[PATCH V2 3/6] vDPA: implement IRQ offloading helpers in vDPA core

[Zhu Lingshan <lingshan.zhu@intel.com>]

This commit implements IRQ offloading helpers in vDPA core by
introducing two couple of functions:

vdpa_alloc_vq_irq() and vdpa_free_vq_irq(): request irq and free
irq, will setup irq offloading.

vdpa_setup_irq() and vdpa_unsetup_irq(): supportive functions,
will call vhost_vdpa helpers.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
---
 drivers/vdpa/vdpa.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/vdpa.h | 13 +++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index ff6562f..cce4d91 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -163,6 +163,48 @@ void vdpa_unregister_driver(struct vdpa_driver *drv)
 }
 EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
 
+static void vdpa_setup_irq(struct vdpa_device *vdev, int qid, int irq)
+{
+	struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
+
+	if (drv->setup_vq_irq)
+		drv->setup_vq_irq(vdev, qid, irq);
+}
+
+static void vdpa_unsetup_irq(struct vdpa_device *vdev, int qid)
+{
+	struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
+
+	if (drv->unsetup_vq_irq)
+		drv->unsetup_vq_irq(vdev, qid);
+}
+
+int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
+		      unsigned int irq, irq_handler_t handler,
+		      unsigned long irqflags, const char *devname, void *dev_id,
+		      int qid)
+{
+	int ret;
+
+	ret = devm_request_irq(dev, irq, handler, irqflags, devname, dev_id);
+	if (ret)
+		dev_err(dev, "Failed to request irq for vq %d\n", qid);
+	else
+		vdpa_setup_irq(vdev, qid, irq);
+
+	return ret;
+
+}
+EXPORT_SYMBOL_GPL(vdpa_alloc_vq_irq);
+
+void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
+			 int qid, void *dev_id)
+{
+	devm_free_irq(dev, irq, dev_id);
+	vdpa_unsetup_irq(vdev, qid);
+}
+EXPORT_SYMBOL_GPL(vdpa_free_vq_irq);
+
 static int vdpa_init(void)
 {
 	return bus_register(&vdpa_bus);
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 239db79..7d64d83 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -220,17 +220,30 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
 
 int vdpa_register_device(struct vdpa_device *vdev);
 void vdpa_unregister_device(struct vdpa_device *vdev);
+/* request irq for a vq, setup irq offloading if its a vhost_vdpa vq */
+int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
+		      unsigned int irq, irq_handler_t handler,
+		      unsigned long irqflags, const char *devname, void *dev_id,
+		      int qid);
+/* free irq for a vq, unsetup irq offloading if its a vhost_vdpa vq */
+void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
+		      int qid, void *dev_id);
+
 
 /**
  * vdpa_driver - operations for a vDPA driver
  * @driver: underlying device driver
  * @probe: the function to call when a device is found.  Returns 0 or -errno.
  * @remove: the function to call when a device is removed.
+ * @setup_vq_irq: setup irq offloading for a vhost_vdpa vq.
+ * @unsetup_vq_irq: unsetup offloading for a vhost_vdpa vq.
  */
 struct vdpa_driver {
 	struct device_driver driver;
 	int (*probe)(struct vdpa_device *vdev);
 	void (*remove)(struct vdpa_device *vdev);
+	void (*setup_vq_irq)(struct vdpa_device *vdev, int qid, int irq);
+	void (*unsetup_vq_irq)(struct vdpa_device *vdev, int qid);
 };
 
 #define vdpa_register_driver(drv) \
-- 
1.8.3.1