Artesyn ATCA-8310 Installation and Use (May 2014) - Manual (Page 170)

U-Boot
ATCA-8310 Installation and Use (6806800M72E) 170
autoload undefined If set to "no", DHCP will only configure the network
netretry undefined Either "yes" (default), "no" or "once". Defines the behaviour of failing
network commands.
pram 0 This is a decimal value encoding a memory size in kilobytes (1024
bytes). The specified amount of memory is reserved at the end of
physical memory and will not ne overwritten by u-boot. This
memory will also be retained over reset (except when the
"pmem_disable" variable is set).
The size of usable memory is reported in the variable "v_
bootm_size". If Linux shall be made aware of this memory limit,
assign the "bootm_size" variable to the value of "v_bootm_size"
before starting Linux.
The second variable encoding the memory size resulting from the
"pram" variable is "mem". This a decimal value in kilobyte (with a "k"
suffix).
clear_mem_top undefined If set this variable defines an address up to which memory contents
are set to zero at reset. Memory above this limit remains untouched.
The variable's value can either be a hexadecimal value (aligned to
16MB), or the string "pram".
In the latter case the limit is set according to the "pram" variable (see
above). If the "pram" variable is not defined, no memory is cleared.
pmem_disable undefined If set the persistent memory feature is disabled. This means that the
DDR3 memory will not be put into self-refresh mode at reset.
This makes the variables "pram" and "clear_mem_top" obsolete,
since the complete memory will be re-initialized at reset (to initialize
the ECC data).
hwconf undefined Can be used to configure DRAM interleaving options. See 2.1.11.
Table 6-3 Variables for Controlling the Boot Progress (continued)
Variable Name Default Description