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Improving Networks Worldwide.
UNH InterOperability Lab
SATA Chapters 11 and 12Device Command Layer Protocols
2
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and Device)
• Other Command Layer Protocols
3
SATA Device Command Layer Protocols
Command Layer Protocols
• Series of inter-related state machines
• Guidelines for devices and hosts on steps to take when processing and incoming or outgoing command
4
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
5
SATA Device Command Layer Protocols
Power-on and COMRESET
• On reception of COMRESET from a Host, devices shall execute the hardware reset protocol regardless of current device command layer state or power management state
• Covers the basic power on procedures to be used by both Packet and Non-packet devices
6
SATA Device Command Layer Protocols
Power-on and COMRESET
• DHR0: Hardware_reset_asserted– Command Layer has received a
message from the Transport Layer that a COMRESET has been asserted
– Device stays in this state until message from Phy State Machine is received saying that the hardware reset has been negated
– Only transitions to DHR1
7
SATA Device Command Layer Protocols
Power-on and COMRESET
• DHR1: Execute_diagnostics– During this state, a Device
initializes its hardware and executes its power up diagnostic routines
– Upon completion of power up diagnostic routines a Device can transition to DHR2 or DHR3
8
SATA Device Command Layer Protocols
Power-on and COMRESET
• DHR2: Send_good_status– In this state, a Devices transmits
a Register FIS to the Host indicating that the power up diagnostics have been completed successfully
– The Device then transitions to DI0: Device_idle
9
SATA Device Command Layer Protocols
Power-on and COMRESET
• DHR3: Send_bad_status– In this state, a Devices transmits
a Register FIS to the Host indicating that the power up diagnostics have NOT been completed successfully
– The Device then transitions to DI0: Device_idle
10
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
11
SATA Device Command Layer Protocols
Device Idle Protocol
• The default state for all SATA Devices
– Awaiting the reception of a FIS from the Host
– State machine defines how to process commands and how to decide which command specific state machine to enter based on the received FIS
12
SATA Device Command Layer Protocols
Device Idle Protocol
• DI0: Device Idle– Default State– Just waiting for something to
happen from the Host– Numerous possible transitions
from this state based on Host actions
13
SATA Device Command Layer Protocols
Device Idle Protocol
• DI1: Check_FIS– Entered from DI0 upon reception
of a FIS– Check C-bit and SRST-Bit of the
FIS• If C-bit asserted → DI2:
Check_command• If SRST-bit asserted → DSR0:
Software_reset_asserted
– Any other FIS → DI0: Device_idle
14
SATA Device Command Layer Protocols
Device Idle Protocol
• DI2: Check_command– Check the fields of the command– 15 possible transitions out of this
state based on the command type found when checking fields
15
SATA Device Command Layer Protocols
Device Idle Protocol• DI3: No_Command
– Entered when a Device receives a command not supported
– ABRT-bit of command set to one → DI0: Device_idle
• DI4: Set_service– Entered when Device is ready to
complete data transfer for a queued command
– SERV-bit of command set to one → DI0: Device_idle
16
SATA Device Command Layer Protocols
Device Idle Protocol
• DI5: Service_test– Entered when a SERVICE
Command is received– Check the command to see if a
Register FIS needs to be transmitted for DRQ bit and to set the Tag
– If PACKET PIO In/Out → DI7: Service_decode
– Else → DI6: Service_send_tag
17
SATA Device Command Layer Protocols
Device Idle Protocol
• DI6: Service_send_tag– Entered when a SERVICE
command has been received– Device waits for a Register FIS
with the BSY-bit de-asserted, DRQ-bit asserted, and an appropriate tag
– Upon reception of the FIS → DI7: Service_decode
18
SATA Device Command Layer Protocols
Device Idle Protocol
• DI7: Service_Decode– Check the command that has
been received after the required Register FIS has been received
– 6 Possible transitions based on the command type
19
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
20
SATA Device Command Layer ProtocolsExecute Device Diagnostics
Protocol• Command Class for the EXECUTE
DEVICE DIAGNOSTIC command– If COMRESET or a FIS with SRST-
bit asserted is received, the Device shall execute the COMRESET Command Protocol or the Software Reset Command Protocol respectively
