Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  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 
 43 Note, cmd_per_lun could give us some trouble, so I'm setting it very low.
 44 Likewise, SCSI_CCISS_CAN_QUEUE is set very conservatively.
 45 
 46 If the upper scsi layer tries to track how many commands we have 
 47 outstanding, it will be operating under the misapprehension that it is
 48 the only one sending us requests.  We also have the block interface,
 49 which is where most requests must surely come from, so the upper layer's
 50 notion of how many requests we have outstanding will be wrong most or
 51 all of the time. 
 52 
 53 Note, the normal SCSI mid-layer error handling doesn't work well
 54 for this driver because 1) it takes the io_request_lock before
 55 calling error handlers and uses a local variable to store flags,
 56 so the io_request_lock cannot be released and interrupts enabled
 57 inside the error handlers, and, the error handlers cannot poll
 58 for command completion because they might get commands from the
 59 block half of the driver completing, and not know what to do
 60 with them.  That's what we get for making a hybrid scsi/block
 61 driver, I suppose.
 62 
 63 */
 64 
 65 struct 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 
 75 struct 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 
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