[PATCH] MIDI driver for Behringer BCD2000 USB device

[PATCH] MIDI driver for Behringer BCD2000 USB device

[Mario Kicherer]

This patch adds initial support for the Behringer BCD2000 USB DJ controller.
At the moment, only the MIDI part of the device is working, i.e. knobs,
buttons and LEDs.

I also plan to add support for the audio part, but I assume that this will
require more effort than the rather simple MIDI interface. Progress can be
tracked at https://github.com/anyc/snd-usb-bcd2000.

Signed-off-by: Mario Kicherer <dev@kicherer.org>
---
 sound/usb/Kconfig           |  14 +
 sound/usb/Makefile          |   2 +-
 sound/usb/bcd2000/Makefile  |   3 +
 sound/usb/bcd2000/bcd2000.c | 629 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 647 insertions(+), 1 deletion(-)
 create mode 100644 sound/usb/bcd2000/Makefile
 create mode 100644 sound/usb/bcd2000/bcd2000.c

diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
index de9408b..50af405 100644
--- a/sound/usb/Kconfig
+++ b/sound/usb/Kconfig
@@ -146,5 +146,19 @@ config SND_USB_HIFACE
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-usb-hiface.
 
+config SND_USB_BCD2000
+	tristate "Behringer BCD2000 MIDI driver"
+	select SND_HWDEP
+	select SND_RAWMIDI
+	help
+	  Say Y here to include MIDI support for the Behringer BCD2000 DJ
+	  controller.
+	  
+	  Audio support is still work-in-progress at
+	  https://github.com/anyc/snd-usb-bcd2000
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-usb-bcd2000.
+
 endif	# SND_USB
 
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index abe668f..2b92f0d 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -23,4 +23,4 @@ obj-$(CONFIG_SND_USB_UA101) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_USX2Y) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o
 
-obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/
+obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/
diff --git a/sound/usb/bcd2000/Makefile b/sound/usb/bcd2000/Makefile
new file mode 100644
index 0000000..6540136
--- /dev/null
+++ b/sound/usb/bcd2000/Makefile
@@ -0,0 +1,3 @@
+snd-usb-bcd2000-y := bcd2000.o
+
+obj-$(CONFIG_SND_USB_BCD2000) += snd-usb-bcd2000.o
\ No newline at end of file
diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
new file mode 100644
index 0000000..100c39f
--- /dev/null
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -0,0 +1,629 @@
+/*
+ * Behringer BCD2000 driver
+ *
+ *   Copyright (C) 2014 Mario Kicherer (dev@kicherer.org)
+ *
+ *   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.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the Free Software
+ *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#ifdef CONFIG_USB_DEBUG
+#define DEBUG	1
+#else
+#define DEBUG	0
+#endif
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/rawmidi.h>
+#include "../usbaudio.h"
+#include "../midi.h"
+
+#define DEVICE_NAME "Behringer BCD2000"
+#define DEVICE_SHORTNAME "bcd2000"
+
+#define PREFIX DEVICE_SHORTNAME ": "
+#define BUFSIZE 64
+
+static struct usb_device_id id_table [] = {
+	{ USB_DEVICE(0x1397, 0x00bd) },
+	{ },
+};
+MODULE_DEVICE_TABLE (usb, id_table);
+MODULE_AUTHOR("Mario Kicherer, dev@kicherer.org");
+MODULE_DESCRIPTION("Behringer BCD2000 driver");
+MODULE_LICENSE("GPL");
+
+static int debug = 0;
+module_param(debug, int, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "enable debug output (default: 0)");
+
+static unsigned char set_led_prefix[] = {0x03, 0x00};
+
+static unsigned char bcd2000_init_sequence[] = {
+	0x07, 0x00, 0x00, 0x00, 0x78, 0x48, 0x1c, 0x81,
+	0xc4, 0x00, 0x00, 0x00, 0x5e, 0x53, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff, 0x6c, 0xf3, 0x90, 0xff,
+	0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+	0x18, 0xfa, 0x11, 0xff, 0x14, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0xf2, 0x34, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff};
+
+struct bcd2000 {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf;
+	int card_index;
+	struct snd_pcm *pcm;
+	struct list_head midi_list;
+	spinlock_t lock;
+	struct mutex mutex;
+	
+	int midi_out_active;
+	struct snd_rawmidi *rmidi;
+	struct snd_rawmidi_substream *midi_receive_substream;
+	struct snd_rawmidi_substream *midi_out_substream;
+	
+	unsigned char midi_in_buf[BUFSIZE];
+	unsigned char midi_out_buf[BUFSIZE];
+	
+	unsigned char midi_cmd_buf[3];
+	unsigned char midi_cmd_offset;
+	
+	struct urb * midi_out_urb;
+	struct urb * midi_in_urb;
+};
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
+
+static DEFINE_MUTEX(devices_mutex);
+static unsigned int devices_used;
+static struct usb_driver bcd2000_driver;
+
+
+
+
+
+
+static int bcd2000_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static void bcd2000_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+	
+	if (!bcd2k)
+		return;
+	
+	bcd2k->midi_receive_substream = up ? substream : NULL;
+}
+
+static void bcd2000_midi_handle_input(struct bcd2000 *bcd2k,
+					const unsigned char *buf, int len)
+{
+	unsigned char length, cmd, buf_offset, tocopy;
+	int ret;
+	
+	if (!bcd2k->midi_receive_substream)
+		return;
+	
+	if (DEBUG || debug) {
+		printk(KERN_DEBUG PREFIX "received (%d bytes): ", len);
+		for (ret=0; ret < len; ret++) {
+			printk("%x ", buf[ret]);
+		}
+		printk("\n");
+	}
+	
+	if (len < 2)
+		return;
+	
+	/*
+	 * The BCD2000 sends MIDI commands with 2 or 3 bytes length. In case of
+	 * 2 bytes, the command is the same as before.
+	 *
+	 * Packet structure: mm nn oo (pp)
+	 *	mm: payload length
+	 *	nn: MIDI command or note
+	 *	oo: note or velocity
+	 *	pp: velocity
+	 */
+	
+	length = buf[0];
+	
+	/* ignore packets without payload, should not happen */
+	if (length == 0)
+		return;
+	
+	/*
+	 * The MIDI packets the BCD2000 sends can be arbitrarily truncated or
+	 * concatenated. Therefore, this loop accumulates the bytes from the
+	 * input buffer until a full valid MIDI packet is in the MIDI command
+	 * buffer "midi_cmd_buf".
+	 */
+	
+	buf_offset = 1;
+	while (buf_offset <= length) {
+		cmd = buf[buf_offset];
+		
+		if (bcd2k->midi_cmd_offset == 0 && cmd != 0x90 && cmd != 0xb0) {
+			/*
+			 * this is a 2-byte midi packet -> reuse command byte from
+			 * last midi packet
+			 */
+			bcd2k->midi_cmd_offset = 1;
+		}
+		
+		/* determine the number of bytes we want to copy this time */
+		tocopy = min( 3 - bcd2k->midi_cmd_offset, length - (buf_offset - 1));
+		
+		if (tocopy > 0) {
+			memcpy(&bcd2k->midi_cmd_buf[bcd2k->midi_cmd_offset],
+				&buf[buf_offset], tocopy);
+		} else
+			printk(KERN_ERR PREFIX "error parsing\n");
+		
+		bcd2k->midi_cmd_offset += tocopy;
+		buf_offset += tocopy;
+		
+		/* is our MIDI packet complete? */
+		if (bcd2k->midi_cmd_offset == 3) {
+			if (DEBUG || debug) {
+				printk(KERN_DEBUG PREFIX "send midi packet (%d bytes): ",
+						bcd2k->midi_cmd_offset);
+				for (ret=0;ret< bcd2k->midi_cmd_offset;ret++) {
+					printk("%x ", bcd2k->midi_cmd_buf[ret]);
+				}
+				printk("\n");
+			}
+			
+			/* send MIDI packet */
+			snd_rawmidi_receive(bcd2k->midi_receive_substream,
+						bcd2k->midi_cmd_buf, 3);
+			
+			bcd2k->midi_cmd_offset = 0;
+		}
+	}
+}
+
+static int bcd2000_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct bcd2000 * bcd2k = substream->rmidi->private_data;
+	if (bcd2k->midi_out_active) {
+		usb_free_urb(bcd2k->midi_out_urb);
+		bcd2k->midi_out_active = 0;
+	}
+	return 0;
+}
+
+static void bcd2000_midi_send(struct bcd2000 *bcd2k,
+				struct snd_rawmidi_substream *substream)
+{
+	int len, ret;
+	
+	/* copy the "set LED" command bytes */
+	memcpy(bcd2k->midi_out_buf, set_led_prefix, sizeof(set_led_prefix));
+	
+	/* get MIDI packet */
+	len = snd_rawmidi_transmit(substream, bcd2k->midi_out_buf + 3, BUFSIZE - 3);
+	
+	if (len <= 0)
+		return;
+	
+	/* set payload length */
+	bcd2k->midi_out_buf[2] = len;
+	bcd2k->midi_out_urb->transfer_buffer_length = BUFSIZE;
+	
+	if (DEBUG || debug) {
+		printk(KERN_DEBUG PREFIX "sending: ");
+		for (ret=0;ret< 3 + len;ret++) {
+			printk("%x ", bcd2k->midi_out_buf[ret]);
+		}
+		printk("\n");
+	}
+	
+	/* send packet to the BCD2000 */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
+	if (ret < 0) {
+		printk(KERN_ERR PREFIX
+			   "bcd2000_midi_send(%p): usb_submit_urb() failed,"
+			   "ret=%d, len=%d: ", substream, ret, len);
+		switch (ret) {
+			case -ENOMEM: printk("ENOMEM\n"); break;
+			case -ENODEV: printk("ENODEV\n"); break;
+			case -ENXIO: printk("ENXIO\n"); break;
+			case -EINVAL: printk("EINVAL\n"); break;
+			case -EAGAIN: printk("EAGAIN\n"); break;
+			case -EFBIG: printk("EFBIG\n"); break;
+			case -EPIPE: printk("EPIPE\n"); break;
+			case -EMSGSIZE: printk("EMSGSIZE\n"); break;
+			default: printk("\n");
+		}
+	} else {
+		bcd2k->midi_out_active = 1;
+	}
+}
+
+static void bcd2000_midi_output_done(struct urb* urb)
+{
+	struct bcd2000 * bcd2k = urb->context;
+	
+	bcd2k->midi_out_active = 0;
+	if (urb->status != 0) {
+		printk(KERN_ERR PREFIX "urb status: %d\n", urb->status);
+		return;
+	}
+	
+	if (!bcd2k->midi_out_substream)
+		return;
+	
+	bcd2000_midi_send(bcd2k, bcd2k->midi_out_substream);
+}
+
+static void bcd2000_command_reply_dispatch(struct urb* urb)
+{
+	int ret;
+	struct device *dev = &urb->dev->dev;
+	struct bcd2000 *bcd2k = urb->context;
+	
+	if (urb->status || !bcd2k) {
+		dev_warn(dev, "received urb->status = %i\n", urb->status);
+		return;
+	}
+	
+	if (urb->actual_length > 0)
+		bcd2000_midi_handle_input(bcd2k, urb->transfer_buffer, urb->actual_length);
+	
+	bcd2k->midi_in_urb->actual_length = 0;
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(dev, "unable to submit urb. OOM!?\n");
+}
+
+static void bcd2000_midi_output_trigger(struct snd_rawmidi_substream *substream, int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+	
+	if (up) {
+		bcd2k->midi_out_substream = substream;
+		if (!bcd2k->midi_out_active)
+			bcd2000_midi_send(bcd2k, substream);
