Staging: add line6 usb driver

This is an experimental Linux driver for the guitar amp, cab, and
effects modeller PODxt Pro by Line6 (and similar devices), supporting
the following features:

  - Reading/writing individual parameters
  - Reading/writing complete channel, effects setup, and amp setup data
  - Channel switching
  - Virtual MIDI interface
  - Tuner access
  - Playback/capture/mixer device for any  ALSA-compatible PCM audio
    application
  - Signal routing (record clean/processed  guitar signal, re-amping)

Moreover, preliminary support for the Variax Workbench is included.

From: Markus Grabner <grabner@icg.tugraz.at>
Cc: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/line6/variax.c b/drivers/staging/line6/variax.c
new file mode 100644
index 0000000..edb02a3
--- /dev/null
+++ b/drivers/staging/line6/variax.c
@@ -0,0 +1,501 @@
+/*
+ * Line6 Linux USB driver - 0.8.0
+ *
+ * Copyright (C) 2004-2009 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.
+ *
+ */
+
+#include "driver.h"
+
+#include "audio.h"
+#include "control.h"
+#include "variax.h"
+
+
+#define VARIAX_SYSEX_CODE 7
+#define VARIAX_SYSEX_PARAM 0x3b
+#define VARIAX_SYSEX_ACTIVATE 0x2a
+#define VARIAX_MODEL_HEADER_LENGTH 7
+#define VARIAX_MODEL_MESSAGE_LENGTH 199
+#define VARIAX_OFFSET_ACTIVATE 7
+
+
+static const char variax_activate[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x2a, 0x01,
+	0xf7
+};
+static const char variax_request_bank[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x6d, 0xf7
+};
+static const char variax_request_model1[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x3c, 0x00,
+	0x02, 0x00, 0x00, 0x00, 0x00, 0x03, 0x05, 0x03,
+	0x00, 0x00, 0x00, 0xf7
+};
+static const char variax_request_model2[] = {
+	0xf0, 0x00, 0x01, 0x0c, 0x07, 0x00, 0x3c, 0x00,
+	0x02, 0x00, 0x00, 0x00, 0x00, 0x03, 0x07, 0x03,
+	0x00, 0x00, 0x00, 0xf7
+};
+
+
+/*
+	Decode data transmitted by workbench.
+*/
+static void variax_decode(const unsigned char *raw_data, unsigned char *data, int raw_size)
+{
+	for(; raw_size > 0; raw_size -= 6) {
+		data[2] = raw_data[0] | (raw_data[1] << 4);
+		data[1] = raw_data[2] | (raw_data[3] << 4);
+		data[0] = raw_data[4] | (raw_data[5] << 4);
+		raw_data += 6;
+		data += 3;
+	}
+}
+
+static void variax_activate_timeout(unsigned long arg)
+{
+	struct usb_line6_variax *variax = (struct usb_line6_variax *)arg;
+	variax->buffer_activate[VARIAX_OFFSET_ACTIVATE] = 1;
+	line6_send_raw_message_async(&variax->line6, variax->buffer_activate, sizeof(variax_activate));
+}
+
+/*
+	Send an asynchronous activation request after a given interval.
+*/
+static void variax_activate_delayed(struct usb_line6_variax *variax, int seconds)
+{
+	variax->activate_timer.expires = jiffies + seconds * HZ;
+	variax->activate_timer.function = variax_activate_timeout;
+	variax->activate_timer.data = (unsigned long)variax;
+	add_timer(&variax->activate_timer);
+}
+
+static void variax_startup_timeout(unsigned long arg)
+{
+	struct usb_line6_variax *variax = (struct usb_line6_variax *)arg;
+
+	if(variax->dumpreq.ok)
+		return;
+
+	line6_dump_request_async(&variax->dumpreq, &variax->line6, 0);
+	line6_startup_delayed(&variax->dumpreq, 1, variax_startup_timeout, variax);
+}
+
+/*
+	Process a completely received message.
