linux-kernel - Re: [PATCH] drivers: of: Export of_reserved_mem_device

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Date:	Fri, 9 Jan 2015 16:29:43 -0600
From:	Rob Herring <robherring2@...il.com>
To:	"George G. Davis" <ggdavisiv@...il.com>
Cc:	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	"George G. Davis" <george_davis@...tor.com>
Subject: Re: [PATCH] drivers: of: Export of_reserved_mem_device_{init,release}

On Fri, Jan 9, 2015 at 4:05 PM, George G. Davis <ggdavisiv@...il.com> wrote:
> On Fri, Jan 09, 2015 at 01:33:10PM -0500, George G. Davis wrote:
>> On Fri, Jan 09, 2015 at 11:53:01AM -0600, Rob Herring wrote:
>> > On Fri, Jan 9, 2015 at 8:29 AM, George G. Davis <ggdavisiv@...il.com> wrote:
>> > > Export of_reserved_mem_device_{init,release} so that modules
>> > > can initialize and release their assigned per-device cma_area.
>> >
>> > I believe the original intent was for the core bus code to call these
>> > functions. While the commit adding them says "automated assignment"
>> > that part did not go in.
>>
>> I suspected that there may have been a bit of missing magic.  The only
>> use of these functions that I was able to find was in an earlier out of
>> tree patch series where these functions were called from the s5p-mfc
>> driver:
>>
>> http://lists.linaro.org/pipermail/linaro-mm-sig/2014-August/004140.html
>>
>> I agree that "automated assignment" via core bus code would be a better
>> solution but I don't know where to add the calls.
>
> How about something like the following for automated assignment?:

It seems Grant wasn't happy about the core code doing this[1]. So I
guess your original patch was okay except you should use
EXPORT_SYMBOL_GPL. I can fix that up if you agree.

Rob


[1] https://lkml.org/lkml/2014/3/2/30

>
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 9421fed..231b427 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -14,6 +14,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/of_device.h>
>  #include <linux/of_irq.h>
> +#include <linux/of_reserved_mem.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
>  #include <linux/dma-mapping.h>
> @@ -509,9 +510,12 @@ static int platform_drv_probe(struct device *_dev)
>
>         ret = dev_pm_domain_attach(_dev, true);
>         if (ret != -EPROBE_DEFER) {
> +               of_reserved_mem_device_init(_dev);
>                 ret = drv->probe(dev);
> -               if (ret)
> +               if (ret) {
> +                       of_reserved_mem_device_release(_dev);
>                         dev_pm_domain_detach(_dev, true);
> +               }
>         }
>
>         if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
> @@ -534,6 +538,7 @@ static int platform_drv_remove(struct device *_dev)
>         int ret;
>
>         ret = drv->remove(dev);
> +       of_reserved_mem_device_release(_dev);
>         dev_pm_domain_detach(_dev, true);
>
>         return ret;
>
>
> --
> Regards,
> George
>>
>> > As it stands, there are no in tree users of
>> > these functions.
>> >
>> > Marek, comments?
>>
>> Thanks!
>>
>> --
>> Regards,
>> George
>>
>> >
>> > Rob
>> >
>> > >
>> > > Signed-off-by: George G. Davis <george_davis@...tor.com>
>> > > ---
>> > >  drivers/of/of_reserved_mem.c | 2 ++
>> > >  1 file changed, 2 insertions(+)
>> > >
>> > > diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
>> > > index dc566b3..5eeb5b2 100644
>> > > --- a/drivers/of/of_reserved_mem.c
>> > > +++ b/drivers/of/of_reserved_mem.c
>> > > @@ -265,6 +265,7 @@ int of_reserved_mem_device_init(struct device *dev)
>> > >
>> > >         return ret;
>> > >  }
>> > > +EXPORT_SYMBOL(of_reserved_mem_device_init);
>> > >
>> > >  /**
>> > >   * of_reserved_mem_device_release() - release reserved memory device structures
>> > > @@ -289,3 +290,4 @@ void of_reserved_mem_device_release(struct device *dev)
>> > >
>> > >         rmem->ops->device_release(rmem, dev);
>> > >  }
>> > > +EXPORT_SYMBOL(of_reserved_mem_device_release);
>> > > --
>> > > 1.9.3
>> > >
--
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