1 files changed, 322 insertions, 0 deletions
diff --git a/sound/soc/soc-usb.c b/sound/soc/soc-usb.c
new file mode 100644
index 000000000000..26baa66d29a8
--- /dev/null
+++ b/sound/soc/soc-usb.c
@@ -0,0 +1,322 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022-2025 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+#include <linux/of.h>
+#include <linux/usb.h>
+
+#include <sound/jack.h>
+#include <sound/soc-usb.h>
+
+#include "../usb/card.h"
+
+static DEFINE_MUTEX(ctx_mutex);
+static LIST_HEAD(usb_ctx_list);
+
+static struct device_node *snd_soc_find_phandle(struct device *dev)
+{
+	struct device_node *node;
+
+	node = of_parse_phandle(dev->of_node, "usb-soc-be", 0);
+	if (!node)
+		return ERR_PTR(-ENODEV);
+
+	return node;
+}
+
+static struct snd_soc_usb *snd_soc_usb_ctx_lookup(struct device_node *node)
+{
+	struct snd_soc_usb *ctx;
+
+	if (!node)
+		return NULL;
+
+	list_for_each_entry(ctx, &usb_ctx_list, list) {
+		if (ctx->component->dev->of_node == node)
+			return ctx;
+	}
+
+	return NULL;
+}
+
+static struct snd_soc_usb *snd_soc_find_usb_ctx(struct device *dev)
+{
+	struct snd_soc_usb *ctx;
+	struct device_node *node;
+
+	node = snd_soc_find_phandle(dev);
+	if (!IS_ERR(node)) {
+		ctx = snd_soc_usb_ctx_lookup(node);
+		of_node_put(node);
+	} else {
+		ctx = snd_soc_usb_ctx_lookup(dev->of_node);
+	}
+
+	return ctx ? ctx : NULL;
+}
+
+/* SOC USB sound kcontrols */
+/**
+ * snd_soc_usb_setup_offload_jack() - Create USB offloading jack
+ * @component: USB DPCM backend DAI component
+ * @jack: jack structure to create
+ *
+ * Creates a jack device for notifying userspace of the availability
+ * of an offload capable device.
+ *
+ * Returns 0 on success, negative on error.
+ *
+ */
+int snd_soc_usb_setup_offload_jack(struct snd_soc_component *component,
+				   struct snd_soc_jack *jack)
+{
+	int ret;
+
+	ret = snd_soc_card_jack_new(component->card, "USB Offload Jack",
+				    SND_JACK_USB, jack);
+	if (ret < 0) {
+		dev_err(component->card->dev, "Unable to add USB offload jack: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = snd_soc_component_set_jack(component, jack, NULL);
+	if (ret) {
+		dev_err(component->card->dev, "Failed to set jack: %d\n", ret);
+		return ret;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_setup_offload_jack);
+
+/**
+ * snd_soc_usb_update_offload_route - Find active USB offload path
+ * @dev: USB device to get offload status
+ * @card: USB card index
+ * @pcm: USB PCM device index
+ * @direction: playback or capture direction
+ * @path: pcm or card index
+ * @route: pointer to route output array
+ *
+ * Fetch the current status for the USB SND card and PCM device indexes
+ * specified.  The "route" argument should be an array of integers being
+ * used for a kcontrol output.  The first element should have the selected
+ * card index, and the second element should have the selected pcm device
+ * index.
+ */
+int snd_soc_usb_update_offload_route(struct device *dev, int card, int pcm,
+				     int direction, enum snd_soc_usb_kctl path,
+				     long *route)
+{
+	struct snd_soc_usb *ctx;
+	int ret = -ENODEV;
+
+	mutex_lock(&ctx_mutex);
+	ctx = snd_soc_find_usb_ctx(dev);
+	if (!ctx)
+		goto exit;
+
+	if (ctx->update_offload_route_info)
+		ret = ctx->update_offload_route_info(ctx->component, card, pcm,
+						     direction, path, route);
+exit:
+	mutex_unlock(&ctx_mutex);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_update_offload_route);
+
+/**
+ * snd_soc_usb_find_priv_data() - Retrieve private data stored
+ * @usbdev: device reference
+ *
+ * Fetch the private data stored in the USB SND SoC structure.
+ *
+ */
+void *snd_soc_usb_find_priv_data(struct device *usbdev)
+{
+	struct snd_soc_usb *ctx;
+
+	mutex_lock(&ctx_mutex);
+	ctx = snd_soc_find_usb_ctx(usbdev);
+	mutex_unlock(&ctx_mutex);
+
+	return ctx ? ctx->priv_data : NULL;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_find_priv_data);
+
+/**
+ * snd_soc_usb_find_supported_format() - Check if audio format is supported
+ * @card_idx: USB sound chip array index
+ * @params: PCM parameters
+ * @direction: capture or playback
+ *
+ * Ensure that a requested audio profile from the ASoC side is able to be
+ * supported by the USB device.
