git.oblomov.eu Git - linux-2.6/blob - arch/mips/sibyte/bcm1480/irq.c

   1 /*
   2  * Copyright (C) 2000,2001,2002,2003,2004 Broadcom Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; either version 2
   7  * of the License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18 #include <linux/config.h>
  19 #include <linux/kernel.h>
  20 #include <linux/init.h>
  21 #include <linux/linkage.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/spinlock.h>
  24 #include <linux/mm.h>
  25 #include <linux/slab.h>
  26 #include <linux/kernel_stat.h>
  27
  28 #include <asm/errno.h>
  29 #include <asm/signal.h>
  30 #include <asm/system.h>
  31 #include <asm/ptrace.h>
  32 #include <asm/io.h>
  33
  34 #include <asm/sibyte/bcm1480_regs.h>
  35 #include <asm/sibyte/bcm1480_int.h>
  36 #include <asm/sibyte/bcm1480_scd.h>
  37
  38 #include <asm/sibyte/sb1250_uart.h>
  39 #include <asm/sibyte/sb1250.h>
  40
  41 /*
  42  * These are the routines that handle all the low level interrupt stuff.
  43  * Actions handled here are: initialization of the interrupt map, requesting of
  44  * interrupt lines by handlers, dispatching if interrupts to handlers, probing
  45  * for interrupt lines
  46  */
  47
  48
  49 #define shutdown_bcm1480_irq    disable_bcm1480_irq
  50 static void end_bcm1480_irq(unsigned int irq);
  51 static void enable_bcm1480_irq(unsigned int irq);
  52 static void disable_bcm1480_irq(unsigned int irq);
  53 static unsigned int startup_bcm1480_irq(unsigned int irq);
  54 static void ack_bcm1480_irq(unsigned int irq);
  55 #ifdef CONFIG_SMP
  56 static void bcm1480_set_affinity(unsigned int irq, cpumask_t mask);
  57 #endif
  58
  59 #ifdef CONFIG_PCI
  60 extern unsigned long ht_eoi_space;
  61 #endif
  62
  63 #ifdef CONFIG_KGDB
  64 #include <asm/gdb-stub.h>
  65 extern void breakpoint(void);
  66 static int kgdb_irq;
  67 #ifdef CONFIG_GDB_CONSOLE
  68 extern void register_gdb_console(void);
  69 #endif
  70
  71 /* kgdb is on when configured.  Pass "nokgdb" kernel arg to turn it off */
  72 static int kgdb_flag = 1;
  73 static int __init nokgdb(char *str)
  74 {
  75         kgdb_flag = 0;
  76         return 1;
  77 }
  78 __setup("nokgdb", nokgdb);
  79
  80 /* Default to UART1 */
  81 int kgdb_port = 1;
  82 #ifdef CONFIG_SIBYTE_SB1250_DUART
  83 extern char sb1250_duart_present[];
  84 #endif
  85 #endif
  86
  87 static struct hw_interrupt_type bcm1480_irq_type = {
  88         .typename = "BCM1480-IMR",
  89         .startup = startup_bcm1480_irq,
  90         .shutdown = shutdown_bcm1480_irq,
  91         .enable = enable_bcm1480_irq,
  92         .disable = disable_bcm1480_irq,
  93         .ack = ack_bcm1480_irq,
  94         .end = end_bcm1480_irq,
  95 #ifdef CONFIG_SMP
  96         .set_affinity = bcm1480_set_affinity
  97 #endif
  98 };
  99
 100 /* Store the CPU id (not the logical number) */
 101 int bcm1480_irq_owner[BCM1480_NR_IRQS];
 102
 103 DEFINE_SPINLOCK(bcm1480_imr_lock);
 104
 105 void bcm1480_mask_irq(int cpu, int irq)
 106 {
 107         unsigned long flags;
 108         u64 cur_ints,hl_spacing;
 109
 110         spin_lock_irqsave(&bcm1480_imr_lock, flags);
 111         hl_spacing = 0;
 112         if ((irq >= BCM1480_NR_IRQS_HALF) && (irq <= BCM1480_NR_IRQS)) {
 113                 hl_spacing = BCM1480_IMR_HL_SPACING;
 114                 irq -= BCM1480_NR_IRQS_HALF;
 115         }
 116         cur_ints = ____raw_readq(IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + hl_spacing));
 117         cur_ints |= (((u64) 1) << irq);
 118         ____raw_writeq(cur_ints, IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + hl_spacing));
 119         spin_unlock_irqrestore(&bcm1480_imr_lock, flags);
 120 }
 121
 122 void bcm1480_unmask_irq(int cpu, int irq)
 123 {
 124         unsigned long flags;
 125         u64 cur_ints,hl_spacing;
 126
 127         spin_lock_irqsave(&bcm1480_imr_lock, flags);
 128         hl_spacing = 0;
 129         if ((irq >= BCM1480_NR_IRQS_HALF) && (irq <= BCM1480_NR_IRQS)) {
 130                 hl_spacing = BCM1480_IMR_HL_SPACING;
