linux/arch/m68k/q40/q40ints.c
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   1/*
   2 * arch/m68k/q40/q40ints.c
   3 *
   4 * Copyright (C) 1999,2001 Richard Zidlicky
   5 *
   6 * This file is subject to the terms and conditions of the GNU General Public
   7 * License.  See the file COPYING in the main directory of this archive
   8 * for more details.
   9 *
  10 * .. used to be loosely based on bvme6000ints.c
  11 *
  12 */
  13
  14#include <linux/types.h>
  15#include <linux/kernel.h>
  16#include <linux/errno.h>
  17#include <linux/interrupt.h>
  18#include <linux/irq.h>
  19
  20#include <asm/machdep.h>
  21#include <asm/ptrace.h>
  22#include <asm/traps.h>
  23
  24#include <asm/q40_master.h>
  25#include <asm/q40ints.h>
  26
  27/*
  28 * Q40 IRQs are defined as follows:
  29 *            3,4,5,6,7,10,11,14,15 : ISA dev IRQs
  30 *            16-31: reserved
  31 *            32   : keyboard int
  32 *            33   : frame int (50/200 Hz periodic timer)
  33 *            34   : sample int (10/20 KHz periodic timer)
  34 *
  35*/
  36
  37static void q40_irq_handler(unsigned int, struct pt_regs *fp);
  38static void q40_irq_enable(struct irq_data *data);
  39static void q40_irq_disable(struct irq_data *data);
  40
  41unsigned short q40_ablecount[35];
  42unsigned short q40_state[35];
  43
  44static unsigned int q40_irq_startup(struct irq_data *data)
  45{
  46        unsigned int irq = data->irq;
  47
  48        /* test for ISA ints not implemented by HW */
  49        switch (irq) {
  50        case 1: case 2: case 8: case 9:
  51        case 11: case 12: case 13:
  52                pr_warn("%s: ISA IRQ %d not implemented by HW\n", __func__,
  53                        irq);
  54                /* FIXME return -ENXIO; */
  55        }
  56        return 0;
  57}
  58
  59static void q40_irq_shutdown(struct irq_data *data)
  60{
  61}
  62
  63static struct irq_chip q40_irq_chip = {
  64        .name           = "q40",
  65        .irq_startup    = q40_irq_startup,
  66        .irq_shutdown   = q40_irq_shutdown,
  67        .irq_enable     = q40_irq_enable,
  68        .irq_disable    = q40_irq_disable,
  69};
  70
  71/*
  72 * void q40_init_IRQ (void)
  73 *
  74 * Parameters:  None
  75 *
  76 * Returns:     Nothing
  77 *
  78 * This function is called during kernel startup to initialize
  79 * the q40 IRQ handling routines.
  80 */
  81
  82static int disabled;
  83
  84void __init q40_init_IRQ(void)
  85{
  86        m68k_setup_irq_controller(&q40_irq_chip, handle_simple_irq, 1,
  87                                  Q40_IRQ_MAX);
  88
  89        /* setup handler for ISA ints */
  90        m68k_setup_auto_interrupt(q40_irq_handler);
  91
  92        m68k_irq_startup_irq(IRQ_AUTO_2);
  93        m68k_irq_startup_irq(IRQ_AUTO_4);
  94
  95        /* now enable some ints.. */
  96        master_outb(1, EXT_ENABLE_REG);  /* ISA IRQ 5-15 */
  97
  98        /* make sure keyboard IRQ is disabled */
  99        master_outb(0, KEY_IRQ_ENABLE_REG);
 100}
 101
 102
 103/*
 104 * this stuff doesn't really belong here..
