1392de9d7a
Link: https://lore.kernel.org/r/ea58e04176d43fb7194615b145060aa04c9cf3ad.1583136624.git.mchehab+huawei@kernel.org Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
130 lines
5.1 KiB
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130 lines
5.1 KiB
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.. SPDX-License-Identifier: GPL-2.0
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=========================================
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HPSA - Hewlett Packard Smart Array driver
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=========================================
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This file describes the hpsa SCSI driver for HP Smart Array controllers.
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The hpsa driver is intended to supplant the cciss driver for newer
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Smart Array controllers. The hpsa driver is a SCSI driver, while the
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cciss driver is a "block" driver. Actually cciss is both a block
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driver (for logical drives) AND a SCSI driver (for tape drives). This
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"split-brained" design of the cciss driver is a source of excess
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complexity and eliminating that complexity is one of the reasons
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for hpsa to exist.
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Supported devices
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=================
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- Smart Array P212
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- Smart Array P410
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- Smart Array P410i
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- Smart Array P411
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- Smart Array P812
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- Smart Array P712m
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- Smart Array P711m
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- StorageWorks P1210m
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Additionally, older Smart Arrays may work with the hpsa driver if the kernel
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boot parameter "hpsa_allow_any=1" is specified, however these are not tested
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nor supported by HP with this driver. For older Smart Arrays, the cciss
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driver should still be used.
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The "hpsa_simple_mode=1" boot parameter may be used to prevent the driver from
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putting the controller into "performant" mode. The difference is that with simple
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mode, each command completion requires an interrupt, while with "performant mode"
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(the default, and ordinarily better performing) it is possible to have multiple
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command completions indicated by a single interrupt.
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HPSA specific entries in /sys
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=============================
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In addition to the generic SCSI attributes available in /sys, hpsa supports
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the following attributes:
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HPSA specific host attributes
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=============================
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::
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/sys/class/scsi_host/host*/rescan
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/sys/class/scsi_host/host*/firmware_revision
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/sys/class/scsi_host/host*/resettable
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/sys/class/scsi_host/host*/transport_mode
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the host "rescan" attribute is a write only attribute. Writing to this
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attribute will cause the driver to scan for new, changed, or removed devices
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(e.g. hot-plugged tape drives, or newly configured or deleted logical drives,
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etc.) and notify the SCSI midlayer of any changes detected. Normally this is
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triggered automatically by HP's Array Configuration Utility (either the GUI or
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command line variety) so for logical drive changes, the user should not
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normally have to use this. It may be useful when hot plugging devices like
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tape drives, or entire storage boxes containing pre-configured logical drives.
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The "firmware_revision" attribute contains the firmware version of the Smart Array.
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For example::
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root@host:/sys/class/scsi_host/host4# cat firmware_revision
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7.14
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The transport_mode indicates whether the controller is in "performant"
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or "simple" mode. This is controlled by the "hpsa_simple_mode" module
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parameter.
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The "resettable" read-only attribute indicates whether a particular
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controller is able to honor the "reset_devices" kernel parameter. If the
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device is resettable, this file will contain a "1", otherwise, a "0". This
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parameter is used by kdump, for example, to reset the controller at driver
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load time to eliminate any outstanding commands on the controller and get the
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controller into a known state so that the kdump initiated i/o will work right
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and not be disrupted in any way by stale commands or other stale state
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remaining on the controller from the previous kernel. This attribute enables
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kexec tools to warn the user if they attempt to designate a device which is
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unable to honor the reset_devices kernel parameter as a dump device.
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HPSA specific disk attributes
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-----------------------------
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::
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/sys/class/scsi_disk/c:b:t:l/device/unique_id
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/sys/class/scsi_disk/c:b:t:l/device/raid_level
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/sys/class/scsi_disk/c:b:t:l/device/lunid
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(where c:b:t:l are the controller, bus, target and lun of the device)
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For example::
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root@host:/sys/class/scsi_disk/4:0:0:0/device# cat unique_id
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600508B1001044395355323037570F77
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root@host:/sys/class/scsi_disk/4:0:0:0/device# cat lunid
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0x0000004000000000
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root@host:/sys/class/scsi_disk/4:0:0:0/device# cat raid_level
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RAID 0
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HPSA specific ioctls
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====================
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For compatibility with applications written for the cciss driver, many, but
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not all of the ioctls supported by the cciss driver are also supported by the
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hpsa driver. The data structures used by these are described in
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include/linux/cciss_ioctl.h
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CCISS_DEREGDISK, CCISS_REGNEWDISK, CCISS_REGNEWD
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The above three ioctls all do exactly the same thing, which is to cause the driver
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to rescan for new devices. This does exactly the same thing as writing to the
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hpsa specific host "rescan" attribute.
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CCISS_GETPCIINFO
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Returns PCI domain, bus, device and function and "board ID" (PCI subsystem ID).
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CCISS_GETDRIVVER
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Returns driver version in three bytes encoded as::
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(major_version << 16) | (minor_version << 8) | (subminor_version)
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CCISS_PASSTHRU, CCISS_BIG_PASSTHRU
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Allows "BMIC" and "CISS" commands to be passed through to the Smart Array.
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These are used extensively by the HP Array Configuration Utility, SNMP storage
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agents, etc. See cciss_vol_status at http://cciss.sf.net for some examples.
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