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/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/linkage.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/smp.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/io.h>
  32
  33 #include <asm/sibyte/sb1250_regs.h>
  34 #include <asm/sibyte/sb1250_int.h>
  35 #include <asm/sibyte/sb1250_uart.h>
  36 #include <asm/sibyte/sb1250_scd.h>
  37 #include <asm/sibyte/sb1250.h>
  38
  39 /*
  40  * These are the routines that handle all the low level interrupt stuff.
  41  * Actions handled here are: initialization of the interrupt map, requesting of
  42  * interrupt lines by handlers, dispatching if interrupts to handlers, probing
  43  * for interrupt lines
  44  */
  45
  46
  47 static void end_sb1250_irq(unsigned int irq);
  48 static void enable_sb1250_irq(unsigned int irq);
  49 static void disable_sb1250_irq(unsigned int irq);
  50 static void ack_sb1250_irq(unsigned int irq);
  51 #ifdef CONFIG_SMP
  52 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
  53 #endif
  54
  55 #ifdef CONFIG_SIBYTE_HAS_LDT
  56 extern unsigned long ldt_eoi_space;
  57 #endif
  58
  59 #ifdef CONFIG_KGDB
  60 static int kgdb_irq;
  61
  62 /* Default to UART1 */
  63 int kgdb_port = 1;
  64 #ifdef CONFIG_SIBYTE_SB1250_DUART
  65 extern char sb1250_duart_present[];
  66 #endif
  67 #endif
  68
  69 static struct irq_chip sb1250_irq_type = {
  70         .name = "SB1250-IMR",
  71         .ack = ack_sb1250_irq,
  72         .mask = disable_sb1250_irq,
  73         .mask_ack = ack_sb1250_irq,
  74         .unmask = enable_sb1250_irq,
  75         .end = end_sb1250_irq,
  76 #ifdef CONFIG_SMP
  77         .set_affinity = sb1250_set_affinity
  78 #endif
  79 };
  80
  81 /* Store the CPU id (not the logical number) */
  82 int sb1250_irq_owner[SB1250_NR_IRQS];
  83
  84 DEFINE_SPINLOCK(sb1250_imr_lock);
  85
  86 void sb1250_mask_irq(int cpu, int irq)
  87 {
  88         unsigned long flags;
  89         u64 cur_ints;
  90
  91         spin_lock_irqsave(&sb1250_imr_lock, flags);
  92         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
  93                                         R_IMR_INTERRUPT_MASK));
  94         cur_ints |= (((u64) 1) << irq);
  95         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
  96                                         R_IMR_INTERRUPT_MASK));
  97         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
  98 }
  99
 100 void sb1250_unmask_irq(int cpu, int irq)
 101 {
 102         unsigned long flags;
 103         u64 cur_ints;
 104
 105         spin_lock_irqsave(&sb1250_imr_lock, flags);
 106         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 107                                         R_IMR_INTERRUPT_MASK));
 108         cur_ints &= ~(((u64) 1) << irq);
 109         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 110                                         R_IMR_INTERRUPT_MASK));
 111         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 112 }
 113
 114 #ifdef CONFIG_SMP
 115 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 116 {
 117         int i = 0, old_cpu, cpu, int_on;
 118         u64 cur_ints;
 119         struct irq_desc *desc = irq_desc + irq;
 120         unsigned long flags;
 121
 122         i = first_cpu(mask);
 123
 124         if (cpus_weight(mask) > 1) {
 125                 printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 126                 return;
 127         }
 128
 129         /* Convert logical CPU to physical CPU */
 130         cpu = cpu_logical_map(i);
 131
 132         /* Protect against other affinity changers and IMR manipulation */
 133         spin_lock_irqsave(&desc->lock, flags);
 134         spin_lock(&sb1250_imr_lock);
 135
 136         /* Swizzle each CPU's IMR (but leave the IP selection alone) */
 137         old_cpu = sb1250_irq_owner[irq];
 138         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
 139                                         R_IMR_INTERRUPT_MASK));
 140         int_on = !(cur_ints & (((u64) 1) << irq));
 141         if (int_on) {
 142                 /* If it was on, mask it */
 143                 cur_ints |= (((u64) 1) << irq);
 144                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
 145                                         R_IMR_INTERRUPT_MASK));
 146         }
 147         sb1250_irq_owner[irq] = cpu;
 148         if (int_on) {
 149                 /* unmask for the new CPU */
