[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH] Add virtio input device specification.
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] [PATCH] Add virtio input device specification. |
Date: |
Wed, 4 May 2016 14:38:44 +0200 |
Resuming the effort to get the input device specs actually merged.
Support has been added to the linux kernel version 4.1
and to qemu version 2.4.
git branch:
https://www.kraxel.org/cgit/virtio-spec/log/?h=virtio-input
Rendered versions are available here:
https://www.kraxel.org/virtio/virtio-v1.0-cs03-virtio-input.pdf
https://www.kraxel.org/virtio/virtio-v1.0-cs03-virtio-input.html#x1-2800007
Signed-off-by: Gerd Hoffmann <address@hidden>
---
content.tex | 2 +
virtio-input.tex | 124 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 126 insertions(+)
create mode 100644 virtio-input.tex
diff --git a/content.tex b/content.tex
index d989d98..4c0c4c9 100644
--- a/content.tex
+++ b/content.tex
@@ -5641,6 +5641,8 @@ descriptor for the \field{sense_len}, \field{residual},
\field{status_qualifier}, \field{status}, \field{response} and
\field{sense} fields.
+\input{virtio-input.tex}
+
\chapter{Reserved Feature Bits}\label{sec:Reserved Feature Bits}
Currently there are three device-independent feature bits defined:
diff --git a/virtio-input.tex b/virtio-input.tex
new file mode 100644
index 0000000..cdc16ac
--- /dev/null
+++ b/virtio-input.tex
@@ -0,0 +1,124 @@
+\section{Input Device}\label{sec:Device Types / Input Device}
+
+The virtio input device can be used to create virtual human interface
+devices such as keyboards, mice and tablets. It basically sends linux
+input layer events over virtio.
+See
\href{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/input.h}{include/uapi/linux/input.h}
+and
\href{https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/input-event-codes.h}{include/uapi/linux/input-event-codes.h}
+in the linux source tree.
+
+\subsection{Device ID}\label{sec:Device Types / Input Device / Device ID}
+
+18
+
+\subsection{Virtqueues}\label{sec:Device Types / Input Device / Virtqueues}
+
+\begin{description}
+\item[0] eventq
+\item[1] statusq
+\end{description}
+
+\subsection{Feature bits}\label{sec:Device Types / Input Device / Feature bits}
+
+None.
+
+\subsection{Device configuration layout}\label{sec:Device Types / Input Device
/ Device configuration layout}
+
+Device configuration holds all information the guest needs to handle
+the device, most importantly the events which are supported.
+
+\begin{lstlisting}
+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_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;
+};
+
+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;
+ } u;
+};
+\end{lstlisting}
+
+To query a specific piece of information the driver MUST set
+\field{select} and \field{subsel} accordingly, then check \field{size}
+to see and how much information is available. \field{size} can be
+zero if no information is available.
+
+\begin{description}
+
+\item[VIRTIO_INPUT_CFG_ID_NAME]
+\field{subsel} is not used and MUST be zero.
+Returns the name of the device, in \field{u.string}.
+
+Same as EVIOCGNAME ioctl for linux evdev devices.
+
+\item[VIRTIO_INPUT_CFG_ID_SERIAL]
+\field{subsel} is not used and MUST be zero.
+Returns the serial number of the device, in \field{u.string}.
+
+\item[VIRTIO_INPUT_CFG_PROP_BITS]
+\field{subsel} is not used and MUST be zero.
+Returns input properties (INPUT_PROP_*) of the device, in \field{u.bitmap}.
+
+\item[VIRTIO_INPUT_CFG_EV_BITS]
+\field{subsel} specifies the event type (EV_*). If \field{size} is
+non-zero the event type is supported and a bitmap the of supported
+event codes is returned in \field{u.bitmap}.
+
+Same as EVIOCGBIT ioctl.
+
+\item[VIRTIO_INPUT_CFG_ABS_INFO]
+\field{subsel} specifies the absolute axes (ABS_*).
+Informations about the axis will be returned in \field{u.abs}.
+
+Same as EVIOCGABS ioctl.
+
+\end{description}
+
+\subsection{Device Initialization}\label{sec:Device Types / Input Device /
Device Initialization}
+
+\begin{enumerate}
+\item The device is queried for supported event types and codes.
+\item The eventq is populated with receive buffers.
+\end{enumerate}
+
+\subsection{Device Operation}\label{sec:Device Types / Input Device / Device
Operation}
+
+\begin{enumerate}
+\item Input events such as press and release events for keys and
+ buttons and motion events are send from the device to the driver
+ using the eventq.
+\item Status feedback such as keyboard led updates are sent from the
+ driver to the device using the statusq.
+\item Both queues use the same virtio_input_event struct.
+ \field{type}, \field{code} and \field{value} are filled according to
+ the linux input layer (evdev) interface, except that the fields are
+ in little endian byte order whereas the evdev ioctl interface uses
+ native endian.
+\end{enumerate}
+
+\begin{lstlisting}
+struct virtio_input_event {
+ le16 type;
+ le16 code;
+ le32 value;
+};
+\end{lstlisting}
--
1.8.3.1
- [Qemu-devel] [PATCH] Add virtio input device specification.,
Gerd Hoffmann <=