[v10,5/5] doc: add aarch32 build guidance

  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  | 34 +++++++++++++------
 1 file changed, 24 insertions(+), 10 deletions(-)
  

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Juraj Linke?
> Sent: Wednesday, September 16, 2020 4:21 PM
> To: thomas@monjalon.net; bruce.richardson@intel.com;
> aconole@redhat.com; maicolgabriel@hotmail.com
> Cc: juraj.linkes@pantheon.tech; dev@dpdk.org; Phil Yang
> <Phil.Yang@arm.com>
> Subject: [dpdk-dev] [PATCH v10 5/5] doc: add aarch32 build guidance
> 
> 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  | 34 +++++++++++++------
>  1 file changed, 24 insertions(+), 10 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 8a1d0e88b..1f2ff751d 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
>  ---------------------------
> @@ -88,14 +89,27 @@ To install it in Ubuntu::
> 
>     sudo apt-get install pkg-config-aarch64-linux-gnu
> 
> -To cross-compile DPDK on a desired target machine we can use the
> following
> -command::
> +.. 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-arm-linux-gnueabihf libc6:armhf
> + binutils
> +
> +To cross-compile DPDK on a desired target machine 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
> -command::
> +For example if the target machine is aarch64 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 use the following command::
> +
> +	meson arm32-build --cross-file config/arm/arm32_armv8a_linux_gcc
> +	ninja -C arm32-build
> --
> 2.20.1

Acked-by: Ruifeng Wang <ruifeng.wang@arm.com>