serial: add basic VirtIO console driver

With this driver enabled, -device virtio-serial-device can now be passed
to Qemu for barebox to detect a VirtIO console device. If barebox is
passed as argument to the Qemu -kernel option, no device tree changes are
necessary.

Example:

  $ qemu-system-arm -m 256M -M virt -nographic             \
  	-kernel build/images/barebox-dt-2nd.img            \
  	-device virtio-serial-device                       \
  	-chardev socket,path=/tmp/foo,server,nowait,id=foo \
  	-device virtconsole,chardev=foo,name=console.foo

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

1 files changed, 78 insertions, 0 deletions

diff --git a/include/uapi/linux/virtio_console.h b/include/uapi/linux/virtio_console.h
new file mode 100644
index 0000000000..7e6ec2ff05
--- /dev/null
+++ b/include/uapi/linux/virtio_console.h
@@ -0,0 +1,78 @@
+/*
+ * This header, excluding the #ifdef __KERNEL__ part, 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.
+ *
+ * Copyright (C) Red Hat, Inc., 2009, 2010, 2011
+ * Copyright (C) Amit Shah <amit.shah@redhat.com>, 2009, 2010, 2011
+ */
+#ifndef _UAPI_LINUX_VIRTIO_CONSOLE_H
+#define _UAPI_LINUX_VIRTIO_CONSOLE_H
+#include <linux/types.h>
+#include <linux/virtio_types.h>
+#include <linux/virtio_ids.h>
+#include <linux/virtio_config.h>
+
+/* Feature bits */
+#define VIRTIO_CONSOLE_F_SIZE	0	/* Does host provide console size? */
+#define VIRTIO_CONSOLE_F_MULTIPORT 1	/* Does host provide multiple ports? */
+#define VIRTIO_CONSOLE_F_EMERG_WRITE 2 /* Does host support emergency write? */
+
+#define VIRTIO_CONSOLE_BAD_ID		(~(__u32)0)
+
+struct virtio_console_config {
+	/* colums of the screens */
+	__virtio16 cols;
+	/* rows of the screens */
+	__virtio16 rows;
+	/* max. number of ports this device can hold */
+	__virtio32 max_nr_ports;
+	/* emergency write register */
+	__virtio32 emerg_wr;
+} __attribute__((packed));
+
+/*
+ * A message that's passed between the Host and the Guest for a
+ * particular port.
+ */
+struct virtio_console_control {
+	__virtio32 id;		/* Port number */
+	__virtio16 event;	/* The kind of control event (see below) */
+	__virtio16 value;	/* Extra information for the key */
+};
+
+/* Some events for control messages */
+#define VIRTIO_CONSOLE_DEVICE_READY	0
+#define VIRTIO_CONSOLE_PORT_ADD		1
+#define VIRTIO_CONSOLE_PORT_REMOVE	2
+#define VIRTIO_CONSOLE_PORT_READY	3
+#define VIRTIO_CONSOLE_CONSOLE_PORT	4
+#define VIRTIO_CONSOLE_RESIZE		5
+#define VIRTIO_CONSOLE_PORT_OPEN	6
+#define VIRTIO_CONSOLE_PORT_NAME	7
+
+
+#endif /* _UAPI_LINUX_VIRTIO_CONSOLE_H */