arch/i386/kernel/visws_apic.c

   1 /*
   2  *      linux/arch/i386/kernel/visws_apic.c
   3  *
   4  *      Copyright (C) 1999 Bent Hagemark, Ingo Molnar
   5  *
   6  *  SGI Visual Workstation interrupt controller
   7  *
   8  *  The Cobalt system ASIC in the Visual Workstation contains a "Cobalt" APIC
   9  *  which serves as the main interrupt controller in the system.  Non-legacy
  10  *  hardware in the system uses this controller directly.  Legacy devices
  11  *  are connected to the PIIX4 which in turn has its 8259(s) connected to
  12  *  a of the Cobalt APIC entry.
  13  */
  14
  15 #include <linux/ptrace.h>
  16 #include <linux/errno.h>
  17 #include <linux/kernel_stat.h>
  18 #include <linux/signal.h>
  19 #include <linux/sched.h>
  20 #include <linux/ioport.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/timex.h>
  23 #include <linux/slab.h>
  24 #include <linux/random.h>
  25 #include <linux/smp.h>
  26 #include <linux/smp_lock.h>
  27 #include <linux/init.h>
  28
  29 #include <asm/system.h>
  30 #include <asm/io.h>
  31 #include <asm/irq.h>
  32 #include <asm/bitops.h>
  33 #include <asm/smp.h>
  34 #include <asm/pgtable.h>
  35 #include <asm/delay.h>
  36 #include <asm/desc.h>
  37
  38 #include <asm/cobalt.h>
  39
  40 #include <linux/irq.h>
  41
  42 /*
  43  * This is the PIIX4-based 8259 that is wired up indirectly to Cobalt
  44  * -- not the manner expected by the normal 8259 code in irq.c.
  45  *
  46  * there is a 'master' physical interrupt source that gets sent to
  47  * the CPU. But in the chipset there are various 'virtual' interrupts
  48  * waiting to be handled. We represent this to Linux through a 'master'
  49  * interrupt controller type, and through a special virtual interrupt-
  50  * controller. Device drivers only see the virtual interrupt sources.
  51  */
  52
  53 #define CO_IRQ_BASE     0x20    /* This is the 0x20 in init_IRQ()! */
  54
  55 static void startup_piix4_master_irq(unsigned int irq);
  56 static void shutdown_piix4_master_irq(unsigned int irq);
  57 static void do_piix4_master_IRQ(unsigned int irq, struct pt_regs * regs);
  58 #define enable_piix4_master_irq startup_piix4_master_irq
  59 #define disable_piix4_master_irq shutdown_piix4_master_irq
  60
  61 static struct hw_interrupt_type piix4_master_irq_type = {
  62         "PIIX4-master",
  63         startup_piix4_master_irq,
  64         shutdown_piix4_master_irq,
  65         do_piix4_master_IRQ,
  66         enable_piix4_master_irq,
  67         disable_piix4_master_irq
  68 };
  69
  70 static void enable_piix4_virtual_irq(unsigned int irq);
  71 static void disable_piix4_virtual_irq(unsigned int irq);
  72 #define startup_piix4_virtual_irq enable_piix4_virtual_irq
  73 #define shutdown_piix4_virtual_irq disable_piix4_virtual_irq
  74
  75 static struct hw_interrupt_type piix4_virtual_irq_type = {
  76         "PIIX4-virtual",
  77         startup_piix4_virtual_irq,
  78         shutdown_piix4_virtual_irq,
  79         0, /* no handler, it's never called physically */
  80         enable_piix4_virtual_irq,
  81         disable_piix4_virtual_irq
  82 };
  83
  84 /*
  85  * This is the SGI Cobalt (IO-)APIC:
  86  */
  87
  88 static void do_cobalt_IRQ(unsigned int irq, struct pt_regs * regs);
  89 static void enable_cobalt_irq(unsigned int irq);
  90 static void disable_cobalt_irq(unsigned int irq);
  91 static void startup_cobalt_irq(unsigned int irq);
  92 #define shutdown_cobalt_irq disable_cobalt_irq
  93
  94 static spinlock_t irq_controller_lock = SPIN_LOCK_UNLOCKED;
  95
  96 static struct hw_interrupt_type cobalt_irq_type = {
  97         "Cobalt-APIC",
  98         startup_cobalt_irq,
  99         shutdown_cobalt_irq,
 100         do_cobalt_IRQ,
 101         enable_cobalt_irq,
 102         disable_cobalt_irq
 103 };
 104
 105
 106 /*
 107  * Not an __init, needed by the reboot code
 108  */
 109 void disable_IO_APIC(void)
 110 {
 111         /* Nop on Cobalt */
 112 }
 113
 114 /*
 115  * Cobalt (IO)-APIC functions to handle PCI devices.
