[RFC 06/16] bus1: add the user-space API

[David Rheinsberg <david@readahead.eu>]

Add the user-space API of bus1. Everything is contained in linux/bus1.h
for now, and exposed via a character-device. This allows hotloading of
the module during development.

In the future, a syscall based API, as demanded previously, can be added
as well. The ioctls on the character device are designed with this in
mind, and can be easily translated into syscalls, as is already
documented in the man-page.

The API has no inline documentation. Instead, documentation is provided
in ./Documentation/bus1/bus1.7.rst.

Signed-off-by: David Rheinsberg <david@readahead.eu>
---
 include/uapi/linux/bus1.h | 77 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)

diff --git a/include/uapi/linux/bus1.h b/include/uapi/linux/bus1.h
index 4297e7a00ab9..b4317675475e 100644
--- a/include/uapi/linux/bus1.h
+++ b/include/uapi/linux/bus1.h
@@ -2,4 +2,81 @@
 #ifndef _UAPI_LINUX_BUS1_H
 #define _UAPI_LINUX_BUS1_H
 
+#include <linux/ioctl.h>
+#include <linux/types.h>
+
+#define BUS1_IOCTL_MAGIC			(0x97)
+#define BUS1_INVALID				((__u64)-1)
+#define BUS1_MANAGED				((__u64)0x1)
+
+#define BUS1_FROM_PTR(_v) ((__u64)(void *)(_v))
+#define BUS1_TO_PTR(_v) ((void *)(__u64)(_v))
+
+#define BUS1_TRANSFER_FLAG_CREATE		(((__u64)1) << 0)
+
+struct bus1_transfer {
+	__u64 flags;
+	__u64 id;
+} __attribute__((__aligned__(8)));
+
+struct bus1_metadata {
+	__u64 flags;
+	__u64 id;
+	__u64 account;
+} __attribute__((__aligned__(8)));
+
+enum bus1_message_type: __u64 {
+	BUS1_MESSAGE_TYPE_USER			= 0,
+	BUS1_MESSAGE_TYPE_NODE_RELEASE		= 1,
+	BUS1_MESSAGE_TYPE_HANDLE_RELEASE	= 2,
+	_BUS1_MESSAGE_TYPE_N,
+};
+
+struct bus1_message {
+	__u64 flags;
+	__u64 type;
+	__u64 n_transfers;
+	__u64 ptr_transfers;
+	__u64 n_data;
+	__u64 n_data_vecs;
+	__u64 ptr_data_vecs;
+} __attribute__((__aligned__(8)));
+
+struct bus1_cmd_transfer {
+	__u64 flags;
+	__u64 to;
+	__u64 n_transfers;
+	__u64 ptr_src;
+	__u64 ptr_dst;
+} __attribute__((__aligned__(8)));
+
+struct bus1_cmd_release {
+	__u64 flags;
+	__u64 n_ids;
+	__u64 ptr_ids;
+} __attribute__((__aligned__(8)));
+
+struct bus1_cmd_send {
+	__u64 flags;
+	__u64 n_destinations;
+	__u64 ptr_destinations;
+	__u64 ptr_errors;
+	__u64 ptr_message;
+} __attribute__((__aligned__(8)));
+
+struct bus1_cmd_recv {
+	__u64 flags;
+	__u64 ptr_metadata;
+	__u64 ptr_message;
+} __attribute__((__aligned__(8)));
+
+#define BUS1_CMD_TRANSFER \
+	(_IOWR(BUS1_IOCTL_MAGIC, 0x00, struct bus1_cmd_transfer))
+#define BUS1_CMD_RELEASE \
+	(_IOWR(BUS1_IOCTL_MAGIC, 0x01, struct bus1_cmd_release))
+#define BUS1_CMD_SEND \
+	(_IOWR(BUS1_IOCTL_MAGIC, 0x02, struct bus1_cmd_send))
+#define BUS1_CMD_RECV \
+	(_IOWR(BUS1_IOCTL_MAGIC, 0x03, struct bus1_cmd_recv))
+
 #endif /* _UAPI_LINUX_BUS1_H */
-- 
2.53.0