• Describes the process for EXECUTE DEVICE DIAGNOSTIC command
21
SATA Device Command Layer ProtocolsExecute Device Diagnostics
Protocol• DEDD0: Execute_device_diag
– In this state, a Device will execute its internal diagnostic procedures
• If diagnostics completed successfully → DEDD1: Send_good_status
• Else → DEDD2: Send_bad_status • From DEDD1 and DEDD2 → DI0:
Device_Idle
22
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
23
SATA Device Command Layer Protocols
Device Reset Protocol
• Command Class for the DEVICE RESET command
– If COMRESET or a FIS with SRST-bit asserted is received, the Device shall execute the COMRESET Command Protocol or the Software Reset Command Protocol respectively
• When this command is received, a Device will stop all activity
24
SATA Device Command Layer Protocols
Device Reset Protocol• DDR0: Device_reset
– Upon reception of this command, a Device will halt all execution of any outstanding commands and will hald all background activity
– When activity has ceased → DDR1: Send_good_status
• DDR1: Send_good_status– Device requests the Host transmit a
Register FIS– Upon reception of this FIS → DI0:
Device_Idle
25
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
26
SATA Device Command Layer Protocols
DMA Data-in Protocol
• Command Class for the READ DMA and READ DMA EXT commands
• Execution of this command induces the transfer of one ore more blocks of data from the device to the host use using a DMA transfer
• Command Protocol for most read operations in modern, non-packet devices
27
SATA Device Command Layer Protocols
DMA Data-in Protocol
• DDMAI0: DMA_in– In this state, a Device will prepare
the date for transfer to the host – When Data FIS is ready →
DDMAI1: Send_data– Otherwise, command has been
completed or aborted → DDMA2: Send_status
28
SATA Device Command Layer Protocols
DMA Data-in Protocol
• DDMAI1: Send_data– In this state, the Device shall
transmit the prepared FIS to the host
• DDMAI2: Send_status– A Device enters this state when
all the data for a command has been transmitted to a Host or an error has caused the command to abort
29
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and
Device)
• Other Command Layer Protocols
30
SATA Device Command Layer Protocols
FPDMA Queued Protocol
• Command Class for READ FPDMA QUEUED and WRITE FPDMA QUEUED commands
– Special Read and Write commands for Native Command Queuing features found in SATA2+
31
SATA Device Command Layer Protocols
FPDMA Queued Protocol
• DFPDMAQ1: AddCommandToQueue
– Upon determining a FPDMA command has been received, a Device will add the command to its internal queue and store the command's TAG value
– Successful en-queuing → DFPDMAQ2: CleareInterfaceBsy
– Else → DFPDMAQ12: BrokenHost_ClearBusy
32
SATA Device Command Layer Protocols
FPDMA Queued Protocol
• DFPDMAQ2: ClearInterfaceBsy– Transmit a Register FIS to the
host with BSY and DRQ bits deasserted, indicating the Device is ready to receive the next command
– Upon transmission → DI0: Device_idle
33
SATA Device Command Layer Protocols
FPDMA Queued Protocol
• DFPDMAQ3: DataPhaseReadSetup– State entered when the device is
ready to transmit data from a previously queued READ FPDMA QUEUED command
– In this state, a Device will attempt to setup up a host memory write DMA connection with the Host
– Once the connection is established, a Device will transition to DFPDMAQ8
34
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ4:
DataPhasePreWriteSetup– State entered when the device is
ready to receive data from a previously queued WRITE FPDMA QUEUED command
– In this state a Device needs to determine if Auto-Activate is supported an enabled • If yes, → DFPDMAQ5:
DataPhase_WriteSetup• Else → DFPDMAQ6:
DatePahse_OldWriteSetup
35
SATA Device Command Layer Protocols
FPDMA Queued Protocol
• DFPDMAQ5: DataPhase_WriteSetup– This state is entered when a
Device is ready to Auto-Activate– A device transmits a DMA Setup
FIS to the host with a DMA buffer Id, the queued TAG value, the direction bit cleared (Host Memory Read), and the AA bit set to one
– Once Setup FIS is completed → DFPDMAQ9: DataXmitWrite
36
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ6: DataPhase_OldWriteSetup– This state is entered when Auto-
Activate is not supported or enabled– A device transmits a DMA Setup FIS
to the host with a DMA buffer Id, the queued TAG value, the direction bit cleared (Host Memory Read), and the AA bit set to zero
– Once Setup FIS is completed → DFPDMAQ9: DataXmitWrite
37
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ7: DataPhaseXmit_Activate
– This state is entered after a device completed setup for a WRITE DPDMA QUEUED command
– While in this state a Device transmits a DMA Activate FIS indicating its readiness to receive DATA FISes
– The device then transitions to DFPDMAQ9: DataXmitWrite
38
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ8: DataXmitRead
– This state is entered after a device has completed setup for a READ FPDMA QUEUED command
– A device continues to transmit Data FISs until the command has been completed or an error has been encountered
– Device transitions to DI0: Device_idle upon completion
39
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ9: DataXmitWrite
– This state is entered after a device has completed setup for a WRITE FPDMA QUEUED command
– A device continues to receive DATA FISes until the command has been completed or an error has been encountered
– Device transitions to DI0: Device_idle upon completetion
40
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ10: SendStatus
– This state is entered after a device has completed the data transfer associated with a command
– In this state, a device will transmit a Set Device Bits FIS to the host indicating the completion of the command
– Following the transmission of this FIS, a device will transition to DI0: Device_idle
41
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ11: Error
– This state is entered when a device has encountered an unrecoverable error
– When this state is entered, a device halts all transmissions and transmits a Set Device Bits FIS to the host indictating the error condition
– A device then transitions to DFPDMAQ13: WaitforClear
42
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ12: BrokenHost_ClearBusy
– This state is entered when a device receives a READ or WRITE FPDMA QUEUED command with a tag that exists already in the queue or a non-queued command is received while there are still outstanding commands in the queue
– Upon entering this state, a device will transmit a Register FIS to the host indicating the error condition and then transition to DFPDMAQ13
43
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ13: WaitforClear
– This state is entered when a device has transmitted an error FIS and is waiting for a READ LOG EXT command or a Soft-Reset
– All other commands will be responded to with an Error FIS
– When the READ LOG EXT command is received the device shall transition to DFPDMAQ12
44
SATA Device Command Layer Protocols
FPDMA Queued Protocol• DFPDMAQ14: SendQueue_CleanACK
– This stae is entered when the Host has responseded to an error FIS with a READ LOG EXT command
– The Device will discard all queued commands remaining and transmit a Set Device Bits FIS with the ERR bit cleared, Error Field cleared, and Sactive = FFFFFFFFh and interup cleared
– Upon transmission of this FIS, the device shall transition to DPIOI0:PIO_in
45
SATA Device Command Layer ProtocolsFPDMA Queued Protocol
(Hosts)• This state machine describes the
behavior for Native Command Queuing Hosts
• This class is largely similar to the behavior of the devices but also covers:
– TAG assignment – Error Recovery– Retrying Failed Commands
46
SATA Device Command Layer Protocols
Presentation Topics
• Device Command Layer Protocol– Power-on and COMRESET– Device Idle– EXECUTE DEVICE DIAGNOSITC– DEVICE RESET– DMA data-in– FPDMA QUEUED (Host and Device)
• Other Command Layer Protocols
47
SATA Device Command Layer Protocols
Software Reset Protocol
• This state machine covers how a device handles receiving a FIS with the SRST bit asserted
• Essentially the same as the DEVICE RESET Command Protocol
48
SATA Device Command Layer Protocols
Non-Data Protocol
• This state machine describes how a device will handle receiving a non-data command FIS
• Commands include: FLUSH CACHE, IDLE, MEDIA LOCK, SEEK, NOP, and SET MULTIPLE MODE among others
49
SATA Device Command Layer ProtocolsPIO Data-in and Data-out
Protocol• These two state machines describe how
commands will responds to PIO requests (Diagnostic and legacy commands from previous ATA standards)
• Commands include IDENTIFY DEVICE, READ SECTORS, SMART READ DATA, DOWNLOAD MICROCODE, and WRITE SECTORS among others
50
SATA Device Command Layer Protocols
Packet Protocol
• This state machine describes how a device will handle receiving a packet based commands. Packet commands are used by Optical Disc Drives and other ATAPI device which do not utilize the traditional PIO and DMA interfaces defined with ATA