virtio-input: add a virtio-mulitouch device

Add a virtio-multitouch device to the family of devices emulated by
virtio-input implementing the Multi-touch protocol as descripted here:

https://www.kernel.org/doc/html/latest/input/multi-touch-protocol.html?highlight=multi+touch

This patch just add the device itself, without connecting it to any
backends. The following patches will add a PCI-based multitouch device,
some helpers in "ui" and will enable the GTK3 backend to transpose
multi-touch events from the host to the guest.

Signed-off-by: Sergio Lopez <slp@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20230526112925.38794-4-slp@redhat.com>

hw/input/virtio-input-hid.c

@@ -16,9 +16,10 @@
 
 #include "standard-headers/linux/input.h"
 
-#define VIRTIO_ID_NAME_KEYBOARD "QEMU Virtio Keyboard"
-#define VIRTIO_ID_NAME_MOUSE    "QEMU Virtio Mouse"
-#define VIRTIO_ID_NAME_TABLET   "QEMU Virtio Tablet"
+#define VIRTIO_ID_NAME_KEYBOARD     "QEMU Virtio Keyboard"
+#define VIRTIO_ID_NAME_MOUSE        "QEMU Virtio Mouse"
+#define VIRTIO_ID_NAME_TABLET       "QEMU Virtio Tablet"
+#define VIRTIO_ID_NAME_MULTITOUCH   "QEMU Virtio MultiTouch"
 
 /* ----------------------------------------------------------------- */
 
@@ -30,6 +31,7 @@ static const unsigned short keymap_button[INPUT_BUTTON__MAX] = {
     [INPUT_BUTTON_WHEEL_DOWN]        = BTN_GEAR_DOWN,
     [INPUT_BUTTON_SIDE]              = BTN_SIDE,
     [INPUT_BUTTON_EXTRA]             = BTN_EXTRA,
+    [INPUT_BUTTON_TOUCH]             = BTN_TOUCH,
 };
 
 static const unsigned short axismap_rel[INPUT_AXIS__MAX] = {
@@ -42,6 +44,11 @@ static const unsigned short axismap_abs[INPUT_AXIS__MAX] = {
     [INPUT_AXIS_Y]                   = ABS_Y,
 };
 
+static const unsigned short axismap_tch[INPUT_AXIS__MAX] = {
+    [INPUT_AXIS_X]                   = ABS_MT_POSITION_X,
+    [INPUT_AXIS_Y]                   = ABS_MT_POSITION_Y,
+};
+
 /* ----------------------------------------------------------------- */
 
 static void virtio_input_extend_config(VirtIOInput *vinput,
@@ -81,6 +88,7 @@ static void virtio_input_handle_event(DeviceState *dev, QemuConsole *src,
     InputKeyEvent *key;
     InputMoveEvent *move;
     InputBtnEvent *btn;
+    InputMultiTouchEvent *mtt;
 
     switch (evt->type) {
     case INPUT_EVENT_KIND_KEY:
@@ -137,6 +145,24 @@ static void virtio_input_handle_event(DeviceState *dev, QemuConsole *src,
         event.value = cpu_to_le32(move->value);
         virtio_input_send(vinput, &event);
         break;
+    case INPUT_EVENT_KIND_MTT:
+        mtt = evt->u.mtt.data;
+        if (mtt->type == INPUT_MULTI_TOUCH_TYPE_DATA) {
+            event.type  = cpu_to_le16(EV_ABS);
+            event.code  = cpu_to_le16(axismap_tch[mtt->axis]);
+            event.value = cpu_to_le32(mtt->value);
+            virtio_input_send(vinput, &event);
+        } else {
+            event.type  = cpu_to_le16(EV_ABS);
+            event.code  = cpu_to_le16(ABS_MT_SLOT);
+            event.value = cpu_to_le32(mtt->slot);
+            virtio_input_send(vinput, &event);
+            event.type  = cpu_to_le16(EV_ABS);
+            event.code  = cpu_to_le16(ABS_MT_TRACKING_ID);
+            event.value = cpu_to_le32(mtt->tracking_id);
+            virtio_input_send(vinput, &event);
+        }
+        break;
     default:
         /* keep gcc happy */
         break;
@@ -515,12 +541,98 @@ static const TypeInfo virtio_tablet_info = {
 
