Re: [RESEND v4 4/6] Documentation: misc-devices: Add Documentation for dw-xdata-pcie driver

Krzysztof Wilczyński
2021-02-08T23:12:37Z

Hi Gustavo,

[...]
> > When I do the following:
> >
> > # echo 1 > /sys/kernel/dw-xdata-pcie/write
> > # echo 1 > /sys/kernel/dw-xdata-pcie/stop
> > # cat /sys/kernel/dw-xdata-pcie/write
> >
> > Would output from cat above simply show "0 MB/s" then? I wonder how
> > someone using this new driver could tell whether "write" or "read"
> > traffic generation has been enabled aside of reading the sysfs files,
> > would adding "/sys/kernel/dw-xdata-pcie/active" be an overkill here?
> >
> > What do you think?
>
> Yes, it would display 0 MB/s. This driver is to be used mainly by the
> Synopsys DesignWare HW prototyping team. I don't think the general public
> will be interested or can use this driver, because requires a special HW
> block available only for this prototype.

Got it.

> I tried to reduce to the minimal the interfaces, to avoid possible
> confusion. For instance, even the /sys/kernel/dw-xdata-pcie/stop
> interface could be avoided, because on the driver unloading or changing
> the between write or read it calls the stop procedure.

Oh, OK.

> Due to the nature of the HW block, it only can allow the write or the
> read at some given moment, therefore based on the last command enable
> write or read, we know which mode is this driving working.
> This driver will be used by the testing team on their automation scripts,
> thus they will know exactly the sequence input.
>
> Anyway, thanks for your feedback.

Thank you for taking the time to add more details for me. Much
appreciated.

Krzysztof