arch/mips/sibyte/sb1250/irq.c

   1 /*
   2  * Copyright (C) 2000, 2001, 2002, 2003 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/smp.h>
  25 #include <linux/mm.h>
  26 #include <linux/slab.h>
  27 #include <linux/kernel_stat.h>
  28
  29 #include <asm/errno.h>
  30 #include <asm/signal.h>
  31 #include <asm/system.h>
  32 #include <asm/ptrace.h>
  33 #include <asm/io.h>
  34
  35 #include <asm/sibyte/sb1250_regs.h>
  36 #include <asm/sibyte/sb1250_int.h>
  37 #include <asm/sibyte/sb1250_uart.h>
  38 #include <asm/sibyte/sb1250_scd.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_sb1250_irq     disable_sb1250_irq
  50 static void end_sb1250_irq(unsigned int irq);
  51 static void enable_sb1250_irq(unsigned int irq);
  52 static void disable_sb1250_irq(unsigned int irq);
  53 static unsigned int startup_sb1250_irq(unsigned int irq);
  54 static void ack_sb1250_irq(unsigned int irq);
  55 #ifdef CONFIG_SMP
  56 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
  57 #endif
  58
  59 #ifdef CONFIG_SIBYTE_HAS_LDT
  60 extern unsigned long ldt_eoi_space;
  61 #endif
  62
  63 #ifdef CONFIG_KGDB
  64 static int kgdb_irq;
  65
  66 /* Default to UART1 */
  67 int kgdb_port = 1;
  68 #ifdef CONFIG_SIBYTE_SB1250_DUART
  69 extern char sb1250_duart_present[];
  70 #endif
  71 #endif
  72
  73 static struct hw_interrupt_type sb1250_irq_type = {
  74         .typename = "SB1250-IMR",
  75         .startup = startup_sb1250_irq,
  76         .shutdown = shutdown_sb1250_irq,
  77         .enable = enable_sb1250_irq,
  78         .disable = disable_sb1250_irq,
  79         .ack = ack_sb1250_irq,
  80         .end = end_sb1250_irq,
  81 #ifdef CONFIG_SMP
  82         .set_affinity = sb1250_set_affinity
  83 #endif
  84 };
  85
  86 /* Store the CPU id (not the logical number) */
  87 int sb1250_irq_owner[SB1250_NR_IRQS];
  88
  89 DEFINE_SPINLOCK(sb1250_imr_lock);
  90
  91 void sb1250_mask_irq(int cpu, int irq)
  92 {
  93         unsigned long flags;
  94         u64 cur_ints;
  95
  96         spin_lock_irqsave(&sb1250_imr_lock, flags);
  97         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
  98                                         R_IMR_INTERRUPT_MASK));
  99         cur_ints |= (((u64) 1) << irq);
 100         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 101                                         R_IMR_INTERRUPT_MASK));
 102         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 103 }
 104
 105 void sb1250_unmask_irq(int cpu, int irq)
 106 {
 107         unsigned long flags;
 108         u64 cur_ints;
 109
 110         spin_lock_irqsave(&sb1250_imr_lock, flags);
 111         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 112                                         R_IMR_INTERRUPT_MASK));
 113         cur_ints &= ~(((u64) 1) << irq);
 114         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 115                                         R_IMR_INTERRUPT_MASK));
 116         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 117 }
 118
 119 #ifdef CONFIG_SMP
 120 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 121 {
 122         int i = 0, old_cpu, cpu, int_on;
 123         u64 cur_ints;
 124         irq_desc_t *desc = irq_desc + irq;
 125         unsigned long flags;
 126
 127         i = first_cpu(mask);
 128
 129         if (cpus_weight(mask) > 1) {
 130                 printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 131                 return;
 132         }
 133
 134         /* Convert logical CPU to physical CPU */
 135         cpu = cpu_logical_map(i);
 136
 137         /* Protect against other affinity changers and IMR manipulation */
 138         spin_lock_irqsave(&desc->lock, flags);
 139         spin_lock(&sb1250_imr_lock);
 140
 141         /* Swizzle each CPU's IMR (but leave the IP selection alone) */
 142         old_cpu = sb1250_irq_owner[irq];
 143         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
 144                                         R_IMR_INTERRUPT_MASK));
 145         int_on = !(cur_ints & (((u64) 1) << irq));
 146         if (int_on) {
 147                 /* If it was on, mask it */
 148                 cur_ints |= (((u64) 1) << irq);
 149                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
 150                                         R_IMR_INTERRUPT_MASK));
 151         }
 152         sb1250_irq_owner[irq] = cpu;
 153         if (int_on) {
 154                 /* unmask for the new CPU */
 155                 cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 156                                         R_IMR_INTERRUPT_MASK));
 157                 cur_ints &= ~(((u64) 1) << irq);
 158                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 159                                         R_IMR_INTERRUPT_MASK));
