Why flag ?

• If the code changes has to be enabled only on certain scenarios or only applicable for specific boards , then we have to define the flag .

Defining a new flag 

• The flag has to be defined in ccsp_common.inc file
• There are two ways to define the flag

                      1. Having the flag enabled always
                      2. Enabling only for specific board or on specific condition

Having the flag enabled always 

• Go to ccsp_common.inc file
• Add the flag under "CFLAGS_append +="  

• Syntax

  CFLAGS_append +=  " <FLAG> "

• Sample 

  CFLAGS_append +=  "  .........  -DRDKB_FEATURE "

• By this method, the flag is set to 1 always 
• Now add the flag at required pieces of code

Enabling only for specific board or on specific condition

• Go to ccsp_common.inc file
• Add the flag using DISTRO_FEATURE as below

• Syntax 

  CFLAGS_append += " ${@bb.utils.contains('DISTRO_FEATURES', '<keyword>', '<FLAG>', '', d)}"

• Sample

  CFLAGS_append += " ${@bb.utils.contains('DISTRO_FEATURES', 'rdkb', '-DRDKB_FEATURE', '', d)}"

• Now the flag has to be added in the platform specific .conf file 

• Syntax

  DISTRO_FEATURES_append = " ........ <keyword> "

• Sample

  File : In Rpi, raspberrypi-rdk-broadband.conf DISTRO_FEATURES_append = " ........ rdkb "

• With this method, the flag is set to 1 for the specific platform
• Now add the flag at required pieces of code