Re: [V4 PATCH 4/6] device property: Introduces device_dma_is_coherent()

[Suravee Suthikulanit]

On 5/20/2015 5:28 AM, Will Deacon wrote:
> On Fri, May 15, 2015 at 10:23:12PM +0100, Suravee Suthikulpanit wrote:
> > Currently, device drivers, which support both OF and ACPI,
> > need to call two separate APIs, of_dma_is_coherent() and
> > acpi_dma_is_coherent()) to determine device coherency attribute.
> >
> > This patch simplifies this process by introducing a new device
> > property API, device_dma_is_coherent(), which calls the appropriate
> > interface based on the booting architecture.
> >
> > Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@xxxxxxx>
> > CC: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> > ---
> >   drivers/base/property.c  | 12 ++++++++++++
> >   include/linux/property.h |  2 ++
> >   2 files changed, 14 insertions(+)
> >
> > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > index 1d0b116..8123c6e 100644
> > --- a/drivers/base/property.c
> > +++ b/drivers/base/property.c
> > @@ -14,6 +14,7 @@
> >   #include <linux/export.h>
> >   #include <linux/kernel.h>
> >   #include <linux/of.h>
> > +#include <linux/of_address.h>
> >   #include <linux/property.h>
> >
> >   /**
> > @@ -519,3 +520,14 @@ unsigned int device_get_child_node_count(struct device *dev)
> >   	return count;
> >   }
> >   EXPORT_SYMBOL_GPL(device_get_child_node_count);
> > +
> > +bool device_dma_is_coherent(struct device *dev)
> > +{
> > +	if (IS_ENABLED(CONFIG_OF) && dev->of_node)
> > +		return of_dma_is_coherent(dev->of_node);
> > +	else if (has_acpi_companion(dev))
> > +		return acpi_dma_is_coherent(acpi_node(dev->fwnode));
>
> I don't think you need the has_acpi_companion check, as acpi_node handles
> this and acpi_dma_is_coherent(NULL) returns false.
>
> Will
You are right.

Thanks,

Suravee

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