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SubjectRe: [PATCH v3] of/irq: introduce of_irq_init
On Thu, Sep 22, 2011 at 09:21:13PM -0500, Rob Herring wrote:
> From: Rob Herring <rob.herring@calxeda.com>
>
> 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@calxeda.com>
> Cc: Grant Likely <grant.likely@secretlab.ca>

Looking really good, comments below...

> ---
> Changes from v2:
> - add missing kfree's found by Jamie
> - Implement Grant's comments to simplify the init loop
> - fix function comments

Nit: put changelog above the s-o-b lines so that it appears in the git
commit text.

>
> drivers/of/irq.c | 106 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/of_irq.h | 3 +
> 2 files changed, 109 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/of/irq.c b/drivers/of/irq.c
> index 6a5b5e7..aedd39b 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 +388,107 @@ 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. */

nit: weird indenting

> + 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_tail(&desc->list, &intc_desc_list);
> + }
> + if (list_empty(&intc_desc_list))
> + return;

This test in unnecessary

> +
> + /*
> + * 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 (!match || !match->data) {

match will always be !NULL. If match_data is NULL; something is
seriously wrong and the code should WARN().

> + 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_debug("of_irq_init: children remain, but no parents\n");

This is an error condition. Use pr_err()

> + 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
>


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