// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
 */

#include <linux/auxiliary_bus.h>
#include <linux/ctype.h>
#include <linux/dma-mapping.h>
#include <linux/dma-map-ops.h>
#include <linux/init.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/soc/qcom/qmi.h>
#include <linux/usb.h>
#include <linux/usb/audio.h>
#include <linux/usb/audio-v2.h>
#include <linux/usb/audio-v3.h>
#include <linux/usb/hcd.h>
#include <linux/usb/quirks.h>
#include <linux/usb/xhci-sideband.h>

#include <sound/control.h>
#include <sound/core.h>
#include <sound/info.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/q6usboffload.h>
#include <sound/soc.h>
#include <sound/soc-usb.h>

#include "../usbaudio.h"
#include "../card.h"
#include "../endpoint.h"
#include "../format.h"
#include "../helper.h"
#include "../pcm.h"
#include "../power.h"

#include "mixer_usb_offload.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_MASK(iova) (((u64)(iova)) & 0xFFFFFFFF)
#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 {
        /* IOMMU ring/buffer mapping information */
        unsigned long data_xfer_ring_va;
        size_t data_xfer_ring_size;
        unsigned long sync_xfer_ring_va;
        size_t sync_xfer_ring_size;
        dma_addr_t xfer_buf_iova;
        size_t xfer_buf_size;
        dma_addr_t xfer_buf_dma;
        u8 *xfer_buf_cpu;

        /* USB endpoint information */
        unsigned int data_ep_pipe;
        unsigned int sync_ep_pipe;
        unsigned int data_ep_idx;
        unsigned int sync_ep_idx;

        u8 intf_num;
        u8 pcm_card_num;
        u8 pcm_dev_num;
        u8 direction;
        bool in_use;
};

struct uaudio_qmi_dev {
        struct device *dev;
        struct q6usb_offload *data;
        struct auxiliary_device *auxdev;

        /* 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;
};

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 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 int usb_qmi_get_pcm_num(struct snd_usb_audio *chip, int direction)
{
        struct snd_usb_substream *subs = NULL;
        struct snd_usb_stream *as;
        int count = 0;

        list_for_each_entry(as, &chip->pcm_list, list) {
                subs = &as->substream[direction];
                if (subs->ep_num)
                        count++;
        }

        return count;
}

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_substream *subs = NULL;
        struct snd_usb_audio *chip;
        struct snd_usb_stream *as;

        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_mult;
        unsigned int bus_intval;
        unsigned int 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;
        }
}

/*
 * Sends QMI disconnect indication message, assumes chip->mutex and qdev_mutex
 * lock held by caller.
 */
static int uaudio_send_disconnect_ind(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 ret = 0;

        dev = &uadev[chip->card->number];

        if (atomic_read(&dev->in_use)) {
                mutex_unlock(&chip->mutex);
                mutex_unlock(&qdev_mutex);
                dev_dbg(uaudio_qdev->data->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->data->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->data->dev,
                                "timeout while waiting for dev_release\n");
                        atomic_set(&dev->in_use, 0);
                } else if (ret < 0) {
                        dev_err(uaudio_qdev->data->dev,
                                "failed with ret %d\n", ret);
                        atomic_set(&dev->in_use, 0);
                }
                mutex_lock(&qdev_mutex);
                mutex_lock(&chip->mutex);
        }

        return ret;
}

/* 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;
        size_t tmp_size = size;
        unsigned long iova = 0;

        if (size % PAGE_SIZE)
                goto done;

        if (size > *curr_iova_size)
                goto done;

        if (*curr_iova_size == 0)
                goto done;

        list_for_each_entry(info, head, list) {
                /* exact size iova_info */
                if (!info->in_use && info->size == size) {
                        info->in_use = true;
                        iova = info->start_iova;
                        *curr_iova_size -= size;
                        goto done;
                } else if (!info->in_use && tmp_size >= info->size) {
                        if (!new_info)
                                new_info = info;
                        tmp_size -= info->size;
                        if (tmp_size)
                                continue;

