SATA Software Settings Preservation (SSP)

UNH InterOperability Lab

Serial Advanced Technology Attachment

(SATA)

Application Layer

Improving Networks Worldwide.

SATA Application Layer

Application Layer

• SATA Software Settings Preservation (SSP)

– Description of SSP

– SET FEATURES

– Preserved Settings Across COMRESET

• SATA Native Command Queuing (NCQ)

– How NCQ Works

– Description of NCQ

– Definitions

* SSP and NCQ are SATA specific features that were added because of increased capability. These features are often tested by OEMs and the SATA-IO certification program.

2


Description of SSP

• Host configures a device when it is recognized using commands like SET

FEATURES and SSP commands

• Software settings are retained after a software reset

• When a COMRESET occurs, not all settings are necessarily preserved as a

COMRESET is essentially a hardware reset

3


Description of SSP

• If there is an asynchronous loss of signal, a COMRESET is sent, some software settings are lost

• Without legacy mode drivers, SSP ensures that settings are maintained after a COMRESET

4


Application Layer


– Description of SSP

– SET FEATURES



– How NCQ Works


– Definitions

5


SET FEATURES

• SET FEATURES Definition

• Features Enable / Disable Values

• Feature Identification Values

1.

Enable / Disable Non-Zero Offsets in DMA Setup

2.

Enable / Disable DMA Setup FIS Auto-Activate

Optimization

3.

Enable / Disable Device-Initiated Interface Power State

Transitions

4.

Enable / Disable Guaranteed in-Order Data Delivery

5.

Enable / Disable Asynchronous Notification

6.

Enable / Disable Software Settings Preservation

7.

Enable / Disable Device Automatic Partial to Slumber

Transitions

6


SET FEATURES Definition

• SET FEATURES commands inform the device about host capabilities

• Features can be enabled and disabled

• The control of these features is designated by SET FEATURES

7


Features Enable / Disable

Values

Features(7:0)

Value

10h

Description

Enable use of Serial ATA feature

90h Disable use of Serial ATA feature

•

(7:0) contains the specific SATA feature that is being either enabled or disabled. These features are defined on the following slide.

8


Feature Identification Values

Count(7:0) Value

00h

01h

02h

03h

04h

05h

06h

07h

08h - FFh

Description

Reserved

Non-zero buffer offset in DMA Setup FIS

DMA Setup FIS Auto-Activate optimization

Device-initiated interface power state transitions

Guaranteed In-Order Data Delivery

Asynchronous Notification

Software Settings Preservation

Device Automatic Partial to Slumber transitions

Reserved for future Serial ATA definition

9


Enable / Disable Non-Zero

Offsets in DMA Setup

• Enables or disables non-zero buffer offsets in the DMA Setup FIS if device uses the First-party DMA mechanism

• When enabled, useful for completing incorrectly ordered data delivery

10


Enable / Disable DMA Setup FIS

Auto-Activate Optimization

• Used to automatically activate the transfer of the first Data FIS from the host to the device

• Allows FIS operation to immediately activate, eliminating the need for a separate DMA Activation FIS

11


Enable / Disable Device-Initiated

Interface Power State Transitions

• Allows host to enable or disable initiation of power state transitions for the device

• When interface power state transitions is favorable, host can enable for the device

12




• Capture shows device response to PMREQ_P when

IPM (Interface Power Management) is enabled

13




• Capture shows device response to PMREQ_S when

IPM (Interface Power Management) is NOT enabled

14


Enable / Disable Guaranteed in-Order Data Delivery

• Host can enable or disable guaranteed in-order data delivery when a Firstparty DMA mechanism and non-zero buffer offsets are used

• Helpful for segmenting cumbersome

I/O processes into multiple data phases while keeping complexity at a minimum

15


Enable / Disable

Asynchronous Notification

• Allows host to control asynchronous notification

• Disabled by default, when enabled allows the device to request attention without polling the host

16


Enable / Disable Software

Settings Preservation

• Software Settings Preservation can be enabled or disabled by the host

• Supported by default at start up

17


Enable / Disable Device Automatic

Partial to Slumber Transitions

• Host can enable or disable Device

Automatic Partial to Slumber transitions

• Not enabled if the Device-Initiated

Interface Power State transitions have been disabled

18


Application Layer



– SET FEATURES

– Preserved Settings Across COMRESET


– How NCQ Works


– Definitions

19


Preserved Settings Across

COMRESET

The following settings are reserved across a

COMRESET when a device has SSP enabled.

