package/linux-tools: add USB tools (testusb and ffs-test)

Extend the linux-tools package to also build the userspace USB tools,
which currently include testusb and ffs-test.

These tools are in the kernel tree since a long time, and althogh a
Makefile had been present since kernel 2.6.39, it has been entirely
rewritten (with an install rule) back with kernel 5.9, to allow building
the same way as other tools provided with the kernel.

We make use of the Makefile install rule, thus version >= 5.9 is
required. Support for older kernels may be added later if needed, and
is left as an exercise for the motivated party.

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
[yann.morin.1998@free.fr: fix history of Makefile]
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

DEVELOPERS

@@ -1874,6 +1874,7 @@ F:	configs/zynqmp_zcu106_defconfig
 F:	package/agentpp/
 F:	package/exim/
 F:	package/libpjsip/
+F:	package/linux-tools/linux-tool-usbtools.mk.in
 F:	package/qpid-proton/
 F:	package/rtl8188eu/
 F:	package/snmppp/

package/linux-tools/Config.in

@@ -135,6 +135,32 @@ comment "selftests needs BR2_PACKAGE_BUSYBOX_SHOW_OTHERS and a toolchain w/ dyna
 	depends on !BR2_PACKAGE_BUSYBOX_SHOW_OTHERS || \
 		BR2_STATIC_LIBS || !BR2_TOOLCHAIN_HEADERS_AT_LEAST_3_14
 
+config BR2_PACKAGE_LINUX_TOOLS_USBTOOLS
+	bool "USB test programs"
+	select BR2_PACKAGE_LINUX_TOOLS
+	help
+	  Build and install the USB test tools.
+
+	  These tools exist since Linux 2.6.35, but Buildroot can build
+	  them only with kernel versions 5.9 and later.
+
+if BR2_PACKAGE_LINUX_TOOLS_USBTOOLS
+
+config BR2_PACKAGE_LINUX_TOOLS_USBTOOLS_TESTUSB
+	bool "testusb"
+	help
+	  testusb issues ioctls to perform the tests implemented by the
+	  kernel driver.  It can generate a variety of transfer
+	  patterns.
+
+	  See http://www.linux-usb.org/usbtest/
+
+config BR2_PACKAGE_LINUX_TOOLS_USBTOOLS_FFSTEST
+	bool "ffs-test"
+	help
+	  User mode filesystem api for usb composite function
+endif
+
 config BR2_PACKAGE_LINUX_TOOLS_TMON
 	bool "tmon"
 	depends on BR2_TOOLCHAIN_HAS_THREADS

package/linux-tools/linux-tool-usbtools.mk.in

@@ -0,0 +1,34 @@
+################################################################################
+#
+# usbtools
+#
+################################################################################
+
+LINUX_TOOLS += usbtools
+
+USBTOOLS_MAKE_OPTS = $(LINUX_MAKE_FLAGS) LDFLAGS="$(TARGET_LDFLAGS)"
+
+LINUX_TOOLS_USBTOOLS_LIST = \
+	$(if $(BR2_PACKAGE_LINUX_TOOLS_USBTOOLS_TESTUSB),testusb) \
+	$(if $(BR2_PACKAGE_LINUX_TOOLS_USBTOOLS_FFSTEST),ffs-test)
+
+define USBTOOLS_BUILD_CMDS
+	$(Q)if ! grep install $(LINUX_DIR)/tools/usb/Makefile >/dev/null 2>&1 ; then \
+		echo "Your kernel version is too old to build the USB tools." ; \
+		echo "At least kernel 5.9 must be used." ; \
+		exit 1 ; \
+	fi
+
+	$(TARGET_MAKE_ENV) $(MAKE) -C $(LINUX_DIR)/tools/usb \
+		ALL_TARGETS="$(LINUX_TOOLS_USBTOOLS_LIST)" \
+		$(USBTOOLS_MAKE_OPTS) \
+		all
+endef
+
+define USBTOOLS_INSTALL_TARGET_CMDS
+	$(TARGET_MAKE_ENV) $(MAKE) -C $(LINUX_DIR)/tools/usb \
+		ALL_TARGETS="$(LINUX_TOOLS_USBTOOLS_LIST)" \
+		$(USBTOOLS_MAKE_OPTS) \
+		DESTDIR=$(TARGET_DIR) \
+		install
+endef