                        iova = 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;
                        goto done;
                } else {
                        /* iova region in use */
                        new_info = NULL;
                        tmp_size = size;
                }
        }

        info = kzalloc_obj(*info);
        if (!info) {
                iova = 0;
                goto done;
        }

        iova = *curr_iova;
        info->start_iova = *curr_iova;
        info->size = size;
        info->in_use = true;
        *curr_iova += size;
        *curr_iova_size -= size;
        list_add_tail(&info->list, head);

done:
        return iova;
}

static void uaudio_put_iova(unsigned long iova, 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 == iova) {
                        if (!info->in_use)
                                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)
                return;

done:
        *curr_iova_size += size;
}

/**
 * uaudio_iommu_unmap() - unmaps iommu memory for adsp
 * @mtype: ring type
 * @iova: 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 iova,
                               size_t iova_size, size_t mapped_iova_size)
{
        size_t umap_size;
        bool unmap = true;

        if (!iova || !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(iova, iova_size, &uaudio_qdev->xfer_ring_list,
                                &uaudio_qdev->xfer_ring_iova_size);
                break;
        case MEM_XFER_BUF:
                uaudio_put_iova(iova, iova_size, &uaudio_qdev->xfer_buf_list,
                                &uaudio_qdev->xfer_buf_iova_size);
                break;
        default:
                unmap = false;
        }

        if (!unmap || !mapped_iova_size)
                return;

        umap_size = iommu_unmap(uaudio_qdev->data->domain, iova, mapped_iova_size);
        if (umap_size != mapped_iova_size)
                dev_err(uaudio_qdev->data->dev,
                        "unmapped size %zu for iova 0x%08lx of mapped size %zu\n",
                        umap_size, iova, mapped_iova_size);
}

static int uaudio_iommu_map_prot(bool dma_coherent)
{
        int prot = IOMMU_READ | IOMMU_WRITE;

        if (dma_coherent)
                prot |= IOMMU_CACHE;
        return prot;
}

/**
 * uaudio_iommu_map_pa() - maps iommu memory for adsp
 * @mtype: ring type
 * @dma_coherent: dma coherent
 * @pa: physical address for ring/buffer
 * @size: size of 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_pa(enum mem_type mtype, bool dma_coherent,
                                         phys_addr_t pa, size_t size)
{
        unsigned long iova = 0;
        bool map = true;
        int prot = uaudio_iommu_map_prot(dma_coherent);

        switch (mtype) {
        case MEM_EVENT_RING:
                iova = IOVA_BASE;
                /* er already mapped */
                if (uaudio_qdev->er_mapped)
                        map = false;
                break;
        case MEM_XFER_RING:
                iova = uaudio_get_iova(&uaudio_qdev->curr_xfer_ring_iova,
                                     &uaudio_qdev->xfer_ring_iova_size,
                                     &uaudio_qdev->xfer_ring_list, size);
                break;
        default:
                dev_err(uaudio_qdev->data->dev, "unknown mem type %d\n", mtype);
        }

        if (!iova || !map)
                return 0;

        iommu_map(uaudio_qdev->data->domain, iova, pa, size, prot, GFP_KERNEL);

        return iova;
}

static unsigned long uaudio_iommu_map_xfer_buf(bool dma_coherent, size_t size,
                                               struct sg_table *sgt)
{
        struct scatterlist *sg;
        unsigned long iova = 0;
        size_t total_len = 0;
        unsigned long iova_sg;
        phys_addr_t pa_sg;
        size_t sg_len;
        int prot = uaudio_iommu_map_prot(dma_coherent);
        int ret;
        int i;

        prot = IOMMU_READ | IOMMU_WRITE;

        if (dma_coherent)
                prot |= IOMMU_CACHE;

        iova = uaudio_get_iova(&uaudio_qdev->curr_xfer_buf_iova,
                               &uaudio_qdev->xfer_buf_iova_size,
                               &uaudio_qdev->xfer_buf_list, size);
        if (!iova)
                goto done;

        iova_sg = iova;
        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->data->domain, iova_sg, pa_sg, sg_len,
                                prot, GFP_KERNEL);
                if (ret) {
                        uaudio_iommu_unmap(MEM_XFER_BUF, iova, size, total_len);
                        iova = 0;
                        goto done;
                }

                iova_sg += sg_len;
                total_len += sg_len;
        }

        if (size != total_len) {
                uaudio_iommu_unmap(MEM_XFER_BUF, iova, size, total_len);
                iova = 0;
        }
done:
        return iova;
}

/* 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_iova, info->xfer_buf_size,
                           info->xfer_buf_size);
        info->xfer_buf_iova = 0;

        usb_free_coherent(udev, info->xfer_buf_size, info->xfer_buf_cpu,
                          info->xfer_buf_dma);
        info->xfer_buf_size = 0;
        info->xfer_buf_cpu = NULL;
        info->xfer_buf_dma = 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);
                usb_offload_put(dev->udev);
        }
}

