of/irq: Don't ignore interrupt-controller when interrupt-map failed

Since 041284181226 ("of/irq: Allow matching of an interrupt-map local
to an interrupt controller"), the irq code favors using an interrupt-map
over a interrupt-controller property if both are available, while the
earlier behaviour was to ignore the interrupt-map altogether.

However, we now end-up with the opposite behaviour, which is to
ignore the interrupt-controller property even if the interrupt-map
fails to match its input. This new behaviour breaks the AmigaOne
X1000 machine, which ships with an extremely "creative" (read:
broken) device tree.

Fix this by allowing the interrupt-controller property to be selected
when interrupt-map fails to match anything.

Fixes: 041284181226 ("of/irq: Allow matching of an interrupt-map local to an interrupt controller")
Reported-by: Christian Zigotzky <chzigotzky@xenosoft.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/78308692-02e6-9544-4035-3171a8e1e6d4@xenosoft.de
Link: https://lore.kernel.org/r/20211112143644.434995-1-maz@kernel.org
Cc: Bjorn Helgaas <bhelgaas@google.com>

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index 32be5a0..b10f015 100644 (file)
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -161,9 +161,10 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
                 * if it is then we are done, unless there is an
                 * interrupt-map which takes precedence.
                 */
+               bool intc = of_property_read_bool(ipar, "interrupt-controller");
+
                imap = of_get_property(ipar, "interrupt-map", &imaplen);
-               if (imap == NULL &&
-                   of_property_read_bool(ipar, "interrupt-controller")) {
+               if (imap == NULL && intc) {
                        pr_debug(" -> got it !\n");
                        return 0;
                }
@@ -244,8 +245,20 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
 
                        pr_debug(" -> imaplen=%d\n", imaplen);
                }
-               if (!match)
+               if (!match) {
+                       if (intc) {
+                               /*
+                                * The PASEMI Nemo is a known offender, so
+                                * let's only warn for anyone else.
+                                */
+                               WARN(!IS_ENABLED(CONFIG_PPC_PASEMI),
+                                    "%pOF interrupt-map failed, using interrupt-controller\n",
+                                    ipar);
+                               return 0;
+                       }
+
                        goto fail;
+               }
 
                /*
                 * Successfully parsed an interrrupt-map translation; copy new