Owner's manual
Software Description
85 AT8404 User Guide
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4.4 Firmware Administration
On a running AT8404 system, the switching application is executed from within the WindRiver Linux operat-
ing system environment. This includes the linux kernel itself which is started by the systems bootmonitor,
the root file system and the FASTPATH switching application itself. These software components, together
with the IPMC image, make the AT8404 firmware.
The flash holding the AT8404 software is divided into nine partitions. Partition mtd8 which holds the basic
boot initialization code is hardware write protected by default thus preventing it from being accidentially
overwritten by any update procedure. Partitions mtd3 and mtd7 hold a combined image containing boot-
monitor, kernel and root file system including the switching application. Four partitions are reserved for a
pair of redundant bootloader environment for each image. The partition scheme of the flash is shown below.
Note (1)The board does support OS images up to 24,75 MB size.
Note (2)Note that only the flash partitions mtd2 and mtd6 are using the JFFS2 file system for storage. All
other flash partitions are not formatted and accessible from Linux only as raw devices.
Note (3)The U-Boot boot loader uses one flash sector for storing its environment variables. These can be
saved and manipulated from the U-Boot CLI and using Linux tools. To enable atomic updates of the environ-
ment variables, U-Boot uses redundant environment sectors; in case of a failure in completely writing the
current sector (e.g. due to loss of power or reset during writes), it will automatically use the redundant envi-
ronment. Therefore each boot monitor uses two flash sectors (partitions) for storing its environment and
redundant copy.
Note (4)The boot monitor is different for firmware image 0 and firmware image 1. This is because early parts
of the boot monitor have to be relocated at build time for the address they execute from. Therefore both
firmware images (SW0 and SW1) contain boot monitor images able to execute on any of the possible
addresses. This allows for doing a verbatim copy of SW0 to SW1 and vice versa.
Table 4-23: FLASH Partition Scheme (128MB)
Partition Size [MB]
Start
Address
End
Address
Partition name
mtd8 0.25 FFFC0000 FFFFFFFF
Boot initialization code (U_Boot, write protected by
hardware setting
mtd7 0.25 FFF80000 FFFBFFFF SW0 - boot monitor image (U-Boot) Note (4)
0.25 FFF40000 FFF7FFFF
SW0 - Copy of boot monitor image for SW1 (U-Boot)
Note (4)
24.75 FE680000 FFF3FFFF SW0 - OS Image Note (1)
mtd6 38.00 FC080000 FE67FFFF SW0 - Non-volatile storage area (JFFS2) Note (2)
mtd5 0.25 FC040000 FC07FFFF SW0 - Redundant U-Boot environment A Note (3)
mtd4 0.25 FC000000 FC03FFFF SW0 - Redundant U-Boot environment B Note (3)
0.25 FBFC0000 FBF80000 Unused
mtd3 0.25 FBF80000 FBFBFFFF SW0 - boot monitor image (U-Boot) Note (4)
0.25 FBF40000 FBF7FFFF
SW1 - Copy of boot monitor image for SW0 (U-Boot)
Note (4)
24.75 FA680000 FBF3FFFF SW1 - OS Image Note (1)
mtd2 38.00 F8080000 FA67FFFF SW1 - Non-volatile storage area (JFFS2) Note (2)
mtd1 0.25 F8040000 F807FFFF SW1 - Redundant U-Boot environment A Note (3)
mtd0 0.25 F8000000 F803FFFF SW1 - Redundant U-Boot environment B Note (3)