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diff --git a/sound/usb/line6/pcm.h b/sound/usb/line6/pcm.h
new file mode 100644
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+++ b/sound/usb/line6/pcm.h
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+/*
+ * Line6 Linux USB driver - 0.9.1beta
+ *
+ * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
+ *
+ *	This program is free software; you can redistribute it and/or
+ *	modify it under the terms of the GNU General Public License as
+ *	published by the Free Software Foundation, version 2.
+ *
+ */
+
+/*
+	PCM interface to POD series devices.
+*/
+
+#ifndef PCM_H
+#define PCM_H
+
+#include <sound/pcm.h>
+
+#include "driver.h"
+#include "usbdefs.h"
+
+/* number of URBs */
+#define LINE6_ISO_BUFFERS	2
+
+/*
+	number of USB frames per URB
+	The Line6 Windows driver always transmits two frames per packet, but
+	the Linux driver performs significantly better (i.e., lower latency)
+	with only one frame per packet.
+*/
+#define LINE6_ISO_PACKETS	1
+
+/* in a "full speed" device (such as the PODxt Pro) this means 1ms */
+#define LINE6_ISO_INTERVAL	1
+
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+#define LINE6_IMPULSE_DEFAULT_PERIOD 100
+#endif
+
+/*
+	Get substream from Line6 PCM data structure
+*/
+#define get_substream(line6pcm, stream)	\
+		(line6pcm->pcm->streams[stream].substream)
+
+/*
+	PCM mode bits.
+
+	There are several features of the Line6 USB driver which require PCM
+	data to be exchanged with the device:
+	*) PCM playback and capture via ALSA
+	*) software monitoring (for devices without hardware monitoring)
+	*) optional impulse response measurement
+	However, from the device's point of view, there is just a single
+	capture and playback stream, which must be shared between these
+	subsystems. It is therefore necessary to maintain the state of the
+	subsystems with respect to PCM usage. We define several constants of
+	the form LINE6_BIT_PCM_<subsystem>_<direction>_<resource> with the
+	following meanings:
+	*) <subsystem> is one of
+	-) ALSA: PCM playback and capture via ALSA
+	-) MONITOR: software monitoring
+	-) IMPULSE: optional impulse response measurement
+	*) <direction> is one of
+	-) PLAYBACK: audio output (from host to device)
+	-) CAPTURE: audio input (from device to host)
+	*) <resource> is one of
+	-) BUFFER: buffer required by PCM data stream
+	-) STREAM: actual PCM data stream
+
+	The subsystems call line6_pcm_acquire() to acquire the (shared)
+	resources needed for a particular operation (e.g., allocate the buffer
+	for ALSA playback or start the capture stream for software monitoring).
+	When a resource is no longer needed, it is released by calling
+	line6_pcm_release(). Buffer allocation and stream startup are handled
+	separately to allow the ALSA kernel driver to perform them at
+	appropriate places (since the callback which starts a PCM stream is not
+	allowed to sleep).
+*/
+enum {
+	/* individual bit indices: */
+	LINE6_INDEX_PCM_ALSA_PLAYBACK_BUFFER,
+	LINE6_INDEX_PCM_ALSA_PLAYBACK_STREAM,
+	LINE6_INDEX_PCM_ALSA_CAPTURE_BUFFER,
+	LINE6_INDEX_PCM_ALSA_CAPTURE_STREAM,
+	LINE6_INDEX_PCM_MONITOR_PLAYBACK_BUFFER,
+	LINE6_INDEX_PCM_MONITOR_PLAYBACK_STREAM,
+	LINE6_INDEX_PCM_MONITOR_CAPTURE_BUFFER,