• INITIALIZE DEVICE PARAMETERS: Device settings established with the INITIALIZE DEVICE PARAMETERS command. This command is obsolete in the ATA8-ACS standard, and was last defined in the ATA/ATAPI-5 standard.

• Power Management Feature Set Standby Timer: The Standby timer used in the Power Management feature set.

• Read/Write Stream Error Log: The Read Stream Error Log and

Write Stream Error Logs (accessed using the GPL feature set commands).

20



COMRESET

• Security mode state: The security mode state established by

Security Mode feature set commands (refer to the ATA8-ACS standard). The device shall not transition to a different security mode state based on a COMRESET. For example, the device shall not transition from the SEC5: Unlocked / not Frozen state to state SEC4: Security enabled / Locked when a COMRESET occurs, instead the device shall remain in the SEC5: Unlocked / not Frozen state.

• SECURITY FREEZE LOCK: The Frozen mode setting established by the SECURITY FREEZE LOCK command.

21



COMRESET

• SECURITY UNLOCK: The unlock counter that is decrement as part of a failed SECURITY UNLOCK command attempt.

• SET MAX ADDRESS (EXT): The maximum LBA specified in

SET MAX ADDRESS of SET MAX ADDRESS EXT.

• SET FEATURES (Write Cache Enable/Disable): The write cache enable/disable setting established by the SET FEATURES command with subcommand code of 02h or 82h.

22



COMRESET

• SET FEATURES (Set Transfer Mode): PIO, Multiword, and

UDMA transfer mode settings established by the SET

FEATURES command with subcommand code of 03h.

• SET FEATURES (Advanced Power Management

Enable/Disable): The advanced power management enable/disable setting established by the SET FEATURES command with subcommand code of 05h or 85h. The advanced power management level established in the Count(7:0) register when advanced power management is enabled (SET

FEATURES subcommand code 05h) shall also be preserved.

23



COMRESET

• SET FEATURES (Read Look-Ahead): The read look-ahead enable/disable setting established by the SET FEATURES command with subcommand code of 55h or AAh.

• SET FEATURES (Release Interrupt): The release interrupt enable/disable setting established by the SET FEATURES command with a subcommand code of 5Dh or DDh.

• SET FEATURES (SERVICE Interrupt): The SERVICE interrupt enable/disable setting established by the SET FEATURES command

24



COMRESET

• SET FEATURES (Reverting to Defaults): The reverting to power-on defaults enable/disable setting established by the SET

FEATURES command with a subcommand code of CCH or 66h.

• SET MULTIPLE MODE: The block size established with the

SET MULTIPLE MODE command.

25



COMRESET

• NCQ QUEUE MANAGEMENT (Deadline Handling): The state of WDNC and RDNC.

• Write-Read-Verify feature set: The contents of IDENTIFY

DEVICE data word 120 bit 1, words 210-211, and word 220 bits

(7:0). The device shall not return to its Write-Read-verify factory default setting after processing a COMRESET

26


Application Layer



– SET FEATURES



– How NCQ Works


– Definitions

27


How NCQ Works

• When drive receives multiple commands from an application, NCQ optimizes how the commands will be completed

• Drive must intelligently and internally assess the destination of the logic block addresses and then order the commands to optimize the workload

28


How NCQ Works

• This is due to the fact that the mechanical movement needed to position the read / write head is relevant

• This improves performance and minimizes the mechanical positioning for the drive

29


How NCQ Works

• Commands are ordered in the queue to minimize mechanical movement

30


Application Layer



– SET FEATURES



– How NCQ Works

– Description of NCQ

– Definitions

31


Description of NCQ

• The reserved 32 bit field in the Set Device Bits

FIS is used to show the status for outstanding commands, one command per bit

• BSY bit in the Status register shows only if the device is ready to receive another command

32


Description of NCQ

• When a new command is received the BSY bit is set to zero

• Data sent to the device uses the First Party

DMA mechanism to allow the host to select the appropriate destination memory buffer for transfer

• Host cannot issue new commands from the reception of a DMA Setup FIS until either the the associated transfer count is exhausted OR the ERR bit in the Status register is set

33


Description of NCQ

QuickTime™ and a

decompressor are needed to see this picture.

