[dpdk-dev] [PATCH v6 5/5] doc: add aarch32 build guidance

["Juraj Linkeš" <juraj.linkes@pantheon.tech>]

From: Phil Yang <phil.yang@arm.com>

Add cross-compiling guidance for 32-bit aarch32 DPDK on aarch64 host.

Signed-off-by: Phil Yang <phil.yang@arm.com>
---
 .../linux_gsg/cross_build_dpdk_for_arm64.rst  | 30 ++++++++++++++-----
 1 file changed, 23 insertions(+), 7 deletions(-)

diff --git a/doc/guides/linux_gsg/cross_build_dpdk_for_arm64.rst b/doc/guides/linux_gsg/cross_build_dpdk_for_arm64.rst
index c5875a6d5..07085e3ea 100644
--- a/doc/guides/linux_gsg/cross_build_dpdk_for_arm64.rst
+++ b/doc/guides/linux_gsg/cross_build_dpdk_for_arm64.rst
@@ -1,15 +1,16 @@
 ..  SPDX-License-Identifier: BSD-3-Clause
     Copyright(c) 2018 ARM Corporation.
 
-Cross compile DPDK for ARM64
-============================
-This chapter describes how to cross compile DPDK for ARM64 from x86 build hosts.
+Cross compile DPDK for aarch64 and aarch32
+==========================================
+This chapter describes how to cross compile DPDK for aarch64 from x86 build hosts and compile
+32-bit aarch32 DPDK from aarch64 build hosts.
 
 .. note::
 
-   Whilst it is recommended to natively build DPDK on ARM64 (just
-   like with x86), it is also possible to cross-build DPDK for ARM64. An
-   ARM64 cross compile GNU toolchain is used for this.
+   Whilst it is recommended to natively build DPDK on aarch64 (just
+   like with x86), it is also possible to cross-build DPDK for aarch64.
+   An aarch64 cross compile GNU toolchain is used for this.
 
 Obtain the cross tool chain
 ---------------------------
@@ -88,18 +89,33 @@ To install it in Ubuntu::
 
    sudo apt-get install pkg-config-aarch64-linux-gnu
 
+.. note::
+
+    Some aarch64 platforms support EL0 aarch32 mode, which means the 32-bit aarch32 applications
+    can run on aarch64. The armhf architecture toolchain ``gcc-arm-linux-gnueabihf`` is required
+    for aarch32 on aarch64. To install it in Ubuntu::
+
+       sudo dpkg --add-architecture armhf
+       sudo apt-get update
+       sudo apt-get install -y gcc gcc-arm-linux-gnueabihf libc6:armhf make binutils
+
 To cross-compile DPDK on a desired target machine we can use the following
 command::
 
 	meson cross-build --cross-file <target_machine_configuration>
 	ninja -C cross-build
 
-For example if the target machine is arm64 we can use the following
+For example if the target machine is aarch64 we can use the following
 command::
 
 	meson arm64-build --cross-file config/arm/arm64_armv8_linux_gcc
 	ninja -C arm64-build
 
+If the target machine is aarch32 we can use the following command::
+
+	meson arm32-build --cross-file config/arm/arm32_armv8a_linux_gcc
+	ninja -C arm32-build
+
 Configure and Cross Compile DPDK using Make
 -------------------------------------------
 To configure a build, choose one of the target configurations, like arm64-dpaa-linux-gcc and arm64-thunderx-linux-gcc.
-- 
2.20.1