v4.19.13 snapshot.
diff --git a/sound/usb/card.h b/sound/usb/card.h
new file mode 100644
index 0000000..ac785d1
--- /dev/null
+++ b/sound/usb/card.h
@@ -0,0 +1,174 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __USBAUDIO_CARD_H
+#define __USBAUDIO_CARD_H
+
+#define MAX_NR_RATES	1024
+#define MAX_PACKS	6		/* per URB */
+#define MAX_PACKS_HS	(MAX_PACKS * 8)	/* in high speed mode */
+#define MAX_URBS	12
+#define SYNC_URBS	4	/* always four urbs for sync */
+#define MAX_QUEUE	18	/* try not to exceed this queue length, in ms */
+
+struct audioformat {
+	struct list_head list;
+	u64 formats;			/* ALSA format bits */
+	unsigned int channels;		/* # channels */
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	unsigned int frame_size;	/* samples per frame for non-audio */
+	int iface;			/* interface number */
+	unsigned char altsetting;	/* corresponding alternate setting */
+	unsigned char altset_idx;	/* array index of altenate setting */
+	unsigned char attributes;	/* corresponding attributes of cs endpoint */
+	unsigned char endpoint;		/* endpoint */
+	unsigned char ep_attr;		/* endpoint attributes */
+	unsigned char datainterval;	/* log_2 of data packet interval */
+	unsigned char protocol;		/* UAC_VERSION_1/2/3 */
+	unsigned int maxpacksize;	/* max. packet size */
+	unsigned int rates;		/* rate bitmasks */
+	unsigned int rate_min, rate_max;	/* min/max rates */
+	unsigned int nr_rates;		/* number of rate table entries */
+	unsigned int *rate_table;	/* rate table */
+	unsigned char clock;		/* associated clock */
+	struct snd_pcm_chmap_elem *chmap; /* (optional) channel map */
+	bool dsd_dop;			/* add DOP headers in case of DSD samples */
+	bool dsd_bitrev;		/* reverse the bits of each DSD sample */
+	bool dsd_raw;			/* altsetting is raw DSD */
+};
+
+struct snd_usb_substream;
+struct snd_usb_endpoint;
+struct snd_usb_power_domain;
+
+struct snd_urb_ctx {
+	struct urb *urb;
+	unsigned int buffer_size;	/* size of data buffer, if data URB */
+	struct snd_usb_substream *subs;
+	struct snd_usb_endpoint *ep;
+	int index;	/* index for urb array */
+	int packets;	/* number of packets per urb */
+	int packet_size[MAX_PACKS_HS]; /* size of packets for next submission */
+	struct list_head ready_list;
+};
+
+struct snd_usb_endpoint {
+	struct snd_usb_audio *chip;
+
+	int use_count;
+	int ep_num;		/* the referenced endpoint number */
+	int type;		/* SND_USB_ENDPOINT_TYPE_* */
+	unsigned long flags;
+
+	void (*prepare_data_urb) (struct snd_usb_substream *subs,
+				  struct urb *urb);
+	void (*retire_data_urb) (struct snd_usb_substream *subs,
+				 struct urb *urb);
+
+	struct snd_usb_substream *data_subs;
+	struct snd_usb_endpoint *sync_master;
+	struct snd_usb_endpoint *sync_slave;
+
+	struct snd_urb_ctx urb[MAX_URBS];
+
+	struct snd_usb_packet_info {
+		uint32_t packet_size[MAX_PACKS_HS];
+		int packets;
+	} next_packet[MAX_URBS];
+	int next_packet_read_pos, next_packet_write_pos;
+	struct list_head ready_playback_urbs;
+
+	unsigned int nurbs;		/* # urbs */
+	unsigned long active_mask;	/* bitmask of active urbs */
+	unsigned long unlink_mask;	/* bitmask of unlinked urbs */
+	char *syncbuf;			/* sync buffer for all sync URBs */
+	dma_addr_t sync_dma;		/* DMA address of syncbuf */
+
+	unsigned int pipe;		/* the data i/o pipe */
+	unsigned int freqn;		/* nominal sampling rate in fs/fps in Q16.16 format */
+	unsigned int freqm;		/* momentary sampling rate in fs/fps in Q16.16 format */
+	int	   freqshift;		/* how much to shift the feedback value to get Q16.16 */
+	unsigned int freqmax;		/* maximum sampling rate, used for buffer management */
+	unsigned int phase;		/* phase accumulator */
