auerswald.c

linux-2.6.15.6

/* Values of urb->status or results of usb_submit_urb():
0		Initial, OK
-EINPROGRESS	during submission until end
-ENOENT		if urb is unlinked
-ETIMEDOUT	Transfer timed out, NAK
-ENOMEM		Memory Overflow
-ENODEV		Specified USB-device or bus doesn't exist
-ENXIO		URB already queued
-EINVAL		a) Invalid transfer type specified (or not supported)
		b) Invalid interrupt interval (0n256)
-EAGAIN		a) Specified ISO start frame too early
		b) (using ISO-ASAP) Too much scheduled for the future wait some time and try again.
-EFBIG		Too much ISO frames requested (currently uhci900)
-EPIPE		Specified pipe-handle/Endpoint is already stalled
-EMSGSIZE	Endpoint message size is zero, do interface/alternate setting
-EPROTO		a) Bitstuff error
		b) Unknown USB error
-EILSEQ		CRC mismatch
-ENOSR		Buffer error
-EREMOTEIO	Short packet detected
-EXDEV		ISO transfer only partially completed look at individual frame status for details
-EINVAL		ISO madness, if this happens: Log off and go home
-EOVERFLOW	babble
*/

/* check if a status code allows a retry */
static int auerswald_status_retry (int status)
{
	switch (status) {
	case 0:
	case -ETIMEDOUT:
	case -EOVERFLOW:
	case -EAGAIN:
	case -EPIPE:
	case -EPROTO:
	case -EILSEQ:
	case -ENOSR:
	case -EREMOTEIO:
		return 1; /* do a retry */
	}
	return 0;	/* no retry possible */
}

/* Completion of asynchronous write block */
static void auerchar_ctrlwrite_complete (struct urb * urb, struct pt_regs *regs)
{
	pauerbuf_t bp = (pauerbuf_t) urb->context;
	pauerswald_t cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));
	dbg ("auerchar_ctrlwrite_complete called");

	/* reuse the buffer */
	auerbuf_releasebuf (bp);
	/* Wake up all processes waiting for a buffer */
	wake_up (&cp->bufferwait);
}

/* Completion handler for dummy retry packet */
static void auerswald_ctrlread_wretcomplete (struct urb * urb, struct pt_regs *regs)
{
        pauerbuf_t bp = (pauerbuf_t) urb->context;
        pauerswald_t cp;
	int ret;
        dbg ("auerswald_ctrlread_wretcomplete called");
        dbg ("complete with status: %d", urb->status);
	cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));

	/* check if it is possible to advance */
	if (!auerswald_status_retry (urb->status) || !cp->usbdev) {
		/* reuse the buffer */
		err ("control dummy: transmission error %d, can not retry", urb->status);
		auerbuf_releasebuf (bp);
		/* Wake up all processes waiting for a buffer */
		wake_up (&cp->bufferwait);
		return;
	}

	/* fill the control message */
	bp->dr->bRequestType = AUT_RREQ;
	bp->dr->bRequest     = AUV_RBLOCK;
	bp->dr->wLength      = bp->dr->wValue;	/* temporary stored */
	bp->dr->wValue       = cpu_to_le16 (1);	/* Retry Flag */
	/* bp->dr->index    = channel id;          remains */
	usb_fill_control_urb (bp->urbp, cp->usbdev, usb_rcvctrlpipe (cp->usbdev, 0),
                          (unsigned char*)bp->dr, bp->bufp, le16_to_cpu (bp->dr->wLength),
		          auerswald_ctrlread_complete,bp);

	/* submit the control msg as next paket */
	ret = auerchain_submit_urb_list (&cp->controlchain, bp->urbp, 1);
        if (ret) {
        	dbg ("auerswald_ctrlread_complete: nonzero result of auerchain_submit_urb_list %d", ret);
        	bp->urbp->status = ret;
        	auerswald_ctrlread_complete (bp->urbp, NULL);
    	}
}

/* completion handler for receiving of control messages */
static void auerswald_ctrlread_complete (struct urb * urb, struct pt_regs *regs)
{
        unsigned int  serviceid;
        pauerswald_t  cp;
        pauerscon_t   scp;
        pauerbuf_t    bp  = (pauerbuf_t) urb->context;
	int ret;
        dbg ("auerswald_ctrlread_complete called");

	cp = ((pauerswald_t)((char *)(bp->list)-(unsigned long)(&((pauerswald_t)0)->bufctl)));