 150                 cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 151                                         R_IMR_INTERRUPT_MASK));
 152                 cur_ints &= ~(((u64) 1) << irq);
 153                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 154                                         R_IMR_INTERRUPT_MASK));
 155         }
 156         spin_unlock(&sb1250_imr_lock);
 157         spin_unlock_irqrestore(&desc->lock, flags);
 158 }
 159 #endif
 160
 161 /*****************************************************************************/
 162
 163 static void disable_sb1250_irq(unsigned int irq)
 164 {
 165         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 166 }
 167
 168 static void enable_sb1250_irq(unsigned int irq)
 169 {
 170         sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 171 }
 172
 173
 174 static void ack_sb1250_irq(unsigned int irq)
 175 {
 176 #ifdef CONFIG_SIBYTE_HAS_LDT
 177         u64 pending;
 178
 179         /*
 180          * If the interrupt was an HT interrupt, now is the time to
 181          * clear it.  NOTE: we assume the HT bridge was set up to
 182          * deliver the interrupts to all CPUs (which makes affinity
 183          * changing easier for us)
 184          */
 185         pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
 186                                                     R_IMR_LDT_INTERRUPT)));
 187         pending &= ((u64)1 << (irq));
 188         if (pending) {
 189                 int i;
 190                 for (i=0; i<NR_CPUS; i++) {
 191                         int cpu;
 192 #ifdef CONFIG_SMP
 193                         cpu = cpu_logical_map(i);
 194 #else
 195                         cpu = i;
 196 #endif
 197                         /*
 198                          * Clear for all CPUs so an affinity switch
 199                          * doesn't find an old status
 200                          */
 201                         __raw_writeq(pending,
 202                                      IOADDR(A_IMR_REGISTER(cpu,
 203                                                 R_IMR_LDT_INTERRUPT_CLR)));
 204                 }
 205
 206                 /*
 207                  * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 208                  * Pass 2, the LDT world may be edge-triggered, but
 209                  * this EOI shouldn't hurt.  If they are
 210                  * level-sensitive, the EOI is required.
 211                  */
 212                 *(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
 213         }
 214 #endif
 215         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 216 }
 217
 218
 219 static void end_sb1250_irq(unsigned int irq)
 220 {
 221         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 222                 sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 223         }
 224 }
 225
 226
 227 void __init init_sb1250_irqs(void)
 228 {
 229         int i;
 230
 231         for (i = 0; i < SB1250_NR_IRQS; i++) {
 232                 set_irq_chip(i, &sb1250_irq_type);
 233                 sb1250_irq_owner[i] = 0;
 234         }
 235 }
 236
 237
 238 static irqreturn_t  sb1250_dummy_handler(int irq, void *dev_id)
 239 {
 240         return IRQ_NONE;
 241 }
 242
 243 static struct irqaction sb1250_dummy_action = {
 244         .handler = sb1250_dummy_handler,
 245         .flags   = 0,
 246         .mask    = CPU_MASK_NONE,
 247         .name    = "sb1250-private",
 248         .next    = NULL,
 249         .dev_id  = 0
 250 };
 251
 252 int sb1250_steal_irq(int irq)
 253 {
 254         struct irq_desc *desc = irq_desc + irq;
 255         unsigned long flags;
 256         int retval = 0;
 257
 258         if (irq >= SB1250_NR_IRQS)
 259                 return -EINVAL;
 260
 261         spin_lock_irqsave(&desc->lock,flags);
 262         /* Don't allow sharing at all for these */
 263         if (desc->action != NULL)
 264                 retval = -EBUSY;
 265         else {
 266                 desc->action = &sb1250_dummy_action;
 267                 desc->depth = 0;
 268         }
 269         spin_unlock_irqrestore(&desc->lock,flags);
 270         return 0;
 271 }
 272
 273 /*
 274  *  arch_init_irq is called early in the boot sequence from init/main.c via
 275  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
 276  *  installing the handler that will be responsible for dispatching interrupts
 277  *  to the "right" place.