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->data->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_stop_session(void)
{
        struct snd_usb_substream *subs;
        struct usb_host_endpoint *ep;
        struct snd_usb_audio *chip;
        struct intf_info *info;
        int pcm_card_num;
        int if_idx;
        int idx;

        guard(mutex)(&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];
                        pcm_card_num = info->pcm_card_num;
                        subs = find_substream(pcm_card_num, info->pcm_dev_num,
                                              info->direction);
                        if (!subs || !chip || atomic_read(&chip->shutdown)) {
                                dev_err(&uadev[idx].udev->dev,
                                        "no sub for c#%u dev#%u dir%u\n",
                                        info->pcm_card_num,
                                        info->pcm_dev_num,
                                        info->direction);
                                continue;
                        }
                        /* Release XHCI endpoints */
                        if (info->data_ep_pipe)
                                ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
                                                       info->data_ep_pipe);
                        xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb, ep);

                        if (info->sync_ep_pipe)
                                ep = usb_pipe_endpoint(uadev[pcm_card_num].udev,
                                                       info->sync_ep_pipe);
                        xhci_sideband_remove_endpoint(uadev[pcm_card_num].sb, ep);

                        disable_audio_stream(subs);
                }
                atomic_set(&uadev[idx].in_use, 0);
                guard(mutex)(&chip->mutex);
                uaudio_dev_cleanup(&uadev[idx]);
        }
}

/**
 * uaudio_sideband_notifier() - xHCI sideband event handler
 * @intf: USB interface handle
 * @evt: xHCI sideband event type
 *
 * This callback is executed when the xHCI sideband encounters a sequence
 * that requires the sideband clients to take action.  An example, is when
 * xHCI frees the transfer ring, so the client has to ensure that the
 * offload path is halted.
 *
 */
static int uaudio_sideband_notifier(struct usb_interface *intf,
                                    struct xhci_sideband_event *evt)
{
        struct snd_usb_audio *chip;
        struct uaudio_dev *dev;
        int if_idx;

        if (!intf || !evt)
                return 0;

        chip = usb_get_intfdata(intf);

        guard(mutex)(&qdev_mutex);
        guard(mutex)(&chip->mutex);

        dev = &uadev[chip->card->number];

        if (evt->type == XHCI_SIDEBAND_XFER_RING_FREE) {
                unsigned int *ep = (unsigned int *) evt->evt_data;

                for (if_idx = 0; if_idx < dev->num_intf; if_idx++) {
                        if (dev->info[if_idx].data_ep_idx == *ep ||
                            dev->info[if_idx].sync_ep_idx == *ep)
                                uaudio_send_disconnect_ind(chip);
                }
        }

        return 0;
}

/**
 * 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) {
                qmi_stop_session();

                /* clear QMI client parameters to block further QMI messages */
                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)
                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) {
                qmi_stop_session();

                /* clear QMI client parameters to block further QMI messages */
                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_pcm_hw_params params;
        struct snd_usb_audio *chip;
        struct snd_interval *i;
        struct snd_mask *m;
        int ret;

        chip = subs->stream->chip;

        _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 = channels;
        i->max = channels;

        i = hw_param_interval(&params, SNDRV_PCM_HW_PARAM_RATE);
        snd_interval_setinteger(i);
        i->min = cur_rate;
        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)) {
                CLASS(snd_usb_lock, pm)(chip);
                if (pm.err < 0) {
                        ret = pm.err;
                        goto detach_ep;
                }

                if (subs->sync_endpoint) {
                        ret = snd_usb_endpoint_prepare(chip, subs->sync_endpoint);
                        if (ret < 0)
                                goto detach_ep;
                }

                ret = snd_usb_endpoint_prepare(chip, subs->data_endpoint);
                if (ret < 0)
                        goto detach_ep;

                dev_dbg(uaudio_qdev->data->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;

detach_ep:
        snd_usb_hw_free(subs);

put_suspend:
        snd_usb_autosuspend(chip);

        return ret;
}

/**
 * uaudio_transfer_buffer_setup() - fetch and populate xfer buffer params
 * @subs: usb substream
 * @xfer_buf_cpu: xfer buf to be allocated
 * @xfer_buf_len: size of allocation
 * @mem_info: QMI response info
 *
 * Allocates and maps the transfer buffers that will be utilized by the
 * audio DSP.  Will populate the information in the QMI response that is
 * sent back to the stream enable request.
 *
 */
static int uaudio_transfer_buffer_setup(struct snd_usb_substream *subs,
                                        void **xfer_buf_cpu, u32 xfer_buf_len,
                                        struct mem_info_v01 *mem_info)
{
        struct sg_table xfer_buf_sgt;
        dma_addr_t xfer_buf_dma;
        void *xfer_buf;
        u32 len = xfer_buf_len;
        bool dma_coherent;
        dma_addr_t xfer_buf_dma_sysdev;
        u32 remainder;
        u32 mult;
        int ret;

        dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);

