1 files changed, 260 insertions, 0 deletions
diff --git a/sound/core/device.c b/sound/core/device.c
new file mode 100644
index 000000000..bf0b04a7e
--- /dev/null
+++ b/sound/core/device.c
@@ -0,0 +1,260 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *  Device management routines
+ *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
+ */
+
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/export.h>
+#include <linux/errno.h>
+#include <sound/core.h>
+
+/**
+ * snd_device_new - create an ALSA device component
+ * @card: the card instance
+ * @type: the device type, SNDRV_DEV_XXX
+ * @device_data: the data pointer of this device
+ * @ops: the operator table
+ *
+ * Creates a new device component for the given data pointer.
+ * The device will be assigned to the card and managed together
+ * by the card.
+ *
+ * The data pointer plays a role as the identifier, too, so the
+ * pointer address must be unique and unchanged.
+ *
+ * Return: Zero if successful, or a negative error code on failure.
+ */
+int snd_device_new(struct snd_card *card, enum snd_device_type type,
+		   void *device_data, const struct snd_device_ops *ops)
+{
+	struct snd_device *dev;
+	struct list_head *p;
+
+	if (snd_BUG_ON(!card || !device_data || !ops))
+		return -ENXIO;
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+	INIT_LIST_HEAD(&dev->list);
+	dev->card = card;
+	dev->type = type;
+	dev->state = SNDRV_DEV_BUILD;
+	dev->device_data = device_data;
+	dev->ops = ops;
+
+	/* insert the entry in an incrementally sorted list */
+	list_for_each_prev(p, &card->devices) {
+		struct snd_device *pdev = list_entry(p, struct snd_device, list);
+		if ((unsigned int)pdev->type <= (unsigned int)type)
+			break;
+	}
+
+	list_add(&dev->list, p);
+	return 0;
+}
+EXPORT_SYMBOL(snd_device_new);
+
+static void __snd_device_disconnect(struct snd_device *dev)
+{
+	if (dev->state == SNDRV_DEV_REGISTERED) {
+		if (dev->ops->dev_disconnect &&
+		    dev->ops->dev_disconnect(dev))
+			dev_err(dev->card->dev, "device disconnect failure\n");
+		dev->state = SNDRV_DEV_DISCONNECTED;
+	}
+}
+
+static void __snd_device_free(struct snd_device *dev)
+{
+	/* unlink */
+	list_del(&dev->list);
+
+	__snd_device_disconnect(dev);
+	if (dev->ops->dev_free) {
+		if (dev->ops->dev_free(dev))
+			dev_err(dev->card->dev, "device free failure\n");
+	}
+	kfree(dev);
+}
+
+static struct snd_device *look_for_dev(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+
+	list_for_each_entry(dev, &card->devices, list)
+		if (dev->device_data == device_data)
+			return dev;
+
+	return NULL;
+}
+
+/**
+ * snd_device_disconnect - disconnect the device
+ * @card: the card instance
+ * @device_data: the data pointer to disconnect
+ *
+ * Turns the device into the disconnection state, invoking
+ * dev_disconnect callback, if the device was already registered.
+ *
+ * Usually called from snd_card_disconnect().
+ *
+ * Return: Zero if successful, or a negative error code on failure or if the
+ * device not found.
+ */
+void snd_device_disconnect(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+
+	if (snd_BUG_ON(!card || !device_data))
+		return;
+	dev = look_for_dev(card, device_data);
+	if (dev)
+		__snd_device_disconnect(dev);
+	else
+		dev_dbg(card->dev, "device disconnect %p (from %pS), not found\n",
+			device_data, __builtin_return_address(0));
+}
+EXPORT_SYMBOL_GPL(snd_device_disconnect);
+
+/**
+ * snd_device_free - release the device from the card
+ * @card: the card instance
+ * @device_data: the data pointer to release
+ *
+ * Removes the device from the list on the card and invokes the
+ * callbacks, dev_disconnect and dev_free, corresponding to the state.
