ALSA: usb/6fire - Driver for TerraTec DMX 6Fire USB

What is working: Everything except SPDIF
- Hardware Master volume
- PCM 44-192kHz@24 bits, 6 channels out, 4 channels in (analog)
- MIDI in/out
- firmware loading after cold start
- phono/line switching

Signed-off-by: Torsten Schenk <torsten.schenk@zoho.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 689 insertions, 0 deletions

diff --git a/sound/usb/6fire/pcm.c b/sound/usb/6fire/pcm.c
new file mode 100644
index 000000000000..705c88e1964c
--- /dev/null
+++ b/sound/usb/6fire/pcm.c
@@ -0,0 +1,689 @@
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * PCM driver
+ *
+ * Author:	Torsten Schenk <torsten.schenk@zoho.com>
+ * Created:	Jan 01, 2011
+ * Version:	0.3.0
+ * Copyright:	(C) Torsten Schenk
+ *
+ * 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; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include "pcm.h"
+#include "chip.h"
+#include "comm.h"
+
+enum {
+	OUT_N_CHANNELS = 6, IN_N_CHANNELS = 4
+};
+
+/* keep next two synced with
+ * FW_EP_W_MAX_PACKET_SIZE[] and RATES_MAX_PACKET_SIZE */
+static const int rates_in_packet_size[] = { 228, 228, 420, 420, 404, 404 };
+static const int rates_out_packet_size[] = { 228, 228, 420, 420, 604, 604 };
+static const int rates[] = { 44100, 48000, 88200, 96000, 176400, 192000 };
+static const int rates_altsetting[] = { 1, 1, 2, 2, 3, 3 };
+static const int rates_alsaid[] = {
+	SNDRV_PCM_RATE_44100, SNDRV_PCM_RATE_48000,
+	SNDRV_PCM_RATE_88200, SNDRV_PCM_RATE_96000,
+	SNDRV_PCM_RATE_176400, SNDRV_PCM_RATE_192000 };
+
+/* values to write to soundcard register for all samplerates */
+static const u16 rates_6fire_vl[] = {0x00, 0x01, 0x00, 0x01, 0x00, 0x01};
+static const u16 rates_6fire_vh[] = {0x11, 0x11, 0x10, 0x10, 0x00, 0x00};
+
+enum { /* settings for pcm */
+	OUT_EP = 6, IN_EP = 2, MAX_BUFSIZE = 128 * 1024
+};
+
+enum { /* pcm streaming states */
+	STREAM_DISABLED, /* no pcm streaming */
+	STREAM_STARTING, /* pcm streaming requested, waiting to become ready */
+	STREAM_RUNNING, /* pcm streaming running */
+	STREAM_STOPPING
+};
+
+enum { /* pcm sample rates (also index into RATES_XXX[]) */
+	RATE_44KHZ,
+	RATE_48KHZ,
+	RATE_88KHZ,
+	RATE_96KHZ,
+	RATE_176KHZ,
+	RATE_192KHZ
+};
+
+static const struct snd_pcm_hardware pcm_hw = {
+	.info = SNDRV_PCM_INFO_MMAP |
+		SNDRV_PCM_INFO_INTERLEAVED |
+		SNDRV_PCM_INFO_BLOCK_TRANSFER |
+		SNDRV_PCM_INFO_MMAP_VALID |
+		SNDRV_PCM_INFO_BATCH,
+
+	.formats = SNDRV_PCM_FMTBIT_S24_LE,
+
+	.rates = SNDRV_PCM_RATE_44100 |
+		SNDRV_PCM_RATE_48000 |
+		SNDRV_PCM_RATE_88200 |
+		SNDRV_PCM_RATE_96000 |
+		SNDRV_PCM_RATE_176400 |
+		SNDRV_PCM_RATE_192000,
+
+	.rate_min = 44100,
+	.rate_max = 192000,
+	.channels_min = 1,
+	.channels_max = 0, /* set in pcm_open, depending on capture/playback */
+	.buffer_bytes_max = MAX_BUFSIZE,
+	.period_bytes_min = PCM_N_PACKETS_PER_URB * (PCM_MAX_PACKET_SIZE - 4),
+	.period_bytes_max = MAX_BUFSIZE,
+	.periods_min = 2,
+	.periods_max = 1024
+};
+
+static int usb6fire_pcm_set_rate(struct pcm_runtime *rt)
+{
+	int ret;
+	struct usb_device *device = rt->chip->dev;
+	struct comm_runtime *comm_rt = rt->chip->comm;
+
+	if (rt->rate >= ARRAY_SIZE(rates))
+		return -EINVAL;
+	/* disable streaming */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x00, 0x00, 0x00);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error stopping streaming while "
+				"setting samplerate %d.\n", rates[rt->rate]);
+		return ret;
+	}
+
+	ret = usb_set_interface(device, 1, rates_altsetting[rt->rate]);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error setting interface "
+				"altsetting %d for samplerate %d.\n",
+				rates_altsetting[rt->rate], rates[rt->rate]);
+		return ret;
+	}
+