 105 */
 106
 107int ql_ticks;              /* 200Hz ticks since last jiffie */
 108static int sound_ticks;
 109
 110#define SVOL 45
 111
 112void q40_mksound(unsigned int hz, unsigned int ticks)
 113{
 114        /* for now ignore hz, except that hz==0 switches off sound */
 115        /* simply alternate the ampl (128-SVOL)-(128+SVOL)-..-.. at 200Hz */
 116        if (hz == 0) {
 117                if (sound_ticks)
 118                        sound_ticks = 1;
 119
 120                *DAC_LEFT = 128;
 121                *DAC_RIGHT = 128;
 122
 123                return;
 124        }
 125        /* sound itself is done in q40_timer_int */
 126        if (sound_ticks == 0)
 127                sound_ticks = 1000; /* pretty long beep */
 128        sound_ticks = ticks << 1;
 129}
 130
 131static irqreturn_t q40_timer_int(int irq, void *dev_id)
 132{
 133        ql_ticks = ql_ticks ? 0 : 1;
 134        if (sound_ticks) {
 135                unsigned char sval=(sound_ticks & 1) ? 128-SVOL : 128+SVOL;
 136                sound_ticks--;
 137                *DAC_LEFT=sval;
 138                *DAC_RIGHT=sval;
 139        }
 140
 141        if (!ql_ticks) {
 142                unsigned long flags;
 143
 144                local_irq_save(flags);
 145                legacy_timer_tick(1);
 146                timer_heartbeat();
 147                local_irq_restore(flags);
 148        }
 149        return IRQ_HANDLED;
 150}
 151
 152void q40_sched_init (void)
 153{
 154        int timer_irq;
 155
 156        timer_irq = Q40_IRQ_FRAME;
 157
 158        if (request_irq(timer_irq, q40_timer_int, 0, "timer", NULL))
 159                panic("Couldn't register timer int");
 160
 161        master_outb(-1, FRAME_CLEAR_REG);
 162        master_outb( 1, FRAME_RATE_REG);
 163}
 164
 165
 166/*
 167 * tables to translate bits into IRQ numbers
 168 * it is a good idea to order the entries by priority
 169 *
 170*/
 171
 172struct IRQ_TABLE{ unsigned mask; int irq ;};
 173#if 0
 174static struct IRQ_TABLE iirqs[]={
 175  {Q40_IRQ_FRAME_MASK,Q40_IRQ_FRAME},
 176  {Q40_IRQ_KEYB_MASK,Q40_IRQ_KEYBOARD},
 177  {0,0}};
 178#endif
 179static struct IRQ_TABLE eirqs[] = {
 180  { .mask = Q40_IRQ3_MASK,      .irq = 3 },     /* ser 1 */
 181  { .mask = Q40_IRQ4_MASK,      .irq = 4 },     /* ser 2 */
 182  { .mask = Q40_IRQ14_MASK,     .irq = 14 },    /* IDE 1 */
 183  { .mask = Q40_IRQ15_MASK,     .irq = 15 },    /* IDE 2 */
 184  { .mask = Q40_IRQ6_MASK,      .irq = 6 },     /* floppy, handled elsewhere */
 185  { .mask = Q40_IRQ7_MASK,      .irq = 7 },     /* par */
 186  { .mask = Q40_IRQ5_MASK,      .irq = 5 },
 187  { .mask = Q40_IRQ10_MASK,     .irq = 10 },
 188  {0,0}
 189};
 190
 191/* complain only this many times about spurious ints : */
 192static int ccleirq=60;    /* ISA dev IRQs*/
 193/*static int cclirq=60;*/     /* internal */
 194
 195/* FIXME: add shared ints,mask,unmask,probing.... */
 196
 197#define IRQ_INPROGRESS 1
 198/*static unsigned short saved_mask;*/
 199//static int do_tint=0;
 200
 201#define DEBUG_Q40INT
 202/*#define IP_USE_DISABLE *//* would be nice, but crashes ???? */
 203
 204static int mext_disabled=0;  /* ext irq disabled by master chip? */
 205static int aliased_irq=0;  /* how many times inside handler ?*/
 206
 207
 208/* got interrupt, dispatch to ISA or keyboard/timer IRQs */
 209static void q40_irq_handler(unsigned int irq, struct pt_regs *fp)
 210{
 211        unsigned mir, mer;
 212        int i;
 213
 214//repeat:
 215        mir = master_inb(IIRQ_REG);
 216#ifdef CONFIG_BLK_DEV_FD
 217        if ((mir & Q40_IRQ_EXT_MASK) &&
 218            (master_inb(EIRQ_REG) & Q40_IRQ6_MASK)) {
 219                floppy_hardint();
 220                return;
 221        }
 222#endif
 223        switch (irq) {
 224        case 4:
 225        case 6:
 226                do_IRQ(Q40_IRQ_SAMPLE, fp);
 227                return;
 228        }
 229        if (mir & Q40_IRQ_FRAME_MASK) {
 230                do_IRQ(Q40_IRQ_FRAME, fp);
 231                master_outb(-1, FRAME_CLEAR_REG);
 232        }
 233        if ((mir & Q40_IRQ_SER_MASK) || (mir & Q40_IRQ_EXT_MASK)) {
 234                mer = master_inb(EIRQ_REG);
 235                for (i = 0; eirqs[i].mask; i++) {
 236                        if (mer & eirqs[i].mask) {
 237                                irq = eirqs[i].irq;
 238/*
 239 * There is a little mess wrt which IRQ really caused this irq request. The