+*/
+void variax_process_message(struct usb_line6_variax *variax)
+{
+	const unsigned char *buf = variax->line6.buffer_message;
+
+	switch(buf[0]) {
+	case LINE6_PARAM_CHANGE | LINE6_CHANNEL_HOST:
+		switch(buf[1]) {
+		case VARIAXMIDI_volume:
+			variax->volume = buf[2];
+			break;
+
+		case VARIAXMIDI_tone:
+			variax->tone = buf[2];
+		}
+
+		break;
+
+	case LINE6_PROGRAM_CHANGE | LINE6_CHANNEL_DEVICE:
+	case LINE6_PROGRAM_CHANGE | LINE6_CHANNEL_HOST:
+		variax->model = buf[1];
+		line6_dump_request_async(&variax->dumpreq, &variax->line6, 0);
+		break;
+
+	case LINE6_RESET:
+		dev_info(variax->line6.ifcdev, "VARIAX reset\n");
+		variax_activate_delayed(variax, VARIAX_ACTIVATE_DELAY);
+		break;
+
+	case LINE6_SYSEX_BEGIN:
+		if(memcmp(buf + 1, variax_request_model1 + 1, VARIAX_MODEL_HEADER_LENGTH - 1) == 0) {
+			if(variax->line6.message_length == VARIAX_MODEL_MESSAGE_LENGTH) {
+				switch(variax->dumpreq.in_progress) {
+				case VARIAX_DUMP_PASS1:
+					variax_decode(buf + VARIAX_MODEL_HEADER_LENGTH, (unsigned char *)&variax->model_data,
+												(sizeof(variax->model_data.name) + sizeof(variax->model_data.control) / 2) * 2);
+					line6_dump_request_async(&variax->dumpreq, &variax->line6, 1);
+					line6_dump_started(&variax->dumpreq, VARIAX_DUMP_PASS2);
+					break;
+
+				case VARIAX_DUMP_PASS2:
+					/* model name is transmitted twice, so skip it here: */
+					variax_decode(buf + VARIAX_MODEL_HEADER_LENGTH,
+												(unsigned char *)&variax->model_data.control + sizeof(variax->model_data.control) / 2,
+												sizeof(variax->model_data.control) / 2 * 2);
+					variax->dumpreq.ok = 1;
+					line6_dump_request_async(&variax->dumpreq, &variax->line6, 2);
+					line6_dump_started(&variax->dumpreq, VARIAX_DUMP_PASS3);
+				}
+			}
+			else {
+				DEBUG_MESSAGES(dev_err(variax->line6.ifcdev, "illegal length %d of model data\n", variax->line6.message_length));
+				line6_dump_finished(&variax->dumpreq);
+			}
+		}
+		else if(memcmp(buf + 1, variax_request_bank + 1, sizeof(variax_request_bank) - 2) == 0) {
+			memcpy(variax->bank, buf + sizeof(variax_request_bank) - 1, sizeof(variax->bank));
+			variax->dumpreq.ok = 1;
+			line6_dump_finished(&variax->dumpreq);
+		}
+
+		break;
+
+	case LINE6_SYSEX_END:
+		break;
+
+	default:
+		DEBUG_MESSAGES(dev_err(variax->line6.ifcdev, "Variax: unknown message %02X\n", buf[0]));
+	}
+}
+
+/*
+	"read" request on "volume" special file.
+*/
+static ssize_t variax_get_volume(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	return sprintf(buf, "%d\n", variax->volume);
+}
+
+/*
+	"write" request on "volume" special file.
+*/
+static ssize_t variax_set_volume(struct device *dev, DEVICE_ATTRIBUTE const char *buf, size_t count)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	int value = simple_strtoul(buf, NULL, 10);
+
+	if(line6_transmit_parameter(&variax->line6, VARIAXMIDI_volume, value) == 0)
+		variax->volume = value;
+
+	return count;
+}
+
+/*
+	"read" request on "model" special file.
+*/
+static ssize_t variax_get_model(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	return sprintf(buf, "%d\n", variax->model);
+}
+
+/*
+	"write" request on "model" special file.
+*/
+static ssize_t variax_set_model(struct device *dev, DEVICE_ATTRIBUTE const char *buf, size_t count)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata( to_usb_interface(dev));
+	int value = simple_strtoul(buf, NULL, 10);
+
+	if(line6_send_program(&variax->line6, value) == 0)
+		variax->model = value;
+
+	return count;
+}
+
+/*
+	"read" request on "active" special file.
+*/
+static ssize_t variax_get_active(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	return sprintf(buf, "%d\n", variax->buffer_activate[VARIAX_OFFSET_ACTIVATE]);
+}
+
+/*
+	"write" request on "active" special file.
+*/
+static ssize_t variax_set_active(struct device *dev, DEVICE_ATTRIBUTE const char *buf, size_t count)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	int value = simple_strtoul(buf, NULL, 10) ? 1 : 0;
+	variax->buffer_activate[VARIAX_OFFSET_ACTIVATE] = value;
+	line6_send_raw_message_async(&variax->line6, variax->buffer_activate, sizeof(variax_activate));
+	return count;
+}
+
+/*
+	"read" request on "tone" special file.