+	} else {
+		bcd2k->midi_out_substream = NULL;
+	}
+}
+
+static struct snd_rawmidi_ops bcd2000_midi_output =
+{
+	.open =    bcd2000_midi_output_open,
+	.close =   bcd2000_midi_output_close,
+	.trigger = bcd2000_midi_output_trigger,
+};
+
+static struct snd_rawmidi_ops bcd2000_midi_input =
+{
+	.open =    bcd2000_midi_input_open,
+	.close =   bcd2000_midi_input_close,
+	.trigger = bcd2000_midi_input_trigger,
+};
+
+static void bcd2000_init_device(struct bcd2000 * bcd2k) {
+	int ret;
+	
+	/* copy init sequence into buffer */
+	memcpy(bcd2k->midi_out_buf, bcd2000_init_sequence, 52);
+	bcd2k->midi_out_urb->transfer_buffer_length = 52;
+	
+	/* submit sequence */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
+	if (ret < 0) {
+		printk(KERN_ERR PREFIX
+				"bcd2000_init_device: usb_submit_urb() failed,"
+				"ret=%d: ", ret);
+		switch (ret) {
+			case -ENOMEM: printk("ENOMEM\n"); break;
+			case -ENODEV: printk("ENODEV\n"); break;
+			case -ENXIO: printk("ENXIO\n"); break;
+			case -EINVAL: printk("EINVAL\n"); break;
+			case -EAGAIN: printk("EAGAIN\n"); break;
+			case -EFBIG: printk("EFBIG\n"); break;
+			case -EPIPE: printk("EPIPE\n"); break;
+			case -EMSGSIZE: printk("EMSGSIZE\n"); break;
+			default: printk("\n");
+		}
+	} else {
+		bcd2k->midi_out_active = 1;
+	}
+	
+	/* send empty packet to enable button and controller events */
+	bcd2k->midi_in_urb->actual_length = 0;
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_ATOMIC);
+}
+
+static void bcd2000_init_midi(struct bcd2000 * bcd2k) {
+	int ret;
+	struct snd_rawmidi *rmidi;
+	
+	ret = snd_rawmidi_new(bcd2k->card, bcd2k->card->shortname, 0,
+					1, /* output */
+					1, /* input */
+					&rmidi);
+
+	if (ret < 0)
+		return;
+
+	strlcpy(rmidi->name, bcd2k->card->shortname, sizeof(rmidi->name));
+
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->private_data = bcd2k;
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+					&bcd2000_midi_output);
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+					&bcd2000_midi_input);
+
+	bcd2k->rmidi = rmidi;
+	
+	bcd2k->midi_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	bcd2k->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+	
+	usb_fill_int_urb(bcd2k->midi_in_urb, bcd2k->dev,
+				usb_rcvbulkpipe(bcd2k->dev, 0x81),
+				bcd2k->midi_in_buf, BUFSIZE,
+				bcd2000_command_reply_dispatch, bcd2k, 1);
+	
+	usb_fill_int_urb(bcd2k->midi_out_urb, bcd2k->dev,
+				usb_sndbulkpipe(bcd2k->dev, 0x1),
+				bcd2k->midi_out_buf, BUFSIZE,
+				bcd2000_midi_output_done, bcd2k, 1);
+	
+	bcd2000_init_device(bcd2k);
+}
+
+static void bcd2000_close_midi(struct bcd2000 * bcd2k) {
+	usb_free_urb(bcd2k->midi_out_urb);
+	usb_free_urb(bcd2k->midi_in_urb);
+}
+
+
+
+
+
+/*
+ * general part
+ */
+
+static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
+						struct usb_interface *interface)
+{
+	unsigned int i;
+	struct usb_interface *intf;
+	
+// 	mutex_lock(&ua->mutex);
+// 	free_stream_urbs(&ua->capture);
+// 	free_stream_urbs(&ua->playback);
+// 	mutex_unlock(&ua->mutex);
+// 	free_stream_buffers(ua, &ua->capture);
+// 	free_stream_buffers(ua, &ua->playback);
+	
+	for (i = 0; i < 1; ++i) {
+		mutex_lock(&bcd2k->mutex);
+		intf = bcd2k->intf;
+		bcd2k->intf = NULL;
+		mutex_unlock(&bcd2k->mutex);
+		if (intf) {
+			usb_set_intfdata(intf, NULL);
+			if (intf != interface)
+				usb_driver_release_interface(&bcd2000_driver,
+								intf);
+		}
+	}
+}
+
+static void bcd2000_card_free(struct snd_card *card)
+{
+// 	struct bcd2000 *bcd2k = card->private_data;
+// 	mutex_destroy(&ua->mutex);
+}
+
+static int bcd2000_probe(struct usb_interface *interface, const struct usb_device_id *usb_id)
+{
+	struct snd_card *card;
+	struct bcd2000 * bcd2k;
+	unsigned int card_index;
+	char usb_path[32];
+	int err;
+	
+	
+	mutex_lock(&devices_mutex);
+	
+	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
+		if (enable[card_index] && !(devices_used & (1 << card_index)))
+			break;
+	if (card_index >= SNDRV_CARDS) {
+		mutex_unlock(&devices_mutex);
+		return -ENOENT;
+	}
+	err = snd_card_create(index[card_index], id[card_index], THIS_MODULE,
+					sizeof(*bcd2k), &card);
+	if (err < 0) {
+		mutex_unlock(&devices_mutex);
+		return err;
+	}
+	card->private_free = bcd2000_card_free;
+	bcd2k = card->private_data;
+	bcd2k->dev = interface_to_usbdev(interface);
+	bcd2k->card = card;
+	bcd2k->card_index = card_index;
+	INIT_LIST_HEAD(&bcd2k->midi_list);
+	spin_lock_init(&bcd2k->lock);
+	mutex_init(&bcd2k->mutex);
+	
+// 	INIT_LIST_HEAD(&bcd2k->ready_playback_urbs);
+// 	tasklet_init(&bcd2k->playback_tasklet,
+// 				playback_tasklet, (unsigned long)bcd2k);
+// 	init_waitqueue_head(&bcd2k->alsa_capture_wait);
+// 	init_waitqueue_head(&bcd2k->rate_feedback_wait);
+// 	init_waitqueue_head(&bcd2k->alsa_playback_wait);
+	
+	bcd2k->intf = interface;
+	
+	snd_card_set_dev(card, &interface->dev);
+	
+	strcpy(card->driver, DEVICE_NAME);
+	strcpy(card->shortname, DEVICE_SHORTNAME);
+	usb_make_path(bcd2k->dev, usb_path, sizeof(usb_path));
+	snprintf(bcd2k->card->longname, sizeof(bcd2k->card->longname),
+		    DEVICE_NAME ", at %s, %s speed",
+				usb_path,
+				bcd2k->dev->speed == USB_SPEED_HIGH ? "high" : "full");
+	
+	printk(KERN_INFO PREFIX "%s", bcd2k->card->longname);
+	
+// 	err = alloc_stream_buffers(bcd2k, &bcd2k->capture);
+// 	if (err < 0)
+// 		goto probe_error;
+// 	err = alloc_stream_buffers(bcd2k, &bcd2k->playback);
+// 	if (err < 0)
+// 		goto probe_error;
+// 	
+// 	err = alloc_stream_urbs(bcd2k, &bcd2k->capture, capture_urb_complete);
+// 	if (err < 0)
+// 		goto probe_error;
+// 	err = alloc_stream_urbs(bcd2k, &bcd2k->playback, playback_urb_complete);
+// 	if (err < 0)
+// 		goto probe_error;
+// 	
+// 	err = snd_pcm_new(card, "bcd2000", 0, 1, 1, &bcd2k->pcm);
+// 	if (err < 0)
+// 		goto probe_error;
+// 	bcd2k->pcm->private_data = bcd2k;
+// 	strcpy(bcd2k->pcm->name, "bcd2000");
+// 	snd_pcm_set_ops(bcd2k->pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_pcm_ops);
+// 	snd_pcm_set_ops(bcd2k->pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_pcm_ops);
+	
+// 	err = snd_usbmidi_create(card, bcd2k->intf,
+// 						&bcd2k->midi_list, &midi_quirk);
+// 	if (err < 0)
+// 		goto probe_error;
+	
+	
+	
+	bcd2000_init_midi(bcd2k);
+	
+	
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+	
+	usb_set_intfdata(interface, bcd2k);
+	devices_used |= 1 << card_index;
+	
+	mutex_unlock(&devices_mutex);
+	return 0;
+	
+probe_error:
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+	snd_card_free(card);
+	mutex_unlock(&devices_mutex);
+	return err;
+}
+
+static void bcd2000_disconnect(struct usb_interface *interface)
+{
+	struct bcd2000 *bcd2k = usb_get_intfdata(interface);
+	struct list_head *midi;
+	
+	if (!bcd2k)
+		return;
+	
+	bcd2000_close_midi(bcd2k);
+	
+	mutex_lock(&devices_mutex);
+	
+// 	set_bit(DISCONNECTED, &bcd2k->states);
+// 	wake_up(&bcd2k->rate_feedback_wait);
+	
+	/* make sure that userspace cannot create new requests */
+	snd_card_disconnect(bcd2k->card);
+	
+	/* make sure that there are no pending USB requests */
+	list_for_each(midi, &bcd2k->midi_list)
+		snd_usbmidi_disconnect(midi);
+	
+// 	abort_alsa_playback(bcd2k);
+// 	abort_alsa_capture(bcd2k);
+// 	mutex_lock(&bcd2k->mutex);
+// 	stop_usb_playback(bcd2k);
+// 	stop_usb_capture(bcd2k);
+// 	mutex_unlock(&bcd2k->mutex);
+	
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+	
+	devices_used &= ~(1 << bcd2k->card_index);
+	
+	snd_card_free_when_closed(bcd2k->card);
+	
+	mutex_unlock(&devices_mutex);
+}
+
+static struct usb_driver bcd2000_driver = {
+	.name =	DEVICE_SHORTNAME,
+	.probe =	bcd2000_probe,
+	.disconnect =	bcd2000_disconnect,
+	.id_table =	id_table,
+};
+
+static int __init bcd2000_init(void)
+{
+	int retval = 0;
+	
+	retval = usb_register(&bcd2000_driver);
+	if (retval)
+		printk(KERN_INFO "usb_register failed. Error number %d", retval);
+	return retval;
+}
+
+static void __exit bcd2000_exit(void)
+{
+	usb_deregister(&bcd2000_driver);
+}
+
+module_init (bcd2000_init);
+module_exit (bcd2000_exit);
-- 
1.8.3.2

