LXR linux/Documentation/scsi/hpsa.rst

   1.. SPDX-License-Identifier: GPL-2.0
   2
   3=========================================
   4HPSA - Hewlett Packard Smart Array driver
   5=========================================
   6
   7This file describes the hpsa SCSI driver for HP Smart Array controllers.
   8The hpsa driver is intended to supplant the cciss driver for newer
   9Smart Array controllers.  The hpsa driver is a SCSI driver, while the
  10cciss driver is a "block" driver.  Actually cciss is both a block
  11driver (for logical drives) AND a SCSI driver (for tape drives). This
  12"split-brained" design of the cciss driver is a source of excess
  13complexity and eliminating that complexity is one of the reasons
  14for hpsa to exist.
  15
  16Supported devices
  17=================
  18
  19- Smart Array P212
  20- Smart Array P410
  21- Smart Array P410i
  22- Smart Array P411
  23- Smart Array P812
  24- Smart Array P712m
  25- Smart Array P711m
  26- StorageWorks P1210m
  27
  28Additionally, older Smart Arrays may work with the hpsa driver if the kernel
  29boot parameter "hpsa_allow_any=1" is specified, however these are not tested
  30nor supported by HP with this driver.  For older Smart Arrays, the cciss
  31driver should still be used.
  32
  33The "hpsa_simple_mode=1" boot parameter may be used to prevent the driver from
  34putting the controller into "performant" mode.  The difference is that with simple
  35mode, each command completion requires an interrupt, while with "performant mode"
  36(the default, and ordinarily better performing) it is possible to have multiple
  37command completions indicated by a single interrupt.
  38
  39HPSA specific entries in /sys
  40=============================
  41
  42  In addition to the generic SCSI attributes available in /sys, hpsa supports
  43  the following attributes:
  44
  45HPSA specific host attributes
  46=============================
  47
  48  ::
  49
  50    /sys/class/scsi_host/host*/rescan
  51    /sys/class/scsi_host/host*/firmware_revision
  52    /sys/class/scsi_host/host*/resettable
  53    /sys/class/scsi_host/host*/transport_mode
  54
  55  the host "rescan" attribute is a write only attribute.  Writing to this
  56  attribute will cause the driver to scan for new, changed, or removed devices
  57  (e.g. hot-plugged tape drives, or newly configured or deleted logical drives,
  58  etc.) and notify the SCSI midlayer of any changes detected.  Normally this is
  59  triggered automatically by HP's Array Configuration Utility (either the GUI or
  60  command line variety) so for logical drive changes, the user should not
  61  normally have to use this.  It may be useful when hot plugging devices like
  62  tape drives, or entire storage boxes containing pre-configured logical drives.
  63
  64  The "firmware_revision" attribute contains the firmware version of the Smart Array.
  65  For example::
  66
  67        root@host:/sys/class/scsi_host/host4# cat firmware_revision
  68        7.14
  69
  70  The transport_mode indicates whether the controller is in "performant"
  71  or "simple" mode.  This is controlled by the "hpsa_simple_mode" module
  72  parameter.
  73
  74  The "resettable" read-only attribute indicates whether a particular
  75  controller is able to honor the "reset_devices" kernel parameter.  If the
  76  device is resettable, this file will contain a "1", otherwise, a "0".  This
  77  parameter is used by kdump, for example, to reset the controller at driver
  78  load time to eliminate any outstanding commands on the controller and get the
  79  controller into a known state so that the kdump initiated i/o will work right
  80  and not be disrupted in any way by stale commands or other stale state
  81  remaining on the controller from the previous kernel.  This attribute enables
  82  kexec tools to warn the user if they attempt to designate a device which is
  83  unable to honor the reset_devices kernel parameter as a dump device.
  84
  85HPSA specific disk attributes
  86-----------------------------
  87
  88  ::
  89
  90    /sys/class/scsi_disk/c:b:t:l/device/unique_id
  91    /sys/class/scsi_disk/c:b:t:l/device/raid_level
  92    /sys/class/scsi_disk/c:b:t:l/device/lunid
  93
  94  (where c:b:t:l are the controller, bus, target and lun of the device)
  95
  96  For example::
  97
  98        root@host:/sys/class/scsi_disk/4:0:0:0/device# cat unique_id
  99        600508B1001044395355323037570F77
 100        root@host:/sys/class/scsi_disk/4:0:0:0/device# cat lunid
 101        0x0000004000000000
 102        root@host:/sys/class/scsi_disk/4:0:0:0/device# cat raid_level
 103        RAID 0
 104
 105HPSA specific ioctls
 106====================
 107
 108  For compatibility with applications written for the cciss driver, many, but
 109  not all of the ioctls supported by the cciss driver are also supported by the
 110  hpsa driver.  The data structures used by these are described in
 111  include/linux/cciss_ioctl.h
 112
 113  CCISS_DEREGDISK, CCISS_REGNEWDISK, CCISS_REGNEWD
 114        The above three ioctls all do exactly the same thing, which is to cause the driver
 115        to rescan for new devices.  This does exactly the same thing as writing to the
 116        hpsa specific host "rescan" attribute.
 117
 118  CCISS_GETPCIINFO
 119        Returns PCI domain, bus, device and function and "board ID" (PCI subsystem ID).
 120
 121  CCISS_GETDRIVVER
 122        Returns driver version in three bytes encoded as::
 123
 124                (major_version << 16) | (minor_version << 8) | (subminor_version)
 125
 126  CCISS_PASSTHRU, CCISS_BIG_PASSTHRU
 127        Allows "BMIC" and "CISS" commands to be passed through to the Smart Array.
 128        These are used extensively by the HP Array Configuration Utility, SNMP storage
 129        agents, etc.  See cciss_vol_status at http://cciss.sf.net for some examples.
 130