virtio-input: core code & base class [device]

This patch adds virtio-input support to qemu.  It brings a abstract
base class providing core support, other classes can build on it to
actually implement input devices.

virtio-input basically sends linux input layer events (evdev) over
virtio.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 282 insertions, 0 deletions

diff --git a/hw/input/virtio-input.c b/hw/input/virtio-input.c
new file mode 100644
index 0000000..e615c5c
--- /dev/null
+++ b/hw/input/virtio-input.c
@@ -0,0 +1,282 @@
+/*
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu/iov.h"
+
+#include "hw/qdev.h"
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-input.h"
+
+#include "standard-headers/linux/input.h"
+
+/* ----------------------------------------------------------------- */
+
+void virtio_input_send(VirtIOInput *vinput, virtio_input_event *event)
+{
+    VirtQueueElement elem;
+    unsigned have, need;
+    int i, len;
+
+    /* queue up events ... */
+    if (vinput->qindex == vinput->qsize) {
+        vinput->qsize++;
+        vinput->queue = realloc(vinput->queue, vinput->qsize *
+                                sizeof(virtio_input_event));
+    }
+    vinput->queue[vinput->qindex++] = *event;
+
+    /* ... until we see a report sync ... */
+    if (event->type != cpu_to_le16(EV_SYN) ||
+        event->code != cpu_to_le16(SYN_REPORT)) {
+        return;
+    }
+
+    /* ... then check available space ... */
+    need = sizeof(virtio_input_event) * vinput->qindex;
+    virtqueue_get_avail_bytes(vinput->evt, &have, NULL, need, 0);
+    if (have < need) {
+        vinput->qindex = 0;
+        fprintf(stderr, "%s: ENOSPC in vq, dropping events\n", __func__);
+        return;
+    }
+
+    /* ... and finally pass them to the guest */
+    for (i = 0; i < vinput->qindex; i++) {
+        if (!virtqueue_pop(vinput->evt, &elem)) {
+            /* should not happen, we've checked for space beforehand */
+            fprintf(stderr, "%s: Huh?  No vq elem available ...\n", __func__);
+            return;
+        }
+        len = iov_from_buf(elem.in_sg, elem.in_num,
+                           0, vinput->queue+i, sizeof(virtio_input_event));
+        virtqueue_push(vinput->evt, &elem, len);
+    }
+    virtio_notify(VIRTIO_DEVICE(vinput), vinput->evt);
+    vinput->qindex = 0;
+}
+
+static void virtio_input_handle_evt(VirtIODevice *vdev, VirtQueue *vq)
+{
+    /* nothing */
+}
+
+static void virtio_input_handle_sts(VirtIODevice *vdev, VirtQueue *vq)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
+    VirtIOInput *vinput = VIRTIO_INPUT(vdev);
+    virtio_input_event event;
+    VirtQueueElement elem;
+    int len;
+
+    while (virtqueue_pop(vinput->sts, &elem)) {
+        memset(&event, 0, sizeof(event));
+        len = iov_to_buf(elem.out_sg, elem.out_num,
+                         0, &event, sizeof(event));
+        if (vic->handle_status) {
+            vic->handle_status(vinput, &event);
+        }
+        virtqueue_push(vinput->sts, &elem, len);
+    }
+    virtio_notify(vdev, vinput->sts);
+}
+
+static virtio_input_config *virtio_input_find_config(VirtIOInput *vinput,
+                                                     uint8_t select,
+                                                     uint8_t subsel)
+{
+    VirtIOInputConfig *cfg;
+
+    QTAILQ_FOREACH(cfg, &vinput->cfg_list, node) {
+        if (select == cfg->config.select &&
+            subsel == cfg->config.subsel) {
+            return &cfg->config;
+        }
+    }
+    return NULL;
+}
+
+void virtio_input_add_config(VirtIOInput *vinput,
+                             virtio_input_config *config)
+{
+    VirtIOInputConfig *cfg;
+
+    if (virtio_input_find_config(vinput, config->select, config->subsel)) {
+        /* should not happen */
+        fprintf(stderr, "%s: duplicate config: %d/%d\n",
+                __func__, config->select, config->subsel);
+        abort();
+    }
+
+    cfg = g_new0(VirtIOInputConfig, 1);
+    cfg->config = *config;
+    QTAILQ_INSERT_TAIL(&vinput->cfg_list, cfg, node);
+}
+
+void virtio_input_init_config(VirtIOInput *vinput,
+                              virtio_input_config *config)
+{
+    int i = 0;
+
+    QTAILQ_INIT(&vinput->cfg_list);
+    while (config[i].select) {
+        virtio_input_add_config(vinput, config + i);
+        i++;
+    }
+}
+
+void virtio_input_idstr_config(VirtIOInput *vinput,
