[AMD Official Use Only - General]
> -----Original Message-----
> From: Yigit, Ferruh <ferruh.yi...@amd.com>
> Sent: Monday, May 8, 2023 11:17 PM
> To: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>; Gupta, Nipun
> <nipun.gu...@amd.com>; dev@dpdk.org; tho...@monjalon.net;
> david.march...@redhat.com; Ruifeng Wang <ruifeng.w...@arm.com>
> Cc: Anand, Harpreet <harpreet.an...@amd.com>; Agarwal, Nikhil
> <nikhil.agar...@amd.com>; nd <n...@arm.com>
> Subject: Re: [PATCH v3 5/5] config/arm: add AMD CDX
>
> On 5/8/2023 6:16 PM, Honnappa Nagarahalli wrote:
> > <snip>
> >
> >>>>
> >>>> On 4/21/2023 3:54 PM, Nipun Gupta wrote:
> >>>>> Adding support for AMD CDX devices
> >>>>>
> >>>>> Signed-off-by: Nipun Gupta <nipun.gu...@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)?
> > I am assuming you meant, 'march=armv8.4-a' vs 'march=armv8-a'.
> >
>
> Yes
>
> > 'march=armv8-a' will compile for the ARM V8.0-a ISA which is the base V8-a
> version of the ISA. This compilation ensures that the binaries can run on any
> ARM V8-a platforms.
> > 'march=armv8.4-a' will compile the binary for ARM V8.4 ISA. The binary will
> use additional (possibly instructions that improve performance) instructions
> which are not supported in ARM V8.0-a. This binary can run only on machines
> that support V8.4-a and higher. But, it will provide optimized binary for the
> target platform.
> >
> >> Should we consider adding an arm config file to support this flag?
> > We support the optimized binary through the config files. We should keep
> these config changes.
> >
>
> Got it, thanks for the guidance.
Thanks Honnappa, Ferruh,
As discussed with Thomas too, we will add this as a separate platform patch,
with more platform details separated from CDX bus (patch sent out v4).
