sound/oss/pas2_midi.c

   1 /*
   2  * sound/oss/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  * Bartlomiej Zolnierkiewicz    : Added __init to pas_init_mixer()
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/spinlock.h>
  18 #include "sound_config.h"
  19
  20 #include "pas2.h"
  21
  22 extern spinlock_t pas_lock;
  23
  24 static int      midi_busy, input_opened;
  25 static int      my_dev;
  26
  27 int pas2_mididev=-1;
  28
  29 static unsigned char tmp_queue[256];
  30 static volatile int qlen;
  31 static volatile unsigned char qhead, qtail;
  32
  33 static void     (*midi_input_intr) (int dev, unsigned char data);
  34
  35 static int pas_midi_open(int dev, int mode,
  36               void            (*input) (int dev, unsigned char data),
  37               void            (*output) (int dev)
  38 )
  39 {
  40         int             err;
  41         unsigned long   flags;
  42         unsigned char   ctrl;
  43
  44
  45         if (midi_busy)
  46                 return -EBUSY;
  47
  48         /*
  49          * Reset input and output FIFO pointers
  50          */
  51         pas_write(0x20 | 0x40,
  52                   0x178b);
  53
  54         spin_lock_irqsave(&pas_lock, flags);
  55
  56         if ((err = pas_set_intr(0x10)) < 0)
  57         {
  58                 spin_unlock_irqrestore(&pas_lock, flags);
  59                 return err;
  60         }
  61         /*
  62          * Enable input available and output FIFO empty interrupts
  63          */
  64
  65         ctrl = 0;
  66         input_opened = 0;
  67         midi_input_intr = input;
  68
  69         if (mode == OPEN_READ || mode == OPEN_READWRITE)
  70         {
  71                 ctrl |= 0x04;   /* Enable input */
  72                 input_opened = 1;
  73         }
  74         if (mode == OPEN_WRITE || mode == OPEN_READWRITE)
  75         {
  76                 ctrl |= 0x08 | 0x10;    /* Enable output */
  77         }
  78         pas_write(ctrl, 0x178b);
  79
  80         /*
  81          * Acknowledge any pending interrupts
  82          */
  83
  84         pas_write(0xff, 0x1B88);
  85
  86         spin_unlock_irqrestore(&pas_lock, flags);
  87
  88         midi_busy = 1;
  89         qlen = qhead = qtail = 0;
  90         return 0;
  91 }
  92
  93 static void pas_midi_close(int dev)
  94 {
  95
  96         /*
  97          * Reset FIFO pointers, disable intrs
  98          */
  99         pas_write(0x20 | 0x40, 0x178b);
 100
 101         pas_remove_intr(0x10);
 102         midi_busy = 0;
 103 }
 104
 105 static int dump_to_midi(unsigned char midi_byte)
 106 {
 107         int fifo_space, x;
 108
 109         fifo_space = ((x = pas_read(0x1B89)) >> 4) & 0x0f;
 110
 111         /*
 112          * The MIDI FIFO space register and it's documentation is nonunderstandable.
 113          * There seem to be no way to differentiate between buffer full and buffer
 114          * empty situations. For this reason we don't never write the buffer
 115          * completely full. In this way we can assume that 0 (or is it 15)
 116          * means that the buffer is empty.
 117          */
 118
 119         if (fifo_space < 2 && fifo_space != 0)  /* Full (almost) */
 120                 return 0;       /* Ask upper layers to retry after some time */
 121
 122         pas_write(midi_byte, 0x178A);
 123
 124         return 1;
 125 }
 126
 127 static int pas_midi_out(int dev, unsigned char midi_byte)
 128 {
 129
 130         unsigned long flags;
 131
 132         /*
 133          * Drain the local queue first
 134          */
 135
 136         spin_lock_irqsave(&pas_lock, flags);
 137
 138         while (qlen && dump_to_midi(tmp_queue[qhead]))
 139         {
 140                 qlen--;
 141                 qhead++;
 142         }
 143
 144         spin_unlock_irqrestore(&pas_lock, flags);
 145
 146         /*
 147          *      Output the byte if the local queue is empty.
 148          */
 149
 150         if (!qlen)
 151                 if (dump_to_midi(midi_byte))
 152                         return 1;
 153
 154         /*
 155          *      Put to the local queue
 156          */
 157
 158         if (qlen >= 256)
 159                 return 0;       /* Local queue full */
 160
 161         spin_lock_irqsave(&pas_lock, flags);
 162
 163         tmp_queue[qtail] = midi_byte;
 164         qlen++;
 165         qtail++;
 166
 167         spin_unlock_irqrestore(&pas_lock, 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         .owner          = THIS_MODULE,
 198         .info           = {"Pro Audio Spectrum", 0, 0, SNDCARD_PAS},
 199         .converter      = &std_midi_synth,
 200         .in_info        = {0},
 201         .open           = pas_midi_open,
 202         .close          = pas_midi_close,
 203         .outputc        = pas_midi_out,
 204         .start_read     = pas_midi_start_read,
 205         .end_read       = pas_midi_end_read,
 206         .kick           = pas_midi_kick,
 207         .buffer_status  = pas_buffer_status,
 208 };
 209
 210 void __init pas_midi_init(void)
 211 {
 212         int dev = sound_alloc_mididev();
 213
 214         if (dev == -1)
 215         {
 216                 printk(KERN_WARNING "pas_midi_init: Too many midi devices detected\n");
 217                 return;
 218         }
 219         std_midi_synth.midi_dev = my_dev = dev;
 220         midi_devs[dev] = &pas_midi_operations;
 221         pas2_mididev = dev;
 222         sequencer_init();
 223 }
 224
 225 void pas_midi_interrupt(void)
 226 {
 227         unsigned char   stat;
 228         int             i, incount;
 229
 230         stat = pas_read(0x1B88);
 231
 232         if (stat & 0x04)        /* Input data available */
 233         {
 234                 incount = pas_read(0x1B89) & 0x0f;      /* Input FIFO size */
 235                 if (!incount)
 236                         incount = 16;
 237
 238                 for (i = 0; i < incount; i++)
 239                         if (input_opened)
 240                         {
 241                                 midi_input_intr(my_dev, pas_read(0x178A));
 242                         } else
 243                                 pas_read(0x178A);       /* Flush */
 244         }
 245         if (stat & (0x08 | 0x10))
 246         {
 247                 spin_lock(&pas_lock);/* called in irq context */
 248
 249                 while (qlen && dump_to_midi(tmp_queue[qhead]))
 250                 {
 251                         qlen--;
 252                         qhead++;
 253                 }
 254
 255                 spin_unlock(&pas_lock);
 256         }
 257         if (stat & 0x40)
 258         {
 259                 printk(KERN_WARNING "MIDI output overrun %x,%x\n", pas_read(0x1B89), stat);
 260         }
 261         pas_write(stat, 0x1B88);        /* Acknowledge interrupts */
 262 }