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Commit fe17a42e authored by Marc Zyngier's avatar Marc Zyngier Committed by Thomas Gleixner
Browse files

irqdomain: Let irq_domain_mapping display hierarchical domains 



Hierarchical domains seem to be hard to grasp, and a number of
aspiring kernel hackers find them utterly discombobulating.

In order to ease their pain, let's make them appear in
/sys/kernel/debug/irq_domain_mapping, such as the following:

   96  0x81808  MSI    0x          (null) RADIX   MSI
   96+ 0x00063  GICv2m 0xffff8003ee116980 RADIX   GICv2m
   96+ 0x00063  GICv2  0xffff00000916bfd8 LINEAR  GICv2

[output compressed to fit in a commit log]

This shows that IRQ96 is implemented by a stack of three domains,
the + sign indicating the stacking.

Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/20170512115538.10767-2-marc.zyngier@arm.com


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 08332893

kernel/irq/irqdomain.c

+43 −25
Original line number Diff line number Diff line
@@ -746,13 +746,54 @@ unsigned int irq_find_mapping(struct irq_domain *domain, 
EXPORT_SYMBOL_GPL(irq_find_mapping);



#ifdef CONFIG_IRQ_DOMAIN_DEBUG

static void virq_debug_show_one(struct seq_file *m, struct irq_desc *desc)

{

	struct irq_domain *domain;

	struct irq_data *data;



	domain = desc->irq_data.domain;

	data = &desc->irq_data;



	while (domain) {

		unsigned int irq = data->irq;

		unsigned long hwirq = data->hwirq;

		struct irq_chip *chip;

		bool direct;



		if (data == &desc->irq_data)

			seq_printf(m, "%5d  ", irq);

		else

			seq_printf(m, "%5d+ ", irq);

		seq_printf(m, "0x%05lx  ", hwirq);



		chip = irq_data_get_irq_chip(data);

		seq_printf(m, "%-15s  ", (chip && chip->name) ? chip->name : "none");



		seq_printf(m, data ? "0x%p  " : "  %p  ",

			   irq_data_get_irq_chip_data(data));



		seq_printf(m, "   %c    ", (desc->action && desc->action->handler) ? '*' : ' ');

		direct = (irq == hwirq) && (irq < domain->revmap_direct_max_irq);

		seq_printf(m, "%6s%-8s  ",

			   (hwirq < domain->revmap_size) ? "LINEAR" : "RADIX",

			   direct ? "(DIRECT)" : "");

		seq_printf(m, "%s\n", domain->name);

#ifdef CONFIG_IRQ_DOMAIN_HIERARCHY

		domain = domain->parent;

		data = data->parent_data;

#else

		domain = NULL;

#endif

	}

}



static int virq_debug_show(struct seq_file *m, void *private)

{

	unsigned long flags;

	struct irq_desc *desc;

	struct irq_domain *domain;

	struct radix_tree_iter iter;

	void *data, **slot;

	void **slot;

	int i;



	seq_printf(m, " %-16s  %-6s  %-10s  %-10s  %s\n",
@@ -782,30 +823,7 @@ static int virq_debug_show(struct seq_file *m, void *private) 
			continue;



		raw_spin_lock_irqsave(&desc->lock, flags);

		domain = desc->irq_data.domain;



		if (domain) {

			struct irq_chip *chip;

			int hwirq = desc->irq_data.hwirq;

			bool direct;



			seq_printf(m, "%5d  ", i);

			seq_printf(m, "0x%05x  ", hwirq);



			chip = irq_desc_get_chip(desc);

			seq_printf(m, "%-15s  ", (chip && chip->name) ? chip->name : "none");



			data = irq_desc_get_chip_data(desc);

			seq_printf(m, data ? "0x%p  " : "  %p  ", data);



			seq_printf(m, "   %c    ", (desc->action && desc->action->handler) ? '*' : ' ');

			direct = (i == hwirq) && (i < domain->revmap_direct_max_irq);

			seq_printf(m, "%6s%-8s  ",

				   (hwirq < domain->revmap_size) ? "LINEAR" : "RADIX",

				   direct ? "(DIRECT)" : "");

			seq_printf(m, "%s\n", desc->irq_data.domain->name);

		}



		virq_debug_show_one(m, desc);

		raw_spin_unlock_irqrestore(&desc->lock, flags);

	}