't support deferring the component binding, so make sure
+	 * i915 is loaded and that the binding successfully completes.
+	 */
+	request_module("i915");
+
+	if (!acomp->ops) {
+		ret = -ENODEV;
+		goto out_master_del;
 	}
 
-	get_cdclk = symbol_request(i915_get_cdclk_freq);
-	if (!get_cdclk)	/* may have abnormal BCLK and audio playback rate */
-		pr_warn("hda-i915: get_cdclk symbol get fail\n");
+	dev_dbg(dev, "bound to i915 component master\n");
 
-	pr_debug("HDA driver get symbol successfully from i915 module\n");
+	return 0;
+out_master_del:
+	component_master_del(dev, &hda_component_master_ops);
+out_err:
+	dev_err(dev, "failed to add i915 component master (%d)\n", ret);
 
-	return err;
+	return ret;
 }
 
 int hda_i915_exit(struct hda_intel *hda)
 {
-	if (get_power) {
-		symbol_put(i915_request_power_well);
-		get_power = NULL;
-	}
-	if (put_power) {
-		symbol_put(i915_release_power_well);
-		put_power = NULL;
-	}
-	if (get_cdclk) {
-		symbol_put(i915_get_cdclk_freq);
-		get_cdclk = NULL;
-	}
+	struct device *dev = &hda->chip.pci->dev;
+
+	component_master_del(dev, &hda_component_master_ops);
 
 	return 0;
 }

sound/pci/hda/hda_intel.c

@@ -1890,11 +1890,8 @@ static int azx_probe_continue(struct azx *chip)
 	if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
 #ifdef CONFIG_SND_HDA_I915
 		err = hda_i915_init(hda);
-		if (err < 0) {
-			dev_err(chip->card->dev,
-				"Error request power-well from i915\n");
+		if (err < 0)
 			goto out_free;
-		}
 		err = hda_display_power(hda, true);
 		if (err < 0) {
 			dev_err(chip->card->dev,

sound/pci/hda/hda_intel.h

@@ -16,6 +16,7 @@
 #ifndef __SOUND_HDA_INTEL_H
 #define __SOUND_HDA_INTEL_H
 
+#include <drm/i915_component.h>
 #include "hda_priv.h"
 
 struct hda_intel {
@@ -41,6 +42,9 @@ struct hda_intel {
 
 	/* secondary power domain for hdmi audio under vga device */
 	struct dev_pm_domain hdmi_pm_domain;
+
+	/* i915 component interface */
+	struct i915_audio_component audio_component;
 };
 
 #ifdef CONFIG_SND_HDA_I915