Re: [PATCH v2] Add virtio-input driver.

Hi Gerd,

On Fri, Mar 20, 2015 at 01:39:29PM +0100, Gerd Hoffmann wrote:

Since serial is uniq and uniq is already exposed in sysfs by input core
please remove this attribute (and the rest of attribute group handling).

+
+static struct attribute *dev_attrs[] = {
+	&dev_attr_serial.attr,
+	NULL
+};
+
+static umode_t dev_attrs_are_visible(struct kobject *kobj,
+				     struct attribute *a, int n)
+{
+	struct device *dev = container_of(kobj, struct device, kobj);
+	struct input_dev *idev = to_input_dev(dev);
+	struct virtio_input *vi = input_get_drvdata(idev);
+
+	if (a == &dev_attr_serial.attr && !strlen(vi->serial))
+		return 0;
+
+	return a->mode;
+}
+
+static struct attribute_group dev_attr_grp = {
+	.attrs =	dev_attrs,
+	.is_visible =	dev_attrs_are_visible,
+};
+
+static const struct attribute_group *dev_attr_groups[] = {
+	&dev_attr_grp,
+	NULL
+};
+
+static void virtinput_queue_evtbuf(struct virtio_input *vi,
+				   struct virtio_input_event *evtbuf)
+{
+	struct scatterlist sg[1];
+
+	sg_init_one(sg, evtbuf, sizeof(*evtbuf));
+	virtqueue_add_inbuf(vi->evt, sg, 1, evtbuf, GFP_ATOMIC);
+}
+
+static void virtinput_recv_events(struct virtqueue *vq)
+{
+	struct virtio_input *vi = vq->vdev->priv;
+	struct virtio_input_event *event;
+	unsigned int len;
+
+	mutex_lock(&vi->lock);
+	while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) {
+		input_event(vi->idev,
+			    le16_to_cpu(event->type),
+			    le16_to_cpu(event->code),
+			    le32_to_cpu(event->value));
+		virtinput_queue_evtbuf(vi, event);
+	}
+	virtqueue_kick(vq);
+	mutex_unlock(&vi->lock);
+}
+
+static int virtinput_send_status(struct virtio_input *vi,
+				 u16 type, u16 code, s32 value)
+{
+	struct virtio_input_event *stsbuf;
+	struct scatterlist sg[1];
+	int rc;
+
+	stsbuf = kzalloc(sizeof(*stsbuf), GFP_ATOMIC);
+	if (!stsbuf)
+		return -ENOMEM;
+
+	stsbuf->type  = cpu_to_le16(type);
+	stsbuf->code  = cpu_to_le16(code);
+	stsbuf->value = cpu_to_le32(value);
+	sg_init_one(sg, stsbuf, sizeof(*stsbuf));
+
+	mutex_lock(&vi->lock);
+	rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
+	virtqueue_kick(vi->sts);
+	mutex_unlock(&vi->lock);
+
+	if (rc != 0)
+		kfree(stsbuf);
+	return rc;
+}
+
+static void virtinput_recv_status(struct virtqueue *vq)
+{
+	struct virtio_input *vi = vq->vdev->priv;
+	struct virtio_input_event *stsbuf;
+	unsigned int len;
+
+	mutex_lock(&vi->lock);
+	while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL)
+		kfree(stsbuf);
+	mutex_unlock(&vi->lock);
+}
+
+static int virtinput_status(struct input_dev *idev, unsigned int type,
+			    unsigned int code, int value)
+{
+	struct virtio_input *vi = input_get_drvdata(idev);
+
+	return virtinput_send_status(vi, type, code, value);
+}
+
+static size_t virtinput_cfg_select(struct virtio_input *vi,
+				   u8 select, u8 subsel)
+{
+	u8 size;
+
+	virtio_cwrite(vi->vdev, struct virtio_input_config, select, &select);
+	virtio_cwrite(vi->vdev, struct virtio_input_config, subsel, &subsel);
+	virtio_cread(vi->vdev, struct virtio_input_config, size, &size);
+	return size;
+}
+
+static void virtinput_cfg_bits(struct virtio_input *vi, int select, int subsel,
+			       unsigned long *bits, unsigned int bitcount)
+{
+	unsigned int bit;
+	size_t bytes;
+	u8 cfg = 0;
+
+	bytes = virtinput_cfg_select(vi, select, subsel);
+	if (!bytes)
+		return;
+	if (bitcount > bytes*8)
+		bitcount = bytes*8;
+	if (select == VIRTIO_INPUT_CFG_EV_BITS)
+		set_bit(subsel, vi->idev->evbit);
+	for (bit = 0; bit < bitcount; bit++) {
+		if ((bit % 8) == 0)
+			virtio_cread(vi->vdev, struct virtio_input_config,
+				     u.bitmap[bit / 8], &cfg);
+		if (cfg & (1 << (bit % 8)))
+			set_bit(bit, bits);
+	}
+}
+
+static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
+{
+	u32 mi, ma, fu, fl;
+
+	virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ABS_INFO, abs);
+	virtio_cread(vi->vdev, struct virtio_input_config, u.abs.min, &mi);
+	virtio_cread(vi->vdev, struct virtio_input_config, u.abs.max, &ma);
+	virtio_cread(vi->vdev, struct virtio_input_config, u.abs.fuzz, &fu);
+	virtio_cread(vi->vdev, struct virtio_input_config, u.abs.flat, &fl);
+	input_set_abs_params(vi->idev, abs, mi, ma, fu, fl);

What about setting resolution as David suggested?

