Currently ALSA dice driver handles a pair of isochronous resources for
IEC 61883-1/6 packet streaming. While, according to some documents about
ASICs named as 'Dice', several isochronous streams are available.

Here, I start to describe ASICs produced under 'Dice' name.
 * Dice II (designed by wavefront semiconductor, including TCAT's IP)
   * STD (with limited functionality of DTCP)
   * CP  (with full functionality of DTCP)
 * TCD2210/2210-E (so-called 'Dice Mini')
 * TCD2220/2220-E (so-called 'Dice Jr.')
 * TCD3070-CH (so-called 'Dice III')

Some documents are public and we can see hardware design of them. We can
find some articles about hardware internal register definitions
(not registers exported to IEEE 1394 bus).

* DICE II User Guide
  * http://www.tctechnologies.tc/archive/downloads/dice_ii_user_guide.pdf
    * 6.1 AVS Audio Receivers
      * Table 6.1: AVS Audio Receiver Memory Map
        * ARX1-ARX4
    * 6.2 AVS Audio Transmitters
      * Table 6.2: AVS Audio Transmitter Memory Map
        * ATX1, ATX2
* TCD22xx User Guide
  * http://www.tctechnologies.tc/downloads/tcd22xx_user_guide.pdf
    * 6.1 AVS Audio Receivers
      * Table 66: AVS Audio Receiver Memory Map
        * ARX1, ARX2
    * 6/2 AVS Audio Transmitters
      * Table 67: AVS Audio Transmitter Memory Map
        * ATX1, ATX2
* DICE III
  * http://www.tctechnologies.tc/downloads/TCD3070-CH.pdf
    * Dual stream 63 channel transmitter/receiver

For Dice II and TCD22xx series, maximum 16 data channels are transferred in
an AMDTP packet, while for Dice III, maximum 32 data channels are
transferred.

According to the design of the series of these ASICs, this commit allows
this driver to handle additional set of isochronous resources. For
practical reason, two pair of isochronous resources are added. As of this
commit, this driver still use a pair of the first isochronous resources.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>