Re: [RFC v2, net-next, PATCH 4/4] net/cpsw_switchdev: add switchdev mode of operation on cpsw driver

[Jiri Pirko <jiri@resnulli.us>]

Tue, Jun 19, 2018 at 01:19:00AM CEST, grygorii.strashko@ti.com wrote:
>
>
>On 06/14/2018 06:43 AM, Ilias Apalodimas wrote:
>> On Thu, Jun 14, 2018 at 01:39:58PM +0200, Jiri Pirko wrote:
>>> Thu, Jun 14, 2018 at 01:34:04PM CEST, ilias.apalodimas@linaro.org wrote:
>>>> On Thu, Jun 14, 2018 at 01:30:28PM +0200, Jiri Pirko wrote:
>>>>> Thu, Jun 14, 2018 at 01:11:30PM CEST, ilias.apalodimas@linaro.org wrote:
>>>>>
>>>>> [...]
>>>>>
>>>>>> @@ -2711,6 +2789,10 @@ static int cpsw_probe_dt(struct cpsw_platform_data *data,
>>>>>> 	if (of_property_read_bool(node, "dual_emac"))
>>>>>> 		data->switch_mode = CPSW_DUAL_EMAC;
>>>>>>
>>>>>> +	/* switchdev overrides DTS */
>>>>>> +	if (IS_ENABLED(CONFIG_TI_CPSW_SWITCHDEV))
>>>>>> +		data->switch_mode = CPSW_SWITCHDEV;
>>>>>
>>>>> So you force CPSW_SWITCHDEV mode if the CONFIG_TI_CPSW_SWITCHDEV is
>>>>> enabled. That does not sound right. I think that user should tell what
>>>>> mode does he want regardless what the kernel config is.
>>>> We discussed this during the V1 of the RFC. Yes it doesn't seem good, but the
>>>> device currently configures the modes using DTS (which is not correct). I choose
>>>> the .config due to that. I can't think of anything better, but i am open to
>>>> suggestions
>>>
>>> Agreed that DTS does fit as well. I think that this might be a job for
>>> devlink parameters (patchset is going to be sent upstream next week).
>>> You do have 1 bus address for the whole device (both ports), right?
>>>
>> Yes devlink sounds reasonable. I thyink there's only one bus for it, but then
>> again i am far from an expert on the hardware interrnals. Grygorii can correct
>> me if i am wrong.
>
>Devlink and NFS boot are not compatible as per my understanding, so .. 

? Why do you say so?


>
>Again, current driver, as is, supports NFS boot in all modes
>(how good is the cur driver is question which out of scope of this discussion).
>
>And we discussed this in RFC v1 - driver mode selection will be changed 
>if we will proceed and it will be new driver for proper switch support.
>
>Not sure about about Devlink (need to study it and we never got any requests from end
>users for this as I know), and I'd like to note (again) that this is embedded 
>(industrial/automotive etc), so everything preferred to be simple, fast and
>preferably configured statically (in most of the cases end users what boot time 
>configuration).

You need to study it indeed.

> 
>-- 
>regards,
>-grygorii