+	/* set soundcard clock */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x01, rates_6fire_vl[rt->rate],
+			rates_6fire_vh[rt->rate]);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error setting samplerate %d.\n",
+				rates[rt->rate]);
+		return ret;
+	}
+
+	/* enable analog inputs and outputs
+	 * (one bit per stereo-channel) */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x02,
+			(1 << (OUT_N_CHANNELS / 2)) - 1,
+			(1 << (IN_N_CHANNELS / 2)) - 1);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error initializing analog channels "
+				"while setting samplerate %d.\n",
+				rates[rt->rate]);
+		return ret;
+	}
+	/* disable digital inputs and outputs */
+	ret = comm_rt->write16(comm_rt, 0x02, 0x03, 0x00, 0x00);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error initializing digital "
+				"channels while setting samplerate %d.\n",
+				rates[rt->rate]);
+		return ret;
+	}
+
+	ret = comm_rt->write16(comm_rt, 0x02, 0x00, 0x00, 0x01);
+	if (ret < 0) {
+		snd_printk(KERN_ERR PREFIX "error starting streaming while "
+				"setting samplerate %d.\n", rates[rt->rate]);
+		return ret;
+	}
+
+	rt->in_n_analog = IN_N_CHANNELS;
+	rt->out_n_analog = OUT_N_CHANNELS;
+	rt->in_packet_size = rates_in_packet_size[rt->rate];
+	rt->out_packet_size = rates_out_packet_size[rt->rate];
+	return 0;
+}
+
+static struct pcm_substream *usb6fire_pcm_get_substream(
+		struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK)
+		return &rt->playback;
+	else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE)
+		return &rt->capture;
+	snd_printk(KERN_ERR PREFIX "error getting pcm substream slot.\n");
+	return NULL;
+}
+
+/* call with stream_mutex locked */
+static void usb6fire_pcm_stream_stop(struct pcm_runtime *rt)
+{
+	int i;
+
+	if (rt->stream_state != STREAM_DISABLED) {
+		for (i = 0; i < PCM_N_URBS; i++) {
+			usb_kill_urb(&rt->in_urbs[i].instance);
+			usb_kill_urb(&rt->out_urbs[i].instance);
+		}
+		rt->stream_state = STREAM_DISABLED;
+	}
+}
+
+/* call with stream_mutex locked */
+static int usb6fire_pcm_stream_start(struct pcm_runtime *rt)
+{
+	int ret;
+	int i;
+	int k;
+	struct usb_iso_packet_descriptor *packet;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		/* submit our in urbs */
+		rt->stream_wait_cond = false;
+		rt->stream_state = STREAM_STARTING;
+		for (i = 0; i < PCM_N_URBS; i++) {
+			for (k = 0; k < PCM_N_PACKETS_PER_URB; k++) {
+				packet = &rt->in_urbs[i].packets[k];
+				packet->offset = k * rt->in_packet_size;
+				packet->length = rt->in_packet_size;
+				packet->actual_length = 0;
+				packet->status = 0;
+			}
+			ret = usb_submit_urb(&rt->in_urbs[i].instance,
+					GFP_ATOMIC);
+			if (ret) {
+				usb6fire_pcm_stream_stop(rt);
+				return ret;
+			}
+		}
+
+		/* wait for first out urb to return (sent in in urb handler) */
+		wait_event_timeout(rt->stream_wait_queue, rt->stream_wait_cond,
+				HZ);
+		if (rt->stream_wait_cond)
+			rt->stream_state = STREAM_RUNNING;
+		else {
+			usb6fire_pcm_stream_stop(rt);
+			return -EIO;
+		}
+	}
+	return 0;
+}
+
+/* call with substream locked */
+static void usb6fire_pcm_capture(struct pcm_substream *sub, struct pcm_urb *urb)
+{
+	int i;
+	int frame;
+	int frame_count;
+	unsigned int total_length = 0;
+	struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
+	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
+	u32 *src = (u32 *) urb->buffer;
+	u32 *dest = (u32 *) (alsa_rt->dma_area + sub->dma_off
+			* (alsa_rt->frame_bits >> 3));
+	u32 *dest_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
+			* (alsa_rt->frame_bits >> 3));
+	int bytes_per_frame = alsa_rt->channels << 2;
+
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		/* at least 4 header bytes for valid packet.
