/*
 * Line 6 Linux USB driver
 *
 * Copyright (C) 2004-2010 Markus Grabner (grabner@icg.tugraz.at)
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License as
 *      published by the Free Software Foundation, version 2.
 *
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/usb.h>

#include <sound/core.h>
#include <sound/initval.h>

#include "capture.h"
#include "driver.h"
#include "midi.h"
#include "playback.h"

#define DRIVER_AUTHOR  "Markus Grabner <grabner@icg.tugraz.at>"
#define DRIVER_DESC    "Line 6 USB Driver"

/*
        This is Line 6's MIDI manufacturer ID.
*/
const unsigned char line6_midi_id[] = {
        0x00, 0x01, 0x0c
};
EXPORT_SYMBOL_GPL(line6_midi_id);

/*
        Code to request version of POD, Variax interface
        (and maybe other devices).
*/
static const char line6_request_version[] = {
        0xf0, 0x7e, 0x7f, 0x06, 0x01, 0xf7
};

/*
         Class for asynchronous messages.
*/
struct message {
        struct usb_line6 *line6;
        const char *buffer;
        int size;
        int done;
};

/*
        Forward declarations.
*/
static void line6_data_received(struct urb *urb);
static int line6_send_raw_message_async_part(struct message *msg,
                                             struct urb *urb);

/*
        Start to listen on endpoint.
*/
static int line6_start_listen(struct usb_line6 *line6)
{
        int err;

        usb_fill_int_urb(line6->urb_listen, line6->usbdev,
                usb_rcvintpipe(line6->usbdev, line6->properties->ep_ctrl_r),
                line6->buffer_listen, LINE6_BUFSIZE_LISTEN,
                line6_data_received, line6, line6->interval);
        line6->urb_listen->actual_length = 0;
        err = usb_submit_urb(line6->urb_listen, GFP_ATOMIC);
        return err;
}

/*
        Stop listening on endpoint.
*/
static void line6_stop_listen(struct usb_line6 *line6)
{
        usb_kill_urb(line6->urb_listen);
}

/*
        Send raw message in pieces of wMaxPacketSize bytes.
*/
static int line6_send_raw_message(struct usb_line6 *line6, const char *buffer,
                                  int size)
{
        int i, done = 0;

        for (i = 0; i < size; i += line6->max_packet_size) {
                int partial;
                const char *frag_buf = buffer + i;
                int frag_size = min(line6->max_packet_size, size - i);
                int retval;

                retval = usb_interrupt_msg(line6->usbdev,
                                        usb_sndintpipe(line6->usbdev,
                                                line6->properties->ep_ctrl_w),
                                        (char *)frag_buf, frag_size,
                                        &partial, LINE6_TIMEOUT * HZ);

                if (retval) {
                        dev_err(line6->ifcdev,
                                "usb_interrupt_msg failed (%d)\n", retval);
                        break;
                }

                done += frag_size;
        }

        return done;
}

/*
        Notification of completion of asynchronous request transmission.
*/
static void line6_async_request_sent(struct urb *urb)
{
        struct message *msg = (struct message *)urb->context;

        if (msg->done >= msg->size) {
                usb_free_urb(urb);
                kfree(msg);
        } else
                line6_send_raw_message_async_part(msg, urb);
}

/*
        Asynchronously send part of a raw message.
*/
static int line6_send_raw_message_async_part(struct message *msg,
                                             struct urb *urb)
{
        int retval;
        struct usb_line6 *line6 = msg->line6;
        int done = msg->done;
        int bytes = min(msg->size - done, line6->max_packet_size);

        usb_fill_int_urb(urb, line6->usbdev,
                usb_sndintpipe(line6->usbdev, line6->properties->ep_ctrl_w),
                (char *)msg->buffer + done, bytes,
                line6_async_request_sent, msg, line6->interval);

        msg->done += bytes;
        retval = usb_submit_urb(urb, GFP_ATOMIC);

        if (retval < 0) {
                dev_err(line6->ifcdev, "%s: usb_submit_urb failed (%d)\n",
                        __func__, retval);
                usb_free_urb(urb);
                kfree(msg);
                return retval;
        }

        return 0;
}

/*
        Setup and start timer.
*/
void line6_start_timer(struct timer_list *timer, unsigned long msecs,
                       void (*function)(unsigned long), unsigned long data)
{
        setup_timer(timer, function, data);
        mod_timer(timer, jiffies + msecs_to_jiffies(msecs));
}
EXPORT_SYMBOL_GPL(line6_start_timer);

/*
        Asynchronously send raw message.
*/
int line6_send_raw_message_async(struct usb_line6 *line6, const char *buffer,
                                 int size)
{
        struct message *msg;
        struct urb *urb;

