[v9,19/34] ALSA: usb-audio: qcom: Introduce QC USB SND offloading support

diff --git a/include/sound/soc-usb.h b/include/sound/soc-usb.h
index 1fa671924018..58c686f4f7ba 100644
--- a/include/sound/soc-usb.h
+++ b/include/sound/soc-usb.h
@@ -39,7 +39,7 @@  struct snd_soc_usb {
 
 int snd_soc_usb_connect(struct device *usbdev, struct snd_soc_usb_device *sdev);
 int snd_soc_usb_disconnect(struct device *usbdev, struct snd_soc_usb_device *sdev);
-void *snd_soc_usb_get_priv_data(struct device *usbdev);
+void *snd_soc_usb_find_priv_data(struct device *usbdev);
 
 struct snd_soc_usb *snd_soc_usb_add_port(struct device *dev, void *priv,
 			int (*connection_cb)(struct snd_soc_usb *usb,
diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
index 4a9569a3a39a..4c842fbe6365 100644
--- a/sound/usb/Kconfig
+++ b/sound/usb/Kconfig
@@ -176,6 +176,21 @@  config SND_BCD2000
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-bcd2000.
 
+config SND_USB_AUDIO_QMI
+	tristate "Qualcomm Audio Offload driver"
+	depends on QCOM_QMI_HELPERS && SND_USB_AUDIO && USB_XHCI_SIDEBAND
+	select SND_PCM
+	help
+	  Say Y here to enable the Qualcomm USB audio offloading feature.
+
+	  This module sets up the required QMI stream enable/disable
+	  responses to requests generated by the audio DSP.  It passes the
+	  USB transfer resource references, so that the audio DSP can issue
+	  USB transfers to the host controller.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-audio-qmi.
+
 source "sound/usb/line6/Kconfig"
 
 endif	# SND_USB
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index db5ff76d0e61..fa624a4052ae 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -34,5 +34,5 @@  obj-$(CONFIG_SND_USB_UA101) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_USX2Y) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o
 
-obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/
+obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/ qcom/
 obj-$(CONFIG_SND_USB_LINE6)	+= line6/
diff --git a/sound/usb/qcom/Makefile b/sound/usb/qcom/Makefile
new file mode 100644
index 000000000000..a81c9b28d484
--- /dev/null
+++ b/sound/usb/qcom/Makefile
@@ -0,0 +1,2 @@ 
+snd-usb-audio-qmi-objs := usb_audio_qmi_v01.o qc_audio_offload.o
+obj-$(CONFIG_SND_USB_AUDIO_QMI) += snd-usb-audio-qmi.o
\ No newline at end of file
diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
new file mode 100644
index 000000000000..320ce3a6688f
--- /dev/null
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -0,0 +1,1843 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/ctype.h>
+#include <linux/moduleparam.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/init.h>
+#include <linux/usb/hcd.h>
+#include <linux/usb/xhci-sideband.h>
+#include <linux/usb/quirks.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/usb/audio-v3.h>
+#include <linux/soc/qcom/qmi.h>
+#include <linux/iommu.h>
+#include <linux/dma-mapping.h>
+#include <linux/dma-map-ops.h>
+#include <sound/q6usboffload.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+
+#include <sound/soc.h>
+#include <sound/soc-usb.h>
+#include "../usbaudio.h"
+#include "../card.h"
+#include "../endpoint.h"
+#include "../helper.h"
+#include "../pcm.h"
+#include "../format.h"
+#include "../power.h"
+#include "usb_audio_qmi_v01.h"
+
+/* Stream disable request timeout during USB device disconnect */
+#define DEV_RELEASE_WAIT_TIMEOUT 10000 /* in ms */
+
+/* Data interval calculation parameters */
+#define BUS_INTERVAL_FULL_SPEED 1000 /* in us */
+#define BUS_INTERVAL_HIGHSPEED_AND_ABOVE 125 /* in us */
+#define MAX_BINTERVAL_ISOC_EP 16
+
+#define QMI_STREAM_REQ_CARD_NUM_MASK 0xffff0000
+#define QMI_STREAM_REQ_DEV_NUM_MASK 0xff00
+#define QMI_STREAM_REQ_DIRECTION 0xff
+
+/* iommu resource parameters and management */
+#define PREPEND_SID_TO_IOVA(iova, sid) ((u64)(((u64)(iova)) | \
+					(((u64)sid) << 32)))
+#define IOVA_BASE 0x1000
+#define IOVA_XFER_RING_BASE (IOVA_BASE + PAGE_SIZE * (SNDRV_CARDS + 1))
+#define IOVA_XFER_BUF_BASE (IOVA_XFER_RING_BASE + PAGE_SIZE * SNDRV_CARDS * 32)
+#define IOVA_XFER_RING_MAX (IOVA_XFER_BUF_BASE - PAGE_SIZE)
+#define IOVA_XFER_BUF_MAX (0xfffff000 - PAGE_SIZE)
+
+#define MAX_XFER_BUFF_LEN (24 * PAGE_SIZE)
+
+struct iova_info {
+	struct list_head list;
+	unsigned long start_iova;
+	size_t size;
+	bool in_use;
+};
+
+struct intf_info {
+	unsigned long data_xfer_ring_va;
+	size_t data_xfer_ring_size;
+	unsigned long sync_xfer_ring_va;
+	size_t sync_xfer_ring_size;
+	unsigned long xfer_buf_va;
+	size_t xfer_buf_size;
+	phys_addr_t xfer_buf_pa;
+	unsigned int data_ep_pipe;
+	unsigned int sync_ep_pipe;
+	u8 *xfer_buf;
+	u8 intf_num;
+	u8 pcm_card_num;
+	u8 pcm_dev_num;
+	u8 direction;
+	bool in_use;
+};
+
+struct uaudio_qmi_dev {
+	struct device *dev;
+	u32 sid;
+	u32 intr_num;
+	struct xhci_ring *sec_ring;
+	struct iommu_domain *domain;
+
+	/* list to keep track of available iova */
+	struct list_head xfer_ring_list;
+	size_t xfer_ring_iova_size;
+	unsigned long curr_xfer_ring_iova;
+	struct list_head xfer_buf_list;
+	size_t xfer_buf_iova_size;
+	unsigned long curr_xfer_buf_iova;
+
+	/* bit fields representing pcm card enabled */
+	unsigned long card_slot;
+	/* indicate event ring mapped or not */
+	bool er_mapped;
+	/* reference count to number of possible consumers */
+	atomic_t qdev_in_use;
+	/* idx to last udev card number plugged in */
+	unsigned int last_card_num;
+};
+
+struct uaudio_dev {
+	struct usb_device *udev;
+	/* audio control interface */
+	struct usb_host_interface *ctrl_intf;
+	unsigned int usb_core_id;
+	atomic_t in_use;
+	struct kref kref;
+	wait_queue_head_t disconnect_wq;
+
+	/* interface specific */
+	int num_intf;
+	struct intf_info *info;
+	struct snd_usb_audio *chip;
+
+	/* xhci sideband */
+	struct xhci_sideband *sb;
+
+	/* SoC USB device */
+	struct snd_soc_usb_device *sdev;
+};
+
+static struct uaudio_dev uadev[SNDRV_CARDS];
+static struct uaudio_qmi_dev *uaudio_qdev;
+static struct uaudio_qmi_svc *uaudio_svc;
+static DEFINE_MUTEX(qdev_mutex);
+
+struct uaudio_qmi_svc {
+	struct qmi_handle *uaudio_svc_hdl;
+	struct work_struct qmi_disconnect_work;
+	struct workqueue_struct *uaudio_wq;
+	struct sockaddr_qrtr client_sq;
+	bool client_connected;
+};
+
+enum mem_type {
+	MEM_EVENT_RING,
+	MEM_XFER_RING,
+	MEM_XFER_BUF,
+};
+
+/* Supported audio formats */
+enum usb_qmi_audio_format {
+	USB_QMI_PCM_FORMAT_S8 = 0,
+	USB_QMI_PCM_FORMAT_U8,
+	USB_QMI_PCM_FORMAT_S16_LE,
+	USB_QMI_PCM_FORMAT_S16_BE,
+	USB_QMI_PCM_FORMAT_U16_LE,
+	USB_QMI_PCM_FORMAT_U16_BE,
+	USB_QMI_PCM_FORMAT_S24_LE,
+	USB_QMI_PCM_FORMAT_S24_BE,
+	USB_QMI_PCM_FORMAT_U24_LE,
+	USB_QMI_PCM_FORMAT_U24_BE,
+	USB_QMI_PCM_FORMAT_S24_3LE,
+	USB_QMI_PCM_FORMAT_S24_3BE,
+	USB_QMI_PCM_FORMAT_U24_3LE,
+	USB_QMI_PCM_FORMAT_U24_3BE,
+	USB_QMI_PCM_FORMAT_S32_LE,
+	USB_QMI_PCM_FORMAT_S32_BE,
+	USB_QMI_PCM_FORMAT_U32_LE,
+	USB_QMI_PCM_FORMAT_U32_BE,
+};
+
+static enum usb_qmi_audio_device_speed_enum_v01
+get_speed_info(enum usb_device_speed udev_speed)
+{
+	switch (udev_speed) {
+	case USB_SPEED_LOW:
+		return USB_QMI_DEVICE_SPEED_LOW_V01;
+	case USB_SPEED_FULL:
