ALXD800EEXJ2VD AMD (ADVANCED MICRO DEVICES), ALXD800EEXJ2VD Datasheet - Page 47

• Manufacturer Part Number: ALXD800EEXJ2VD
• Manufacturer: AMD (ADVANCED MICRO DEVICES)

Specifications of ALXD800EEXJ2VD

• Operating Temperature (min): 0C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Lead Free Status / RoHS Status: Compliant

GeodeLink™ Interface Unit
4.1.2
There are some exceptions to the port addressing rules.
If a module accesses an MSR from within its closest GLIU
(e.g., CPU Core accessing a GLIU0 MSR), then, by con-
vention, the port address should be 0.0.0.0.0.0. But this
port address accesses an MSR within the source module
and not the GLIU as desired. To get around this, if the port
address contains a 0 in the first channel field and then con-
tains a 1 in any of the other channel fields, the access goes
to the GLIU nearest the module sourcing the cycle. By con-
vention, set the MSB of the second channel field,
0.4.0.0.0.0. If the MSR access is to a GLIU farther removed
from the module sourcing the cycle, then there is no con-
vention conflict, so no exception is required for that situa-
tion.
If a module attempts to access an MSR to the channel that
it is connected to, a GLIU error results. This is called a
reflective address attempt. An example of this case is the
CPU Core accessing 3.0.0.0.0.0. Since the CPU Core is
connected to Channel 3 of GLIU0, the access causes a
reflective address error. This exception is continued to the
next GLIU in the chain. The CPU Core accessing
2.1.0.0.0.0 also causes a reflective address error.
To access modules in the Geode companion device, the
port address must go through the GLPCI (PCI controller) in
the Geode LX processor and through the GLPCI in the
companion device. The port address of the MSRs in the
Geode LX processor’s GLPCI when accessed from the
CPU Core is 2.4.0.0.0.0. To get the port address to go
through the GLPCI, the third field needs a non-zero value.
By convention, this is a 2. We now have a port address of
2.4.2.0.0.0. But this accesses the MSRs in the GLPCI in
the companion device. The port to be accessed must be
added in the fourth field, 2.4.2.5.0.0, to access the AC97
audio bus master, for example.
To access the GLIU in the companion device, the same
addressing exception occurs as with GLIU0 due to the
GLPCI’s address. A port address of 2.4.2.0.0.0 accesses
the companion device’s GLPCI, not the GLIU. To solve
this, a non-zero value must be in at least one of the two
right-most port fields. By convention, a 4 in the left-most
port field is used. To access the companion device’s GLIU
from the CPU Core, the port address is 2.4.2.0.0.4.
Table 4-2 shows the MSR port address to access all the
modules in a Geode LX processor/CS5536 system with the
CPU Core as the source module. Included in the table is
the MSR port address for module access using the GLCP
and GLPCI as the source module. However, under normal
operating conditions, accessing MSRs is from the CPU
Core. Therefore, all MSR addresses in the following chap-
ters of this data book are documented using the CPU Core
as the source.
AMD Geode™ LX Processors Data Book
Port Addressing Exceptions
Note 1.
Note 2.
Note 3.
4.1.3
The GLIU decodes the destination ID of memory requests
using a series of physical to device (P2D) descriptors.
There can be up to 32 descriptors in each GLIU. The GLIU
decodes the destination ID of I/O requests using a series of
I/O descriptors (IOD).
4.1.3.1
Memory addresses are routed and optionally translated
from physical space to device space. Physical space is the
32-bit memory address space that is shared between all
GeodeLink devices. Device space is the unique address
space within a given device. For example, a memory con-
troller may implement a 4 MB frame buffer region in the 12-
16 MB range of main memory. However, the 4 MB region
may exist in the 4 GB region of physical space. The actual
location of the frame buffer in the memory controller with
respect to itself is a device address, while the address that
all the devices see in the region of memory is in physical
space.
Memory request routing and translation is performed with a
choice of five descriptor types. Each GLIU may have any
number of each descriptor type up to a total of 32. The P2D
descriptor types satisfy different needs for various software
models.
Destination
CPU Core
GLIU0
GLMC
GLIU1
GLCP
GLPCI
DC
GP
VP
VIP
Security Block
Companion
Device
The xxxx contains the lower two bits of the 18 bits from
the port fields plus the 14-bit MSR offset.
Y is the hex value obtained from one bit (always a 0) plus
the port number (#) of the six port field addresses [0+#].
Example: # = 5, therefore the Y value is [0+101] which is
5h, thus the address = 5150xxxxh.
ZK are the hex values obtained from the concatenation
of [10+#+000], where # is the port number from the six
port field address. Example # = 5, the ZK value is
[10+101+000] which is [1010,1000]. In hex. it is A8h;
thus the address is 8A80xxxxh.
Memory and I/O Mapping
Memory Routing and Translation
Table 4-2. MSR Mapping
4C00xxxxh
A000xxxxh
51Y0xxxxh
0000xxxxh
1000xxxxh
2000xxxxh
4000xxxxh
5000xxxxh
8000xxxxh
4800xxxxh
5400xxxxh
5800xxxxh
CPU Core
(Note 2)
33234C
Source (Note 1)
2C00xxxxh
8ZK0xxxxh
2000xxxxh
2400xxxxh
1000xxxxh
0000xxxxh
8000xxxxh
3000xxxxh
3400xxxxh
3800xxxxh
(Note 3)
GLCP
2C00xxxxh
2000xxxxh
2400xxxxh
1000xxxxh
6000xxxxh
0000xxxxh
3000xxxxh
3400xxxxh
3800xxxxh
GLPCI
NA
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