of/irq: Add a quirk for controllers with their own definition of interrupt-map

Since commit 041284181226 ("of/irq: Allow matching of an interrupt-map
local to an interrupt controller"), a handful of interrupt controllers
have stopped working correctly. This is due to the DT exposing a
non-sensical interrupt-map property, and their drivers relying on the
kernel ignoring this property.

Since we cannot realistically fix this terrible behaviour, add a quirk
for the limited set of devices that have implemented this monster,
and document that this is a pretty bad practice.

Fixes: 041284181226 ("of/irq: Allow matching of an interrupt-map local to an interrupt controller")
Cc: Rob Herring <robh@kernel.org>
Cc: John Crispin <john@phrozen.org>
Cc: Biwen Li <biwen.li@nxp.com>
Cc: Chris Brandt <chris.brandt@renesas.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Sander Vanheule <sander@svanheule.net>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20211201114102.13446-1-maz@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>

diff --git a/drivers/of/irq.c b/drivers/of/irq.c
index b10f015b2e3775a930c6580502cdeb618c3e7cf3..2b07677a386b7c860d275c6145f7480536640e63 100644 (file)
--- a/drivers/of/irq.c
+++ b/drivers/of/irq.c
@@ -76,6 +76,26 @@ struct device_node *of_irq_find_parent(struct device_node *child)
 }
 EXPORT_SYMBOL_GPL(of_irq_find_parent);
 
 }
 EXPORT_SYMBOL_GPL(of_irq_find_parent);
 

+/*
+ * These interrupt controllers abuse interrupt-map for unspeakable
+ * reasons and rely on the core code to *ignore* it (the drivers do
+ * their own parsing of the property).
+ *
+ * If you think of adding to the list for something *new*, think
+ * again. There is a high chance that you will be sent back to the
+ * drawing board.
+ */
+static const char * const of_irq_imap_abusers[] = {
+       "CBEA,platform-spider-pic",
+       "sti,platform-spider-pic",
+       "realtek,rtl-intc",
+       "fsl,ls1021a-extirq",
+       "fsl,ls1043a-extirq",
+       "fsl,ls1088a-extirq",
+       "renesas,rza1-irqc",
+       NULL,
+};
+

 /**
  * of_irq_parse_raw - Low level interrupt tree parsing
  * @addr:      address specifier (start of "reg" property of the device) in be32 format
 /**
  * of_irq_parse_raw - Low level interrupt tree parsing
  * @addr:      address specifier (start of "reg" property of the device) in be32 format


@@ -159,12 +179,15 @@ int of_irq_parse_raw(const __be32 *addr, struct of_phandle_args *out_irq)
                /*
                 * Now check if cursor is an interrupt-controller and
                 * if it is then we are done, unless there is an
                /*
                 * Now check if cursor is an interrupt-controller and
                 * if it is then we are done, unless there is an

-                * interrupt-map which takes precedence.
+                * interrupt-map which takes precedence except on one
+                * of these broken platforms that want to parse
+                * interrupt-map themselves for $reason.

                 */
                bool intc = of_property_read_bool(ipar, "interrupt-controller");
 
                imap = of_get_property(ipar, "interrupt-map", &imaplen);
                 */
                bool intc = of_property_read_bool(ipar, "interrupt-controller");
 
                imap = of_get_property(ipar, "interrupt-map", &imaplen);

-               if (imap == NULL && intc) {
+               if (intc &&
+                   (!imap || of_device_compatible_match(ipar, of_irq_imap_abusers))) {

                        pr_debug(" -> got it !\n");
                        return 0;
                }
                        pr_debug(" -> got it !\n");
                        return 0;
                }