Subject: [PATCH v4] of/irq: introduce of_irq_init

From: [email-masked] (Rob Herring)
Date: Tue, 27 Sep 2011 08:03:51 -0500

Grant,

On 09/26/2011 08:53 PM, Grant Likely wrote:
> On Mon, Sep 26, 2011 at 02:24:43PM -0500, Rob Herring wrote:
>> From: Rob Herring <[email-masked]>
>>
>> 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.
>>
>> Changes in v4:
>> - Drop unnecessary empty list check
>> - Be more verbose on errors
>> - Simplify "if (!desc) WARN_ON(1)" to "if (WARN_ON(!desc))"
>>
>> Changes in v3:
>> - add missing kfree's found by Jamie
>> - Implement Grant's comments to simplify the init loop
>> - fix function comments
>>
>> Changes in v2:
>> - Complete re-write of list searching code from Grant Likely
>>
>> Signed-off-by: Rob Herring <[email-masked]>
>> Cc: Grant Likely <[email-masked]>
> 
> Looks good to me.  Merged.
> 

I'm dependent on this and things in rmk's tree for initial highbank
support, so should this series go in thru arm-soc tree? Several others
are dependent on this as well.

Rob

> g.
> 
>> ---
>>  drivers/of/irq.c       |  107 ++++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/of_irq.h |    3 +
>>  2 files changed, 110 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
>> index 6a5b5e7..6d3dd39 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 +388,108 @@ 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;
>> +};
>> +
>> +/**
>> + * of_irq_init - Scan and init matching interrupt controllers in DT
>> + * @matches: 0 terminated array of nodes to match and init function to call
>> + *
>> + * This function scans the device tree for matching interrupt controller nodes,
>> + * and calls their initialization functions in order with parents first.
>> + */
>> +void __init of_irq_init(const struct of_device_id *matches)
>> +{
>> +	struct device_node *np, *parent = NULL;
>> +	struct intc_desc *desc, *temp_desc;
>> +	struct list_head intc_desc_list, 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 (WARN_ON(!desc))
>> +			goto err;
>> +
>> +		desc->dev = np;
>> +		desc->interrupt_parent = of_irq_find_parent(np);
>> +		list_add_tail(&desc->list, &intc_desc_list);
>> +	}
>> +
>> +	/*
>> +	 * 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;
>> +			of_irq_init_cb_t irq_init_cb;
>> +
>> +			if (desc->interrupt_parent != parent)
>> +				continue;
>> +
>> +			list_del(&desc->list);
>> +			match = of_match_node(matches, desc->dev);
>> +			if (WARN(!match->data,
>> +			    "of_irq_init: no init function for %s\n",
>> +			    match->compatible)) {
>> +				kfree(desc);
>> +				continue;
>> +			}
>> +
>> +			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) {
>> +				kfree(desc);
>> +				continue;
>> +			}
>> +
>> +			/*
>> +			 * 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);
>> +		}
>> +
>> +		/* Get the next pending parent that might have children */
>> +		desc = list_first_entry(&intc_parent_list, typeof(*desc), list);
>> +		if (list_empty(&intc_parent_list) || !desc) {
>> +			pr_err("of_irq_init: children remain, but no parents\n");
>> +			break;
>> +		}
>> +		list_del(&desc->list);
>> +		parent = desc->dev;
>> +		kfree(desc);
>> +	}
>> +
>> +	list_for_each_entry_safe(desc, temp_desc, &intc_parent_list, list) {
>> +		list_del(&desc->list);
>> +		kfree(desc);
>> +	}
>> +err:
>> +	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..d0307ee 100644
>> --- a/include/linux/of_irq.h
>> +++ b/include/linux/of_irq.h
>> @@ -33,6 +33,8 @@ struct of_irq {
>>  	u32 specifier[OF_MAX_IRQ_SPEC]; /* Specifier copy */
>>  };
>>  
>> +typedef int (*of_irq_init_cb_t)(struct device_node *, struct device_node *);
>> +
>>  /*
>>   * Workarounds only applied to 32bit powermac machines
>>   */
>> @@ -73,6 +75,7 @@ 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
>>