Ex_Addr Value To Access Exp_Inbound_Addr Register - Intel IXP45X Developer's Manual

Expansion Bus Controller—Intel
Processors
Table 235.

EX_ADDR Value to Access EXP_INBOUND_ADDR Register

AddrWidth
0x8
0x9
0xA
0xB
12.5.15 EXP_LOCK0
Register Name:
Physical Address:
Register Description:
Access: See below.
3
1
Register
Bits Name
If the value of LOCK is 0x0 when read, the master owns the resource
and the Expansion bus controller will set LOCK to 0xFFFFFFFF in the
following cycle. The master owns the resource until the master writes
31:0 LOCK a 1 to any of the bits in this register to clear the lock to 0x0. If LOCK is
0xFFFFFFFF when read, the resource is locked and the master does not
own the resource and must re-read this register again to lock the
resource.
The intent of the EXP_LOCK0 register is to provide multiple masters a mechanism to
lock some arbitrary hardware resource such as a particular region in DDR address
space. When the EXP_LOCK0 register is read for the first time, the Expansion bus
controller will return 0x0 to that master. If the value read from the EXP_LOCK0 register
is 0x0, that master will have access to the resource that was locked until that master
clears the lock by writing a '1' to any of the bits in the EXP_LOCK0 register. If another
master reads the EXP_LOCK0 register before the original master clears the lock, the
2nd master will observe 0xFFFFFFFF, which means that the resource is locked and it
does not have access to the resource. The IXP45X/IXP46X network processors do not
have any hardware to prevent the 2nd master from accessing the locked resource and
it is up to software to ensure that the 2nd master complies to this protocol. The 2nd
master will continue to poll EXP_LOCK0 until it owns the lock (observes 0x0). Once the
2nd master is completed with the lock, it clears the lock to allow another master to
obtain the locked resource. Only the master that owns the lock should be writing the
EXP_LOCK0 register to clear the lock. Other masters must not write the EXP_LOCK0
register when it does own the lock.
August 2006
Order Number: 306262-004US
® ®
IXP45X and Intel IXP46X Product Line of Network
EX_ADDR[3:0] to read/
write
EXP_INBOUND_ADDR
"01XX"
"01XX"
"01XX"
"01XX"
0xC4000108 and
from External
Master (See note
below)
This register is intended to facilitate resource locking for multiple masters
Description
Intel
EX_ADDR[19:4] to read/
write
EXP_INBOUND_ADDR
0x0000
0x0000
0x0000
0x0000
EXP_LOCK0
Reset Hex Value:
LOCK
EXP_LOCK0
® ®
IXP45X and Intel IXP46X Product Line of Network Processors
EX_ADDR[24:20] to read/
write
EXP_INBOUND_ADDR
"10000"
"X1000"
"XX100"
"XXX10"
0x00000000
1 0
Reset
Access
Value
0x0 RS/W1C
Developer's Manual
719