UFS_DEVICE_DESCRIPTOR structure (ufs.h)
UFS_DEVICE_DESCRIPTOR is the main descriptor for Universal Flash Storage (UFS) devices and should be the first descriptor retrieved as it specifies the device class and sub-class and the protocol (command set) to use to access this device and the maximum number of logical units contained within the device.
Syntax
typedef struct {
UCHAR bLength;
UCHAR bDescriptorIDN;
UCHAR bDevice;
UCHAR bDeviceClass;
UCHAR bDeviceSubClass;
UCHAR bProtocol;
UCHAR bNumberLU;
UCHAR bNumberWLU;
UCHAR bBootEnable;
UCHAR bDescrAccessEn;
UCHAR bInitPowerMode;
UCHAR bHighPriorityLUN;
UCHAR bSecureRemovalType;
UCHAR bSecurityLU;
UCHAR bBackgroundOpsTermLat;
UCHAR bInitActiveICCLevel;
UCHAR wSpecVersion[2];
UCHAR wManufactureDate[2];
UCHAR iManufacturerName;
UCHAR iProductName;
UCHAR iSerialNumberID;
UCHAR iOemID;
UCHAR wManufacturerID[2];
UCHAR bUD0BaseOffset;
UCHAR bUDConfigPLength;
UCHAR bDeviceRTTCap;
UCHAR wPeriodicRTCUpdate[2];
UCHAR bUFSFeaturesSupport;
UCHAR bFFUTimeout;
UCHAR bQueueDepth;
UCHAR wDeviceVersion[2];
UCHAR bNumSecureWPArea;
UCHAR dPSAMaxDataSize[4];
UCHAR dPSAStateTimeout;
UCHAR iProductRevisionLevel;
UCHAR Reserved[5];
UCHAR Reserved2[16];
USHORT wHPBVersion;
UCHAR bHPBControl;
UCHAR Reserved3[12];
UCHAR dExtendedUFSFeaturesSupport[4];
UCHAR bWriteBoosterBufferPreserveUserSpaceEn;
UCHAR bWriteBoosterBufferType;
UCHAR dNumSharedWriteBoosterBufferAllocUnits[4];
} UFS_DEVICE_DESCRIPTOR, *PUFS_DEVICE_DESCRIPTOR;
Members
bLength
Specifies the length, in bytes, of this descriptor.
bDescriptorIDN
Specifies the type of the descriptor. This descriptor will have a value of UFS_DESC_DEVICE_IDN.
bDevice
Specifies the device type.
| Value | Description |
|---|---|
| 0x00 | Device |
| All other values | Reserved for future use |
bDeviceClass
Specifies the device class.
| Value | Description |
|---|---|
| 0x00 | Mass Storage |
| All other values | Reserved for future use |
bDeviceSubClass
Specifies the UFS mass storage subclasses in a bit map as follows:
| Bit | Value |
|---|---|
| 0 | Bootable / Non-Bootable |
| 1 | Embedded / Removable |
| 2 | Reserved for JESD220-1 (UME) |
| All other values | Reserved for future use |
bProtocol
Specifies the protocol support by the UFS device.
| Value | Description |
|---|---|
| 0x00 | SCSI |
| All other values | Reserved for future use |
bNumberLU
Specifies the number of Logical Units. This does not include the number of well known logical units.
bNumberWLU
Specifies the number of well known logical units.
bBootEnable
Specifies if a device's boot feature is enabled.
| Value | Description |
|---|---|
| 0x00 | Boot feature disabled |
| 0x01 | Boot feature enabled |
| All other values | Reserved for future use |
bDescrAccessEn
Indicates whether the Device Descriptor can be read after the partial initialization phase of the boot sequence.
| Value | Description |
|---|---|
| 0x00 | Device Descriptor access disabled |
| 0x01 | Device Descriptor access enabled |
| All other values | Reserved for future use |
bInitPowerMode
bInitPowerMode defines the Power Mode after device initialization or hardware reset.
| Value | Description |
|---|---|
| 0x00 | UFS-Sleep mode |
| 0x01 | Active-mode |
| All other values | Reserved for future use |
bHighPriorityLUN
bHighPriorityLUN defines the high priority logical unit.
bSecureRemovalType
Specifies the secure removal type.
