[4657] in linux-scsi channel archive
New ncr53c8xx driver experimental version.
daemon@ATHENA.MIT.EDU (Gerard Roudier)
Sat Sep 5 06:54:22 1998
Date: Sat, 5 Sep 1998 11:59:11 +0200 (MET DST)
From: Gerard Roudier <groudier@club-internet.fr>
To: linux-scsi@vger.rutgers.edu, ncr53c810@colorado.edu
Hello,
I have made available a heavily changed ncr53c8xx driver at:
ftp://ftp.tux.org/pub/roudier/896/
(One tar file + 3 patches)
This driver version is primarily intended for support of the new
64 bit PCI 53C896 Symbios controller.
For now, I donnot know if this code actually works for the 896 since
I donnot have any appropriate hardware for testing this.
I donnot like to announce too incomplete code, but this one is very
interesting in my opinion. The new driver uses LOAD/STORE SCRIPTS
instructions. This makes it unable to work with normal 810, 815 and
825 controllers, but it supports all recent SYMBIOS chips, e.g:
810A (rev >= 16)
825A (rec >= 16)
860
875/876
895
896 once it will be tested.
Generic NCR53C8XX controller SCRIPTS use MOVE MEMORY scripts instructions
in order to support the whole 53C8XX family. This instruction is only able
to use absolute addressing mode and is coded with 3 DWORDS.
LOAD/STORE also support absolute mode, support DSA relative addressing
mode and is coded using only 2 DWORDS.
Most of things that were nasty to implement with MOVE MEMORY becomes easy
and clean using LOAD/STORE. No need to implement self-modified SCRIPTS
code for indirect addressing and coding SCRIPTS becomes a lot easier and
clearer.
Win against the stock ncr53c8xx driver is:
- Simpler driver code.
- Faster SCRIPTS code (12 micro-seconds / command actually measured).
- No self-modifying SCRIPTS patterns.
Obviously, this driver is not usable on systems that still have
old-designed 810, 815 or 825 controllers.
BTW, this driver works fine on my system:
- 810A attached to 1 CD TOSH 3401B.
- 875 1 Atlas I W + 2 ATlas II UW + 1 DDRS UW.
- 895 1 Cheatah LVD + 1 Viking II LVD.
It also seems not to have bad effects on Guinea pigs I use for
experimenting new code. :-)
Regards,
Gerard.
PS: Donnot ask me if the stock ncr53c8xx maintainance is dropped.
I will drop support for old NCR53C8XX chips in the ncr53c8xx driver at
the time Linux will drop support for 486 processors. :-)
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