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 #ifdef CONFIG_GENERIC_HARDIRQS
  23 #include <linux/irq.h>
  24 #endif
  25
  26 #include <asm/bootinfo.h>
  27 #include <asm/macintosh.h>
  28 #include <asm/macints.h>
  29 #include <asm/mac_via.h>
  30 #include <asm/mac_oss.h>
  31
  32 int oss_present;
  33 volatile struct mac_oss *oss;
  34
  35 static irqreturn_t oss_irq(int, void *);
  36 static irqreturn_t oss_nubus_irq(int, void *);
  37
  38 extern irqreturn_t via1_irq(int, void *);
  39
  40 /*
  41  * Initialize the OSS
  42  *
  43  * The OSS "detection" code is actually in via_init() which is always called
  44  * before us. Thus we can count on oss_present being valid on entry.
  45  */
  46
  47 void __init oss_init(void)
  48 {
  49         int i;
  50
  51         if (!oss_present) return;
  52
  53         oss = (struct mac_oss *) OSS_BASE;
  54
  55         /* Disable all interrupts. Unlike a VIA it looks like we    */
  56         /* do this by setting the source's interrupt level to zero. */
  57
  58         for (i = 0; i <= OSS_NUM_SOURCES; i++) {
  59                 oss->irq_level[i] = OSS_IRQLEV_DISABLED;
  60         }
  61         /* If we disable VIA1 here, we never really handle it... */
  62         oss->irq_level[OSS_VIA1] = OSS_IRQLEV_VIA1;
  63 }
  64
  65 /*
  66  * Register the OSS and NuBus interrupt dispatchers.
  67  */
  68
  69 void __init oss_register_interrupts(void)
  70 {
  71         if (request_irq(OSS_IRQLEV_SCSI, oss_irq, 0, "scsi", (void *)oss))
  72                 pr_err("Couldn't register %s interrupt\n", "scsi");
  73         if (request_irq(OSS_IRQLEV_NUBUS, oss_nubus_irq, 0, "nubus",
  74                         (void *)oss))
  75                 pr_err("Couldn't register %s interrupt\n", "nubus");
  76         if (request_irq(OSS_IRQLEV_SOUND, oss_irq, 0, "sound", (void *)oss))
  77                 pr_err("Couldn't register %s interrupt\n", "sound");
  78         if (request_irq(OSS_IRQLEV_VIA1, via1_irq, 0, "via1", (void *)via1))
  79                 pr_err("Couldn't register %s interrupt\n", "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                 generic_handle_irq(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                         generic_handle_irq(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_MAC_SCC:
 172                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
 173                         break;
 174                 case IRQ_MAC_ADB:
 175                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
 176                         break;
 177                 case IRQ_MAC_SCSI:
 178                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
 179                         break;
 180                 case IRQ_NUBUS_9:
 181                 case IRQ_NUBUS_A:
 182                 case IRQ_NUBUS_B:
 183                 case IRQ_NUBUS_C:
 184                 case IRQ_NUBUS_D:
 185                 case IRQ_NUBUS_E:
 186                         irq -= NUBUS_SOURCE_BASE;
 187                         oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
 188                         break;
 189 #ifdef DEBUG_IRQUSE
 190                 default:
 191                         printk("%s unknown irq %d\n", __func__, irq);
 192                         break;
 193 #endif
 194         }
 195 }
 196
 197 /*
 198  * Disable an OSS interrupt
 199  *
 200  * Same as above except we set the source's interrupt level to zero,
 201  * to disable the interrupt.
 202  */
 203
 204 void oss_irq_disable(int irq) {
 205 #ifdef DEBUG_IRQUSE
 206         printk("oss_irq_disable(%d)\n", irq);
 207 #endif
 208         switch(irq) {
 209                 case IRQ_MAC_SCC:
 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", __func__, 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_MAC_SCC:
 246                         oss->irq_pending &= ~OSS_IP_IOPSCC;
 247                         break;
 248                 case IRQ_MAC_ADB:
 249                         oss->irq_pending &= ~OSS_IP_IOPISM;
 250                         break;
 251                 case IRQ_MAC_SCSI:
 252                         oss->irq_pending &= ~OSS_IP_SCSI;
 253                         break;
 254                 case IRQ_NUBUS_9:
 255                 case IRQ_NUBUS_A:
 256                 case IRQ_NUBUS_B:
 257                 case IRQ_NUBUS_C:
 258                 case IRQ_NUBUS_D:
 259                 case IRQ_NUBUS_E:
 260                         irq -= NUBUS_SOURCE_BASE;
 261                         oss->irq_pending &= ~(1 << irq);
 262                         break;
 263         }
 264 }
 265
 266 /*
 267  * Check to see if a specific OSS interrupt is pending
 268  */
 269
 270 int oss_irq_pending(int irq)
 271 {
 272         switch(irq) {
 273                 case IRQ_MAC_SCC:
 274                         return oss->irq_pending & OSS_IP_IOPSCC;
 275                         break;
 276                 case IRQ_MAC_ADB:
 277                         return oss->irq_pending & OSS_IP_IOPISM;
 278                         break;
 279                 case IRQ_MAC_SCSI:
 280                         return oss->irq_pending & OSS_IP_SCSI;
 281                         break;
 282                 case IRQ_NUBUS_9:
 283                 case IRQ_NUBUS_A:
 284                 case IRQ_NUBUS_B:
 285                 case IRQ_NUBUS_C:
 286                 case IRQ_NUBUS_D:
 287                 case IRQ_NUBUS_E:
 288                         irq -= NUBUS_SOURCE_BASE;
 289                         return oss->irq_pending & (1 << irq);
 290                         break;
 291         }
 292         return 0;
 293 }