scsi: docs: convert ufs.txt to ReST
Link: https://lore.kernel.org/r/052d45576e342a217185e91a83793b384b1592a4.1583136624.git.mchehab+huawei@kernel.org Acked-by: Avri Altman <avri.altman@wdc.com> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Mauro Carvalho Chehab
Martin K. Petersen
parent
e92c45d272
commit
b64f682240
|
|
@ -44,5 +44,6 @@ Linux SCSI Subsystem
|
|||
sym53c500_cs
|
||||
sym53c8xx_2
|
||||
tcm_qla2xxx
|
||||
ufs
|
||||
|
||||
scsi_transport_srp/figures
|
||||
|
|
|
|||
|
|
@ -1,24 +1,26 @@
|
|||
Universal Flash Storage
|
||||
=======================
|
||||
.. SPDX-License-Identifier: GPL-2.0
|
||||
|
||||
=======================
|
||||
Universal Flash Storage
|
||||
=======================
|
||||
|
||||
|
||||
Contents
|
||||
--------
|
||||
.. 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
|
||||
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
|
||||
|
|
@ -28,19 +30,25 @@ 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,
|
||||
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)
|
||||
|
||||
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)
|
||||
|
||||
- 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.
|
||||
|
|
@ -48,16 +56,22 @@ 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
|
||||
|
||||
* 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
|
||||
* 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
|
||||
|
|
@ -65,10 +79,12 @@ UFS communication architecture consists of following layers,
|
|||
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.
|
||||
|
|
@ -76,20 +92,23 @@ UFS communication architecture consists of following layers,
|
|||
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
|
||||
|
|
@ -98,12 +117,14 @@ 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
|
||||
|
|
@ -112,11 +133,13 @@ The current UFSHCD implementation supports following functionality,
|
|||
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
|
||||
|
|
@ -129,7 +152,7 @@ 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
|
||||
|
|
@ -138,7 +161,7 @@ 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:
|
||||
send SG_IO with the applicable sg_io_v4::
|
||||
|
||||
io_hdr_v4.guard = 'Q';
|
||||
io_hdr_v4.protocol = BSG_PROTOCOL_SCSI;
|
||||
|
|
@ -166,6 +189,7 @@ upiu-based protocol is available at:
|
|||
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
|
||||
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
|
||||
|
|
@ -17140,7 +17140,7 @@ R: Alim Akhtar <alim.akhtar@samsung.com>
|
|||
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
|
||||
|
|
|
|||
|
|
@ -46,7 +46,7 @@ config SCSI_UFSHCD
|
|||
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.
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue