TUSB9260

SLLS962 – DECEMBER 2009

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When connected as a SuperSpeed device, the firmware presents the UASP interface as the primary

interface, and the BOT interface as a secondary interface. If the host stack is not UASP aware, it can

enable the BOT interface using a SET_INTERFACE request for alternate interface 1.

When connected as a high-speed or full-speed device, the firmware presents the BOT interface as the

primary interface and the UASP interface as the secondary interface. If the host stack is UASP aware, it

can enable the UASP interface using a SET_INTERFACE request for alternate interface 1.

When configured for BOT, the firmware performs the following functions:

•

Receives the command block wrapper (CBW) from the OUT endpoint on the USB interface.

•

Deconstructs the encapsulated command in the CBW and creates the appropriate command table

(CT) entry, including the physical region descriptor table (PRDT), as necessary for the AHCI to deliver

command to the SATA device.

•

Performs management as required for delivery of the command response received from the SATA

device, including data for read commands, as packet data to the USB bulk transfer pipe. This includes

setting up TRBs for the USB device controller.

•

Performs management as required for delivery of packet data for write commands from the USB bulk

interface pipe to the SATA device. This includes setting up the TRBs for the device controller.

•

Creates the command list (CL) entry pointing to the CT entry and enable the command slot for delivery

of the command from the AHCI to the SATA device.

•

Creates the command status wrapper (CSW) for each CBW received for delivery to the USB host on

the IN endpoint.

•

Monitors for error conditions per the 13 cases (defined in the BOT specification).

•

Performs other necessary operations, including hardware initialization or manipulation of GPIOs, to

support device activity indication, hot plug, media notifications, one-touch back up if supported, or other

required functionality.

When the UASP configuration is enabled, the firmware performs the following functions:

•

Receives the command information units (IU) from the command OUT endpoint on the USB interface.

•

Creates the appropriate command table (CT) entry based on the received command IU, including the

physical region descriptor table (PRDT), as necessary for the AHCI to deliver command to the SATA

device.

–

Performs management as required for delivery of the command response IU received from the

SATA device, this includes read ready IU, write ready IU, and response IU. These are delivered on

the status IN endpoint. This includes setting up TRBs on the USB device controller. Note, when

operating in SuperSpeed mode the device does not have to return the read ready IU or write ready

IU if it returns ERDY with the initiator port transfer tag (see the UAS specification) as the stream ID.

–

Performs management as necessary to deliver data from target for read commands, on the DFT IN

endpoint. This includes setting up TRBs on the USB device controller.

–

Performs management as required for delivery of packet data from initiator for write commands

from the DFI OUT endpoint to the SATA device. This includes setting up TRBs on the USB device

controller.

•

Creates the command list (CL) entry pointing to the CT entry and enable the command slot for delivery

of the command from the AHCI to the SATA device. This includes maintaining a list of command tags

and associated command slots.

•

Monitors for error conditions and provide appropriate status.

•

Performs other necessary operations, including hardware initialization or manipulation of GPIOs, to

support device activity indication, hot plug, media notifications, one-touch back up if supported, or other

required functionality.

8

Overview

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