+		 * after that: 32 bits per sample for analog channels */
+		if (urb->packets[i].actual_length > 4)
+			frame_count = (urb->packets[i].actual_length - 4)
+					/ (rt->in_n_analog << 2);
+		else
+			frame_count = 0;
+
+		src = (u32 *) (urb->buffer + total_length);
+		src++; /* skip leading 4 bytes of every packet */
+		total_length += urb->packets[i].length;
+		for (frame = 0; frame < frame_count; frame++) {
+			memcpy(dest, src, bytes_per_frame);
+			dest += alsa_rt->channels;
+			src += rt->in_n_analog;
+			sub->dma_off++;
+			sub->period_off++;
+			if (dest == dest_end) {
+				sub->dma_off = 0;
+				dest = (u32 *) alsa_rt->dma_area;
+			}
+		}
+	}
+}
+
+/* call with substream locked */
+static void usb6fire_pcm_playback(struct pcm_substream *sub,
+		struct pcm_urb *urb)
+{
+	int i;
+	int frame;
+	int frame_count;
+	struct pcm_runtime *rt = snd_pcm_substream_chip(sub->instance);
+	struct snd_pcm_runtime *alsa_rt = sub->instance->runtime;
+	u32 *src = (u32 *) (alsa_rt->dma_area + sub->dma_off
+			* (alsa_rt->frame_bits >> 3));
+	u32 *src_end = (u32 *) (alsa_rt->dma_area + alsa_rt->buffer_size
+			* (alsa_rt->frame_bits >> 3));
+	u32 *dest = (u32 *) urb->buffer;
+	int bytes_per_frame = alsa_rt->channels << 2;
+
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		/* at least 4 header bytes for valid packet.
+		 * after that: 32 bits per sample for analog channels */
+		if (urb->packets[i].length > 4)
+			frame_count = (urb->packets[i].length - 4)
+					/ (rt->out_n_analog << 2);
+		else
+			frame_count = 0;
+		dest++; /* skip leading 4 bytes of every frame */
+		for (frame = 0; frame < frame_count; frame++) {
+			memcpy(dest, src, bytes_per_frame);
+			src += alsa_rt->channels;
+			dest += rt->out_n_analog;
+			sub->dma_off++;
+			sub->period_off++;
+			if (src == src_end) {
+				src = (u32 *) alsa_rt->dma_area;
+				sub->dma_off = 0;
+			}
+		}
+	}
+}
+
+static void usb6fire_pcm_in_urb_handler(struct urb *usb_urb)
+{
+	struct pcm_urb *in_urb = usb_urb->context;
+	struct pcm_urb *out_urb = in_urb->peer;
+	struct pcm_runtime *rt = in_urb->chip->pcm;
+	struct pcm_substream *sub;
+	unsigned long flags;
+	int total_length = 0;
+	int frame_count;
+	int frame;
+	int channel;
+	int i;
+	u8 *dest;
+
+	if (usb_urb->status || rt->panic || rt->stream_state == STREAM_STOPPING)
+		return;
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++)
+		if (in_urb->packets[i].status) {
+			rt->panic = true;
+			return;
+		}
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		snd_printk(KERN_ERR PREFIX "internal error: "
+				"stream disabled in in-urb handler.\n");
+		return;
+	}
+
+	/* receive our capture data */
+	sub = &rt->capture;
+	spin_lock_irqsave(&sub->lock, flags);
+	if (sub->active) {
+		usb6fire_pcm_capture(sub, in_urb);
+		if (sub->period_off >= sub->instance->runtime->period_size) {
+			sub->period_off %= sub->instance->runtime->period_size;
+			spin_unlock_irqrestore(&sub->lock, flags);
+			snd_pcm_period_elapsed(sub->instance);
+		} else
