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diff --git a/Documentation/scsi/hpsa.rst b/Documentation/scsi/hpsa.rst new file mode 100644 index 000000000..340e10c6e --- /dev/null +++ b/Documentation/scsi/hpsa.rst @@ -0,0 +1,129 @@ +.. SPDX-License-Identifier: GPL-2.0 + +========================================= +HPSA - Hewlett Packard Smart Array driver +========================================= + +This file describes the hpsa SCSI driver for HP Smart Array controllers. +The hpsa driver is intended to supplant the cciss driver for newer +Smart Array controllers. The hpsa driver is a SCSI driver, while the +cciss driver is a "block" driver. Actually cciss is both a block +driver (for logical drives) AND a SCSI driver (for tape drives). This +"split-brained" design of the cciss driver is a source of excess +complexity and eliminating that complexity is one of the reasons +for hpsa to exist. + +Supported devices +================= + +- Smart Array P212 +- Smart Array P410 +- Smart Array P410i +- Smart Array P411 +- Smart Array P812 +- Smart Array P712m +- Smart Array P711m +- StorageWorks P1210m + +Additionally, older Smart Arrays may work with the hpsa driver if the kernel +boot parameter "hpsa_allow_any=1" is specified, however these are not tested +nor supported by HP with this driver. For older Smart Arrays, the cciss +driver should still be used. + +The "hpsa_simple_mode=1" boot parameter may be used to prevent the driver from +putting the controller into "performant" mode. The difference is that with simple +mode, each command completion requires an interrupt, while with "performant mode" +(the default, and ordinarily better performing) it is possible to have multiple +command completions indicated by a single interrupt. + +HPSA specific entries in /sys +============================= + + In addition to the generic SCSI attributes available in /sys, hpsa supports + the following attributes: + +HPSA specific host attributes +============================= + + :: + + /sys/class/scsi_host/host*/rescan + /sys/class/scsi_host/host*/firmware_revision + /sys/class/scsi_host/host*/resettable + /sys/class/scsi_host/host*/transport_mode + + the host "rescan" attribute is a write only attribute. Writing to this + attribute will cause the driver to scan for new, changed, or removed devices + (e.g. hot-plugged tape drives, or newly configured or deleted logical drives, + etc.) and notify the SCSI midlayer of any changes detected. Normally this is + triggered automatically by HP's Array Configuration Utility (either the GUI or + command line variety) so for logical drive changes, the user should not + normally have to use this. It may be useful when hot plugging devices like + tape drives, or entire storage boxes containing pre-configured logical drives. + + The "firmware_revision" attribute contains the firmware version of the Smart Array. + For example:: + + root@host:/sys/class/scsi_host/host4# cat firmware_revision + 7.14 + + The transport_mode indicates whether the controller is in "performant" + or "simple" mode. This is controlled by the "hpsa_simple_mode" module + parameter. + + The "resettable" read-only attribute indicates whether a particular + controller is able to honor the "reset_devices" kernel parameter. If the + device is resettable, this file will contain a "1", otherwise, a "0". This + parameter is used by kdump, for example, to reset the controller at driver + load time to eliminate any outstanding commands on the controller and get the + controller into a known state so that the kdump initiated i/o will work right + and not be disrupted in any way by stale commands or other stale state + remaining on the controller from the previous kernel. This attribute enables + kexec tools to warn the user if they attempt to designate a device which is + unable to honor the reset_devices kernel parameter as a dump device. + +HPSA specific disk attributes +----------------------------- + + :: + + /sys/class/scsi_disk/c:b:t:l/device/unique_id + /sys/class/scsi_disk/c:b:t:l/device/raid_level + /sys/class/scsi_disk/c:b:t:l/device/lunid + + (where c:b:t:l are the controller, bus, target and lun of the device) + + For example:: + + root@host:/sys/class/scsi_disk/4:0:0:0/device# cat unique_id + 600508B1001044395355323037570F77 + root@host:/sys/class/scsi_disk/4:0:0:0/device# cat lunid + 0x0000004000000000 + root@host:/sys/class/scsi_disk/4:0:0:0/device# cat raid_level + RAID 0 + +HPSA specific ioctls +==================== + + For compatibility with applications written for the cciss driver, many, but + not all of the ioctls supported by the cciss driver are also supported by the + hpsa driver. The data structures used by these are described in + include/linux/cciss_ioctl.h + + CCISS_DEREGDISK, CCISS_REGNEWDISK, CCISS_REGNEWD + The above three ioctls all do exactly the same thing, which is to cause the driver + to rescan for new devices. This does exactly the same thing as writing to the + hpsa specific host "rescan" attribute. + + CCISS_GETPCIINFO + Returns PCI domain, bus, device and function and "board ID" (PCI subsystem ID). + + CCISS_GETDRIVVER + Returns driver version in three bytes encoded as:: + + (major_version << 16) | (minor_version << 8) | (subminor_version) + + CCISS_PASSTHRU, CCISS_BIG_PASSTHRU + Allows "BMIC" and "CISS" commands to be passed through to the Smart Array. + These are used extensively by the HP Array Configuration Utility, SNMP storage + agents, etc. See cciss_vol_status at http://cciss.sf.net for some examples. |