+		return USB_QMI_DEVICE_SPEED_FULL_V01;
+	case USB_SPEED_HIGH:
+		return USB_QMI_DEVICE_SPEED_HIGH_V01;
+	case USB_SPEED_SUPER:
+		return USB_QMI_DEVICE_SPEED_SUPER_V01;
+	case USB_SPEED_SUPER_PLUS:
+		return USB_QMI_DEVICE_SPEED_SUPER_PLUS_V01;
+	default:
+		return USB_QMI_DEVICE_SPEED_INVALID_V01;
+	}
+}
+
+static struct snd_usb_substream *find_substream(unsigned int card_num,
+	unsigned int pcm_idx, unsigned int direction)
+{
+	struct snd_usb_stream *as;
+	struct snd_usb_substream *subs = NULL;
+	struct snd_usb_audio *chip;
+
+	chip = uadev[card_num].chip;
+	if (!chip || atomic_read(&chip->shutdown))
+		goto done;
+
+	if (pcm_idx >= chip->pcm_devs)
+		goto done;
+
+	if (direction > SNDRV_PCM_STREAM_CAPTURE)
+		goto done;
+
+	list_for_each_entry(as, &chip->pcm_list, list) {
+		if (as->pcm_index == pcm_idx) {
+			subs = &as->substream[direction];
+			goto done;
+		}
+	}
+
+done:
+	return subs;
+}
+
+static int info_idx_from_ifnum(int card_num, int intf_num, bool enable)
+{
+	int i;
+
+	/*
+	 * default index 0 is used when info is allocated upon
+	 * first enable audio stream req for a pcm device
+	 */
+	if (enable && !uadev[card_num].info)
+		return 0;
+
+	for (i = 0; i < uadev[card_num].num_intf; i++) {
+		if (enable && !uadev[card_num].info[i].in_use)
+			return i;
+		else if (!enable &&
+				uadev[card_num].info[i].intf_num == intf_num)
+			return i;
+	}
+
+	return -EINVAL;
+}
+
+static int get_data_interval_from_si(struct snd_usb_substream *subs,
+	u32 service_interval)
+{
+	unsigned int bus_intval, bus_intval_mult, binterval;
+
+	if (subs->dev->speed >= USB_SPEED_HIGH)
+		bus_intval = BUS_INTERVAL_HIGHSPEED_AND_ABOVE;
+	else
+		bus_intval = BUS_INTERVAL_FULL_SPEED;
+
+	if (service_interval % bus_intval)
+		return -EINVAL;
+
+	bus_intval_mult = service_interval / bus_intval;
+	binterval = ffs(bus_intval_mult);
+	if (!binterval || binterval > MAX_BINTERVAL_ISOC_EP)
+		return -EINVAL;
+
+	/* check if another bit is set then bail out */
+	bus_intval_mult = bus_intval_mult >> binterval;
+	if (bus_intval_mult)
+		return -EINVAL;
+
+	return (binterval - 1);
+}
+
+/* maps audio format received over QMI to asound.h based pcm format */
+static snd_pcm_format_t map_pcm_format(enum usb_qmi_audio_format fmt_received)
+{
+	switch (fmt_received) {
+	case USB_QMI_PCM_FORMAT_S8:
+		return SNDRV_PCM_FORMAT_S8;
+	case USB_QMI_PCM_FORMAT_U8:
+		return SNDRV_PCM_FORMAT_U8;
+	case USB_QMI_PCM_FORMAT_S16_LE:
+		return SNDRV_PCM_FORMAT_S16_LE;
+	case USB_QMI_PCM_FORMAT_S16_BE:
+		return SNDRV_PCM_FORMAT_S16_BE;
+	case USB_QMI_PCM_FORMAT_U16_LE:
+		return SNDRV_PCM_FORMAT_U16_LE;
+	case USB_QMI_PCM_FORMAT_U16_BE:
+		return SNDRV_PCM_FORMAT_U16_BE;
+	case USB_QMI_PCM_FORMAT_S24_LE:
+		return SNDRV_PCM_FORMAT_S24_LE;
+	case USB_QMI_PCM_FORMAT_S24_BE:
+		return SNDRV_PCM_FORMAT_S24_BE;
+	case USB_QMI_PCM_FORMAT_U24_LE:
+		return SNDRV_PCM_FORMAT_U24_LE;
+	case USB_QMI_PCM_FORMAT_U24_BE:
+		return SNDRV_PCM_FORMAT_U24_BE;
+	case USB_QMI_PCM_FORMAT_S24_3LE:
+		return SNDRV_PCM_FORMAT_S24_3LE;
+	case USB_QMI_PCM_FORMAT_S24_3BE:
+		return SNDRV_PCM_FORMAT_S24_3BE;
+	case USB_QMI_PCM_FORMAT_U24_3LE:
+		return SNDRV_PCM_FORMAT_U24_3LE;
+	case USB_QMI_PCM_FORMAT_U24_3BE:
+		return SNDRV_PCM_FORMAT_U24_3BE;
+	case USB_QMI_PCM_FORMAT_S32_LE:
+		return SNDRV_PCM_FORMAT_S32_LE;
+	case USB_QMI_PCM_FORMAT_S32_BE:
+		return SNDRV_PCM_FORMAT_S32_BE;
+	case USB_QMI_PCM_FORMAT_U32_LE:
+		return SNDRV_PCM_FORMAT_U32_LE;
+	case USB_QMI_PCM_FORMAT_U32_BE:
+		return SNDRV_PCM_FORMAT_U32_BE;
+	default:
+		/*
+		 * We expect the caller to do input validation so we should
+		 * never hit this. But we do have to return a proper
+		 * snd_pcm_format_t value due to the __bitwise attribute; so
+		 * just return the equivalent of 0 in case of bad input.
+		 */
+		return SNDRV_PCM_FORMAT_S8;
+	}
+}
+
+/* Offloading IOMMU management */
+static unsigned long uaudio_get_iova(unsigned long *curr_iova,
+	size_t *curr_iova_size, struct list_head *head, size_t size)
+{
+	struct iova_info *info, *new_info = NULL;
+	struct list_head *curr_head;
+	unsigned long va = 0;
+	size_t tmp_size = size;
+	bool found = false;
+
+	if (size % PAGE_SIZE) {
+		dev_dbg(uaudio_qdev->dev, "size %zu is not page size multiple\n",
+			size);
+		goto done;
+	}
+
+	if (size > *curr_iova_size) {
+		dev_dbg(uaudio_qdev->dev, "size %zu > curr size %zu\n",
+			size, *curr_iova_size);
+		goto done;
+	}
+	if (*curr_iova_size == 0) {
+		dev_dbg(uaudio_qdev->dev, "iova mapping is full\n");
+		goto done;
+	}
+
+	list_for_each_entry(info, head, list) {
+		/* exact size iova_info */
+		if (!info->in_use && info->size == size) {
+			info->in_use = true;
+			va = info->start_iova;
+			*curr_iova_size -= size;
+			found = true;
+			dev_dbg(uaudio_qdev->dev, "exact size: %zu found\n", size);
+			goto done;
+		} else if (!info->in_use && tmp_size >= info->size) {
+			if (!new_info)
+				new_info = info;
+			dev_dbg(uaudio_qdev->dev, "partial size: %zu found\n",
+					info->size);
+			tmp_size -= info->size;
+			if (tmp_size)
+				continue;
+
+			va = new_info->start_iova;
+			for (curr_head = &new_info->list; curr_head !=
+			&info->list; curr_head = curr_head->next) {
+				new_info = list_entry(curr_head, struct
+						iova_info, list);
+				new_info->in_use = true;
+			}
+			info->in_use = true;
+			*curr_iova_size -= size;
+			found = true;
+			goto done;
+		} else {
+			/* iova region in use */
+			new_info = NULL;
+			tmp_size = size;
+		}
+	}
+
+	info = kzalloc(sizeof(struct iova_info), GFP_KERNEL);
+	if (!info) {
+		va = 0;
+		goto done;
+	}
+
+	va = info->start_iova = *curr_iova;
+	info->size = size;
+	info->in_use = true;
+	*curr_iova += size;
+	*curr_iova_size -= size;
+	found = true;
+	list_add_tail(&info->list, head);
+
+done:
+	if (!found)
+		dev_err(uaudio_qdev->dev, "unable to find %zu size iova\n",
+			size);
+	else
+		dev_dbg(uaudio_qdev->dev,
+			"va:0x%08lx curr_iova:0x%08lx curr_iova_size:%zu\n",
+			va, *curr_iova, *curr_iova_size);
+
+	return va;
+}
+
+static void uaudio_put_iova(unsigned long va, size_t size, struct list_head
+	*head, size_t *curr_iova_size)
+{
+	struct iova_info *info;
+	size_t tmp_size = size;
+	bool found = false;
+
+	list_for_each_entry(info, head, list) {
+		if (info->start_iova == va) {
+			if (!info->in_use) {
+				dev_err(uaudio_qdev->dev, "va %lu is not in use\n",
+					va);
+				return;
+			}
+			found = true;
+			info->in_use = false;
+			if (info->size == size)
+				goto done;
+		}
+
+		if (found && tmp_size >= info->size) {
+			info->in_use = false;
+			tmp_size -= info->size;
+			if (!tmp_size)
+				goto done;
+		}
+	}
+
+	if (!found) {
+		dev_err(uaudio_qdev->dev, "unable to find the va %lu\n", va);
+		return;
+	}
+done:
+	*curr_iova_size += size;
+	dev_dbg(uaudio_qdev->dev, "curr_iova_size %zu\n", *curr_iova_size);
+}
+
+/**
+ * uaudio_iommu_unmap() - unmaps iommu memory for adsp
+ * @mtype: ring type
+ * @va: virtual address to unmap
+ * @iova_size: region size
+ * @mapped_iova_size: mapped region size
+ *
+ * Unmaps the memory region that was previously assigned to the adsp.
