arch/m68k/mac/oss.c

   1 /*
   2  *      OSS handling
   3  *      Written by Joshua M. Thompson (funaho@jurai.org)
   4  *
   5  *
   6  *      This chip is used in the IIfx in place of VIA #2. It acts like a fancy
   7  *      VIA chip with prorammable interrupt levels.
   8  *
   9  * 990502 (jmt) - Major rewrite for new interrupt architecture as well as some
  10  *                recent insights into OSS operational details.
  11  * 990610 (jmt) - Now taking full advantage of the OSS. Interrupts are mapped
  12  *                to mostly match the A/UX interrupt scheme supported on the
  13  *                VIA side. Also added support for enabling the ISM irq again
  14  *                since we now have a functional IOP manager.
  15  */
  16
  17 #include <linux/types.h>
  18 #include <linux/kernel.h>
  19 #include <linux/mm.h>
  20 #include <linux/delay.h>
  21 #include <linux/init.h>
  22
  23 #include <asm/bootinfo.h>
  24 #include <asm/machw.h>
  25 #include <asm/macintosh.h>
  26 #include <asm/macints.h>
  27 #include <asm/mac_via.h>
  28 #include <asm/mac_oss.h>
  29
  30 int oss_present;
  31 volatile struct mac_oss *oss;
  32
  33 static irqreturn_t oss_irq(int, void *);
  34 static irqreturn_t oss_nubus_irq(int, void *);
  35
  36 extern irqreturn_t via1_irq(int, void *);
  37 extern irqreturn_t mac_scc_dispatch(int, void *);
  38
  39 /*
  40  * Initialize the OSS
  41  *
  42  * The OSS "detection" code is actually in via_init() which is always called
  43  * before us. Thus we can count on oss_present being valid on entry.
  44  */
  45
  46 void __init oss_init(void)
  47 {
  48         int i;
  49
  50         if (!oss_present) return;
  51
  52         oss = (struct mac_oss *) OSS_BASE;
  53
  54         /* Disable all interrupts. Unlike a VIA it looks like we    */
  55         /* do this by setting the source's interrupt level to zero. */
  56
  57         for (i = 0; i <= OSS_NUM_SOURCES; i++) {
  58                 oss->irq_level[i] = OSS_IRQLEV_DISABLED;
  59         }
  60         /* If we disable VIA1 here, we never really handle it... */
  61         oss->irq_level[OSS_VIA1] = OSS_IRQLEV_VIA1;
  62 }
  63
  64 /*
  65  * Register the OSS and NuBus interrupt dispatchers.
  66  */
  67
  68 void __init oss_register_interrupts(void)
  69 {
  70         request_irq(OSS_IRQLEV_SCSI, oss_irq, IRQ_FLG_LOCK,
  71                         "scsi", (void *) oss);
  72         request_irq(OSS_IRQLEV_IOPSCC, mac_scc_dispatch, IRQ_FLG_LOCK,
  73                         "scc", mac_scc_dispatch);
  74         request_irq(OSS_IRQLEV_NUBUS, oss_nubus_irq, IRQ_FLG_LOCK,
  75                         "nubus", (void *) oss);
  76         request_irq(OSS_IRQLEV_SOUND, oss_irq, IRQ_FLG_LOCK,
  77                         "sound", (void *) oss);
  78         request_irq(OSS_IRQLEV_VIA1, via1_irq, IRQ_FLG_LOCK,
  79                         "via1", (void *) via1);
  80 }
  81
  82 /*
  83  * Initialize OSS for Nubus access
  84  */
  85
  86 void __init oss_nubus_init(void)
  87 {
  88 }
  89
  90 /*
  91  * Handle miscellaneous OSS interrupts. Right now that's just sound
  92  * and SCSI; everything else is routed to its own autovector IRQ.
  93  */
  94
  95 static irqreturn_t oss_irq(int irq, void *dev_id)
  96 {
  97         int events;
  98
  99         events = oss->irq_pending & (OSS_IP_SOUND|OSS_IP_SCSI);
 100         if (!events)
 101                 return IRQ_NONE;
 102
 103 #ifdef DEBUG_IRQS
 104         if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
 105                 printk("oss_irq: irq %d events = 0x%04X\n", irq,
 106                         (int) oss->irq_pending);
 107         }
 108 #endif
 109         /* FIXME: how do you clear a pending IRQ?    */
 110
 111         if (events & OSS_IP_SOUND) {
 112                 oss->irq_pending &= ~OSS_IP_SOUND;
 113                 /* FIXME: call sound handler */
 114         } else if (events & OSS_IP_SCSI) {
 115                 oss->irq_pending &= ~OSS_IP_SCSI;
 116                 m68k_handle_int(IRQ_MAC_SCSI);
 117         } else {
 118                 /* FIXME: error check here? */
 119         }
 120         return IRQ_HANDLED;
 121 }
 122
 123 /*
 124  * Nubus IRQ handler, OSS style
 125  *
 126  * Unlike the VIA/RBV this is on its own autovector interrupt level.