 131                 irq -= BCM1480_NR_IRQS_HALF;
 132         }
 133         cur_ints = ____raw_readq(IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + hl_spacing));
 134         cur_ints &= ~(((u64) 1) << irq);
 135         ____raw_writeq(cur_ints, IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + hl_spacing));
 136         spin_unlock_irqrestore(&bcm1480_imr_lock, flags);
 137 }
 138
 139 #ifdef CONFIG_SMP
 140 static void bcm1480_set_affinity(unsigned int irq, cpumask_t mask)
 141 {
 142         int i = 0, old_cpu, cpu, int_on, k;
 143         u64 cur_ints;
 144         irq_desc_t *desc = irq_desc + irq;
 145         unsigned long flags;
 146         unsigned int irq_dirty;
 147
 148         i = first_cpu(mask);
 149         if (next_cpu(i, mask) <= NR_CPUS) {
 150                 printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 151                 return;
 152         }
 153
 154         /* Convert logical CPU to physical CPU */
 155         cpu = cpu_logical_map(i);
 156
 157         /* Protect against other affinity changers and IMR manipulation */
 158         spin_lock_irqsave(&desc->lock, flags);
 159         spin_lock(&bcm1480_imr_lock);
 160
 161         /* Swizzle each CPU's IMR (but leave the IP selection alone) */
 162         old_cpu = bcm1480_irq_owner[irq];
 163         irq_dirty = irq;
 164         if ((irq_dirty >= BCM1480_NR_IRQS_HALF) && (irq_dirty <= BCM1480_NR_IRQS)) {
 165                 irq_dirty -= BCM1480_NR_IRQS_HALF;
 166         }
 167
 168         for (k=0; k<2; k++) { /* Loop through high and low interrupt mask register */
 169                 cur_ints = ____raw_readq(IOADDR(A_BCM1480_IMR_MAPPER(old_cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + (k*BCM1480_IMR_HL_SPACING)));
 170                 int_on = !(cur_ints & (((u64) 1) << irq_dirty));
 171                 if (int_on) {
 172                         /* If it was on, mask it */
 173                         cur_ints |= (((u64) 1) << irq_dirty);
 174                         ____raw_writeq(cur_ints, IOADDR(A_BCM1480_IMR_MAPPER(old_cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + (k*BCM1480_IMR_HL_SPACING)));
 175                 }
 176                 bcm1480_irq_owner[irq] = cpu;
 177                 if (int_on) {
 178                         /* unmask for the new CPU */
 179                         cur_ints = ____raw_readq(IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + (k*BCM1480_IMR_HL_SPACING)));
 180                         cur_ints &= ~(((u64) 1) << irq_dirty);
 181                         ____raw_writeq(cur_ints, IOADDR(A_BCM1480_IMR_MAPPER(cpu) + R_BCM1480_IMR_INTERRUPT_MASK_H + (k*BCM1480_IMR_HL_SPACING)));
 182                 }
 183         }
 184         spin_unlock(&bcm1480_imr_lock);
 185         spin_unlock_irqrestore(&desc->lock, flags);
 186 }
 187 #endif
 188
 189
 190 /*****************************************************************************/
 191
 192 static unsigned int startup_bcm1480_irq(unsigned int irq)
 193 {
 194         bcm1480_unmask_irq(bcm1480_irq_owner[irq], irq);
 195
 196         return 0;               /* never anything pending */
 197 }
 198
 199
 200 static void disable_bcm1480_irq(unsigned int irq)
 201 {
 202         bcm1480_mask_irq(bcm1480_irq_owner[irq], irq);
 203 }
 204
 205 static void enable_bcm1480_irq(unsigned int irq)
 206 {
 207         bcm1480_unmask_irq(bcm1480_irq_owner[irq], irq);
 208 }
 209
 210
 211 static void ack_bcm1480_irq(unsigned int irq)
 212 {
 213         u64 pending;
 214         unsigned int irq_dirty;
 215         int k;
 216
 217         /*
 218          * If the interrupt was an HT interrupt, now is the time to
 219          * clear it.  NOTE: we assume the HT bridge was set up to
 220          * deliver the interrupts to all CPUs (which makes affinity
 221          * changing easier for us)
 222          */
 223         irq_dirty = irq;
 224         if ((irq_dirty >= BCM1480_NR_IRQS_HALF) && (irq_dirty <= BCM1480_NR_IRQS)) {
 225                 irq_dirty -= BCM1480_NR_IRQS_HALF;