        /* xfer buffer, multiple of 4K only */
        if (!len)
                len = PAGE_SIZE;

        mult = len / PAGE_SIZE;
        remainder = len % PAGE_SIZE;
        len = mult * PAGE_SIZE;
        len += remainder ? PAGE_SIZE : 0;

        if (len > MAX_XFER_BUFF_LEN) {
                dev_err(uaudio_qdev->data->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;
        }

        /* get buffer mapped into subs->dev */
        xfer_buf = usb_alloc_coherent(subs->dev, len, GFP_KERNEL, &xfer_buf_dma);
        if (!xfer_buf)
                return -ENOMEM;

        dma_get_sgtable(subs->dev->bus->sysdev, &xfer_buf_sgt, xfer_buf,
                        xfer_buf_dma, len);

        /* map the physical buffer into sysdev as well */
        xfer_buf_dma_sysdev = uaudio_iommu_map_xfer_buf(dma_coherent,
                                                        len, &xfer_buf_sgt);
        if (!xfer_buf_dma_sysdev) {
                ret = -ENOMEM;
                goto unmap_sync;
        }

        mem_info->dma = xfer_buf_dma;
        mem_info->size = len;
        mem_info->iova = PREPEND_SID_TO_IOVA(xfer_buf_dma_sysdev, uaudio_qdev->data->sid);
        *xfer_buf_cpu = xfer_buf;
        sg_free_table(&xfer_buf_sgt);

        return 0;

unmap_sync:
        usb_free_coherent(subs->dev, len, xfer_buf, xfer_buf_dma);

        return ret;
}

/**
 * uaudio_endpoint_setup() - fetch and populate endpoint params
 * @subs: usb substream
 * @endpoint: usb endpoint to add
 * @card_num: uadev index
 * @mem_info: QMI response info
 * @ep_desc: QMI ep desc response field
 *
 * Initialize the USB endpoint being used for a particular USB
 * stream.  Will request XHCI sec intr to reserve the EP for
 * offloading as well as populating the QMI response with the
 * transfer ring parameters.
 *
 */
static phys_addr_t
uaudio_endpoint_setup(struct snd_usb_substream *subs,
                      struct snd_usb_endpoint *endpoint, int card_num,
                      struct mem_info_v01 *mem_info,
                      struct usb_endpoint_descriptor_v01 *ep_desc)
{
        struct usb_host_endpoint *ep;
        phys_addr_t tr_pa = 0;
        struct sg_table *sgt;
        bool dma_coherent;
        unsigned long iova;
        struct page *pg;
        int ret = -ENODEV;

        dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);

        ep = usb_pipe_endpoint(subs->dev, endpoint->pipe);
        if (!ep) {
                dev_err(uaudio_qdev->data->dev, "data ep # %d context is null\n",
                        subs->data_endpoint->ep_num);
                goto exit;
        }

        memcpy(ep_desc, &ep->desc, sizeof(ep->desc));

        ret = xhci_sideband_add_endpoint(uadev[card_num].sb, ep);
        if (ret < 0) {
                dev_err(&subs->dev->dev,
                        "failed to add data ep to sec intr\n");
                ret = -ENODEV;
                goto exit;
        }

        sgt = xhci_sideband_get_endpoint_buffer(uadev[card_num].sb, ep);
        if (!sgt) {
                dev_err(&subs->dev->dev,
                        "failed to get data ep ring address\n");
                ret = -ENODEV;
                goto remove_ep;
        }

        pg = sg_page(sgt->sgl);
        tr_pa = page_to_phys(pg);
        mem_info->dma = sg_dma_address(sgt->sgl);
        sg_free_table(sgt);

        /* data transfer ring */
        iova = uaudio_iommu_map_pa(MEM_XFER_RING, dma_coherent, tr_pa,
                                   PAGE_SIZE);
        if (!iova) {
                ret = -ENOMEM;
                goto clear_pa;
        }

        mem_info->iova = PREPEND_SID_TO_IOVA(iova, uaudio_qdev->data->sid);
        mem_info->size = PAGE_SIZE;

        return 0;

clear_pa:
        mem_info->dma = 0;
remove_ep:
        xhci_sideband_remove_endpoint(uadev[card_num].sb, ep);
exit:
        return ret;
}

