0001 .. SPDX-License-Identifier: GPL-2.0
0002
0003 =========================================
0004 HPSA - Hewlett Packard Smart Array driver
0005 =========================================
0006
0007 This file describes the hpsa SCSI driver for HP Smart Array controllers.
0008 The hpsa driver is intended to supplant the cciss driver for newer
0009 Smart Array controllers. The hpsa driver is a SCSI driver, while the
0010 cciss driver is a "block" driver. Actually cciss is both a block
0011 driver (for logical drives) AND a SCSI driver (for tape drives). This
0012 "split-brained" design of the cciss driver is a source of excess
0013 complexity and eliminating that complexity is one of the reasons
0014 for hpsa to exist.
0015
0016 Supported devices
0017 =================
0018
0019 - Smart Array P212
0020 - Smart Array P410
0021 - Smart Array P410i
0022 - Smart Array P411
0023 - Smart Array P812
0024 - Smart Array P712m
0025 - Smart Array P711m
0026 - StorageWorks P1210m
0027
0028 Additionally, older Smart Arrays may work with the hpsa driver if the kernel
0029 boot parameter "hpsa_allow_any=1" is specified, however these are not tested
0030 nor supported by HP with this driver. For older Smart Arrays, the cciss
0031 driver should still be used.
0032
0033 The "hpsa_simple_mode=1" boot parameter may be used to prevent the driver from
0034 putting the controller into "performant" mode. The difference is that with simple
0035 mode, each command completion requires an interrupt, while with "performant mode"
0036 (the default, and ordinarily better performing) it is possible to have multiple
0037 command completions indicated by a single interrupt.
0038
0039 HPSA specific entries in /sys
0040 =============================
0041
0042 In addition to the generic SCSI attributes available in /sys, hpsa supports
0043 the following attributes:
0044
0045 HPSA specific host attributes
0046 =============================
0047
0048 ::
0049
0050 /sys/class/scsi_host/host*/rescan
0051 /sys/class/scsi_host/host*/firmware_revision
0052 /sys/class/scsi_host/host*/resettable
0053 /sys/class/scsi_host/host*/transport_mode
0054
0055 the host "rescan" attribute is a write only attribute. Writing to this
0056 attribute will cause the driver to scan for new, changed, or removed devices
0057 (e.g. hot-plugged tape drives, or newly configured or deleted logical drives,
0058 etc.) and notify the SCSI midlayer of any changes detected. Normally this is
0059 triggered automatically by HP's Array Configuration Utility (either the GUI or
0060 command line variety) so for logical drive changes, the user should not
0061 normally have to use this. It may be useful when hot plugging devices like
0062 tape drives, or entire storage boxes containing pre-configured logical drives.
0063
0064 The "firmware_revision" attribute contains the firmware version of the Smart Array.
0065 For example::
0066
0067 root@host:/sys/class/scsi_host/host4# cat firmware_revision
0068 7.14
0069
0070 The transport_mode indicates whether the controller is in "performant"
0071 or "simple" mode. This is controlled by the "hpsa_simple_mode" module
0072 parameter.
0073
0074 The "resettable" read-only attribute indicates whether a particular
0075 controller is able to honor the "reset_devices" kernel parameter. If the
0076 device is resettable, this file will contain a "1", otherwise, a "0". This
0077 parameter is used by kdump, for example, to reset the controller at driver
0078 load time to eliminate any outstanding commands on the controller and get the
0079 controller into a known state so that the kdump initiated i/o will work right
0080 and not be disrupted in any way by stale commands or other stale state
0081 remaining on the controller from the previous kernel. This attribute enables
0082 kexec tools to warn the user if they attempt to designate a device which is
0083 unable to honor the reset_devices kernel parameter as a dump device.
0084
0085 HPSA specific disk attributes
0086 -----------------------------
0087
0088 ::
0089
0090 /sys/class/scsi_disk/c:b:t:l/device/unique_id
0091 /sys/class/scsi_disk/c:b:t:l/device/raid_level
0092 /sys/class/scsi_disk/c:b:t:l/device/lunid
0093
0094 (where c:b:t:l are the controller, bus, target and lun of the device)
0095
0096 For example::
0097
0098 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat unique_id
0099 600508B1001044395355323037570F77
0100 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat lunid
0101 0x0000004000000000
0102 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat raid_level
0103 RAID 0
0104
0105 HPSA specific ioctls
0106 ====================
0107
0108 For compatibility with applications written for the cciss driver, many, but
0109 not all of the ioctls supported by the cciss driver are also supported by the
0110 hpsa driver. The data structures used by these are described in
0111 include/linux/cciss_ioctl.h
0112
0113 CCISS_DEREGDISK, CCISS_REGNEWDISK, CCISS_REGNEWD
0114 The above three ioctls all do exactly the same thing, which is to cause the driver
0115 to rescan for new devices. This does exactly the same thing as writing to the
0116 hpsa specific host "rescan" attribute.
0117
0118 CCISS_GETPCIINFO
0119 Returns PCI domain, bus, device and function and "board ID" (PCI subsystem ID).
0120
0121 CCISS_GETDRIVVER
0122 Returns driver version in three bytes encoded as::
0123
0124 (major_version << 16) | (minor_version << 8) | (subminor_version)
0125
0126 CCISS_PASSTHRU, CCISS_BIG_PASSTHRU
0127 Allows "BMIC" and "CISS" commands to be passed through to the Smart Array.
0128 These are used extensively by the HP Array Configuration Utility, SNMP storage
0129 agents, etc. See cciss_vol_status at http://cciss.sf.net for some examples.