 116  */
 117
 118 static void disable_cobalt_irq(unsigned int irq)
 119 {
 120         /* XXX undo the APIC entry here? */
 121
 122         /*
 123          * definitely, we do not want to have IRQ storms from
 124          * unused devices --mingo
 125          */
 126 }
 127
 128 static void enable_cobalt_irq(unsigned int irq)
 129 {
 130 }
 131
 132 /*
 133  * Set the given Cobalt APIC Redirection Table entry to point
 134  * to the given IDT vector/index.
 135  */
 136 static void co_apic_set(int entry, int idtvec)
 137 {
 138         co_apic_write(CO_APIC_LO(entry), CO_APIC_LEVEL | (CO_IRQ_BASE+idtvec));
 139         co_apic_write(CO_APIC_HI(entry), 0);
 140
 141         printk("Cobalt APIC Entry %d IDT Vector %d\n", entry, idtvec);
 142 }
 143
 144 /*
 145  * "irq" really just serves to identify the device.  Here is where we
 146  * map this to the Cobalt APIC entry where it's physically wired.
 147  * This is called via request_irq -> setup_x86_irq -> irq_desc->startup()
 148  */
 149 static void startup_cobalt_irq(unsigned int irq)
 150 {
 151         /*
 152          * These "irq"'s are wired to the same Cobalt APIC entries
 153          * for all (known) motherboard types/revs
 154          */
 155         switch (irq) {
 156         case CO_IRQ_TIMER:      co_apic_set(CO_APIC_CPU, CO_IRQ_TIMER);
 157                                 return;
 158
 159         case CO_IRQ_ENET:       co_apic_set(CO_APIC_ENET, CO_IRQ_ENET);
 160                                 return;
 161
 162         case CO_IRQ_SERIAL:     return; /* XXX move to piix4-8259 "virtual" */
 163
 164         case CO_IRQ_8259:       co_apic_set(CO_APIC_8259, CO_IRQ_8259);
 165                                 return;
 166
 167         case CO_IRQ_IDE:
 168                 switch (visws_board_type) {
 169                 case VISWS_320:
 170                         switch (visws_board_rev) {
 171                         case 5:
 172                                 co_apic_set(CO_APIC_0_5_IDE0, CO_IRQ_IDE);
 173                                 co_apic_set(CO_APIC_0_5_IDE1, CO_IRQ_IDE);
 174                                         return;
 175                         case 6:
 176                                 co_apic_set(CO_APIC_0_6_IDE0, CO_IRQ_IDE);
 177                                 co_apic_set(CO_APIC_0_6_IDE1, CO_IRQ_IDE);
 178                                         return;
 179                         }
 180                 case VISWS_540:
 181                         switch (visws_board_rev) {
 182                         case 2:
 183                                 co_apic_set(CO_APIC_1_2_IDE0, CO_IRQ_IDE);
 184                                         return;
 185                         }
 186                 }
 187                 break;
 188         default:
 189                 panic("huh?");
 190         }
 191 }
 192
 193 /*
 194  * This is the handle() op in do_IRQ()
 195  */
 196 static void do_cobalt_IRQ(unsigned int irq, struct pt_regs * regs)
 197 {
 198         struct irqaction * action;
 199         irq_desc_t *desc = irq_desc + irq;
 200
 201         spin_lock(&irq_controller_lock);
 202         {
 203                 unsigned int status;
 204                 /* XXX APIC EOI? */
 205                 status = desc->status & ~(IRQ_REPLAY | IRQ_WAITING);
 206                 action = NULL;
 207                 if (!(status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 208                         action = desc->action;
 209                         status |= IRQ_INPROGRESS;
 210                 }
 211                 desc->status = status;
 212         }
 213         spin_unlock(&irq_controller_lock);
 214
 215         /* Exit early if we had no action or it was disabled */
 216         if (!action)
 217                 return;
 218
 219         handle_IRQ_event(irq, regs, action);
 220
 221         (void)co_cpu_read(CO_CPU_REV); /* Sync driver ack to its h/w */
 222         apic_write(APIC_EOI, APIC_EIO_ACK); /* Send EOI to Cobalt APIC */
 223
 224         spin_lock(&irq_controller_lock);
 225         {
 226                 unsigned int status = desc->status & ~IRQ_INPROGRESS;
 227                 desc->status = status;
 228                 if (!(status & IRQ_DISABLED))
 229                         enable_cobalt_irq(irq);
 230         }
 231         spin_unlock(&irq_controller_lock);
 232 }
 233
 234 /*
 235  * PIIX4-8259 master/virtual functions to handle:
 236  *
 237  *      floppy
 238  *      parallel
 239  *      serial
 240  *      audio (?)
 241  *
 242  * None of these get Cobalt APIC entries, neither do they have IDT
 243  * entries. These interrupts are purely virtual and distributed from
 244  * the 'master' interrupt source: CO_IRQ_8259.
 245  *
 246  * When the 8259 interrupts its handler figures out which of these
 247  * devices is interrupting and dispatches to it's handler.
 248  *
 249  * CAREFUL: devices see the 'virtual' interrupt only. Thus disable/
 250  * enable_irq gets the right irq. This 'master' irq is never directly
 251  * manipulated by any driver.
