Sitd Buffer Pointer List (Plus); Sitd Back Link Pointer - Intel IXP45X Developer's Manual

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Table 153. siTD Transfer Status and Control (Sheet 2 of 2)
Bit
2
1
0
9.13.4.4

siTD Buffer Pointer List (Plus)

DWords 4 and 5 are the data buffer page pointers for the transfer. This structure
supports one physical page cross. The most significant 20 bits of each DWord in this
section are the 4K (page) aligned buffer pointers. The least significant 12 bits of each
DWord are used as additional transfer state.
Table 154. Buffer Page Pointer List (Plus)
Bit
31:12
11:0
9.13.4.5

siTD Back Link Pointer

DWord 6 of a siTD is simply another schedule link pointer. This pointer is always zero,
or references a siTD. This pointer cannot reference any other schedule data structure.
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Intel IXP45X and Intel IXP46X Product Line of Network Processors
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IXP45X and Intel IXP46X Product Line of Network Processors—USB 2.0 Host Controller
Missed Micro-Frame. The host controller detected that a host-induced hold- off caused the host
controller to miss a required complete-split transaction.
Split Transaction State (SplitXstate). The bit encodings are:
Value Meaning
00b Do Start Split. This value directs the host
endpoint when a match is encountered in
01b Do Complete Split. This value directs the
transaction to the endpoint when a match is encountered in the C-mask.
(Reserved). Bit reserved for future use and should be zero.
Buffer Pointer List. Bits [31:12] of DWords 4 and 5 are 4K paged aligned, physical
memory addresses. These bits correspond to physical address bits [31:12] respectively.
The lower 12 bits in each pointer are defined and used as specified below. The field P
specifies the current active pointer
Page 0:
Current Offset. The 12 least significant bits of the Page 0 pointer is the current byte offset
for the current page pointer (as selected with the page indicator bit (P field)). The host
controller is not required to write this field back when the siTD is retired (Active bit
transitioned from a one to a zero). The least significant bits of Page 1 pointer is split into
three sub-fields
Page 1:
11:5 (Reserved).
Transaction position (TP). This field is used with T-count to determine
whether to send all, first, middle, or last with each outbound transaction
payload. System software must initialize this field with the appropriate
starting value. The host controller must correctly manage this state
during the lifetime of the transfer. The bit encodings are:
Value
00b
4:3
transaction (that is, less than or equal to 188 bytes).
01b
that is greater than 188 bytes.
10B
that is larger than 188 bytes.
11b
that was larger than 188 bytes.
Transaction count (T-Count). Software initializes this field with the
2:0 number of OUT start-splits this transfer requires. Any value larger than 6
is undefined.
Description
controller to issue a Start split transaction to the
the S-mask.
host controller to issue a Complete split
Description
Meaning
All. The entire full-speed transaction data payload is in this
Begin. This is the first data payload for a full-speed transaction
Mid. This is the middle payload for a full-speed OUT transaction
End. This is the last payload for a full-speed OUT transaction
August 2006
Order Number: 306262-004US