i386/linux/linux-2.3.21/drivers/sound/pas2_midi.c

   1 /*
   2  * sound/pas2_midi.c
   3  *
   4  * The low level driver for the PAS Midi Interface.
   5  */
   6 /*
   7  * Copyright (C) by Hannu Savolainen 1993-1997
   8  *
   9  * OSS/Free for Linux is distributed under the GNU GENERAL PUBLIC LICENSE (GPL)
  10  * Version 2 (June 1991). See the "COPYING" file distributed with this software
  11  * for more info.
  12  */
  13 #include <linux/config.h>
  14
  15
  16 #include "sound_config.h"
  17
  18 #ifdef CONFIG_PAS
  19 #ifdef CONFIG_MIDI
  20
  21 static int      midi_busy = 0, input_opened = 0;
  22 static int      my_dev;
  23
  24 int pas2_mididev=-1;
  25
  26 static unsigned char tmp_queue[256];
  27 static volatile int qlen;
  28 static volatile unsigned char qhead, qtail;
  29
  30 static void     (*midi_input_intr) (int dev, unsigned char data);
  31
  32 static int pas_midi_open(int dev, int mode,
  33               void            (*input) (int dev, unsigned char data),
  34               void            (*output) (int dev)
  35 )
  36 {
  37         int             err;
  38         unsigned long   flags;
  39         unsigned char   ctrl;
  40
  41
  42         if (midi_busy)
  43                 return -EBUSY;
  44
  45         /*
  46          * Reset input and output FIFO pointers
  47          */
  48         pas_write(0x20 | 0x40,
  49                   0x178b);
  50
  51         save_flags(flags);
  52         cli();
  53
  54         if ((err = pas_set_intr(0x10)) < 0)
  55         {
  56                 restore_flags(flags);
  57                 return err;
  58         }
  59         /*
  60          * Enable input available and output FIFO empty interrupts
  61          */
  62
  63         ctrl = 0;
  64         input_opened = 0;
  65         midi_input_intr = input;
  66
  67         if (mode == OPEN_READ || mode == OPEN_READWRITE)
  68         {
  69                 ctrl |= 0x04;   /* Enable input */
  70                 input_opened = 1;
  71         }
  72         if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
  73         {
  74                 ctrl |= 0x08 | 0x10;    /* Enable output */
  75         }
  76         pas_write(ctrl, 0x178b);
  77
  78         /*
  79          * Acknowledge any pending interrupts
  80          */
  81
  82         pas_write(0xff, 0x1B88);
  83
  84         restore_flags(flags);
  85
  86         midi_busy = 1;
  87         qlen = qhead = qtail = 0;
  88         return 0;
  89 }
  90
  91 static void pas_midi_close(int dev)
  92 {
  93
  94         /*
  95          * Reset FIFO pointers, disable intrs
  96          */
  97         pas_write(0x20 | 0x40, 0x178b);
  98
  99         pas_remove_intr(0x10);
 100         midi_busy = 0;
 101 }
 102
 103 static int dump_to_midi(unsigned char midi_byte)
 104 {
 105         int fifo_space, x;
 106
 107         fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
 108
 109         /*
 110          * The MIDI FIFO space register and it's documentation is nonunderstandable.
 111          * There seem to be no way to differentiate between buffer full and buffer
 112          * empty situations. For this reason we don't never write the buffer
 113          * completely full. In this way we can assume that 0 (or is it 15)
 114          * means that the buffer is empty.
 115          */
 116
 117         if (fifo_space < 2 && fifo_space != 0)  /* Full (almost) */
 118                 return 0;       /* Ask upper layers to retry after some time */
 119
 120         pas_write(midi_byte, 0x178A);
 121
 122         return 1;
 123 }
 124
 125 static int pas_midi_out(int dev, unsigned char midi_byte)
 126 {
 127
 128         unsigned long flags;
 129
 130         /*
 131          * Drain the local queue first
 132          */
 133
 134         save_flags(flags);
 135         cli();
 136
 137         while (qlen && dump_to_midi(tmp_queue[qhead]))
 138         {
 139                 qlen--;
 140                 qhead++;
 141         }
 142
 143         restore_flags(flags);
 144
 145         /*
 146          *      Output the byte if the local queue is empty.
 147          */
 148
 149         if (!qlen)
 150                 if (dump_to_midi(midi_byte))
 151                         return 1;
 152
 153         /*
 154          *      Put to the local queue
 155          */
 156
 157         if (qlen >= 256)
 158                 return 0;       /* Local queue full */
 159
 160         save_flags(flags);
 161         cli();
 162
 163         tmp_queue[qtail] = midi_byte;
 164         qlen++;
 165         qtail++;
 166
 167         restore_flags(flags);
 168
 169         return 1;
 170 }
 171
 172 static int pas_midi_start_read(int dev)
 173 {
 174         return 0;
 175 }
 176
 177 static int pas_midi_end_read(int dev)
 178 {
 179         return 0;
 180 }
 181
 182 static void pas_midi_kick(int dev)
 183 {
 184 }
 185
 186 static int pas_buffer_status(int dev)
 187 {
 188         return qlen;
 189 }
 190
 191 #define MIDI_SYNTH_NAME "Pro Audio Spectrum Midi"
 192 #define MIDI_SYNTH_CAPS SYNTH_CAP_INPUT
 193 #include "midi_synth.h"
 194
 195 static struct midi_operations pas_midi_operations =
 196 {
 197         {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
 198         &std_midi_synth,
 199         {0},
 200         pas_midi_open,
 201         pas_midi_close,
 202         NULL,
 203         pas_midi_out,
 204         pas_midi_start_read,
 205         pas_midi_end_read,
 206         pas_midi_kick,
 207         NULL,
 208         pas_buffer_status,
 209         NULL
 210 };
 211
 212 void pas_midi_init(void)
 213 {
 214         int dev = sound_alloc_mididev();
 215
 216         if (dev == -1)
 217         {
 218                 printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n");
 219                 return;
 220         }
 221         std_midi_synth.midi_dev = my_dev = dev;
 222         midi_devs[dev] = &pas_midi_operations;
 223         pas2_mididev = dev;
 224         sequencer_init();
 225 }
 226
 227 void pas_midi_interrupt(void)
 228 {
 229         unsigned char   stat;
 230         int             i, incount;
 231         unsigned long   flags;
 232
 233         stat = pas_read(0x1B88);
 234
 235         if (stat & 0x04)        /* Input data available */
 236         {
 237                 incount = pas_read(0x1B89) & 0x0f;      /* Input FIFO size */
 238                 if (!incount)
 239                         incount = 16;
 240
 241                 for (i = 0; i < incount; i++)
 242                         if (input_opened)
 243                         {
 244                                 midi_input_intr(my_dev, pas_read(0x178A));
 245                         } else
 246                                 pas_read(0x178A);       /* Flush */
 247         }
 248         if (stat & (0x08 | 0x10))
 249         {
 250                 save_flags(flags);
 251                 cli();
 252
 253                 while (qlen && dump_to_midi(tmp_queue[qhead]))
 254                 {
 255                         qlen--;
 256                         qhead++;
 257                 }
 258
 259                 restore_flags(flags);
 260         }
 261         if (stat & 0x40)
 262         {
 263                 printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
 264         }
 265         pas_write(stat, 0x1B88);        /* Acknowledge interrupts */
 266 }
 267
 268 #endif
 269 #endif