On Thu, 28 Nov 2013 16:46:23 +0100, Thierry Reding <thierry.reding@xxxxxxxxx> wrote:
> On Wed, Nov 27, 2013 at 03:56:29PM +0000, Grant Likely wrote:
> > On Mon, 25 Nov 2013 10:49:55 +0100, Thierry Reding <thierry.reding@xxxxxxxxx> wrote:
> > >
> > > I should maybe add: one issue that was raised during review of my
> > > initial patch series was that we'll also need to cope with situations
> > > like the following:
> > >
> > > 1) device's interrupt parent is probed (assigned IRQ base X)
> > > 2) device is probed (interrupt parent there, therefore gets
> > > assigned IRQ (X + z)
> > > 3) device in removed
> > > 4) device's interrupt parent is removed
> > > 5) device is probed (deferred because interrupt parent isn't
> > > there)
> > > 6) device's interrupt parent is probed (assigned IRQ base Y)
> > > 7) device is probed, gets assigned IRQ (Y + z)
> > >
> > > So not only do we have to track which resources are interrupt resources,
> > > but we also need to have them reassigned everytime the device is probed,
> > > therefore interrupt mappings need to be properly disposed and the values
> > > invalidated when probing is deferred or the device removed.
> >
> > Yes, that is a problem, but the only way to handle that is to always
> > recalcuate all resource references at probe time. I don't feel good
> > about handling that in the core. I'd rather move drivers away from
> > referencing the resources table directly and instead use an API. Then
> > the resources table could be missing entirely.
>
> Are you suggesting something like this?
>
> ---
>
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index 3a94b799f166..c894d1af3a5e 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -13,6 +13,7 @@
> #include <linux/string.h>
> #include <linux/platform_device.h>
> #include <linux/of_device.h>
> +#include <linux/of_irq.h>
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/dma-mapping.h>
> @@ -87,7 +88,12 @@ int platform_get_irq(struct platform_device *dev, unsigned int num)
> return -ENXIO;
> return dev->archdata.irqs[num];
> #else
> - struct resource *r = platform_get_resource(dev, IORESOURCE_IRQ, num);
> + struct resource *r;
> +
> + if (IS_ENABLED(CONFIG_OF) && dev->dev.of_node)
> + return irq_of_parse_and_map(dev->dev.of_node, num);
> +
> + r = platform_get_resource(dev, IORESOURCE_IRQ, num);
Yes. Or even more generically we could have a device_get_irq() function:
int device_get_irq(struct device *dev, unsigned int num)
{
if (IS_ENABLED(CONFIG_OF) && dev->of_node)
return irq_of_parse_and_map(dev->of_node, num);
/* An ACPI hook could go here */
return 0
}
It would be callable by any device driver, and platform_get_irq() could
call it too.
g.
--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