 160         }
 161         spin_unlock(&sb1250_imr_lock);
 162         spin_unlock_irqrestore(&desc->lock, flags);
 163 }
 164 #endif
 165
 166 /*****************************************************************************/
 167
 168 static unsigned int startup_sb1250_irq(unsigned int irq)
 169 {
 170         sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 171
 172         return 0;               /* never anything pending */
 173 }
 174
 175
 176 static void disable_sb1250_irq(unsigned int irq)
 177 {
 178         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 179 }
 180
 181 static void enable_sb1250_irq(unsigned int irq)
 182 {
 183         sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 184 }
 185
 186
 187 static void ack_sb1250_irq(unsigned int irq)
 188 {
 189 #ifdef CONFIG_SIBYTE_HAS_LDT
 190         u64 pending;
 191
 192         /*
 193          * If the interrupt was an HT interrupt, now is the time to
 194          * clear it.  NOTE: we assume the HT bridge was set up to
 195          * deliver the interrupts to all CPUs (which makes affinity
 196          * changing easier for us)
 197          */
 198         pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
 199                                                     R_IMR_LDT_INTERRUPT)));
 200         pending &= ((u64)1 << (irq));
 201         if (pending) {
 202                 int i;
 203                 for (i=0; i<NR_CPUS; i++) {
 204                         int cpu;
 205 #ifdef CONFIG_SMP
 206                         cpu = cpu_logical_map(i);
 207 #else
 208                         cpu = i;
 209 #endif
 210                         /*
 211                          * Clear for all CPUs so an affinity switch
 212                          * doesn't find an old status
 213                          */
 214                         __raw_writeq(pending,
 215                                      IOADDR(A_IMR_REGISTER(cpu,
 216                                                 R_IMR_LDT_INTERRUPT_CLR)));
 217                 }
 218
 219                 /*
 220                  * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 221                  * Pass 2, the LDT world may be edge-triggered, but
 222                  * this EOI shouldn't hurt.  If they are
 223                  * level-sensitive, the EOI is required.
 224                  */
 225                 *(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
 226         }
 227 #endif
 228         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 229 }
 230
 231
 232 static void end_sb1250_irq(unsigned int irq)
 233 {
 234         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 235                 sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 236         }
 237 }
 238
 239
 240 void __init init_sb1250_irqs(void)
 241 {
 242         int i;
 243
 244         for (i = 0; i < NR_IRQS; i++) {
 245                 irq_desc[i].status = IRQ_DISABLED;
 246                 irq_desc[i].action = 0;
 247                 irq_desc[i].depth = 1;
 248                 if (i < SB1250_NR_IRQS) {
 249                         irq_desc[i].handler = &sb1250_irq_type;
 250                         sb1250_irq_owner[i] = 0;
 251                 } else {
 252                         irq_desc[i].handler = &no_irq_type;
 253                 }
 254         }
 255 }
 256
 257
 258 static irqreturn_t  sb1250_dummy_handler(int irq, void *dev_id,
 259         struct pt_regs *regs)
 260 {
 261         return IRQ_NONE;
 262 }
 263
 264 static struct irqaction sb1250_dummy_action = {
 265         .handler = sb1250_dummy_handler,
 266         .flags   = 0,
 267         .mask    = CPU_MASK_NONE,
 268         .name    = "sb1250-private",
 269         .next    = NULL,
 270         .dev_id  = 0
 271 };
 272
 273 int sb1250_steal_irq(int irq)
 274 {
 275         irq_desc_t *desc = irq_desc + irq;
 276         unsigned long flags;
 277         int retval = 0;
 278
 279         if (irq >= SB1250_NR_IRQS)
 280                 return -EINVAL;
 281
 282         spin_lock_irqsave(&desc->lock,flags);
 283         /* Don't allow sharing at all for these */
 284         if (desc->action != NULL)
 285                 retval = -EBUSY;
 286         else {
 287                 desc->action = &sb1250_dummy_action;
 288                 desc->depth = 0;
 289         }
 290         spin_unlock_irqrestore(&desc->lock,flags);
 291         return 0;
 292 }
 293
 294 /*
 295  *  arch_init_irq is called early in the boot sequence from init/main.c via
 296  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
 297  *  installing the handler that will be responsible for dispatching interrupts
 298  *  to the "right" place.