+*/
+static ssize_t variax_get_tone(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	return sprintf(buf, "%d\n", variax->tone);
+}
+
+/*
+	"write" request on "tone" special file.
+*/
+static ssize_t variax_set_tone(struct device *dev, DEVICE_ATTRIBUTE const char *buf, size_t count)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	int value = simple_strtoul(buf, NULL, 10);
+
+	if(line6_transmit_parameter(&variax->line6, VARIAXMIDI_tone, value) == 0)
+		variax->tone = value;
+
+	return count;
+}
+
+static ssize_t get_string(char *buf, const char *data, int length)
+{
+	int i;
+	memcpy(buf, data, length);
+
+	for(i = length; i--;) {
+		char c = buf[i];
+
+		if((c != 0) && (c != ' '))
+			break;
+	}
+
+	buf[i + 1] = '\n';
+	return i + 2;
+}
+
+/*
+	"read" request on "name" special file.
+*/
+static ssize_t variax_get_name(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	line6_wait_dump(&variax->dumpreq, 0);
+	return get_string(buf, variax->model_data.name, sizeof(variax->model_data.name));
+}
+
+/*
+	"read" request on "bank" special file.
+*/
+static ssize_t variax_get_bank(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	line6_wait_dump(&variax->dumpreq, 0);
+	return get_string(buf, variax->bank, sizeof(variax->bank));
+}
+
+/*
+	"read" request on "dump" special file.
+*/
+static ssize_t variax_get_dump(struct device *dev, DEVICE_ATTRIBUTE char *buf)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	int retval;
+	retval = line6_wait_dump(&variax->dumpreq, 0);
+	if(retval < 0) return retval;
+	memcpy(buf, &variax->model_data.control, sizeof(variax->model_data.control));
+	return sizeof(variax->model_data.control);
+}
+
+#if CREATE_RAW_FILE
+
+/*
+	"write" request on "raw" special file.
+*/
+static ssize_t variax_set_raw2(struct device *dev, DEVICE_ATTRIBUTE const char *buf, size_t count)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(to_usb_interface(dev));
+	int size;
+	int i;
+	char *sysex;
+
+	count -= count % 3;
+	size = count * 2;
+	sysex = variax_alloc_sysex_buffer(variax, VARIAX_SYSEX_PARAM, size);
+
+	if(!sysex)
+		return 0;
+
+	for(i = 0; i < count; i += 3) {
+		const unsigned char *p1 = buf + i;
+		char *p2 = sysex + SYSEX_DATA_OFS + i * 2;
+		p2[0] = p1[2] & 0x0f;
+		p2[1] = p1[2] >> 4;
+		p2[2] = p1[1] & 0x0f;
+		p2[3] = p1[1] >> 4;
+		p2[4] = p1[0] & 0x0f;
+		p2[5] = p1[0] >> 4;
+	}
+
+	line6_send_sysex_message(&variax->line6, sysex, size);
+	kfree(sysex);
+	return count;
+}
+
+#endif
+
+/* Variax workbench special files: */
+static DEVICE_ATTR(model, S_IWUGO | S_IRUGO, variax_get_model, variax_set_model);
+static DEVICE_ATTR(volume, S_IWUGO | S_IRUGO, variax_get_volume, variax_set_volume);
+static DEVICE_ATTR(tone, S_IWUGO | S_IRUGO, variax_get_tone, variax_set_tone);
+static DEVICE_ATTR(name, S_IRUGO, variax_get_name, line6_nop_write);
+static DEVICE_ATTR(bank, S_IRUGO, variax_get_bank, line6_nop_write);
+static DEVICE_ATTR(dump, S_IRUGO, variax_get_dump, line6_nop_write);
+static DEVICE_ATTR(active, S_IWUGO | S_IRUGO, variax_get_active, variax_set_active);
+
+#if CREATE_RAW_FILE
+static DEVICE_ATTR(raw, S_IWUGO, line6_nop_read, line6_set_raw);
+static DEVICE_ATTR(raw2, S_IWUGO, line6_nop_read, variax_set_raw2);
+#endif
+
+
+/*
+	Variax destructor.