 226         }
 227         for (k=0; k<2; k++) { /* Loop through high and low LDT interrupts */
 228                 pending = __raw_readq(IOADDR(A_BCM1480_IMR_REGISTER(bcm1480_irq_owner[irq],
 229                                                 R_BCM1480_IMR_LDT_INTERRUPT_H + (k*BCM1480_IMR_HL_SPACING))));
 230                 pending &= ((u64)1 << (irq_dirty));
 231                 if (pending) {
 232 #ifdef CONFIG_SMP
 233                         int i;
 234                         for (i=0; i<NR_CPUS; i++) {
 235                                 /*
 236                                  * Clear for all CPUs so an affinity switch
 237                                  * doesn't find an old status
 238                                  */
 239                                 __raw_writeq(pending, IOADDR(A_BCM1480_IMR_REGISTER(cpu_logical_map(i),
 240                                                                 R_BCM1480_IMR_LDT_INTERRUPT_CLR_H + (k*BCM1480_IMR_HL_SPACING))));
 241                         }
 242 #else
 243                         __raw_writeq(pending, IOADDR(A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_LDT_INTERRUPT_CLR_H + (k*BCM1480_IMR_HL_SPACING))));
 244 #endif
 245
 246                         /*
 247                          * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 248                          * Pass 2, the LDT world may be edge-triggered, but
 249                          * this EOI shouldn't hurt.  If they are
 250                          * level-sensitive, the EOI is required.
 251                          */
 252 #ifdef CONFIG_PCI
 253                         if (ht_eoi_space)
 254                                 *(uint32_t *)(ht_eoi_space+(irq<<16)+(7<<2)) = 0;
 255 #endif
 256                 }
 257         }
 258         bcm1480_mask_irq(bcm1480_irq_owner[irq], irq);
 259 }
 260
 261
 262 static void end_bcm1480_irq(unsigned int irq)
 263 {
 264         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 265                 bcm1480_unmask_irq(bcm1480_irq_owner[irq], irq);
 266         }
 267 }
 268
 269
 270 void __init init_bcm1480_irqs(void)
 271 {
 272         int i;
 273
 274         for (i = 0; i < NR_IRQS; i++) {
 275                 irq_desc[i].status = IRQ_DISABLED;
 276                 irq_desc[i].action = 0;
 277                 irq_desc[i].depth = 1;
 278                 if (i < BCM1480_NR_IRQS) {
 279                         irq_desc[i].handler = &bcm1480_irq_type;
 280                         bcm1480_irq_owner[i] = 0;
 281                 } else {
 282                         irq_desc[i].handler = &no_irq_type;
 283                 }
 284         }
 285 }
 286
 287
 288 static irqreturn_t bcm1480_dummy_handler(int irq, void *dev_id,
 289         struct pt_regs *regs)
 290 {
 291         return IRQ_NONE;
 292 }
 293
 294 static struct irqaction bcm1480_dummy_action = {
 295         .handler = bcm1480_dummy_handler,
 296         .flags   = 0,
 297         .mask    = CPU_MASK_NONE,
 298         .name    = "bcm1480-private",
 299         .next    = NULL,
 300         .dev_id  = 0
 301 };
 302
 303 int bcm1480_steal_irq(int irq)
 304 {
 305         irq_desc_t *desc = irq_desc + irq;
 306         unsigned long flags;
 307         int retval = 0;
 308
 309         if (irq >= BCM1480_NR_IRQS)
 310                 return -EINVAL;
 311
 312         spin_lock_irqsave(&desc->lock,flags);
 313         /* Don't allow sharing at all for these */
 314         if (desc->action != NULL)
 315                 retval = -EBUSY;
 316         else {
 317                 desc->action = &bcm1480_dummy_action;
 318                 desc->depth = 0;
 319         }
 320         spin_unlock_irqrestore(&desc->lock,flags);
 321         return 0;
 322 }
 323
 324 /*
 325  *  init_IRQ is called early in the boot sequence from init/main.c.  It
 326  *  is responsible for setting up the interrupt mapper and installing the
 327  *  handler that will be responsible for dispatching interrupts to the
 328  *  "right" place.