+ *
+ */
+static void uaudio_iommu_unmap(enum mem_type mtype, unsigned long va,
+	size_t iova_size, size_t mapped_iova_size)
+{
+	size_t umap_size;
+	bool unmap = true;
+
+	if (!va || !iova_size)
+		return;
+
+	switch (mtype) {
+	case MEM_EVENT_RING:
+		if (uaudio_qdev->er_mapped)
+			uaudio_qdev->er_mapped = false;
+		else
+			unmap = false;
+		break;
+
+	case MEM_XFER_RING:
+		uaudio_put_iova(va, iova_size, &uaudio_qdev->xfer_ring_list,
+		&uaudio_qdev->xfer_ring_iova_size);
+		break;
+	case MEM_XFER_BUF:
+		uaudio_put_iova(va, iova_size, &uaudio_qdev->xfer_buf_list,
+		&uaudio_qdev->xfer_buf_iova_size);
+		break;
+	default:
+		dev_err(uaudio_qdev->dev, "unknown mem type %d\n", mtype);
+		unmap = false;
+	}
+
+	if (!unmap || !mapped_iova_size)
+		return;
+
+	dev_dbg(uaudio_qdev->dev, "type %d: unmap iova 0x%08lx size %zu\n",
+		mtype, va, mapped_iova_size);
+
+	umap_size = iommu_unmap(uaudio_qdev->domain, va, mapped_iova_size);
+	if (umap_size != mapped_iova_size)
+		dev_err(uaudio_qdev->dev,
+			"unmapped size %zu for iova 0x%08lx of mapped size %zu\n",
+			umap_size, va, mapped_iova_size);
+}
+
+/**
+ * uaudio_iommu_map() - maps iommu memory for adsp
+ * @mtype: ring type
+ * @dma_coherent: dma coherent
+ * @pa: physical address for ring/buffer
+ * @size: size of memory region
+ * @sgt: sg table for memory region
+ *
+ * Maps the XHCI related resources to a memory region that is assigned to be
+ * used by the adsp.  This will be mapped to the domain, which is created by
+ * the ASoC USB backend driver.
+ *
+ */
+static unsigned long uaudio_iommu_map(enum mem_type mtype, bool dma_coherent,
+		phys_addr_t pa, size_t size, struct sg_table *sgt)
+{
+	unsigned long va_sg, va = 0;
+	bool map = true;
+	int i, ret;
+	size_t sg_len, total_len = 0;
+	struct scatterlist *sg;
+	phys_addr_t pa_sg;
+	int prot = IOMMU_READ | IOMMU_WRITE;
+
+	if (dma_coherent)
+		prot |= IOMMU_CACHE;
+
+	switch (mtype) {
+	case MEM_EVENT_RING:
+		va = IOVA_BASE;
+		/* er already mapped */
+		if (uaudio_qdev->er_mapped)
+			map = false;
+		break;
+	case MEM_XFER_RING:
+		va = uaudio_get_iova(&uaudio_qdev->curr_xfer_ring_iova,
+		&uaudio_qdev->xfer_ring_iova_size, &uaudio_qdev->xfer_ring_list,
+		size);
+		break;
+	case MEM_XFER_BUF:
+		va = uaudio_get_iova(&uaudio_qdev->curr_xfer_buf_iova,
+		&uaudio_qdev->xfer_buf_iova_size, &uaudio_qdev->xfer_buf_list,
+		size);
+		break;
+	default:
+		dev_err(uaudio_qdev->dev, "unknown mem type %d\n", mtype);
+	}
+
+	if (!va || !map)
+		goto done;
+
+	if (!sgt)
+		goto skip_sgt_map;
+
+	va_sg = va;
+	for_each_sg(sgt->sgl, sg, sgt->nents, i) {
+		sg_len = PAGE_ALIGN(sg->offset + sg->length);
+		pa_sg = page_to_phys(sg_page(sg));
+		ret = iommu_map(uaudio_qdev->domain, va_sg, pa_sg, sg_len,
+				prot, GFP_KERNEL);
+		if (ret) {
+			dev_err(uaudio_qdev->dev, "mapping failed ret%d\n", ret);
+			dev_err(uaudio_qdev->dev,
+				"type:%d, pa:%pa iova:0x%08lx sg_len:%zu\n",
+				mtype, &pa_sg, va_sg, sg_len);
+			uaudio_iommu_unmap(MEM_XFER_BUF, va, size, total_len);
+			va = 0;
+			goto done;
+		}
+		dev_dbg(uaudio_qdev->dev,
+			"type:%d map pa:%pa to iova:0x%08lx len:%zu offset:%u\n",
+			mtype, &pa_sg, va_sg, sg_len, sg->offset);
+		va_sg += sg_len;
+		total_len += sg_len;
+	}
+
+	if (size != total_len) {
+		dev_err(uaudio_qdev->dev, "iova size %zu != mapped iova size %zu\n",
+			size, total_len);
+		uaudio_iommu_unmap(MEM_XFER_BUF, va, size, total_len);
+		va = 0;
+	}
+	return va;
+
+skip_sgt_map:
+	dev_dbg(uaudio_qdev->dev, "type:%d map pa:%pa to iova:0x%08lx size:%zu\n",
+		mtype, &pa, va, size);
+
+	ret = iommu_map(uaudio_qdev->domain, va, pa, size, prot, GFP_KERNEL);
+	if (ret)
+		dev_err(uaudio_qdev->dev,
+			"failed to map pa:%pa iova:0x%lx type:%d ret:%d\n",
+			&pa, va, mtype, ret);
+done:
+	return va;
+}
+
+/* looks up alias, if any, for controller DT node and returns the index */
+static int usb_get_controller_id(struct usb_device *udev)
+{
+	if (udev->bus->sysdev && udev->bus->sysdev->of_node)
+		return of_alias_get_id(udev->bus->sysdev->of_node, "usb");
+
+	return -ENODEV;
+}
+
+/**
+ * uaudio_dev_intf_cleanup() - cleanup transfer resources
+ * @udev: usb device
+ * @info: usb offloading interface
+ *
+ * Cleans up the transfer ring related resources which are assigned per
+ * endpoint from XHCI.  This is invoked when the USB endpoints are no
+ * longer in use by the adsp.
+ *
+ */
+static void uaudio_dev_intf_cleanup(struct usb_device *udev,
+	struct intf_info *info)
+{
+	uaudio_iommu_unmap(MEM_XFER_RING, info->data_xfer_ring_va,
+		info->data_xfer_ring_size, info->data_xfer_ring_size);
+	info->data_xfer_ring_va = 0;
+	info->data_xfer_ring_size = 0;
+
+	uaudio_iommu_unmap(MEM_XFER_RING, info->sync_xfer_ring_va,
+		info->sync_xfer_ring_size, info->sync_xfer_ring_size);
+	info->sync_xfer_ring_va = 0;
+	info->sync_xfer_ring_size = 0;
+
+	uaudio_iommu_unmap(MEM_XFER_BUF, info->xfer_buf_va,
+		info->xfer_buf_size, info->xfer_buf_size);
+	info->xfer_buf_va = 0;
+
+	usb_free_coherent(udev, info->xfer_buf_size,
+		info->xfer_buf, info->xfer_buf_pa);
+	info->xfer_buf_size = 0;
+	info->xfer_buf = NULL;
+	info->xfer_buf_pa = 0;
+
+	info->in_use = false;
+}
+
+/**
+ * uaudio_event_ring_cleanup_free() - cleanup secondary event ring
+ * @dev: usb offload device
+ *
+ * Cleans up the secondary event ring that was requested.  This will
+ * occur when the adsp is no longer transferring data on the USB bus
+ * across all endpoints.