 240 * main problem is that IIRQ_REG and EIRQ_REG reflect the state when they
 241 * are read - which is long after the request came in. In theory IRQs should
 242 * not just go away but they occasionally do
 243 */
 244                                if (irq > 4 && irq <= 15 && mext_disabled) {
 245                                        /*aliased_irq++;*/
 246                                        goto iirq;
 247                                }
 248                                if (q40_state[irq] & IRQ_INPROGRESS) {
 249                                        /* some handlers do local_irq_enable() for irq latency reasons, */
 250                                        /* however reentering an active irq handler is not permitted */
 251#ifdef IP_USE_DISABLE
 252                                        /* in theory this is the better way to do it because it still */
 253                                        /* lets through eg the serial irqs, unfortunately it crashes */
 254                                        disable_irq(irq);
 255                                        disabled = 1;
 256#else
 257                                        /*pr_warn("IRQ_INPROGRESS detected for irq %d, disabling - %s disabled\n",
 258                                                irq, disabled ? "already" : "not yet"); */
 259                                        fp->sr = (((fp->sr) & (~0x700))+0x200);
 260                                        disabled = 1;
 261#endif
 262                                        goto iirq;
 263                                }
 264                                q40_state[irq] |= IRQ_INPROGRESS;
 265                                do_IRQ(irq, fp);
 266                                q40_state[irq] &= ~IRQ_INPROGRESS;
 267
 268                                /* naively enable everything, if that fails than    */
 269                                /* this function will be reentered immediately thus */
 270                                /* getting another chance to disable the IRQ        */
 271
 272                                if (disabled) {
 273#ifdef IP_USE_DISABLE
 274                                        if (irq > 4) {
 275                                                disabled = 0;
 276                                                enable_irq(irq);
 277                                        }
 278#else
 279                                        disabled = 0;
 280                                        /*pr_info("reenabling irq %d\n", irq); */
 281#endif
 282                                }
 283// used to do 'goto repeat;' here, this delayed bh processing too long
 284                                return;
 285                        }
 286                }
 287                if (mer && ccleirq > 0 && !aliased_irq) {
 288                        pr_warn("ISA interrupt from unknown source? EIRQ_REG = %x\n",
 289                                mer);
 290                        ccleirq--;
 291                }
 292        }
 293 iirq:
 294        mir = master_inb(IIRQ_REG);
 295        /* should test whether keyboard irq is really enabled, doing it in defhand */
 296        if (mir & Q40_IRQ_KEYB_MASK)
 297                do_IRQ(Q40_IRQ_KEYBOARD, fp);
 298
 299        return;
 300}
 301
 302void q40_irq_enable(struct irq_data *data)
 303{
 304        unsigned int irq = data->irq;
 305
 306        if (irq >= 5 && irq <= 15) {
 307                mext_disabled--;
 308                if (mext_disabled > 0)
 309                        pr_warn("q40_irq_enable : nested disable/enable\n");
 310                if (mext_disabled == 0)
 311                        master_outb(1, EXT_ENABLE_REG);
 312        }
 313}
 314
 315
 316void q40_irq_disable(struct irq_data *data)
 317{
 318        unsigned int irq = data->irq;
 319
 320        /* disable ISA iqs : only do something if the driver has been
 321         * verified to be Q40 "compatible" - right now IDE, NE2K
 322         * Any driver should not attempt to sleep across disable_irq !!
 323         */
 324
 325        if (irq >= 5 && irq <= 15) {
 326                master_outb(0, EXT_ENABLE_REG);
 327                mext_disabled++;
 328                if (mext_disabled > 1)
 329                        pr_info("disable_irq nesting count %d\n",
 330                                mext_disabled);
 331        }
 332}
 333