+	LINE6_INDEX_PCM_MONITOR_CAPTURE_STREAM,
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	LINE6_INDEX_PCM_IMPULSE_PLAYBACK_BUFFER,
+	LINE6_INDEX_PCM_IMPULSE_PLAYBACK_STREAM,
+	LINE6_INDEX_PCM_IMPULSE_CAPTURE_BUFFER,
+	LINE6_INDEX_PCM_IMPULSE_CAPTURE_STREAM,
+#endif
+	LINE6_INDEX_PAUSE_PLAYBACK,
+	LINE6_INDEX_PREPARED,
+
+#define LINE6_BIT(x) LINE6_BIT_ ## x = 1 << LINE6_INDEX_ ## x
+
+	/* individual bit masks: */
+	LINE6_BIT(PCM_ALSA_PLAYBACK_BUFFER),
+	LINE6_BIT(PCM_ALSA_PLAYBACK_STREAM),
+	LINE6_BIT(PCM_ALSA_CAPTURE_BUFFER),
+	LINE6_BIT(PCM_ALSA_CAPTURE_STREAM),
+	LINE6_BIT(PCM_MONITOR_PLAYBACK_BUFFER),
+	LINE6_BIT(PCM_MONITOR_PLAYBACK_STREAM),
+	LINE6_BIT(PCM_MONITOR_CAPTURE_BUFFER),
+	LINE6_BIT(PCM_MONITOR_CAPTURE_STREAM),
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	LINE6_BIT(PCM_IMPULSE_PLAYBACK_BUFFER),
+	LINE6_BIT(PCM_IMPULSE_PLAYBACK_STREAM),
+	LINE6_BIT(PCM_IMPULSE_CAPTURE_BUFFER),
+	LINE6_BIT(PCM_IMPULSE_CAPTURE_STREAM),
+#endif
+	LINE6_BIT(PAUSE_PLAYBACK),
+	LINE6_BIT(PREPARED),
+
+	/* combined bit masks (by operation): */
+	LINE6_BITS_PCM_ALSA_BUFFER =
+	    LINE6_BIT_PCM_ALSA_PLAYBACK_BUFFER |
+	    LINE6_BIT_PCM_ALSA_CAPTURE_BUFFER,
+
+	LINE6_BITS_PCM_ALSA_STREAM =
+	    LINE6_BIT_PCM_ALSA_PLAYBACK_STREAM |
+	    LINE6_BIT_PCM_ALSA_CAPTURE_STREAM,
+
+	LINE6_BITS_PCM_MONITOR =
+	    LINE6_BIT_PCM_MONITOR_PLAYBACK_BUFFER |
+	    LINE6_BIT_PCM_MONITOR_PLAYBACK_STREAM |
+	    LINE6_BIT_PCM_MONITOR_CAPTURE_BUFFER |
+	    LINE6_BIT_PCM_MONITOR_CAPTURE_STREAM,
+
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	LINE6_BITS_PCM_IMPULSE =
+	    LINE6_BIT_PCM_IMPULSE_PLAYBACK_BUFFER |
+	    LINE6_BIT_PCM_IMPULSE_PLAYBACK_STREAM |
+	    LINE6_BIT_PCM_IMPULSE_CAPTURE_BUFFER |
+	    LINE6_BIT_PCM_IMPULSE_CAPTURE_STREAM,
+#endif
+
+	/* combined bit masks (by direction): */
+	LINE6_BITS_PLAYBACK_BUFFER =
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	    LINE6_BIT_PCM_IMPULSE_PLAYBACK_BUFFER |
+#endif
+	    LINE6_BIT_PCM_ALSA_PLAYBACK_BUFFER |
+	    LINE6_BIT_PCM_MONITOR_PLAYBACK_BUFFER,
+
+	LINE6_BITS_PLAYBACK_STREAM =
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	    LINE6_BIT_PCM_IMPULSE_PLAYBACK_STREAM |
+#endif
+	    LINE6_BIT_PCM_ALSA_PLAYBACK_STREAM |
+	    LINE6_BIT_PCM_MONITOR_PLAYBACK_STREAM,
+
+	LINE6_BITS_CAPTURE_BUFFER =
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	    LINE6_BIT_PCM_IMPULSE_CAPTURE_BUFFER |
+#endif
+	    LINE6_BIT_PCM_ALSA_CAPTURE_BUFFER |
+	    LINE6_BIT_PCM_MONITOR_CAPTURE_BUFFER,
+
+	LINE6_BITS_CAPTURE_STREAM =
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	    LINE6_BIT_PCM_IMPULSE_CAPTURE_STREAM |
+#endif
+	    LINE6_BIT_PCM_ALSA_CAPTURE_STREAM |
+	    LINE6_BIT_PCM_MONITOR_CAPTURE_STREAM,
+
+	LINE6_BITS_STREAM =
+	    LINE6_BITS_PLAYBACK_STREAM |
+	    LINE6_BITS_CAPTURE_STREAM
+};
+
+struct line6_pcm_properties {
+	struct snd_pcm_hardware snd_line6_playback_hw, snd_line6_capture_hw;
+	struct snd_pcm_hw_constraint_ratdens snd_line6_rates;
+	int bytes_per_frame;
+};
+
+struct snd_line6_pcm {
+	/**
+		 Pointer back to the Line6 driver data structure.
+	*/
+	struct usb_line6 *line6;
+
+	/**
+		 Properties.
+	*/
+	struct line6_pcm_properties *properties;
+
+	/**
+		 ALSA pcm stream
+	*/
+	struct snd_pcm *pcm;
+
+	/**
+		 URBs for audio playback.
