61 lines
2.1 KiB
Plaintext
61 lines
2.1 KiB
Plaintext
|
|
This is a demo implementation of a Linux command line tool to access
|
|
the U-Boot's environment variables.
|
|
|
|
In order to cross-compile fw_printenv, run
|
|
make CROSS_COMPILE=<your cross-compiler prefix> env
|
|
in the root directory of the U-Boot distribution. For example,
|
|
make CROSS_COMPILE=arm-linux- env
|
|
|
|
For the run-time utility configuration uncomment the line
|
|
#define CONFIG_FILE "/etc/fw_env.config"
|
|
in fw_env.h.
|
|
|
|
For building against older versions of the MTD headers (meaning before
|
|
v2.6.8-rc1) it is required to pass the argument "MTD_VERSION=old" to
|
|
make.
|
|
|
|
See comments in the fw_env.config file for definitions for the
|
|
particular board.
|
|
|
|
Configuration can also be done via #defines in the fw_env.h file. The
|
|
following lines are relevant:
|
|
|
|
#define HAVE_REDUND /* For systems with 2 env sectors */
|
|
#define DEVICE1_NAME "/dev/mtd1"
|
|
#define DEVICE2_NAME "/dev/mtd2"
|
|
#define DEVICE1_OFFSET 0x0000
|
|
#define ENV1_SIZE 0x4000
|
|
#define DEVICE1_ESIZE 0x4000
|
|
#define DEVICE1_ENVSECTORS 2
|
|
#define DEVICE2_OFFSET 0x0000
|
|
#define ENV2_SIZE 0x4000
|
|
#define DEVICE2_ESIZE 0x4000
|
|
#define DEVICE2_ENVSECTORS 2
|
|
|
|
Un-define HAVE_REDUND, if you want to use the utilities on a system
|
|
that does not have support for redundant environment enabled.
|
|
If HAVE_REDUND is undefined, DEVICE2_NAME is ignored,
|
|
as is ENV2_SIZE and DEVICE2_ESIZE.
|
|
|
|
The DEVICEx_NAME constants define which MTD character devices are to
|
|
be used to access the environment.
|
|
|
|
The DEVICEx_OFFSET constants define the environment offset within the
|
|
MTD character device.
|
|
|
|
ENVx_SIZE defines the size in bytes taken by the environment, which
|
|
may be less then flash sector size, if the environment takes less
|
|
then 1 sector.
|
|
|
|
DEVICEx_ESIZE defines the size of the first sector in the flash
|
|
partition where the environment resides.
|
|
|
|
DEVICEx_ENVSECTORS defines the number of sectors that may be used for
|
|
this environment instance. On NAND this is used to limit the range
|
|
within which bad blocks are skipped, on NOR it is not used.
|
|
|
|
To prevent losing changes to the environment and to prevent confusing the MTD
|
|
drivers, a lock file at /var/lock/fw_printenv.lock is used to serialize access
|
|
to the environment.
|