 252  */
 253
 254 static void startup_piix4_master_irq(unsigned int irq)
 255 {
 256         /* ICW1 */
 257         outb(0x11, 0x20);
 258         outb(0x11, 0xa0);
 259
 260         /* ICW2 */
 261         outb(0x08, 0x21);
 262         outb(0x70, 0xa1);
 263
 264         /* ICW3 */
 265         outb(0x04, 0x21);
 266         outb(0x02, 0xa1);
 267
 268         /* ICW4 */
 269         outb(0x01, 0x21);
 270         outb(0x01, 0xa1);
 271
 272         /* OCW1 - disable all interrupts in both 8259's */
 273         outb(0xff, 0x21);
 274         outb(0xff, 0xa1);
 275
 276         startup_cobalt_irq(irq);
 277 }
 278
 279 static void shutdown_piix4_master_irq(unsigned int irq)
 280 {
 281         /*
 282          * [we skip the 8259 magic here, not strictly necessary]
 283          */
 284
 285         shutdown_cobalt_irq(irq);
 286 }
 287
 288 static void do_piix4_master_IRQ(unsigned int irq, struct pt_regs * regs)
 289 {
 290         int realirq, mask;
 291
 292         /* Find out what's interrupting in the PIIX4 8259 */
 293
 294         spin_lock(&irq_controller_lock);
 295         outb(0x0c, 0x20);               /* OCW3 Poll command */
 296         realirq = inb(0x20);
 297
 298         if (!(realirq & 0x80)) {
 299                 /*
 300                  * Bit 7 == 0 means invalid/spurious
 301                  */
 302                 goto out_unlock;
 303         }
 304         realirq &= 0x7f;
 305
 306         /*
 307          * mask and ack the 8259
 308          */
 309         mask = inb(0x21);
 310         if ((mask >> realirq) & 0x01)
 311                 /*
 312                  * This IRQ is masked... ignore
 313                  */
 314                 goto out_unlock;
 315
 316         outb(mask | (1<<realirq), 0x21);
 317         /*
 318          * OCW2 - non-specific EOI
 319          */
 320         outb(0x20, 0x20);
 321
 322         spin_unlock(&irq_controller_lock);
 323
 324         /*
 325          * handle this 'virtual interrupt' as a Cobalt one now.
 326          */
 327         kstat.irqs[smp_processor_id()][irq]++;
 328         do_cobalt_IRQ(realirq, regs);
 329
 330         spin_lock(&irq_controller_lock);
 331         {
 332                 irq_desc_t *desc = irq_desc + realirq;
 333
 334                 if (!(desc->status & IRQ_DISABLED))
 335                         enable_piix4_virtual_irq(realirq);
 336         }
 337         spin_unlock(&irq_controller_lock);
 338         return;
 339
 340 out_unlock:
 341         spin_unlock(&irq_controller_lock);
 342         return;
 343 }
 344
 345 static void enable_piix4_virtual_irq(unsigned int irq)
 346 {
 347         /*
 348          * assumes this irq is one of the legacy devices
 349          */
 350
 351         unsigned int mask = inb(0x21);
 352         mask &= ~(1 << irq);
 353         outb(mask, 0x21);
 354         enable_cobalt_irq(irq);
 355 }
 356
 357 /*
 358  * assumes this irq is one of the legacy devices
 359  */
 360 static void disable_piix4_virtual_irq(unsigned int irq)
 361 {
 362         unsigned int mask;
 363
 364         disable_cobalt_irq(irq);
 365
 366         mask = inb(0x21);
 367         mask &= ~(1 << irq);
 368         outb(mask, 0x21);
 369 }
 370
 371 static struct irqaction master_action =
 372                 { no_action, 0, 0, "PIIX4-8259", NULL, NULL };
 373
 374 void init_VISWS_APIC_irqs(void)
 375 {
 376         int i;
 377
 378         for (i = 0; i < 16; i++) {
 379                 irq_desc[i].status = IRQ_DISABLED;
 380                 irq_desc[i].action = 0;
 381                 irq_desc[i].depth = 1;
 382
 383                 /*
 384                  * Cobalt IRQs are mapped to standard ISA
 385                  * interrupt vectors:
 386                  */
 387                 switch (i) {
 388                         /*
 389                          * Only CO_IRQ_8259 will be raised
 390                          * externally.
 391                          */
 392                 case CO_IRQ_8259:
 393                         irq_desc[i].handler = &piix4_master_irq_type;
 394                         break;
 395                 case CO_IRQ_FLOPPY:
 396                 case CO_IRQ_PARLL:
 397                         irq_desc[i].handler = &piix4_virtual_irq_type;
 398                         break;
 399                 default:
 400                         irq_desc[i].handler = &cobalt_irq_type;
 401                         break;
 402                 }
 403         }
 404
 405         /*
 406          * The master interrupt is always present:
 407          */
 408         setup_x86_irq(CO_IRQ_8259, &master_action);
 409 }
 410