+ *
+ */
+static void uaudio_event_ring_cleanup_free(struct uaudio_dev *dev)
+{
+	clear_bit(dev->chip->card->number, &uaudio_qdev->card_slot);
+	/* all audio devices are disconnected */
+	if (!uaudio_qdev->card_slot) {
+		uaudio_iommu_unmap(MEM_EVENT_RING, IOVA_BASE, PAGE_SIZE,
+			PAGE_SIZE);
+		xhci_sideband_remove_interrupter(uadev[dev->chip->card->number].sb);
+	}
+}
+
+static void uaudio_dev_cleanup(struct uaudio_dev *dev)
+{
+	int if_idx;
+
+	if (!dev->udev)
+		return;
+
+	/* free xfer buffer and unmap xfer ring and buf per interface */
+	for (if_idx = 0; if_idx < dev->num_intf; if_idx++) {
+		if (!dev->info[if_idx].in_use)
+			continue;
+		uaudio_dev_intf_cleanup(dev->udev, &dev->info[if_idx]);
+		dev_dbg(uaudio_qdev->dev, "release resources: intf# %d card# %d\n",
+			dev->info[if_idx].intf_num, dev->chip->card->number);
+	}
+
+	dev->num_intf = 0;
+
+	/* free interface info */
+	kfree(dev->info);
+	dev->info = NULL;
+	uaudio_event_ring_cleanup_free(dev);
+	dev->udev = NULL;
+}
+
+/**
+ * disable_audio_stream() - disable usb snd endpoints
+ * @subs: usb substream
+ *
+ * Closes the USB SND endpoints associated with the current audio stream
+ * used.  This will decrement the USB SND endpoint opened reference count.
+ *
+ */
+static void disable_audio_stream(struct snd_usb_substream *subs)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+
+	snd_usb_hw_free(subs);
+	snd_usb_autosuspend(chip);
+}
+
+/* QMI service disconnect handlers */
+static void qmi_disconnect_work(struct work_struct *w)
+{
+	struct intf_info *info;
+	int idx, if_idx;
+	struct snd_usb_substream *subs;
+	struct snd_usb_audio *chip;
+
+	mutex_lock(&qdev_mutex);
+	/* find all active intf for set alt 0 and cleanup usb audio dev */
+	for (idx = 0; idx < SNDRV_CARDS; idx++) {
+		if (!atomic_read(&uadev[idx].in_use))
+			continue;
+
+		chip = uadev[idx].chip;
+		for (if_idx = 0; if_idx < uadev[idx].num_intf; if_idx++) {
+			if (!uadev[idx].info || !uadev[idx].info[if_idx].in_use)
+				continue;
+			info = &uadev[idx].info[if_idx];
+			subs = find_substream(info->pcm_card_num,
+						info->pcm_dev_num,
+						info->direction);
+			if (!subs || !chip || atomic_read(&chip->shutdown)) {
+				dev_err(&subs->dev->dev,
+					"no sub for c#%u dev#%u dir%u\n",
+					info->pcm_card_num,
+					info->pcm_dev_num,
+					info->direction);
+				continue;
+			}
+			disable_audio_stream(subs);
+		}
+		atomic_set(&uadev[idx].in_use, 0);
+		mutex_lock(&chip->mutex);
+		uaudio_dev_cleanup(&uadev[idx]);
+		mutex_unlock(&chip->mutex);
+	}
+	mutex_unlock(&qdev_mutex);
+}
+
+/**
+ * qmi_bye_cb() - qmi bye message callback
+ * @handle: QMI handle
+ * @node: id of the dying node
+ *
+ * This callback is invoked when the QMI bye control message is received
+ * from the QMI client.  Handle the message accordingly by ensuring that
+ * the USB offload path is disabled and cleaned up.  At this point, ADSP
+ * is not utilizing the USB bus.
+ *
+ */
+static void qmi_bye_cb(struct qmi_handle *handle, unsigned int node)
+{
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+
+	if (svc->uaudio_svc_hdl != handle)
+		return;
+
+	if (svc->client_connected && svc->client_sq.sq_node == node) {
+		queue_work(svc->uaudio_wq, &svc->qmi_disconnect_work);
+		svc->client_sq.sq_node = 0;
+		svc->client_sq.sq_port = 0;
+		svc->client_sq.sq_family = 0;
+		svc->client_connected = false;
+	}
+}
+
+/**
+ * qmi_svc_disconnect_cb() - qmi client disconnected
+ * @handle: QMI handle
+ * @node: id of the dying node
+ * @port: port of the dying client
+ *
+ * Invoked when the remote QMI client is disconnected.  Handle this event
+ * the same way as when the QMI bye message is received.  This will ensure
+ * the USB offloading path is disabled and cleaned up.
+ *
+ */
+static void qmi_svc_disconnect_cb(struct qmi_handle *handle,
+				  unsigned int node, unsigned int port)
+{
+	struct uaudio_qmi_svc *svc;
+
+	if (uaudio_svc == NULL)
+		return;
+
+	svc = uaudio_svc;
+	if (svc->uaudio_svc_hdl != handle)
+		return;
+
+	if (svc->client_connected && svc->client_sq.sq_node == node &&
+			svc->client_sq.sq_port == port) {
+		queue_work(svc->uaudio_wq, &svc->qmi_disconnect_work);
+		svc->client_sq.sq_node = 0;
+		svc->client_sq.sq_port = 0;
+		svc->client_sq.sq_family = 0;
+		svc->client_connected = false;
+	}
+}
+
+/* QMI client callback handlers from QMI interface */
+static struct qmi_ops uaudio_svc_ops_options = {
+	.bye = qmi_bye_cb,
+	.del_client = qmi_svc_disconnect_cb,
+};
+
+/* kref release callback when all streams are disabled */
+static void uaudio_dev_release(struct kref *kref)
+{
+	struct uaudio_dev *dev = container_of(kref, struct uaudio_dev, kref);
+
+	uaudio_event_ring_cleanup_free(dev);
+	atomic_set(&dev->in_use, 0);
+	wake_up(&dev->disconnect_wq);
+}
+
+/**
+ * enable_audio_stream() - enable usb snd endpoints
+ * @subs: usb substream
+ * @pcm_format: pcm format requested
+ * @channels: number of channels
+ * @cur_rate: sample rate
+ * @datainterval: interval
+ *
+ * Opens all USB SND endpoints used for the data interface.  This will increment
+ * the USB SND endpoint's opened count.  Requests to keep the interface resumed
+ * until the audio stream is stopped.  Will issue the USB set interface control
+ * message to enable the data interface.
+ *
+ */
+static int enable_audio_stream(struct snd_usb_substream *subs,
+				snd_pcm_format_t pcm_format,
+				unsigned int channels, unsigned int cur_rate,
+				int datainterval)
+{
+	struct snd_usb_audio *chip = subs->stream->chip;
+	struct snd_pcm_hw_params params;
+	struct snd_mask *m;
+	struct snd_interval *i;
+	int ret;
+
+	_snd_pcm_hw_params_any(&params);
+
+	m = hw_param_mask(&params, SNDRV_PCM_HW_PARAM_FORMAT);
+	snd_mask_leave(m, pcm_format);
+
+	i = hw_param_interval(&params, SNDRV_PCM_HW_PARAM_CHANNELS);
+	snd_interval_setinteger(i);
+	i->min = i->max = channels;
+
+	i = hw_param_interval(&params, SNDRV_PCM_HW_PARAM_RATE);
+	snd_interval_setinteger(i);
+	i->min = i->max = cur_rate;
+
+	pm_runtime_barrier(&chip->intf[0]->dev);
+	snd_usb_autoresume(chip);
+
+	ret = snd_usb_hw_params(subs, &params);
+	if (ret < 0)
+		goto put_suspend;
+
+	if (!atomic_read(&chip->shutdown)) {
+		ret = snd_usb_lock_shutdown(chip);
+		if (ret < 0)
+			goto detach_ep;
+
+		if (subs->sync_endpoint) {
+			ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
+			if (ret < 0)
+				goto unlock;
+		}
+
+		ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
+		if (ret < 0)
+			goto unlock;
+
+		snd_usb_unlock_shutdown(chip);
+
+		dev_dbg(uaudio_qdev->dev,
+			"selected %s iface:%d altsetting:%d datainterval:%dus\n",
+			subs->direction ? "capture" : "playback",
+			subs->cur_audiofmt->iface, subs->cur_audiofmt->altsetting,
+			(1 << subs->cur_audiofmt->datainterval) *
+			(subs->dev->speed >= USB_SPEED_HIGH ?
+			BUS_INTERVAL_HIGHSPEED_AND_ABOVE :
+			BUS_INTERVAL_FULL_SPEED));
+	}
+
+	return 0;
+
+unlock:
+	snd_usb_unlock_shutdown(chip);
+
+detach_ep:
+	snd_usb_hw_free(subs);
+
+put_suspend:
+	snd_usb_autosuspend(chip);
+
+	return ret;
+}
+
+/* returns usb hcd sysdev */
+static struct device *usb_get_usb_backend(struct usb_device *udev)
+{
+	if (udev->bus->sysdev && udev->bus->sysdev->of_node)
+		return udev->bus->sysdev;
+
+	return NULL;
+}
+
+/**
+ * prepare_qmi_response() - prepare stream enable response
+ * @subs: usb substream
+ * @req_msg: QMI request message
+ * @resp: QMI response buffer
+ * @info_idx: usb interface array index
+ *
+ * Prepares the QMI response for a USB QMI stream enable request.  Will parse
+ * out the parameters within the stream enable request, in order to match
+ * requested audio profile to the ones exposed by the USB device connected.
+ *
+ * In addition, will fetch the XHCI transfer resources needed for the handoff to
+ * happen.  This includes, transfer ring and buffer addresses and secondary event
+ * ring address.  These parameters will be communicated as part of the USB QMI
+ * stream enable response.
