Without this patch irq_domain_disassociate() cannot properly release the
interrupt.
Indeed, irq_map_generic_chip() checks a bit on 'gc->installed' but said bit
is never cleared, only set.
Commit 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
added irq_map_generic_chip() function and also stated "This lacks a removal
function for now".
This commit provides with an implementation of an unmap function that can
be called by irq_domain_disassociate().
Fixes: 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
Signed-off-by: Sebastian Frias <s...@laposte.net>
---
This is required by loadable modules requesting IRQs.
In our case rmmod will perform free_irq() + irq_dispose_mapping().
Without the unmap call the module cannot request the IRQ after "rmmod"
because it is marked as "installed" by the first successful "insmod".
NOTE: While the proposed unmap() function attempts to undo as much things
as done by the map() function, I did not find a way to undo the following:
a) irq_gc_init_mask_cache(gc, dgc->gc_flags)
b) irq_set_lockdep_class(virq, &irq_nested_lock_class)
c) irq_modify_status(virq, dgc->irq_flags_to_clear, dgc->irq_flags_to_set)
Feel free to comment on that matter.
---
kernel/irq/generic-chip.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index abd286a..7b464cd 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -411,8 +411,34 @@ int irq_map_generic_chip(struct irq_domain *d, unsigned
int virq,
}
EXPORT_SYMBOL_GPL(irq_map_generic_chip);
+void irq_unmap_generic_chip(struct irq_domain *d, unsigned int virq)
+{
+ struct irq_data *data = irq_domain_get_irq_data(d, virq);
+ struct irq_domain_chip_generic *dgc = d->gc;
+ struct irq_chip_generic *gc;
+ unsigned int hw_irq = data->hwirq;
+ int chip_idx, irq_idx;
+
+ if (!d->gc)
+ return;
+
+ chip_idx = hw_irq / dgc->irqs_per_chip;
+ if (chip_idx >= dgc->num_chips)
+ return;
+ gc = dgc->gc[chip_idx];
+
+ irq_idx = hw_irq % dgc->irqs_per_chip;
+
+ clear_bit(irq_idx, &gc->installed);
+ irq_domain_set_info(d, virq, hw_irq,
+ &no_irq_chip, NULL, NULL, NULL, NULL);
+
+}
+EXPORT_SYMBOL_GPL(irq_unmap_generic_chip);
+
struct irq_domain_ops irq_generic_chip_ops = {
.map = irq_map_generic_chip,
+ .unmap = irq_unmap_generic_chip,
.xlate = irq_domain_xlate_onetwocell,
};
EXPORT_SYMBOL_GPL(irq_generic_chip_ops);
--
1.7.11.2