+ *
+ * Return 0 on success, negative on error.
+ *
+ */
+int snd_soc_usb_find_supported_format(int card_idx,
+				      struct snd_pcm_hw_params *params,
+				      int direction)
+{
+	struct snd_usb_stream *as;
+
+	as = snd_usb_find_suppported_substream(card_idx, params, direction);
+	if (!as)
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_find_supported_format);
+
+/**
+ * snd_soc_usb_allocate_port() - allocate a SoC USB port for offloading support
+ * @component: USB DPCM backend DAI component
+ * @data: private data
+ *
+ * Allocate and initialize a SoC USB port.  The SoC USB port is used to communicate
+ * different USB audio devices attached, in order to start audio offloading handled
+ * by an ASoC entity.  USB device plug in/out events are signaled with a
+ * notification, but don't directly impact the memory allocated for the SoC USB
+ * port.
+ *
+ */
+struct snd_soc_usb *snd_soc_usb_allocate_port(struct snd_soc_component *component,
+					      void *data)
+{
+	struct snd_soc_usb *usb;
+
+	usb = kzalloc(sizeof(*usb), GFP_KERNEL);
+	if (!usb)
+		return ERR_PTR(-ENOMEM);
+
+	usb->component = component;
+	usb->priv_data = data;
+
+	return usb;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_allocate_port);
+
+/**
+ * snd_soc_usb_free_port() - free a SoC USB port used for offloading support
+ * @usb: allocated SoC USB port
+ *
+ * Free and remove the SoC USB port from the available list of ports.  This will
+ * ensure that the communication between USB SND and ASoC is halted.
+ *
+ */
+void snd_soc_usb_free_port(struct snd_soc_usb *usb)
+{
+	snd_soc_usb_remove_port(usb);
+	kfree(usb);
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_free_port);
+
+/**
+ * snd_soc_usb_add_port() - Add a USB backend port
+ * @usb: soc usb port to add
+ *
+ * Register a USB backend DAI link to the USB SoC framework.  Memory is allocated
+ * as part of the USB backend DAI link.
+ *
+ */
+void snd_soc_usb_add_port(struct snd_soc_usb *usb)
+{
+	mutex_lock(&ctx_mutex);
+	list_add_tail(&usb->list, &usb_ctx_list);
+	mutex_unlock(&ctx_mutex);
+
+	snd_usb_rediscover_devices();
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_add_port);
+
+/**
+ * snd_soc_usb_remove_port() - Remove a USB backend port
+ * @usb: soc usb port to remove
+ *
+ * Remove a USB backend DAI link from USB SoC.  Memory is freed when USB backend
+ * DAI is removed, or when snd_soc_usb_free_port() is called.
+ *
+ */
+void snd_soc_usb_remove_port(struct snd_soc_usb *usb)
+{
+	struct snd_soc_usb *ctx, *tmp;
+
+	mutex_lock(&ctx_mutex);
+	list_for_each_entry_safe(ctx, tmp, &usb_ctx_list, list) {
+		if (ctx == usb) {
+			list_del(&ctx->list);
+			break;
+		}
+	}
+	mutex_unlock(&ctx_mutex);
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_remove_port);
+
+/**
+ * snd_soc_usb_connect() - Notification of USB device connection
+ * @usbdev: USB bus device
+ * @sdev: USB SND device to add
+ *
+ * Notify of a new USB SND device connection.  The sdev->card_idx can be used to
+ * handle how the DPCM backend selects, which device to enable USB offloading
+ * on.
+ *
+ */
+int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev)
+{
+	struct snd_soc_usb *ctx;
+
+	if (!usbdev)
+		return -ENODEV;
+
+	mutex_lock(&ctx_mutex);
+	ctx = snd_soc_find_usb_ctx(usbdev);
+	if (!ctx)
+		goto exit;
+
+	if (ctx->connection_status_cb)
+		ctx->connection_status_cb(ctx, sdev, true);
+
+exit:
+	mutex_unlock(&ctx_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_connect);
+
+/**
+ * snd_soc_usb_disconnect() - Notification of USB device disconnection
+ * @usbdev: USB bus device
+ * @sdev: USB SND device to remove
+ *
+ * Notify of a new USB SND device disconnection to the USB backend.
+ *
+ */
+int snd_soc_usb_disconnect(struct device *usbdev, struct snd_soc_usb_device *sdev)
+{
+	struct snd_soc_usb *ctx;
+
+	if (!usbdev)
+		return -ENODEV;
+
+	mutex_lock(&ctx_mutex);
+	ctx = snd_soc_find_usb_ctx(usbdev);
+	if (!ctx)
+		goto exit;
+
+	if (ctx->connection_status_cb)
+		ctx->connection_status_cb(ctx, sdev, false);
+
+exit:
+	mutex_unlock(&ctx_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(snd_soc_usb_disconnect);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SoC USB driver for offloading");