+			spin_unlock_irqrestore(&sub->lock, flags);
+	} else
+		spin_unlock_irqrestore(&sub->lock, flags);
+
+	/* setup out urb structure */
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++) {
+		out_urb->packets[i].offset = total_length;
+		out_urb->packets[i].length = (in_urb->packets[i].actual_length
+				- 4) / (rt->in_n_analog << 2)
+				* (rt->out_n_analog << 2) + 4;
+		out_urb->packets[i].status = 0;
+		total_length += out_urb->packets[i].length;
+	}
+	memset(out_urb->buffer, 0, total_length);
+
+	/* now send our playback data (if a free out urb was found) */
+	sub = &rt->playback;
+	spin_lock_irqsave(&sub->lock, flags);
+	if (sub->active) {
+		usb6fire_pcm_playback(sub, out_urb);
+		if (sub->period_off >= sub->instance->runtime->period_size) {
+			sub->period_off %= sub->instance->runtime->period_size;
+			spin_unlock_irqrestore(&sub->lock, flags);
+			snd_pcm_period_elapsed(sub->instance);
+		} else
+			spin_unlock_irqrestore(&sub->lock, flags);
+	} else
+		spin_unlock_irqrestore(&sub->lock, flags);
+
+	/* setup the 4th byte of each sample (0x40 for analog channels) */
+	dest = out_urb->buffer;
+	for (i = 0; i < PCM_N_PACKETS_PER_URB; i++)
+		if (out_urb->packets[i].length >= 4) {
+			frame_count = (out_urb->packets[i].length - 4)
+					/ (rt->out_n_analog << 2);
+			*(dest++) = 0xaa;
+			*(dest++) = 0xaa;
+			*(dest++) = frame_count;
+			*(dest++) = 0x00;
+			for (frame = 0; frame < frame_count; frame++)
+				for (channel = 0;
+						channel < rt->out_n_analog;
+						channel++) {
+					dest += 3; /* skip sample data */
+					*(dest++) = 0x40;
+				}
+		}
+	usb_submit_urb(&out_urb->instance, GFP_ATOMIC);
+	usb_submit_urb(&in_urb->instance, GFP_ATOMIC);
+}
+
+static void usb6fire_pcm_out_urb_handler(struct urb *usb_urb)
+{
+	struct pcm_urb *urb = usb_urb->context;
+	struct pcm_runtime *rt = urb->chip->pcm;
+
+	if (rt->stream_state == STREAM_STARTING) {
+		rt->stream_wait_cond = true;
+		wake_up(&rt->stream_wait_queue);
+	}
+}
+
+static int usb6fire_pcm_open(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = NULL;
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+
+	if (rt->panic)
+		return -EPIPE;
+
+	mutex_lock(&rt->stream_mutex);
+	alsa_rt->hw = pcm_hw;
+
+	if (alsa_sub->stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		if (rt->rate >= 0)
+			alsa_rt->hw.rates = rates_alsaid[rt->rate];
+		alsa_rt->hw.channels_max = OUT_N_CHANNELS;
+		sub = &rt->playback;
+	} else if (alsa_sub->stream == SNDRV_PCM_STREAM_CAPTURE) {
+		if (rt->rate >= 0)
+			alsa_rt->hw.rates = rates_alsaid[rt->rate];
+		alsa_rt->hw.channels_max = IN_N_CHANNELS;
+		sub = &rt->capture;
+	}
+
+	if (!sub) {
+		mutex_unlock(&rt->stream_mutex);
+		snd_printk(KERN_ERR PREFIX "invalid stream type.\n");
+		return -EINVAL;
+	}
+
+	sub->instance = alsa_sub;
+	sub->active = false;
+	mutex_unlock(&rt->stream_mutex);
+	return 0;
+}
+
+static int usb6fire_pcm_close(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	unsigned long flags;
+
+	if (rt->panic)