+	unsigned int maxpacksize;	/* max packet size in bytes */
+	unsigned int maxframesize;      /* max packet size in frames */
+	unsigned int max_urb_frames;	/* max URB size in frames */
+	unsigned int curpacksize;	/* current packet size in bytes (for capture) */
+	unsigned int curframesize;      /* current packet size in frames (for capture) */
+	unsigned int syncmaxsize;	/* sync endpoint packet size */
+	unsigned int fill_max:1;	/* fill max packet size always */
+	unsigned int tenor_fb_quirk:1;	/* corrupted feedback data */
+	unsigned int datainterval;      /* log_2 of data packet interval */
+	unsigned int syncinterval;	/* P for adaptive mode, 0 otherwise */
+	unsigned char silence_value;
+	unsigned int stride;
+	int iface, altsetting;
+	int skip_packets;		/* quirks for devices to ignore the first n packets
+					   in a stream */
+
+	spinlock_t lock;
+	struct list_head list;
+};
+
+struct snd_usb_substream {
+	struct snd_usb_stream *stream;
+	struct usb_device *dev;
+	struct snd_pcm_substream *pcm_substream;
+	int direction;	/* playback or capture */
+	int interface;	/* current interface */
+	int endpoint;	/* assigned endpoint */
+	struct audioformat *cur_audiofmt;	/* current audioformat pointer (for hw_params callback) */
+	struct snd_usb_power_domain *str_pd;	/* UAC3 Power Domain for streaming path */
+	snd_pcm_format_t pcm_format;	/* current audio format (for hw_params callback) */
+	unsigned int channels;		/* current number of channels (for hw_params callback) */
+	unsigned int channels_max;	/* max channels in the all audiofmts */
+	unsigned int cur_rate;		/* current rate (for hw_params callback) */
+	unsigned int period_bytes;	/* current period bytes (for hw_params callback) */
+	unsigned int period_frames;	/* current frames per period */
+	unsigned int buffer_periods;	/* current periods per buffer */
+	unsigned int altset_idx;     /* USB data format: index of alternate setting */
+	unsigned int txfr_quirk:1;	/* allow sub-frame alignment */
+	unsigned int tx_length_quirk:1;	/* add length specifier to transfers */
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	unsigned int pkt_offset_adj;	/* Bytes to drop from beginning of packets (for non-compliant devices) */
+
+	unsigned int running: 1;	/* running status */
+
+	unsigned int hwptr_done;	/* processed byte position in the buffer */
+	unsigned int transfer_done;		/* processed frames since last period update */
+	unsigned int frame_limit;	/* limits number of packets in URB */
+
+	/* data and sync endpoints for this stream */
+	unsigned int ep_num;		/* the endpoint number */
+	struct snd_usb_endpoint *data_endpoint;
+	struct snd_usb_endpoint *sync_endpoint;
+	unsigned long flags;
+	bool need_setup_ep;		/* (re)configure EP at prepare? */
+	unsigned int speed;		/* USB_SPEED_XXX */
+
+	u64 formats;			/* format bitmasks (all or'ed) */
+	unsigned int num_formats;		/* number of supported audio formats (list) */
+	struct list_head fmt_list;	/* format list */
+	struct snd_pcm_hw_constraint_list rate_list;	/* limited rates */
+	spinlock_t lock;
+
+	int last_frame_number;          /* stored frame number */
+	int last_delay;                 /* stored delay */
+
+	struct {
+		int marker;
+		int channel;
+		int byte_idx;
+	} dsd_dop;
+
+	bool trigger_tstamp_pending_update; /* trigger timestamp being updated from initial estimate */
+};
+
+struct snd_usb_stream {
+	struct snd_usb_audio *chip;
+	struct snd_pcm *pcm;
+	int pcm_index;
+	unsigned int fmt_type;		/* USB audio format type (1-3) */
+	struct snd_usb_substream substream[2];
+	struct list_head list;
+};
+
+#endif /* __USBAUDIO_CARD_H */