+*/
+static void variax_destruct(struct usb_interface *interface)
+{
+	struct usb_line6_variax *variax = usb_get_intfdata(interface);
+	struct usb_line6 *line6;
+
+	if(variax == NULL) return;
+	line6 = &variax->line6;
+	if(line6 == NULL) return;
+	line6_cleanup_audio(line6);
+
+	/* free dump request data: */
+	line6_dumpreq_destructbuf(&variax->dumpreq, 2);
+	line6_dumpreq_destructbuf(&variax->dumpreq, 1);
+	line6_dumpreq_destruct(&variax->dumpreq);
+
+	if(variax->buffer_activate) kfree(variax->buffer_activate);
+	del_timer_sync(&variax->activate_timer);
+}
+
+/*
+	Create sysfs entries.
+*/
+int variax_create_files2(struct device *dev)
+{
+	int err;
+	CHECK_RETURN(device_create_file(dev, &dev_attr_model));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_volume));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_tone));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_name));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_bank));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_dump));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_active));
+#if CREATE_RAW_FILE
+	CHECK_RETURN(device_create_file(dev, &dev_attr_raw));
+	CHECK_RETURN(device_create_file(dev, &dev_attr_raw2));
+#endif
+	return 0;
+}
+
+/*
+	 Init workbench device.
+*/
+int variax_init(struct usb_interface *interface, struct usb_line6_variax *variax)
+{
+	int err;
+
+	if((interface == NULL) || (variax == NULL)) return -ENODEV;
+
+	/* initialize USB buffers: */
+	err = line6_dumpreq_init(&variax->dumpreq, variax_request_model1, sizeof(variax_request_model1));
+
+	if(err < 0) {
+		dev_err(&interface->dev, "Out of memory\n");
+		variax_destruct(interface);
+		return err;
+	}
+
+	err = line6_dumpreq_initbuf(&variax->dumpreq, variax_request_model2, sizeof(variax_request_model2), 1);
+
+	if(err < 0) {
+		dev_err(&interface->dev, "Out of memory\n");
+		variax_destruct(interface);
+		return err;
+	}
+
+	err = line6_dumpreq_initbuf(&variax->dumpreq, variax_request_bank, sizeof(variax_request_bank), 2);
+
+	if(err < 0) {
+		dev_err(&interface->dev, "Out of memory\n");
+		variax_destruct(interface);
+		return err;
+	}
+
+	variax->buffer_activate = kmalloc(sizeof(variax_activate), GFP_KERNEL);
+
+	if(variax->buffer_activate == NULL) {
+		dev_err(&interface->dev, "Out of memory\n");
+		variax_destruct(interface);
+		return -ENOMEM;
+	}
+
+	memcpy(variax->buffer_activate, variax_activate, sizeof(variax_activate));
+	init_timer(&variax->activate_timer);
+
+	/* create sysfs entries: */
+	if((err = variax_create_files(0, 0, &interface->dev)) < 0) {
+		variax_destruct(interface);
+		return err;
+	}
+
+	if((err =	variax_create_files2(&interface->dev)) < 0) {
+		variax_destruct(interface);
+		return err;
+	}
+
+	/* initialize audio system: */
+	if((err = line6_init_audio(&variax->line6)) < 0) {
+		variax_destruct(interface);
+		return err;
+	}
+
+	/* initialize MIDI subsystem: */
+	if((err = line6_init_midi(&variax->line6)) < 0) {
+		variax_destruct(interface);
+		return err;
+	}
+
+	/* register audio system: */
+	if((err = line6_register_audio(&variax->line6)) < 0) {
+		variax_destruct(interface);
+		return err;
+	}
+
+	variax_activate_delayed(variax, VARIAX_ACTIVATE_DELAY);
+	line6_startup_delayed(&variax->dumpreq, VARIAX_STARTUP_DELAY, variax_startup_timeout, variax);
+	return 0;
+}
+
+/*
+	Workbench device disconnected.
+*/
+void variax_disconnect(struct usb_interface *interface)
+{
+	struct device *dev;
+
+	if(interface == NULL) return;
+	dev = &interface->dev;
+
+	if(dev != NULL) {
+		/* remove sysfs entries: */
+		variax_remove_files(0, 0, dev);
+		device_remove_file(dev, &dev_attr_model);
+		device_remove_file(dev, &dev_attr_volume);
+		device_remove_file(dev, &dev_attr_tone);
+		device_remove_file(dev, &dev_attr_name);
+		device_remove_file(dev, &dev_attr_bank);
+		device_remove_file(dev, &dev_attr_dump);
+		device_remove_file(dev, &dev_attr_active);
+#if CREATE_RAW_FILE
+		device_remove_file(dev, &dev_attr_raw);
+		device_remove_file(dev, &dev_attr_raw2);
+#endif
+	}
+
+	variax_destruct(interface);
+}