Intel
®
81341 and 81342—Messaging Unit
Intel
®
81341 and 81342 I/O Processors
Developer’s Manual
December 2007
434
Order Number: 315037-002US
4.9.9
Inbound Reset Control and Status Register - IRCSR
The Inbound Reset Control and Status Register (IRCSR) provides the ability for the
Host processor to request a Selective Reset or a Coordinate Reset. A selective reset is
used to perform a soft reset. A selective reset is requested by the host processor
setting the Selective Reset bit of the IRCSR, which causes an Intel XScale
®
processor
interrupt.
A coordinated reset is used when supporting multiple PCI functions. In a multi-function
scenario, before the Host driver can issue a hardware reset via one of the PCI
functions, all the host drivers running must be quiesced. A coordinated reset is
requested by the host processor setting the Coordinated Reset bit in the IRCSR, which
causes an Intel XScale
®
processor interrupt. After all the host drivers have been
quiesced, the host driver that initiated the coordinated reset would request a hardware
reset of the 81341 and 81342. When the host driver sets both the Selective Reset and
Coordinated Reset bits simultaneously, an internal bus reset is initiated.
Note:
An internal bus reset event that is caused by setting both the CR and SR bits of the
IRCSR is indicated in the Reset Cause and Status Register (RCSR). For example, after
an internal bus reset the cause of the internal bus reset can be identified by reading the
RCSR. Refer to the
Chapter 6.0, “System Controller (SC) and Internal Bus Bridge”
for
detailed descriptions of the RCSR register.
Table 273. Inbound Reset Control and Status Register - IRCSR
Bit
Default
Description
31:02
00000000H Reserved.
01
0
2
Coordinated Reset (CR) - This bit is valid when the 81341 and 81342 implements Multi-Function Reset
protocol, (MF=1, bit 1 in the ORCSR). A Host driver writes a one into this bit to request a Coordinated
Reset. Writing a 1 to the CR bit would generate an interrupt to the Intel XScale
®
processor. However,
writing 1’s to the CR bit and the SR bit simultaneously would instead generate an internal bus reset. In
a Coordinated Reset (only CR bit set), each function is notified and acknowledges the internal bus reset
before it actually occurs. In an internal bus reset, the reset proceeds immediately without any
notification to the any of the other Hosts.
00
0
2
Selective Reset (SR) - The Host driver sets this bit in order to request a firmware state and structures
re-initialization. Setting this bit generates an interrupt to the Intel XScale
®
processor. However, writing
1’s to the CR bit and the SR bit simultaneously would instead generate an internal bus reset. Setting the
SR bit by itself does not generate an internal bus reset. Therefore, the Intel XScale
®
processor must be
operational for the reset to be processed. Setting this bit has no impact on any other functions on 81341
and 81342.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rv
rc
rw
rc
rw
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
MU/PCI Base Address Offset
OIMR: 0038H
internal bus address offset
OIMR: 4038H