+		return 0;
+
+	mutex_lock(&rt->stream_mutex);
+	if (sub) {
+		/* deactivate substream */
+		spin_lock_irqsave(&sub->lock, flags);
+		sub->instance = NULL;
+		sub->active = false;
+		spin_unlock_irqrestore(&sub->lock, flags);
+
+		/* all substreams closed? if so, stop streaming */
+		if (!rt->playback.instance && !rt->capture.instance) {
+			usb6fire_pcm_stream_stop(rt);
+			rt->rate = -1;
+		}
+	}
+	mutex_unlock(&rt->stream_mutex);
+	return 0;
+}
+
+static int usb6fire_pcm_hw_params(struct snd_pcm_substream *alsa_sub,
+		struct snd_pcm_hw_params *hw_params)
+{
+	return snd_pcm_lib_malloc_pages(alsa_sub,
+			params_buffer_bytes(hw_params));
+}
+
+static int usb6fire_pcm_hw_free(struct snd_pcm_substream *alsa_sub)
+{
+	return snd_pcm_lib_free_pages(alsa_sub);
+}
+
+static int usb6fire_pcm_prepare(struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct snd_pcm_runtime *alsa_rt = alsa_sub->runtime;
+	int i;
+	int ret;
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	mutex_lock(&rt->stream_mutex);
+	sub->dma_off = 0;
+	sub->period_off = 0;
+
+	if (rt->stream_state == STREAM_DISABLED) {
+		rt->rate = -1;
+		for (i = 0; i < ARRAY_SIZE(rates); i++)
+			if (alsa_rt->rate == rates[i]) {
+				rt->rate = i;
+				break;
+			}
+		if (rt->rate == -1) {
+			mutex_unlock(&rt->stream_mutex);
+			snd_printk("invalid rate %d in prepare.\n",
+					alsa_rt->rate);
+			return -EINVAL;
+		}
+
+		ret = usb6fire_pcm_set_rate(rt);
+		if (ret) {
+			mutex_unlock(&rt->stream_mutex);
+			return ret;
+		}
+		ret = usb6fire_pcm_stream_start(rt);
+		if (ret) {
+			mutex_unlock(&rt->stream_mutex);
+			snd_printk(KERN_ERR PREFIX
+					"could not start pcm stream.\n");
+			return ret;
+		}
+	}
+	mutex_unlock(&rt->stream_mutex);
+	return 0;
+}
+
+static int usb6fire_pcm_trigger(struct snd_pcm_substream *alsa_sub, int cmd)
+{
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	unsigned long flags;
+
+	if (rt->panic)
+		return -EPIPE;
+	if (!sub)
+		return -ENODEV;
+
+	switch (cmd) {
+	case SNDRV_PCM_TRIGGER_START:
+	case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
+		spin_lock_irqsave(&sub->lock, flags);
+		sub->active = true;
+		spin_unlock_irqrestore(&sub->lock, flags);
+		return 0;
+
+	case SNDRV_PCM_TRIGGER_STOP:
+	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
+		spin_lock_irqsave(&sub->lock, flags);
+		sub->active = false;
+		spin_unlock_irqrestore(&sub->lock, flags);
+		return 0;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+static snd_pcm_uframes_t usb6fire_pcm_pointer(
+		struct snd_pcm_substream *alsa_sub)
+{
+	struct pcm_substream *sub = usb6fire_pcm_get_substream(alsa_sub);
+	struct pcm_runtime *rt = snd_pcm_substream_chip(alsa_sub);
+	unsigned long flags;
+	snd_pcm_uframes_t ret;
+
+	if (rt->panic || !sub)
+		return SNDRV_PCM_STATE_XRUN;
+
+	spin_lock_irqsave(&sub->lock, flags);
+	ret = sub->dma_off;
+	spin_unlock_irqrestore(&sub->lock, flags);
+	return ret;
+}
+
+static struct snd_pcm_ops pcm_ops = {
+	.open = usb6fire_pcm_open,