	/* check if there is valid data in this urb */
        if (urb->status) {
		dbg ("complete with non-zero status: %d", urb->status);
		/* should we do a retry? */
		if (!auerswald_status_retry (urb->status)
		 || !cp->usbdev
		 || (cp->version < AUV_RETRY)
                 || (bp->retries >= AU_RETRIES)) {
			/* reuse the buffer */
			err ("control read: transmission error %d, can not retry", urb->status);
			auerbuf_releasebuf (bp);
			/* Wake up all processes waiting for a buffer */
			wake_up (&cp->bufferwait);
			return;
		}
		bp->retries++;
		dbg ("Retry count = %d", bp->retries);
		/* send a long dummy control-write-message to allow device firmware to react */
		bp->dr->bRequestType = AUT_WREQ;
		bp->dr->bRequest     = AUV_DUMMY;
		bp->dr->wValue       = bp->dr->wLength; /* temporary storage */
		// bp->dr->wIndex    channel ID remains
		bp->dr->wLength      = cpu_to_le16 (32); /* >= 8 bytes */
		usb_fill_control_urb (bp->urbp, cp->usbdev, usb_sndctrlpipe (cp->usbdev, 0),
  			(unsigned char*)bp->dr, bp->bufp, 32,
	   		auerswald_ctrlread_wretcomplete,bp);

		/* submit the control msg as next paket */
       		ret = auerchain_submit_urb_list (&cp->controlchain, bp->urbp, 1);
       		if (ret) {
               		dbg ("auerswald_ctrlread_complete: nonzero result of auerchain_submit_urb_list %d", ret);
               		bp->urbp->status = ret;
               		auerswald_ctrlread_wretcomplete (bp->urbp, regs);
		}
                return;
        }

        /* get the actual bytecount (incl. headerbyte) */
        bp->len = urb->actual_length;
        serviceid = bp->bufp[0] & AUH_TYPEMASK;
        dbg ("Paket with serviceid %d and %d bytes received", serviceid, bp->len);

        /* dispatch the paket */
        scp = cp->services[serviceid];
        if (scp) {
                /* look, Ma, a listener! */
                scp->dispatch (scp, bp);
        }

        /* release the paket */
        auerbuf_releasebuf (bp);
	/* Wake up all processes waiting for a buffer */
	wake_up (&cp->bufferwait);
}

/*-------------------------------------------------------------------*/
/* Handling of Interrupt Endpoint                                    */
/* This interrupt Endpoint is used to inform the host about waiting
   messages from the USB device.
*/
/* int completion handler. */
static void auerswald_int_complete (struct urb * urb, struct pt_regs *regs)
{
        unsigned long flags;
        unsigned  int channelid;
        unsigned  int bytecount;
        int ret;
        pauerbuf_t   bp = NULL;
        pauerswald_t cp = (pauerswald_t) urb->context;

        dbg ("%s called", __FUNCTION__);

	switch (urb->status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dbg("%s - urb shutting down with status: %d", __FUNCTION__, urb->status);
		return;
	default:
		dbg("%s - nonzero urb status received: %d", __FUNCTION__, urb->status);
		goto exit;
	}

        /* check if all needed data was received */
	if (urb->actual_length < AU_IRQMINSIZE) {
                dbg ("invalid data length received: %d bytes", urb->actual_length);
		goto exit;
        }

        /* check the command code */
        if (cp->intbufp[0] != AU_IRQCMDID) {
                dbg ("invalid command received: %d", cp->intbufp[0]);
		goto exit;
        }

        /* check the command type */
        if (cp->intbufp[1] != AU_BLOCKRDY) {
                dbg ("invalid command type received: %d", cp->intbufp[1]);
		goto exit;
        }

        /* now extract the information */
        channelid = cp->intbufp[2];
        bytecount = (unsigned char)cp->intbufp[3];
        bytecount |= (unsigned char)cp->intbufp[4] << 8;

        /* check the channel id */
        if (channelid >= AUH_TYPESIZE) {
                dbg ("invalid channel id received: %d", channelid);
		goto exit;
        }

        /* check the byte count */
        if (bytecount > (cp->maxControlLength+AUH_SIZE)) {
                dbg ("invalid byte count received: %d", bytecount);
		goto exit;
        }
        dbg ("Service Channel = %d", channelid);
        dbg ("Byte Count = %d", bytecount);

        /* get a buffer for the next data paket */
        spin_lock_irqsave (&cp->bufctl.lock, flags);
        if (!list_empty (&cp->bufctl.free_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = cp->bufctl.free_buff_list.next;
                list_del (tmp);
                bp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&cp->bufctl.lock, flags);

        /* if no buffer available: skip it */
        if (!bp) {
                dbg ("auerswald_int_complete: no data buffer available");
                /* can we do something more?
		   This is a big problem: if this int packet is ignored, the
		   device will wait forever and not signal any more data.
		   The only real solution is: having enough buffers!
		   Or perhaps temporary disabling the int endpoint?
		*/
		goto exit;
        }

	/* fill the control message */
        bp->dr->bRequestType = AUT_RREQ;
	bp->dr->bRequest     = AUV_RBLOCK;
	bp->dr->wValue       = cpu_to_le16 (0);
	bp->dr->wIndex       = cpu_to_le16 (channelid | AUH_DIRECT | AUH_UNSPLIT);
	bp->dr->wLength      = cpu_to_le16 (bytecount);
	usb_fill_control_urb (bp->urbp, cp->usbdev, usb_rcvctrlpipe (cp->usbdev, 0),
                          (unsigned char*)bp->dr, bp->bufp, bytecount,
		          auerswald_ctrlread_complete,bp);

