NAME

       memtool - display and modify memory

SYNOPSIS

       memtool -V
       memtool md [-b|-w|-l|-q] [-x] [-s filename] region
       memtool mw [-b|-w|-l|-q] [-d filename] start data...

DESCRIPTION

       memtool  allows one to read and write regions of files. When applied to /dev/mem (which is
       the default file) the regions represent memory mapped registers.

       There are currently two subcommands: mw to write to memory/a file; and  md  to  read  from
       memory/a file.

       Usually  memtool  operates  on files (regular or devices) using mmap(2). If filename is of
       the form mdio:ethname.id with ethname being the name of an ethernet device and id being an
       MDIO  address,  the  phy  with  address  id on the MDIO bus related to the ethernet device
       ethname is accessed instead. To prevent ambiguities when using the mmap access method, use
       mmap:filename as parameter.

       Note  that  on  some  machines there are alignment restrictions that forbid for example to
       read a word from an address that is not word aligned. memtool doesn't try to be smart here
       but simply tries what is requested by the caller.  This might result in all kind of errors
       which are not considered to be a bug of the tool, but either the machine or the caller.

OPTIONS

       -V     Dump memtool version and exit

COMMON OPTIONS FOR SUBCOMMANDS

       -b     Use byte wise (8-bit) access

       -w     Use word wise (16-bit) access

       -l     Use long wise (32-bit) access

       -q     Use quad wise (64-bit) access

       -d filename
              Write to filename.

       -s filename
              Read from filename.

       -x     Swap bytes at output

REGIONS

       Memory regions can be specified in two different forms:

       start[+size]

       start-end

       start specifies the byte offset  of  the  region's  beginning,  i.e.  the  first  included
       address.   size  specifies  the  size  of  the  region  in  bytes  and  defaults to 0x100.
       Alternatively end specifies the offset of the  last  included  address.   Offsets  can  be
       specified  in  decimal or hexadecimal with a prefix 0x.  Additionally you can use suffixes
       G, M, and k, which multiply by 1024^3, 1024^2, and 1024 respectively.