        /* create message: */
        msg = kmalloc(sizeof(struct message), GFP_ATOMIC);
        if (msg == NULL)
                return -ENOMEM;

        /* create URB: */
        urb = usb_alloc_urb(0, GFP_ATOMIC);

        if (urb == NULL) {
                kfree(msg);
                return -ENOMEM;
        }

        /* set message data: */
        msg->line6 = line6;
        msg->buffer = buffer;
        msg->size = size;
        msg->done = 0;

        /* start sending: */
        return line6_send_raw_message_async_part(msg, urb);
}
EXPORT_SYMBOL_GPL(line6_send_raw_message_async);

/*
        Send asynchronous device version request.
*/
int line6_version_request_async(struct usb_line6 *line6)
{
        char *buffer;
        int retval;

        buffer = kmemdup(line6_request_version,
                        sizeof(line6_request_version), GFP_ATOMIC);
        if (buffer == NULL)
                return -ENOMEM;

        retval = line6_send_raw_message_async(line6, buffer,
                                              sizeof(line6_request_version));
        kfree(buffer);
        return retval;
}
EXPORT_SYMBOL_GPL(line6_version_request_async);

/*
        Send sysex message in pieces of wMaxPacketSize bytes.
*/
int line6_send_sysex_message(struct usb_line6 *line6, const char *buffer,
                             int size)
{
        return line6_send_raw_message(line6, buffer,
                                      size + SYSEX_EXTRA_SIZE) -
            SYSEX_EXTRA_SIZE;
}
EXPORT_SYMBOL_GPL(line6_send_sysex_message);

/*
        Allocate buffer for sysex message and prepare header.
        @param code sysex message code
        @param size number of bytes between code and sysex end
*/
char *line6_alloc_sysex_buffer(struct usb_line6 *line6, int code1, int code2,
                               int size)
{
        char *buffer = kmalloc(size + SYSEX_EXTRA_SIZE, GFP_ATOMIC);

        if (!buffer)
                return NULL;

        buffer[0] = LINE6_SYSEX_BEGIN;
        memcpy(buffer + 1, line6_midi_id, sizeof(line6_midi_id));
        buffer[sizeof(line6_midi_id) + 1] = code1;
        buffer[sizeof(line6_midi_id) + 2] = code2;
        buffer[sizeof(line6_midi_id) + 3 + size] = LINE6_SYSEX_END;
        return buffer;
}
EXPORT_SYMBOL_GPL(line6_alloc_sysex_buffer);

/*
        Notification of data received from the Line 6 device.
*/
static void line6_data_received(struct urb *urb)
{
        struct usb_line6 *line6 = (struct usb_line6 *)urb->context;
        struct midi_buffer *mb = &line6->line6midi->midibuf_in;
        int done;

        if (urb->status == -ESHUTDOWN)
                return;

        done =
            line6_midibuf_write(mb, urb->transfer_buffer, urb->actual_length);

        if (done < urb->actual_length) {
                line6_midibuf_ignore(mb, done);
                dev_dbg(line6->ifcdev, "%d %d buffer overflow - message skipped\n",
                        done, urb->actual_length);
        }

        for (;;) {
                done =
                    line6_midibuf_read(mb, line6->buffer_message,
                                       LINE6_MESSAGE_MAXLEN);

                if (done == 0)
                        break;

                line6->message_length = done;
                line6_midi_receive(line6, line6->buffer_message, done);

                if (line6->process_message)
                        line6->process_message(line6);
        }

        line6_start_listen(line6);
}

#define LINE6_READ_WRITE_STATUS_DELAY 2  /* milliseconds */
#define LINE6_READ_WRITE_MAX_RETRIES 50

/*
        Read data from device.
*/
int line6_read_data(struct usb_line6 *line6, unsigned address, void *data,
                    unsigned datalen)
{
        struct usb_device *usbdev = line6->usbdev;
        int ret;
        unsigned char len;
        unsigned count;

        if (address > 0xffff || datalen > 0xff)
                return -EINVAL;

        /* query the serial number: */
        ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
                              USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
                              (datalen << 8) | 0x21, address,
                              NULL, 0, LINE6_TIMEOUT * HZ);

        if (ret < 0) {
                dev_err(line6->ifcdev, "read request failed (error %d)\n", ret);
                return ret;
        }

        /* Wait for data length. We'll get 0xff until length arrives. */
        for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
                mdelay(LINE6_READ_WRITE_STATUS_DELAY);

                ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
                                      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
                                      USB_DIR_IN,
                                      0x0012, 0x0000, &len, 1,
                                      LINE6_TIMEOUT * HZ);
                if (ret < 0) {
                        dev_err(line6->ifcdev,
                                "receive length failed (error %d)\n", ret);
                        return ret;
                }

                if (len != 0xff)
                        break;
        }

        if (len == 0xff) {
                dev_err(line6->ifcdev, "read failed after %d retries\n",
                        count);
                return -EIO;
        } else if (len != datalen) {
                /* should be equal or something went wrong */
                dev_err(line6->ifcdev,
                        "length mismatch (expected %d, got %d)\n",
                        (int)datalen, (int)len);
                return -EIO;
        }

        /* receive the result: */
        ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
                              USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_IN,
                              0x0013, 0x0000, data, datalen,
                              LINE6_TIMEOUT * HZ);

        if (ret < 0) {
                dev_err(line6->ifcdev, "read failed (error %d)\n", ret);
                return ret;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(line6_read_data);

/*
        Write data to device.
*/
int line6_write_data(struct usb_line6 *line6, unsigned address, void *data,
                     unsigned datalen)
{
        struct usb_device *usbdev = line6->usbdev;
        int ret;
        unsigned char status;
        int count;

        if (address > 0xffff || datalen > 0xffff)
                return -EINVAL;

        ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
                              USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
                              0x0022, address, data, datalen,
                              LINE6_TIMEOUT * HZ);

        if (ret < 0) {
                dev_err(line6->ifcdev,
                        "write request failed (error %d)\n", ret);
                return ret;
        }

        for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
                mdelay(LINE6_READ_WRITE_STATUS_DELAY);

                ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
                                      0x67,
                                      USB_TYPE_VENDOR | USB_RECIP_DEVICE |
                                      USB_DIR_IN,
                                      0x0012, 0x0000,
                                      &status, 1, LINE6_TIMEOUT * HZ);

                if (ret < 0) {
                        dev_err(line6->ifcdev,
                                "receiving status failed (error %d)\n", ret);
                        return ret;
                }

                if (status != 0xff)
                        break;
        }

        if (status == 0xff) {
                dev_err(line6->ifcdev, "write failed after %d retries\n",
                        count);
                return -EIO;
        } else if (status != 0) {
                dev_err(line6->ifcdev, "write failed (error %d)\n", ret);
                return -EIO;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(line6_write_data);

/*
        Read Line 6 device serial number.
        (POD, TonePort, GuitarPort)
*/
int line6_read_serial_number(struct usb_line6 *line6, u32 *serial_number)
{
        return line6_read_data(line6, 0x80d0, serial_number,
                               sizeof(*serial_number));
}
EXPORT_SYMBOL_GPL(line6_read_serial_number);

/*
        Card destructor.
*/
static void line6_destruct(struct snd_card *card)
{
        struct usb_line6 *line6 = card->private_data;
        struct usb_device *usbdev = line6->usbdev;

        /* free buffer memory first: */
        kfree(line6->buffer_message);
        kfree(line6->buffer_listen);

        /* then free URBs: */
        usb_free_urb(line6->urb_listen);

        /* decrement reference counters: */
        usb_put_dev(usbdev);
}

/* get data from endpoint descriptor (see usb_maxpacket): */
static void line6_get_interval(struct usb_line6 *line6)
{
        struct usb_device *usbdev = line6->usbdev;
        struct usb_host_endpoint *ep;
        unsigned pipe = usb_rcvintpipe(usbdev, line6->properties->ep_ctrl_r);
        unsigned epnum = usb_pipeendpoint(pipe);

        ep = usbdev->ep_in[epnum];
        if (ep) {
                line6->interval = ep->desc.bInterval;
                line6->max_packet_size = le16_to_cpu(ep->desc.wMaxPacketSize);
        } else {
                dev_err(line6->ifcdev,
                        "endpoint not available, using fallback values");
                line6->interval = LINE6_FALLBACK_INTERVAL;
                line6->max_packet_size = LINE6_FALLBACK_MAXPACKETSIZE;
        }
}

static int line6_init_cap_control(struct usb_line6 *line6)
{
        int ret;

        /* initialize USB buffers: */
        line6->buffer_listen = kmalloc(LINE6_BUFSIZE_LISTEN, GFP_KERNEL);
        if (!line6->buffer_listen)
                return -ENOMEM;

        line6->buffer_message = kmalloc(LINE6_MESSAGE_MAXLEN, GFP_KERNEL);
        if (!line6->buffer_message)
                return -ENOMEM;

        line6->urb_listen = usb_alloc_urb(0, GFP_KERNEL);
        if (!line6->urb_listen)
                return -ENOMEM;

        ret = line6_start_listen(line6);
        if (ret < 0) {
                dev_err(line6->ifcdev, "cannot start listening: %d\n", ret);
                return ret;
        }

        return 0;
}

/*
        Probe USB device.
*/
int line6_probe(struct usb_interface *interface,
                const struct usb_device_id *id,
                const char *driver_name,
                const struct line6_properties *properties,
                int (*private_init)(struct usb_line6 *, const struct usb_device_id *id),
                size_t data_size)
{
        struct usb_device *usbdev = interface_to_usbdev(interface);
        struct snd_card *card;
        struct usb_line6 *line6;
        int interface_number;
        int ret;

        if (WARN_ON(data_size < sizeof(*line6)))
                return -EINVAL;