+ *
+ */
+static int prepare_qmi_response(struct snd_usb_substream *subs,
+		struct qmi_uaudio_stream_req_msg_v01 *req_msg,
+		struct qmi_uaudio_stream_resp_msg_v01 *resp, int info_idx)
+{
+	struct usb_interface *iface;
+	struct usb_host_interface *alts;
+	struct usb_interface_descriptor *altsd;
+	struct usb_interface_assoc_descriptor *assoc;
+	struct usb_host_endpoint *ep;
+	struct uac_format_type_i_continuous_descriptor *fmt;
+	struct uac_format_type_i_discrete_descriptor *fmt_v1;
+	struct uac_format_type_i_ext_descriptor *fmt_v2;
+	struct uac1_as_header_descriptor *as;
+	struct q6usb_offload *data;
+	int ret;
+	int protocol, card_num, pcm_dev_num;
+	void *hdr_ptr;
+	u8 *xfer_buf;
+	unsigned int data_ep_pipe = 0, sync_ep_pipe = 0;
+	u32 len, mult, remainder, xfer_buf_len;
+	unsigned long va, tr_data_va = 0, tr_sync_va = 0;
+	phys_addr_t xhci_pa, xfer_buf_pa, tr_data_pa = 0, tr_sync_pa = 0;
+	struct sg_table *sgt;
+	struct sg_table xfer_buf_sgt;
+	struct page *pg;
+	bool dma_coherent;
+
+	iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
+	if (!iface) {
+		dev_err(uaudio_qdev->dev, "interface # %d does not exist\n",
+			subs->cur_audiofmt->iface);
+		ret = -ENODEV;
+		goto err;
+	}
+
+	assoc = iface->intf_assoc;
+	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
+	xfer_buf_len = req_msg->xfer_buff_size;
+	card_num = uaudio_qdev->last_card_num;
+
+	alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
+	altsd = get_iface_desc(alts);
+	protocol = altsd->bInterfaceProtocol;
+
+	/* get format type */
+	if (protocol != UAC_VERSION_3) {
+		fmt = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+				UAC_FORMAT_TYPE);
+		if (!fmt) {
+			dev_err(uaudio_qdev->dev,
+				"%u:%d : no UAC_FORMAT_TYPE desc\n",
+				subs->cur_audiofmt->iface,
+				subs->cur_audiofmt->altset_idx);
+			ret = -ENODEV;
+			goto err;
+		}
+	}
+
+	if (!uadev[card_num].ctrl_intf) {
+		dev_err(uaudio_qdev->dev, "audio ctrl intf info not cached\n");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	if (protocol != UAC_VERSION_3) {
+		hdr_ptr = snd_usb_find_csint_desc(uadev[card_num].ctrl_intf->extra,
+				uadev[card_num].ctrl_intf->extralen, NULL,
+				UAC_HEADER);
+		if (!hdr_ptr) {
+			dev_err(uaudio_qdev->dev, "no UAC_HEADER desc\n");
+			ret = -ENODEV;
+			goto err;
+		}
+	}
+
+	if (protocol == UAC_VERSION_1) {
+		struct uac1_ac_header_descriptor *uac1_hdr = hdr_ptr;
+
+		as = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
+			UAC_AS_GENERAL);
+		if (!as) {
+			dev_err(uaudio_qdev->dev,
+				"%u:%d : no UAC_AS_GENERAL desc\n",
+				subs->cur_audiofmt->iface,
+				subs->cur_audiofmt->altset_idx);
+			ret = -ENODEV;
+			goto err;
+		}
+		resp->data_path_delay = as->bDelay;
+		resp->data_path_delay_valid = 1;
+		fmt_v1 = (struct uac_format_type_i_discrete_descriptor *)fmt;
+		resp->usb_audio_subslot_size = fmt_v1->bSubframeSize;
+		resp->usb_audio_subslot_size_valid = 1;
+
+		resp->usb_audio_spec_revision = le16_to_cpu(uac1_hdr->bcdADC);
+		resp->usb_audio_spec_revision_valid = 1;
+	} else if (protocol == UAC_VERSION_2) {
+		struct uac2_ac_header_descriptor *uac2_hdr = hdr_ptr;
+
+		fmt_v2 = (struct uac_format_type_i_ext_descriptor *)fmt;
+		resp->usb_audio_subslot_size = fmt_v2->bSubslotSize;
+		resp->usb_audio_subslot_size_valid = 1;
+
+		resp->usb_audio_spec_revision = le16_to_cpu(uac2_hdr->bcdADC);
+		resp->usb_audio_spec_revision_valid = 1;
+	} else if (protocol == UAC_VERSION_3) {
+		if (assoc->bFunctionSubClass ==
+					UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0) {
+			dev_err(uaudio_qdev->dev, "full adc is not supported\n");
+			ret = -EINVAL;
+		}
+
+		switch (le16_to_cpu(get_endpoint(alts, 0)->wMaxPacketSize)) {
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_16:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_16: {
+			resp->usb_audio_subslot_size = 0x2;
+			break;
+		}
+
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_SYNC_STEREO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_MONO_24:
+		case UAC3_BADD_EP_MAXPSIZE_ASYNC_STEREO_24: {
+			resp->usb_audio_subslot_size = 0x3;
+			break;
+		}
+
+		default:
+			dev_err(uaudio_qdev->dev,
+				"%d: %u: Invalid wMaxPacketSize\n",
+				subs->cur_audiofmt->iface,
+				subs->cur_audiofmt->altset_idx);
+			ret = -EINVAL;
+			goto err;
+		}
+		resp->usb_audio_subslot_size_valid = 1;
+	} else {
+		dev_err(uaudio_qdev->dev, "unknown protocol version %x\n",
+			protocol);
+		ret = -ENODEV;
+		goto err;
+	}
+
+	resp->slot_id = subs->dev->slot_id;
+	resp->slot_id_valid = 1;
+
+	memcpy(&resp->std_as_opr_intf_desc, &alts->desc, sizeof(alts->desc));
+	resp->std_as_opr_intf_desc_valid = 1;
+
+	ep = usb_pipe_endpoint(subs->dev, subs->data_endpoint->pipe);
+	if (!ep) {
+		dev_err(uaudio_qdev->dev, "data ep # %d context is null\n",
+			subs->data_endpoint->ep_num);
+		ret = -ENODEV;
+		goto err;
+	}
+	data_ep_pipe = subs->data_endpoint->pipe;
+	memcpy(&resp->std_as_data_ep_desc, &ep->desc, sizeof(ep->desc));
+	resp->std_as_data_ep_desc_valid = 1;
+
+	ret = xhci_sideband_add_endpoint(uadev[card_num].sb, ep);
+	if (ret < 0) {
+		dev_err(uaudio_qdev->dev, "failed to add data ep to sideband\n");
+		ret = -ENODEV;
+		goto err;
+	}
+
+	sgt = xhci_sideband_get_endpoint_buffer(uadev[card_num].sb, ep);
+	if (!sgt) {
+		dev_err(uaudio_qdev->dev, "failed to get data ep ring address\n");
+		ret = -ENODEV;
+		goto drop_data_ep;
+	}
+
+	pg = sg_page(sgt->sgl);
+	tr_data_pa = page_to_phys(pg);
+	resp->xhci_mem_info.tr_data.pa = sg_dma_address(sgt->sgl);
+	sg_free_table(sgt);
+
+	if (subs->sync_endpoint) {
+		ep = usb_pipe_endpoint(subs->dev, subs->sync_endpoint->pipe);
+		if (!ep) {
+			dev_err(uaudio_qdev->dev, "implicit fb on data ep\n");
+			goto skip_sync_ep;
+		}
+		sync_ep_pipe = subs->sync_endpoint->pipe;
+		memcpy(&resp->std_as_sync_ep_desc, &ep->desc, sizeof(ep->desc));
+		resp->std_as_sync_ep_desc_valid = 1;
+
+		ret = xhci_sideband_add_endpoint(uadev[card_num].sb, ep);
+		if (ret < 0) {
+			dev_err(uaudio_qdev->dev,
+				"failed to add sync ep to sideband\n");
+			ret = -ENODEV;
+			goto drop_data_ep;
+		}
+
+		sgt = xhci_sideband_get_endpoint_buffer(uadev[card_num].sb, ep);
+		if (!sgt) {
+			dev_err(uaudio_qdev->dev, "failed to get sync ep ring address\n");
+			ret = -ENODEV;
+			goto drop_sync_ep;
+		}
+
+		pg = sg_page(sgt->sgl);
+		tr_sync_pa = page_to_phys(pg);
+		resp->xhci_mem_info.tr_sync.pa = sg_dma_address(sgt->sgl);
