8 ohci registers – Texas Instruments Dual/Single Socket CardBus and UntraMedia Controller PCI7621 User Manual
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8−1
8 OHCI Registers
The OHCI registers defined by the 1394 Open Host Controller Interface Specification are memory-mapped into a
2K-byte region of memory pointed to by the OHCI base address register at offset 10h in PCI configuration space (see
Section 7.8). These registers are the primary interface for controlling the PCI7x21/PCI7x11 IEEE 1394 link function.
This section provides the register interface and bit descriptions. Several set/clear register pairs in this programming
model are implemented to solve various issues with typical read-modify-write control registers. There are two
addresses for a set/clear register: RegisterSet and RegisterClear. See Table 8−1 for a register listing. A 1 bit written
to RegisterSet causes the corresponding bit in the set/clear register to be set to 1; a 0 bit leaves the corresponding
bit unaffected. A 1 bit written to RegisterClear causes the corresponding bit in the set/clear register to be cleared;
a 0 bit leaves the corresponding bit in the set/clear register unaffected.
Typically, a read from either RegisterSet or RegisterClear returns the contents of the set or clear register, respectively.
However, sometimes reading the RegisterClear provides a masked version of the set or clear register. The interrupt
event register is an example of this behavior.
Table 8−1. OHCI Register Map
DMA CONTEXT
REGISTER NAME
ABBREVIATION
OFFSET
—
OHCI version
Version
00h
GUID ROM
GUID_ROM
04h
Asynchronous transmit retries
ATRetries
08h
CSR data
CSRData
0Ch
CSR compare
CSRCompareData
10h
CSR control
CSRControl
14h
Configuration ROM header
ConfigROMhdr
18h
Bus identification
BusID
1Ch
Bus options ‡
BusOptions
20h
GUID high ‡
GUIDHi
24h
GUID low ‡
GUIDLo
28h
Reserved
—
2Ch−30h
Configuration ROM mapping
ConfigROMmap
34h
Posted write address low
PostedWriteAddressLo
38h
Posted write address high
PostedWriteAddressHi
3Ch
Vendor ID
VendorID
40h
Reserved
—
44h−4Ch
Host controller control ‡
HCControlSet
50h
Host controller control ‡
HCControlClr
54h
Reserved
—
58h−5Ch
‡ One or more bits in this register are cleared only by the assertion of GRST.