Add instructions to build on Ubuntu
Add Avalon2 (2U size machine) support

Signed-off-by: Xiangfu <xiangfu@openmobilefree.net>
Initial import of Bitmine.ch A1 SPI driver

This initial driver was designed around an FPGA based
emulator board which provides 2 chained chips with 4
hashing engines each, running at 10% of the A1's
nominal speed.

Driver has been tested on RasPi.

Signed-off-by: Zefir Kurtisi <zefir.kurtisi@gmail.com>
A1: CoinCraft-Desk driver variant

The CoinCraft-Desk product includes up to 5 8-chip modules
that are accessed over a TCA9539 IO multiplexer.

This is the initial support for the CCD.
Store the maximum board temperature for hfa devices and take that into consideration when calculating the highest temperature as well as the dies.
Merge branch 'master' of github.com:ckolivas/cgminer
Store the hfa hash_clock rate and display it in the statline.
Send a work restart with every shutdown message to hfa devices to clear any work that might be stale on the next restart.
Put MHz into cta statline description.
Check return result of hfa clear readbuf to minimise error messages on device failure.
Hfa device failure can be detected within 15 seconds so we should try restarting it sooner to avoid tripping the device's own watchdog.
Set the per die clock on hfa to the known starting base clock instead of our requested clock rate.
Update the per die hash clock data on a running reset on hfa devices.
bab - roll work if possible to reduce CPU
bab - use 'bad' instead of 'dead' as per the screen B:
Merge pull request #552 from kanoi/master

bab - roll work if possible to reduce CPU + dead->bad
bab - missed a few 'DEAD's in last commit
Merge pull request #553 from kanoi/master

bab - missed a few 'DEAD's in last commit
Merge pull request #551 from bitmine-ch/upstream.CCD

Upstream.ccd
Move bitmine options to alphabetic positioning.