+ * Then release the device.
+ */
+void snd_device_free(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+	
+	if (snd_BUG_ON(!card || !device_data))
+		return;
+	dev = look_for_dev(card, device_data);
+	if (dev)
+		__snd_device_free(dev);
+	else
+		dev_dbg(card->dev, "device free %p (from %pS), not found\n",
+			device_data, __builtin_return_address(0));
+}
+EXPORT_SYMBOL(snd_device_free);
+
+static int __snd_device_register(struct snd_device *dev)
+{
+	if (dev->state == SNDRV_DEV_BUILD) {
+		if (dev->ops->dev_register) {
+			int err = dev->ops->dev_register(dev);
+			if (err < 0)
+				return err;
+		}
+		dev->state = SNDRV_DEV_REGISTERED;
+	}
+	return 0;
+}
+
+/**
+ * snd_device_register - register the device
+ * @card: the card instance
+ * @device_data: the data pointer to register
+ *
+ * Registers the device which was already created via
+ * snd_device_new().  Usually this is called from snd_card_register(),
+ * but it can be called later if any new devices are created after
+ * invocation of snd_card_register().
+ *
+ * Return: Zero if successful, or a negative error code on failure or if the
+ * device not found.
+ */
+int snd_device_register(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+
+	if (snd_BUG_ON(!card || !device_data))
+		return -ENXIO;
+	dev = look_for_dev(card, device_data);
+	if (dev)
+		return __snd_device_register(dev);
+	snd_BUG();
+	return -ENXIO;
+}
+EXPORT_SYMBOL(snd_device_register);
+
+/*
+ * register all the devices on the card.
+ * called from init.c
+ */
+int snd_device_register_all(struct snd_card *card)
+{
+	struct snd_device *dev;
+	int err;
+	
+	if (snd_BUG_ON(!card))
+		return -ENXIO;
+	list_for_each_entry(dev, &card->devices, list) {
+		err = __snd_device_register(dev);
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+/*
+ * disconnect all the devices on the card.
+ * called from init.c
+ */
+void snd_device_disconnect_all(struct snd_card *card)
+{
+	struct snd_device *dev;
+
+	if (snd_BUG_ON(!card))
+		return;
+	list_for_each_entry_reverse(dev, &card->devices, list)
+		__snd_device_disconnect(dev);
+}
+
+/*
+ * release all the devices on the card.
+ * called from init.c
+ */
+void snd_device_free_all(struct snd_card *card)
+{
+	struct snd_device *dev, *next;
+
+	if (snd_BUG_ON(!card))
+		return;
+	list_for_each_entry_safe_reverse(dev, next, &card->devices, list) {
+		/* exception: free ctl and lowlevel stuff later */
+		if (dev->type == SNDRV_DEV_CONTROL ||
+		    dev->type == SNDRV_DEV_LOWLEVEL)
+			continue;
+		__snd_device_free(dev);
+	}
+
+	/* free all */
+	list_for_each_entry_safe_reverse(dev, next, &card->devices, list)
+		__snd_device_free(dev);
+}
+
+/**
+ * snd_device_get_state - Get the current state of the given device
+ * @card: the card instance
+ * @device_data: the data pointer to release
+ *
+ * Returns the current state of the given device object.  For the valid
+ * device, either @SNDRV_DEV_BUILD, @SNDRV_DEV_REGISTERED or
+ * @SNDRV_DEV_DISCONNECTED is returned.
+ * Or for a non-existing device, -1 is returned as an error.
+ */
+int snd_device_get_state(struct snd_card *card, void *device_data)
+{
+	struct snd_device *dev;
+
+	dev = look_for_dev(card, device_data);
+	if (dev)
+		return dev->state;
+	return -1;
+}
+EXPORT_SYMBOL_GPL(snd_device_get_state);