 278  */
 279 /*
 280  * For now, map all interrupts to IP[2].  We could save
 281  * some cycles by parceling out system interrupts to different
 282  * IP lines, but keep it simple for bringup.  We'll also direct
 283  * all interrupts to a single CPU; we should probably route
 284  * PCI and LDT to one cpu and everything else to the other
 285  * to balance the load a bit.
 286  *
 287  * On the second cpu, everything is set to IP5, which is
 288  * ignored, EXCEPT the mailbox interrupt.  That one is
 289  * set to IP[2] so it is handled.  This is needed so we
 290  * can do cross-cpu function calls, as requred by SMP
 291  */
 292
 293 #define IMR_IP2_VAL     K_INT_MAP_I0
 294 #define IMR_IP3_VAL     K_INT_MAP_I1
 295 #define IMR_IP4_VAL     K_INT_MAP_I2
 296 #define IMR_IP5_VAL     K_INT_MAP_I3
 297 #define IMR_IP6_VAL     K_INT_MAP_I4
 298
 299 void __init arch_init_irq(void)
 300 {
 301
 302         unsigned int i;
 303         u64 tmp;
 304         unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 305                 STATUSF_IP1 | STATUSF_IP0;
 306
 307         /* Default everything to IP2 */
 308         for (i = 0; i < SB1250_NR_IRQS; i++) {  /* was I0 */
 309                 __raw_writeq(IMR_IP2_VAL,
 310                              IOADDR(A_IMR_REGISTER(0,
 311                                                    R_IMR_INTERRUPT_MAP_BASE) +
 312                                     (i << 3)));
 313                 __raw_writeq(IMR_IP2_VAL,
 314                              IOADDR(A_IMR_REGISTER(1,
 315                                                    R_IMR_INTERRUPT_MAP_BASE) +
 316                                     (i << 3)));
 317         }
 318
 319         init_sb1250_irqs();
 320
 321         /*
 322          * Map the high 16 bits of the mailbox registers to IP[3], for
 323          * inter-cpu messages
 324          */
 325         /* Was I1 */
 326         __raw_writeq(IMR_IP3_VAL,
 327                      IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
 328                             (K_INT_MBOX_0 << 3)));
 329         __raw_writeq(IMR_IP3_VAL,
 330                      IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
 331                             (K_INT_MBOX_0 << 3)));
 332
 333         /* Clear the mailboxes.  The firmware may leave them dirty */
 334         __raw_writeq(0xffffffffffffffffULL,
 335                      IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
 336         __raw_writeq(0xffffffffffffffffULL,
 337                      IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));
 338
 339         /* Mask everything except the mailbox registers for both cpus */
 340         tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
 341         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
 342         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));
 343
 344         sb1250_steal_irq(K_INT_MBOX_0);
 345
 346         /*
 347          * Note that the timer interrupts are also mapped, but this is
 348          * done in sb1250_time_init().  Also, the profiling driver
 349          * does its own management of IP7.
