[dpdk-dev] Clarification for eth_driver changes

[Thomas Monjalon]

2016-11-10 14:12, Shreyansh Jain:
> On Thursday 10 November 2016 01:33 PM, Thomas Monjalon wrote:
> > 2016-11-10 15:51, Jianbo Liu:
> >> On 10 November 2016 at 15:26, Shreyansh Jain <shreyansh.jain at nxp.com> wrote:
> >>> This is what the current outline of eth_driver is:
> >>>
> >>> +------------------------+
> >>> | eth_driver             |
> >>> | +---------------------+|
> >>> | | rte_pci_driver      ||
> >>> | | +------------------+||
> >>> | | | rte_driver       |||
> >>> | | |  name[]          |||
> >>> | | |  ...             |||
> >>> | | +------------------+||
> >>> | |  .probe             ||
> >>> | |  .remove            ||
> >>> | |  ...                ||
> >>> | +---------------------+|
> >>> |  .eth_dev_init         |
> >>> |  .eth_dev_uninit       |
> >>> +------------------------+
> >>>
> >>> This is what I was thinking:
> >>>
> >>> +---------------------+        +----------------------+
> >>> | rte_pci_driver      |        |eth_driver            |
> >>> | +------------------+|       _|_struct rte_driver *p |
> >>> | | rte_driver       <-------/ | .eth_dev_init        |
> >>> | |  ...             ||        | .eth_dev_uninit      |
> >>> | |  name            ||        +----------------------+
> >>> | |  <more>          ||
> >>> | +------------------+|
> >>> |  <PCI specific info>|
> >>> +---------------------+
> >>>
> >>> ::Impact::
> >>> Various drivers use the rte_pci_driver embedded in the eth_driver object for
> >>> device initialization.
> >>>  == They assume that rte_pci_driver is directly embedded and hence simply
> >>> dereference.
> >>>  == e.g. eth_igb_dev_init() in drivers/net/e1000/igb_ethdev.c file
> >>>
> >>> With the above change, such drivers would have to access rte_driver and then
> >>> perform container_of to obtain their respective rte_xxx_driver.
> >>>  == this would be useful in case there is a non-PCI driver
> >>>
> >>> ::Problem::
> >>> I am not sure of reason as to why eth_driver embedded rte_pci_driver in
> >>> first place - other than a convenient way to define it before PCI driver
> >>> registration.
> >>>
> >>> As all the existing PMDs are impacted - am I missing something here in
> >>> making the above change?
> >>>
> >>
> >> How do you know eth_driver->p is pointing to a rte_pci_driver or rte_soc_driver?
> >> Maybe you need to add a type/flag in rte_driver.
> >
> > Why do you need any bus information at ethdev level?
> 
> AFAIK, we don't need it. Above text is not stating anything on that 
> grounds either, I think. Isn't it?

No, I was replying to Jianbo.
Anyway, David made a more interesting comment.