sym53c500_cs
sym53c8xx_2
tcm_qla2xxx
+ ufs
scsi_transport_srp/figures
--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+
+=======================
+Universal Flash Storage
+=======================
+
+
+.. Contents
+
+ 1. Overview
+ 2. UFS Architecture Overview
+ 2.1 Application 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
+ 3.3 UFS error handling
+ 3.4 SCSI Error handling
+
+
+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
+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
+physical layer and MIPI Unipro as the link layer.
+
+The main goals of UFS is to provide:
+
+ * Optimized performance:
+
+ For UFS version 1.0 and 1.1 the target performance is as follows:
+
+ - Support for Gear1 is mandatory (rate A: 1248Mbps, rate B: 1457.6Mbps)
+ - Support for Gear2 is optional (rate A: 2496Mbps, rate B: 2915.2Mbps)
+
+ Future version of the standard,
+
+ - Gear3 (rate A: 4992Mbps, rate B: 5830.4Mbps)
+
+ * Low power consumption
+ * High random IOPs and low latency
+
+
+2. UFS Architecture Overview
+============================
+
+UFS has a layered communication architecture which is based on SCSI
+SAM-5 architectural model.
+
+UFS communication architecture consists of following layers,
+
+2.1 Application Layer
+---------------------
+
+ The Application layer is composed of 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.
+
+ UFS supports subset of SCSI commands defined by SPC-4 and SBC-3.
+
+ * UCS:
+ It handles SCSI commands supported by UFS specification.
+ * Task manager:
+ It handles task management functions defined by the
+ UFS which are meant for command queue control.
+ * Device manager:
+ It handles device level operations and device
+ configuration operations. Device level operations mainly involve
+ device power management operations and commands to Interconnect
+ layers. Device level configurations involve handling of query
+ requests which are used to modify and retrieve configuration
+ information of the device.
+
+2.2 UFS Transport Protocol(UTP) layer
+-------------------------------------
+
+ UTP layer provides services for
+ the higher layers through Service Access Points. UTP defines 3
+ service access points for higher layers.
+
+ * UDM_SAP: Device manager service access point is exposed to device
+ 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.
+ * 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).
+
+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
+ MIPI UniPro and MIPI M-PHY. UIC provides 2 service access points
+ to upper layer,
+
+ * UIC_SAP: To transport UPIU between UFS host and UFS device.
+ * UIO_SAP: To issue commands to Unipro 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 current UFSHCD implementation supports 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
+ 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
+ host controller in the form of UPIUs and intimates the SCSI Midlayer
+ of the status of the command.
+
+3.3 UFS error handling
+----------------------
+
+ Error handling module handles Host controller fatal 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.
+ 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
+functionality are not implemented.
+
+4. BSG Support
+==============
+
+This transport driver supports exchanging UFS protocol information units
+(UPIUs) with a UFS device. Typically, user space will allocate
+struct ufs_bsg_request and struct ufs_bsg_reply (see ufs_bsg.h) as
+request_upiu and reply_upiu respectively. Filling those UPIUs should
+be done in accordance with JEDEC spec UFS2.1 paragraph 10.7.
+*Caveat emptor*: The driver makes no further input validations and sends the
+UPIU to the device as it is. Open the bsg device in /dev/ufs-bsg and
+send SG_IO with the applicable sg_io_v4::
+
+ io_hdr_v4.guard = 'Q';
+ io_hdr_v4.protocol = BSG_PROTOCOL_SCSI;
+ io_hdr_v4.subprotocol = BSG_SUB_PROTOCOL_SCSI_TRANSPORT;
+ io_hdr_v4.response = (__u64)reply_upiu;
+ io_hdr_v4.max_response_len = reply_len;
+ io_hdr_v4.request_len = request_len;
+ io_hdr_v4.request = (__u64)request_upiu;
+ if (dir == SG_DXFER_TO_DEV) {
+ io_hdr_v4.dout_xfer_len = (uint32_t)byte_cnt;
+ io_hdr_v4.dout_xferp = (uintptr_t)(__u64)buff;
+ } else {
+ io_hdr_v4.din_xfer_len = (uint32_t)byte_cnt;
+ io_hdr_v4.din_xferp = (uintptr_t)(__u64)buff;
+ }
+
+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:
+
+ 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 - http://www.jedec.org/sites/default/files/docs/JESD220.pdf
+- UFSHCI - http://www.jedec.org/sites/default/files/docs/JESD223.pdf
+++ /dev/null
- Universal Flash Storage
- =======================
-
-
-Contents
---------
-
-1. Overview
-2. UFS Architecture Overview
- 2.1 Application 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
- 3.3 UFS error handling
- 3.4 SCSI Error handling
-
-
-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
-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
-physical layer and MIPI Unipro as the link layer.
