SMARTPQI Microchip Smart Storage SCSI driver

PQI queuing model과 Series 9 전환

`smartpqi`는 Microchip PQI controller용 차세대 SCSI driver이며 PQI queuing model을 처음 구현한 SCSI driver다. Microchip 정보는 `http://www.microchip.com`에서 확인한다.

Adaptec Series 9 controller에서는 `smartpqi`가 `aacraid`를 대체한다. 4.9 이전 kernel에서 Series 9를 사용하는 고객은 `smartpqi`를 설정해야 volume이 OS에 추가된다. Microchip smartpqi controller 지원이 필요하면 kernel 구성에서 이 driver를 활성화한다.

PQI Queuing Interface에 관한 추가 정보는 `http://www.t10.org/drafts.htm`과 `http://www.t10.org/members/w_pqi2.htm`을 참고한다.

.. SPDX-License-Identifier: GPL-2.0

==============================================
SMARTPQI - Microchip Smart Storage SCSI driver
==============================================

This file describes the smartpqi SCSI driver for Microchip
(http://www.microchip.com) PQI controllers. The smartpqi driver
is the next generation SCSI driver for Microchip Corp. The smartpqi
driver is the first SCSI driver to implement the PQI queuing model.

The smartpqi driver will replace the aacraid driver for Adaptec Series 9
controllers. Customers running an older kernel (Pre-4.9) using an Adaptec
Series 9 controller will have to configure the smartpqi driver or their
volumes will not be added to the OS.

For Microchip smartpqi controller support, enable the smartpqi driver
when configuring the kernel.

For more information on the PQI Queuing Interface, please see:

- http://www.t10.org/drafts.htm
- http://www.t10.org/members/w_pqi2.htm

지원 장치 목록 상태

지원 controller 이름은 공개되는 대로 문서에 추가될 예정이다.

Supported devices
=================
<Controller names to be added as they become publicly available.>

Host rescan과 version attribute

Smartpqi host는 `/sys/class/scsi_host/host*/rescan`과 `/sys/class/scsi_host/host*/driver_version` attribute를 제공한다. `rescan`은 write-only이며 값을 쓰면 driver가 새 장치, 변경된 장치, 제거된 장치를 scan하고 발견한 변경을 SCSI mid-layer에 알린다.

Version attribute는 read-only이며 driver version과 controller firmware version을 반환한다. 예시 출력은 `driver: 0.9.13-370`, `firmware: 0.01-522`다.

smartpqi specific entries in /sys
=================================

smartpqi host attributes
------------------------
  - /sys/class/scsi_host/host*/rescan
  - /sys/class/scsi_host/host*/driver_version

  The host rescan attribute is a write only attribute. Writing to this
  attribute will trigger the driver to scan for new, changed, or removed
  devices and notify the SCSI mid-layer of any changes detected.

  The version attribute is read-only and will return the driver version
  and the controller firmware version.
  For example::

              driver: 0.9.13-370
              firmware: 0.01-522

SAS transport가 추가하는 device attribute

HBA 장치는 SAS transport layer에 추가되며 transport layer가 SAS device attribute를 자동으로 만든다. 경로는 `/sys/class/sas_device/end_device-X:X/sas_address`, `enclosure_identifier`, `scsi_target_id`다.

smartpqi sas device attributes
------------------------------
  HBA devices are added to the SAS transport layer. These attributes are
  automatically added by the SAS transport layer.

  /sys/class/sas_device/end_device-X:X/sas_address
  /sys/class/sas_device/end_device-X:X/enclosure_identifier
  /sys/class/sas_device/end_device-X:X/scsi_target_id

cciss 호환 ioctl

Smartpqi 전용 ioctl은 `cciss` protocol용 application과의 호환성을 제공한다. `CCISS_DEREGDISK`, `CCISS_REGNEWDISK`, `CCISS_REGNEWD`는 모두 같은 동작을 한다. Driver에 새 장치를 다시 scan하게 하며 host `rescan` attribute에 쓰는 것과 정확히 같다.

`CCISS_GETPCIINFO`는 PCI domain, bus, device, function과 board ID인 PCI subsystem ID를 반환한다. `CCISS_GETDRIVVER`는 driver version을 세 byte로 반환하며 `(DRIVER_MAJOR << 28) | (DRIVER_MINOR << 24) | (DRIVER_RELEASE << 16) | DRIVER_REVISION`으로 encode한다.

`CCISS_PASSTHRU`는 `BMIC`과 `CISS` 명령을 Smart Storage Array로 전달한다. SSA Array Configuration Utility와 SNMP storage agent 등이 이 기능을 광범위하게 사용한다.

smartpqi specific ioctls
========================

  For compatibility with applications written for the cciss protocol.

  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
        smartpqi 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::

          (DRIVER_MAJOR << 28) | (DRIVER_MINOR << 24) | (DRIVER_RELEASE << 16) | DRIVER_REVISION;

  CCISS_PASSTHRU
        Allows "BMIC" and "CISS" commands to be passed through to the Smart Storage Array.
        These are used extensively by the SSA Array Configuration Utility, SNMP storage
        agents, etc.