firmware: arm_ffa: Add notification handling mechanism

With all the necessary plumbing in place, let us add handling the
notifications as part of schedule receiver interrupt handler. In order
to do so, we need to just register scheduling callback on behalf of the
driver partition.

Link: https://lore.kernel.org/r/20231005-ffa_v1-1_notif-v4-12-cddd3237809c@arm.comSigned-off-by: Sudeep Holla <sudeep.holla@arm.com>

drivers/firmware/arm_ffa/driver.c

@@ -103,6 +103,7 @@ struct ffa_drv_info {
 	unsigned int cpuhp_state;
 	struct ffa_pcpu_irq __percpu *irq_pcpu;
 	struct workqueue_struct *notif_pcpu_wq;
+	struct work_struct notif_pcpu_work;
 	struct work_struct irq_work;
 	struct xarray partition_info;
 	unsigned int partition_count;
@@ -633,6 +634,10 @@ static int ffa_notification_bitmap_destroy(void)
 #define MAX_IDS_32				10
 
 #define PER_VCPU_NOTIFICATION_FLAG		BIT(0)
+#define SECURE_PARTITION_BITMAP			BIT(0)
+#define NON_SECURE_VM_BITMAP			BIT(1)
+#define SPM_FRAMEWORK_BITMAP			BIT(2)
+#define NS_HYP_FRAMEWORK_BITMAP			BIT(3)
 
 static int ffa_notification_bind_common(u16 dst_id, u64 bitmap,
 					u32 flags, bool is_bind)
@@ -1050,6 +1055,54 @@ static int ffa_notify_send(struct ffa_device *dev, int notify_id,
 				    BIT(notify_id));
 }
 
+static void handle_notif_callbacks(u64 bitmap, enum notify_type type)
+{
+	int notify_id;
+	struct notifier_cb_info *cb_info = NULL;
+
+	for (notify_id = 0; notify_id <= FFA_MAX_NOTIFICATIONS && bitmap;
+	     notify_id++, bitmap >>= 1) {
+		if (!(bitmap & 1))
+			continue;
+
+		mutex_lock(&drv_info->notify_lock);
+		cb_info = notifier_hash_node_get(notify_id, type);
+		mutex_unlock(&drv_info->notify_lock);
+
+		if (cb_info && cb_info->cb)
+			cb_info->cb(notify_id, cb_info->cb_data);
+	}
+}
+
+static void notif_pcpu_irq_work_fn(struct work_struct *work)
+{
+	int rc;
+	struct ffa_notify_bitmaps bitmaps;
+
+	rc = ffa_notification_get(SECURE_PARTITION_BITMAP |
+				  SPM_FRAMEWORK_BITMAP, &bitmaps);
+	if (rc) {
+		pr_err("Failed to retrieve notifications with %d!\n", rc);
+		return;
+	}
+
+	handle_notif_callbacks(bitmaps.vm_map, NON_SECURE_VM);
+	handle_notif_callbacks(bitmaps.sp_map, SECURE_PARTITION);
+	handle_notif_callbacks(bitmaps.arch_map, FRAMEWORK);
+}
+
+static void
+ffa_self_notif_handle(u16 vcpu, bool is_per_vcpu, void *cb_data)
+{
+	struct ffa_drv_info *info = cb_data;
+
+	if (!is_per_vcpu)
+		notif_pcpu_irq_work_fn(&info->notif_pcpu_work);
+	else
+		queue_work_on(vcpu, info->notif_pcpu_wq,
+			      &info->notif_pcpu_work);
+}
+
 static const struct ffa_info_ops ffa_drv_info_ops = {
 	.api_version_get = ffa_api_version_get,
 	.partition_info_get = ffa_partition_info_get,
@@ -1154,6 +1207,13 @@ static void ffa_setup_partitions(void)
 	drv_info->partition_count = count;
 
 	kfree(pbuf);
+
+	/* Allocate for the host */
+	info = kzalloc(sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return;
+	xa_store(&drv_info->partition_info, drv_info->vm_id, info, GFP_KERNEL);
+	drv_info->partition_count++;
 }
 
 static void ffa_partitions_cleanup(void)
@@ -1294,6 +1354,7 @@ static int ffa_init_pcpu_irq(unsigned int irq)
 	}
 
 	INIT_WORK(&drv_info->irq_work, ffa_sched_recv_irq_work_fn);
+	INIT_WORK(&drv_info->notif_pcpu_work, notif_pcpu_irq_work_fn);
 	drv_info->notif_pcpu_wq = create_workqueue("ffa_pcpu_irq_notification");
 	if (!drv_info->notif_pcpu_wq)
 		return -EINVAL;
@@ -1352,7 +1413,11 @@ static int ffa_notifications_setup(void)
 	hash_init(drv_info->notifier_hash);
 	mutex_init(&drv_info->notify_lock);
 
-	return 0;
+	/* Register internal scheduling callback */
+	ret = ffa_sched_recv_cb_update(drv_info->vm_id, ffa_self_notif_handle,
+				       drv_info, true);
+	if (!ret)
+		return ret;
 cleanup:
 	ffa_notifications_cleanup();
 	return ret;