Re: [dpdk-dev] Clarification for eth_driver changes

[Shreyansh Jain <shreyansh.jain@nxp.com>]

Hello David,

On Thursday 10 November 2016 01:46 PM, David Marchand wrote:
> Hello Shreyansh,
>
> On Thu, Nov 10, 2016 at 8:26 AM, Shreyansh Jain <shreyansh.jain@nxp.com> wrote:
>> I need some help and clarification regarding some changes I am doing to
>> cleanup the EAL code.
>>
>> There are some changes which should be done for eth_driver/rte_eth_device
>> structures:
>>
>> 1. most obvious, eth_driver should be renamed to rte_eth_driver.
>> 2. eth_driver currently has rte_pci_driver embedded in it
>>  - there can be ethernet devices which are _not_ PCI
>>  - in which case, this structure should be removed.
>
> Do we really need to keep a eth_driver ?

No. As you have rightly mentioned below (as well as in your Jan'16 
post), it is a mere convenience.

> As far as I can see, it is only a convenient wrapper for existing pci
> drivers, but in the end it is just a pci_driver with ethdev context in
> it that could be pushed to each existing driver.

Indeed. My problem (or lack of understanding) is that all PMDs rely on 
it and I don't know in what all pattern they have envisioned using this 
model of ethdev->pci_dev, the initialization sequences.
rte_device->init/uninit would settle most of those worries, I think.

>
> In my initial description
> http://dpdk.org/ml/archives/dev/2016-January/031390.html, what I had
> in mind was only having a rte_eth_device pointing to a generic
> rte_device.

Though I had read it (during the rte_device/driver series) but didn't 
remember it while posting this. I agree with your point of doing away 
with eth_driver.

> If we need to invoke some generic driver ops from ethdev (I can only
> see the ethdev hotplug api, maybe I missed something), then we would
> go through rte_eth_device -> rte_device -> rte_driver.

Agree with you.

> The rte_driver keeps its own bus/private logic in its code, and no
> need to expose a type.

Agree.

>
>
>> 3. Similarly, rte_eth_dev has rte_pci_device which should be replaced with
>> rte_device.
>
> Yes, that's the main change for me.

Indeed. This is a big change. It impacts a lot of EAL code.

>
>
> Thanks.
>

Intent of this email was to know if I am missing something in assuming 
that eth_driver is actually not being used much. I will keep the 
comments from your email in mind while making changes. Thanks.

_
Shreyansh