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 #include <linux/irq.h>
  23
  24 #include <asm/bootinfo.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 extern void via1_irq(unsigned int irq, struct irq_desc *desc);
  34
  35 /*
  36  * Initialize the OSS
  37  *
  38  * The OSS "detection" code is actually in via_init() which is always called
  39  * before us. Thus we can count on oss_present being valid on entry.
  40  */
  41
  42 void __init oss_init(void)
  43 {
  44         int i;
  45
  46         if (!oss_present) return;
  47
  48         oss = (struct mac_oss *) OSS_BASE;
  49
  50         /* Disable all interrupts. Unlike a VIA it looks like we    */
  51         /* do this by setting the source's interrupt level to zero. */
  52
  53         for (i = 0; i <= OSS_NUM_SOURCES; i++) {
  54                 oss->irq_level[i] = OSS_IRQLEV_DISABLED;
  55         }
  56         /* If we disable VIA1 here, we never really handle it... */
  57         oss->irq_level[OSS_VIA1] = OSS_IRQLEV_VIA1;
  58 }
  59
  60 /*
  61  * Initialize OSS for Nubus access
  62  */
  63
  64 void __init oss_nubus_init(void)
  65 {
  66 }
  67
  68 /*
  69  * Handle miscellaneous OSS interrupts. Right now that's just sound
  70  * and SCSI; everything else is routed to its own autovector IRQ.
  71  */
  72
  73 static void oss_irq(unsigned int irq, struct irq_desc *desc)
  74 {
  75         int events;
  76
  77         events = oss->irq_pending & (OSS_IP_SOUND|OSS_IP_SCSI);
  78         if (!events)
  79                 return;
  80
  81 #ifdef DEBUG_IRQS
  82         if ((console_loglevel == 10) && !(events & OSS_IP_SCSI)) {
  83                 printk("oss_irq: irq %u events = 0x%04X\n", irq,
  84                         (int) oss->irq_pending);
  85         }
  86 #endif
  87         /* FIXME: how do you clear a pending IRQ?    */
  88
  89         if (events & OSS_IP_SOUND) {
  90                 oss->irq_pending &= ~OSS_IP_SOUND;
  91                 /* FIXME: call sound handler */
  92         } else if (events & OSS_IP_SCSI) {
  93                 oss->irq_pending &= ~OSS_IP_SCSI;
  94                 generic_handle_irq(IRQ_MAC_SCSI);
  95         } else {
  96                 /* FIXME: error check here? */
  97         }
  98 }
  99
 100 /*
 101  * Nubus IRQ handler, OSS style
 102  *
 103  * Unlike the VIA/RBV this is on its own autovector interrupt level.
 104  */
 105
 106 static void oss_nubus_irq(unsigned int irq, struct irq_desc *desc)
 107 {
 108         int events, irq_bit, i;
 109
 110         events = oss->irq_pending & OSS_IP_NUBUS;
 111         if (!events)
 112                 return;
 113
 114 #ifdef DEBUG_NUBUS_INT
 115         if (console_loglevel > 7) {
 116                 printk("oss_nubus_irq: events = 0x%04X\n", events);
 117         }
 118 #endif
 119         /* There are only six slots on the OSS, not seven */
 120
 121         i = 6;
 122         irq_bit = 0x40;
 123         do {
 124                 --i;
 125                 irq_bit >>= 1;
 126                 if (events & irq_bit) {
 127                         oss->irq_pending &= ~irq_bit;
 128                         generic_handle_irq(NUBUS_SOURCE_BASE + i);
 129                 }
 130         } while(events & (irq_bit - 1));
 131 }
 132
 133 /*
 134  * Register the OSS and NuBus interrupt dispatchers.
 135  */
 136
 137 void __init oss_register_interrupts(void)
 138 {
 139         irq_set_chained_handler(OSS_IRQLEV_SCSI, oss_irq);
 140         irq_set_chained_handler(OSS_IRQLEV_NUBUS, oss_nubus_irq);
 141         irq_set_chained_handler(OSS_IRQLEV_SOUND, oss_irq);
 142         irq_set_chained_handler(OSS_IRQLEV_VIA1, via1_irq);
 143 }
 144
 145 /*
 146  * Enable an OSS interrupt
 147  *
 148  * It looks messy but it's rather straightforward. The switch() statement
 149  * just maps the machspec interrupt numbers to the right OSS interrupt
 150  * source (if the OSS handles that interrupt) and then sets the interrupt
 151  * level for that source to nonzero, thus enabling the interrupt.
