comm.c

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/*
 * Linux driver for TerraTec DMX 6Fire USB
 *
 * Device communications
 *
 * Author:  Torsten Schenk <[email protected]>
 * Created: Jan 01, 2011
 * 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;
}