Re: [PATCH net-next v7 4/5] net: rnpgbe: Add basic mbx_fw support

[Yibo Dong]

On Wed, Aug 27, 2025 at 09:54:58PM +0200, Andrew Lunn wrote:
> > I try to explain the it:
> > 
> > driver-->fw, we has two types request:
> > 1. without response, such as mucse_mbx_ifinsmod
> > 2. with response, such as mucse_fw_get_macaddr
> > 
> > fw --> driver, we has one types request:
> > 1. link status (link speed, duplex, pause status...)
> 
> Is the firmware multi threaded? By that, i mean can there be two
> request/responses going on at once?
> 
> I'm assuming not.

No, fw is single threaded.

> 
> So there appears to be four use cases:
> 
> 1) Fire and forget, request without response.
> 2) Request with a response
> 3) Link state change from the firmware
> 4) Race condition: Request/response and link state change at the same time.
> 
> Again, assuming the firmware is single threaded, there must be a big
> mutex around the message box so there can only be one thread doing any
> sort of interaction with the firmware.
> 
> Since there can only be one thread waiting for the response, the
> struct completion can be a member of the message box. The thread
> waiting for a response uses wait_for_completion(mbx->completion).
> 
> The interrupt handler can look at the type of message it got from the
> firmware. If it is a link state, process it, and exit. If it is
> anything else, complete(mbx->completion) and exit.
> 
> I don't see the need for any sort of cookie.

Got it, I will try in patch which adds irq handler in the future.

> 
>   Andrew
> 

Thanks for your feedback.