issues calling of_platform_bus_probe() twice

issues calling of_platform_bus_probe() twice

[Kumar Gala]

Guys,

Are you aware of any reason that we can't call of_platform_bus_probe() or multiple times.  Timur's run into an issue in which all devices don't get registered properly if we call of_platform_bus_probe() times with different of_device_id struct's.

- k

Re: issues calling of_platform_bus_probe() twice

[Benjamin Herrenschmidt]

On Fri, 2012-03-16 at 16:21 -0500, Kumar Gala wrote:
> Guys,
> 
> Are you aware of any reason that we can't call of_platform_bus_probe()
> or multiple times.  Timur's run into an issue in which all devices
> don't get registered properly if we call of_platform_bus_probe() times
> with different of_device_id struct's.

Nothing comes to mind... Grant ?

Cheers,
Ben.

Re: issues calling of_platform_bus_probe() twice

[Grant Likely]

On Sat, 17 Mar 2012 08:23:54 +1100, Benjamin Herrenschmidt <benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org> wrote:
> On Fri, 2012-03-16 at 16:21 -0500, Kumar Gala wrote:
> > Guys,
> > 
> > Are you aware of any reason that we can't call of_platform_bus_probe()
> > or multiple times.  Timur's run into an issue in which all devices
> > don't get registered properly if we call of_platform_bus_probe() times
> > with different of_device_id struct's.
> 
> Nothing comes to mind... Grant ?

Neither for me.  Should work.

g.

Re: issues calling of_platform_bus_probe() twice

[Tabi Timur-B04825]

Grant Likely wrote:
>>> >  >  Are you aware of any reason that we can't call of_platform_bus_probe()
>>> >  >  or multiple times.  Timur's run into an issue in which all devices
>>> >  >  don't get registered properly if we call of_platform_bus_probe() times
>>> >  >  with different of_device_id struct's.
>> >
>> >  Nothing comes to mind... Grant ?
> Neither for me.  Should work.

I posted a work-around patch here:

http://patchwork.ozlabs.org/patch/128533/

Without this patch, drivers cannot probe on DMA *channels*, or any other 
grandchildren of the root node.

-- 
Timur Tabi
Linux kernel developer at Freescale

Re: issues calling of_platform_bus_probe() twice

[Benjamin Herrenschmidt]

On Sat, 2012-03-17 at 13:35 +0000, Tabi Timur-B04825 wrote:
> >>> >  >  Are you aware of any reason that we can't call
> of_platform_bus_probe()
> >>> >  >  or multiple times.  Timur's run into an issue in which all
> devices
> >>> >  >  don't get registered properly if we call
> of_platform_bus_probe() times
> >>> >  >  with different of_device_id struct's.
> >> >
> >> >  Nothing comes to mind... Grant ?
> > Neither for me.  Should work.
> 
> I posted a work-around patch here:
> 
> http://patchwork.ozlabs.org/patch/128533/
> 
> Without this patch, drivers cannot probe on DMA *channels*, or any
> other 
> grandchildren of the root node. 

Why don't you track down the actual bug instead ?

Cheers,
Ben.

Re: issues calling of_platform_bus_probe() twice

[Tabi Timur-B04825]

Benjamin Herrenschmidt wrote:
> Why don't you track down the actual bug instead ?

I was hoping that someone who is very familiar with the code would take a 
look.  I don't know the OF layer that well.

-- 
Timur Tabi
Linux kernel developer at Freescale

Re: issues calling of_platform_bus_probe() twice

[Grant Likely]

On Sat, 17 Mar 2012 13:35:02 +0000, Tabi Timur-B04825 <B04825@freescale.com> wrote:
> Grant Likely wrote:
> >>> >  >  Are you aware of any reason that we can't call of_platform_bus_probe()
> >>> >  >  or multiple times.  Timur's run into an issue in which all devices
> >>> >  >  don't get registered properly if we call of_platform_bus_probe() times
> >>> >  >  with different of_device_id struct's.
> >> >
> >> >  Nothing comes to mind... Grant ?
> > Neither for me.  Should work.
> 
> I posted a work-around patch here:
> 
> http://patchwork.ozlabs.org/patch/128533/
> 
> Without this patch, drivers cannot probe on DMA *channels*, or any other 
> grandchildren of the root node.

That's because you're using it wrong.  of_platform_bus_probe() creates
platform devices at the starting level and every level below it as
described by the bus ids.  It is illegal to call of_platform_bus_probe()
twice at the same level in the DT.

g.

Re: issues calling of_platform_bus_probe() twice

[Tabi Timur-B04825]

Grant Likely wrote:
> That's because you're using it wrong.  of_platform_bus_probe() creates
> platform devices at the starting level and every level below it as
> described by the bus ids.  It is illegal to call of_platform_bus_probe()
> twice at the same level in the DT.

Well, *I* am not using it wrong.  Notice that my patch fixes (or works 
around) the commit that *did* do it wrong:

http://patchwork.ozlabs.org/patch/126289/

-- 
Timur Tabi
Linux kernel developer at Freescale

Re: issues calling of_platform_bus_probe() twice

[Grant Likely]

On Sun, 18 Mar 2012 16:14:23 +0000, Tabi Timur-B04825 <B04825@freescale.com> wrote:
> Grant Likely wrote:
> > That's because you're using it wrong.  of_platform_bus_probe() creates
> > platform devices at the starting level and every level below it as
> > described by the bus ids.  It is illegal to call of_platform_bus_probe()
> > twice at the same level in the DT.
> 
> Well, *I* am not using it wrong.  Notice that my patch fixes (or works 
> around) the commit that *did* do it wrong:
> 
> http://patchwork.ozlabs.org/patch/126289/

Fair enough; I just wanted to point out that there it can only dig as
deep into the tree as is specified by the bus ids.  The exact problem
wasn't calling the function twice, but rather trying to call the
function twice from the same level of the tree.

BTW, I also recommend moving to of_platform_populate() for new code.
I think the behaviour is more consistent for fdt platforms and it
is more convenient for devices that are children of the root.

g.