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>
diff --git a/sound/usb/6fire/comm.c b/sound/usb/6fire/comm.c
new file mode 100644
index 0000000..c994daa
--- /dev/null
+++ b/sound/usb/6fire/comm.c
@@ -0,0 +1,176 @@
+/*
+ * Linux driver for TerraTec DMX 6Fire USB
+ *
+ * Device communications
+ *
+ * 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 "comm.h"
+#include "chip.h"
+#include "midi.h"
+
+enum {
+	COMM_EP = 1,
+	COMM_FPGA_EP = 2
+};
+
+static void usb6fire_comm_init_urb(struct comm_runtime *rt, struct urb *urb,
+		u8 *buffer, void *context, void(*handler)(struct urb *urb))
+{
+	usb_init_urb(urb);
+	urb->transfer_buffer = buffer;
+	urb->pipe = usb_sndintpipe(rt->chip->dev, COMM_EP);
+	urb->complete = handler;
+	urb->context = context;
+	urb->interval = 1;
+	urb->dev = rt->chip->dev;
+}
+
+static void usb6fire_comm_receiver_handler(struct urb *urb)
+{
+	struct comm_runtime *rt = urb->context;
+	struct midi_runtime *midi_rt = rt->chip->midi;
+
+	if (!urb->status) {
+		if (rt->receiver_buffer[0] == 0x10) /* midi in event */
+			if (midi_rt)
+				midi_rt->in_received(midi_rt,
+						rt->receiver_buffer + 2,
+						rt->receiver_buffer[1]);
+	}
+
+	if (!rt->chip->shutdown) {
+		urb->status = 0;
+		urb->actual_length = 0;
+		if (usb_submit_urb(urb, GFP_ATOMIC) < 0)
+			snd_printk(KERN_WARNING PREFIX
+					"comm data receiver aborted.\n");
+	}
+}
+
+static void usb6fire_comm_init_buffer(u8 *buffer, u8 id, u8 request,
+		u8 reg, u8 vl, u8 vh)
+{
+	buffer[0] = 0x01;
+	buffer[2] = request;
+	buffer[3] = id;
+	switch (request) {
+	case 0x02:
+		buffer[1] = 0x05; /* length (starting at buffer[2]) */
+		buffer[4] = reg;
+		buffer[5] = vl;
+		buffer[6] = vh;
+		break;
+
+	case 0x12:
+		buffer[1] = 0x0b; /* length (starting at buffer[2]) */
+		buffer[4] = 0x00;
+		buffer[5] = 0x18;
+		buffer[6] = 0x05;
+		buffer[7] = 0x00;
+		buffer[8] = 0x01;
+		buffer[9] = 0x00;
+		buffer[10] = 0x9e;
+		buffer[11] = reg;
+		buffer[12] = vl;
+		break;
+
+	case 0x20:
+	case 0x21:
+	case 0x22:
+		buffer[1] = 0x04;
+		buffer[4] = reg;
+		buffer[5] = vl;
+		break;
+	}
+}
+
+static int usb6fire_comm_send_buffer(u8 *buffer, struct usb_device *dev)
+{
+	int ret;
+	int actual_len;
+
+	ret = usb_interrupt_msg(dev, usb_sndintpipe(dev, COMM_EP),
+			buffer, buffer[1] + 2, &actual_len, HZ);
+	if (ret < 0)
+		return ret;
+	else if (actual_len != buffer[1] + 2)
+		return -EIO;
+	return 0;
+}
+
+static int usb6fire_comm_write8(struct comm_runtime *rt, u8 request,
+		u8 reg, u8 value)
+{
+	u8 buffer[13]; /* 13: maximum length of message */
+
+	usb6fire_comm_init_buffer(buffer, 0x00, request, reg, value, 0x00);
+	return usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+}
+
+static int usb6fire_comm_write16(struct comm_runtime *rt, u8 request,
+		u8 reg, u8 vl, u8 vh)
+{
+	u8 buffer[13]; /* 13: maximum length of message */
+
+	usb6fire_comm_init_buffer(buffer, 0x00, request, reg, vl, vh);
+	return usb6fire_comm_send_buffer(buffer, rt->chip->dev);
+}
+
+int __devinit usb6fire_comm_init(struct sfire_chip *chip)
+{
+	struct comm_runtime *rt = kzalloc(sizeof(struct comm_runtime),
+			GFP_KERNEL);
+	struct urb *urb = &rt->receiver;
+	int ret;
+
+	if (!rt)
+		return -ENOMEM;
+
+	rt->serial = 1;
+	rt->chip = chip;
+	usb_init_urb(urb);
+	rt->init_urb = usb6fire_comm_init_urb;
+	rt->write8 = usb6fire_comm_write8;
+	rt->write16 = usb6fire_comm_write16;
+
+	/* submit an urb that receives communication data from device */
+	urb->transfer_buffer = rt->receiver_buffer;
+	urb->transfer_buffer_length = COMM_RECEIVER_BUFSIZE;
+	urb->pipe = usb_rcvintpipe(chip->dev, COMM_EP);
+	urb->dev = chip->dev;
+	urb->complete = usb6fire_comm_receiver_handler;
+	urb->context = rt;
+	urb->interval = 1;
+	ret = usb_submit_urb(urb, GFP_KERNEL);
+	if (ret < 0) {
+		kfree(rt);
+		snd_printk(KERN_ERR PREFIX "cannot create comm data receiver.");
+		return ret;
+	}
+	chip->comm = rt;
+	return 0;
+}
+
+void usb6fire_comm_abort(struct sfire_chip *chip)
+{
+	struct comm_runtime *rt = chip->comm;
+
+	if (rt)
+		usb_poison_urb(&rt->receiver);
+}
+
+void usb6fire_comm_destroy(struct sfire_chip *chip)
+{
+	kfree(chip->comm);
+	chip->comm = NULL;
+}