Texas Instruments TMS320TCI648x manual DSP core uses this bit to reclaim buffers

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SRIO Functional Description

	Table 18. RX Buffer Descriptor Field Descriptions (continued)
Field	Description
ownership	Ownership: Indicates ownership of the message and is valid only on sop. This bit is set
	by the DSP core and cleared by the port when the message has been transmitted. The
	DSP core uses this bit to reclaim buffers.
	0: The message is owned by the DSP core
	1: The message is owned by the port
eoq	End Of Queue: Set by the port to indicate that the RX queue empty condition exists.
	This bit is valid only on eop. The port determines the end of queue condition by a zero
	next_descriptor_pointer.
	0: The RX queue has more buffers available for reception.
	1: The Descriptor buffer is the last buffer in the last message in the queue.
teardown_complete	Teardown Complete: Set by the port to indicate that the host commanded teardown
	process is complete, and the channel buffers may be reclaimed by the host.
	0: The port has not completed the teardown process.
	1: The port has completed the commanded teardown process.
message_length	Message Length: Initially written by the DSP core to specify the maximum number of
	double-words the buffer can receive. Updated by the peripheral (after receiving a
	message) to indicate the actual number of double-words in the entire message.
	Message payloads are limited to a maximum size of 512 double-words (4096 bytes).
	000000000b: 512 double words
	000000001b: 1 double word
	000000010b: 2 double words
	. . .
	111111111b: 511 double words
src_id	Source Node ID: Unique node identifier of the source of the message. Written by the
	DSP core.
tt	RapidIO tt field specifying 8- or 16-bit DeviceIDs. Written by the DSP core.
	00b: 8-bit deviceIDs
	01b: 16-bit deviceIDs
	10: reserved
	11: reserved
pri	Message Priority: Specifies the SRIO priority at which the message was sent. Written
	by the DSP core.
cc	Completion Code: Written by the port.
	000: Good completion. Message received.
	001: Error, RX message length greater than supported buffer descriptor
	message_length
	010: Error, TimeOut on receiving one of the segments
	011: DMA transfer error on one or more segments
	100: Queue teardown completed, data invalid
	101: 111 Reserved
mailbox	Destination Mailbox: Specifies the mailbox to which the message was sent. Written by
	the DSP core.
	000000b: Mailbox 0
	000001b: Mailbox 1
	. . .
	000100b: Mailbox 4
	. . .
	111111b: Mailbox 63
	For multi-segment messages, only the two LSBs of this mailbox are valid. Hardware
	ignores the four MSBs if the incoming message has multiple segments.

48 Serial RapidIO (SRIO) SPRUE13A –September 2006

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