Date: Sun, 22 Nov 1998 17:33:49 -0800 (PST) From: "Justin T. Gibbs" <gibbs@FreeBSD.ORG> To: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: cvs commit: src/sys/dev/aic7xxx aic7xxx.c aic7xxx.h aic7xxx.reg aic7xxx.seq Message-ID: <199811230133.RAA06417@freefall.freebsd.org>
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gibbs 1998/11/22 17:33:49 PST
Modified files:
sys/dev/aic7xxx aic7xxx.c aic7xxx.h aic7xxx.reg
aic7xxx.seq
Log:
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.
Revision Changes Path
1.10 +29 -31 src/sys/dev/aic7xxx/aic7xxx.c
1.2 +20 -9 src/sys/dev/aic7xxx/aic7xxx.h
1.8 +21 -5 src/sys/dev/aic7xxx/aic7xxx.reg
1.80 +29 -38 src/sys/dev/aic7xxx/aic7xxx.seq
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