/**
 * uaudio_event_ring_setup() - fetch and populate event ring params
 * @subs: usb substream
 * @card_num: uadev index
 * @mem_info: QMI response info
 *
 * Register secondary interrupter to XHCI and fetch the event buffer info
 * and populate the information into the QMI response.
 *
 */
static int uaudio_event_ring_setup(struct snd_usb_substream *subs,
                                   int card_num, struct mem_info_v01 *mem_info)
{
        struct sg_table *sgt;
        phys_addr_t er_pa;
        bool dma_coherent;
        unsigned long iova;
        struct page *pg;
        int ret;

        dma_coherent = dev_is_dma_coherent(subs->dev->bus->sysdev);
        er_pa = 0;

        ret = usb_offload_get(subs->dev);
        if (ret < 0)
                goto exit;

        /* event ring */
        ret = xhci_sideband_create_interrupter(uadev[card_num].sb, 1, false,
                                               0, uaudio_qdev->data->intr_num);
        if (ret < 0) {
                dev_err(&subs->dev->dev, "failed to fetch interrupter\n");
                goto put_offload;
        }

        sgt = xhci_sideband_get_event_buffer(uadev[card_num].sb);
        if (!sgt) {
                dev_err(&subs->dev->dev,
                        "failed to get event ring address\n");
                ret = -ENODEV;
                goto remove_interrupter;
        }

        pg = sg_page(sgt->sgl);
        er_pa = page_to_phys(pg);
        mem_info->dma = sg_dma_address(sgt->sgl);
        sg_free_table(sgt);

        iova = uaudio_iommu_map_pa(MEM_EVENT_RING, dma_coherent, er_pa,
                                   PAGE_SIZE);
        if (!iova) {
                ret = -ENOMEM;
                goto clear_pa;
        }

        mem_info->iova = PREPEND_SID_TO_IOVA(iova, uaudio_qdev->data->sid);
        mem_info->size = PAGE_SIZE;

        return 0;

clear_pa:
        mem_info->dma = 0;
remove_interrupter:
        xhci_sideband_remove_interrupter(uadev[card_num].sb);
put_offload:
        usb_offload_put(subs->dev);
exit:
        return ret;
}

/**
 * uaudio_populate_uac_desc() - parse UAC parameters and populate QMI resp
 * @subs: usb substream
 * @resp: QMI response buffer
 *
 * Parses information specified within UAC descriptors which explain the
 * sample parameters that the device expects.  This information is populated
 * to the QMI response sent back to the audio DSP.
 *
 */
static int uaudio_populate_uac_desc(struct snd_usb_substream *subs,
                                    struct qmi_uaudio_stream_resp_msg_v01 *resp)
{
        struct usb_interface_descriptor *altsd;
        struct usb_host_interface *alts;
        struct usb_interface *iface;
        int protocol;

        iface = usb_ifnum_to_if(subs->dev, subs->cur_audiofmt->iface);
        if (!iface) {
                dev_err(&subs->dev->dev, "interface # %d does not exist\n",
                        subs->cur_audiofmt->iface);
                return -ENODEV;
        }

        alts = &iface->altsetting[subs->cur_audiofmt->altset_idx];
        altsd = get_iface_desc(alts);
        protocol = altsd->bInterfaceProtocol;

        if (protocol == UAC_VERSION_1) {
                struct uac1_as_header_descriptor *as;

                as = snd_usb_find_csint_desc(alts->extra, alts->extralen, NULL,
                                             UAC_AS_GENERAL);
                if (!as) {
                        dev_err(&subs->dev->dev,
                                "%u:%d : no UAC_AS_GENERAL desc\n",
                                subs->cur_audiofmt->iface,
                                subs->cur_audiofmt->altset_idx);
                        return -ENODEV;
                }

                resp->data_path_delay = as->bDelay;
                resp->data_path_delay_valid = 1;

                resp->usb_audio_subslot_size = subs->cur_audiofmt->fmt_sz;
                resp->usb_audio_subslot_size_valid = 1;

                resp->usb_audio_spec_revision = le16_to_cpu((__force __le16)0x0100);
                resp->usb_audio_spec_revision_valid = 1;
        } else if (protocol == UAC_VERSION_2) {
                resp->usb_audio_subslot_size = subs->cur_audiofmt->fmt_sz;
                resp->usb_audio_subslot_size_valid = 1;

                resp->usb_audio_spec_revision = le16_to_cpu((__force __le16)0x0200);
                resp->usb_audio_spec_revision_valid = 1;
        } else if (protocol == UAC_VERSION_3) {
                if (iface->intf_assoc->bFunctionSubClass ==
                                        UAC3_FUNCTION_SUBCLASS_FULL_ADC_3_0) {
                        dev_err(&subs->dev->dev,
                                "full adc is not supported\n");
                        return -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(&subs->dev->dev,
                                "%d: %u: Invalid wMaxPacketSize\n",
                                subs->cur_audiofmt->iface,
                                subs->cur_audiofmt->altset_idx);
                        return -EINVAL;
                }
                resp->usb_audio_subslot_size_valid = 1;
        } else {
                dev_err(&subs->dev->dev, "unknown protocol version %x\n",
                        protocol);
                return -ENODEV;
        }