 /* ----------------------------------------------------------------- */
 
+static QemuInputHandler virtio_multitouch_handler = {
+    .name  = VIRTIO_ID_NAME_MULTITOUCH,
+    .mask  = INPUT_EVENT_MASK_BTN | INPUT_EVENT_MASK_MTT,
+    .event = virtio_input_handle_event,
+    .sync  = virtio_input_handle_sync,
+};
+
+static struct virtio_input_config virtio_multitouch_config[] = {
+    {
+        .select    = VIRTIO_INPUT_CFG_ID_NAME,
+        .size      = sizeof(VIRTIO_ID_NAME_MULTITOUCH),
+        .u.string  = VIRTIO_ID_NAME_MULTITOUCH,
+    },{
+        .select    = VIRTIO_INPUT_CFG_ID_DEVIDS,
+        .size      = sizeof(struct virtio_input_devids),
+        .u.ids     = {
+            .bustype = const_le16(BUS_VIRTUAL),
+            .vendor  = const_le16(0x0627), /* same we use for usb hid devices */
+            .product = const_le16(0x0003),
+            .version = const_le16(0x0001),
+        },
+    },{
+        .select    = VIRTIO_INPUT_CFG_ABS_INFO,
+        .subsel    = ABS_MT_SLOT,
+        .size      = sizeof(virtio_input_absinfo),
+        .u.abs.min = const_le32(INPUT_EVENT_SLOTS_MIN),
+        .u.abs.max = const_le32(INPUT_EVENT_SLOTS_MAX),
+    },{
+        .select    = VIRTIO_INPUT_CFG_ABS_INFO,
+        .subsel    = ABS_MT_TRACKING_ID,
+        .size      = sizeof(virtio_input_absinfo),
+        .u.abs.min = const_le32(INPUT_EVENT_SLOTS_MIN),
+        .u.abs.max = const_le32(INPUT_EVENT_SLOTS_MAX),
+    },{
+        .select    = VIRTIO_INPUT_CFG_ABS_INFO,
+        .subsel    = ABS_MT_POSITION_X,
+        .size      = sizeof(virtio_input_absinfo),
+        .u.abs.min = const_le32(INPUT_EVENT_ABS_MIN),
+        .u.abs.max = const_le32(INPUT_EVENT_ABS_MAX),
+    },{
+        .select    = VIRTIO_INPUT_CFG_ABS_INFO,
+        .subsel    = ABS_MT_POSITION_Y,
+        .size      = sizeof(virtio_input_absinfo),
+        .u.abs.min = const_le32(INPUT_EVENT_ABS_MIN),
+        .u.abs.max = const_le32(INPUT_EVENT_ABS_MAX),
+    },
+    { /* end of list */ },
+};
+
+static void virtio_multitouch_init(Object *obj)
+{
+    VirtIOInputHID *vhid = VIRTIO_INPUT_HID(obj);
+    VirtIOInput *vinput = VIRTIO_INPUT(obj);
+    unsigned short abs_props[] = {
+        INPUT_PROP_DIRECT,
+    };
+    unsigned short abs_bits[] = {
+        ABS_MT_SLOT,
+        ABS_MT_TRACKING_ID,
+        ABS_MT_POSITION_X,
+        ABS_MT_POSITION_Y,
+    };
+
+    vhid->handler = &virtio_multitouch_handler;
+    virtio_input_init_config(vinput, virtio_multitouch_config);
+    virtio_input_extend_config(vinput, keymap_button,
+                               ARRAY_SIZE(keymap_button),
+                               VIRTIO_INPUT_CFG_EV_BITS, EV_KEY);
+    virtio_input_extend_config(vinput, abs_props,
+                               ARRAY_SIZE(abs_props),
+                               VIRTIO_INPUT_CFG_PROP_BITS, 0);
+    virtio_input_extend_config(vinput, abs_bits,
+                               ARRAY_SIZE(abs_bits),
+                               VIRTIO_INPUT_CFG_EV_BITS, EV_ABS);
+}
+
+static const TypeInfo virtio_multitouch_info = {
+    .name          = TYPE_VIRTIO_MULTITOUCH,
+    .parent        = TYPE_VIRTIO_INPUT_HID,
+    .instance_size = sizeof(VirtIOInputHID),
+    .instance_init = virtio_multitouch_init,
+};
+
+/* ----------------------------------------------------------------- */
+
 static void virtio_register_types(void)
 {
     type_register_static(&virtio_input_hid_info);
     type_register_static(&virtio_keyboard_info);
     type_register_static(&virtio_mouse_info);
     type_register_static(&virtio_tablet_info);
+    type_register_static(&virtio_multitouch_info);
 }
 
 type_init(virtio_register_types)

include/hw/virtio/virtio-input.h

@@ -24,10 +24,11 @@ OBJECT_DECLARE_TYPE(VirtIOInput, VirtIOInputClass,
 #define VIRTIO_INPUT_GET_PARENT_CLASS(obj) \
         OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_INPUT)
 
-#define TYPE_VIRTIO_INPUT_HID "virtio-input-hid-device"
-#define TYPE_VIRTIO_KEYBOARD  "virtio-keyboard-device"
-#define TYPE_VIRTIO_MOUSE     "virtio-mouse-device"
-#define TYPE_VIRTIO_TABLET    "virtio-tablet-device"
+#define TYPE_VIRTIO_INPUT_HID  "virtio-input-hid-device"
+#define TYPE_VIRTIO_KEYBOARD   "virtio-keyboard-device"
+#define TYPE_VIRTIO_MOUSE      "virtio-mouse-device"
+#define TYPE_VIRTIO_TABLET     "virtio-tablet-device"
+#define TYPE_VIRTIO_MULTITOUCH "virtio-multitouch-device"
 
 OBJECT_DECLARE_SIMPLE_TYPE(VirtIOInputHID, VIRTIO_INPUT_HID)
 #define VIRTIO_INPUT_HID_GET_PARENT_CLASS(obj) \