+	.close = usb6fire_pcm_close,
+	.ioctl = snd_pcm_lib_ioctl,
+	.hw_params = usb6fire_pcm_hw_params,
+	.hw_free = usb6fire_pcm_hw_free,
+	.prepare = usb6fire_pcm_prepare,
+	.trigger = usb6fire_pcm_trigger,
+	.pointer = usb6fire_pcm_pointer,
+};
+
+static void __devinit usb6fire_pcm_init_urb(struct pcm_urb *urb,
+		struct sfire_chip *chip, bool in, int ep,
+		void (*handler)(struct urb *))
+{
+	urb->chip = chip;
+	usb_init_urb(&urb->instance);
+	urb->instance.transfer_buffer = urb->buffer;
+	urb->instance.transfer_buffer_length =
+			PCM_N_PACKETS_PER_URB * PCM_MAX_PACKET_SIZE;
+	urb->instance.dev = chip->dev;
+	urb->instance.pipe = in ? usb_rcvisocpipe(chip->dev, ep)
+			: usb_sndisocpipe(chip->dev, ep);
+	urb->instance.interval = 1;
+	urb->instance.transfer_flags = URB_ISO_ASAP;
+	urb->instance.complete = handler;
+	urb->instance.context = urb;
+	urb->instance.number_of_packets = PCM_N_PACKETS_PER_URB;
+}
+
+int __devinit usb6fire_pcm_init(struct sfire_chip *chip)
+{
+	int i;
+	int ret;
+	struct snd_pcm *pcm;
+	struct pcm_runtime *rt =
+			kzalloc(sizeof(struct pcm_runtime), GFP_KERNEL);
+
+	if (!rt)
+		return -ENOMEM;
+
+	rt->chip = chip;
+	rt->stream_state = STREAM_DISABLED;
+	rt->rate = -1;
+	init_waitqueue_head(&rt->stream_wait_queue);
+	mutex_init(&rt->stream_mutex);
+
+	spin_lock_init(&rt->playback.lock);
+	spin_lock_init(&rt->capture.lock);
+
+	for (i = 0; i < PCM_N_URBS; i++) {
+		usb6fire_pcm_init_urb(&rt->in_urbs[i], chip, true, IN_EP,
+				usb6fire_pcm_in_urb_handler);
+		usb6fire_pcm_init_urb(&rt->out_urbs[i], chip, false, OUT_EP,
+				usb6fire_pcm_out_urb_handler);
+
+		rt->in_urbs[i].peer = &rt->out_urbs[i];
+		rt->out_urbs[i].peer = &rt->in_urbs[i];
+	}
+
+	ret = snd_pcm_new(chip->card, "DMX6FireUSB", 0, 1, 1, &pcm);
+	if (ret < 0) {
+		kfree(rt);
+		snd_printk(KERN_ERR PREFIX "cannot create pcm instance.\n");
+		return ret;
+	}
+
+	pcm->private_data = rt;
+	strcpy(pcm->name, "DMX 6Fire USB");
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &pcm_ops);
+	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &pcm_ops);
+
+	ret = snd_pcm_lib_preallocate_pages_for_all(pcm,
+			SNDRV_DMA_TYPE_CONTINUOUS,
+			snd_dma_continuous_data(GFP_KERNEL),
+			MAX_BUFSIZE, MAX_BUFSIZE);
+	if (ret) {
+		kfree(rt);
+		snd_printk(KERN_ERR PREFIX
+				"error preallocating pcm buffers.\n");
+		return ret;
+	}
+	rt->instance = pcm;
+
+	chip->pcm = rt;
+	return 0;
+}
+
+void usb6fire_pcm_abort(struct sfire_chip *chip)
+{
+	struct pcm_runtime *rt = chip->pcm;
+	int i;
+
+	if (rt) {
+		rt->panic = true;
+
+		if (rt->playback.instance)
+			snd_pcm_stop(rt->playback.instance,
+					SNDRV_PCM_STATE_XRUN);
+		if (rt->capture.instance)
+			snd_pcm_stop(rt->capture.instance,
+					SNDRV_PCM_STATE_XRUN);
+
+		for (i = 0; i < PCM_N_URBS; i++) {
+			usb_poison_urb(&rt->in_urbs[i].instance);
+			usb_poison_urb(&rt->out_urbs[i].instance);
+		}
+
+	}
+}
+
+void usb6fire_pcm_destroy(struct sfire_chip *chip)
+{
+	kfree(chip->pcm);
+	chip->pcm = NULL;
+}