Date: Sun, 4 Jun 2000 14:52:00 +0200 (CEST) From: =?ISO-8859-1?Q?G=E9rard_Roudier?= <groudier@club-internet.fr> To: hackers@FreeBSD.org Subject: PATCH: `sym' driver changes for testing. Message-ID: <Pine.LNX.4.10.10006041448020.307-100000@linux.local>
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I have made available the following `sym' driver patch for testing: http://people.freebsd.org/~groudier/sym-1.6.0-20000604.diffs This patch is against driver version in -current. Changes are pretty trivial and mostly nil-potent for ia32, but it seemed to me they may need some testings, especially on Alpha, (and comments if any are welcome) prior to committing them: 1) Use `bus space' for IO/MMIO instead of legacy IO/MMIO methods. 2) Add preliminary support for big endian. For now, a couple of byte order primitives are defined in the driver code. 3) Add 2 macros OUTL_DSP and OUTONB_STD that perform a memory barrier prior to the IO, since we want the chip to have a consistent view of driver internal data structure each time we restart it. This ensure proper ordering and makes driver code simpler. 4) Add barrier definitions we should need for ia64 and powerpc. These definitions will go away when the kernel will provide them. These additions and changes are intended to help kernel ports once their boot stage will be reached ;-). They also clarify ordering concerns in the driver. The barriers used by the driver are slightly paranoid and in most places only write (store) barriers should be enough. This will be refined when real testing with systems implementing kind of weak ordering will be possible. Status: - All places where the driver has to restart the SCRIPTS processor by writing the DSP or setting the STD bit in dcntl are not time critical and so paranoid barriers will not affect performances. - The driver performs explicit ordering from the C code in 2 places: * To queue the job -> 2 barriers that could be `write memory barriers'. * To ensure INTFLY clear has been seen by chip prior to scanning the done queue, a dummy read is peformed under interrupt. Not perfect but just cool. :) Gérard. PS: This posting went to -hackers and not -scsi since the patch does not address scsi concerns. :-) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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