 329  */
 330 /*
 331  * For now, map all interrupts to IP[2].  We could save
 332  * some cycles by parceling out system interrupts to different
 333  * IP lines, but keep it simple for bringup.  We'll also direct
 334  * all interrupts to a single CPU; we should probably route
 335  * PCI and LDT to one cpu and everything else to the other
 336  * to balance the load a bit.
 337  *
 338  * On the second cpu, everything is set to IP5, which is
 339  * ignored, EXCEPT the mailbox interrupt.  That one is
 340  * set to IP[2] so it is handled.  This is needed so we
 341  * can do cross-cpu function calls, as requred by SMP
 342  */
 343
 344 #define IMR_IP2_VAL     K_BCM1480_INT_MAP_I0
 345 #define IMR_IP3_VAL     K_BCM1480_INT_MAP_I1
 346 #define IMR_IP4_VAL     K_BCM1480_INT_MAP_I2
 347 #define IMR_IP5_VAL     K_BCM1480_INT_MAP_I3
 348 #define IMR_IP6_VAL     K_BCM1480_INT_MAP_I4
 349
 350 void __init arch_init_irq(void)
 351 {
 352
 353         unsigned int i, cpu;
 354         u64 tmp;
 355         unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 356                 STATUSF_IP1 | STATUSF_IP0;
 357
 358         /* Default everything to IP2 */
 359         /* Start with _high registers which has no bit 0 interrupt source */
 360         for (i = 1; i < BCM1480_NR_IRQS_HALF; i++) {    /* was I0 */
 361                 for (cpu = 0; cpu < 4; cpu++) {
 362                         __raw_writeq(IMR_IP2_VAL,
 363                                      IOADDR(A_BCM1480_IMR_REGISTER(cpu,
 364                                                                    R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) + (i << 3)));
 365                 }
 366         }
 367
 368         /* Now do _low registers */
 369         for (i = 0; i < BCM1480_NR_IRQS_HALF; i++) {
 370                 for (cpu = 0; cpu < 4; cpu++) {
 371                         __raw_writeq(IMR_IP2_VAL,
 372                                      IOADDR(A_BCM1480_IMR_REGISTER(cpu,
 373                                                                    R_BCM1480_IMR_INTERRUPT_MAP_BASE_L) + (i << 3)));
 374                 }
 375         }
 376
 377         init_bcm1480_irqs();
 378
 379         /*
 380          * Map the high 16 bits of mailbox_0 registers to IP[3], for
 381          * inter-cpu messages
 382          */
 383         /* Was I1 */
 384         for (cpu = 0; cpu < 4; cpu++) {
 385                 __raw_writeq(IMR_IP3_VAL, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) +
 386                                                  (K_BCM1480_INT_MBOX_0_0 << 3)));
 387         }
 388
 389
 390         /* Clear the mailboxes.  The firmware may leave them dirty */
 391         for (cpu = 0; cpu < 4; cpu++) {
 392                 __raw_writeq(0xffffffffffffffffULL,
 393                              IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_MAILBOX_0_CLR_CPU)));
 394                 __raw_writeq(0xffffffffffffffffULL,
 395                              IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_MAILBOX_1_CLR_CPU)));
 396         }
 397
 398
 399         /* Mask everything except the high 16 bit of mailbox_0 registers for all cpus */
 400         tmp = ~((u64) 0) ^ ( (((u64) 1) << K_BCM1480_INT_MBOX_0_0));
 401         for (cpu = 0; cpu < 4; cpu++) {
 402                 __raw_writeq(tmp, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MASK_H)));
 403         }
 404         tmp = ~((u64) 0);
 405         for (cpu = 0; cpu < 4; cpu++) {
 406                 __raw_writeq(tmp, IOADDR(A_BCM1480_IMR_REGISTER(cpu, R_BCM1480_IMR_INTERRUPT_MASK_L)));
 407         }
 408
 409         bcm1480_steal_irq(K_BCM1480_INT_MBOX_0_0);
 410
 411         /*
 412          * Note that the timer interrupts are also mapped, but this is
 413          * done in bcm1480_time_init().  Also, the profiling driver
 414          * does its own management of IP7.
