Add virtio-input driver.

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@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

7 files changed, 479 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 0e1abe8cc684..585e6cdd9186 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10435,6 +10435,12 @@ S:	Maintained
 F:      drivers/vhost/
 F:      include/uapi/linux/vhost.h
 
+VIRTIO INPUT DRIVER
+M:      Gerd Hoffmann <kraxel@redhat.com>
+S:      Maintained
+F:      drivers/virtio/virtio_input.c
+F:      include/uapi/linux/virtio_input.h
+
 VIA RHINE NETWORK DRIVER
 M:      Roger Luethi <rl@hellgate.ch>
 S:      Maintained
diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index b546da5d8ea3..cab9f3f63a38 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 d85565b8ea46..41e30e3dc842 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 000000000000..60e2a1677563
--- /dev/null
+++ b/drivers/virtio/virtio_input.c
@@ -0,0 +1,384 @@
+#include <linux/module.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.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];
+        spinlock_t                 lock;
+        bool                       ready;
+};
+
+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 long flags;
+        unsigned int len;
+
+        spin_lock_irqsave(&vi->lock, flags);
+        if (vi->ready) {
+                while ((event = virtqueue_get_buf(vi->evt, &len)) != NULL) {
+                        spin_unlock_irqrestore(&vi->lock, flags);
+                        input_event(vi->idev,
+                                    le16_to_cpu(event->type),
+                                    le16_to_cpu(event->code),
+                                    le32_to_cpu(event->value));
+                        spin_lock_irqsave(&vi->lock, flags);
+                        virtinput_queue_evtbuf(vi, event);
+                }
+                virtqueue_kick(vq);
+        }
+        spin_unlock_irqrestore(&vi->lock, flags);
+}
+
+/*
+ * On error we are losing the status update, which isn't critical as
+ * this is typically used for stuff like keyboard leds.
+ */
+static int virtinput_send_status(struct virtio_input *vi,
+                                 u16 type, u16 code, s32 value)
+{
+        struct virtio_input_event *stsbuf;
+        struct scatterlist sg[1];
+        unsigned long flags;
+        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));
+
+        spin_lock_irqsave(&vi->lock, flags);
+        if (vi->ready) {
+                rc = virtqueue_add_outbuf(vi->sts, sg, 1, stsbuf, GFP_ATOMIC);
+                virtqueue_kick(vi->sts);
+        } else {
+                rc = -ENODEV;
+        }
+        spin_unlock_irqrestore(&vi->lock, flags);
+
+        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 long flags;
+        unsigned int len;
+
+        spin_lock_irqsave(&vi->lock, flags);
+        while ((stsbuf = virtqueue_get_buf(vi->sts, &len)) != NULL)
+                kfree(stsbuf);
+        spin_unlock_irqrestore(&vi->lock, flags);
+}
+
+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 u8 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;
+        u8 *virtio_bits;
+        u8 bytes;
+
+        bytes = virtinput_cfg_select(vi, select, subsel);
+        if (!bytes)
+                return;
+        if (bitcount > bytes * 8)
+                bitcount = bytes * 8;
+
+        /*
+         * Bitmap in virtio config space is a simple stream of bytes,
+         * with the first byte carrying bits 0-7, second bits 8-15 and
+         * so on.
+         */
+        virtio_bits = kzalloc(bytes, GFP_KERNEL);
+        if (!virtio_bits)
+                return;
+        virtio_cread_bytes(vi->vdev, offsetof(struct virtio_input_config,
+                                              u.bitmap),
+                           virtio_bits, bytes);
+        for (bit = 0; bit < bitcount; bit++) {
+                if (virtio_bits[bit / 8] & (1 << (bit % 8)))
+                        __set_bit(bit, bits);
+        }
+        kfree(virtio_bits);
+
+        if (select == VIRTIO_INPUT_CFG_EV_BITS)
+                __set_bit(subsel, vi->idev->evbit);
+}
+
+static void virtinput_cfg_abs(struct virtio_input *vi, int abs)
+{
+        u32 mi, ma, re, 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.res, &re);
+        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);
+        input_abs_set_res(vi->idev, abs, re);
+}
+
+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 err;
+
+        err = vi->vdev->config->find_vqs(vi->vdev, 2, vqs, cbs, names);
+        if (err)
+                return err;
+        vi->evt = vqs[0];
+        vi->sts = vqs[1];
+
+        return 0;
+}
+
+static void virtinput_fill_evt(struct virtio_input *vi)
+{
+        unsigned long flags;
+        int i, size;
+
+        spin_lock_irqsave(&vi->lock, flags);
+        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);
+        spin_unlock_irqrestore(&vi->lock, flags);
+}
+
+static int virtinput_probe(struct virtio_device *vdev)
+{
+        struct virtio_input *vi;
+        unsigned long flags;
+        size_t size;
+        int abs, err;
+
+        if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
+                return -ENODEV;
+
+        vi = kzalloc(sizeof(*vi), GFP_KERNEL);
+        if (!vi)
+                return -ENOMEM;
+
+        vdev->priv = vi;
+        vi->vdev = vdev;
+        spin_lock_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.string),
+                           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.string),
+                           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 >= sizeof(struct virtio_input_devids)) {
+                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->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);
+        vi->ready = true;
+        err = input_register_device(vi->idev);
+        if (err)
+                goto err_input_register;
+
+        virtinput_fill_evt(vi);
+        return 0;
+
+err_input_register:
+        spin_lock_irqsave(&vi->lock, flags);
+        vi->ready = false;
+        spin_unlock_irqrestore(&vi->lock, flags);
+        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;
+        unsigned long flags;
+
+        spin_lock_irqsave(&vi->lock, flags);
+        vi->ready = false;
+        spin_unlock_irqrestore(&vi->lock, flags);
+
+        input_unregister_device(vi->idev);
+        vdev->config->del_vqs(vdev);
+        kfree(vi);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int virtinput_freeze(struct virtio_device *vdev)
+{
+        struct virtio_input *vi = vdev->priv;
+        unsigned long flags;
+
+        spin_lock_irqsave(&vi->lock, flags);
+        vi->ready = false;
+        spin_unlock_irqrestore(&vi->lock, flags);
+
+        vdev->config->del_vqs(vdev);
+        return 0;
+}
+
+static int virtinput_restore(struct virtio_device *vdev)
+{
+        struct virtio_input *vi = vdev->priv;
+        int err;
+
+        err = virtinput_init_vqs(vi);
+        if (err)
+                return err;
+
+        virtio_device_ready(vdev);
+        vi->ready = true;
+        virtinput_fill_evt(vi);
+        return 0;
+}
+#endif
+
+static unsigned int features[] = {
+        /* none */
+};
+static struct virtio_device_id id_table[] = {
+        { VIRTIO_ID_INPUT, VIRTIO_DEV_ANY_ID },
+        { 0 },
+};
+
+static struct virtio_driver virtio_input_driver = {
+        .driver.name         = KBUILD_MODNAME,
+        .driver.owner        = THIS_MODULE,
+        .feature_table       = features,
+        .feature_table_size  = ARRAY_SIZE(features),
+        .id_table            = id_table,
+        .probe               = virtinput_probe,
+        .remove              = virtinput_remove,
+#ifdef CONFIG_PM_SLEEP
+        .freeze              = virtinput_freeze,
+        .restore             = virtinput_restore,
+#endif
+};
+
+module_virtio_driver(virtio_input_driver);
+MODULE_DEVICE_TABLE(virtio, id_table);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Virtio input device driver");
+MODULE_AUTHOR("Gerd Hoffmann <kraxel@redhat.com>");
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 68ceb97c458c..04b829e9ac46 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -430,6 +430,7 @@ header-y += virtio_blk.h
 header-y += virtio_config.h
 header-y += virtio_console.h
 header-y += virtio_ids.h
+header-y += virtio_input.h
 header-y += virtio_net.h
 header-y += virtio_pci.h
 header-y += virtio_ring.h
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
index 284fc3a05f7b..5f60aa4be50a 100644
--- a/include/uapi/linux/virtio_ids.h
+++ b/include/uapi/linux/virtio_ids.h
@@ -39,5 +39,6 @@
 #define VIRTIO_ID_9P            9 /* 9p virtio console */
 #define VIRTIO_ID_RPROC_SERIAL 11 /* virtio remoteproc serial link */
 #define VIRTIO_ID_CAIF         12 /* Virtio caif */
+#define VIRTIO_ID_INPUT        18 /* virtio input */
 
