[PATCH 2/2] of/irq: do irq resolution in platform_get_irq

[Tony Lindgren]

* Rob Herring <robherring2 at gmail.com> [140423 15:58]:
> From: Rob Herring <robh at kernel.org>
> 
> Currently we get the following kind of errors if we try to use interrupt
> phandles to irqchips that have not yet initialized:
> 
> irq: no irq domain found for /ocp/pinmux at 48002030 !
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at drivers/of/platform.c:171 of_device_alloc+0x144/0x184()
> Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.12.0-00038-g42a9708 #1012
> (show_stack+0x14/0x1c)
> (dump_stack+0x6c/0xa0)
> (warn_slowpath_common+0x64/0x84)
> (warn_slowpath_null+0x1c/0x24)
> (of_device_alloc+0x144/0x184)
> (of_platform_device_create_pdata+0x44/0x9c)
> (of_platform_bus_create+0xd0/0x170)
> (of_platform_bus_create+0x12c/0x170)
> (of_platform_populate+0x60/0x98)
> 
> This is because we're wrongly trying to populate resources that are not
> yet available. It's perfectly valid to create irqchips dynamically, so
> let's fix up the issue by resolving the interrupt resources when
> platform_get_irq is called.
> 
> And then we also need to accept the fact that some irqdomains do not
> exist that early on, and only get initialized later on. So we can
> make the current WARN_ON into just into a pr_debug().
> 
> We still attempt to populate irq resources when we create the devices.
> This allows current drivers which don't use platform_get_irq to continue
> to function. Once all drivers are fixed, this code can be removed.
> 
> Suggested-by: Russell King <linux at arm.linux.org.uk>
> Signed-off-by: Rob Herring <robh at kernel.org>
> Signed-off-by: Tony Lindgren <tony at atomide.com>

Great, works for me. Hopefully this patch is non-intrusive enough for
people for the -rc cycle too?

Tested-by: Tony Lindgren <tony at atomide.com>

> ---
>  drivers/base/platform.c |  7 ++++++-
>  drivers/of/irq.c        | 26 ++++++++++++++++++++++++++
>  drivers/of/platform.c   |  4 +++-
>  include/linux/of_irq.h  |  7 ++++++-
>  4 files changed, 41 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index e714709..5b47210 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 +88,11 @@ 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_IRQ) && dev->dev.of_node)
> +		return of_irq_get(dev->dev.of_node, num);
> +
> +	r = platform_get_resource(dev, IORESOURCE_IRQ, num);
>  
>  	return r ? r->start : -ENXIO;
>  #endif
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 9bcf2cf..ca01893 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -380,6 +380,32 @@ int of_irq_to_resource(struct device_node *dev, int index, struct resource *r)
>  EXPORT_SYMBOL_GPL(of_irq_to_resource);
>  
>  /**
> + * of_irq_get - Decode a node's IRQ and return it as a Linux irq number
> + * @dev: pointer to device tree node
> + * @index: zero-based index of the irq
> + *
> + * Returns Linux irq number on success, or -EPROBE_DEFER if the irq domain
> + * is not yet created.
> + *
> + */
> +int of_irq_get(struct device_node *dev, int index)
> +{
> +	int rc;
> +	struct of_phandle_args oirq;
> +	struct irq_domain *domain;
> +
> +	rc = of_irq_parse_one(dev, index, &oirq);
> +	if (rc)
> +		return rc;
> +
> +	domain = irq_find_host(oirq.np);
> +	if (!domain)
> +		return -EPROBE_DEFER;
> +
> +	return irq_create_of_mapping(&oirq);
> +}
> +
> +/**
>   * of_irq_count - Count the number of IRQs a node uses
>   * @dev: pointer to device tree node
>   */
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 404d1da..bd47fbc 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -168,7 +168,9 @@ struct platform_device *of_device_alloc(struct device_node *np,
>  			rc = of_address_to_resource(np, i, res);
>  			WARN_ON(rc);
>  		}
> -		WARN_ON(of_irq_to_resource_table(np, res, num_irq) != num_irq);
> +		if (of_irq_to_resource_table(np, res, num_irq) != num_irq)
> +			pr_debug("not all legacy IRQ resources mapped for %s\n",
> +				 np->name);
>  	}
>  
>  	dev->dev.of_node = of_node_get(np);
> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> index 3f23b44..bc9e51a 100644
> --- a/include/linux/of_irq.h
> +++ b/include/linux/of_irq.h
> @@ -34,21 +34,26 @@ static inline int of_irq_parse_oldworld(struct device_node *device, int index,
>  extern int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq);
>  extern int of_irq_parse_one(struct device_node *device, int index,
>  			  struct of_phandle_args *out_irq);
> -extern unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data);
>  extern int of_irq_to_resource(struct device_node *dev, int index,
>  			      struct resource *r);
>  extern int of_irq_to_resource_table(struct device_node *dev,
>  		struct resource *res, int nr_irqs);
> +extern unsigned int irq_create_of_mapping(struct of_phandle_args *irq_data);
>  
>  extern void of_irq_init(const struct of_device_id *matches);
>  
>  #ifdef CONFIG_OF_IRQ
>  extern int of_irq_count(struct device_node *dev);
> +extern int of_irq_get(struct device_node *dev, int index);
>  #else
>  static inline int of_irq_count(struct device_node *dev)
>  {
>  	return 0;
>  }
> +static inline int of_irq_get(struct device_node *dev, int index)
> +{
> +	return 0;
> +}
>  #endif
>  
>  #if defined(CONFIG_OF)
> -- 
> 1.9.1
>