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Diffstat (limited to 'arch/sparc/kernel/irq_64.c')
-rw-r--r--arch/sparc/kernel/irq_64.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/arch/sparc/kernel/irq_64.c b/arch/sparc/kernel/irq_64.c
index e289376198e..1c378d8e90c 100644
--- a/arch/sparc/kernel/irq_64.c
+++ b/arch/sparc/kernel/irq_64.c
@@ -323,17 +323,25 @@ static void sun4u_set_affinity(unsigned int virt_irq,
sun4u_irq_enable(virt_irq);
}
+/* Don't do anything. The desc->status check for IRQ_DISABLED in
+ * handler_irq() will skip the handler call and that will leave the
+ * interrupt in the sent state. The next ->enable() call will hit the
+ * ICLR register to reset the state machine.
+ *
+ * This scheme is necessary, instead of clearing the Valid bit in the
+ * IMAP register, to handle the case of IMAP registers being shared by
+ * multiple INOs (and thus ICLR registers). Since we use a different
+ * virtual IRQ for each shared IMAP instance, the generic code thinks
+ * there is only one user so it prematurely calls ->disable() on
+ * free_irq().
+ *
+ * We have to provide an explicit ->disable() method instead of using
+ * NULL to get the default. The reason is that if the generic code
+ * sees that, it also hooks up a default ->shutdown method which
+ * invokes ->mask() which we do not want. See irq_chip_set_defaults().
+ */
static void sun4u_irq_disable(unsigned int virt_irq)
{
- struct irq_handler_data *data = get_irq_chip_data(virt_irq);
-
- if (likely(data)) {
- unsigned long imap = data->imap;
- unsigned long tmp = upa_readq(imap);
-
- tmp &= ~IMAP_VALID;
- upa_writeq(tmp, imap);
- }
}
static void sun4u_irq_eoi(unsigned int virt_irq)
@@ -746,7 +754,8 @@ void handler_irq(int irq, struct pt_regs *regs)
desc = irq_desc + virt_irq;
- desc->handle_irq(virt_irq, desc);
+ if (!(desc->status & IRQ_DISABLED))
+ desc->handle_irq(virt_irq, desc);
bucket_pa = next_pa;
}