Recommended NAPI practices for new drivers

Recommended NAPI practices for new drivers

[Damien Dusha]

Dear All,

I am currently writing a driver for the IFI CAN IP Core [1]*.  It uses
TX and RX FIFOs rather than mailboxes.

What is the current best practice for using NAPI? The models appear to
be quite different between drivers:

Uses NAPI for RX only:
 - rcan
 - xilinx
 - mscan
-  ti_hecc

Uses NAPI for RX and ERR:
 - flexcan
 - at91
 - m_can
 - ifi_canfd

Uses NAPI for the whole IRQ:
 - pch_can
 - c_can
 - ican3

Some others do not use NAPI at all, notably the venerable SJA1000 driver.

For new drivers, what scheme is recommended?

Kind regards.
Damien.


[1] http://www.ifi-pld.de/IP/NiosII_CAN/niosii_can.html
* Not to be confused with the recently-mainlined ifi-canfd core from
the same company.

Re: Recommended NAPI practices for new drivers

[Marc Kleine-Budde]

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On 09/29/2016 07:05 AM, Damien Dusha wrote:
> Dear All,
> 
> I am currently writing a driver for the IFI CAN IP Core [1]*.  It uses
> TX and RX FIFOs rather than mailboxes.
> 
> What is the current best practice for using NAPI? The models appear to
> be quite different between drivers:
> 
> Uses NAPI for RX only:
>  - rcan
>  - xilinx
>  - mscan
> -  ti_hecc
> 
> Uses NAPI for RX and ERR:
>  - flexcan
>  - at91
>  - m_can
>  - ifi_canfd
> 
> Uses NAPI for the whole IRQ:
>  - pch_can
>  - c_can
>  - ican3
> 
> Some others do not use NAPI at all, notably the venerable SJA1000 driver.
> 
> For new drivers, what scheme is recommended?

I'd go for RX-only NAPI.

Marc

BTW: I've a very old driver that's probably for this hardware.
Interested? It was written before socketcan was mainlined but never
adopted, as I didn't have access to the hardware anymore.

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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