genirq/generic_chip: Add irq_unmap callback

Without this patch irq_domain_disassociate() cannot properly release the
interrupt. In fact, 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 an implementation of an unmap function that can be
called by irq_domain_disassociate().

[ tglx: Made the function static and removed the export as we have neither
  	a prototype nor a modular user. ]

Fixes: 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/579F5C5A.2070507@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 21 insertions, 0 deletions

diff --git a/kernel/irq/generic-chip.c b/kernel/irq/generic-chip.c
index 11ad73b39d2e..a3a392097804 100644
--- a/kernel/irq/generic-chip.c
+++ b/kernel/irq/generic-chip.c
@@ -414,8 +414,29 @@ int irq_map_generic_chip(struct irq_domain *d, unsigned int virq,
         return 0;
 }
 
+static 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;
+        unsigned int hw_irq = data->hwirq;
+        struct irq_chip_generic *gc;
+        int irq_idx;
+
+        gc = irq_get_domain_generic_chip(d, hw_irq);
+        if (!gc)
+                return;
+
+        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);
+
+}
+
 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);