 127  */
 128
 129 static irqreturn_t oss_nubus_irq(int irq, void *dev_id)
 130 {
 131         int events, irq_bit, i;
 132
 133         events = oss->irq_pending & OSS_IP_NUBUS;
 134         if (!events)
 135                 return IRQ_NONE;
 136
 137 #ifdef DEBUG_NUBUS_INT
 138         if (console_loglevel > 7) {
 139                 printk("oss_nubus_irq: events = 0x%04X\n", events);
 140         }
 141 #endif
 142         /* There are only six slots on the OSS, not seven */
 143
 144         i = 6;
 145         irq_bit = 0x40;
 146         do {
 147                 --i;
 148                 irq_bit >>= 1;
 149                 if (events & irq_bit) {
 150                         oss->irq_pending &= ~irq_bit;
 151                         m68k_handle_int(NUBUS_SOURCE_BASE + i);
 152                 }
 153         } while(events & (irq_bit - 1));
 154         return IRQ_HANDLED;
 155 }
 156
 157 /*
 158  * Enable an OSS interrupt
 159  *
 160  * It looks messy but it's rather straightforward. The switch() statement
 161  * just maps the machspec interrupt numbers to the right OSS interrupt
 162  * source (if the OSS handles that interrupt) and then sets the interrupt
 163  * level for that source to nonzero, thus enabling the interrupt.
 164  */
 165
 166 void oss_irq_enable(int irq) {
 167 #ifdef DEBUG_IRQUSE
 168         printk("oss_irq_enable(%d)\n", irq);
 169 #endif
 170         switch(irq) {
 171                 case IRQ_SCC:
 172                 case IRQ_SCCA:
 173                 case IRQ_SCCB:
 174                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
 175                         break;
 176                 case IRQ_MAC_ADB:
 177                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
 178                         break;
 179                 case IRQ_MAC_SCSI:
 180                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
 181                         break;
 182                 case IRQ_NUBUS_9:
 183                 case IRQ_NUBUS_A:
 184                 case IRQ_NUBUS_B:
 185                 case IRQ_NUBUS_C:
 186                 case IRQ_NUBUS_D:
 187                 case IRQ_NUBUS_E:
 188                         irq -= NUBUS_SOURCE_BASE;
 189                         oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
 190                         break;
 191 #ifdef DEBUG_IRQUSE
 192                 default:
 193                         printk("%s unknown irq %d\n", __func__, irq);
 194                         break;
 195 #endif
 196         }
 197 }
 198
 199 /*
 200  * Disable an OSS interrupt
 201  *
 202  * Same as above except we set the source's interrupt level to zero,
 203  * to disable the interrupt.
 204  */
 205
 206 void oss_irq_disable(int irq) {
 207 #ifdef DEBUG_IRQUSE
 208         printk("oss_irq_disable(%d)\n", irq);
 209 #endif
 210         switch(irq) {
 211                 case IRQ_SCC:
 212                 case IRQ_SCCA:
 213                 case IRQ_SCCB:
 214                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_DISABLED;
 215                         break;
 216                 case IRQ_MAC_ADB:
 217                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_DISABLED;
 218                         break;
 219                 case IRQ_MAC_SCSI:
 220                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_DISABLED;
 221                         break;
 222                 case IRQ_NUBUS_9:
 223                 case IRQ_NUBUS_A:
 224                 case IRQ_NUBUS_B:
 225                 case IRQ_NUBUS_C:
 226                 case IRQ_NUBUS_D:
 227                 case IRQ_NUBUS_E:
 228                         irq -= NUBUS_SOURCE_BASE;
 229                         oss->irq_level[irq] = OSS_IRQLEV_DISABLED;
 230                         break;
 231 #ifdef DEBUG_IRQUSE
 232                 default:
 233                         printk("%s unknown irq %d\n", __func__, irq);
 234                         break;
 235 #endif
 236         }
 237 }
 238
 239 /*
 240  * Clear an OSS interrupt
 241  *
 242  * Not sure if this works or not but it's the only method I could
 243  * think of based on the contents of the mac_oss structure.
 244  */
 245
 246 void oss_irq_clear(int irq) {
 247         /* FIXME: how to do this on OSS? */
 248         switch(irq) {
 249                 case IRQ_SCC:
 250                 case IRQ_SCCA:
 251                 case IRQ_SCCB:
 252                         oss->irq_pending &= ~OSS_IP_IOPSCC;
 253                         break;
 254                 case IRQ_MAC_ADB:
 255                         oss->irq_pending &= ~OSS_IP_IOPISM;
 256                         break;
 257                 case IRQ_MAC_SCSI:
 258                         oss->irq_pending &= ~OSS_IP_SCSI;
 259                         break;
 260                 case IRQ_NUBUS_9:
 261                 case IRQ_NUBUS_A:
 262                 case IRQ_NUBUS_B:
 263                 case IRQ_NUBUS_C:
 264                 case IRQ_NUBUS_D:
 265                 case IRQ_NUBUS_E:
 266                         irq -= NUBUS_SOURCE_BASE;
 267                         oss->irq_pending &= ~(1 << irq);
 268                         break;
 269         }
 270 }
 271
 272 /*
 273  * Check to see if a specific OSS interrupt is pending
 274  */
 275
 276 int oss_irq_pending(int irq)
 277 {
 278         switch(irq) {
 279                 case IRQ_SCC:
 280                 case IRQ_SCCA:
 281                 case IRQ_SCCB:
 282                         return oss->irq_pending & OSS_IP_IOPSCC;
 283                         break;
 284                 case IRQ_MAC_ADB:
 285                         return oss->irq_pending & OSS_IP_IOPISM;
 286                         break;
 287                 case IRQ_MAC_SCSI:
 288                         return oss->irq_pending & OSS_IP_SCSI;
 289                         break;
 290                 case IRQ_NUBUS_9:
 291                 case IRQ_NUBUS_A:
 292                 case IRQ_NUBUS_B:
 293                 case IRQ_NUBUS_C:
 294                 case IRQ_NUBUS_D:
 295                 case IRQ_NUBUS_E:
 296                         irq -= NUBUS_SOURCE_BASE;
 297                         return oss->irq_pending & (1 << irq);
 298                         break;
 299         }
 300         return 0;
 301 }