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linux-next/drivers/w1/w1_netlink.h
David Fries 8a0427d192 w1: optional bundling of netlink kernel replies
Applications can submit a set of commands in one packet to the kernel,
and in some cases it is required such as reading the temperature
sensor results.  This adds an option W1_CN_BUNDLE to the flags of
cn_msg to request the kernel to reply in one packet for efficiency.

The cn_msg flags now check for unknown flag values and return an error
if one is seen.  See "Proper handling of unknown flags in system
calls" http://lwn.net/Articles/588444/

This corrects the ack values returned as per the protocol standard,
namely the original ack for status messages and seq + 1 for all others
such as the data returned from a read.

Some of the common variable names have been standardized as follows.
struct cn_msg *cn
struct w1_netlink_msg *msg
struct w1_netlink_cmd *cmd
struct w1_master *dev

When an argument and a function scope variable would collide, add req_
to the argument.

Signed-off-by: David Fries <David@Fries.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-05-27 13:56:21 -07:00

148 lines
4.1 KiB
C

/*
* w1_netlink.h
*
* Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef __W1_NETLINK_H
#define __W1_NETLINK_H
#include <asm/types.h>
#include <linux/connector.h>
#include "w1.h"
/**
* enum w1_cn_msg_flags - bitfield flags for struct cn_msg.flags
*
* @W1_CN_BUNDLE: Request bundling replies into fewer messagse. Be prepared
* to handle multiple struct cn_msg, struct w1_netlink_msg, and
* struct w1_netlink_cmd in one packet.
*/
enum w1_cn_msg_flags {
W1_CN_BUNDLE = 1,
};
/**
* enum w1_netlink_message_types - message type
*
* @W1_SLAVE_ADD: notification that a slave device was added
* @W1_SLAVE_REMOVE: notification that a slave device was removed
* @W1_MASTER_ADD: notification that a new bus master was added
* @W1_MASTER_REMOVE: notification that a bus masterwas removed
* @W1_MASTER_CMD: initiate operations on a specific master
* @W1_SLAVE_CMD: sends reset, selects the slave, then does a read/write/touch
* operation
* @W1_LIST_MASTERS: used to determine the bus master identifiers
*/
enum w1_netlink_message_types {
W1_SLAVE_ADD = 0,
W1_SLAVE_REMOVE,
W1_MASTER_ADD,
W1_MASTER_REMOVE,
W1_MASTER_CMD,
W1_SLAVE_CMD,
W1_LIST_MASTERS,
};
/**
* struct w1_netlink_msg - holds w1 message type, id, and result
*
* @type: one of enum w1_netlink_message_types
* @status: kernel feedback for success 0 or errno failure value
* @len: length of data following w1_netlink_msg
* @id: union holding master bus id (msg.id) and slave device id (id[8]).
* @data: start address of any following data
*
* The base message structure for w1 messages over netlink.
* The netlink connector data sequence is, struct nlmsghdr, struct cn_msg,
* then one or more struct w1_netlink_msg (each with optional data).
*/
struct w1_netlink_msg
{
__u8 type;
__u8 status;
__u16 len;
union {
__u8 id[8];
struct w1_mst {
__u32 id;
__u32 res;
} mst;
} id;
__u8 data[0];
};
/**
* enum w1_commands - commands available for master or slave operations
*
* @W1_CMD_READ: read len bytes
* @W1_CMD_WRITE: write len bytes
* @W1_CMD_SEARCH: initiate a standard search, returns only the slave
* devices found during that search
* @W1_CMD_ALARM_SEARCH: search for devices that are currently alarming
* @W1_CMD_TOUCH: Touches a series of bytes.
* @W1_CMD_RESET: sends a bus reset on the given master
* @W1_CMD_SLAVE_ADD: adds a slave to the given master,
* 8 byte slave id at data[0]
* @W1_CMD_SLAVE_REMOVE: removes a slave to the given master,
* 8 byte slave id at data[0]
* @W1_CMD_LIST_SLAVES: list of slaves registered on this master
* @W1_CMD_MAX: number of available commands
*/
enum w1_commands {
W1_CMD_READ = 0,
W1_CMD_WRITE,
W1_CMD_SEARCH,
W1_CMD_ALARM_SEARCH,
W1_CMD_TOUCH,
W1_CMD_RESET,
W1_CMD_SLAVE_ADD,
W1_CMD_SLAVE_REMOVE,
W1_CMD_LIST_SLAVES,
W1_CMD_MAX
};
/**
* struct w1_netlink_cmd - holds the command and data
*
* @cmd: one of enum w1_commands
* @res: reserved
* @len: length of data following w1_netlink_cmd
* @data: start address of any following data
*
* One or more struct w1_netlink_cmd is placed starting at w1_netlink_msg.data
* each with optional data.
*/
struct w1_netlink_cmd
{
__u8 cmd;
__u8 res;
__u16 len;
__u8 data[0];
};
#ifdef __KERNEL__
void w1_netlink_send(struct w1_master *, struct w1_netlink_msg *);
int w1_init_netlink(void);
void w1_fini_netlink(void);
#endif /* __KERNEL__ */
#endif /* __W1_NETLINK_H */