+}
+
+static int virtinput_init_vqs(struct virtio_input *vi)
+{
+	struct virtqueue *vqs[2];
+	vq_callback_t *cbs[] = { virtinput_recv_events,
+				 virtinput_recv_status };
+	static const char * names[] = { "events", "status" };
+	int i, err, size;
+
+	err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names);
+	if (err)
+		return err;
+	vi->evt = vqs[0];
+	vi->sts = vqs[1];
+
+	size = virtqueue_get_vring_size(vi->evt);
+	if (size > ARRAY_SIZE(vi->evts))
+		size = ARRAY_SIZE(vi->evts);
+	for (i = 0; i < size; i++)
+		virtinput_queue_evtbuf(vi, &vi->evts[i]);
+	virtqueue_kick(vi->evt);
+
+	return 0;
+}
+
+static int virtinput_probe(struct virtio_device *vdev)
+{
+	struct virtio_input *vi;
+	size_t size;
+	int abs, err;
+
+	vi = kzalloc(sizeof(*vi), GFP_KERNEL);
+	if (!vi)
+		return -ENOMEM;
+
+	vdev->priv = vi;
+	vi->vdev = vdev;
+	mutex_init(&vi->lock);
+
+	err = virtinput_init_vqs(vi);
+	if (err)
+		goto err_init_vq;
+
+	vi->idev = input_allocate_device();
+	if (!vi->idev) {
+		err = -ENOMEM;
+		goto err_input_alloc;
+	}
+	input_set_drvdata(vi->idev, vi);
+
+	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_NAME, 0);
+	virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u),
+			   vi->name, min(size, sizeof(vi->name)));
+	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_SERIAL, 0);
+	virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config, u),
+			   vi->serial, min(size, sizeof(vi->serial)));
+	snprintf(vi->phys, sizeof(vi->phys),
+		 "virtio%d/input0", vdev->index);
+	vi->idev->name = vi->name;
+	vi->idev->phys = vi->phys;
+	vi->idev->uniq = vi->serial;
+
+	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_ID_DEVIDS, 0);
+	if (size >= 8) {
+		virtio_cread(vi->vdev, struct virtio_input_config,
+			     u.ids.bustype, &vi->idev->id.bustype);
+		virtio_cread(vi->vdev, struct virtio_input_config,
+			     u.ids.vendor, &vi->idev->id.vendor);
+		virtio_cread(vi->vdev, struct virtio_input_config,
+			     u.ids.product, &vi->idev->id.product);
+		virtio_cread(vi->vdev, struct virtio_input_config,
+			     u.ids.version, &vi->idev->id.version);
+	} else {
+		vi->idev->id.bustype = BUS_VIRTUAL;
+	}
+
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_PROP_BITS, 0,
+			   vi->idev->propbit, INPUT_PROP_CNT);
+	size = virtinput_cfg_select(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REP);
+	if (size)
+		set_bit(EV_REP, vi->idev->evbit);
+
+	vi->idev->dev.parent = &vdev->dev;
+	vi->idev->dev.groups = dev_attr_groups;
+	vi->idev->event = virtinput_status;
+
+	/* device -> kernel */
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_KEY,
+			   vi->idev->keybit, KEY_CNT);
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_REL,
+			   vi->idev->relbit, REL_CNT);
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_ABS,
+			   vi->idev->absbit, ABS_CNT);
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_MSC,
+			   vi->idev->mscbit, MSC_CNT);
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SW,
+			   vi->idev->swbit,  SW_CNT);
+
+	/* kernel -> device */
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_LED,
+			   vi->idev->ledbit, LED_CNT);
+	virtinput_cfg_bits(vi, VIRTIO_INPUT_CFG_EV_BITS, EV_SND,
+			   vi->idev->sndbit, SND_CNT);
+
+	if (test_bit(EV_ABS, vi->idev->evbit)) {
+		for (abs = 0; abs < ABS_CNT; abs++) {
+			if (!test_bit(abs, vi->idev->absbit))
+				continue;
+			virtinput_cfg_abs(vi, abs);
+		}
+	}
+	virtio_device_ready(vdev);
+
+	err = input_register_device(vi->idev);
+	if (err)
+		goto err_input_register;
+
+	return 0;
+
+err_input_register:
+	input_free_device(vi->idev);
+err_input_alloc:
+	vdev->config->del_vqs(vdev);
+err_init_vq:
+	kfree(vi);
+	return err;
+}
+
+static void virtinput_remove(struct virtio_device *vdev)
+{
+	struct virtio_input *vi = vdev->priv;
+
+	input_unregister_device(vi->idev);
+	input_free_device(vi->idev);

Freeing input devices after unregistering is verboten.

Thanks.

-- 
Dmitry