-
-The main goals of UFS is to provide,
- * Optimized performance:
- For UFS version 1.0 and 1.1 the target performance is as follows,
- Support for Gear1 is mandatory (rate A: 1248Mbps, rate B: 1457.6Mbps)
- Support for Gear2 is optional (rate A: 2496Mbps, rate B: 2915.2Mbps)
- Future version of the standard,
- Gear3 (rate A: 4992Mbps, rate B: 5830.4Mbps)
- * Low power consumption
- * High random IOPs and low latency
-
-
-2. UFS Architecture Overview
-----------------------------
-
-UFS has a layered communication architecture which is based on SCSI
-SAM-5 architectural model.
-
-UFS communication architecture consists of following layers,
-
-2.1 Application Layer
-
- The Application layer is composed of 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.
- UFS supports subset of SCSI commands defined by SPC-4 and SBC-3.
- * UCS: It handles SCSI commands supported by UFS specification.
- * Task manager: It handles task management functions defined by the
- UFS which are meant for command queue control.
- * Device manager: It handles device level operations and device
- configuration operations. Device level operations mainly involve
- device power management operations and commands to Interconnect
- layers. Device level configurations involve handling of query
- requests which are used to modify and retrieve configuration
- information of the device.
-
-2.2 UFS Transport Protocol(UTP) layer
-
- UTP layer provides services for
- the higher layers through Service Access Points. UTP defines 3
- service access points for higher layers.
- * UDM_SAP: Device manager service access point is exposed to device
- 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.
- * 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).
-
-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
- MIPI UniPro and MIPI M-PHY. UIC provides 2 service access points
- to upper layer,
- * UIC_SAP: To transport UPIU between UFS host and UFS device.
- * UIO_SAP: To issue commands to Unipro 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 current UFSHCD implementation supports 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
- 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
- host controller in the form of UPIUs and intimates the SCSI Midlayer
- of the status of the command.
-
-3.3 UFS error handling
-
- Error handling module handles Host controller fatal 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.
- 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
-functionality are not implemented.
-
-4. BSG Support
-------------------
-
-This transport driver supports exchanging UFS protocol information units
-(UPIUs) with a UFS device. Typically, user space will allocate
-struct ufs_bsg_request and struct ufs_bsg_reply (see ufs_bsg.h) as
-request_upiu and reply_upiu respectively. Filling those UPIUs should
-be done in accordance with JEDEC spec UFS2.1 paragraph 10.7.
-*Caveat emptor*: The driver makes no further input validations and sends the
-UPIU to the device as it is. Open the bsg device in /dev/ufs-bsg and
-send SG_IO with the applicable sg_io_v4:
-
- io_hdr_v4.guard = 'Q';
- io_hdr_v4.protocol = BSG_PROTOCOL_SCSI;
- io_hdr_v4.subprotocol = BSG_SUB_PROTOCOL_SCSI_TRANSPORT;
- io_hdr_v4.response = (__u64)reply_upiu;
- io_hdr_v4.max_response_len = reply_len;
- io_hdr_v4.request_len = request_len;
- io_hdr_v4.request = (__u64)request_upiu;
- if (dir == SG_DXFER_TO_DEV) {
- io_hdr_v4.dout_xfer_len = (uint32_t)byte_cnt;
- io_hdr_v4.dout_xferp = (uintptr_t)(__u64)buff;
- } else {
- io_hdr_v4.din_xfer_len = (uint32_t)byte_cnt;
- io_hdr_v4.din_xferp = (uintptr_t)(__u64)buff;
- }
-
-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:
-
- 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 - http://www.jedec.org/sites/default/files/docs/JESD220.pdf
-UFSHCI - http://www.jedec.org/sites/default/files/docs/JESD223.pdf
R: Avri Altman <avri.altman@wdc.com>
L: linux-scsi@vger.kernel.org
S: Supported
-F: Documentation/scsi/ufs.txt
+F: Documentation/scsi/ufs.rst
F: drivers/scsi/ufs/
UNIVERSAL FLASH STORAGE HOST CONTROLLER DRIVER DWC HOOKS
The module will be called ufshcd.
To compile this driver as a module, choose M here and read
- <file:Documentation/scsi/ufs.txt>.
+ <file:Documentation/scsi/ufs.rst>.
However, do not compile this as a module if your root file system
(the one containing the directory /) is located on a UFS device.
projects / platform / kernel / linux-rpi.git / commitdiff