+		sg_free_table(sgt);
+	}
+
+skip_sync_ep:
+	data = snd_soc_usb_find_priv_data(usb_get_usb_backend(subs->dev));
+	if (!data)
+		goto drop_sync_ep;
+
+	uaudio_qdev->domain = data->domain;
+	uaudio_qdev->sid = data->sid;
+	uaudio_qdev->intr_num = data->intr_num;
+	uaudio_qdev->dev = data->dev;
+
+	resp->interrupter_num_valid = 1;
+	resp->controller_num_valid = 0;
+	ret = usb_get_controller_id(subs->dev);
+	if (ret >= 0) {
+		resp->controller_num = ret;
+		resp->controller_num_valid = 1;
+	}
+	/* map xhci data structures PA memory to iova */
+	dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);
+
+	/* event ring */
+	ret = xhci_sideband_create_interrupter(uadev[card_num].sb, uaudio_qdev->intr_num);
+	if (ret < 0) {
+		dev_err(uaudio_qdev->dev, "failed to fetch interrupter\n");
+		ret = -ENODEV;
+		goto drop_sync_ep;
+	}
+
+	sgt = xhci_sideband_get_event_buffer(uadev[card_num].sb);
+	if (!sgt) {
+		dev_err(uaudio_qdev->dev, "failed to get event ring address\n");
+		ret = -ENODEV;
+		goto free_sec_ring;
+	}
+
+	xhci_pa = page_to_phys(sg_page(sgt->sgl));
+	resp->xhci_mem_info.evt_ring.pa = sg_dma_address(sgt->sgl);
+	sg_free_table(sgt);
+	if (!xhci_pa) {
+		dev_err(uaudio_qdev->dev,
+			"failed to get sec event ring address\n");
+		ret = -ENODEV;
+		goto free_sec_ring;
+	}
+
+	resp->interrupter_num = xhci_sideband_interrupter_id(uadev[card_num].sb);
+
+	va = uaudio_iommu_map(MEM_EVENT_RING, dma_coherent, xhci_pa, PAGE_SIZE,
+			NULL);
+	if (!va) {
+		ret = -ENOMEM;
+		goto free_sec_ring;
+	}
+
+	resp->xhci_mem_info.evt_ring.va = PREPEND_SID_TO_IOVA(va,
+						uaudio_qdev->sid);
+	resp->xhci_mem_info.evt_ring.size = PAGE_SIZE;
+	uaudio_qdev->er_mapped = true;
+
+	resp->speed_info = get_speed_info(subs->dev->speed);
+	if (resp->speed_info == USB_QMI_DEVICE_SPEED_INVALID_V01) {
+		ret = -ENODEV;
+		goto unmap_er;
+	}
+
+	resp->speed_info_valid = 1;
+
+	/* data transfer ring */
+	va = uaudio_iommu_map(MEM_XFER_RING, dma_coherent, tr_data_pa,
+			PAGE_SIZE, NULL);
+	if (!va) {
+		ret = -ENOMEM;
+		goto unmap_er;
+	}
+
+	tr_data_va = va;
+	resp->xhci_mem_info.tr_data.va = PREPEND_SID_TO_IOVA(va,
+						uaudio_qdev->sid);
+	resp->xhci_mem_info.tr_data.size = PAGE_SIZE;
+
+	/* sync transfer ring */
+	if (!resp->xhci_mem_info.tr_sync.pa)
+		goto skip_sync;
+
+	xhci_pa = resp->xhci_mem_info.tr_sync.pa;
+	va = uaudio_iommu_map(MEM_XFER_RING, dma_coherent, tr_sync_pa,
+			PAGE_SIZE, NULL);
+	if (!va) {
+		ret = -ENOMEM;
+		goto unmap_data;
+	}
+
+	tr_sync_va = va;
+	resp->xhci_mem_info.tr_sync.va = PREPEND_SID_TO_IOVA(va,
+						uaudio_qdev->sid);
+	resp->xhci_mem_info.tr_sync.size = PAGE_SIZE;
+
+skip_sync:
+	/* xfer buffer, multiple of 4K only */
+	if (!xfer_buf_len)
+		xfer_buf_len = PAGE_SIZE;
+
+	mult = xfer_buf_len / PAGE_SIZE;
+	remainder = xfer_buf_len % PAGE_SIZE;
+	len = mult * PAGE_SIZE;
+	len += remainder ? PAGE_SIZE : 0;
+
+	if (len > MAX_XFER_BUFF_LEN) {
+		dev_err(uaudio_qdev->dev,
+			"req buf len %d > max buf len %lu, setting %lu\n",
+			len, MAX_XFER_BUFF_LEN, MAX_XFER_BUFF_LEN);
+		len = MAX_XFER_BUFF_LEN;
+	}
+
+	xfer_buf = usb_alloc_coherent(subs->dev, len, GFP_KERNEL, &xfer_buf_pa);
+	if (!xfer_buf) {
+		ret = -ENOMEM;
+		goto unmap_sync;
+	}
+
+	dma_get_sgtable(subs->dev->bus->sysdev, &xfer_buf_sgt, xfer_buf, xfer_buf_pa,
+			len);
+	va = uaudio_iommu_map(MEM_XFER_BUF, dma_coherent, xfer_buf_pa, len,
+			&xfer_buf_sgt);
+	if (!va) {
+		ret = -ENOMEM;
+		goto unmap_sync;
+	}
+
+	resp->xhci_mem_info.xfer_buff.pa = xfer_buf_pa;
+	resp->xhci_mem_info.xfer_buff.size = len;
+
+	resp->xhci_mem_info.xfer_buff.va = PREPEND_SID_TO_IOVA(va,
+						uaudio_qdev->sid);
+
+	resp->xhci_mem_info_valid = 1;
+
+	sg_free_table(&xfer_buf_sgt);
+
+	if (!atomic_read(&uadev[card_num].in_use)) {
+		kref_init(&uadev[card_num].kref);
+		init_waitqueue_head(&uadev[card_num].disconnect_wq);
+		uadev[card_num].num_intf =
+			subs->dev->config->desc.bNumInterfaces;
+		uadev[card_num].info = kcalloc(uadev[card_num].num_intf,
+			sizeof(struct intf_info), GFP_KERNEL);
+		if (!uadev[card_num].info) {
+			ret = -ENOMEM;
+			goto unmap_sync;
+		}
+		uadev[card_num].udev = subs->dev;
+		atomic_set(&uadev[card_num].in_use, 1);
+	} else {
+		kref_get(&uadev[card_num].kref);
+	}
+
+	uadev[card_num].usb_core_id = resp->controller_num;
+
+	/* cache intf specific info to use it for unmap and free xfer buf */
+	uadev[card_num].info[info_idx].data_xfer_ring_va = tr_data_va;
+	uadev[card_num].info[info_idx].data_xfer_ring_size = PAGE_SIZE;
+	uadev[card_num].info[info_idx].sync_xfer_ring_va = tr_sync_va;
+	uadev[card_num].info[info_idx].sync_xfer_ring_size = PAGE_SIZE;
+	uadev[card_num].info[info_idx].xfer_buf_va = va;
+	uadev[card_num].info[info_idx].xfer_buf_pa = xfer_buf_pa;
+	uadev[card_num].info[info_idx].xfer_buf_size = len;
+	uadev[card_num].info[info_idx].data_ep_pipe = data_ep_pipe;
+	uadev[card_num].info[info_idx].sync_ep_pipe = sync_ep_pipe;
+	uadev[card_num].info[info_idx].xfer_buf = xfer_buf;
+	uadev[card_num].info[info_idx].pcm_card_num = card_num;
+	uadev[card_num].info[info_idx].pcm_dev_num = pcm_dev_num;
+	uadev[card_num].info[info_idx].direction = subs->direction;
+	uadev[card_num].info[info_idx].intf_num = subs->cur_audiofmt->iface;
+	uadev[card_num].info[info_idx].in_use = true;
+
+	set_bit(card_num, &uaudio_qdev->card_slot);
+
+	return 0;
+
+unmap_sync:
+	usb_free_coherent(subs->dev, len, xfer_buf, xfer_buf_pa);
+	uaudio_iommu_unmap(MEM_XFER_RING, tr_sync_va, PAGE_SIZE, PAGE_SIZE);
+unmap_data:
+	uaudio_iommu_unmap(MEM_XFER_RING, tr_data_va, PAGE_SIZE, PAGE_SIZE);
+unmap_er:
+	uaudio_iommu_unmap(MEM_EVENT_RING, IOVA_BASE, PAGE_SIZE, PAGE_SIZE);
+free_sec_ring:
+	xhci_sideband_remove_interrupter(uadev[card_num].sb);
+drop_sync_ep:
+	if (subs->sync_endpoint)
+		xhci_sideband_remove_endpoint(uadev[card_num].sb,
+			usb_pipe_endpoint(subs->dev, subs->sync_endpoint->pipe));
+drop_data_ep:
+	xhci_sideband_remove_endpoint(uadev[card_num].sb,
+			usb_pipe_endpoint(subs->dev, subs->data_endpoint->pipe));
+
+err:
+	return ret;
+}
+
+/**
+ * handle_uaudio_stream_req() - handle stream enable/disable request
+ * @handle: QMI client handle
+ * @sq: qrtr socket
+ * @txn: QMI transaction context
+ * @decoded_msg: decoded QMI message
+ *
+ * Main handler for the QMI stream enable/disable requests.  This executes the
+ * corresponding enable/disable stream apis, respectively.
