Re: [PATCH 1/1] Add virtio-input driver.
From: Dmitry Torokhov
Date: Thu Mar 19 2015 - 12:27:18 EST
On Thu, Mar 19, 2015 at 01:29:49PM +0100, David Herrmann wrote:
> Hi
>
> (CC: Dmitry)
>
> On Thu, Mar 19, 2015 at 10:13 AM, Gerd Hoffmann <kraxel@xxxxxxxxxx> wrote:
> > virtio-input is basically evdev-events-over-virtio, so this driver isn't
> > much more than reading configuration from config space and forwarding
> > incoming events to the linux input layer.
> >
> > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
> > ---
> > drivers/virtio/Kconfig | 10 ++
> > drivers/virtio/Makefile | 1 +
> > drivers/virtio/virtio_input.c | 313 ++++++++++++++++++++++++++++++++++++++
> > include/uapi/linux/virtio_ids.h | 1 +
> > include/uapi/linux/virtio_input.h | 65 ++++++++
> > 5 files changed, 390 insertions(+)
> > create mode 100644 drivers/virtio/virtio_input.c
> > create mode 100644 include/uapi/linux/virtio_input.h
> >
> > diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
> > index b546da5..cab9f3f 100644
> > --- a/drivers/virtio/Kconfig
> > +++ b/drivers/virtio/Kconfig
> > @@ -48,6 +48,16 @@ config VIRTIO_BALLOON
> >
> > If unsure, say M.
> >
> > +config VIRTIO_INPUT
> > + tristate "Virtio input driver"
> > + depends on VIRTIO
> > + depends on INPUT
> > + ---help---
> > + This driver supports virtio input devices such as
> > + keyboards, mice and tablets.
> > +
> > + If unsure, say M.
> > +
> > config VIRTIO_MMIO
> > tristate "Platform bus driver for memory mapped virtio devices"
> > depends on HAS_IOMEM
> > diff --git a/drivers/virtio/Makefile b/drivers/virtio/Makefile
> > index d85565b..41e30e3 100644
> > --- a/drivers/virtio/Makefile
> > +++ b/drivers/virtio/Makefile
> > @@ -4,3 +4,4 @@ obj-$(CONFIG_VIRTIO_PCI) += virtio_pci.o
> > virtio_pci-y := virtio_pci_modern.o virtio_pci_common.o
> > virtio_pci-$(CONFIG_VIRTIO_PCI_LEGACY) += virtio_pci_legacy.o
> > obj-$(CONFIG_VIRTIO_BALLOON) += virtio_balloon.o
> > +obj-$(CONFIG_VIRTIO_INPUT) += virtio_input.o
> > diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c
> > new file mode 100644
> > index 0000000..2d425cf
> > --- /dev/null
> > +++ b/drivers/virtio/virtio_input.c
> > @@ -0,0 +1,313 @@
> > +#include <linux/module.h>
> > +#include <linux/virtio.h>
> > +#include <linux/input.h>
> > +
> > +#include <uapi/linux/virtio_ids.h>
> > +#include <uapi/linux/virtio_input.h>
> > +
> > +struct virtio_input {
> > + struct virtio_device *vdev;
> > + struct input_dev *idev;
> > + char name[64];
> > + char serial[64];
> > + char phys[64];
> > + struct virtqueue *evt, *sts;
> > + struct virtio_input_event evts[64];
> > +};
> > +
> > +static ssize_t serial_show(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + struct input_dev *idev = to_input_dev(dev);
> > + struct virtio_input *vi = input_get_drvdata(idev);
> > + return sprintf(buf, "%s\n", vi->serial);
> > +}
> > +static DEVICE_ATTR_RO(serial);
What is serial? Serial number?
> > +
> > +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;
> > +
> > + 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);
> > +}
> > +
> > +static int virtinput_send_status(struct virtio_input *vi,
> > + u16 type, u16 code, s32 value)
> > +{
> > + struct virtio_input_event *stsbuf;
> > + struct scatterlist sg[1];
> > +
> > + 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));
> > + virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
> > + virtqueue_kick(vi->sts);
>
> GFP_ATOMIC, eww. But everyone does that for input_event() callbacks..
> we should fix that for user-space input one day.
>
> > + return 0;
> > +}
> > +
> > +static void virtinput_recv_status(struct virtqueue *vq)
> > +{
> > + struct virtio_input *vi = vq->vdev->priv;
> > + struct virtio_input_event *stsbuf;
> > + unsigned int len;
> > +
> > + while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL)
> > + kfree(stsbuf);
> > + virtqueue_kick(vq);
> > +}
> > +
> > +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 size, mi, ma, fu, fl;
> > +
> > + size = 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);
>
> abs.resolution is missing. Please add it, we really also need to add
> it to uinput one day.
>
> > + input_set_abs_params(vi->idev, abs,
> > + le32_to_cpu(mi), le32_to_cpu(ma),
> > + le32_to_cpu(fu), le32_to_cpu(fl));
> > +}
> > +
> > +static int virtinput_init_vqs(struct virtio_input *vi)
> > +{
> > + struct virtqueue *vqs[2];
> > + vq_callback_t *cbs[] = { virtinput_recv_events,
> > + virtinput_recv_status };
> > + 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]);
> > +
> > + 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) {
> > + err = -ENOMEM;
> > + goto out1;
> > + }
> > + vdev->priv = vi;
> > + vi->vdev = vdev;
> > +
> > + err = virtinput_init_vqs(vi);
> > + if (err)
> > + goto out2;
> > +
> > + vi->idev = input_allocate_device();
> > + if (!vi->idev) {
> > + err = -ENOMEM;
> > + goto out3;
> > + }
> > + 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);
> > +
> > + 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->name = vi->name;
> > + vi->idev->phys = vi->phys;
>
> Can you set vi->idev->uniq to the virtio-bus path?
No, uniq can't be phys as phys is unique within the system while uniq is
like serial number or UUID and should never repeat.
Thanks.
--
Dmitry
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