        /* submit the control msg */
        ret = auerchain_submit_urb (&cp->controlchain, bp->urbp);
        if (ret) {
                dbg ("auerswald_int_complete: nonzero result of auerchain_submit_urb %d", ret);
                bp->urbp->status = ret;
                auerswald_ctrlread_complete( bp->urbp, NULL);
		/* here applies the same problem as above: device locking! */
        }
exit:
	ret = usb_submit_urb (urb, GFP_ATOMIC);
	if (ret)
		err ("%s - usb_submit_urb failed with result %d",
		     __FUNCTION__, ret);
}

/* int memory deallocation
   NOTE: no mutex please!
*/
static void auerswald_int_free (pauerswald_t cp)
{
	if (cp->inturbp) {
		usb_free_urb(cp->inturbp);
		cp->inturbp = NULL;
	}
	kfree(cp->intbufp);
	cp->intbufp = NULL;
}

/* This function is called to activate the interrupt
   endpoint. This function returns 0 if successful or an error code.
   NOTE: no mutex please!
*/
static int auerswald_int_open (pauerswald_t cp)
{
        int ret;
	struct usb_host_endpoint *ep;
	int irqsize;
	dbg ("auerswald_int_open");

	ep = cp->usbdev->ep_in[AU_IRQENDP];
	if (!ep) {
		ret = -EFAULT;
  		goto intoend;
    	}
	irqsize = le16_to_cpu(ep->desc.wMaxPacketSize);
	cp->irqsize = irqsize;

	/* allocate the urb and data buffer */
        if (!cp->inturbp) {
                cp->inturbp = usb_alloc_urb (0, GFP_KERNEL);
                if (!cp->inturbp) {
                        ret = -ENOMEM;
                        goto intoend;
                }
        }
        if (!cp->intbufp) {
                cp->intbufp = (char *) kmalloc (irqsize, GFP_KERNEL);
                if (!cp->intbufp) {
                        ret = -ENOMEM;
                        goto intoend;
                }
        }
        /* setup urb */
        usb_fill_int_urb (cp->inturbp, cp->usbdev,
			usb_rcvintpipe (cp->usbdev,AU_IRQENDP), cp->intbufp,
			irqsize, auerswald_int_complete, cp, ep->desc.bInterval);
        /* start the urb */
	cp->inturbp->status = 0;	/* needed! */
	ret = usb_submit_urb (cp->inturbp, GFP_KERNEL);

intoend:
        if (ret < 0) {
                /* activation of interrupt endpoint has failed. Now clean up. */
                dbg ("auerswald_int_open: activation of int endpoint failed");

                /* deallocate memory */
                auerswald_int_free (cp);
        }
        return ret;
}

/* This function is called to deactivate the interrupt
   endpoint. This function returns 0 if successful or an error code.
   NOTE: no mutex please!
*/
static void auerswald_int_release (pauerswald_t cp)
{
        dbg ("auerswald_int_release");

        /* stop the int endpoint */
        if (cp->inturbp)
                usb_kill_urb (cp->inturbp);

        /* deallocate memory */
        auerswald_int_free (cp);
}

/* --------------------------------------------------------------------- */
/* Helper functions                                                      */

/* wake up waiting readers */
static void auerchar_disconnect (pauerscon_t scp)
{
        pauerchar_t ccp = ((pauerchar_t)((char *)(scp)-(unsigned long)(&((pauerchar_t)0)->scontext)));
	dbg ("auerchar_disconnect called");
	ccp->removed = 1;
	wake_up (&ccp->readwait);
}


/* dispatch a read paket to a waiting character device */
static void auerchar_ctrlread_dispatch (pauerscon_t scp, pauerbuf_t bp)
{
	unsigned long flags;
        pauerchar_t ccp;
        pauerbuf_t newbp = NULL;
        char * charp;
        dbg ("auerchar_ctrlread_dispatch called");
        ccp = ((pauerchar_t)((char *)(scp)-(unsigned long)(&((pauerchar_t)0)->scontext)));

        /* get a read buffer from character device context */
        spin_lock_irqsave (&ccp->bufctl.lock, flags);
        if (!list_empty (&ccp->bufctl.free_buff_list)) {
                /* yes: get the entry */
                struct list_head *tmp = ccp->bufctl.free_buff_list.next;
                list_del (tmp);
                newbp = list_entry (tmp, auerbuf_t, buff_list);
        }
        spin_unlock_irqrestore (&ccp->bufctl.lock, flags);

        if (!newbp) {
                dbg ("No read buffer available, discard paket!");
                return;     /* no buffer, no dispatch */
        }

        /* copy information to new buffer element
           (all buffers have the same length) */
        charp = newbp->bufp;
        newbp->bufp = bp->bufp;
        bp->bufp = charp;