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