+ *
+ */
+static void handle_uaudio_stream_req(struct qmi_handle *handle,
+			struct sockaddr_qrtr *sq,
+			struct qmi_txn *txn,
+			const void *decoded_msg)
+{
+	struct qmi_uaudio_stream_req_msg_v01 *req_msg;
+	struct qmi_uaudio_stream_resp_msg_v01 resp = {{0}, 0};
+	struct snd_usb_substream *subs;
+	struct snd_usb_audio *chip = NULL;
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	struct intf_info *info;
+	struct usb_host_endpoint *ep;
+	u8 pcm_card_num, pcm_dev_num, direction;
+	int info_idx = -EINVAL, datainterval = -EINVAL, ret = 0;
+
+	if (!svc->client_connected) {
+		svc->client_sq = *sq;
+		svc->client_connected = true;
+	}
+
+	mutex_lock(&qdev_mutex);
+	req_msg = (struct qmi_uaudio_stream_req_msg_v01 *)decoded_msg;
+	if (!req_msg->audio_format_valid || !req_msg->bit_rate_valid ||
+	    !req_msg->number_of_ch_valid || !req_msg->xfer_buff_size_valid) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	if (!uaudio_qdev) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	direction = (req_msg->usb_token & QMI_STREAM_REQ_DIRECTION);
+	pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
+	pcm_card_num = req_msg->enable ? uaudio_qdev->last_card_num :
+				ffs(uaudio_qdev->card_slot) - 1;
+	if (pcm_card_num >= SNDRV_CARDS) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	if (req_msg->audio_format > USB_QMI_PCM_FORMAT_U32_BE) {
+		ret = -EINVAL;
+		goto response;
+	}
+
+	subs = find_substream(pcm_card_num, pcm_dev_num, direction);
+	chip = uadev[pcm_card_num].chip;
+	if (!subs || !chip || atomic_read(&chip->shutdown)) {
+		ret = -ENODEV;
+		goto response;
+	}
+
+	info_idx = info_idx_from_ifnum(pcm_card_num, subs->cur_audiofmt ?
+			subs->cur_audiofmt->iface : -1, req_msg->enable);
+	if (atomic_read(&chip->shutdown) || !subs->stream || !subs->stream->pcm
+			|| !subs->stream->chip) {
+		ret = -ENODEV;
+		goto response;
+	}
+
+	if (req_msg->enable) {
+		if (info_idx < 0 || chip->system_suspend) {
+			ret = -EBUSY;
+			goto response;
+		}
+	}
+
+	if (req_msg->service_interval_valid) {
+		ret = get_data_interval_from_si(subs,
+						req_msg->service_interval);
+		if (ret == -EINVAL)
+			goto response;
+
+		datainterval = ret;
+	}
+
+	uadev[pcm_card_num].ctrl_intf = chip->ctrl_intf;
+
+	if (req_msg->enable) {
+		ret = enable_audio_stream(subs,
+				map_pcm_format(req_msg->audio_format),
+				req_msg->number_of_ch, req_msg->bit_rate,
+				datainterval);
+
+		if (!ret)
+			ret = prepare_qmi_response(subs, req_msg, &resp,
+					info_idx);
+	} else {
+		info = &uadev[pcm_card_num].info[info_idx];
+		if (info->data_ep_pipe) {
+			ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+						info->data_ep_pipe);
+			if (ep)
+				xhci_sideband_stop_endpoint(uadev[pcm_card_num].sb,
+						ep);
+			xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb, ep);
+			info->data_ep_pipe = 0;
+		}
+
+		if (info->sync_ep_pipe) {
+			ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
+						info->sync_ep_pipe);
+			if (ep)
+				xhci_sideband_stop_endpoint(uadev[pcm_card_num].sb,
+						ep);
+			xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb, ep);
+			info->sync_ep_pipe = 0;
+		}
+
+		disable_audio_stream(subs);
+	}
+
+response:
+	if (!req_msg->enable && ret != -EINVAL && ret != -ENODEV) {
+		mutex_lock(&chip->mutex);
+		if (info_idx >= 0) {
+			info = &uadev[pcm_card_num].info[info_idx];
+			uaudio_dev_intf_cleanup(
+					uadev[pcm_card_num].udev,
+					info);
+		}
+		if (atomic_read(&uadev[pcm_card_num].in_use))
+			kref_put(&uadev[pcm_card_num].kref,
+					uaudio_dev_release);
+		mutex_unlock(&chip->mutex);
+	}
+	mutex_unlock(&qdev_mutex);
+
+	resp.usb_token = req_msg->usb_token;
+	resp.usb_token_valid = 1;
+	resp.internal_status = ret;
+	resp.internal_status_valid = 1;
+	resp.status = ret ? USB_QMI_STREAM_REQ_FAILURE_V01 : ret;
+	resp.status_valid = 1;
+	ret = qmi_send_response(svc->uaudio_svc_hdl, sq, txn,
+			QMI_UAUDIO_STREAM_RESP_V01,
+			QMI_UAUDIO_STREAM_RESP_MSG_V01_MAX_MSG_LEN,
+			qmi_uaudio_stream_resp_msg_v01_ei, &resp);
+}
+
+static struct qmi_msg_handler uaudio_stream_req_handlers = {
+	.type = QMI_REQUEST,
+	.msg_id = QMI_UAUDIO_STREAM_REQ_V01,
+	.ei = qmi_uaudio_stream_req_msg_v01_ei,
+	.decoded_size = QMI_UAUDIO_STREAM_REQ_MSG_V01_MAX_MSG_LEN,
+	.fn = handle_uaudio_stream_req,
+};
+
+/**
+ * qc_usb_audio_offload_init_qmi_dev() - initializes qmi dev
+ *
+ * Initializes the USB qdev, which is used to carry information pertaining to
+ * the offloading resources.  This device is freed only when there are no longer
+ * any offloading candidates. (i.e, when all audio devices are disconnected)
+ *
+ */
+static int qc_usb_audio_offload_init_qmi_dev(struct usb_device *udev)
+{
+	uaudio_qdev = kzalloc(sizeof(struct uaudio_qmi_dev),
+		GFP_KERNEL);
+	if (!uaudio_qdev)
+		return -ENOMEM;
+
+	/* initialize xfer ring and xfer buf iova list */
+	INIT_LIST_HEAD(&uaudio_qdev->xfer_ring_list);
+	uaudio_qdev->curr_xfer_ring_iova = IOVA_XFER_RING_BASE;
+	uaudio_qdev->xfer_ring_iova_size =
+			IOVA_XFER_RING_MAX - IOVA_XFER_RING_BASE;
+
+	INIT_LIST_HEAD(&uaudio_qdev->xfer_buf_list);
+	uaudio_qdev->curr_xfer_buf_iova = IOVA_XFER_BUF_BASE;
+	uaudio_qdev->xfer_buf_iova_size =
+		IOVA_XFER_BUF_MAX - IOVA_XFER_BUF_BASE;
+
+	return 0;
+}
+
+/**
+ * qc_usb_audio_offload_probe() - platform op connect handler
+ * @chip: USB SND device
+ *
+ * Platform connect handler when a USB SND device is detected. Will
+ * notify SOC USB about the connection to enable the USB ASoC backend
+ * and populate internal USB chip array.
+ *
+ */
+static void qc_usb_audio_offload_probe(struct snd_usb_audio *chip)
+{
+	struct usb_device *udev = chip->dev;
+	struct xhci_sideband *sb;
+	struct snd_soc_usb_device *sdev;
+
+	/*
+	 * If there is no priv_data, the connected device is on a USB bus
+	 * that doesn't support offloading.  Avoid populating entries for
+	 * this device.
+	 */
+	if (!snd_soc_usb_find_priv_data(usb_get_usb_backend(udev)))
+		return;
+
+	mutex_lock(&chip->mutex);
+	if (!uadev[chip->card->number].chip) {
+		sdev = kzalloc(sizeof(*sdev), GFP_KERNEL);
+		if (!sdev)
+			goto exit;
+
+		sb = xhci_sideband_register(udev);
+		if (!sb)
+			goto free_sdev;
+	} else {
+		sb = uadev[chip->card->number].sb;
+		sdev = uadev[chip->card->number].sdev;
+	}
+
+	mutex_lock(&qdev_mutex);
+	if (!uaudio_qdev)
+		qc_usb_audio_offload_init_qmi_dev(udev);
+
+	atomic_inc(&uaudio_qdev->qdev_in_use);
+	mutex_unlock(&qdev_mutex);
+
+	uadev[chip->card->number].sb = sb;
+	uadev[chip->card->number].chip = chip;
+
+	sdev->card_idx = chip->card->number;
+	sdev->chip_idx = chip->index;
+	uadev[chip->card->number].sdev = sdev;
+
+	uaudio_qdev->last_card_num = chip->card->number;
+	snd_soc_usb_connect(usb_get_usb_backend(udev), sdev);
+	mutex_unlock(&chip->mutex);
+
+	return;
+
+free_sdev:
+	kfree(sdev);
+exit:
+	mutex_unlock(&chip->mutex);
+}
+
+/**
+ * qc_usb_audio_cleanup_qmi_dev() - release qmi device
+ *
+ * Frees the USB qdev.  Only occurs when there are no longer any potential
+ * devices that can utilize USB audio offloading.
+ *
+ */
+static void qc_usb_audio_cleanup_qmi_dev(void)
+{
+	kfree(uaudio_qdev);
+	uaudio_qdev = NULL;
+}
+
+/**
+ * qc_usb_audio_offload_disconnect() - platform op disconnect handler
+ * @chip: USB SND device
+ *
+ * Platform disconnect handler.  Will ensure that any pending stream is
+ * halted by issuing a QMI disconnect indication packet to the adsp.