Re: [PATCH] MIDI driver for Behringer BCD2000 USB device

[Daniel Mack]

Hi Mario,

Thanks for your contribution! I'll comment inline.

On 02/01/2014 08:54 PM, Mario Kicherer wrote:
> diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
> new file mode 100644
> index 0000000..100c39f
> --- /dev/null
> +++ b/sound/usb/bcd2000/bcd2000.c

> +#ifdef CONFIG_USB_DEBUG
> +#define DEBUG	1
> +#else
> +#define DEBUG	0
> +#endif

Please use the define directly instead of introducing a new one.

> +MODULE_DEVICE_TABLE (usb, id_table);
> +MODULE_AUTHOR("Mario Kicherer, dev@kicherer.org");
> +MODULE_DESCRIPTION("Behringer BCD2000 driver");
> +MODULE_LICENSE("GPL");

You can move those lines to the very end of the file, which is slightly
more common.

> +static int debug = 0;
> +module_param(debug, int, S_IRUGO | S_IWUSR);
> +MODULE_PARM_DESC(debug, "enable debug output (default: 0)");
> +
> +static unsigned char set_led_prefix[] = {0x03, 0x00};
> +
> +static unsigned char bcd2000_init_sequence[] = {
> +	0x07, 0x00, 0x00, 0x00, 0x78, 0x48, 0x1c, 0x81,
> +	0xc4, 0x00, 0x00, 0x00, 0x5e, 0x53, 0x4a, 0xf7,
> +	0x18, 0xfa, 0x11, 0xff, 0x6c, 0xf3, 0x90, 0xff,
> +	0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
> +	0x18, 0xfa, 0x11, 0xff, 0x14, 0x00, 0x00, 0x00,
> +	0x00, 0x00, 0x00, 0x00, 0xf2, 0x34, 0x4a, 0xf7,
> +	0x18, 0xfa, 0x11, 0xff};

Your patch has a huge number of style issues, which
scripts/checkpatch.pl will point you to. I got:

total: 743 errors, 96 warnings, 656 lines checked

Can you fix them up an resend please?

> +struct bcd2000 {
> +	struct usb_device *dev;
> +	struct snd_card *card;
> +	struct usb_interface *intf;
> +	int card_index;
> +	struct snd_pcm *pcm;
> +	struct list_head midi_list;
> +	spinlock_t lock;
> +	struct mutex mutex;
> +	
> +	int midi_out_active;
> +	struct snd_rawmidi *rmidi;
> +	struct snd_rawmidi_substream *midi_receive_substream;
> +	struct snd_rawmidi_substream *midi_out_substream;
> +	
> +	unsigned char midi_in_buf[BUFSIZE];
> +	unsigned char midi_out_buf[BUFSIZE];
> +	
> +	unsigned char midi_cmd_buf[3];
> +	unsigned char midi_cmd_offset;
> +	
> +	struct urb * midi_out_urb;
> +	struct urb * midi_in_urb;
> +};
> +
> +static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
> +static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
> +static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
> +
> +static DEFINE_MUTEX(devices_mutex);
> +static unsigned int devices_used;
> +static struct usb_driver bcd2000_driver;
> +

...

> +static void bcd2000_midi_input_trigger(struct snd_rawmidi_substream *substream, int up)
> +{
> +	struct bcd2000 *bcd2k = substream->rmidi->private_data;
> +	
> +	if (!bcd2k)
> +		return;
> +	
> +	bcd2k->midi_receive_substream = up ? substream : NULL;
> +}
> +
> +static void bcd2000_midi_handle_input(struct bcd2000 *bcd2k,
> +					const unsigned char *buf, int len)
> +{
> +	unsigned char length, cmd, buf_offset, tocopy;
> +	int ret;
> +	
> +	if (!bcd2k->midi_receive_substream)
> +		return;
> +	
> +	if (DEBUG || debug) {
> +		printk(KERN_DEBUG PREFIX "received (%d bytes): ", len);
> +		for (ret=0; ret < len; ret++) {
> +			printk("%x ", buf[ret]);
> +		}
> +		printk("\n");
> +	}

We have kernel functions in lib/hexdump.c for this.

> +	
> +	if (len < 2)
> +		return;
> +	
> +	/*
> +	 * The BCD2000 sends MIDI commands with 2 or 3 bytes length. In case of
> +	 * 2 bytes, the command is the same as before.
> +	 *
> +	 * Packet structure: mm nn oo (pp)
> +	 *	mm: payload length
> +	 *	nn: MIDI command or note
> +	 *	oo: note or velocity
> +	 *	pp: velocity
> +	 */
> +	
> +	length = buf[0];
> +	
> +	/* ignore packets without payload, should not happen */
> +	if (length == 0)
> +		return;
> +	
> +	/*
> +	 * The MIDI packets the BCD2000 sends can be arbitrarily truncated or
> +	 * concatenated. Therefore, this loop accumulates the bytes from the
> +	 * input buffer until a full valid MIDI packet is in the MIDI command
> +	 * buffer "midi_cmd_buf".
> +	 */
> +	
> +	buf_offset = 1;
> +	while (buf_offset <= length) {
> +		cmd = buf[buf_offset];
> +		
> +		if (bcd2k->midi_cmd_offset == 0 && cmd != 0x90 && cmd != 0xb0) {
> +			/*
> +			 * this is a 2-byte midi packet -> reuse command byte from
> +			 * last midi packet
> +			 */
> +			bcd2k->midi_cmd_offset = 1;
> +		}
> +		
> +		/* determine the number of bytes we want to copy this time */
> +		tocopy = min( 3 - bcd2k->midi_cmd_offset, length - (buf_offset - 1));
> +		
> +		if (tocopy > 0) {

tocopy is unsigned char, so this check is always true, and the copy
routine can overflow in case bcd2k->midi_cmd_offset < 3.

> +			memcpy(&bcd2k->midi_cmd_buf[bcd2k->midi_cmd_offset],
> +				&buf[buf_offset], tocopy);
> +		} else
> +			printk(KERN_ERR PREFIX "error parsing\n");
> +		
> +		bcd2k->midi_cmd_offset += tocopy;
> +		buf_offset += tocopy;
> +		
> +		/* is our MIDI packet complete? */
> +		if (bcd2k->midi_cmd_offset == 3) {
> +			if (DEBUG || debug) {
> +				printk(KERN_DEBUG PREFIX "send midi packet (%d bytes): ",
> +						bcd2k->midi_cmd_offset);
> +				for (ret=0;ret< bcd2k->midi_cmd_offset;ret++) {
> +					printk("%x ", bcd2k->midi_cmd_buf[ret]);
> +				}
> +				printk("\n");
> +			}

See above.

> +static void bcd2000_midi_send(struct bcd2000 *bcd2k,
> +				struct snd_rawmidi_substream *substream)
> +{
> +	int len, ret;
> +	
> +	/* copy the "set LED" command bytes */
> +	memcpy(bcd2k->midi_out_buf, set_led_prefix, sizeof(set_led_prefix));

Add a BUILD_BUG_ON() here to make sure sizeof(set_led_prefix) is never
bigger than you static buffer.

> +	if (DEBUG || debug) {
> +		printk(KERN_DEBUG PREFIX "sending: ");
> +		for (ret=0;ret< 3 + len;ret++) {
> +			printk("%x ", bcd2k->midi_out_buf[ret]);
> +		}
> +		printk("\n");
> +	}

See above.

> +	/* send packet to the BCD2000 */
> +	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
> +	if (ret < 0) {
> +		printk(KERN_ERR PREFIX
> +			   "bcd2000_midi_send(%p): usb_submit_urb() failed,"
> +			   "ret=%d, len=%d: ", substream, ret, len);
> +		switch (ret) {
> +			case -ENOMEM: printk("ENOMEM\n"); break;
> +			case -ENODEV: printk("ENODEV\n"); break;
> +			case -ENXIO: printk("ENXIO\n"); break;
> +			case -EINVAL: printk("EINVAL\n"); break;
> +			case -EAGAIN: printk("EAGAIN\n"); break;
> +			case -EFBIG: printk("EFBIG\n"); break;
> +			case -EPIPE: printk("EPIPE\n"); break;
> +			case -EMSGSIZE: printk("EMSGSIZE\n"); break;
> +			default: printk("\n");

That you'll fix when following the checkpatch.pl complaints :)

> +	bcd2k->midi_out_active = 0;
> +	if (urb->status != 0) {
> +		printk(KERN_ERR PREFIX "urb status: %d\n", urb->status);

Try to avoid printk() and use snd_printk() or dev_err() instead.

...

