Provision UFS device - Qualcomm Dragonwing Documentation

Provisioning refers to the process of creating and defining LUNs on a new UFS device. A UFS device has one or more logical units. A logical unit is an independent processing entity within the device. Each logical unit has an address within the UFS device called a Logical Unit Number (LUN). The configuration file for provisioning is at <build root/common/config/ufs/provision. The provision XML files for the various UFS device versions are as follows:

provision_ufs22.xml - This is for UFS device 2.2 part
provision_ufs31.xml - This is for UFS device 3.1 part

In the UFS device provision XML file, the UFS Device Descriptor is a section that has essential information about the UFS device being provisioned. The Device Descriptor includes details such as number of LUNs, initial power modes, write boost parameters. Here is a sample device descriptor entry:

<ufs bNumberLU="6" bBootEnable="1" bDescrAccessEn="0" bInitPowerMode="1" bHighPriorityLUN="0x5" bSecureRemovalType="0"
bInitActiveICCLevel="0" wPeriodicRTCUpdate="0" bConfigDescrLock="0" bWriteBoosterBufferPreserveUserSpaceEn="1" bWriteBoosterBufferType="1"
shared_wb_buffer_size_in_kb="4194304" />

The provision XML file also describes each LUN with Unit Descriptor parameters such as Logical Unit Enable, Boot LUN ID. The following is a sample LUN descriptor entry:

<ufs LUNum="0" bLUEnable="1" bBootLunID="0" size_in_kb="4096" bDataReliability="0" bLUWriteProtect="0" bMemoryType="0"
bLogicalBlockSize="0x0c" bProvisioningType="2" wContextCapabilities="0" wb_buffer_size_in_kb="0"
desc="LU 0 - User LUN - Rest of the device" />

The following table describes some important parameters used in the provision XML files.

Parameter	Description
`bNumberLU`	Number of Logical Units. `bNumberLU` does not include well-known logical units.
`bBootEnable`	Indicates whether the device is enabled for boot: `00h` = Boot feature disabled, `01h` = Bootable feature enabled
`bDescrAccessEn`	Indicates whether the Device Descriptor can be read after the partial initialization phase of the boot sequence: `00h` = Device Descriptor access disabled, `01h` = Device Descriptor access enabled
`BInitPowerMode`	Defines the Power Mode after device initialization or hardware reset: `00h` = UFS-Sleep Mode, `01h` = Active Mode
`bHighPriorityLUN`	Defines the high-priority logical unit
`bSecureRemovalType`	`00h` = Information removed by an erase of the physical memory; `01h` = Information removed by overwriting the addressed locations with a single character followed by an erase; `02h` = Information removed by overwriting the addressed locations with a character, its complement, then a random character; `03h` = Information removed using a vendor-defined mechanism
`bConfigDescrLock`	`0h` = Configuration Descriptor not locked; `1h` = Configuration Descriptor locked

To reprovision the UFS device, set bConfigDescrLock="0". This parameter is part of the provision XML file.
To prevent reprovisioning, set bConfigDescrLock="1" after the UFS device configuration and provisioning is finalized.

Parameter	Description
`LUNum`	Logical Unit Number
`bLUEnable`	Enables/disables the logical unit: `00h` = Disables the logical unit, `01h` = Enables the logical unit
`bBootLunID`	Boot LUN ID: `00h` = Not bootable, `01h` = Boot LU A, `02h` = Boot LU B
`size_in_kb`	Specifies LUN size in KBs
`bLUWriteProtect`	Logical Unit Write Protect: `00h` = LU is not write protected, `01h` = LU write protected when `fPowerOnWPEn = 1`
`bMemoryType`	Defines logical unit memory type: `00h` = Normal memory, `01h` = System code memory type, `02h` = Non-Persistent memory type, `03h` = Enhanced memory type 1, `04h` = Enhanced memory type 2, `05h` = Enhanced memory type 3, `06h` = Enhanced memory type 4
`bProvisioningType`	Provisioning type: `00h` = Thin Provisioning is disabled, `02h` = Enables thin provisioning with `TPRZ = 0`

UFS device partition layout

The default UFS device provisioning creates eight LUNs (LUN0 to LUN7).

The Linux data and all Linux file system images are stored in LUN0.
Boot well-known LUN (WLUN) 0xB0 alternates between LUN1 and LUN2 to provide a fail-safe backup for the XBL.
The rest of the boot chain is stored in LUN4.
The LUN6 and LUN7 are unused by default.

​UFS device partition layout

UFS device partition layout