ALSA: hda - Bind codecs via standard bus

Now we create the standard HD-audio bus (/sys/bus/hdaudio), and bind
the codec driver with the codec device over there.  This is the first
step of the whole transition so that the changes to each codec driver
are kept as minimal as possible.

Each codec driver needs to register hda_codec_driver struct containing
the currently existing preset via the new helper macro
module_hda_codec_driver().  The old hda_codec_preset_list is replaced
with this infrastructure.  The generic parsers (for HDMI and other)
are also included in the preset with the special IDs to bind
uniquely.

In HD-audio core side, the device binding code is split to
hda_bind.c.  It provides the snd_hda_bus_type implementation to match
the codec driver with the given codec vendor ID.  It also manages the
module auto-loading by itself like before: when the matching isn't
found, it tries to probe the corresponding codec modules, and finally
falls back to the generic drivers.  (The special ID mentioned above is
set at this stage.)

The only visible change to outside is that the hdaudio sysfs entry now
appears in /sys/bus/devices, not as a sound class device.

More works to move the suspend/resume and remove ops will be
(hopefully) done in later patches.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/Makefile

@@ -4,7 +4,7 @@ snd-hda-tegra-objs := hda_tegra.o
 # for haswell power well
 snd-hda-intel-$(CONFIG_SND_HDA_I915) +=	hda_i915.o
 
-snd-hda-codec-y := hda_codec.o hda_jack.o hda_auto_parser.o hda_sysfs.o
+snd-hda-codec-y := hda_bind.o hda_codec.o hda_jack.o hda_auto_parser.o hda_sysfs.o
 snd-hda-codec-$(CONFIG_PROC_FS) += hda_proc.o
 snd-hda-codec-$(CONFIG_SND_HDA_HWDEP) += hda_hwdep.o
 snd-hda-codec-$(CONFIG_SND_HDA_INPUT_BEEP) += hda_beep.o

sound/pci/hda/hda_bind.c

@@ -0,0 +1,320 @@
+/*
+ * HD-audio codec driver binding
+ * Copyright (c) Takashi Iwai <tiwai@suse.de>
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/export.h>
+#include <sound/core.h>
+#include "hda_codec.h"
+#include "hda_local.h"
+
+/* codec vendor labels */
+struct hda_vendor_id {
+	unsigned int id;
+	const char *name;
+};
+
+static struct hda_vendor_id hda_vendor_ids[] = {
+	{ 0x1002, "ATI" },
+	{ 0x1013, "Cirrus Logic" },
+	{ 0x1057, "Motorola" },
+	{ 0x1095, "Silicon Image" },
+	{ 0x10de, "Nvidia" },
+	{ 0x10ec, "Realtek" },
+	{ 0x1102, "Creative" },
+	{ 0x1106, "VIA" },
+	{ 0x111d, "IDT" },
+	{ 0x11c1, "LSI" },
+	{ 0x11d4, "Analog Devices" },
+	{ 0x13f6, "C-Media" },
+	{ 0x14f1, "Conexant" },
+	{ 0x17e8, "Chrontel" },
+	{ 0x1854, "LG" },
+	{ 0x1aec, "Wolfson Microelectronics" },
+	{ 0x1af4, "QEMU" },
+	{ 0x434d, "C-Media" },
+	{ 0x8086, "Intel" },
+	{ 0x8384, "SigmaTel" },
+	{} /* terminator */
+};
+
+/*
+ * find a matching codec preset
+ */
+static int hda_bus_match(struct device *dev, struct device_driver *drv)
+{
+	struct hda_codec *codec = container_of(dev, struct hda_codec, dev);
+	struct hda_codec_driver *driver =
+		container_of(drv, struct hda_codec_driver, driver);
+	const struct hda_codec_preset *preset;
+	/* check probe_id instead of vendor_id if set */
+	u32 id = codec->probe_id ? codec->probe_id : codec->vendor_id;
+
+	for (preset = driver->preset; preset->id; preset++) {
+		u32 mask = preset->mask;
+
+		if (preset->afg && preset->afg != codec->afg)
+			continue;
+		if (preset->mfg && preset->mfg != codec->mfg)
+			continue;
+		if (!mask)
+			mask = ~0;
+		if (preset->id == (id & mask) &&
+		    (!preset->rev || preset->rev == codec->revision_id)) {
+			codec->preset = preset;
+			return 1;
+		}
+	}
+	return 0;
+}
+
+/* reset the codec name from the preset */
+static int codec_refresh_name(struct hda_codec *codec, const char *name)
+{
+	char tmp[16];
+
+	kfree(codec->chip_name);
+	if (!name) {
+		sprintf(tmp, "ID %x", codec->vendor_id & 0xffff);
+		name = tmp;
+	}
+	codec->chip_name = kstrdup(name, GFP_KERNEL);
+	return codec->chip_name ? 0 : -ENOMEM;
+}
+
+static int hda_codec_driver_probe(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+	struct module *owner = dev->driver->owner;
+	int err;
+
+	if (WARN_ON(!codec->preset))
+		return -EINVAL;
+
+	err = codec_refresh_name(codec, codec->preset->name);
+	if (err < 0)
+		goto error;
+
+	if (!try_module_get(owner)) {
+		err = -EINVAL;
+		goto error;
+	}
+
+	err = codec->preset->patch(codec);
+	if (err < 0) {
+		module_put(owner);
+		goto error;
+	}
+
+	return 0;
+
+ error:
+	codec->preset = NULL;
+	memset(&codec->patch_ops, 0, sizeof(codec->patch_ops));
+	return err;
+}
+
+static int hda_codec_driver_remove(struct device *dev)
+{
+	struct hda_codec *codec = dev_to_hda_codec(dev);
+
+	if (codec->patch_ops.free)
+		codec->patch_ops.free(codec);
+	codec->preset = NULL;
+	memset(&codec->patch_ops, 0, sizeof(codec->patch_ops));
+	module_put(dev->driver->owner);
+	return 0;
+}
+
+int __hda_codec_driver_register(struct hda_codec_driver *drv, const char *name,
+			       struct module *owner)
+{
+	drv->driver.name = name;
+	drv->driver.owner = owner;
+	drv->driver.bus = &snd_hda_bus_type;
+	drv->driver.probe = hda_codec_driver_probe;
+	drv->driver.remove = hda_codec_driver_remove;
+	/* TODO: PM and others */
+	return driver_register(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(__hda_codec_driver_register);
+
+void hda_codec_driver_unregister(struct hda_codec_driver *drv)
+{
+	driver_unregister(&drv->driver);
+}
+EXPORT_SYMBOL_GPL(hda_codec_driver_unregister);
+
+static inline bool codec_probed(struct hda_codec *codec)
+{
+	return device_attach(hda_codec_dev(codec)) > 0 && codec->preset;
+}
+
+/* try to auto-load and bind the codec module */
