LXR linux/drivers/block/cciss

   1/*
   2 *    Disk Array driver for HP Smart Array controllers, SCSI Tape module.
   3 *    (C) Copyright 2001, 2007 Hewlett-Packard Development Company, L.P.
   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; version 2 of the License.
   8 *
   9 *    This program is distributed in the hope that it will be useful,
  10 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 *    MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  12 *    General Public License for more details.
  13 *
  14 *    You should have received a copy of the GNU General Public License
  15 *    along with this program; if not, write to the Free Software
  16 *    Foundation, Inc., 59 Temple Place, Suite 300, Boston, MA
  17 *    02111-1307, 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        unsigned char device_id[16];    /* from inquiry pg. 0x83 */
  70        unsigned char vendor[8];        /* bytes 8-15 of inquiry data */
  71        unsigned char model[16];        /* bytes 16-31 of inquiry data */
  72        unsigned char revision[4];      /* bytes 32-35 of inquiry data */
  73};
  74
  75struct cciss_scsi_hba_t {
  76        char *name;
  77        int ndevices;
  78#define CCISS_MAX_SCSI_DEVS_PER_HBA 16
  79        struct cciss_scsi_dev_t dev[CCISS_MAX_SCSI_DEVS_PER_HBA];
  80};
  81
  82#endif /* _CCISS_SCSI_H_ */
  83#endif /* CONFIG_CISS_SCSI_TAPE */
  84