Commit 296559d4 authored by Randy Dunlap's avatar Randy Dunlap Committed by Martin K. Petersen

scsi: ufs: docs: UFS documentation corrections

Make a variety of corrections to ufs.rst:

 - add spaces around parenthetical phrases
 - correct singular/plural grammar and nouns
 - correct punctuation
 - add article adjectives
 - add hyphens to multi-word adjectives
 - spell Lun as LUN
 - spell upiu as UPIU (in text, not code examples)
 - don't capitalize generic "specification"

Link: https://lore.kernel.org/r/20220307013224.5130-1-rdunlap@infradead.org
Cc: Alim Akhtar <alim.akhtar@samsung.com>
Cc: Avri Altman <avri.altman@wdc.com>
Cc: "James E.J. Bottomley" <jejb@linux.ibm.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: linux-scsi@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 208cc9fe
......@@ -10,8 +10,8 @@ Universal Flash Storage
1. Overview
2. UFS Architecture Overview
2.1 Application Layer
2.2 UFS Transport Protocol(UTP) layer
2.3 UFS Interconnect(UIC) Layer
2.2 UFS Transport Protocol (UTP) layer
2.3 UFS Interconnect (UIC) Layer
3. UFSHCD Overview
3.1 UFS controller initialization
3.2 UTP Transfer requests
......@@ -22,15 +22,15 @@ Universal Flash Storage
1. Overview
===========
Universal Flash Storage(UFS) is a storage specification for flash devices.
It is aimed to provide a universal storage interface for both
embedded and removable flash memory based storage in mobile
Universal Flash Storage (UFS) is a storage specification for flash devices.
It aims to provide a universal storage interface for both
embedded and removable flash memory-based storage in mobile
devices such as smart phones and tablet computers. The specification
is defined by JEDEC Solid State Technology Association. UFS is based
on MIPI M-PHY physical layer standard. UFS uses MIPI M-PHY as the
on the MIPI M-PHY physical layer standard. UFS uses MIPI M-PHY as the
physical layer and MIPI Unipro as the link layer.
The main goals of UFS is to provide:
The main goals of UFS are to provide:
* Optimized performance:
......@@ -53,17 +53,17 @@ The main goals of UFS is to provide:
UFS has a layered communication architecture which is based on SCSI
SAM-5 architectural model.
UFS communication architecture consists of following layers,
UFS communication architecture consists of the following layers.
2.1 Application Layer
---------------------
The Application layer is composed of UFS command set layer(UCS),
The Application layer is composed of the UFS command set layer (UCS),
Task Manager and Device manager. The UFS interface is designed to be
protocol agnostic, however SCSI has been selected as a baseline
protocol for versions 1.0 and 1.1 of UFS protocol layer.
protocol for versions 1.0 and 1.1 of the UFS protocol layer.
UFS supports subset of SCSI commands defined by SPC-4 and SBC-3.
UFS supports a subset of SCSI commands defined by SPC-4 and SBC-3.
* UCS:
It handles SCSI commands supported by UFS specification.
......@@ -78,10 +78,10 @@ UFS communication architecture consists of following layers,
requests which are used to modify and retrieve configuration
information of the device.
2.2 UFS Transport Protocol(UTP) layer
-------------------------------------
2.2 UFS Transport Protocol (UTP) layer
--------------------------------------
UTP layer provides services for
The UTP layer provides services for
the higher layers through Service Access Points. UTP defines 3
service access points for higher layers.
......@@ -89,19 +89,19 @@ UFS communication architecture consists of following layers,
manager for device level operations. These device level operations
are done through query requests.
* UTP_CMD_SAP: Command service access point is exposed to UFS command
set layer(UCS) to transport commands.
set layer (UCS) to transport commands.
* UTP_TM_SAP: Task management service access point is exposed to task
manager to transport task management functions.
UTP transports messages through UFS protocol information unit(UPIU).
UTP transports messages through UFS protocol information unit (UPIU).
2.3 UFS Interconnect(UIC) Layer
-------------------------------
2.3 UFS Interconnect (UIC) Layer
--------------------------------
UIC is the lowest layer of UFS layered architecture. It handles
connection between UFS host and UFS device. UIC consists of
UIC is the lowest layer of the UFS layered architecture. It handles
the connection between UFS host and UFS device. UIC consists of
MIPI UniPro and MIPI M-PHY. UIC provides 2 service access points
to upper layer,
to upper layer:
* UIC_SAP: To transport UPIU between UFS host and UFS device.
* UIO_SAP: To issue commands to Unipro layers.
......@@ -110,25 +110,25 @@ UFS communication architecture consists of following layers,
3. UFSHCD Overview
==================
The UFS host controller driver is based on Linux SCSI Framework.
UFSHCD is a low level device driver which acts as an interface between
SCSI Midlayer and PCIe based UFS host controllers.
The UFS host controller driver is based on the Linux SCSI Framework.
UFSHCD is a low-level device driver which acts as an interface between
the SCSI Midlayer and PCIe-based UFS host controllers.
The current UFSHCD implementation supports following functionality,
The current UFSHCD implementation supports the following functionality:
3.1 UFS controller initialization
---------------------------------
The initialization module brings UFS host controller to active state
and prepares the controller to transfer commands/response between
The initialization module brings the UFS host controller to active state
and prepares the controller to transfer commands/responses between
UFSHCD and UFS device.
3.2 UTP Transfer requests
-------------------------
Transfer request handling module of UFSHCD receives SCSI commands
from SCSI Midlayer, forms UPIUs and issues the UPIUs to UFS Host
controller. Also, the module decodes, responses received from UFS
from the SCSI Midlayer, forms UPIUs and issues the UPIUs to the UFS Host
controller. Also, the module decodes responses received from the UFS
host controller in the form of UPIUs and intimates the SCSI Midlayer
of the status of the command.
......@@ -136,19 +136,19 @@ The current UFSHCD implementation supports following functionality,
----------------------
Error handling module handles Host controller fatal errors,
Device fatal errors and UIC interconnect layer related errors.
Device fatal errors and UIC interconnect layer-related errors.
3.4 SCSI Error handling
-----------------------
This is done through UFSHCD SCSI error handling routines registered
with SCSI Midlayer. Examples of some of the error handling commands
issues by SCSI Midlayer are Abort task, Lun reset and host reset.
with the SCSI Midlayer. Examples of some of the error handling commands
issues by the SCSI Midlayer are Abort task, LUN reset and host reset.
UFSHCD Routines to perform these tasks are registered with
SCSI Midlayer through .eh_abort_handler, .eh_device_reset_handler and
.eh_host_reset_handler.
In this version of UFSHCD Query requests and power management
In this version of UFSHCD, Query requests and power management
functionality are not implemented.
4. BSG Support
......@@ -182,14 +182,14 @@ If you wish to read or write a descriptor, use the appropriate xferp of
sg_io_v4.
The userspace tool that interacts with the ufs-bsg endpoint and uses its
upiu-based protocol is available at:
UPIU-based protocol is available at:
https://github.com/westerndigitalcorporation/ufs-tool
For more detailed information about the tool and its supported
features, please see the tool's README.
UFS Specifications can be found at:
UFS specifications can be found at:
- UFS - http://www.jedec.org/sites/default/files/docs/JESD220.pdf
- UFSHCI - http://www.jedec.org/sites/default/files/docs/JESD223.pdf
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