> +/*
> + * general part
> + */
> +
> +static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
> +						struct usb_interface *interface)
> +{
> +	unsigned int i;
> +	struct usb_interface *intf;
> +	
> +// 	mutex_lock(&ua->mutex);
> +// 	free_stream_urbs(&ua->capture);
> +// 	free_stream_urbs(&ua->playback);
> +// 	mutex_unlock(&ua->mutex);
> +// 	free_stream_buffers(ua, &ua->capture);
> +// 	free_stream_buffers(ua, &ua->playback);

Please, no dead code. Remove those lines entirely if you don't need them.

> +	for (i = 0; i < 1; ++i) {

Why do you need a loop if it only runs once!?

> +		mutex_lock(&bcd2k->mutex);
> +		intf = bcd2k->intf;
> +		bcd2k->intf = NULL;
> +		mutex_unlock(&bcd2k->mutex);
> +		if (intf) {
> +			usb_set_intfdata(intf, NULL);
> +			if (intf != interface)
> +				usb_driver_release_interface(&bcd2000_driver,
> +								intf);
> +		}
> +	}
> +}
> +
> +static void bcd2000_card_free(struct snd_card *card)
> +{
> +// 	struct bcd2000 *bcd2k = card->private_data;
> +// 	mutex_destroy(&ua->mutex);

Remove dead code.

> +}
> +
> +static int bcd2000_probe(struct usb_interface *interface, const struct usb_device_id *usb_id)
> +{
> +	struct snd_card *card;
> +	struct bcd2000 * bcd2k;
> +	unsigned int card_index;
> +	char usb_path[32];
> +	int err;
> +	
> +	
> +	mutex_lock(&devices_mutex);
> +	
> +	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
> +		if (enable[card_index] && !(devices_used & (1 << card_index)))
> +			break;
> +	if (card_index >= SNDRV_CARDS) {
> +		mutex_unlock(&devices_mutex);
> +		return -ENOENT;
> +	}
> +	err = snd_card_create(index[card_index], id[card_index], THIS_MODULE,
> +					sizeof(*bcd2k), &card);
> +	if (err < 0) {
> +		mutex_unlock(&devices_mutex);
> +		return err;
> +	}
> +	card->private_free = bcd2000_card_free;
> +	bcd2k = card->private_data;
> +	bcd2k->dev = interface_to_usbdev(interface);
> +	bcd2k->card = card;
> +	bcd2k->card_index = card_index;
> +	INIT_LIST_HEAD(&bcd2k->midi_list);
> +	spin_lock_init(&bcd2k->lock);
> +	mutex_init(&bcd2k->mutex);
> +	
> +// 	INIT_LIST_HEAD(&bcd2k->ready_playback_urbs);
> +// 	tasklet_init(&bcd2k->playback_tasklet,
> +// 				playback_tasklet, (unsigned long)bcd2k);
> +// 	init_waitqueue_head(&bcd2k->alsa_capture_wait);
> +// 	init_waitqueue_head(&bcd2k->rate_feedback_wait);
> +// 	init_waitqueue_head(&bcd2k->alsa_playback_wait);

Dito.

> +	bcd2k->intf = interface;
> +	
> +	snd_card_set_dev(card, &interface->dev);
> +	
> +	strcpy(card->driver, DEVICE_NAME);
> +	strcpy(card->shortname, DEVICE_SHORTNAME);
> +	usb_make_path(bcd2k->dev, usb_path, sizeof(usb_path));
> +	snprintf(bcd2k->card->longname, sizeof(bcd2k->card->longname),
> +		    DEVICE_NAME ", at %s, %s speed",
> +				usb_path,
> +				bcd2k->dev->speed == USB_SPEED_HIGH ? "high" : "full");
> +	
> +	printk(KERN_INFO PREFIX "%s", bcd2k->card->longname);
> +	
> +// 	err = alloc_stream_buffers(bcd2k, &bcd2k->capture);
> +// 	if (err < 0)
> +// 		goto probe_error;
> +// 	err = alloc_stream_buffers(bcd2k, &bcd2k->playback);
> +// 	if (err < 0)
> +// 		goto probe_error;
> +// 	
> +// 	err = alloc_stream_urbs(bcd2k, &bcd2k->capture, capture_urb_complete);
> +// 	if (err < 0)
> +// 		goto probe_error;
> +// 	err = alloc_stream_urbs(bcd2k, &bcd2k->playback, playback_urb_complete);
> +// 	if (err < 0)
> +// 		goto probe_error;
> +// 	
> +// 	err = snd_pcm_new(card, "bcd2000", 0, 1, 1, &bcd2k->pcm);
> +// 	if (err < 0)
> +// 		goto probe_error;
> +// 	bcd2k->pcm->private_data = bcd2k;
> +// 	strcpy(bcd2k->pcm->name, "bcd2000");
> +// 	snd_pcm_set_ops(bcd2k->pcm, SNDRV_PCM_STREAM_PLAYBACK, &playback_pcm_ops);
> +// 	snd_pcm_set_ops(bcd2k->pcm, SNDRV_PCM_STREAM_CAPTURE, &capture_pcm_ops);
> +	
> +// 	err = snd_usbmidi_create(card, bcd2k->intf,
> +// 						&bcd2k->midi_list, &midi_quirk);
> +// 	if (err < 0)
> +// 		goto probe_error;

Dito.

I'll do another review once those issues are addressed.


Thanks,
Daniel

Re: [PATCH] MIDI driver for Behringer BCD2000 USB device

[Mario Kicherer]

Hi Daniel,

thank you very much for your comments! I hope I fixed most of the
points but I also have a few questions/comments:

On 05.02.2014 11:54, Daniel Mack wrote:
>> +#ifdef CONFIG_USB_DEBUG
>> +#define DEBUG	1
>> +#else
>> +#define DEBUG	0
>> +#endif
>
> Please use the define directly instead of introducing a new one.

I replaced it with:

#ifndef CONFIG_USB_DEBUG
#define CONFIG_USB_DEBUG 0
#endif

As it can be undefined. I hope that's okay.

> Your patch has a huge number of style issues, which
> scripts/checkpatch.pl will point you to. I got:

Interesting, I copied many issues from other modules. :)
If fixed most of them except these:

WARNING: quoted string split across lines
#310: FILE: sound/usb/bcd2000/bcd2000.c:254:
+                       "bcd2000_midi_send(%p): usb_submit_urb() failed"
+                       "ret=%d, len=%d\n", substream, ret, len);

WARNING: quoted string split across lines
#392: FILE: sound/usb/bcd2000/bcd2000.c:336:
+                               "bcd2000_init_device: usb_submit_urb() 
failed,"
+                               "ret=%d: ", ret);

I don't know how to avoid them, as all strings in one line would be
longer than 80 characters.

>> +		/* determine the number of bytes we want to copy this time */
>> +		tocopy = min( 3 - bcd2k->midi_cmd_offset, length - (buf_offset - 1));
>> +		
>> +		if (tocopy > 0) {
>
> tocopy is unsigned char, so this check is always true, and the copy
> routine can overflow in case bcd2k->midi_cmd_offset < 3.

I don't understand your point here. It could be zero. But I changed it
to a condition that checks if both offsets are within the length of the
two involved buffers.

> Please, no dead code. Remove those lines entirely if you don't need them.

Ah okay, I planned to reactive them with the audio part. But I removed
them for now.

As far as I understood, I should repost the new patch as [PATCH v2]. I
will check this evening if the device still works and send it to the
list afterwards.

Thank you!
Mario

Re: [PATCH] MIDI driver for Behringer BCD2000 USB device

[Daniel Mack]

On 02/05/2014 04:33 PM, Mario Kicherer wrote:
> 
> Hi Daniel,
> 
> thank you very much for your comments! I hope I fixed most of the
> points but I also have a few questions/comments:
> 
> On 05.02.2014 11:54, Daniel Mack wrote:
>>> +#ifdef CONFIG_USB_DEBUG
>>> +#define DEBUG	1
>>> +#else
>>> +#define DEBUG	0
>>> +#endif
>>
>> Please use the define directly instead of introducing a new one.
> 
> I replaced it with:
> 
> #ifndef CONFIG_USB_DEBUG
> #define CONFIG_USB_DEBUG 0
> #endif

No, don't fiddle with CONFIG_* symbols. What I mean is: use the CONFIG_
macro in your code instead if 'DEBUG'. And also, maybe use
CONFIG_SND_DEBUG instead.

