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 fulll 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 void oss_irq(int, void *, struct pt_regs *);
  34 void oss_nubus_irq(int, void *, struct pt_regs *);
  35
  36 extern void via1_irq(int, void *, struct pt_regs *);
  37 extern void mac_scc_dispatch(int, void *, struct pt_regs *);
  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         sys_request_irq(OSS_IRQLEV_SCSI, oss_irq, IRQ_FLG_LOCK,
  71                         "scsi", (void *) oss);
  72         sys_request_irq(OSS_IRQLEV_IOPSCC, mac_scc_dispatch, IRQ_FLG_LOCK,
  73                         "scc", mac_scc_dispatch);
  74         sys_request_irq(OSS_IRQLEV_NUBUS, oss_nubus_irq, IRQ_FLG_LOCK,
  75                         "nubus", (void *) oss);
  76         sys_request_irq(OSS_IRQLEV_SOUND, oss_irq, IRQ_FLG_LOCK,
  77                         "sound", (void *) oss);
  78         sys_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 void oss_irq(int irq, void *dev_id, struct pt_regs *regs)
  96 {
  97         int events;
  98
  99         events = oss->irq_pending & (OSS_IP_SOUND|OSS_IP_SCSI);
 100         if (!events) return;
 101
 102 #ifdef DEBUG_IRQS
 103         if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
 104                 printk("oss_irq: irq %d events = 0x%04X\n", irq,
 105                         (int) oss->irq_pending);
 106         }
 107 #endif
 108         /* FIXME: how do you clear a pending IRQ?    */
 109
 110         if (events & OSS_IP_SOUND) {
 111                 /* FIXME: call sound handler */
 112                 oss->irq_pending &= ~OSS_IP_SOUND;
 113         } else if (events & OSS_IP_SCSI) {
 114                 oss->irq_level[OSS_SCSI] = OSS_IRQLEV_DISABLED;
 115                 mac_do_irq_list(IRQ_MAC_SCSI, regs);
 116                 oss->irq_pending &= ~OSS_IP_SCSI;
 117                 oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
 118         } else {
 119                 /* FIXME: error check here? */
 120         }
 121 }
 122
 123 /*
 124  * Nubus IRQ handler, OSS style
 125  *
 126  * Unlike the VIA/RBV this is on its own autovector interupt level.
 127  */
 128
 129 void oss_nubus_irq(int irq, void *dev_id, struct pt_regs *regs)
 130 {
 131         int events, irq_bit, i;
 132
 133         events = oss->irq_pending & OSS_IP_NUBUS;
 134         if (!events) return;
 135
 136 #ifdef DEBUG_NUBUS_INT
 137         if (console_loglevel > 7) {
 138                 printk("oss_nubus_irq: events = 0x%04X\n", events);
 139         }
 140 #endif
 141         /* There are only six slots on the OSS, not seven */
 142
 143         for (i = 0, irq_bit = 1 ; i < 6 ; i++, irq_bit <<= 1) {
 144                 if (events & irq_bit) {
 145                         oss->irq_level[i] = OSS_IRQLEV_DISABLED;
 146                         mac_do_irq_list(NUBUS_SOURCE_BASE + i, regs);
 147                         oss->irq_pending &= ~irq_bit;
 148                         oss->irq_level[i] = OSS_IRQLEV_NUBUS;
 149                 }
 150         }
 151 }
 152
 153 /*
 154  * Enable an OSS interrupt
 155  *
 156  * It looks messy but it's rather straightforward. The switch() statement
 157  * just maps the machspec interrupt numbers to the right OSS interrupt
 158  * source (if the OSS handles that interrupt) and then sets the interrupt
 159  * level for that source to nonzero, thus enabling the interrupt.
