Hello Stephen,
On 06/16/2014 09:52 PM, Stephen Warren wrote:
On 06/12/2014 03:46 AM, Przemyslaw Marczak wrote:
This patch introduces new feature: initialization of the dfu bootloader entity from a separate environmental variable which can be set on a boot time.
By default, DFU always check environmental variable: $dfu_alt_info.
Changes:
- DFU will also look for environmental variable: $dfu_alt_bootloader
- if any of dfu_alt_* variable is properly defined, then function dfu_init_env_entities() will return success.
Use case: Some devices can boot from various media type (SD, eMMC, NAND, etc.) or some board configs are common for more than one board type. In a such case, bootloader is probably placed on a different devices or even offsets. So such DFU feature is welcome.
Why should the "dfu" command look at different environment variables? Whatever code dynamically sets the value of $dfu_alt_bootloader should simply set $dfu_alt_info instead.
Dynamically setting of any entity cold be done at boot time, like this:
# int buf_len = strlen(alt_bootloader) + strlen(CONFIG_DFU_ALT) + 4; # char *buf = memalign(1, buf_len); # # sprintf(buf, "%s; %s", alt_bootloader, CONFIG_DFU_ALT); # setenv("dfu_alt_info", buf);
But overwriting the $dfu_alt_info on each boot is not a good idea. If user modify the dfu entities - then it will be overwritten at next boot.
In the other side I can store entities as $dfu_alt_default and change the above code to:
# char *alt_default = getenv("dfu_alt_default"); # if (!alt_default) # alt_default = ""; # # int buf_len = strlen(alt_bootloader) + strlen(alt_default) + 4; # char *buf = memalign(1, buf_len); # # sprintf(buf, "%s; %s", alt_bootloader, alt_default); # setenv("dfu_alt_info", buf);
But then, there is some mess in the environment because of duplicated default alt_info.
Those both, above solutions takes more time than just one simple line:
# setenv("dfu_alt_bootlaoder", CONFIG_SOME_ALT_INFO);
like in this patch set.
Maybe better could be modification of the function dfu_init_env_entities() to support parsing variables in the $dfu_alt_info instead of hard coded env variables names, e.g:
dfu_alt_info="${alt_info_boot}, ${alt_info_system},..."
dfu_alt_info could be set with default variables names in each board config file in the CONFIG_EXTRA_ENV_SETTINGS and then just one proper variable could be set at boot, and others from env - simple and fast.
And then in the dfu init code - entities are initialized from env variables - if they exists, like in the loop code from this patch.
I need some solution to automatically set proper bootloader entities, since one binary can be stored on SD and eMMC cards.
Thank you,