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/drivers/block/cciss_scsi.h

https://bitbucket.org/evzijst/gittest
C Header | 79 lines | 19 code | 7 blank | 53 comment | 0 complexity | 69423aeb4fd2bfe9d9b79ddede7cb168 MD5 | raw file
 1/*
 2 *    Disk Array driver for Compaq SA53xx Controllers, SCSI Tape module
 3 *    Copyright 2001 Compaq Computer Corporation
 4 *
 5 *    This program is free software; you can redistribute it and/or modify
 6 *    it under the terms of the GNU General Public License as published by
 7 *    the Free Software Foundation; either version 2 of the License, or
 8 *    (at your option) any later version.
 9 *
10 *    This program is distributed in the hope that it will be useful,
11 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
12 *    MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
13 *    NON INFRINGEMENT.  See the GNU General Public License for more details.
14 *
15 *    You should have received a copy of the GNU General Public License
16 *    along with this program; if not, write to the Free Software
17 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
18 *
19 *    Questions/Comments/Bugfixes to iss_storagedev@hp.com
20 *
21 */
22#ifdef CONFIG_CISS_SCSI_TAPE
23#ifndef _CCISS_SCSI_H_
24#define _CCISS_SCSI_H_
25
26#include <scsi/scsicam.h> /* possibly irrelevant, since we don't show disks */
27
28		// the scsi id of the adapter...
29#define SELF_SCSI_ID 15
30		// 15 is somewhat arbitrary, since the scsi-2 bus
31		// that's presented by the driver to the OS is
32		// fabricated.  The "real" scsi-3 bus the 
33		// hardware presents is fabricated too.
34		// The actual, honest-to-goodness physical
35		// bus that the devices are attached to is not 
36		// addressible natively, and may in fact turn
37		// out to be not scsi at all.
38
39#define SCSI_CCISS_CAN_QUEUE 2
40
41/* 
42
43Note, cmd_per_lun could give us some trouble, so I'm setting it very low.
44Likewise, SCSI_CCISS_CAN_QUEUE is set very conservatively.
45
46If the upper scsi layer tries to track how many commands we have 
47outstanding, it will be operating under the misapprehension that it is
48the only one sending us requests.  We also have the block interface,
49which is where most requests must surely come from, so the upper layer's
50notion of how many requests we have outstanding will be wrong most or
51all of the time. 
52
53Note, the normal SCSI mid-layer error handling doesn't work well
54for this driver because 1) it takes the io_request_lock before
55calling error handlers and uses a local variable to store flags,
56so the io_request_lock cannot be released and interrupts enabled
57inside the error handlers, and, the error handlers cannot poll
58for command completion because they might get commands from the
59block half of the driver completing, and not know what to do
60with them.  That's what we get for making a hybrid scsi/block
61driver, I suppose.
62
63*/
64
65struct cciss_scsi_dev_t {
66	int devtype;
67	int bus, target, lun;		/* as presented to the OS */
68	unsigned char scsi3addr[8];	/* as presented to the HW */
69};
70
71struct cciss_scsi_hba_t {
72	char *name;
73	int ndevices;
74#define CCISS_MAX_SCSI_DEVS_PER_HBA 16
75	struct cciss_scsi_dev_t dev[CCISS_MAX_SCSI_DEVS_PER_HBA];
76};
77
78#endif /* _CCISS_SCSI_H_ */
79#endif /* CONFIG_CISS_SCSI_TAPE */