 299  */
 300 /*
 301  * For now, map all interrupts to IP[2].  We could save
 302  * some cycles by parceling out system interrupts to different
 303  * IP lines, but keep it simple for bringup.  We'll also direct
 304  * all interrupts to a single CPU; we should probably route
 305  * PCI and LDT to one cpu and everything else to the other
 306  * to balance the load a bit.
 307  *
 308  * On the second cpu, everything is set to IP5, which is
 309  * ignored, EXCEPT the mailbox interrupt.  That one is
 310  * set to IP[2] so it is handled.  This is needed so we
 311  * can do cross-cpu function calls, as requred by SMP
 312  */
 313
 314 #define IMR_IP2_VAL     K_INT_MAP_I0
 315 #define IMR_IP3_VAL     K_INT_MAP_I1
 316 #define IMR_IP4_VAL     K_INT_MAP_I2
 317 #define IMR_IP5_VAL     K_INT_MAP_I3
 318 #define IMR_IP6_VAL     K_INT_MAP_I4
 319
 320 void __init arch_init_irq(void)
 321 {
 322
 323         unsigned int i;
 324         u64 tmp;
 325         unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 326                 STATUSF_IP1 | STATUSF_IP0;
 327
 328         /* Default everything to IP2 */
 329         for (i = 0; i < SB1250_NR_IRQS; i++) {  /* was I0 */
 330                 __raw_writeq(IMR_IP2_VAL,
 331                              IOADDR(A_IMR_REGISTER(0,
 332                                                    R_IMR_INTERRUPT_MAP_BASE) +
 333                                     (i << 3)));
 334                 __raw_writeq(IMR_IP2_VAL,
 335                              IOADDR(A_IMR_REGISTER(1,
 336                                                    R_IMR_INTERRUPT_MAP_BASE) +
 337                                     (i << 3)));
 338         }
 339
 340         init_sb1250_irqs();
 341
 342         /*
 343          * Map the high 16 bits of the mailbox registers to IP[3], for
 344          * inter-cpu messages
 345          */
 346         /* Was I1 */
 347         __raw_writeq(IMR_IP3_VAL,
 348                      IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
 349                             (K_INT_MBOX_0 << 3)));
 350         __raw_writeq(IMR_IP3_VAL,
 351                      IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
 352                             (K_INT_MBOX_0 << 3)));
 353
 354         /* Clear the mailboxes.  The firmware may leave them dirty */
 355         __raw_writeq(0xffffffffffffffffULL,
 356                      IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
 357         __raw_writeq(0xffffffffffffffffULL,
 358                      IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));
 359
 360         /* Mask everything except the mailbox registers for both cpus */
 361         tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
 362         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
 363         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));
 364
 365         sb1250_steal_irq(K_INT_MBOX_0);
 366
 367         /*
 368          * Note that the timer interrupts are also mapped, but this is
 369          * done in sb1250_time_init().  Also, the profiling driver
 370          * does its own management of IP7.
