Kontron AM4901 IPMI - Manual (Page 20)

IPMI Firmware User Guide AM5901/AM4901
Page 20 ID: 1035-8760, Rev. 3.0
3.5 E-Keying
In order to ensure proper operation of the AMC modules in the system, the topology of the em-
ployed backplane must support the required connectivity. The MCH’s E-keying process re-
quires during the activation and deactivation of AMC modules that the module’s line drivers be
switched electronically on and off. The switch-on takes place before each AMC module is sup-
plied with payload power (so called “early E-keying”).
The FRU data of supported AMC modules may contain a maximum of:
• 16 AMC channel descriptors
• 22 AMC link descriptors
• 4 AMC Clock descriptors
If this amount is exceeded, no ports of the affected AMC modules will be enabled.
3.5.1 FCLKA E-Keying
The MCH being described here is not able to supply the clock for PCI Express (CLK3/FCLKA).
This clock must be supplied by the backplane or an AMC module.
The MCH has three different strategies to be able to work in all possible clock environments.
The option "fclockMode" in the environmental options rules the MCH's behavior during Fclock
e-keying.
When the MCH identifies the type of rack or backplane respectively where it is running it auto-
matically adjusts the "fclockMode" options in the "environmental options" in case the environ-
mental options are not yet 'locked'. Please refer to chapter "Environmental Options/Defaults"
where the possible "fclockMode" modes are listed which can be set depending on the rack or
backplane type.
The "fclockMode" may be set manually as well, e.g. by CLI command 'eopts' or CLI command
'fclockopts', and can be protected against undesired automatic changing by setting the 'locked'
bit if required.
Examples for CLI:
• 'fclockopts spec'
• 'fclockopts rack'
• 'fclockopts manu'
Please note that a manual change of "fclockMode" should only take place when no AMC is ac-
tivated.
There are three different "fclockMode" modes defined (which one is currently set is showed e.g.
by the CLI command 'fclockopts'):
• 'spec': An AMC/uTCA specification compliant Fclock e-keying will be performed. This
means that any Fclock being offered by the backplane is ignored. Only the "Carrier Clock
Point-to-Point Connectivity Records" (refer to AMC.0 R2.0 3.9.2.2 Table 3-29) being of-
fered by the backplane and the "Direct Clock Descriptors" (refer to AMC.0 R2.0 3.9.2.3
Table 3-38) being offered by the AMC modules will be processed. If two AMC modules
become activated and their Fclocks lines are connected by the backplane and there is a
source/receiver pair of clock descriptors then their clock ports will be enabled.