        memcpy(&resp->std_as_opr_intf_desc, &alts->desc, sizeof(alts->desc));

        return 0;
}

/**
 * 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 q6usb_offload *data;
        int pcm_dev_num;
        int card_num;
        void *xfer_buf_cpu;
        int ret;

        pcm_dev_num = (req_msg->usb_token & QMI_STREAM_REQ_DEV_NUM_MASK) >> 8;
        card_num = (req_msg->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;

        if (!uadev[card_num].ctrl_intf) {
                dev_err(&subs->dev->dev, "audio ctrl intf info not cached\n");
                return -ENODEV;
        }

        ret = uaudio_populate_uac_desc(subs, resp);
        if (ret < 0)
                return ret;

        resp->slot_id = subs->dev->slot_id;
        resp->slot_id_valid = 1;

        data = snd_soc_usb_find_priv_data(uaudio_qdev->auxdev->dev.parent);
        if (!data) {
                dev_err(&subs->dev->dev, "No private data found\n");
                return -ENODEV;
        }

        uaudio_qdev->data = data;

        resp->std_as_opr_intf_desc_valid = 1;
        ret = uaudio_endpoint_setup(subs, subs->data_endpoint, card_num,
                                    &resp->xhci_mem_info.tr_data,
                                    &resp->std_as_data_ep_desc);
        if (ret < 0)
                return ret;

        resp->std_as_data_ep_desc_valid = 1;

        if (subs->sync_endpoint) {
                ret = uaudio_endpoint_setup(subs, subs->sync_endpoint, card_num,
                                            &resp->xhci_mem_info.tr_sync,
                                            &resp->std_as_sync_ep_desc);
                if (ret < 0)
                        goto drop_data_ep;

                resp->std_as_sync_ep_desc_valid = 1;
        }

        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;
        }

        /* event ring */
        ret = uaudio_event_ring_setup(subs, card_num,
                                      &resp->xhci_mem_info.evt_ring);
        if (ret < 0)
                goto drop_sync_ep;

        uaudio_qdev->er_mapped = true;
        resp->interrupter_num = xhci_sideband_interrupter_id(uadev[card_num].sb);

        resp->speed_info = get_speed_info(subs->dev->speed);
        if (resp->speed_info == USB_QMI_DEVICE_SPEED_INVALID_V01) {
                ret = -ENODEV;
                goto free_sec_ring;
        }

        resp->speed_info_valid = 1;

        ret = uaudio_transfer_buffer_setup(subs, &xfer_buf_cpu, req_msg->xfer_buff_size,
                                           &resp->xhci_mem_info.xfer_buff);
        if (ret < 0) {
                ret = -ENOMEM;
                goto free_sec_ring;
        }

        resp->xhci_mem_info_valid = 1;

        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 = kzalloc_objs(struct intf_info,
                                                    uadev[card_num].num_intf);
                if (!uadev[card_num].info) {
                        ret = -ENOMEM;
                        goto unmap_er;
                }
                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 =
                                        IOVA_MASK(resp->xhci_mem_info.tr_data.iova);
        uadev[card_num].info[info_idx].data_xfer_ring_size = PAGE_SIZE;
        uadev[card_num].info[info_idx].sync_xfer_ring_va =
                                        IOVA_MASK(resp->xhci_mem_info.tr_sync.iova);
        uadev[card_num].info[info_idx].sync_xfer_ring_size = PAGE_SIZE;
        uadev[card_num].info[info_idx].xfer_buf_iova =
                                        IOVA_MASK(resp->xhci_mem_info.xfer_buff.iova);
        uadev[card_num].info[info_idx].xfer_buf_dma =
                                        resp->xhci_mem_info.xfer_buff.dma;
        uadev[card_num].info[info_idx].xfer_buf_size =
                                        resp->xhci_mem_info.xfer_buff.size;
        uadev[card_num].info[info_idx].data_ep_pipe = subs->data_endpoint ?
                                                subs->data_endpoint->pipe : 0;
        uadev[card_num].info[info_idx].sync_ep_pipe = subs->sync_endpoint ?
                                                subs->sync_endpoint->pipe : 0;
        uadev[card_num].info[info_idx].data_ep_idx = subs->data_endpoint ?
                                                subs->data_endpoint->ep_num : 0;
        uadev[card_num].info[info_idx].sync_ep_idx = subs->sync_endpoint ?
                                                subs->sync_endpoint->ep_num : 0;
        uadev[card_num].info[info_idx].xfer_buf_cpu = xfer_buf_cpu;
        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_er:
        uaudio_iommu_unmap(MEM_EVENT_RING, IOVA_BASE, PAGE_SIZE, PAGE_SIZE);
free_sec_ring:
        xhci_sideband_remove_interrupter(uadev[card_num].sb);
        usb_offload_put(subs->dev);
drop_sync_ep:
        if (subs->sync_endpoint) {
                uaudio_iommu_unmap(MEM_XFER_RING,
                                   IOVA_MASK(resp->xhci_mem_info.tr_sync.iova),
                                   PAGE_SIZE, PAGE_SIZE);
                xhci_sideband_remove_endpoint(uadev[card_num].sb,
                        usb_pipe_endpoint(subs->dev, subs->sync_endpoint->pipe));
        }
drop_data_ep:
        uaudio_iommu_unmap(MEM_XFER_RING, IOVA_MASK(resp->xhci_mem_info.tr_data.iova),
                           PAGE_SIZE, PAGE_SIZE);
        xhci_sideband_remove_endpoint(uadev[card_num].sb,
                        usb_pipe_endpoint(subs->dev, subs->data_endpoint->pipe));