 371          */
 372
 373 #ifdef CONFIG_KGDB
 374         imask |= STATUSF_IP6;
 375 #endif
 376         /* Enable necessary IPs, disable the rest */
 377         change_c0_status(ST0_IM, imask);
 378
 379 #ifdef CONFIG_KGDB
 380         if (kgdb_flag) {
 381                 kgdb_irq = K_INT_UART_0 + kgdb_port;
 382
 383 #ifdef CONFIG_SIBYTE_SB1250_DUART
 384                 sb1250_duart_present[kgdb_port] = 0;
 385 #endif
 386                 /* Setup uart 1 settings, mapper */
 387                 __raw_writeq(M_DUART_IMR_BRK,
 388                              IOADDR(A_DUART_IMRREG(kgdb_port)));
 389
 390                 sb1250_steal_irq(kgdb_irq);
 391                 __raw_writeq(IMR_IP6_VAL,
 392                              IOADDR(A_IMR_REGISTER(0,
 393                                                    R_IMR_INTERRUPT_MAP_BASE) +
 394                                     (kgdb_irq << 3)));
 395                 sb1250_unmask_irq(0, kgdb_irq);
 396         }
 397 #endif
 398 }
 399
 400 #ifdef CONFIG_KGDB
 401
 402 #include <linux/delay.h>
 403
 404 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 405 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 406
 407 static void sb1250_kgdb_interrupt(struct pt_regs *regs)
 408 {
 409         /*
 410          * Clear break-change status (allow some time for the remote
 411          * host to stop the break, since we would see another
 412          * interrupt on the end-of-break too)
 413          */
 414         kstat_this_cpu.irqs[kgdb_irq]++;
 415         mdelay(500);
 416         duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
 417                                 M_DUART_RX_EN | M_DUART_TX_EN);
 418         set_async_breakpoint(&regs->cp0_epc);
 419 }
 420
 421 #endif  /* CONFIG_KGDB */
 422
 423 static inline int dclz(unsigned long long x)
 424 {
 425         int lz;
 426
 427         __asm__ (
 428         "       .set    push                                            \n"
 429         "       .set    mips64                                          \n"
 430         "       dclz    %0, %1                                          \n"
 431         "       .set    pop                                             \n"
 432         : "=r" (lz)
 433         : "r" (x));
 434
 435         return lz;
 436 }
 437
 438 asmlinkage void plat_irq_dispatch(struct pt_regs *regs)
 439 {
 440         unsigned int pending;
 441
 442 #ifdef CONFIG_SIBYTE_SB1250_PROF
 443         /* Set compare to count to silence count/compare timer interrupts */
 444         write_c0_count(read_c0_count());
 445 #endif
 446
 447         /*
 448          * What a pain. We have to be really careful saving the upper 32 bits
 449          * of any * register across function calls if we don't want them
 450          * trashed--since were running in -o32, the calling routing never saves
 451          * the full 64 bits of a register across a function call.  Being the
 452          * interrupt handler, we're guaranteed that interrupts are disabled
 453          * during this code so we don't have to worry about random interrupts
 454          * blasting the high 32 bits.
 455          */
 456
 457         pending = read_c0_cause();
 458
 459 #ifdef CONFIG_SIBYTE_SB1250_PROF
 460         if (pending & CAUSEF_IP7) { /* Cpu performance counter interrupt */
 461                 sbprof_cpu_intr(exception_epc(regs));
 462         }
 463 #endif
 464
 465         if (pending & CAUSEF_IP4)
 466                 sb1250_timer_interrupt(regs);
 467
 468 #ifdef CONFIG_SMP
 469         if (pending & CAUSEF_IP3)
 470                 sb1250_mailbox_interrupt(regs);
 471 #endif
 472
 473 #ifdef CONFIG_KGDB
 474         if (pending & CAUSEF_IP6)                       /* KGDB (uart 1) */
 475                 sb1250_kgdb_interrupt(regs);
 476 #endif
 477
 478         if (pending & CAUSEF_IP2) {
 479                 unsigned long long mask;
 480
 481                 /*
 482                  * Default...we've hit an IP[2] interrupt, which means we've
 483                  * got to check the 1250 interrupt registers to figure out what
 484                  * to do.  Need to detect which CPU we're on, now that
 485                  ~ smp_affinity is supported.
 486                  */
 487                 mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
 488                                               R_IMR_INTERRUPT_STATUS_BASE)));
 489                 if (mask)
 490                         do_IRQ(63 - dclz(mask), regs);
 491         }
 492 }