Kontron AM4020 IPMI Firmware - Manual (Page 44)

IPMI Firmware AM4020
Page 36 ID 1036-5671, Rev. 2.0
P R E L I M I N A R Y
9. Hot Swap
As a hot-swappable field replaceable unit (FRU), the AM4020 also follows the same stringent
carrier grade RASM feature set, namely - Reliability, Availability, Serviceability, Maintainability.
When offered in combination with AdvancedTCA platforms, TEM (Telecom Equipment Manu-
facturers) clients literally conserve valuable system AdvancedTCA system slots. The AM4020
supports full hot swap capability as per PICMG 3.0. It can be removed from or installed in the
system while it is on (without powering-down the system). Please refer to the PICMG 3.0 spec-
ification for additional details.
During hot swap of a working module, the payload side has to be shut down automatically on
command of the MMC and the end of shutdown has to be signalled back to the MMC. Because
the AM4020 supports ACPI, an OS on the payload side which supports this too makes shut-
down very easy. If the OS doesn't support ACPI, there is a special method to be used.
9.1 Method 1: The Payload OS Supports ACPI
Requirements:
• The ACPI daemon must be active.
• An ACPI power button event must result in a sleep state.
Hot swap operation sequence processed by MMC and OS:
• On command of the carrier controller, the MMC simulates the pressing and release of the
power button to force an ACPI event.
• The ACPI daemon detects this ACPI event and initiates the shutdown of the payload soft-
ware system.
• At the end of shutdown, the payload hardware system reports the sleep state to the MMC
by setting the appropriate signal line.
• The MMC detects the sleep state and reports this to the carrier controller (“quiesced”) so
that the hot swap processing can be continued and finished.
By default the MMC waits endlessly for the sleep state. Please note that some shelf managers
or MCHs use a timeout to simply switch off a module which needs too much time to reach sleep
state. As this might be an undesirable situation, refer to the appropriate manual for further as-
sistance. In any event, if an endless wait is to be avoided, it is possible to set a timeout time for
the module's MMC after which the system will be switched off unconditionally. For the setting
of the timeout refer to Chapter 3.4, OEM Module Quiescence Feedback.
9.2 Method 2: The Payload OS Does Not Support ACPI
Requirements:
• At system start on the payload side, the Kontron shutdown daemon “grnsd” must be start-
ed. It is included in the Linux board support packages for the AM4020. This daemon com-
municates cyclically with the MMC for the exchange of states, commands and
acknowledges. For this, it uses the OEM Module Quiescence Feedback command.
Refer to Chapter 3.4. In principle, it plays the same role as the ACPI daemon of Method
1 above.