package/dpdk: make apps selectable

Add BR2_PACKAGE_DPDK_APPS_LIST to control which DPDK applications are
built:
  - empty : use DPDK defaults
  - none  : disable all apps (-Ddisable_apps='*')
  - list  : pass to -Denable_apps= (comma-separated)

Signed-off-by: Maxime Leroy <maxime@leroys.fr>
Signed-off-by: Julien Olivain <ju.o@free.fr>

package/dpdk/Config.in

@@ -85,6 +85,27 @@ config BR2_PACKAGE_DPDK_LIBS_LIST
 	  Buildroot packages for external dependencies. DPDK
 	  configuration will fail in case of missing dependencies.
 
+config BR2_PACKAGE_DPDK_APPS_LIST
+	string "List of enabled applications"
+	help
+	  Controls which DPDK applications are built.
+
+	  Values:
+	    (empty): use DPDK defaults
+	    none   : build no apps
+	    list   : e.g. "test-cmdline,test-pmd"
+
+	  To list all applications found in the DPDK source tree:
+	    find app -mindepth 2 -maxdepth 2 -type f -name meson.build \
+	      -printf '%h\n' | xargs -n1 basename | sort -u
+
+	  Note: providing manually a list of dpdk libraries to enable
+	  does not automatically enable its dependencies (internal or
+	  external). It is the user responsiblity to add internal dpdk
+	  dependencies in this list, and/or select the relevant
+	  Buildroot packages for external dependencies. DPDK
+	  configuration will fail in case of missing dependencies.
+
 endif
 
 comment "dpdk needs a glibc toolchain w/ threads, gcc >= 4.9, headers >= 4.19"

package/dpdk/dpdk.mk

@@ -65,6 +65,15 @@ ifneq ($(DPDK_LIBS),)
   endif
 endif
 
+DPDK_APPS := $(call qstrip,$(BR2_PACKAGE_DPDK_APPS_LIST))
+ifneq ($(DPDK_APPS),)
+  ifeq ($(DPDK_APPS),none)
+    DPDK_CONF_OPTS += -Ddisable_apps='*'
+  else
+    DPDK_CONF_OPTS += -Denable_apps='$(DPDK_APPS)'
+  endif
+endif
+
 ifeq ($(BR2_PACKAGE_DPDK_TESTS),y)
 DPDK_CONF_OPTS += -Dtests=true
 else