+ *
+ */
+static void qc_usb_audio_offload_disconnect(struct snd_usb_audio *chip)
+{
+	struct qmi_uaudio_stream_ind_msg_v01 disconnect_ind = {0};
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	struct uaudio_dev *dev;
+	int card_num;
+	int ret;
+
+	if (!chip)
+		return;
+
+	card_num = chip->card->number;
+	if (card_num >= SNDRV_CARDS)
+		return;
+
+	mutex_lock(&qdev_mutex);
+	mutex_lock(&chip->mutex);
+	dev = &uadev[card_num];
+
+	/* Device has already been cleaned up, or never populated */
+	if (!dev->chip) {
+		mutex_unlock(&qdev_mutex);
+		mutex_unlock(&chip->mutex);
+		return;
+	}
+
+	/* clean up */
+	if (!dev->udev)
+		goto done;
+
+	if (atomic_read(&dev->in_use)) {
+		mutex_unlock(&chip->mutex);
+		mutex_unlock(&qdev_mutex);
+		dev_dbg(uaudio_qdev->dev, "sending qmi indication disconnect\n");
+		disconnect_ind.dev_event = USB_QMI_DEV_DISCONNECT_V01;
+		disconnect_ind.slot_id = dev->udev->slot_id;
+		disconnect_ind.controller_num = dev->usb_core_id;
+		disconnect_ind.controller_num_valid = 1;
+		ret = qmi_send_indication(svc->uaudio_svc_hdl, &svc->client_sq,
+				QMI_UAUDIO_STREAM_IND_V01,
+				QMI_UAUDIO_STREAM_IND_MSG_V01_MAX_MSG_LEN,
+				qmi_uaudio_stream_ind_msg_v01_ei,
+				&disconnect_ind);
+		if (ret < 0)
+			dev_err(uaudio_qdev->dev,
+				"qmi send failed with err: %d\n", ret);
+
+		ret = wait_event_interruptible_timeout(dev->disconnect_wq,
+				!atomic_read(&dev->in_use),
+				msecs_to_jiffies(DEV_RELEASE_WAIT_TIMEOUT));
+		if (!ret) {
+			dev_err(uaudio_qdev->dev,
+				"timeout while waiting for dev_release\n");
+			atomic_set(&dev->in_use, 0);
+		} else if (ret < 0) {
+			dev_err(uaudio_qdev->dev, "failed with ret %d\n", ret);
+			atomic_set(&dev->in_use, 0);
+		}
+		mutex_lock(&qdev_mutex);
+		mutex_lock(&chip->mutex);
+	}
+
+	uaudio_dev_cleanup(dev);
+done:
+	snd_soc_usb_disconnect(usb_get_usb_backend(chip->dev), dev->sdev);
+
+	/*
+	 * If num_interfaces == 1, the last USB SND interface is being removed.
+	 * This is to accommodate for devices w/ multiple UAC functions.
+	 */
+	if (chip->num_interfaces == 1) {
+		xhci_sideband_unregister(dev->sb);
+		dev->chip = NULL;
+		kfree(dev->sdev);
+		dev->sdev = NULL;
+	}
+	mutex_unlock(&chip->mutex);
+
+	atomic_dec(&uaudio_qdev->qdev_in_use);
+	if (!atomic_read(&uaudio_qdev->qdev_in_use)) {
+		snd_soc_usb_disconnect(usb_get_usb_backend(udev));
+		qc_usb_audio_cleanup_qmi_dev();
+	}
+	mutex_unlock(&qdev_mutex);
+}
+
+/**
+ * qc_usb_audio_offload_suspend() - USB offload PM suspend handler
+ * @intf: USB interface
+ * @message: suspend type
+ *
+ * PM suspend handler to ensure that the USB offloading driver is able to stop
+ * any pending traffic, so that the bus can be suspended.
+ *
+ */
+static void qc_usb_audio_offload_suspend(struct usb_interface *intf, pm_message_t message)
+{
+	struct snd_usb_audio *chip = usb_get_intfdata(intf);
+	struct qmi_uaudio_stream_ind_msg_v01 disconnect_ind = {0};
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	struct uaudio_dev *dev;
+	int card_num;
+	int ret;
+
+	if (!chip)
+		return;
+
+	card_num = chip->card->number;
+	if (card_num >= SNDRV_CARDS)
+		return;
+
+
+	mutex_lock(&chip->mutex);
+	dev = &uadev[card_num];
+
+	if (atomic_read(&dev->in_use)) {
+		mutex_unlock(&chip->mutex);
+		dev_dbg(uaudio_qdev->dev, "sending qmi indication suspend\n");
+		disconnect_ind.dev_event = USB_QMI_DEV_DISCONNECT_V01;
+		disconnect_ind.slot_id = dev->udev->slot_id;
+		disconnect_ind.controller_num = dev->usb_core_id;
+		disconnect_ind.controller_num_valid = 1;
+		ret = qmi_send_indication(svc->uaudio_svc_hdl, &svc->client_sq,
+				QMI_UAUDIO_STREAM_IND_V01,
+				QMI_UAUDIO_STREAM_IND_MSG_V01_MAX_MSG_LEN,
+				qmi_uaudio_stream_ind_msg_v01_ei,
+				&disconnect_ind);
+		if (ret < 0)
+			dev_err(uaudio_qdev->dev,
+				"qmi send failed with err: %d\n", ret);
+
+		ret = wait_event_interruptible_timeout(dev->disconnect_wq,
+				!atomic_read(&dev->in_use),
+				msecs_to_jiffies(DEV_RELEASE_WAIT_TIMEOUT));
+		if (!ret) {
+			dev_err(uaudio_qdev->dev,
+				"timeout while waiting for dev_release\n");
+			atomic_set(&dev->in_use, 0);
+		} else if (ret < 0) {
+			dev_err(uaudio_qdev->dev, "failed with ret %d\n", ret);
+			atomic_set(&dev->in_use, 0);
+		}
+		mutex_lock(&chip->mutex);
+	}
+	mutex_unlock(&chip->mutex);
+}
+
+static struct snd_usb_platform_ops offload_ops = {
+	.connect_cb = qc_usb_audio_offload_probe,
+	.disconnect_cb = qc_usb_audio_offload_disconnect,
+	.suspend_cb = qc_usb_audio_offload_suspend,
+};
+
+static int __init qc_usb_audio_offload_init(void)
+{
+	struct uaudio_qmi_svc *svc;
+	int ret;
+
+	svc = kzalloc(sizeof(struct uaudio_qmi_svc), GFP_KERNEL);
+	if (!svc)
+		return -ENOMEM;
+
+	svc->uaudio_wq = create_singlethread_workqueue("uaudio_svc");
+	if (!svc->uaudio_wq) {
+		ret = -ENOMEM;
+		goto free_svc;
+	}
+
+	svc->uaudio_svc_hdl = kzalloc(sizeof(struct qmi_handle), GFP_KERNEL);
+	if (!svc->uaudio_svc_hdl) {
+		ret = -ENOMEM;
+		goto free_wq;
+	}
+
+	ret = qmi_handle_init(svc->uaudio_svc_hdl,
+				QMI_UAUDIO_STREAM_REQ_MSG_V01_MAX_MSG_LEN,
+				&uaudio_svc_ops_options,
+				&uaudio_stream_req_handlers);
+	ret = qmi_add_server(svc->uaudio_svc_hdl, UAUDIO_STREAM_SERVICE_ID_V01,
+					UAUDIO_STREAM_SERVICE_VERS_V01, 0);
+
+	INIT_WORK(&svc->qmi_disconnect_work, qmi_disconnect_work);
+	uaudio_svc = svc;
+
+	ret = snd_usb_register_platform_ops(&offload_ops);
+	if (ret < 0)
+		goto release_qmi;
+
+	return 0;
+
+release_qmi:
+	qmi_handle_release(svc->uaudio_svc_hdl);
+free_wq:
+	destroy_workqueue(svc->uaudio_wq);
+free_svc:
+	kfree(svc);
+
+	return ret;
+}
+
+static void __exit qc_usb_audio_offload_exit(void)
+{
+	struct uaudio_qmi_svc *svc = uaudio_svc;
+	int idx;
+
+	/*
+	 * Remove all connected devices after unregistering ops, to ensure
+	 * that no further connect events will occur.  The disconnect routine
+	 * will issue the QMI disconnect indication, which results in the
+	 * external DSP to stop issuing transfers.
+	 */
+	snd_usb_unregister_platform_ops();
+	for (idx = 0; idx < SNDRV_CARDS; idx++)
+		qc_usb_audio_offload_disconnect(uadev[idx].chip);
+
+	qmi_handle_release(svc->uaudio_svc_hdl);
+	flush_workqueue(svc->uaudio_wq);
+	destroy_workqueue(svc->uaudio_wq);
+	kfree(svc);
+	uaudio_svc = NULL;
+}
+
+module_init(qc_usb_audio_offload_init);
+module_exit(qc_usb_audio_offload_exit);
+
+MODULE_DESCRIPTION("QC USB Audio Offloading");
+MODULE_LICENSE("GPL");