+                               uint8_t select, const char *string)
+{
+    virtio_input_config id;
+
+    if (!string) {
+        return;
+    }
+    memset(&id, 0, sizeof(id));
+    id.select = select;
+    id.size = snprintf(id.u.string, sizeof(id.u.string), "%s", string);
+    virtio_input_add_config(vinput, &id);
+}
+
+static void virtio_input_get_config(VirtIODevice *vdev, uint8_t *config_data)
+{
+    VirtIOInput *vinput = VIRTIO_INPUT(vdev);
+    virtio_input_config *config;
+
+    config = virtio_input_find_config(vinput, vinput->cfg_select,
+                                      vinput->cfg_subsel);
+    if (config) {
+        memcpy(config_data, config, vinput->cfg_size);
+    } else {
+        memset(config_data, 0, vinput->cfg_size);
+    }
+}
+
+static void virtio_input_set_config(VirtIODevice *vdev,
+                                    const uint8_t *config_data)
+{
+    VirtIOInput *vinput = VIRTIO_INPUT(vdev);
+    virtio_input_config *config = (virtio_input_config *)config_data;
+
+    vinput->cfg_select = config->select;
+    vinput->cfg_subsel = config->subsel;
+    virtio_notify_config(vdev);
+}
+
+static uint32_t virtio_input_get_features(VirtIODevice *vdev, uint32_t f)
+{
+    return f;
+}
+
+static void virtio_input_set_status(VirtIODevice *vdev, uint8_t val)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
+    VirtIOInput *vinput = VIRTIO_INPUT(vdev);
+
+    if (val & VIRTIO_CONFIG_S_DRIVER_OK) {
+        if (!vinput->active) {
+            vinput->active = true;
+            if (vic->change_active) {
+                vic->change_active(vinput);
+            }
+        }
+    }
+}
+
+static void virtio_input_reset(VirtIODevice *vdev)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(vdev);
+    VirtIOInput *vinput = VIRTIO_INPUT(vdev);
+
+    if (vinput->active) {
+        vinput->active = false;
+        if (vic->change_active) {
+            vic->change_active(vinput);
+        }
+    }
+}
+
+static void virtio_input_device_realize(DeviceState *dev, Error **errp)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(dev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    VirtIOInput *vinput = VIRTIO_INPUT(dev);
+    VirtIOInputConfig *cfg;
+    Error *local_err = NULL;
+
+    if (vic->realize) {
+        vic->realize(dev, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+
+    virtio_input_idstr_config(vinput, VIRTIO_INPUT_CFG_ID_SERIAL,
+                              vinput->input.serial);
+
+    QTAILQ_FOREACH(cfg, &vinput->cfg_list, node) {
+        if (vinput->cfg_size < cfg->config.size) {
+            vinput->cfg_size = cfg->config.size;
+        }
+    }
+    vinput->cfg_size += 8;
+    assert(vinput->cfg_size <= sizeof(virtio_input_config));
+
+    virtio_init(vdev, "virtio-input", VIRTIO_ID_INPUT,
+                vinput->cfg_size);
+    vinput->evt = virtio_add_queue(vdev, 64, virtio_input_handle_evt);
+    vinput->sts = virtio_add_queue(vdev, 64, virtio_input_handle_sts);
+}
+
+static void virtio_input_device_unrealize(DeviceState *dev, Error **errp)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_GET_CLASS(dev);
+    VirtIODevice *vdev = VIRTIO_DEVICE(dev);
+    Error *local_err = NULL;
+
+    if (vic->unrealize) {
+        vic->unrealize(dev, &local_err);
+        if (local_err) {
+            error_propagate(errp, local_err);
+            return;
+        }
+    }
+    virtio_cleanup(vdev);
+}
+
+static void virtio_input_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
+
+    set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
+    vdc->realize      = virtio_input_device_realize;
+    vdc->unrealize    = virtio_input_device_unrealize;
+    vdc->get_config   = virtio_input_get_config;
+    vdc->set_config   = virtio_input_set_config;
+    vdc->get_features = virtio_input_get_features;
+    vdc->set_status   = virtio_input_set_status;
+    vdc->reset        = virtio_input_reset;
+}
+
+static const TypeInfo virtio_input_info = {
+    .name          = TYPE_VIRTIO_INPUT,
+    .parent        = TYPE_VIRTIO_DEVICE,
+    .instance_size = sizeof(VirtIOInput),
+    .class_size    = sizeof(VirtIOInputClass),
+    .class_init    = virtio_input_class_init,
+    .abstract      = true,
+};
+
+/* ----------------------------------------------------------------- */
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_input_info);
+}
+
+type_init(virtio_register_types)