 350          */
 351
 352 #ifdef CONFIG_KGDB
 353         imask |= STATUSF_IP6;
 354 #endif
 355         /* Enable necessary IPs, disable the rest */
 356         change_c0_status(ST0_IM, imask);
 357
 358 #ifdef CONFIG_KGDB
 359         if (kgdb_flag) {
 360                 kgdb_irq = K_INT_UART_0 + kgdb_port;
 361
 362 #ifdef CONFIG_SIBYTE_SB1250_DUART
 363                 sb1250_duart_present[kgdb_port] = 0;
 364 #endif
 365                 /* Setup uart 1 settings, mapper */
 366                 __raw_writeq(M_DUART_IMR_BRK,
 367                              IOADDR(A_DUART_IMRREG(kgdb_port)));
 368
 369                 sb1250_steal_irq(kgdb_irq);
 370                 __raw_writeq(IMR_IP6_VAL,
 371                              IOADDR(A_IMR_REGISTER(0,
 372                                                    R_IMR_INTERRUPT_MAP_BASE) +
 373                                     (kgdb_irq << 3)));
 374                 sb1250_unmask_irq(0, kgdb_irq);
 375         }
 376 #endif
 377 }
 378
 379 #ifdef CONFIG_KGDB
 380
 381 #include <linux/delay.h>
 382
 383 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 384 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port,reg)))
 385
 386 static void sb1250_kgdb_interrupt(void)
 387 {
 388         /*
 389          * Clear break-change status (allow some time for the remote
 390          * host to stop the break, since we would see another
 391          * interrupt on the end-of-break too)
 392          */
 393         kstat_this_cpu.irqs[kgdb_irq]++;
 394         mdelay(500);
 395         duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
 396                                 M_DUART_RX_EN | M_DUART_TX_EN);
 397         set_async_breakpoint(&get_irq_regs()->cp0_epc);
 398 }
 399
 400 #endif  /* CONFIG_KGDB */
 401
 402 extern void sb1250_timer_interrupt(void);
 403 extern void sb1250_mailbox_interrupt(void);
 404
 405 asmlinkage void plat_irq_dispatch(void)
 406 {
 407         unsigned int pending;
 408
 409 #ifdef CONFIG_SIBYTE_SB1250_PROF
 410         /* Set compare to count to silence count/compare timer interrupts */
 411         write_c0_compare(read_c0_count());
 412 #endif
 413
 414         /*
 415          * What a pain. We have to be really careful saving the upper 32 bits
 416          * of any * register across function calls if we don't want them
 417          * trashed--since were running in -o32, the calling routing never saves
 418          * the full 64 bits of a register across a function call.  Being the
 419          * interrupt handler, we're guaranteed that interrupts are disabled
 420          * during this code so we don't have to worry about random interrupts
 421          * blasting the high 32 bits.
 422          */
 423
 424         pending = read_c0_cause() & read_c0_status() & ST0_IM;
 425
 426 #ifdef CONFIG_SIBYTE_SB1250_PROF
 427         if (pending & CAUSEF_IP7) /* Cpu performance counter interrupt */
 428                 sbprof_cpu_intr();
 429         else
 430 #endif
 431
 432         if (pending & CAUSEF_IP4)
 433                 sb1250_timer_interrupt();
 434
 435 #ifdef CONFIG_SMP
 436         else if (pending & CAUSEF_IP3)
 437                 sb1250_mailbox_interrupt();
 438 #endif
 439
 440 #ifdef CONFIG_KGDB
 441         else if (pending & CAUSEF_IP6)                  /* KGDB (uart 1) */
 442                 sb1250_kgdb_interrupt();
 443 #endif
 444
 445         else if (pending & CAUSEF_IP2) {
 446                 unsigned long long mask;
 447
 448                 /*
 449                  * Default...we've hit an IP[2] interrupt, which means we've
 450                  * got to check the 1250 interrupt registers to figure out what
 451                  * to do.  Need to detect which CPU we're on, now that
 452                  * smp_affinity is supported.
 453                  */
 454                 mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
 455                                               R_IMR_INTERRUPT_STATUS_BASE)));
 456                 if (mask)
 457                         do_IRQ(fls64(mask) - 1);
 458                 else
 459                         spurious_interrupt();
 460         } else
 461                 spurious_interrupt();
 462 }