> As it can be undefined. I hope that's okay.

Ah, so I'd recommend you move code that depends on this define into a
separate function, and stub it out with a no-op if it's not defined.
Something like this:

#ifdef CONFIG_SND_DEBUG
static void foo_dump()
{
	...
}
#else
static inline void foo_dump() {}
#endif

...
{
	...
	foo_dump();
	...
}

It makes to code more readable if there are less #ifdef.

>> Your patch has a huge number of style issues, which
>> scripts/checkpatch.pl will point you to. I got:
> 
> Interesting, I copied many issues from other modules. :)

You're welcome to send patches to fix them :)
A general rule is: "Do as we say, not as we do".

> If fixed most of them except these:
> 
> WARNING: quoted string split across lines
> #310: FILE: sound/usb/bcd2000/bcd2000.c:254:
> +                       "bcd2000_midi_send(%p): usb_submit_urb() failed"
> +                       "ret=%d, len=%d\n", substream, ret, len);
> 
> WARNING: quoted string split across lines
> #392: FILE: sound/usb/bcd2000/bcd2000.c:336:
> +                               "bcd2000_init_device: usb_submit_urb() 
> failed,"
> +                               "ret=%d: ", ret);
> 
> I don't know how to avoid them, as all strings in one line would be
> longer than 80 characters.

Yep, I'd say that's okay. I'd prefer non-split string over the 80-char
rule. However, consider using __func__ rather than the manual function
name copy; that might solve your problem as well.

>>> +		/* determine the number of bytes we want to copy this time */
>>> +		tocopy = min( 3 - bcd2k->midi_cmd_offset, length - (buf_offset - 1));
>>> +		
>>> +		if (tocopy > 0) {
>>
>> tocopy is unsigned char, so this check is always true, and the copy
>> routine can overflow in case bcd2k->midi_cmd_offset < 3.
> 
> I don't understand your point here. It could be zero.

Yes, I'm sorry. I was looking at the '< 0' condition that can occur if
'bcd2k->midi_cmd_offset < 3'.

> But I changed it
> to a condition that checks if both offsets are within the length of the
> two involved buffers.

Great. Please also double-check whether a maliciously behaving device
could cause any harm to your buffer logic. It's easy to hack a simple
microcontroller to match the driver and then through random stuff at
your routines. Your code must be able to cope with everything it is fed to.

>> Please, no dead code. Remove those lines entirely if you don't need them.
> 
> Ah okay, I planned to reactive them with the audio part. But I removed
> them for now.
> 
> As far as I understood, I should repost the new patch as [PATCH v2].

Correct.

> I
> will check this evening if the device still works and send it to the
> list afterwards.


Thanks,
Daniel

Re: [PATCH] MIDI driver for Behringer BCD2000 USB device

[Daniel Mack]

On 02/20/2014 01:31 PM, Mario Kicherer wrote:
> This patch adds initial support for the Behringer BCD2000 USB DJ controller.
> At the moment, only the MIDI part of the device is working, i.e. knobs,
> buttons and LEDs.
> 
> I also plan to add support for the audio part, but I assume that this will
> require more effort than the rather simple MIDI interface. Progress can be
> tracked at https://github.com/anyc/snd-usb-bcd2000. 

...

> +static int bcd2000_probe(struct usb_interface *interface,
> +				const struct usb_device_id *usb_id)
> +{

...

> +	usb_set_intfdata(interface, bcd2k);
> +	devices_used[card_index/sizeof(int)*8] |=
> +		1 << (card_index%(sizeof(int)*8));
> +

...

> +static void bcd2000_disconnect(struct usb_interface *interface)
> +{

...

> +	devices_used[bcd2k->card_index/sizeof(int)*8] &=
> +		~(1 << (bcd2k->card_index%(sizeof(int)*8)));

We have much nicer ways of doing this :)

Have a look at include/linux/bitmap.h, especially set_bit(), clear_bit()
and DECLARE_BITMAP().

[PATCH] MIDI driver for Behringer BCD2000 USB device

[Mario Kicherer]

This patch adds initial support for the Behringer BCD2000 USB DJ controller.
At the moment, only the MIDI part of the device is working, i.e. knobs,
buttons and LEDs.

I also plan to add support for the audio part, but I assume that this will
require more effort than the rather simple MIDI interface. Progress can be
tracked at https://github.com/anyc/snd-usb-bcd2000.

Changes since v4:
	- devices_used as array to support arbitrary number of SNDRV_CARDS
	- removed unused array "enable"

Changes since v3:
        - applied style and snd_printk changes as suggested by Daniel Mack

Changes since v2:
        - applied more changes from Daniel Mack and Clemens Ladisch

Changes since v1:
        - fixed the various code style issues, thanks to Daniel Mack and
          checkpatch.pl.

Signed-off-by: Mario Kicherer <dev@kicherer.org>
---
 sound/usb/Kconfig           |  13 ++
 sound/usb/Makefile          |   2 +-
 sound/usb/bcd2000/Makefile  |   3 +
 sound/usb/bcd2000/bcd2000.c | 490 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 507 insertions(+), 1 deletion(-)
 create mode 100644 sound/usb/bcd2000/Makefile
 create mode 100644 sound/usb/bcd2000/bcd2000.c

diff --git a/sound/usb/Kconfig b/sound/usb/Kconfig
index de9408b..145653a 100644
--- a/sound/usb/Kconfig
+++ b/sound/usb/Kconfig
@@ -146,5 +146,18 @@ config SND_USB_HIFACE
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-usb-hiface.
 
+config SND_BCD2000
+	tristate "Behringer BCD2000 MIDI driver"
+	select SND_RAWMIDI
+	help
+	  Say Y here to include MIDI support for the Behringer BCD2000 DJ
+	  controller.
+
+	  Audio support is still work-in-progress at
+	  https://github.com/anyc/snd-usb-bcd2000
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called snd-bcd2000.
+
 endif	# SND_USB
 
diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index abe668f..2b92f0d 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile
@@ -23,4 +23,4 @@ obj-$(CONFIG_SND_USB_UA101) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_USX2Y) += snd-usbmidi-lib.o
 obj-$(CONFIG_SND_USB_US122L) += snd-usbmidi-lib.o
 
-obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/
+obj-$(CONFIG_SND) += misc/ usx2y/ caiaq/ 6fire/ hiface/ bcd2000/
diff --git a/sound/usb/bcd2000/Makefile b/sound/usb/bcd2000/Makefile
new file mode 100644
index 0000000..f09ccc0
--- /dev/null
+++ b/sound/usb/bcd2000/Makefile
@@ -0,0 +1,3 @@
+snd-bcd2000-y := bcd2000.o
+
+obj-$(CONFIG_SND_BCD2000) += snd-bcd2000.o
\ No newline at end of file
diff --git a/sound/usb/bcd2000/bcd2000.c b/sound/usb/bcd2000/bcd2000.c
new file mode 100644
index 0000000..847e079
--- /dev/null
+++ b/sound/usb/bcd2000/bcd2000.c
@@ -0,0 +1,490 @@
+/*
+ * Behringer BCD2000 driver
+ *
+ *   Copyright (C) 2014 Mario Kicherer (dev@kicherer.org)
+ *
+ *   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.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/usb/audio.h>
+#include <sound/core.h>
+#include <sound/initval.h>
+#include <sound/rawmidi.h>
+
+#define DEVICE_NAME "Behringer BCD2000"
+#define DEVICE_SHORTNAME "bcd2000"
+
+#define PREFIX DEVICE_SHORTNAME ": "
+#define BUFSIZE 64
+
+static struct usb_device_id id_table[] = {
+	{ USB_DEVICE(0x1397, 0x00bd) },
+	{ },
+};
+
+static unsigned char device_cmd_prefix[] = {0x03, 0x00};
+
+static unsigned char bcd2000_init_sequence[] = {
+	0x07, 0x00, 0x00, 0x00, 0x78, 0x48, 0x1c, 0x81,
+	0xc4, 0x00, 0x00, 0x00, 0x5e, 0x53, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff, 0x6c, 0xf3, 0x90, 0xff,
+	0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+	0x18, 0xfa, 0x11, 0xff, 0x14, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0xf2, 0x34, 0x4a, 0xf7,
+	0x18, 0xfa, 0x11, 0xff
+};
+
+struct bcd2000 {
+	struct usb_device *dev;
+	struct snd_card *card;
+	struct usb_interface *intf;
+	int card_index;
+
+	int midi_out_active;
+	struct snd_rawmidi *rmidi;
+	struct snd_rawmidi_substream *midi_receive_substream;
+	struct snd_rawmidi_substream *midi_out_substream;
+
+	unsigned char midi_in_buf[BUFSIZE];
+	unsigned char midi_out_buf[BUFSIZE];
+
+	struct urb *midi_out_urb;
+	struct urb *midi_in_urb;
+
+	struct usb_anchor anchor;
+};
+
+static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
+static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
+
+static DEFINE_MUTEX(devices_mutex);
+static unsigned int devices_used[SNDRV_CARDS/sizeof(int)];
+static struct usb_driver bcd2000_driver;
+
+#ifdef CONFIG_SND_DEBUG
+static void bcd2000_dump_buffer(const char *prefix, const char *buf, int len)
+{
+	print_hex_dump(KERN_DEBUG, prefix,
+			DUMP_PREFIX_NONE, 16, 1,
+			buf, len, false);
+}
+#else
+static void bcd2000_dump_buffer(const char *prefix, const char *buf, int len) {}
+#endif
+
+static int bcd2000_midi_input_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_input_close(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+/* register midi substream */
+static void bcd2000_midi_input_trigger(struct snd_rawmidi_substream *substream,
+						int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+	bcd2k->midi_receive_substream = up ? substream : NULL;
+}
+
+static void bcd2000_midi_handle_input(struct bcd2000 *bcd2k,
+				const unsigned char *buf, unsigned int len)
+{
+	unsigned int length, tocopy;
+	struct snd_rawmidi_substream *midi_receive_substream;
+
+	midi_receive_substream = ACCESS_ONCE(bcd2k->midi_receive_substream);
+	if (!midi_receive_substream)
+		return;
+
+	bcd2000_dump_buffer(PREFIX "received from device: ", buf, len);
+
+	if (len < 2)
+		return;
+
+	/*
+	 * Packet structure: mm nn oo (pp)
+	 *	mm: payload length
+	 *	nn: MIDI command or note
+	 *	oo: note or velocity
+	 *	pp: velocity
+	 */
+
+	length = buf[0];
+
+	/* ignore packets without payload */
+	if (length == 0)
+		return;
+
+	tocopy = min(length, len-1);
+
+	bcd2000_dump_buffer(PREFIX "sending to userspace: ",
+					&buf[1], tocopy);
+
+	snd_rawmidi_receive(midi_receive_substream,
+					&buf[1], tocopy);
+}
+
+static void bcd2000_midi_send(struct bcd2000 *bcd2k,
+				struct snd_rawmidi_substream *substream)
+{
+	int len, ret;
+
+	BUILD_BUG_ON(sizeof(device_cmd_prefix) >= BUFSIZE);
+
+	/* copy the "set LED" command bytes */
+	memcpy(bcd2k->midi_out_buf, device_cmd_prefix,
+		sizeof(device_cmd_prefix));
+
+	/*
+	 * get MIDI packet and leave space for command prefix
+	 * and payload length
+	 */
+	len = snd_rawmidi_transmit(substream,
+				bcd2k->midi_out_buf + 3, BUFSIZE - 3);
+
+	if (len < 0)
+		dev_err(&bcd2k->dev->dev, "%s: snd_rawmidi_transmit error %d\n",
+				__func__, len);
+
+	if (len <= 0)
+		return;
+
+	/* set payload length */
+	bcd2k->midi_out_buf[2] = len;
+	bcd2k->midi_out_urb->transfer_buffer_length = BUFSIZE;
+
+	bcd2000_dump_buffer(PREFIX "sending to device: ",
+			bcd2k->midi_out_buf, len+3);
+
+	/* send packet to the BCD2000 */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s (%p): usb_submit_urb() failed, ret=%d, len=%d\n",
+			__func__, substream, ret, len);
+	else
+		bcd2k->midi_out_active = 1;
+}
+
+static int bcd2000_midi_output_open(struct snd_rawmidi_substream *substream)
+{
+	return 0;
+}
+
+static int bcd2000_midi_output_close(struct snd_rawmidi_substream *substream)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+
+	if (bcd2k->midi_out_active) {
+		usb_kill_urb(bcd2k->midi_out_urb);
+		bcd2k->midi_out_active = 0;
+	}
+
+	return 0;
+}
+
+/* register midi substream */
+static void bcd2000_midi_output_trigger(struct snd_rawmidi_substream *substream,
+						int up)
+{
+	struct bcd2000 *bcd2k = substream->rmidi->private_data;
+
+	if (up) {
+		bcd2k->midi_out_substream = substream;
+		/* check if there is data userspace wants to send */
+		if (!bcd2k->midi_out_active)
+			bcd2000_midi_send(bcd2k, substream);
+	} else {
+		bcd2k->midi_out_substream = NULL;
+	}
+}
+
+static void bcd2000_output_complete(struct urb *urb)
+{
+	struct bcd2000 *bcd2k = urb->context;
+	struct snd_rawmidi_substream *midi_out_substream;
+
+	bcd2k->midi_out_active = 0;
+
+	if (urb->status != 0)
+		dev_err(&urb->dev->dev,
+			PREFIX "output urb->status: %d\n", urb->status);
+
+	midi_out_substream = ACCESS_ONCE(bcd2k->midi_out_substream);
+	if (!midi_out_substream)
+		return;
+
+	/* check if there is more data userspace wants to send */
+	bcd2000_midi_send(bcd2k, midi_out_substream);
+}
+
+static void bcd2000_input_complete(struct urb *urb)
+{
+	int ret;
+	struct device *dev = &urb->dev->dev;
+	struct bcd2000 *bcd2k = urb->context;
+
+	if (urb->status) {