| Value | Description |
|---|---|
| 0x00 | Information removed by an erase of the physical memory |
| 0x01 | Information removed by overwriting the addressed locations with a single character followed by an erase |
| 0x02 | Information removed by overwriting the addressed locations with a character, its complement, then a random character |
| 0x03 | Information removed using a vendor defined mechanism. |
| All other values | Reserved for future use |
bSecurityLU
Specifies if there is support for security LU's
| Value | Description |
|---|---|
| 0x00 | Not supported |
| 0x01 | Replay Protected Memory Block (RPMB) |
| All other values | Reserved for future use |
bBackgroundOpsTermLat
bBackgroundOpsTermLat defines the maximum latency for starting data transmission when background operations are ongoing. The termination latency limit applies to two cases:
- When the device receives a COMMAND UFS Protocol Information Units (UPIU) with a transfer request. The device shall start the data transfer and send a DATA IN UPIU or a RTT UPIU within the latency limit.
- When the device receives QUERY REQUEST UPIU to clear the fBackgroundOpsEn Flag. The device is expected to terminate background operations within the latency limit.
bInitActiveICCLevel
bInitActiveICCLevel defines the bActiveICCLevel value after power on or reset. The range of the value is from 0x00 to 0x0F.
wSpecVersion[2]
Indicates the specification version in Binary Coded Decimal (BCD) format.
wManufactureDate[2]
Specifies the manufacturing date in BCD format as 0xMMYY.
iManufacturerName
Contains an index value to the string which contains the manufacturer's name.
iProductName
Contains an index value to the string which contains the product's name.
iSerialNumberID
Contains an index value to the string which contains the serial's number.
iOemID
Contains an index value to the string which contains the OEM ID.
wManufacturerID[2]
Specifies the Manufacturer ID of the device.
bUD0BaseOffset
Specifies the Offset of Unit Descriptor 0's configurable parameters within the Configuration Descriptor, UFS_CONFIG_DESCRIPTOR.
bUDConfigPLength
Total size of a UFS_UNIT_CONFIG_DESCRIPTOR's parameters.
bDeviceRTTCap
Specifies the maximum number of outstanding READY TO TRANSFER UPIU'S supported by device. The minimum value is 2.
wPeriodicRTCUpdate[2]
Specifies the frequency and method of real-time clock updates. Bits 10 to 15 are reserved.
bUFSFeaturesSupport
Specifies which features are supported on this device. A feature is supported if its related bit is set to 1.
| Bit | Value |
|---|---|
| 0 | Field Firmware Update (FFU) |
| 1 | Production State Awareness (PSA) |
| 2 | Device Life Span |
| All other values | Reserved for future use |
bFFUTimeout
The maximum time, in seconds, to which access to the device is limited or not possible through any ports associated due to execution of a WRITE BUFFER command.
bQueueDepth
Specifies the queue depth. If this member is equal to 0, the device implements the per-LU queuing architecture.
wDeviceVersion[2]
Specifies the device version.
bNumSecureWPArea
Specifies the total number of Secure Write Protect Areas supported by the device. The value of this member is between bNumberLU and 32.
dPSAMaxDataSize[4]
Specifies the maximum amount of data that can be written during the pre-soldering phase of the PSA flow.
dPSAStateTimeout
This member corresponds to bPSAStateTimeout (29h) in the JEDEC specification.
iProductRevisionLevel
Specifies the index to the string which contains the Product Revision Level.
Reserved[5]
Reserved for future use.
Reserved2[16]
Reserved for future use.
wHPBVersion
bHPBControl
Reserved3[12]
dExtendedUFSFeaturesSupport[4]
bWriteBoosterBufferPreserveUserSpaceEn
bWriteBoosterBufferType
dNumSharedWriteBoosterBufferAllocUnits[4]
Remarks
If bBootEnable in the UFS_DEVICE_DESCRIPTOR is set to zero or if the Boot well known logical unit is not mapped to an enabled logical unit, then the Boot well known logical unit shall terminate.
UFS_DEVICE_DESCRIPTOR is read only, some of its parameters may be changed by changing the corresponding parameter in UFS_UNIT_CONFIG_DESCRIPTOR.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 10, version 1709 |
| Minimum supported server | Windows Server 2016 |
| Header | ufs.h |
See also
Feedback
Coming soon: Throughout 2024 we will be phasing out GitHub Issues as the feedback mechanism for content and replacing it with a new feedback system. For more information see: https://aka.ms/ContentUserFeedback.
Submit and view feedback for