Commit Graph

3 Commits

Author SHA1 Message Date
gibbs
3e9f8a5d64 Revamp the way that exceptional message handling is performed so that it
is more robust and common code can be used for both the target and iniator
roles.  The mechanism for tracking negotiation state has also been simplified.

Add support for sync/wide negotiation in target mode and fix many of
the target mode bugs running at higher speeds uncovered.  Make a first
stab at getting all of the bus skew delays correct.  Sync+Wide dataout
transfers still cause problems, but this may be an initiator problem.

Ensure that we exit BITBUCKET mode if the controller is restarted.

Add support for target mode only firmware downloads.  This has been
tested on the aic7880, but should mean that we can perform target mode
on any aic7xxx controller.  Mixed mode (initiator and target roles in
the same firmware load) is currently only supported on the aic7890, but
with optimization, may fit on chips with less instruction space.
1998-12-10 04:14:50 +00:00
gibbs
ad7080d581 Change the delivery mechanism for incoming target commands. We now
use a 256 entry ring buffer of descriptersfor this purpose.  This allows
the use of a simple 8bit counter in the sequencer code for tracking start
location.

Entries in the ring buffer now contain a "cmd_valid" byte at their tail.
As an entry is serviced, this byte is cleared by the kernel and set by
the sequencer during its dma of a new entry.  Since this byte is the last
portion of the command touched during a dma, the kernel can use this
byte to ensure the command it processes is completely valid.

The new command format requires a fixed sized DMA from the controller
to deliver which allowed for additional simplification of the sequencer
code.  The hack that required 1 SCB slot to be stolen for incoming
command delivery notification is also gone.
1998-11-23 01:33:47 +00:00
gibbs
b845ffee80 Massive overhaul of the aic7xxx driver:
- Convert to CAM
 - Use a new DMA based queuing and paging scheme
 - Add preliminary target mode support
 - Add support for the aic789X chips
 - Take advantage of external SRAM on more controllers.
 - Numerous bug fixes and performance improvements.
1998-09-15 07:24:17 +00:00