• DMA Setup FIS for memory buffer selection

34


Description of NCQ

QuickTime™ and a


• Set Device Bits FIS for successful READ

FPDMA QUEUED command

35


Description of NCQ

QuickTime™ and a


• Set Device Bits FIS with error notification and command completions

36


Description of NCQ

QuickTime™ and a


• Set Device Bits FIS aborting all outstanding commands

37


Description of NCQ

• Successful completion of this process is updated in the Set Device Bits FIS 32 bit array

• If process fails, the process is halted and allows software or controller firmware to resolve the failure

38


Application Layer



– SET FEATURES



– How NCQ Works


– Definitions

39


Definitions

• Command Issue Mechanism

• Data Delivery Mechanism

• Status Return Mechanism

• Priority

• Unload

40


Command Issue Mechanism

• New commands can only be attempted when the BSY bit has been cleared to zero

• BSY bit in the Shadow Status register is checked before a new command is issued

• Commands are deferred if BSY bit is set to one

41



• It is favorable for a device to minimize deferred commands, so the BSY bit should be cleared as soon as possible

• NCQ issues a tag that identifies a command

• Tag range is from 0 to 31

42



• For devices that show a value less than 31 in their IDENTIFY DEVICE word 75, the host issues tags that are less than or equal to the reported value

• When a new NCQ command is issued the bit in the SActive register corresponding to the tag is set to one

43



• If command is accepted, the BSY bit is set to zero

44


Data Delivery Mechanism

• DMA Setup FIS is used by the device in order to choose the correct transfer buffer

• Multiple DMA Setup FIS transmission are not required, even if the transfer spans more than one Data FIS

45



• The DMA Mechanism is optimized to eliminate one transaction

• Requested data is immediately sent after a request without the need for a DMA Activate

FIS

46



• A device may return data for a command out of order if:

1.

Host controller supports non-zero buffering and is enabled

2.

AND if guaranteed in order data deliver is not supported OR is disabled

47



• The device may send more than one DMA

Setup FIS to complete a particular I/O process if:

1.

The host supports non-zero buffer offsets

2.

Use of non-zero offsets is enabled

3.

The device supports and has guaranteed inorder data delivery enabled

48



QuickTime™ and a


• DMA Setup FIS definition for memory buffer selection

49


Status Return Mechanism

• Is not interlocked with other commands

• Relies on one active command bit (ACT), the

32 protocol specific bits in the Set Device Bits

FIS, to convey status of outstanding commands

• SActive field conveys command completion information for updating the ACT bit array

50


Status Return Mechanism

• Possible for multiple commands to indicate completion by the time the host checks the status

• Successful commands use these mechanism to indicate status

• The Queued Error Log is used to indicate failed commands

51


Priority

• Two values for NCQ commands: normal and high

• When the host needs a higher quality of service for a command, priority is set to high

• Preference is given to high priority commands; these commands are completed in a more timely fashion than normal commands

52


Priority

• Devices do not have to process all high priority commands before normal priority commands

• However, high priority requests should be processed in a more quickly than normal isochronous requests

53


Unload

• If a device is dropped, a mechanism must be in place to park the heads when NCQ commands are still outstanding

• This could cause physical damage to the heads or disks in the hard drive. The disks could break or shatter from an impact

• If the drive is writing at the time of impact, data could be corrupted

54


Unload

• A device can accept the IDLE IMMEDIATE command with the Unload Feature. If this command is received the device shall:

1.

Unload/park the heads immediately

2.

Respond to the host with a Register - Device to

Host FIS with the ERR bit set to one in the Status register since this is a non-queued command

55


Unload

• When an error is acknowledged, the host should read the Queued Error Log to see if the error was in receiving or executing the

UNLOAD

• After the Error Log is read the NCQ error is cleared

56


Intermixing Non-Native Queued

Commands and Native Queue

Commands

• Host cannot issue a non-native queued command while a NCQ command is unfinished

• If a command is received while a NCQ command is outstanding, and error condition is sent (ERR and ABRT bits are set to one)

57


Intermixing Non-Native Queued Commands and Native Queue Commands

• All outstanding NCQ commands are aborted after an error and the device performs a clean up state

• All bits in the SActive field are set to one when the register is cleared

• After reading the error log, the device executes all queued commands regardless of errors

58


Application Layer



– SET FEATURES



– How NCQ Works


– Definitions

59

SATA Software Settings Preservation (SSP)

UNH InterOperability Lab

Enable / Disable DMA Setup FIS

Auto-Activate Optimization

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device Automatic

Partial to Slumber Transitions

Related documents

Products

Support

SATA Software Settings Preservation (SSP)

UNH InterOperability Lab

Enable / Disable DMA Setup FIS

Auto-Activate Optimization

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device-Initiated

Interface Power State Transitions

Enable / Disable Device Automatic

Partial to Slumber Transitions

Related documents

Add this document to collection(s)

Add this document to saved

Suggest us how to improve StudyLib