egvirt: linux-yocto: Add virtio_bt driver.

virtio-bt is not part of OASIS standard yet (v1.2) but Linux kernel has
driver for virtio transport for BT HCI.

Submit driver to meta-agl-devel since patch [1] is WIP and has a known
issue.

[1]: 0002-Bluetooth-virtio_bt-fix-device-removal.patch

Bug-AGL: SPEC-4363
Change-Id: Ib6851df24d430e991a4e9078345bef7e440fb6de
Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>

2 files changed, 85 insertions, 0 deletions

diff --git a/meta-egvirt/recipes-kernel/linux/linux-yocto/0002-Bluetooth-virtio_bt-fix-device-removal.patch b/meta-egvirt/recipes-kernel/linux/linux-yocto/0002-Bluetooth-virtio_bt-fix-device-removal.patch
new file mode 100644
index 00000000..8c33cab0
--- /dev/null
+++ b/meta-egvirt/recipes-kernel/linux/linux-yocto/0002-Bluetooth-virtio_bt-fix-device-removal.patch
@@ -0,0 +1,78 @@
+From 0eb8535f5991e658ef3a795b4124c04524ca8fc5 Mon Sep 17 00:00:00 2001
+From: "Michael S. Tsirkin" <mst@redhat.com>
+Date: Thu, 25 Nov 2021 12:44:48 -0500
+Subject: [PATCH] Bluetooth: virtio_bt: fix device removal
+
+Device removal is clearly out of virtio spec: it attempts to remove
+unused buffers from a VQ before invoking device reset. To fix, make
+open/close NOPs and do all cleanup/setup in probe/remove.
+
+The cost here is a single skb wasted on an unused bt device - which
+seems modest.
+
+NB: with this fix in place driver still suffers from a race condition if
+an interrupt triggers while device is being reset. Work on a fix for
+that issue is in progress.
+
+Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
+Upstream-Status: Submitted [https://lore.kernel.org/all/20211125174200.133230-1-mst@redhat.com/]
+---
+ drivers/bluetooth/virtio_bt.c | 18 ++++++++++++++++--
+ 1 file changed, 16 insertions(+), 2 deletions(-)
+
+diff --git a/drivers/bluetooth/virtio_bt.c b/drivers/bluetooth/virtio_bt.c
+index 076e4942a3f0..0ce1778babe6 100644
+--- a/drivers/bluetooth/virtio_bt.c
++++ b/drivers/bluetooth/virtio_bt.c
+@@ -50,8 +50,11 @@ static int virtbt_add_inbuf(struct virtio_bluetooth *vbt)
+ 
+ static int virtbt_open(struct hci_dev *hdev)
+ {
+-	struct virtio_bluetooth *vbt = hci_get_drvdata(hdev);
++	return 0;
++}
+ 
++static int virtbt_open_vdev(struct virtio_bluetooth *vbt)
++{
+ 	if (virtbt_add_inbuf(vbt) < 0)
+ 		return -EIO;
+ 
+@@ -61,7 +64,11 @@ static int virtbt_open(struct hci_dev *hdev)
+ 
+ static int virtbt_close(struct hci_dev *hdev)
+ {
+-	struct virtio_bluetooth *vbt = hci_get_drvdata(hdev);
++	return 0;
++}
++
++static int virtbt_close_vdev(struct virtio_bluetooth *vbt)
++{
+ 	int i;
+ 
+ 	cancel_work_sync(&vbt->rx);
+@@ -354,8 +361,14 @@ static int virtbt_probe(struct virtio_device *vdev)
+ 		goto failed;
+ 	}
+ 
++	virtio_device_ready(vdev);
++	if (virtbt_open_vdev(vbt))
++		goto open_failed;
++
+ 	return 0;
+ 
++open_failed:
++	hci_free_dev(hdev);
+ failed:
+ 	vdev->config->del_vqs(vdev);
+ 	return err;
+@@ -368,6 +381,7 @@ static void virtbt_remove(struct virtio_device *vdev)
+ 
+ 	hci_unregister_dev(hdev);
+ 	vdev->config->reset(vdev);
++	virtbt_close_vdev(vbt);
+ 
+ 	hci_free_dev(hdev);
+ 	vbt->hdev = NULL;
+-- 
+2.35.1
+
diff --git a/meta-egvirt/recipes-kernel/linux/linux-yocto/virtio_bt.cfg b/meta-egvirt/recipes-kernel/linux/linux-yocto/virtio_bt.cfg
new file mode 100644
index 00000000..154a05d5
--- /dev/null
+++ b/meta-egvirt/recipes-kernel/linux/linux-yocto/virtio_bt.cfg
@@ -0,0 +1,7 @@
+# Enable BT_VIRTIO ("Virtio Bluetooth driver") config located in menu
+#
+#     -> Networking support (NET [=y])                                                                                                                                                                                                  │  
+#       -> Bluetooth subsystem support (BT [=m])                                                                                                                                                                                        │  
+#         -> Bluetooth device drivers                                                                                                                                                                                                   │  
+#
+CONFIG_BT_VIRTIO=m