[RFC v2 3/6] irq: bypass: Extend skeleton for ARM forwarding control

[Eric Auger <eric.auger@xxxxxxxxxx>]

- [add,del]_[consumer,producer] updated to takes both the consumer and
  producer handles. This is requested to combine info from both,
  typically to link the source irq owned by the producer with the gsi
  owned by the consumer (forwarded IRQ setup).
- new methods are added:
  x stop/resume: Those are needed for forwarding since the state change
    requires to entermingle actions at consumer, producer.
  x consumer update for posted interrupts
- On handshake, we now call connect, disconnect which features the more
  complex sequence.
- add irq on producer side

Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>

---

v1 -> v2:
- remove vfio_device, kvm, gsi, opaque fields included in v1 except common
- all those in can be retrieved with container_of in callbacks
---
 include/linux/irqbypass.h | 19 ++++++++++++++++---
 kernel/irq/bypass.c       | 44 ++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 56 insertions(+), 7 deletions(-)

diff --git a/include/linux/irqbypass.h b/include/linux/irqbypass.h
index 718508e..8f62235 100644
--- a/include/linux/irqbypass.h
+++ b/include/linux/irqbypass.h
@@ -3,17 +3,30 @@
 
 #include <linux/list.h>
 
+struct irq_bypass_consumer;
+
 struct irq_bypass_producer {
 	struct list_head node;
 	void *token;
-	/* TBD */
+	int irq; /* linux irq */
+	void (*stop)(struct irq_bypass_producer *);
+	void (*resume)(struct irq_bypass_producer *);
+	void (*add_consumer)(struct irq_bypass_producer *,
+			     struct irq_bypass_consumer *);
+	void (*del_consumer)(struct irq_bypass_producer *,
+			     struct irq_bypass_consumer *);
 };
 
 struct irq_bypass_consumer {
 	struct list_head node;
 	void *token;
-	void (*add_producer)(struct irq_bypass_producer *);
-	void (*del_producer)(struct irq_bypass_producer *);
+	void (*stop)(struct irq_bypass_consumer *);
+	void (*resume)(struct irq_bypass_consumer *);
+	void (*add_producer)(struct irq_bypass_consumer *,
+			     struct irq_bypass_producer *);
+	void (*del_producer)(struct irq_bypass_consumer *,
+			     struct irq_bypass_producer *);
+	void (*update)(struct irq_bypass_consumer *);
 };
 
 int irq_bypass_register_producer(struct irq_bypass_producer *);
diff --git a/kernel/irq/bypass.c b/kernel/irq/bypass.c
index 5d0f92b..efadbe5 100644
--- a/kernel/irq/bypass.c
+++ b/kernel/irq/bypass.c
@@ -19,6 +19,42 @@ static LIST_HEAD(producers);
 static LIST_HEAD(consumers);
 static DEFINE_MUTEX(lock);
 
+/* lock must be hold when calling connect */
+static void connect(struct irq_bypass_producer *prod,
+		    struct irq_bypass_consumer *cons)
+{
+	if (prod->stop)
+		prod->stop(prod);
+	if (cons->stop)
+		cons->stop(cons);
+	if (prod->add_consumer)
+		prod->add_consumer(prod, cons);
+	if (cons->add_producer)
+		cons->add_producer(cons, prod);
+	if (cons->resume)
+		cons->resume(cons);
+	if (prod->resume)
+		prod->resume(prod);
+}
+
+/* lock must be hold when calling disconnect */
+static void disconnect(struct irq_bypass_producer *prod,
+		       struct irq_bypass_consumer *cons)
+{
+	if (prod->stop)
+		prod->stop(prod);
+	if (cons->stop)
+		cons->stop(cons);
+	if (cons->del_producer)
+		cons->del_producer(cons, prod);
+	if (prod->del_consumer)
+		prod->del_consumer(prod, cons);
+	if (cons->resume)
+		cons->resume(cons);
+	if (prod->resume)
+		prod->resume(prod);
+}
+
 int irq_bypass_register_producer(struct irq_bypass_producer *producer)
 {
 	struct irq_bypass_producer *tmp;
@@ -38,7 +74,7 @@ int irq_bypass_register_producer(struct irq_bypass_producer *producer)
 
 	list_for_each_entry(consumer, &consumers, node) {
 		if (consumer->token == producer->token) {
-			consumer->add_producer(producer);
+			connect(producer, consumer);
 			break;
 		}
 	}
@@ -56,7 +92,7 @@ void irq_bypass_unregister_producer(struct irq_bypass_producer *producer)
 
 	list_for_each_entry(consumer, &consumers, node) {
 		if (consumer->token == producer->token) {
-			consumer->del_producer(producer);
+			disconnect(producer, consumer);
 			break;
 		}
 	}
@@ -86,7 +122,7 @@ int irq_bypass_register_consumer(struct irq_bypass_consumer *consumer)
 
 	list_for_each_entry(producer, &producers, node) {
 		if (producer->token == consumer->token) {
-			consumer->add_producer(producer);
+			connect(producer, consumer);
 			break;
 		}
 	}
@@ -104,7 +140,7 @@ void irq_bypass_unregister_consumer(struct irq_bypass_consumer *consumer)
 
 	list_for_each_entry(producer, &producers, node) {
 		if (producer->token == consumer->token) {
-			consumer->del_producer(producer);
+			disconnect(producer, consumer);
 			break;
 		}
 	}
-- 
1.9.1

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