 152  */
 153
 154 void oss_irq_enable(int irq) {
 155 #ifdef DEBUG_IRQUSE
 156         printk("oss_irq_enable(%d)\n", irq);
 157 #endif
 158         switch(irq) {
 159                 case IRQ_MAC_SCC:
 160                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_IOPSCC;
 161                         break;
 162                 case IRQ_MAC_ADB:
 163                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_IOPISM;
 164                         break;
 165                 case IRQ_MAC_SCSI:
 166                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_SCSI;
 167                         break;
 168                 case IRQ_NUBUS_9:
 169                 case IRQ_NUBUS_A:
 170                 case IRQ_NUBUS_B:
 171                 case IRQ_NUBUS_C:
 172                 case IRQ_NUBUS_D:
 173                 case IRQ_NUBUS_E:
 174                         irq -= NUBUS_SOURCE_BASE;
 175                         oss->irq_level[irq] = OSS_IRQLEV_NUBUS;
 176                         break;
 177 #ifdef DEBUG_IRQUSE
 178                 default:
 179                         printk("%s unknown irq %d\n", __func__, irq);
 180                         break;
 181 #endif
 182         }
 183 }
 184
 185 /*
 186  * Disable an OSS interrupt
 187  *
 188  * Same as above except we set the source's interrupt level to zero,
 189  * to disable the interrupt.
 190  */
 191
 192 void oss_irq_disable(int irq) {
 193 #ifdef DEBUG_IRQUSE
 194         printk("oss_irq_disable(%d)\n", irq);
 195 #endif
 196         switch(irq) {
 197                 case IRQ_MAC_SCC:
 198                         oss->irq_level[OSS_IOPSCC] = OSS_IRQLEV_DISABLED;
 199                         break;
 200                 case IRQ_MAC_ADB:
 201                         oss->irq_level[OSS_IOPISM] = OSS_IRQLEV_DISABLED;
 202                         break;
 203                 case IRQ_MAC_SCSI:
 204                         oss->irq_level[OSS_SCSI] = OSS_IRQLEV_DISABLED;
 205                         break;
 206                 case IRQ_NUBUS_9:
 207                 case IRQ_NUBUS_A:
 208                 case IRQ_NUBUS_B:
 209                 case IRQ_NUBUS_C:
 210                 case IRQ_NUBUS_D:
 211                 case IRQ_NUBUS_E:
 212                         irq -= NUBUS_SOURCE_BASE;
 213                         oss->irq_level[irq] = OSS_IRQLEV_DISABLED;
 214                         break;
 215 #ifdef DEBUG_IRQUSE
 216                 default:
 217                         printk("%s unknown irq %d\n", __func__, irq);
 218                         break;
 219 #endif
 220         }
 221 }
 222
 223 /*
 224  * Clear an OSS interrupt
 225  *
 226  * Not sure if this works or not but it's the only method I could
 227  * think of based on the contents of the mac_oss structure.
 228  */
 229
 230 void oss_irq_clear(int irq) {
 231         /* FIXME: how to do this on OSS? */
 232         switch(irq) {
 233                 case IRQ_MAC_SCC:
 234                         oss->irq_pending &= ~OSS_IP_IOPSCC;
 235                         break;
 236                 case IRQ_MAC_ADB:
 237                         oss->irq_pending &= ~OSS_IP_IOPISM;
 238                         break;
 239                 case IRQ_MAC_SCSI:
 240                         oss->irq_pending &= ~OSS_IP_SCSI;
 241                         break;
 242                 case IRQ_NUBUS_9:
 243                 case IRQ_NUBUS_A:
 244                 case IRQ_NUBUS_B:
 245                 case IRQ_NUBUS_C:
 246                 case IRQ_NUBUS_D:
 247                 case IRQ_NUBUS_E:
 248                         irq -= NUBUS_SOURCE_BASE;
 249                         oss->irq_pending &= ~(1 << irq);
 250                         break;
 251         }
 252 }
 253
 254 /*
 255  * Check to see if a specific OSS interrupt is pending
 256  */
 257
 258 int oss_irq_pending(int irq)
 259 {
 260         switch(irq) {
 261                 case IRQ_MAC_SCC:
 262                         return oss->irq_pending & OSS_IP_IOPSCC;
 263                         break;
 264                 case IRQ_MAC_ADB:
 265                         return oss->irq_pending & OSS_IP_IOPISM;
 266                         break;
 267                 case IRQ_MAC_SCSI:
 268                         return oss->irq_pending & OSS_IP_SCSI;
 269                         break;
 270                 case IRQ_NUBUS_9:
 271                 case IRQ_NUBUS_A:
 272                 case IRQ_NUBUS_B:
 273                 case IRQ_NUBUS_C:
 274                 case IRQ_NUBUS_D:
 275                 case IRQ_NUBUS_E:
 276                         irq -= NUBUS_SOURCE_BASE;
 277                         return oss->irq_pending & (1 << irq);
 278                         break;
 279         }
 280         return 0;
 281 }