Re: [RFC 07/22] block: ide: call device_probe() after scanning

Simon Glass
2021-10-11T14:55:56Z

Hi Takahiro,

On Sun, 10 Oct 2021 at 19:43, AKASHI Takahiro
<takahiro.akashi@linaro.org> wrote:
>
> On Sun, Oct 10, 2021 at 08:14:13AM -0600, Simon Glass wrote:
> > On Thu, 30 Sept 2021 at 23:03, AKASHI Takahiro
> > <takahiro.akashi@linaro.org> wrote:
> > >
> > > Every time an ide bus/port is scanned and a new device is detected,
> > > we want to call device_probe() as it will give us a chance to run additional
> > > post-processings for some purposes.
> > >
> > > In particular, support for creating partitions on a device will be added.
> > >
> > > Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> > > ---
> > > drivers/block/ide.c | 6 ++++++
> > > 1 file changed, 6 insertions(+)
> > >
> >
> > Reviewed-by: Simon Glass <sjg@chromium.org>
> >
> > I'm starting to wonder if you can create a function that does the
> > probe and unbind? Something in the blk interface, perhaps? It would
> > reduce the duplicated code and provide a standard way of bringing up a
> > new device.
>
> That is exactly what Ilias suggested but I'm a bit declined to do :)
>
> Common 'scanning' code looks like:
> blk_create_devicef(... , &dev);
> desc = dev_get_uclass_data(dev);
> initialize some members in desc as well as device-specific info --- (A)
> (now dev can be accessible.)
> ret = device_probe(dev);
> if (ret) {
> de-initialize *dev* --- (B)
> device_unbind()
> }
>
> Basically (B) is supposed to undo (A) which may or may not exist,
> depending on types of block devices.
>
> So I'm not 100% sure that a combination of device_probe() and device_unbind()
> will fit to all the device types.
> (The only cases that I have noticed are fsl_sata.c and sata_sil.c. Both
> have their own xxx_unbind_device(), but they simply call device_remove() and
> device_unbind(), though. So no worry?)

Yes I agree it would be a very strange function. But at least it would
have the benefit of grouping the code together under a particular
name, something like blk_back_out_bind(), but that's not a good
name....it just feels like this might get refactored in the future and
having the code in one place might be handy.

Regards,
Simon