From 088cba271e3e9e87425d0a060a493af193a571d9 Mon Sep 17 00:00:00 2001
From: Joerg Hofrichter <joerg.hofrichter@ni.com>
Date: Fri, 20 Sep 2024 21:45:50 +0200
Subject: [PATCH] dpdk: find DPDK using pkg-config

The parameters for compiling and linking against DPDK (DPDK_CFLAGS
and DPDK_LDFLAGS or DPDK_INCLUDE_DIRS, DPDK_LIBRARIES and
DPDK_LIBRARY_DIRS) are not trivial to determine and can be best
provided by pkg-config. Therefore, use pkg-config to find DPDK and
do not allow user provided DPDK variables.

To compile UHD against DPDK which was installed to a custom prefix,
e.g. /opt/dpdk-22.11, provide this path as parameter
CMAKE_PREFIX_PATH:

    cmake .. -DCMAKE_PREFIX_PATH=/opt/dpdk-22.11
---
 host/cmake/Modules/FindDPDK.cmake | 88 ++++---------------------------
 host/lib/CMakeLists.txt           |  6 ++-
 2 files changed, 16 insertions(+), 78 deletions(-)

diff --git a/host/cmake/Modules/FindDPDK.cmake b/host/cmake/Modules/FindDPDK.cmake
index 75d9a0c1d..94779ae60 100644
--- a/host/cmake/Modules/FindDPDK.cmake
+++ b/host/cmake/Modules/FindDPDK.cmake
@@ -4,86 +4,20 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 #
-# - Find DPDK
-# Find the DPDK includes and client library
-# This module defines
-#  DPDK_INCLUDE_DIRS, where to find rte_config.h and rte_version.h
-#  DPDK_LIBRARIES, the libraries needed by a DPDK user
+# Find DPDK by using pkg-config. This sets various variables prefixed
+# with "DPDK_".
+#
+# The following variables are used by the UHD build system:
+#  DPDK_INCLUDE_DIRS, the include directories
+#  DPDK_CFLAGS, the compiler flags
+#  DPDK_LDFLAGS, the linker flags
+#  DPDK_LIBRARIES, the list of libraries
 #  DPDK_FOUND, If false, do not try to use DPDK.
-# also defined, but not for general use are
-#  DPDK_LIBRARY, where to find the DPDK library.
 
 include(FindPackageHandleStandardArgs)
 
-function(DPDK_READ_VERSION DPDK_VERSION DPDK_INCLUDE_DIRS)
-    if(NOT DPDK_INCLUDE_DIRS)
-        return()
-    endif()
-
-    file(READ "${DPDK_INCLUDE_DIRS}/rte_version.h"
-        DPDK_VERSION_STR
-    )
-    string(REGEX MATCH "#define RTE_VER_YEAR ([0-9]+)" _ ${DPDK_VERSION_STR})
-    set(DPDK_VERSION_MAJOR ${CMAKE_MATCH_1})
-
-    string(REGEX MATCH "#define RTE_VER_MONTH ([0-9]+)" _ ${DPDK_VERSION_STR})
-    set(DPDK_VERSION_MINOR ${CMAKE_MATCH_1})
-
-    set(DPDK_VERSION "${DPDK_VERSION_MAJOR}.${DPDK_VERSION_MINOR}" PARENT_SCOPE)
-endfunction()
-
-if(DPDK_LIBRARIES AND DPDK_INCLUDE_DIRS)
-    set(DPDK_USER_PROVIDED ON)
-else()
-    set(DPDK_USER_PROVIDED OFF)
-endif()
-
 find_package(PkgConfig)
-PKG_CHECK_MODULES(PC_DPDK QUIET libdpdk>=18.11)
+PKG_CHECK_MODULES(DPDK libdpdk>=18.11)
 