+		dev_warn(dev, PREFIX "input urb->status: %i\n", urb->status);
+		return;
+	}
+
+	if (!bcd2k)
+		return;
+
+	if (urb->actual_length > 0)
+		bcd2000_midi_handle_input(bcd2k, urb->transfer_buffer,
+					urb->actual_length);
+
+	/* acknowledge received packet */
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_ATOMIC);
+	if (ret < 0)
+		dev_err(dev, "unable to submit urb. OOM!?\n");
+}
+
+static struct snd_rawmidi_ops bcd2000_midi_output = {
+	.open =    bcd2000_midi_output_open,
+	.close =   bcd2000_midi_output_close,
+	.trigger = bcd2000_midi_output_trigger,
+};
+
+static struct snd_rawmidi_ops bcd2000_midi_input = {
+	.open =    bcd2000_midi_input_open,
+	.close =   bcd2000_midi_input_close,
+	.trigger = bcd2000_midi_input_trigger,
+};
+
+static void bcd2000_init_device(struct bcd2000 *bcd2k)
+{
+	int ret;
+
+	init_usb_anchor(&bcd2k->anchor);
+	usb_anchor_urb(bcd2k->midi_out_urb, &bcd2k->anchor);
+	usb_anchor_urb(bcd2k->midi_in_urb, &bcd2k->anchor);
+
+	/* copy init sequence into buffer */
+	memcpy(bcd2k->midi_out_buf, bcd2000_init_sequence, 52);
+	bcd2k->midi_out_urb->transfer_buffer_length = 52;
+
+	/* submit sequence */
+	ret = usb_submit_urb(bcd2k->midi_out_urb, GFP_KERNEL);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s: usb_submit_urb() out failed, ret=%d: ",
+			__func__, ret);
+	else
+		bcd2k->midi_out_active = 1;
+
+	/* send empty packet to enable button and controller events */
+	ret = usb_submit_urb(bcd2k->midi_in_urb, GFP_KERNEL);
+	if (ret < 0)
+		dev_err(&bcd2k->dev->dev, PREFIX
+			"%s: usb_submit_urb() in failed, ret=%d: ",
+			__func__, ret);
+
+	/* ensure initialization is finished */
+	usb_wait_anchor_empty_timeout(&bcd2k->anchor, 1000);
+}
+
+static int bcd2000_init_midi(struct bcd2000 *bcd2k)
+{
+	int ret;
+	struct snd_rawmidi *rmidi;
+
+	ret = snd_rawmidi_new(bcd2k->card, bcd2k->card->shortname, 0,
+					1, /* output */
+					1, /* input */
+					&rmidi);
+
+	if (ret < 0)
+		return ret;
+
+	strlcpy(rmidi->name, bcd2k->card->shortname, sizeof(rmidi->name));
+
+	rmidi->info_flags = SNDRV_RAWMIDI_INFO_DUPLEX;
+	rmidi->private_data = bcd2k;
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_OUTPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_OUTPUT,
+					&bcd2000_midi_output);
+
+	rmidi->info_flags |= SNDRV_RAWMIDI_INFO_INPUT;
+	snd_rawmidi_set_ops(rmidi, SNDRV_RAWMIDI_STREAM_INPUT,
+					&bcd2000_midi_input);
+
+	bcd2k->rmidi = rmidi;
+
+	bcd2k->midi_in_urb = usb_alloc_urb(0, GFP_KERNEL);
+	bcd2k->midi_out_urb = usb_alloc_urb(0, GFP_KERNEL);
+
+	if (!bcd2k->midi_in_urb || !bcd2k->midi_out_urb) {
+		dev_err(&bcd2k->dev->dev, PREFIX "usb_alloc_urb failed\n");
+		return -ENOMEM;
+	}
+
+	usb_fill_int_urb(bcd2k->midi_in_urb, bcd2k->dev,
+				usb_rcvintpipe(bcd2k->dev, 0x81),
+				bcd2k->midi_in_buf, BUFSIZE,
+				bcd2000_input_complete, bcd2k, 1);
+
+	usb_fill_int_urb(bcd2k->midi_out_urb, bcd2k->dev,
+				usb_sndintpipe(bcd2k->dev, 0x1),
+				bcd2k->midi_out_buf, BUFSIZE,
+				bcd2000_output_complete, bcd2k, 1);
+
+	bcd2000_init_device(bcd2k);
+
+	return 0;
+}
+
+static void bcd2000_free_usb_related_resources(struct bcd2000 *bcd2k,
+						struct usb_interface *interface)
+{
+	/* usb_kill_urb not necessary, urb is aborted automatically */
+
+	usb_free_urb(bcd2k->midi_out_urb);
+	usb_free_urb(bcd2k->midi_in_urb);
+
+	if (bcd2k->intf) {
+		usb_set_intfdata(bcd2k->intf, NULL);
+		bcd2k->intf = NULL;
+	}
+}
+
+static int bcd2000_probe(struct usb_interface *interface,
+				const struct usb_device_id *usb_id)
+{
+	struct snd_card *card;
+	struct bcd2000 *bcd2k;
+	unsigned int card_index;
+	char usb_path[32];
+	int err;
+
+	mutex_lock(&devices_mutex);
+
+	for (card_index = 0; card_index < SNDRV_CARDS; ++card_index)
+		if (!(devices_used[card_index/sizeof(int)*8] &
+				(1 << card_index % (sizeof(int)*8))))
+			break;
+
+	if (card_index >= SNDRV_CARDS) {
+		mutex_unlock(&devices_mutex);
+		return -ENOENT;
+	}
+
+	err = snd_card_create(index[card_index], id[card_index], THIS_MODULE,
+					sizeof(*bcd2k), &card);
+	if (err < 0) {
+		mutex_unlock(&devices_mutex);
+		return err;
+	}
+
+	bcd2k = card->private_data;
+	bcd2k->dev = interface_to_usbdev(interface);
+	bcd2k->card = card;
+	bcd2k->card_index = card_index;
+	bcd2k->intf = interface;
+
+	snd_card_set_dev(card, &interface->dev);
+
+	strcpy(card->driver, DEVICE_NAME);
+	strcpy(card->shortname, DEVICE_SHORTNAME);
+	usb_make_path(bcd2k->dev, usb_path, sizeof(usb_path));
+	snprintf(bcd2k->card->longname, sizeof(bcd2k->card->longname),
+			DEVICE_NAME ", at %s",
+			usb_path);
+
+	dev_info(&bcd2k->dev->dev, PREFIX "%s", bcd2k->card->longname);
+
+	err = bcd2000_init_midi(bcd2k);
+	if (err < 0)
+		goto probe_error;
+
+	err = snd_card_register(card);
+	if (err < 0)
+		goto probe_error;
+
+	usb_set_intfdata(interface, bcd2k);
+	devices_used[card_index/sizeof(int)*8] |=
+		1 << (card_index%(sizeof(int)*8));
+
+	mutex_unlock(&devices_mutex);
+	return 0;
+
+probe_error:
+	dev_info(&bcd2k->dev->dev, PREFIX "error during probing");
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+	snd_card_free(card);
+	mutex_unlock(&devices_mutex);
+	return err;
+}
+
+static void bcd2000_disconnect(struct usb_interface *interface)
+{
+	struct bcd2000 *bcd2k = usb_get_intfdata(interface);
+
+	if (!bcd2k)
+		return;
+
+	mutex_lock(&devices_mutex);
+
+	/* make sure that userspace cannot create new requests */
+	snd_card_disconnect(bcd2k->card);
+
+	bcd2000_free_usb_related_resources(bcd2k, interface);
+
+	devices_used[bcd2k->card_index/sizeof(int)*8] &=
+		~(1 << (bcd2k->card_index%(sizeof(int)*8)));
+
+	snd_card_free_when_closed(bcd2k->card);
+
+	mutex_unlock(&devices_mutex);
+}
+
+static struct usb_driver bcd2000_driver = {
+	.name =	DEVICE_SHORTNAME,
+	.probe =	bcd2000_probe,
+	.disconnect =	bcd2000_disconnect,
+	.id_table =	id_table,
+};
+
+static int __init bcd2000_init(void)
+{
+	int retval = 0;
+
+	retval = usb_register(&bcd2000_driver);
+	if (retval)
+		pr_info(PREFIX "usb_register failed. Error: %d", retval);
+	return retval;
+}
+
+static void __exit bcd2000_exit(void)
+{
+	usb_deregister(&bcd2000_driver);
+}
+
+module_init(bcd2000_init);
+module_exit(bcd2000_exit);
+
+MODULE_DEVICE_TABLE(usb, id_table);
+MODULE_AUTHOR("Mario Kicherer, dev@kicherer.org");
+MODULE_DESCRIPTION("Behringer BCD2000 driver");
+MODULE_LICENSE("GPL");
-- 
1.8.3.2