Fireface 802 was shipped by RME GmbH in 2014. This model supports later
protocol for management of isochronous communication and synchronization
of sampling transmission frequency.

This model consists of below ICs:
 * TI TSB41AB2
 * Xilinx Spartan-6 FPGA XC6SLX16
 * TI TMS320 C6747
 * SMSC USB3250

Especially, this model just supports IEEE 1394a, against its name which
evokes Fireface 800.

This commit adds support for Fireface 802 (tested). Userspace applications
can transfer PCM frames and MIDI messages via ALSA PCM/Rawmidi interface.
I note that 4 channels for ADAt1 and ADAT2 are disabled at higher sampling
transfer frequency since isochronous resources reservation fails due to
bandwidth limitation of IEEE 1394a.

The value read from LATTER_SYNC_STATUS register is slightly different
from the one of Fireface UCX. The higher 4 bits and lower 4 bits are
swapped within the same byte.

Without any assist of userspace application, transmitted MIDI messages
from the device are not going to be processed. For detail, please refer
to my comment in code of latter protocol.

$ python crpp < /sys/bus/firewire/devices/fw1/config_rom
               ROM header and bus information block
               -----------------------------------------------------------------
400  0404ffff  bus_info_length 4, crc_length 4, crc 65535 (should be 26805)
404  31333934  bus_name "1394"
408  20008000  irmc 0, cmc 0, isc 1, bmc 0, cyc_clk_acc 0, max_rec 8 (512)
40c  000a3504  company_id 000a35     |
410  38077423  device_id 0438077423  | EUI-64 000a350438077423

               root directory
               -----------------------------------------------------------------
414  0005ffff  directory_length 5, crc 65535 (should be 9514)
418  0c0083c0  node capabilities per IEEE 1394
41c  03000a35  vendor
420  8100000b  --> descriptor leaf at 44c
424  8d000007  --> eui-64 leaf at 440
428  d1000001  --> unit directory at 42c

               unit directory at 42c
               -----------------------------------------------------------------
42c  0004ffff  directory_length 4, crc 65535 (should be 45134)
430  12000a35  specifier id
434  13000005  version
438  17101800  model
43c  81000008  --> descriptor leaf at 45c

               eui-64 leaf at 440
               -----------------------------------------------------------------
440  0002ffff  leaf_length 2, crc 65535 (should be 60131)
444  000a3504  company_id 000a35     |
448  38077423  device_id 0438077423  | EUI-64 000a350438077423

               descriptor leaf at 44c
               -----------------------------------------------------------------
44c  0003ffff  leaf_length 3, crc 65535 (should be 469)
450  00000000  textual descriptor
454  00000000  minimal ASCII
458  524d4521  "RME!"

               descriptor leaf at 45c
               -----------------------------------------------------------------
45c  0005ffff  leaf_length 5, crc 65535 (should be 10561)
460  00000000  textual descriptor
464  00000000  minimal ASCII
468  46697265  "Fire"
46c  66616365  "face"
470  20383032  " 802"
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Link: https://lore.kernel.org/r/20200510074301.116224-6-o-takashi@sakamocchi.jpSigned-off-by: Takashi Iwai <tiwai@suse.de>