> +config QC_USB_AUDIO_OFFLOAD
> + tristate "Qualcomm Audio Offload driver"
"Qualcomm USB Audio Offload driver"
> + select SND_PCM
depends on SND_USB_AUDIO ?
> + 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 qc-audio-offload.
> +#include <linux/ctype.h>
> +#include <linux/moduleparam.h>
> +#include <linux/module.h>
> +#include <linux/usb.h>
> +#include <linux/init.h>
alphabetical order?
> +#include <linux/usb/hcd.h>
> +#include <linux/usb/xhci-intr.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 "../midi.h"
> +#include "../mixer.h"
> +#include "../proc.h"
> +#include "../quirks.h"
> +#include "../endpoint.h"
> +#include "../helper.h"
> +#include "../pcm.h"
> +#include "../format.h"
> +#include "../power.h"
> +#include "../stream.h"
> +#include "../media.h"
this looks weird, are all these needed?
> +
> +#define SND_PCM_CARD_NUM_MASK 0xffff0000
> +#define SND_PCM_DEV_NUM_MASK 0xff00
> +#define SND_PCM_STREAM_DIRECTION 0xff
The prefix looks wrong, or it duplicates SND_PCM stuff?
> +
> +/* 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_interrupter *ir;
> + 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 card_num;
> + 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;
> +};
This looks too detailed, isnt' that a duplication of other structures
that exist in the regular USB audio part?
There's nothing that looks QCOM-specific anyways.
> +
> +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,
> +};
prefixes better than 'MEM'?
> +
> +/* 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_audio_device_speed_enum_v01
> +get_speed_info(enum usb_device_speed udev_speed)
> +{
> + switch (udev_speed) {
> + case USB_SPEED_LOW:
> + return USB_AUDIO_DEVICE_SPEED_LOW_V01;
> + case USB_SPEED_FULL:
> + return USB_AUDIO_DEVICE_SPEED_FULL_V01;
> + case USB_SPEED_HIGH:
> + return USB_AUDIO_DEVICE_SPEED_HIGH_V01;
> + case USB_SPEED_SUPER:
> + return USB_AUDIO_DEVICE_SPEED_SUPER_V01;
> + case USB_SPEED_SUPER_PLUS:
> + return USB_AUDIO_DEVICE_SPEED_SUPER_PLUS_V01;
> + default:
> + return USB_AUDIO_DEVICE_SPEED_INVALID_V01;
> + }
> +}
this doesn't look qcom-specific, why is this here?
> +
> +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);
> +}
this doesn't look qcom-specific either, is this a set of helpers that
need to be moved somewhere else?
> +/**
> + * 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;
> +
> + if (subs->data_endpoint || subs->sync_endpoint) {
> + close_endpoints(chip, subs);
> +
> + mutex_lock(&chip->mutex);
> + subs->cur_audiofmt = NULL;
> + mutex_unlock(&chip->mutex);
> + }
> +
> + snd_usb_autosuspend(chip);
> +}
also not qcom-specific?
> +/* kref release callback when all streams are disabled */
what does "all streams disabled" mean, and when does this happen?
> +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);
> +}
> +static int __init qc_usb_audio_offload_init(void)
> +{
> + struct uaudio_qmi_svc *svc;
> + int ret;
> +
> + ret = snd_usb_register_platform_ops(&offload_ops);
> + if (ret < 0)
> + return ret;
so what happens if snd_usb is blacklisted or takes time to probe?
This seems to assume a timing dependency when USB is initialized/probed
first?
> +
> + svc = kzalloc(sizeof(struct uaudio_qmi_svc), GFP_KERNEL);
> + if (!svc) {
> + ret = -ENOMEM;
> + goto unreg_ops;
> + }
> +
> + 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;
> +
> + return 0;
> +
> +free_wq:
> + destroy_workqueue(svc->uaudio_wq);
> +free_svc:
> + kfree(svc);
> +unreg_ops:
> + snd_usb_unregister_platform_ops();
> +
> + return ret;
> +}
> +
> +static void __exit qc_usb_audio_offload_exit(void)
> +{
> + struct uaudio_qmi_svc *svc = uaudio_svc;
> +
> + qmi_handle_release(svc->uaudio_svc_hdl);
> + flush_workqueue(svc->uaudio_wq);
> + destroy_workqueue(svc->uaudio_wq);
> + kfree(svc);
> + uaudio_svc = NULL;
> + snd_usb_unregister_platform_ops();
> +}
> +
> +module_init(qc_usb_audio_offload_init);
> +module_exit(qc_usb_audio_offload_exit);
what causes this module to be loaded?
> +
> +MODULE_DESCRIPTION("QC USB Audio Offloading");
> +MODULE_LICENSE("GPL");
> diff --git a/sound/usb/qcom/usb_audio_qmi_v01.c b/sound/usb/qcom/usb_audio_qmi_v01.c
> new file mode 100644
> index 000000000000..1a0f2f579786
> --- /dev/null
> +++ b/sound/usb/qcom/usb_audio_qmi_v01.c
> @@ -0,0 +1,892 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
> + */
> +
> +#include <linux/soc/qcom/qmi.h>
> +
> +#include "usb_audio_qmi_v01.h"
> +
> +static struct qmi_elem_info mem_info_v01_ei[] = {
> + {
> + .data_type = QMI_UNSIGNED_8_BYTE,
> + .elem_len = 1,
> + .elem_size = sizeof(u64),
> + .array_type = NO_ARRAY,
> + .tlv_type = 0,
> + .offset = offsetof(struct mem_info_v01, va),
> + },
maybe move these arrays to a different patch that we don't need to
scroll-through or review...
> + {
> + .data_type = QMI_UNSIGNED_8_BYTE,
> + .elem_len = 1,
> + .elem_size = sizeof(u64),
> + .array_type = NO_ARRAY,
> + .tlv_type = 0,
> + .offset = offsetof(struct mem_info_v01, pa),
> + },
> + {
> + .data_type = QMI_UNSIGNED_4_BYTE,
> + .elem_len = 1,
> + .elem_size = sizeof(u32),
> + .array_type = NO_ARRAY,
> + .tlv_type = 0,
> + .offset = offsetof(struct mem_info_v01, size),
> + },
> + {
> + .data_type = QMI_EOTI,
> + .array_type = NO_ARRAY,
> + .tlv_type = QMI_COMMON_TLV_TYPE,
> + },
> +};