 #endif /* _LINUX_VIRTIO_IDS_H */
diff --git a/include/uapi/linux/virtio_input.h b/include/uapi/linux/virtio_input.h
new file mode 100644
index 000000000000..a7fe5c8fb135
--- /dev/null
+++ b/include/uapi/linux/virtio_input.h
@@ -0,0 +1,76 @@
+#ifndef _LINUX_VIRTIO_INPUT_H
+#define _LINUX_VIRTIO_INPUT_H
+/* This header is BSD licensed so anyone can use the definitions to implement
+ * compatible drivers/servers.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of IBM nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL IBM OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE. */
+
+#include <linux/types.h>
+
+enum virtio_input_config_select {
+        VIRTIO_INPUT_CFG_UNSET      = 0x00,
+        VIRTIO_INPUT_CFG_ID_NAME    = 0x01,
+        VIRTIO_INPUT_CFG_ID_SERIAL  = 0x02,
+        VIRTIO_INPUT_CFG_ID_DEVIDS  = 0x03,
+        VIRTIO_INPUT_CFG_PROP_BITS  = 0x10,
+        VIRTIO_INPUT_CFG_EV_BITS    = 0x11,
+        VIRTIO_INPUT_CFG_ABS_INFO   = 0x12,
+};
+
+struct virtio_input_absinfo {
+        __u32 min;
+        __u32 max;
+        __u32 fuzz;
+        __u32 flat;
+        __u32 res;
+};
+
+struct virtio_input_devids {
+        __u16 bustype;
+        __u16 vendor;
+        __u16 product;
+        __u16 version;
+};
+
+struct virtio_input_config {
+        __u8    select;
+        __u8    subsel;
+        __u8    size;
+        __u8    reserved[5];
+        union {
+                char string[128];
+                __u8 bitmap[128];
+                struct virtio_input_absinfo abs;
+                struct virtio_input_devids ids;
+        } u;
+};
+
+struct virtio_input_event {
+        __le16 type;
+        __le16 code;
+        __le32 value;
+};
+
+#endif /* _LINUX_VIRTIO_INPUT_H */