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The tty lock is strictly for serializing tty lifetime events (open/close/hangup), and not for line discipline serialization. The tty core already provides serialization of concurrent writes to the same tty, and line discipline lifetime management (by ldisc references), so pinning the tty via tty_lock() is unnecessary and counter-productive; remove tty lock use. However, the line discipline is responsible for serializing reads (if required by the line discipline); add read_lock mutex to serialize calls of r3964_read(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
175 lines
4.1 KiB
C
175 lines
4.1 KiB
C
/* r3964 linediscipline for linux
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*
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* -----------------------------------------------------------
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* Copyright by
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* Philips Automation Projects
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* Kassel (Germany)
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* -----------------------------------------------------------
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* This software may be used and distributed according to the terms of
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* the GNU General Public License, incorporated herein by reference.
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*
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* Author:
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* L. Haag
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*
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* $Log: r3964.h,v $
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* Revision 1.4 2005/12/21 19:54:24 Kurt Huwig <kurt huwig de>
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* Fixed HZ usage on 2.6 kernels
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* Removed unnecessary include
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*
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* Revision 1.3 2001/03/18 13:02:24 dwmw2
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* Fix timer usage, use spinlocks properly.
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*
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* Revision 1.2 2001/03/18 12:53:15 dwmw2
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* Merge changes in 2.4.2
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*
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* Revision 1.1.1.1 1998/10/13 16:43:14 dwmw2
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* This'll screw the version control
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*
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* Revision 1.6 1998/09/30 00:40:38 dwmw2
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* Updated to use kernel's N_R3964 if available
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*
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* Revision 1.4 1998/04/02 20:29:44 lhaag
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* select, blocking, ...
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*
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* Revision 1.3 1998/02/12 18:58:43 root
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* fixed some memory leaks
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* calculation of checksum characters
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*
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* Revision 1.2 1998/02/07 13:03:17 root
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* ioctl read_telegram
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*
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* Revision 1.1 1998/02/06 19:19:43 root
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* Initial revision
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*
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*
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*/
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#ifndef __LINUX_N_R3964_H__
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#define __LINUX_N_R3964_H__
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#include <linux/param.h>
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#include <uapi/linux/n_r3964.h>
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/*
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* Common ascii handshake characters:
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*/
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#define STX 0x02
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#define ETX 0x03
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#define DLE 0x10
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#define NAK 0x15
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/*
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* Timeouts (from milliseconds to jiffies)
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*/
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#define R3964_TO_QVZ ((550)*HZ/1000)
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#define R3964_TO_ZVZ ((220)*HZ/1000)
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#define R3964_TO_NO_BUF ((400)*HZ/1000)
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#define R3964_NO_TX_ROOM ((100)*HZ/1000)
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#define R3964_TO_RX_PANIC ((4000)*HZ/1000)
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#define R3964_MAX_RETRIES 5
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enum { R3964_IDLE,
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R3964_TX_REQUEST, R3964_TRANSMITTING,
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R3964_WAIT_ZVZ_BEFORE_TX_RETRY, R3964_WAIT_FOR_TX_ACK,
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R3964_WAIT_FOR_RX_BUF,
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R3964_RECEIVING, R3964_WAIT_FOR_BCC, R3964_WAIT_FOR_RX_REPEAT
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};
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/*
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* All open file-handles are 'clients' and are stored in a linked list:
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*/
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struct r3964_message;
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struct r3964_client_info {
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spinlock_t lock;
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struct pid *pid;
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unsigned int sig_flags;
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struct r3964_client_info *next;
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struct r3964_message *first_msg;
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struct r3964_message *last_msg;
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struct r3964_block_header *next_block_to_read;
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int msg_count;
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};
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struct r3964_block_header;
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/* internal version of client_message: */
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struct r3964_message {
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int msg_id;
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int arg;
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int error_code;
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struct r3964_block_header *block;
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struct r3964_message *next;
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};
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/*
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* Header of received block in rx_buf/tx_buf:
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*/
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struct r3964_block_header
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{
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unsigned int length; /* length in chars without header */
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unsigned char *data; /* usually data is located
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immediately behind this struct */
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unsigned int locks; /* only used in rx_buffer */
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struct r3964_block_header *next;
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struct r3964_client_info *owner; /* =NULL in rx_buffer */
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};
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/*
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* If rx_buf hasn't enough space to store R3964_MTU chars,
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* we will reject all incoming STX-requests by sending NAK.
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*/
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#define RX_BUF_SIZE 4000
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#define TX_BUF_SIZE 4000
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#define R3964_MAX_BLOCKS_IN_RX_QUEUE 100
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#define R3964_PARITY 0x0001
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#define R3964_FRAME 0x0002
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#define R3964_OVERRUN 0x0004
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#define R3964_UNKNOWN 0x0008
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#define R3964_BREAK 0x0010
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#define R3964_CHECKSUM 0x0020
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#define R3964_ERROR 0x003f
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#define R3964_BCC 0x4000
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#define R3964_DEBUG 0x8000
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struct r3964_info {
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spinlock_t lock;
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struct tty_struct *tty;
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unsigned char priority;
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unsigned char *rx_buf; /* ring buffer */
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unsigned char *tx_buf;
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struct r3964_block_header *rx_first;
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struct r3964_block_header *rx_last;
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struct r3964_block_header *tx_first;
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struct r3964_block_header *tx_last;
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unsigned int tx_position;
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unsigned int rx_position;
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unsigned char last_rx;
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unsigned char bcc;
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unsigned int blocks_in_rx_queue;
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struct mutex read_lock; /* serialize r3964_read */
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struct r3964_client_info *firstClient;
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unsigned int state;
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unsigned int flags;
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struct timer_list tmr;
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int nRetry;
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};
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#endif
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