--- /dev/null
+/*
+ * Line 6 Linux USB driver
+ *
+ * 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"
+
+/* number of URBs */
+#define LINE6_ISO_BUFFERS 2
+
+/*
+ number of USB frames per URB
+ The Line 6 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
+
+#define LINE6_IMPULSE_DEFAULT_PERIOD 100
+
+/*
+ Get substream from Line 6 PCM data structure
+*/
+#define get_substream(line6pcm, stream) \
+ (line6pcm->pcm->streams[stream].substream)
+
+/*
+ PCM mode bits.
+
+ There are several features of the Line 6 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 two bit flags, "opened" and "running", for each playback
+ or capture stream. Both can contain the bit flag corresponding to
+ LINE6_STREAM_* type,
+ LINE6_STREAM_PCM = ALSA PCM playback or capture
+ LINE6_STREAM_MONITOR = software monitoring
+ IMPULSE = optional impulse response measurement
+ The opened flag indicates whether the buffer is allocated while
+ the running flag indicates whether the stream is running.
+
+ For monitor or impulse operations, the driver needs to call
+ line6_pcm_acquire() or line6_pcm_release() with the appropriate
+ LINE6_STREAM_* flag.
+*/
+
+/* stream types */
+enum {
+ LINE6_STREAM_PCM,
+ LINE6_STREAM_MONITOR,
+ LINE6_STREAM_IMPULSE,
+};
+
+/* misc bit flags for PCM operation */
+enum {
+ LINE6_FLAG_PAUSE_PLAYBACK,
+ LINE6_FLAG_PREPARED,
+};
+
+struct line6_pcm_properties {
+ struct snd_pcm_hardware playback_hw, capture_hw;
+ struct snd_pcm_hw_constraint_ratdens rates;
+ int bytes_per_frame;
+};
+
+struct line6_pcm_stream {
+ /* allocated URBs */
+ struct urb *urbs[LINE6_ISO_BUFFERS];
+
+ /* Temporary buffer;
+ * Since the packet size is not known in advance, this buffer is
+ * large enough to store maximum size packets.
+ */
+ unsigned char *buffer;
+
+ /* Free frame position in the buffer. */
+ snd_pcm_uframes_t pos;
+
+ /* Count processed bytes;
+ * This is modulo period size (to determine when a period is finished).
+ */
+ unsigned bytes;
+
+ /* Counter to create desired sample rate */
+ unsigned count;
+
+ /* period size in bytes */
+ unsigned period;
+
+ /* Processed frame position in the buffer;
+ * The contents of the 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_done;
+
+ /* Bit mask of active URBs */
+ unsigned long active_urbs;
+
+ /* Bit mask of URBs currently being unlinked */
+ unsigned long unlink_urbs;
+
+ /* Spin lock to protect updates of the buffer positions (not contents)
+ */
+ spinlock_t lock;
+
+ /* Bit flags for operational stream types */
+ unsigned long opened;
+
+ /* Bit flags for running stream types */
+ unsigned long running;
+
+ int last_frame;
+};
+
+struct snd_line6_pcm {
+ /* Pointer back to the Line 6 driver data structure */
+ struct usb_line6 *line6;
+
+ /* Properties. */
+ struct line6_pcm_properties *properties;
+
+ /* ALSA pcm stream */
+ struct snd_pcm *pcm;
+
+ /* protection to state changes of in/out streams */
+ struct mutex state_mutex;
+
+ /* Capture and playback streams */
+ struct line6_pcm_stream in;
+ struct line6_pcm_stream out;
+
+ /* Previously captured frame (for software monitoring) */
+ unsigned char *prev_fbuf;
+
+ /* Size of previously captured frame (for software monitoring) */
+ int prev_fsize;
+
+ /* Maximum size of USB packet */
+ int max_packet_size;
+
+ /* PCM playback volume (left and right) */
+ int volume_playback[2];
+
+ /* PCM monitor volume */
+ int volume_monitor;
+
+ /* 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;
+
+ /* Several status bits (see LINE6_FLAG_*) */
+ unsigned long flags;
+};
+
+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 int snd_line6_hw_params(struct snd_pcm_substream *substream,
+ struct snd_pcm_hw_params *hw_params);
+extern int snd_line6_hw_free(struct snd_pcm_substream *substream);
+extern snd_pcm_uframes_t snd_line6_pointer(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 type);
+extern void line6_pcm_release(struct snd_line6_pcm *line6pcm, int type);
+
+#endif
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