input: add virtio input driver

We already support Linux event codes, because they are used in the
device tree bindings for e.g. gpio-keys.

Virtio input devices report events using the same codes, so a driver
just has to shovel the codes from virtqueue into the input layer. Do so.

Signed-off-by: Ahmad Fatoum <ahmad@a3f.at>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

4 files changed, 179 insertions, 0 deletions

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 8a1a80ddc8..719f45c975 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -24,6 +24,13 @@ struct virtio_sg {
 	size_t length;
 };
 
+static inline void virtio_sg_init_one(struct virtio_sg *sg,
+				      void *addr, size_t length)
+{
+	sg[0].addr = addr;
+	sg[0].length = length;
+}
+
 struct virtio_config_ops;
 
 /**
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index f33cfdacaa..8160f0952f 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -458,6 +458,68 @@ static inline void virtio_cwrite64(struct virtio_device *vdev,
 		_r;							\
 	})
 
+/*
+ * Nothing virtio-specific about these, but let's worry about generalizing
+ * these later.
+ */
+#define virtio_le_to_cpu(x) \
+	_Generic((x), \
+		__u8: (u8)(x), \
+		 __le16: (u16)le16_to_cpu(x), \
+		 __le32: (u32)le32_to_cpu(x), \
+		 __le64: (u64)le64_to_cpu(x) \
+		)
+
+#define virtio_cpu_to_le(x, m) \
+	_Generic((m), \
+		 __u8: (x), \
+		 __le16: cpu_to_le16(x), \
+		 __le32: cpu_to_le32(x), \
+		 __le64: cpu_to_le64(x) \
+		)
+
+/* LE (e.g. modern) Config space accessors. */
+#define virtio_cread_le(vdev, structname, member, ptr)			\
+	do {								\
+		typeof(((structname*)0)->member) virtio_cread_v;	\
+									\
+		/* Sanity check: must match the member's type */	\
+		typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \
+									\
+		switch (sizeof(virtio_cread_v)) {			\
+		case 1:							\
+		case 2:							\
+		case 4:							\
+			vdev->config->get_config((vdev),		\
+					  offsetof(structname, member), \
+					  &virtio_cread_v,		\
+					  sizeof(virtio_cread_v));	\
+			break;						\
+		default:						\
+			__virtio_cread_many((vdev), 			\
+					  offsetof(structname, member), \
+					  &virtio_cread_v,		\
+					  1,				\
+					  sizeof(virtio_cread_v));	\
+			break;						\
+		}							\
+		*(ptr) = virtio_le_to_cpu(virtio_cread_v);		\
+	} while(0)
+
+#define virtio_cwrite_le(vdev, structname, member, ptr)			\
+	do {								\
+		typeof(((structname*)0)->member) virtio_cwrite_v =	\
+			virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \
+									\
+		/* Sanity check: must match the member's type */	\
+		typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \
+									\
+		vdev->config->set_config((vdev), offsetof(structname, member),	\
+				  &virtio_cwrite_v,			\
+				  sizeof(virtio_cwrite_v));		\
+	} while(0)
+
+
 #ifdef CONFIG_ARCH_HAS_RESTRICTED_VIRTIO_MEMORY_ACCESS
 int arch_has_restricted_virtio_memory_access(void);
 #else
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index c349af90ce..bdef47b0fa 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -181,6 +181,40 @@ int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
 		  unsigned int out_sgs, unsigned int in_sgs);
 
 /**
+ * virtqueue_add_outbuf - expose output buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg readable by other side
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_outbuf(struct virtqueue *vq,
+                                      struct virtio_sg *sg, unsigned int num)
+{
+	return virtqueue_add(vq, &sg, num, 0);
+}
+
+/**
+ * virtqueue_add_inbuf - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_inbuf(struct virtqueue *vq,
+                                     struct virtio_sg *sg, unsigned int num)
+{
+	return virtqueue_add(vq, &sg, 0, num);
+}
+
+/**
  * virtqueue_kick - update after add_buf
  *
  * @vq:		the struct virtqueue
diff --git a/include/uapi/linux/virtio_input.h b/include/uapi/linux/virtio_input.h
new file mode 100644
index 0000000000..52084b1fb9
--- /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 {
+	__le32 min;
+	__le32 max;
+	__le32 fuzz;
+	__le32 flat;
+	__le32 res;
+};
+
+struct virtio_input_devids {
+	__le16 bustype;
+	__le16 vendor;
+	__le16 product;
+	__le16 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 */