FreeBSD/Linux Kernel Cross Reference
sys/dev/midivar.h

     /*      $NetBSD: midivar.h,v 1.20 2014/12/22 07:02:22 mrg Exp $ */
     
     /*
      * Copyright (c) 1998, 2008 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * This code is derived from software contributed to The NetBSD Foundation
      * by Lennart Augustsson (augustss@NetBSD.org) and (midi FST refactoring and
      * Active Sense) Chapman Flack (chap@NetBSD.org).
     *
     * 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.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 THE FOUNDATION 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.
     */
    
    #ifndef _SYS_DEV_MIDIVAR_H_
    #define _SYS_DEV_MIDIVAR_H_
    
    #define MIDI_BUFSIZE 1024
    
    #include <sys/callout.h>
    #include <sys/cdefs.h>
    #include <sys/device.h>
    #include <sys/condvar.h>
    #include <sys/mutex.h>
    
    /*
     * In both xmt and rcv direction, the midi_fst runs at the time data are
     * buffered (midi_writebytes for xmt, midi_in for rcv) so what's in the
     * buffer is always in canonical form (or compressed, on xmt, if the hw
     * wants it that way). To preserve message boundaries for the buffer
     * consumer, but allow transfers larger than one message, the buffer is
     * split into a buf fork and an idx fork, where each byte of idx encodes
     * the type and length of a message. Because messages are variable length,
     * it is a guess how to set the relative sizes of idx and buf, or how many
     * messages can be buffered before one or the other fills.
     *
     * The producer adds only complete messages to a buffer (except for SysEx
     * messages, which have unpredictable length). A consumer serving byte-at-a-
     * time hardware may partially consume a message, in which case it updates
     * the length count at *idx_consumerp to reflect the remaining length of the
     * message, only incrementing idx_consumerp when the message has been entirely
     * consumed.
     *
     * The buffers are structured in the simple 1 reader 1 writer bounded buffer
     * form, considered full when 1 unused byte remains. This should allow their
     * use with minimal locking provided single pointer reads and writes can be
     * assured atomic ... but then I chickened out on assuming that assurance, and
     * added the extra locks to the code.
     *
     * Macros for manipulating the buffers:
     *
     * MIDI_BUF_DECLARE(frk) where frk is either buf or idx:
     *   declares the local variables frk_cur, frk_lim, frk_org, and frk_end.
     *
     * MIDI_BUF_CONSUMER_INIT(mb,frk)
     * MIDI_BUF_PRODUCER_INIT(mb,frk)
     *   initializes frk_org and frk_end to the base and end (that is, address just
     *   past the last valid byte) of the buffer fork frk, frk_cur to the
     *   consumer's or producer's current position, respectively, and frk_lim to
     *   the current limit (for either consumer or producer, immediately following
     *   this macro, frk_lim-frk_cur gives the number of bytes to play with). That
     *   means frk_lim may actually point past the buffer; loops on the condition
     *   (frk_cur < frk_lim) must contain WRAP(frk) if proceeding byte-by-byte, or
     *   must explicitly handle wrapping around frk_end if doing anything clever.
     *   These are expression-shaped macros that have the value frk_lim. When used
     *   without locking--provided pointer reads and writes can be assumed atomic--
     *   these macros give a conservative estimate of what is available to consume
     *   or produce.
     *
     * MIDI_BUF_WRAP(frk)
     *   tests whether frk_cur == frk_end and, if so, wraps both frk_cur and
     *   frk_lim around the beginning of the buffer. Because the test is ==, it
     *   must be applied at each byte in a loop; if the loop is proceeding in
     *   bigger steps, the possibility of wrap must be coded for. This expression-
     *   shaped macro has the value of frk_cur after wrapping.
     *
     * MIDI_BUF_CONSUMER_REFRESH(mb,frk)
     * MIDI_BUF_PRODUCER_REFRESH(mb,frk)
     *   refresh the local value frk_lim for a new snapshot of bytes available; an
     *   expression-shaped macro with the new value of frk_lim. Usually used after
     *   using up the first conservative estimate and obtaining a lock to get a
    *   final value. Used unlocked, just gives a more recent conservative estimate.
    *
    * MIDI_BUF_CONSUMER_WBACK(mb,frk)
    * MIDI_BUF_PRODUCER_WBACK(mb,frk)
    *   write back the local copy of frk_cur to the buffer, after a barrier to
    *   ensure prior writes go first. Under the right atomicity conditions a
    *   producer could get away with using these unlocked, as long as the order
    *   is buf followed by idx. A consumer should update both in a critical
    *   section.
    */
   struct midi_buffer {
           u_char * __volatile idx_producerp;
           u_char * __volatile idx_consumerp;
           u_char * __volatile buf_producerp;
           u_char * __volatile buf_consumerp;
           u_char idx[MIDI_BUFSIZE/3];
           u_char buf[MIDI_BUFSIZE-MIDI_BUFSIZE/3];
   };
   #define MIDI_BUF_DECLARE(frk) \
   u_char *__CONCAT(frk,_cur); \
   u_char *__CONCAT(frk,_lim); \
   u_char *__CONCAT(frk,_org); \
   u_char *__CONCAT(frk,_end)
   
   #define MIDI_BUF_CONSUMER_REFRESH(mb,frk) \
   ((__CONCAT(frk,_lim)=(mb)->__CONCAT(frk,_producerp)), \
   __CONCAT(frk,_lim) < __CONCAT(frk,_cur) ? \
   (__CONCAT(frk,_lim) += sizeof (mb)->frk) : __CONCAT(frk,_lim))
   