+	*/
+	struct urb *urb_audio_out[LINE6_ISO_BUFFERS];
+
+	/**
+		 URBs for audio capture.
+	*/
+	struct urb *urb_audio_in[LINE6_ISO_BUFFERS];
+
+	/**
+		 Temporary buffer for playback.
+		 Since the packet size is not known in advance, this buffer is
+		 large enough to store maximum size packets.
+	*/
+	unsigned char *buffer_out;
+
+	/**
+		 Temporary buffer for capture.
+		 Since the packet size is not known in advance, this buffer is
+		 large enough to store maximum size packets.
+	*/
+	unsigned char *buffer_in;
+
+	/**
+		 Previously captured frame (for software monitoring).
+	*/
+	unsigned char *prev_fbuf;
+
+	/**
+		 Size of previously captured frame (for software monitoring).
+	*/
+	int prev_fsize;
+
+	/**
+		 Free frame position in the playback buffer.
+	*/
+	snd_pcm_uframes_t pos_out;
+
+	/**
+		 Count processed bytes for playback.
+		 This is modulo period size (to determine when a period is
+		 finished).
+	*/
+	unsigned bytes_out;
+
+	/**
+		 Counter to create desired playback sample rate.
+	*/
+	unsigned count_out;
+
+	/**
+		 Playback period size in bytes
+	*/
+	unsigned period_out;
+
+	/**
+		 Processed frame position in the playback buffer.
+		 The contents of the output ring buffer have been consumed by
+		 the USB subsystem (i.e., sent to the USB device) up to this
+		 position.
+	*/
+	snd_pcm_uframes_t pos_out_done;
+
+	/**
+		 Count processed bytes for capture.
+		 This is modulo period size (to determine when a period is
+		 finished).
+	*/
+	unsigned bytes_in;
+
+	/**
+		 Counter to create desired capture sample rate.
+	*/
+	unsigned count_in;
+
+	/**
+		 Capture period size in bytes
+	*/
+	unsigned period_in;
+
+	/**
+		 Processed frame position in the capture buffer.
+		 The contents of the output ring buffer have been consumed by
+		 the USB subsystem (i.e., sent to the USB device) up to this
+		 position.
+	*/
+	snd_pcm_uframes_t pos_in_done;
+
+	/**
+		 Bit mask of active playback URBs.
+	*/
+	unsigned long active_urb_out;
+
+	/**
+		 Maximum size of USB packet.
+	*/
+	int max_packet_size;
+
+	/**
+		 Bit mask of active capture URBs.
+	*/
+	unsigned long active_urb_in;
+
+	/**
+		 Bit mask of playback URBs currently being unlinked.
+	*/
+	unsigned long unlink_urb_out;
+
+	/**
+		 Bit mask of capture URBs currently being unlinked.
+	*/
+	unsigned long unlink_urb_in;
+
+	/**
+		 Spin lock to protect updates of the playback buffer positions (not
+		 contents!)
+	*/
+	spinlock_t lock_audio_out;
+
+	/**
+		 Spin lock to protect updates of the capture buffer positions (not
+		 contents!)
+	*/
+	spinlock_t lock_audio_in;
+
+	/**
+		 Spin lock to protect trigger.
+	*/
+	spinlock_t lock_trigger;
+
+	/**
+		 PCM playback volume (left and right).
+	*/
+	int volume_playback[2];
+
+	/**
+		 PCM monitor volume.
+	*/
+	int volume_monitor;
+
+#ifdef CONFIG_LINE6_USB_IMPULSE_RESPONSE
+	/**
+		 Volume of impulse response test signal (if zero, test is disabled).
+	*/
+	int impulse_volume;
+
+	/**
+		 Period of impulse response test signal.
+	*/
+	int impulse_period;
+
+	/**
+		 Counter for impulse response test signal.
+	*/
+	int impulse_count;
+#endif
+
+	/**
+		 Several status bits (see LINE6_BIT_*).
+	*/
+	unsigned long flags;
+
+	int last_frame_in, last_frame_out;
+};
+
+extern int line6_init_pcm(struct usb_line6 *line6,
+			  struct line6_pcm_properties *properties);
+extern int snd_line6_trigger(struct snd_pcm_substream *substream, int cmd);
+extern int snd_line6_prepare(struct snd_pcm_substream *substream);
+extern void line6_pcm_disconnect(struct snd_line6_pcm *line6pcm);
+extern int line6_pcm_acquire(struct snd_line6_pcm *line6pcm, int channels);
+extern int line6_pcm_release(struct snd_line6_pcm *line6pcm, int channels);
+
+#endif