[PATCH] of/platform: Initialise default DMA masks

[PATCH] of/platform: Initialise default DMA masks

[Robin Murphy]

When of_dma_configure() was first born in 591c1ee465ce ("of: configure
the platform device dma parameters"), everything DMA-related was
factored out of of_platform_device_create_pdata() as seemed appropriate
at the time. However, now that of_dma_configure() has grown into the
generic handler for processing DMA-related properties from DT for all
kinds of devices, it is no longer an appropriate place to be doing
OF-platform-specific business. Since there are still plenty of platform
drivers not setting their own masks and depending on the bus default,
let's reinstate that inialisation in the OF-platform code itself, and
restore the long-standing status quo from 0589342c2794 ("of: set
dma_mask to point to coherent_dma_mask")

CC: Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
CC: Frank Rowand <frowand.list-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
---

This shouldn't strictly depend on the changes currently queued in the
dma-mapping tree, so should be OK to go through the DT tree in parallel.
Ideally we'd fix all DMA-capable drivers to set their masks correctly,
but in the short term everyone's going to get cross about -rc1 not
booting...

Robin.

 drivers/of/platform.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index 6925d993e1f0..7ba90c290a42 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -185,6 +185,9 @@ static struct platform_device *of_platform_device_create_pdata(
 	if (!dev)
 		goto err_clear_flag;
 
+	dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	if (!dev->dev.dma_mask)
+		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
 	dev->dev.bus = &platform_bus_type;
 	dev->dev.platform_data = platform_data;
 	of_msi_configure(&dev->dev, dev->dev.of_node);
-- 
2.17.1.dirty

Re: [PATCH] of/platform: Initialise default DMA masks

[Christoph Hellwig]

On Fri, Jul 27, 2018 at 03:14:15PM +0100, Robin Murphy wrote:
> This shouldn't strictly depend on the changes currently queued in the
> dma-mapping tree, so should be OK to go through the DT tree in parallel.
> Ideally we'd fix all DMA-capable drivers to set their masks correctly,
> but in the short term everyone's going to get cross about -rc1 not
> booting...

I'd prefer to pick this up through the dma-mapping tree, and in fact
move it before the bus_dma_mask changes just to keep a bisectable
tree.

Re: [PATCH] of/platform: Initialise default DMA masks

[Robin Murphy]

On 27/07/18 15:20, Christoph Hellwig wrote:
> On Fri, Jul 27, 2018 at 03:14:15PM +0100, Robin Murphy wrote:
>> This shouldn't strictly depend on the changes currently queued in the
>> dma-mapping tree, so should be OK to go through the DT tree in parallel.
>> Ideally we'd fix all DMA-capable drivers to set their masks correctly,
>> but in the short term everyone's going to get cross about -rc1 not
>> booting...
> 
> I'd prefer to pick this up through the dma-mapping tree, and in fact
> move it before the bus_dma_mask changes just to keep a bisectable
> tree.

Sure, if Rob and Frank are OK with that I don't mind either way.

Thanks,
Robin.

Re: [PATCH] of/platform: Initialise default DMA masks

[Rob Herring]

On Fri, Jul 27, 2018 at 8:18 AM Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org> wrote:
>
> On 27/07/18 15:20, Christoph Hellwig wrote:
> > On Fri, Jul 27, 2018 at 03:14:15PM +0100, Robin Murphy wrote:
> >> This shouldn't strictly depend on the changes currently queued in the
> >> dma-mapping tree, so should be OK to go through the DT tree in parallel.
> >> Ideally we'd fix all DMA-capable drivers to set their masks correctly,
> >> but in the short term everyone's going to get cross about -rc1 not
> >> booting...
> >
> > I'd prefer to pick this up through the dma-mapping tree, and in fact
> > move it before the bus_dma_mask changes just to keep a bisectable
> > tree.
>
> Sure, if Rob and Frank are OK with that I don't mind either way.

NP.

Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Re: [PATCH] of/platform: Initialise default DMA masks

[Christoph Hellwig]

On Fri, Jul 27, 2018 at 10:50:34AM -0600, Rob Herring wrote:
> On Fri, Jul 27, 2018 at 8:18 AM Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org> wrote:
> >
> > On 27/07/18 15:20, Christoph Hellwig wrote:
> > > On Fri, Jul 27, 2018 at 03:14:15PM +0100, Robin Murphy wrote:
> > >> This shouldn't strictly depend on the changes currently queued in the
> > >> dma-mapping tree, so should be OK to go through the DT tree in parallel.
> > >> Ideally we'd fix all DMA-capable drivers to set their masks correctly,
> > >> but in the short term everyone's going to get cross about -rc1 not
> > >> booting...
> > >
> > > I'd prefer to pick this up through the dma-mapping tree, and in fact
> > > move it before the bus_dma_mask changes just to keep a bisectable
> > > tree.
> >
> > Sure, if Rob and Frank are OK with that I don't mind either way.
> 
> NP.
> 
> Acked-by: Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>

Ok, applied so that it gets into the next linux-next.