   #define MIDI_BUF_PRODUCER_REFRESH(mb,frk) \
   ((__CONCAT(frk,_lim)=(mb)->__CONCAT(frk,_consumerp)-1), \
   __CONCAT(frk,_lim) < __CONCAT(frk,_cur) ? \
   (__CONCAT(frk,_lim) += sizeof (mb)->frk) : __CONCAT(frk,_lim))
   
   #define MIDI_BUF_EXTENT_INIT(mb,frk) \
   ((__CONCAT(frk,_org)=(mb)->frk), \
   (__CONCAT(frk,_end)=__CONCAT(frk,_org)+sizeof (mb)->frk))
   
   #define MIDI_BUF_CONSUMER_INIT(mb,frk) \
   (MIDI_BUF_EXTENT_INIT((mb),frk), \
   (__CONCAT(frk,_cur)=(mb)->__CONCAT(frk,_consumerp)), \
   MIDI_BUF_CONSUMER_REFRESH((mb),frk))
   
   #define MIDI_BUF_PRODUCER_INIT(mb,frk) \
   (MIDI_BUF_EXTENT_INIT((mb),frk), \
   (__CONCAT(frk,_cur)=(mb)->__CONCAT(frk,_producerp)), \
   MIDI_BUF_PRODUCER_REFRESH((mb),frk))
   
   #define MIDI_BUF_WRAP(frk) \
   (__predict_false(__CONCAT(frk,_cur)==__CONCAT(frk,_end)) ? (\
   (__CONCAT(frk,_lim)-=__CONCAT(frk,_end)-__CONCAT(frk,_org)), \
   (__CONCAT(frk,_cur)=__CONCAT(frk,_org))) : __CONCAT(frk,_cur))
   
   #define MIDI_BUF_CONSUMER_WBACK(mb,frk) do { \
   __insn_barrier(); \
   (mb)->__CONCAT(frk,_consumerp)=__CONCAT(frk,_cur); \
   } while (/*CONSTCOND*/0)
   
   #define MIDI_BUF_PRODUCER_WBACK(mb,frk) do { \
   __insn_barrier(); \
   (mb)->__CONCAT(frk,_producerp)=__CONCAT(frk,_cur); \
   } while (/*CONSTCOND*/0)
   
   
   #define MIDI_MAX_WRITE 32       /* max bytes written with busy wait */
   #define MIDI_WAIT 10000         /* microseconds to wait after busy wait */
   
   struct midi_state {
           struct  evcnt bytesDiscarded;
           struct  evcnt incompleteMessages;
           struct {
                   uint32_t bytesDiscarded;
                   uint32_t incompleteMessages;
           }       atOpen,
                   atQuery;
           int     state;
           u_char *pos;
           u_char *end;
           u_char  msg[3];
   };
   
   struct midi_softc {
           device_t dev;           /* Hardware device struct */
           void    *hw_hdl;        /* Hardware driver handle */
           const struct    midi_hw_if *hw_if; /* Hardware interface */
           const struct    midi_hw_if_ext *hw_if_ext; /* see midi_if.h */
           int     isopen;         /* Open indicator */
           int     flags;          /* Open flags */
           int     dying;
           struct  midi_buffer outbuf;
           struct  midi_buffer inbuf;
           int     props;
           int     refcnt;
           kcondvar_t detach_cv;
           kcondvar_t rchan;
           kcondvar_t wchan;
           kmutex_t *lock;
           int     pbus;
           int     rcv_expect_asense;
           int     rcv_quiescent;
           int     rcv_eof;
           struct  selinfo wsel;   /* write selector */
           struct  selinfo rsel;   /* read selector */
           pid_t   async;  /* process who wants audio SIGIO */
           void    *sih;
   
           struct callout xmt_asense_co;
           struct callout rcv_asense_co;
   
           /* MIDI input state machine; states are *s of 4 to allow | CAT bits */
           struct midi_state rcv;
           struct midi_state xmt;
   #define MIDI_IN_START   0
   #define MIDI_IN_RUN0_1  4
   #define MIDI_IN_RUN1_1  8
   #define MIDI_IN_RUN0_2 12
   #define MIDI_IN_RUN1_2 16
   #define MIDI_IN_RUN2_2 20
   #define MIDI_IN_COM0_1 24
   #define MIDI_IN_COM0_2 28
   #define MIDI_IN_COM1_2 32
   #define MIDI_IN_SYX1_3 36
   #define MIDI_IN_SYX2_3 40
   #define MIDI_IN_SYX0_3 44
   #define MIDI_IN_RNX0_1 48
   #define MIDI_IN_RNX0_2 52
   #define MIDI_IN_RNX1_2 56
   #define MIDI_IN_RNY1_2 60 /* not needed except for accurate error counts */
   /*
    * Four more states are needed to model the equivalence of NoteOff vel. 64
    * and NoteOn vel. 0 for canonicalization or compression. In each of these 4
    * states, we know the last message input and output was a NoteOn or a NoteOff.
    */
   #define MIDI_IN_RXX2_2 64 /* last output == msg[0] != last input */
   #define MIDI_IN_RXX0_2 68 /* last output != msg[0] == this input */
   #define MIDI_IN_RXX1_2 72 /* " */
   #define MIDI_IN_RXY1_2 76 /* variant of RXX1_2 needed for error count only */
   
   #define MIDI_CAT_DATA 0
   #define MIDI_CAT_STATUS1 1
   #define MIDI_CAT_STATUS2 2
   #define MIDI_CAT_COMMON 3
   
           /* Synthesizer emulation stuff */
           int     seqopen;
           struct  midi_dev *seq_md; /* structure that links us with the seq. */
   };
   
   #define MIDIUNIT(d) ((d) & 0xff)
   
   #endif /* _SYS_DEV_MIDIVAR_H_ */

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