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

[Ferruh Yigit]

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?

Thanks,
ferruh