Artesyn ATCA-9405 Installation and Use (May 2014) - Manual (Page 118)

Intelligent Peripheral Management Controller
ATCA-9405 Installation and Use (6806800M71G) 118
8.4.2 Payload Firmware Upgrade
The HPM.1 component u-boot is implemented with two SPI flashes, one active and one
backup. The IPMC always writes to the backup flash. Automatic rollback is implemented via
fail-safe architecture. For details about failsafe, see
Fail Safe Logic and Watchdog Support on
page 144 .
The IPMC always upgrades the backup boot flash as intended. However, the HPM1 command
Activate Firmware
does not reboot the payload firmware unconditionally. Instead the
blade can be rebooted gracefully to activate the firmware.
Executing two u-boot firmware upgrades without a payload reset does not upgrade both
flashes for security reason (just the backup flash can be programmed).
Crisis recovery is fully supported. Two broken u-boot images can be reprogrammed via IPMI
with the help of the ShMM.
8.4.3 IPMC Firmware Upgrade
The HPM1 component IPMI firmware stores its active and backup image within one physical
flash. A small bootloader is used to either jump to the active or to the backup image depending
on the boot flags indicating successful boot. The bootloader is implemented as HPM1
component; however there is no backup image.
The boot loader maintains redundant copies of the firmware in flash. Each time the IPMI
firmware is upgraded, a redundant copy of the current IPMI firmware is made in flash. Once the
new IPMI firmware is programmed, the IPMI controller resets itself to boot from the new
image. The boot loader also validates new IPMI firmware images. If the power up of the IPMI
controller is successful, then the actual image is made active and the previously active image
is made backup. If the power up fails, the boot loader automatically recovers from crisis by
switching to the first firmware image that has booted before.
The IPMI controller can be upgraded via KCS or IPMB interface. To ensure that the payload is not
interrupted during IPMI firmware upgrade, the IPMI controller stores all operational
information, such as e-keying, hot-swap state, last events to be queued, graceful shutdown
timeout, latest pin settings, and so on in non-volatile storage.