 160  */
 161
 162 void oss_irq_enable(int irq) {
 163 #ifdef DEBUG_IRQUSE
 164         printk("oss_irq_enable(%d)\n", irq);
 165 #endif
 166         switch(irq) {
 167                 case IRQ_SCC:
 168                 case IRQ_SCCA:
 169                 case IRQ_SCCB:
 170                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
 171                         break;
 172                 case IRQ_MAC_ADB:
 173                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
 174                         break;
 175                 case IRQ_MAC_SCSI:
 176                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
 177                         break;
 178                 case IRQ_NUBUS_9:
 179                 case IRQ_NUBUS_A:
 180                 case IRQ_NUBUS_B:
 181                 case IRQ_NUBUS_C:
 182                 case IRQ_NUBUS_D:
 183                 case IRQ_NUBUS_E:
 184                         irq -= NUBUS_SOURCE_BASE;
 185                         oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
 186                         break;
 187 #ifdef DEBUG_IRQUSE
 188                 default:
 189                         printk("%s unknown irq %d\n",__FUNCTION__, irq);
 190                         break;
 191 #endif
 192         }
 193 }
 194
 195 /*
 196  * Disable an OSS interrupt
 197  *
 198  * Same as above except we set the source's interrupt level to zero,
 199  * to disable the interrupt.
 200  */
 201
 202 void oss_irq_disable(int irq) {
 203 #ifdef DEBUG_IRQUSE
 204         printk("oss_irq_disable(%d)\n", irq);
 205 #endif
 206         switch(irq) {
 207                 case IRQ_SCC:
 208                 case IRQ_SCCA:
 209                 case IRQ_SCCB:
 210                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_DISABLED;
 211                         break;
 212                 case IRQ_MAC_ADB:
 213                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_DISABLED;
 214                         break;
 215                 case IRQ_MAC_SCSI:
 216                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_DISABLED;
 217                         break;
 218                 case IRQ_NUBUS_9:
 219                 case IRQ_NUBUS_A:
 220                 case IRQ_NUBUS_B:
 221                 case IRQ_NUBUS_C:
 222                 case IRQ_NUBUS_D:
 223                 case IRQ_NUBUS_E:
 224                         irq -= NUBUS_SOURCE_BASE;
 225                         oss->irq_level[irq] = OSS_IRQLEV_DISABLED;
 226                         break;
 227 #ifdef DEBUG_IRQUSE
 228                 default:
 229                         printk("%s unknown irq %d\n", __FUNCTION__, irq);
 230                         break;
 231 #endif
 232         }
 233 }
 234
 235 /*
 236  * Clear an OSS interrupt
 237  *
 238  * Not sure if this works or not but it's the only method I could
 239  * think of based on the contents of the mac_oss structure.
 240  */
 241
 242 void oss_irq_clear(int irq) {
 243         /* FIXME: how to do this on OSS? */
 244         switch(irq) {
 245                 case IRQ_SCC:
 246                 case IRQ_SCCA:
 247                 case IRQ_SCCB:
 248                         oss->irq_pending &= ~OSS_IP_IOPSCC;
 249                         break;
 250                 case IRQ_MAC_ADB:
 251                         oss->irq_pending &= ~OSS_IP_IOPISM;
 252                         break;
 253                 case IRQ_MAC_SCSI:
 254                         oss->irq_pending &= ~OSS_IP_SCSI;
 255                         break;
 256                 case IRQ_NUBUS_9:
 257                 case IRQ_NUBUS_A:
 258                 case IRQ_NUBUS_B:
 259                 case IRQ_NUBUS_C:
 260                 case IRQ_NUBUS_D:
 261                 case IRQ_NUBUS_E:
 262                         irq -= NUBUS_SOURCE_BASE;
 263                         oss->irq_pending &= ~(1 << irq);
 264                         break;
 265         }
 266 }
 267
 268 /*
 269  * Check to see if a specific OSS interrupt is pending
 270  */
 271
 272 int oss_irq_pending(int irq)
 273 {
 274         switch(irq) {
 275                 case IRQ_SCC:
 276                 case IRQ_SCCA:
 277                 case IRQ_SCCB:
 278                         return oss->irq_pending & OSS_IP_IOPSCC;
 279                         break;
 280                 case IRQ_MAC_ADB:
 281                         return oss->irq_pending & OSS_IP_IOPISM;
 282                         break;
 283                 case IRQ_MAC_SCSI:
 284                         return oss->irq_pending & OSS_IP_SCSI;
 285                         break;
 286                 case IRQ_NUBUS_9:
 287                 case IRQ_NUBUS_A:
 288                 case IRQ_NUBUS_B:
 289                 case IRQ_NUBUS_C:
 290                 case IRQ_NUBUS_D:
 291                 case IRQ_NUBUS_E:
 292                         irq -= NUBUS_SOURCE_BASE;
 293                         return oss->irq_pending & (1 << irq);
 294                         break;
 295         }
 296         return 0;
 297 }