        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 uaudio_qmi_svc *svc = uaudio_svc;
        struct snd_usb_audio *chip = NULL;
        struct snd_usb_substream *subs;
        struct usb_host_endpoint *ep;
        int datainterval = -EINVAL;
        int info_idx = -EINVAL;
        struct intf_info *info;
        u8 pcm_card_num;
        u8 pcm_dev_num;
        u8 direction;
        int 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->usb_token & QMI_STREAM_REQ_CARD_NUM_MASK) >> 16;
        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;
        }

        scoped_guard(mutex, &chip->mutex) {
                if (req_msg->enable) {
                        if (info_idx < 0 || chip->system_suspend || subs->opened) {
                                ret = -EBUSY;
                                goto response;
                        }
                        subs->opened = 1;
                }
        }

        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);
                if (ret < 0) {
                        guard(mutex)(&chip->mutex);
                        subs->opened = 0;
                }
        } 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);
                guard(mutex)(&chip->mutex);
                subs->opened = 0;
        }

response:
        if (!req_msg->enable && ret != -EINVAL && ret != -ENODEV) {
                guard(mutex)(&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(&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(void)
{
        uaudio_qdev = kzalloc_obj(*uaudio_qdev);
        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;
}

/* Populates ppcm_idx array with supported PCM indexes */
static int qc_usb_audio_offload_fill_avail_pcms(struct snd_usb_audio *chip,
                                                struct snd_soc_usb_device *sdev)
{
        struct snd_usb_stream *as;
        struct snd_usb_substream *subs;
        int idx = 0;

        list_for_each_entry(as, &chip->pcm_list, list) {
                subs = &as->substream[SNDRV_PCM_STREAM_PLAYBACK];
                if (subs->ep_num) {
                        sdev->ppcm_idx[idx] = as->pcm->device;
                        idx++;
                }
                /*
                 * Break if the current index exceeds the number of possible
                 * playback streams counted from the UAC descriptors.
                 */
                if (idx >= sdev->num_playback)
                        break;
        }

        return -1;
}

/**
 * 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_interface *intf = chip->intf[chip->num_interfaces - 1];
        struct usb_interface_descriptor *altsd;
        struct usb_host_interface *alts;
        struct snd_soc_usb_device *sdev;
        struct xhci_sideband *sb;

        /*
         * If there is no priv_data, or no playback paths, the connected
         * device doesn't support offloading.  Avoid populating entries for
         * this device.
         */
        if (!snd_soc_usb_find_priv_data(uaudio_qdev->auxdev->dev.parent) ||
            !usb_qmi_get_pcm_num(chip, 0))
                return;

        guard(mutex)(&qdev_mutex);
        guard(mutex)(&chip->mutex);
        if (!uadev[chip->card->number].chip) {
                sdev = kzalloc_obj(*sdev);
                if (!sdev)
                        return;

                sb = xhci_sideband_register(intf, XHCI_SIDEBAND_VENDOR,
                                            uaudio_sideband_notifier);
                if (!sb)
                        goto free_sdev;
        } else {
                sb = uadev[chip->card->number].sb;
                sdev = uadev[chip->card->number].sdev;
        }

        uadev[chip->card->number].sb = sb;
        uadev[chip->card->number].chip = chip;
        uadev[chip->card->number].sdev = sdev;

        alts = &intf->altsetting[0];
        altsd = get_iface_desc(alts);

