Re: [PATCH 2/3] of/irq: introduce of_irq_init

[Jamie Iles]

Hi Rob,

On Tue, Sep 20, 2011 at 03:24:03PM -0500, Rob Herring wrote:
> From: Rob Herring <rob.herring@xxxxxxxxxxx>
> 
> of_irq_init will scan the devicetree for matching interrupt controller
> nodes. Then it calls an initialization function for each found controller
> in the proper order with parent nodes initialized before child nodes.
> 
> Based on initial pseudo code from Grant Likely.
> 
> Signed-off-by: Rob Herring <rob.herring@xxxxxxxxxxx>
> Cc: Grant Likely <grant.likely@xxxxxxxxxxxx>
> ---
>  drivers/of/irq.c       |  114 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/of_irq.h |    1 +
>  2 files changed, 115 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 6a5b5e7..1d51bc7 100644
> --- a/drivers/of/irq.c
> +++ b/drivers/of/irq.c
> @@ -19,10 +19,12 @@
>   */
>  
>  #include <linux/errno.h>
> +#include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
>  #include <linux/of_irq.h>
>  #include <linux/string.h>
> +#include <linux/slab.h>
>  
>  /* For archs that don't support NO_IRQ (such as x86), provide a dummy value */
>  #ifndef NO_IRQ
> @@ -386,3 +388,115 @@ int of_irq_to_resource_table(struct device_node *dev, struct resource *res,
>  
>  	return i;
>  }
> +
> +struct intc_desc {
> +	struct list_head	list;
> +	struct device_node	*dev;
> +	struct device_node	*interrupt_parent;
> +};
> +
> +typedef int (*irq_init_cb_t)(struct device_node *, struct device_node *);
> +
> +/**
> + * of_irq_init - Scan the device tree for matching interrupt controllers and
> + * call their initialization functions in order with parents first.
> + * @matches: 0 terminated array of nodes to match and initialization function
> + * to call on match
> + */
> +void __init of_irq_init(const struct of_device_id *matches)
> +{
> +	struct device_node *np;
> +	struct intc_desc *desc;
> +	struct intc_desc *temp_desc;
> +	struct intc_desc *parent_desc = NULL;
> +	struct list_head intc_desc_list;
> +	struct list_head intc_parent_list;
> +
> +	INIT_LIST_HEAD(&intc_desc_list);
> +	INIT_LIST_HEAD(&intc_parent_list);
> +
> +	for_each_matching_node(np, matches) {
> +		if (!of_find_property(np, "interrupt-controller", NULL))
> +			continue;
> +		/* Here, we allocate and populate an intc_desc with the node
> +		* pointer, interrupt-parent device_node etc. */
> +		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
> +		if (!desc) {
> +			WARN_ON(1);
> +			goto err;
> +		}
> +		desc->dev = np;
> +		desc->interrupt_parent = of_irq_find_parent(np);
> +		list_add(&desc->list, &intc_desc_list);
> +	}
> +	if (list_empty(&intc_desc_list))
> +		return;
> +
> +	/*
> +	 * The root irq controller is the one without an interrupt-parent.
> +	 * That one goes first, followed by the controllers that reference it,
> +	 * followed by the ones that reference the 2nd level controllers, etc
> +	 */
> +	while (!list_empty(&intc_desc_list)) {
> +		/*
> +		 * Process all controllers with the current 'parent'.
> +		 * First pass will be looking for NULL as the parent.
> +		 * The assumption is that NULL parent means a root controller.
> +		 */
> +		list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
> +			const struct of_device_id *match;
> +			int ret;
> +			irq_init_cb_t irq_init_cb;
> +
> +			if (parent_desc &&
> +				(desc->interrupt_parent != parent_desc->dev))
> +				continue;
> +
> +			list_del(&desc->list);
> +			match = of_match_node(matches, desc->dev);
> +			if (!match || !match->data)
> +				continue;

Doesn't this case need to kfree(desc)?

> +
> +			pr_debug("of_irq_init: init %s @ %p, parent %p\n",
> +				 match->compatible,
> +				 desc->dev, desc->interrupt_parent);
> +			irq_init_cb = match->data;
> +			ret = irq_init_cb(desc->dev, desc->interrupt_parent);
> +			if (ret)
> +				continue;

and here?

> +
> +			/*
> +			 * This one is now set up; add it to the parent list so
> +			 * its children can get processed in a subsequent pass.
> +			 */
> +			list_add_tail(&desc->list, &intc_parent_list);
> +		}
> +		/*
> +		 * All the direct children for the current parent are
> +		 * processed, so free the parent now.
> +		 */
> +		if (parent_desc)
> +			kfree(parent_desc);
> +
> +		/* Get the next pending parent that might have children */
> +		parent_desc = list_first_entry(&intc_parent_list,
> +					       typeof(*parent_desc), list);
> +		if (list_empty(&intc_parent_list) || !parent_desc) {
> +			pr_debug("of_irq_init: children remain, but no parents\n");
> +			goto err;
> +		}
> +
> +		list_del(&parent_desc->list);
> +	}
> +	return;
> +
> +err:
> +	list_for_each_entry_safe(desc, temp_desc, &intc_parent_list, list) {
> +		list_del(&desc->list);
> +		kfree(desc);
> +	}
> +	list_for_each_entry_safe(desc, temp_desc, &intc_desc_list, list) {
> +		list_del(&desc->list);
> +		kfree(desc);
> +	}
> +}
> diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
> index cd2e61c..032d76c 100644
> --- a/include/linux/of_irq.h
> +++ b/include/linux/of_irq.h
> @@ -73,6 +73,7 @@ extern int of_irq_to_resource_table(struct device_node *dev,
>  		struct resource *res, int nr_irqs);
>  extern struct device_node *of_irq_find_parent(struct device_node *child);
>  
> +extern void of_irq_init(const struct of_device_id *matches);
>  
>  #endif /* CONFIG_OF_IRQ */
>  #endif /* CONFIG_OF */
> -- 
> 1.7.5.4
> 
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