-find_path (DPDK_VERSION_INCLUDE_DIR rte_version.h
-    HINTS ${PC_DPDK_INCLUDE_DIRS}
-    PATHS ENV RTE_INCLUDE
-    PATH_SUFFIXES dpdk
-)
-find_path (DPDK_CONFIG_INCLUDE_DIR rte_config.h
-    HINTS ${PC_DPDK_INCLUDE_DIRS}
-    PATHS ENV RTE_INCLUDE
-    PATH_SUFFIXES dpdk
-)
-
-# Check for linker script that pulls in the APIs
-find_library(DPDK_LIBRARY
-    dpdk
-    HINTS ${PC_DPDK_LIBDIR}
-    PATHS $ENV{RTE_SDK_DIR}/$ENV{RTE_TARGET}/lib
-)
-
-if(NOT DPDK_USER_PROVIDED)
-    set(DPDK_INCLUDE_DIRS ${PC_DPDK_INCLUDE_DIRS})
-    list(APPEND DPDK_INCLUDE_DIRS ${DPDK_VERSION_INCLUDE_DIR})
-    list(APPEND DPDK_INCLUDE_DIRS ${DPDK_CONFIG_INCLUDE_DIR})
-    list(REMOVE_DUPLICATES DPDK_INCLUDE_DIRS)
-endif()
-
-if(DPDK_USER_PROVIDED)
-    DPDK_READ_VERSION(DPDK_VERSION ${DPDK_INCLUDE_DIRS})
-else()
-    set(DPDK_LIBRARIES ${PC_DPDK_LINK_LIBRARIES})
-
-    if(DPDK_LIBRARY)
-        list(APPEND DPDK_LIBRARIES ${DPDK_LIBRARY})
-        list(REMOVE_DUPLICATES DPDK_LIBRARIES)
-    endif()
-
-    if(PC_DPDK_FOUND)
-        set(DPDK_VERSION ${PC_DPDK_VERSION})
-    else()
-        DPDK_READ_VERSION(DPDK_VERSION ${DPDK_INCLUDE_DIRS})
-    endif(PC_DPDK_FOUND)
-endif()
-
-find_package_handle_standard_args(DPDK
-    REQUIRED_VARS DPDK_INCLUDE_DIRS DPDK_LIBRARIES
-    VERSION_VAR DPDK_VERSION
-)
+find_package_handle_standard_args(DPDK DEFAULT_MSG DPDK_INCLUDE_DIRS DPDK_CFLAGS DPDK_LDFLAGS DPDK_LIBRARIES)
+mark_as_advanced(DPDK_INCLUDE_DIRS DPDK_CFLAGS DPDK_LDFLAGS DPDK_LIBRARIES)
diff --git a/host/lib/CMakeLists.txt b/host/lib/CMakeLists.txt
index 62e052d64..412197c81 100644
--- a/host/lib/CMakeLists.txt
+++ b/host/lib/CMakeLists.txt
@@ -60,7 +60,7 @@ endmacro(INCLUDE_SUBDIRECTORY)
 message(STATUS "")
 # Dependencies
 find_package(LIBUSB)
-find_package(DPDK 18.11...21.11)
+find_package(DPDK)
 LIBUHD_REGISTER_COMPONENT("USB" ENABLE_USB ON "ENABLE_LIBUHD;LIBUSB_FOUND" OFF OFF)
 # Devices
 LIBUHD_REGISTER_COMPONENT("B100" ENABLE_B100 ON "ENABLE_LIBUHD;ENABLE_USB" OFF OFF)
@@ -182,6 +182,10 @@ if(ENABLE_MPMD)
 endif()
 add_library(uhd SHARED ${libuhd_sources})
 target_link_libraries(uhd ${Boost_LIBRARIES} ${libuhd_libs})
+if(DPDK_FOUND)
+    target_compile_options(uhd PRIVATE ${DPDK_CFLAGS})
+    target_link_options(uhd PUBLIC ${DPDK_LDFLAGS})
+endif()
 if(APPLE)
     target_link_options(uhd PRIVATE "LINKER:-undefined,dynamic_lookup")
     target_link_options(uhd PRIVATE "-flat_namespace")