[PATCH v3 5/5] config/arm: add AMD CDX

[Ruifeng Wang]

> -----Original Message-----
> From: Ferruh Yigit <ferruh.yigit at amd.com>
> Sent: Monday, May 8, 2023 7:27 PM
> To: Gupta, Nipun <Nipun.Gupta at amd.com>; dev at dpdk.org; thomas at monjalon.net;
> david.marchand at redhat.com; Honnappa Nagarahalli <Honnappa.Nagarahalli at arm.com>; Ruifeng
> Wang <Ruifeng.Wang at arm.com>
> Cc: Anand, Harpreet <harpreet.anand at amd.com>; Agarwal, Nikhil <nikhil.agarwal at amd.com>
> Subject: Re: [PATCH v3 5/5] config/arm: add AMD CDX
> 
> On 5/8/2023 11:24 AM, Gupta, Nipun wrote:
> >
> >
> >> -----Original Message-----
> >> From: Yigit, Ferruh <Ferruh.Yigit at amd.com>
> >> Sent: Thursday, May 4, 2023 8:59 PM
> >> To: Gupta, Nipun <Nipun.Gupta at amd.com>; dev at dpdk.org;
> >> thomas at monjalon.net; david.marchand at redhat.com
> >> Cc: Anand, Harpreet <harpreet.anand at amd.com>; Agarwal, Nikhil
> >> <nikhil.agarwal at amd.com>
> >> Subject: Re: [PATCH v3 5/5] config/arm: add AMD CDX
> >>
> >> On 4/21/2023 3:54 PM, Nipun Gupta wrote:
> >>> Adding support for AMD CDX devices
> >>>
> >>> Signed-off-by: Nipun Gupta <nipun.gupta at amd.com>
> >>> ---
> >>>  config/arm/arm64_cdx_linux_gcc | 17 +++++++++++++++++
> >>>  config/arm/meson.build         | 14 ++++++++++++++
> >>>  2 files changed, 31 insertions(+)
> >>>  create mode 100644 config/arm/arm64_cdx_linux_gcc
> >>>
> >>> diff --git a/config/arm/arm64_cdx_linux_gcc
> >> b/config/arm/arm64_cdx_linux_gcc
> >>> new file mode 100644
> >>> index 0000000000..8e6d619dae
> >>> --- /dev/null
> >>> +++ b/config/arm/arm64_cdx_linux_gcc
> >>> @@ -0,0 +1,17 @@
> >>> +[binaries]
> >>> +c = ['ccache', 'aarch64-linux-gnu-gcc'] cpp = ['ccache',
> >>> +'aarch64-linux-gnu-g++'] ar = 'aarch64-linux-gnu-ar'
> >>> +as = 'aarch64-linux-gnu-as'
> >>> +strip = 'aarch64-linux-gnu-strip'
> >>> +pkgconfig = 'aarch64-linux-gnu-pkg-config'
> >>> +pcap-config = ''
> >>> +
> >>> +[host_machine]
> >>> +system = 'linux'
> >>> +cpu_family = 'aarch64'
> >>> +cpu = 'armv8-a'
> >>> +endian = 'little'
> >>> +
> >>> +[properties]
> >>> +platform = 'cdx'
> >>> diff --git a/config/arm/meson.build b/config/arm/meson.build index
> >>> 5213434ca4..39b8929534 100644
> >>> --- a/config/arm/meson.build
> >>> +++ b/config/arm/meson.build
> >>> @@ -305,6 +305,18 @@ soc_bluefield = {
> >>>      'numa': false
> >>>  }
> >>>
> >>> +soc_cdx = {
> >>> +    'description': 'AMD CDX',
> >>> +    'implementer': '0x41',
> >>> +    'part_number': '0xd42',
> >>> +    'flags': [
> >>> +        ['RTE_MACHINE', '"cdx"'],
> >>> +        ['RTE_MAX_LCORE', 16],
> >>> +        ['RTE_MAX_NUMA_NODES', 1]
> >>> +    ],
> >>> +    'numa': false
> >>> +}
> >>
> >> Hi Nipun,
> >>
> >> Why we need a new arm platform/config? Is it because of above flags?
> >> If it can work with default values, I think we can drop this patch.
> >
> > Hi Ferruh,
> >
> > CDX driver works with generic ARM compilation too (arm64_armv8_linux_gcc).
> >
> > The versal platforms supporting CDX have A78 cores, and adding this
> > cdx config Helps to provide gcc option "march= armv8.4-a" which is for
> > implementer "0xd42" (ARM cortex A78 cores)., whereas for generic ARM
> > compilation "march= armv8-a".
> >
> > Maybe ARM guys can provide more information regarding if there is any
> > impact on using generic architecture flag (i.e. march= armv8a) on A78 cores.
> >
> 
> Hi Honnappa, Ruifeng,
> 
> Can you please support on this question, what is the difference of 'march= armv8-a' flag
> (comparing march= armv8a)?
> Should we consider adding an arm config file to support this flag?

I see there is a new version without change to config file.
FWIW, native build is fine without this change. Because the specific (implementer, part number) flags
are already in place. What enabled by this change are options for soc build (-Dplatform=cdx) and
cross-build (--cross-file arm64_cdx_linux_gcc).

Regards,
Ruifeng
> 
> Thanks,
> ferruh
>