 415          */
 416
 417 #ifdef CONFIG_KGDB
 418         imask |= STATUSF_IP6;
 419 #endif
 420         /* Enable necessary IPs, disable the rest */
 421         change_c0_status(ST0_IM, imask);
 422
 423 #ifdef CONFIG_KGDB
 424         if (kgdb_flag) {
 425                 kgdb_irq = K_BCM1480_INT_UART_0 + kgdb_port;
 426
 427 #ifdef CONFIG_SIBYTE_SB1250_DUART
 428                 sb1250_duart_present[kgdb_port] = 0;
 429 #endif
 430                 /* Setup uart 1 settings, mapper */
 431                 /* QQQ FIXME */
 432                 __raw_writeq(M_DUART_IMR_BRK, IO_SPACE_BASE + A_DUART_IMRREG(kgdb_port));
 433
 434                 bcm1480_steal_irq(kgdb_irq);
 435                 __raw_writeq(IMR_IP6_VAL,
 436                              IO_SPACE_BASE + A_BCM1480_IMR_REGISTER(0, R_BCM1480_IMR_INTERRUPT_MAP_BASE_H) +
 437                              (kgdb_irq<<3));
 438                 bcm1480_unmask_irq(0, kgdb_irq);
 439
 440 #ifdef CONFIG_GDB_CONSOLE
 441                 register_gdb_console();
 442 #endif
 443                 prom_printf("Waiting for GDB on UART port %d\n", kgdb_port);
 444                 set_debug_traps();
 445                 breakpoint();
 446         }
 447 #endif
 448 }
 449
 450 #ifdef CONFIG_KGDB
 451
 452 #include <linux/delay.h>
 453
 454 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 455 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 456
 457 void bcm1480_kgdb_interrupt(struct pt_regs *regs)
 458 {
 459         /*
 460          * Clear break-change status (allow some time for the remote
 461          * host to stop the break, since we would see another
 462          * interrupt on the end-of-break too)
 463          */
 464         kstat.irqs[smp_processor_id()][kgdb_irq]++;
 465         mdelay(500);
 466         duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
 467                                 M_DUART_RX_EN | M_DUART_TX_EN);
 468         set_async_breakpoint(&regs->cp0_epc);
 469 }
 470
 471 #endif  /* CONFIG_KGDB */
 472
 473 static inline int dclz(unsigned long long x)
 474 {
 475         int lz;
 476
 477         __asm__ (
 478         "       .set    push                                            \n"
 479         "       .set    mips64                                          \n"
 480         "       dclz    %0, %1                                          \n"
 481         "       .set    pop                                             \n"
 482         : "=r" (lz)
 483         : "r" (x));
 484
 485         return lz;
 486 }
 487
 488 extern void bcm1480_timer_interrupt(struct pt_regs *regs);
 489 extern void bcm1480_mailbox_interrupt(struct pt_regs *regs);
 490 extern void bcm1480_kgdb_interrupt(struct pt_regs *regs);
 491
 492 asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
 493 {
 494         unsigned int pending;
 495
 496 #ifdef CONFIG_SIBYTE_BCM1480_PROF
 497         /* Set compare to count to silence count/compare timer interrupts */
 498         write_c0_compare(read_c0_count());
 499 #endif
 500
 501         pending = read_c0_cause();
 502
 503 #ifdef CONFIG_SIBYTE_BCM1480_PROF
 504         if (pending & CAUSEF_IP7)       /* Cpu performance counter interrupt */
 505                 sbprof_cpu_intr(exception_epc(regs));
 506 #endif
 507
 508         if (pending & CAUSEF_IP4)
 509                 bcm1480_timer_interrupt(regs);
 510
 511 #ifdef CONFIG_SMP
 512         if (pending & CAUSEF_IP3)
 513                 bcm1480_mailbox_interrupt(regs);
 514 #endif
 515
 516 #ifdef CONFIG_KGDB
 517         if (pending & CAUSEF_IP6)
 518                 bcm1480_kgdb_interrupt(regs);           /* KGDB (uart 1) */
 519 #endif
 520
 521         if (pending & CAUSEF_IP2) {
 522                 unsigned long long mask_h, mask_l;
 523                 unsigned long base;
 524
 525                 /*
 526                  * Default...we've hit an IP[2] interrupt, which means we've
 527                  * got to check the 1480 interrupt registers to figure out what
 528                  * to do.  Need to detect which CPU we're on, now that
 529                  * smp_affinity is supported.
 530                  */
 531                 base = A_BCM1480_IMR_MAPPER(smp_processor_id());
 532                 mask_h = __raw_readq(
 533                         IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_H));
 534                 mask_l = __raw_readq(
 535                         IOADDR(base + R_BCM1480_IMR_INTERRUPT_STATUS_BASE_L));
 536
 537                 if (!mask_h) {
 538                         if (mask_h ^ 1)
 539                                 do_IRQ(63 - dclz(mask_h), regs);
 540                         else
 541                                 do_IRQ(127 - dclz(mask_l), regs);
 542                 }
 543         }
 544 }