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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.
Serial RapidIO (SRIO)
48
SPRUE13A – September 2006
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