+static void codec_bind_module(struct hda_codec *codec)
+{
+#ifdef MODULE
+	request_module("snd-hda-codec-id:%08x", codec->vendor_id);
+	if (codec_probed(codec))
+		return;
+	request_module("snd-hda-codec-id:%04x*",
+		       (codec->vendor_id >> 16) & 0xffff);
+	if (codec_probed(codec))
+		return;
+#endif
+}
+
+/* store the codec vendor name */
+static int get_codec_vendor_name(struct hda_codec *codec)
+{
+	const struct hda_vendor_id *c;
+	const char *vendor = NULL;
+	u16 vendor_id = codec->vendor_id >> 16;
+	char tmp[16];
+
+	for (c = hda_vendor_ids; c->id; c++) {
+		if (c->id == vendor_id) {
+			vendor = c->name;
+			break;
+		}
+	}
+	if (!vendor) {
+		sprintf(tmp, "Generic %04x", vendor_id);
+		vendor = tmp;
+	}
+	codec->vendor_name = kstrdup(vendor, GFP_KERNEL);
+	if (!codec->vendor_name)
+		return -ENOMEM;
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_CODEC_HDMI)
+/* if all audio out widgets are digital, let's assume the codec as a HDMI/DP */
+static bool is_likely_hdmi_codec(struct hda_codec *codec)
+{
+	hda_nid_t nid = codec->start_nid;
+	int i;
+
+	for (i = 0; i < codec->num_nodes; i++, nid++) {
+		unsigned int wcaps = get_wcaps(codec, nid);
+		switch (get_wcaps_type(wcaps)) {
+		case AC_WID_AUD_IN:
+			return false; /* HDMI parser supports only HDMI out */
+		case AC_WID_AUD_OUT:
+			if (!(wcaps & AC_WCAP_DIGITAL))
+				return false;
+			break;
+		}
+	}
+	return true;
+}
+#else
+/* no HDMI codec parser support */
+#define is_likely_hdmi_codec(codec)	false
+#endif /* CONFIG_SND_HDA_CODEC_HDMI */
+
+static int codec_bind_generic(struct hda_codec *codec)
+{
+	if (codec->probe_id)
+		return -ENODEV;
+
+	if (is_likely_hdmi_codec(codec)) {
+		codec->probe_id = HDA_CODEC_ID_GENERIC_HDMI;
+#if IS_MODULE(CONFIG_SND_HDA_CODEC_HDMI)
+		request_module("snd-hda-codec-hdmi");
+#endif
+		if (codec_probed(codec))
+			return 0;
+	}
+
+	codec->probe_id = HDA_CODEC_ID_GENERIC;
+#if IS_MODULE(CONFIG_SND_HDA_GENERIC)
+	request_module("snd-hda-codec-generic");
+#endif
+	if (codec_probed(codec))
+		return 0;
+	return -ENODEV;
+}
+
+#if IS_ENABLED(CONFIG_SND_HDA_GENERIC)
+#define is_generic_config(codec) \
+	(codec->modelname && !strcmp(codec->modelname, "generic"))
+#else
+#define is_generic_config(codec)	0
+#endif
+
+/**
+ * snd_hda_codec_configure - (Re-)configure the HD-audio codec
+ * @codec: the HDA codec
+ *
+ * Start parsing of the given codec tree and (re-)initialize the whole
+ * patch instance.
+ *
+ * Returns 0 if successful or a negative error code.
+ */
+int snd_hda_codec_configure(struct hda_codec *codec)
+{
+	int err;
+
+	if (!codec->vendor_name) {
+		err = get_codec_vendor_name(codec);
+		if (err < 0)
+			return err;
+	}
+
+	if (is_generic_config(codec))
+		codec->probe_id = HDA_CODEC_ID_GENERIC;
+	else
+		codec->probe_id = 0;
+
+	err = device_add(hda_codec_dev(codec));
+	if (err < 0)
+		return err;
+
+	if (!codec->preset)
+		codec_bind_module(codec);
+	if (!codec->preset) {
+		err = codec_bind_generic(codec);
+		if (err < 0) {
+			codec_err(codec, "Unable to bind the codec\n");
+			goto error;
+		}
+	}
+
+	/* audio codec should override the mixer name */
+	if (codec->afg || !*codec->bus->card->mixername)
+		snprintf(codec->bus->card->mixername,
+			 sizeof(codec->bus->card->mixername),
+			 "%s %s", codec->vendor_name, codec->chip_name);
+	return 0;
+
+ error:
+	device_del(hda_codec_dev(codec));
+	return err;
+}
+EXPORT_SYMBOL_GPL(snd_hda_codec_configure);
+
+/*
+ * bus registration
+ */
+struct bus_type snd_hda_bus_type = {
+	.name = "hdaudio",
+	.match = hda_bus_match,
+};
+
+static int __init hda_codec_init(void)
+{
+	return bus_register(&snd_hda_bus_type);
+}
+
+static void __exit hda_codec_exit(void)
+{
+	bus_unregister(&snd_hda_bus_type);
+}
+
+module_init(hda_codec_init);
+module_exit(hda_codec_exit);