        /* we don't handle multiple configurations */
        if (usbdev->descriptor.bNumConfigurations != 1)
                return -ENODEV;

        ret = snd_card_new(&interface->dev,
                           SNDRV_DEFAULT_IDX1, SNDRV_DEFAULT_STR1,
                           THIS_MODULE, data_size, &card);
        if (ret < 0)
                return ret;

        /* store basic data: */
        line6 = card->private_data;
        line6->card = card;
        line6->properties = properties;
        line6->usbdev = usbdev;
        line6->ifcdev = &interface->dev;

        strcpy(card->id, properties->id);
        strcpy(card->driver, driver_name);
        strcpy(card->shortname, properties->name);
        sprintf(card->longname, "Line 6 %s at USB %s", properties->name,
                dev_name(line6->ifcdev));
        card->private_free = line6_destruct;

        usb_set_intfdata(interface, line6);

        /* increment reference counters: */
        usb_get_dev(usbdev);

        /* initialize device info: */
        dev_info(&interface->dev, "Line 6 %s found\n", properties->name);

        /* query interface number */
        interface_number = interface->cur_altsetting->desc.bInterfaceNumber;

        ret = usb_set_interface(usbdev, interface_number,
                                properties->altsetting);
        if (ret < 0) {
                dev_err(&interface->dev, "set_interface failed\n");
                goto error;
        }

        line6_get_interval(line6);

        if (properties->capabilities & LINE6_CAP_CONTROL) {
                ret = line6_init_cap_control(line6);
                if (ret < 0)
                        goto error;
        }

        /* initialize device data based on device: */
        ret = private_init(line6, id);
        if (ret < 0)
                goto error;

        /* creation of additional special files should go here */

        dev_info(&interface->dev, "Line 6 %s now attached\n",
                 properties->name);

        return 0;

 error:
        if (line6->disconnect)
                line6->disconnect(line6);
        snd_card_free(card);
        return ret;
}
EXPORT_SYMBOL_GPL(line6_probe);

/*
        Line 6 device disconnected.
*/
void line6_disconnect(struct usb_interface *interface)
{
        struct usb_line6 *line6 = usb_get_intfdata(interface);
        struct usb_device *usbdev = interface_to_usbdev(interface);

        if (!line6)
                return;

        if (WARN_ON(usbdev != line6->usbdev))
                return;

        if (line6->urb_listen != NULL)
                line6_stop_listen(line6);

        snd_card_disconnect(line6->card);
        if (line6->line6pcm)
                line6_pcm_disconnect(line6->line6pcm);
        if (line6->disconnect)
                line6->disconnect(line6);

        dev_info(&interface->dev, "Line 6 %s now disconnected\n",
                 line6->properties->name);

        /* make sure the device isn't destructed twice: */
        usb_set_intfdata(interface, NULL);

        snd_card_free_when_closed(line6->card);
}
EXPORT_SYMBOL_GPL(line6_disconnect);

#ifdef CONFIG_PM

/*
        Suspend Line 6 device.
*/
int line6_suspend(struct usb_interface *interface, pm_message_t message)
{
        struct usb_line6 *line6 = usb_get_intfdata(interface);
        struct snd_line6_pcm *line6pcm = line6->line6pcm;

        snd_power_change_state(line6->card, SNDRV_CTL_POWER_D3hot);

        if (line6->properties->capabilities & LINE6_CAP_CONTROL)
                line6_stop_listen(line6);

        if (line6pcm != NULL) {
                snd_pcm_suspend_all(line6pcm->pcm);
                line6pcm->flags = 0;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(line6_suspend);

/*
        Resume Line 6 device.
*/
int line6_resume(struct usb_interface *interface)
{
        struct usb_line6 *line6 = usb_get_intfdata(interface);

        if (line6->properties->capabilities & LINE6_CAP_CONTROL)
                line6_start_listen(line6);

        snd_power_change_state(line6->card, SNDRV_CTL_POWER_D0);
        return 0;
}
EXPORT_SYMBOL_GPL(line6_resume);

#endif /* CONFIG_PM */

MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");