        /* Wait until all PCM devices are populated before notifying soc-usb */
        if (altsd->bInterfaceNumber == chip->last_iface) {
                sdev->num_playback = usb_qmi_get_pcm_num(chip, 0);

                /*
                 * Allocate playback pcm index array based on number of possible
                 * playback paths within the UAC descriptors.
                 */
                sdev->ppcm_idx = kcalloc(sdev->num_playback, sizeof(unsigned int),
                                         GFP_KERNEL);
                if (!sdev->ppcm_idx)
                        goto unreg_xhci;

                qc_usb_audio_offload_fill_avail_pcms(chip, sdev);
                sdev->card_idx = chip->card->number;
                sdev->chip_idx = chip->index;

                snd_usb_offload_create_ctl(chip, uaudio_qdev->auxdev->dev.parent);
                snd_soc_usb_connect(uaudio_qdev->auxdev->dev.parent, sdev);
        }

        return;

unreg_xhci:
        xhci_sideband_unregister(sb);
        uadev[chip->card->number].sb = NULL;
free_sdev:
        kfree(sdev);
        uadev[chip->card->number].sdev = NULL;
        uadev[chip->card->number].chip = NULL;
}

/**
 * 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 uaudio_dev *dev;
        int card_num;

        if (!chip)
                return;

        card_num = chip->card->number;
        if (card_num >= SNDRV_CARDS)
                return;

        guard(mutex)(&qdev_mutex);
        guard(mutex)(&chip->mutex);
        dev = &uadev[card_num];

        /* Device has already been cleaned up, or never populated */
        if (!dev->chip)
                return;

        /* cleaned up already */
        if (!dev->udev)
                goto done;

        uaudio_send_disconnect_ind(chip);
        uaudio_dev_cleanup(dev);
done:
        /*
         * 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) {
                snd_soc_usb_disconnect(uaudio_qdev->auxdev->dev.parent, dev->sdev);
                xhci_sideband_unregister(dev->sb);
                dev->chip = NULL;
                kfree(dev->sdev->ppcm_idx);
                kfree(dev->sdev);
                dev->sdev = NULL;
        }
}

/**
 * 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);
        int card_num;

        if (!chip)
                return;

        card_num = chip->card->number;
        if (card_num >= SNDRV_CARDS)
                return;

        guard(mutex)(&qdev_mutex);
        guard(mutex)(&chip->mutex);

        uaudio_send_disconnect_ind(chip);
}

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 qc_usb_audio_probe(struct auxiliary_device *auxdev,
                          const struct auxiliary_device_id *id)

{
        struct uaudio_qmi_svc *svc;
        int ret;

        svc = kzalloc_obj(*svc);
        if (!svc)
                return -ENOMEM;

        svc->uaudio_svc_hdl = kzalloc_obj(*svc->uaudio_svc_hdl);
        if (!svc->uaudio_svc_hdl) {
                ret = -ENOMEM;
                goto free_svc;
        }

        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);

        uaudio_svc = svc;

        qc_usb_audio_offload_init_qmi_dev();
        uaudio_qdev->auxdev = auxdev;

        ret = snd_usb_register_platform_ops(&offload_ops);
        if (ret < 0)
                goto release_qmi;

        snd_usb_rediscover_devices();

        return 0;

release_qmi:
        qc_usb_audio_cleanup_qmi_dev();
        qmi_handle_release(svc->uaudio_svc_hdl);
free_svc:
        kfree(svc);

        return ret;
}

static void qc_usb_audio_remove(struct auxiliary_device *auxdev)
{
        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);

        qc_usb_audio_cleanup_qmi_dev();

        qmi_handle_release(svc->uaudio_svc_hdl);
        kfree(svc);
        uaudio_svc = NULL;
}

static const struct auxiliary_device_id qc_usb_audio_table[] = {
        { .name = "q6usb.qc-usb-audio-offload" },
        {},
};
MODULE_DEVICE_TABLE(auxiliary, qc_usb_audio_table);

static struct auxiliary_driver qc_usb_audio_offload_drv = {
        .name = "qc-usb-audio-offload",
        .id_table = qc_usb_audio_table,
        .probe = qc_usb_audio_probe,
        .remove = qc_usb_audio_remove,
};
module_auxiliary_driver(qc_usb_audio_offload_drv);

MODULE_DESCRIPTION("QC USB Audio Offloading");
MODULE_LICENSE("GPL");