From 4290b4b84961021bbba3fcbb76edd479180e3c78 Mon Sep 17 00:00:00 2001
From: Justin Hibbits <jhibbits@FreeBSD.org>
Date: Wed, 6 Feb 2019 03:52:14 +0000
Subject: [PATCH] powerpc: Bind IRQs to only one interrupt on QorIQ SoCs

The QorIQ SoCs don't actually support multicast interrupts, and the
references state explicitly that multicast is undefined behavior.  Avoid the
undefined behavior by binding to only a single CPU, using a quirk to
determine if this is necessary.

MFC after:	3 weeks
---
 sys/powerpc/include/openpicvar.h |  3 +++
 sys/powerpc/ofw/openpic_ofw.c    |  5 +++++
 sys/powerpc/powerpc/openpic.c    | 20 +++++++++++++++++++-
 3 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/sys/powerpc/include/openpicvar.h b/sys/powerpc/include/openpicvar.h
index 36b2c93342fa..52e25d7f7cc6 100644
--- a/sys/powerpc/include/openpicvar.h
+++ b/sys/powerpc/include/openpicvar.h
@@ -34,6 +34,8 @@
 
 #define OPENPIC_IRQMAX	256	/* h/w allows more */
 
+#define	OPENPIC_QUIRK_SINGLE_BIND	1	/* Bind interrupts to only 1 CPU */
+
 /* Names match the macros in openpicreg.h. */
 struct openpic_timer {
     	uint32_t	tcnt;
@@ -55,6 +57,7 @@ struct openpic_softc {
 	u_int		sc_ncpu;
 	u_int		sc_nirq;
 	int		sc_psim;
+	u_int		sc_quirks;
 
 	/* Saved states. */
 	uint32_t		sc_saved_config;
diff --git a/sys/powerpc/ofw/openpic_ofw.c b/sys/powerpc/ofw/openpic_ofw.c
index 6a66c8dce00b..ad550051c5bf 100644
--- a/sys/powerpc/ofw/openpic_ofw.c
+++ b/sys/powerpc/ofw/openpic_ofw.c
@@ -128,14 +128,19 @@ openpic_ofw_probe(device_t dev)
 static int
 openpic_ofw_attach(device_t dev)
 {
+	struct openpic_softc *sc;
 	phandle_t xref, node;
 
 	node = ofw_bus_get_node(dev);
+	sc = device_get_softc(dev);
 
 	if (OF_getencprop(node, "phandle", &xref, sizeof(xref)) == -1 &&
 	    OF_getencprop(node, "ibm,phandle", &xref, sizeof(xref)) == -1 &&
 	    OF_getencprop(node, "linux,phandle", &xref, sizeof(xref)) == -1)
 		xref = node;
+	
+	if (ofw_bus_is_compatible(dev, "fsl,mpic"))
+		sc->sc_quirks = OPENPIC_QUIRK_SINGLE_BIND;
 
 	return (openpic_common_attach(dev, xref));
 }
diff --git a/sys/powerpc/powerpc/openpic.c b/sys/powerpc/powerpc/openpic.c
index 6941c70ef704..8511d5be1f33 100644
--- a/sys/powerpc/powerpc/openpic.c
+++ b/sys/powerpc/powerpc/openpic.c
@@ -35,6 +35,7 @@
 #include <sys/proc.h>
 #include <sys/rman.h>
 #include <sys/sched.h>
+#include <sys/smp.h>
 
 #include <machine/bus.h>
 #include <machine/intr_machdep.h>
@@ -236,6 +237,7 @@ void
 openpic_bind(device_t dev, u_int irq, cpuset_t cpumask, void **priv __unused)
 {
 	struct openpic_softc *sc;
+	uint32_t mask;
 
 	/* If we aren't directly connected to the CPU, this won't work */
 	if (dev != root_pic)
@@ -247,7 +249,23 @@ openpic_bind(device_t dev, u_int irq, cpuset_t cpumask, void **priv __unused)
 	 * XXX: openpic_write() is very special and just needs a 32 bits mask.
 	 * For the moment, just play dirty and get the first half word.
 	 */
-	openpic_write(sc, OPENPIC_IDEST(irq), cpumask.__bits[0] & 0xffffffff);
+	mask = cpumask.__bits[0] & 0xffffffff;
+	if (sc->sc_quirks & OPENPIC_QUIRK_SINGLE_BIND) {
+		int i = mftb() % CPU_COUNT(&cpumask);
+		int cpu, ncpu;
+
+		ncpu = 0;
+		CPU_FOREACH(cpu) {
+			if (!(mask & (1 << cpu)))
+				continue;
+			if (ncpu == i)
+				break;
+			ncpu++;
+		}
+		mask &= (1 << cpu);
+	}
+
+	openpic_write(sc, OPENPIC_IDEST(irq), mask);
 }
 
 void