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/time.h>
  32 #include <asm/io.h>
  33
  34 #include <asm/sibyte/sb1250_regs.h>
  35 #include <asm/sibyte/sb1250_int.h>
  36 #include <asm/sibyte/sb1250_uart.h>
  37 #include <asm/sibyte/sb1250_scd.h>
  38 #include <asm/sibyte/sb1250.h>
  39
  40 /*
  41  * These are the routines that handle all the low level interrupt stuff.
  42  * Actions handled here are: initialization of the interrupt map, requesting of
  43  * interrupt lines by handlers, dispatching if interrupts to handlers, probing
  44  * for interrupt lines
  45  */
  46
  47
  48 static void end_sb1250_irq(unsigned int irq);
  49 static void enable_sb1250_irq(unsigned int irq);
  50 static void disable_sb1250_irq(unsigned int irq);
  51 static void ack_sb1250_irq(unsigned int irq);
  52 #ifdef CONFIG_SMP
  53 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask);
  54 #endif
  55
  56 #ifdef CONFIG_SIBYTE_HAS_LDT
  57 extern unsigned long ldt_eoi_space;
  58 #endif
  59
  60 #ifdef CONFIG_KGDB
  61 static int kgdb_irq;
  62
  63 /* Default to UART1 */
  64 int kgdb_port = 1;
  65 #ifdef CONFIG_SERIAL_SB1250_DUART
  66 extern char sb1250_duart_present[];
  67 #endif
  68 #endif
  69
  70 static struct irq_chip sb1250_irq_type = {
  71         .name = "SB1250-IMR",
  72         .ack = ack_sb1250_irq,
  73         .mask = disable_sb1250_irq,
  74         .mask_ack = ack_sb1250_irq,
  75         .unmask = enable_sb1250_irq,
  76         .end = end_sb1250_irq,
  77 #ifdef CONFIG_SMP
  78         .set_affinity = sb1250_set_affinity
  79 #endif
  80 };
  81
  82 /* Store the CPU id (not the logical number) */
  83 int sb1250_irq_owner[SB1250_NR_IRQS];
  84
  85 DEFINE_SPINLOCK(sb1250_imr_lock);
  86
  87 void sb1250_mask_irq(int cpu, int irq)
  88 {
  89         unsigned long flags;
  90         u64 cur_ints;
  91
  92         spin_lock_irqsave(&sb1250_imr_lock, flags);
  93         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
  94                                         R_IMR_INTERRUPT_MASK));
  95         cur_ints |= (((u64) 1) << irq);
  96         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
  97                                         R_IMR_INTERRUPT_MASK));
  98         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
  99 }
 100
 101 void sb1250_unmask_irq(int cpu, int irq)
 102 {
 103         unsigned long flags;
 104         u64 cur_ints;
 105
 106         spin_lock_irqsave(&sb1250_imr_lock, flags);
 107         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 108                                         R_IMR_INTERRUPT_MASK));
 109         cur_ints &= ~(((u64) 1) << irq);
 110         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 111                                         R_IMR_INTERRUPT_MASK));
 112         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
 113 }
 114
 115 #ifdef CONFIG_SMP
 116 static void sb1250_set_affinity(unsigned int irq, cpumask_t mask)
 117 {
 118         int i = 0, old_cpu, cpu, int_on;
 119         u64 cur_ints;
 120         struct irq_desc *desc = irq_desc + irq;
 121         unsigned long flags;
 122
 123         i = first_cpu(mask);
 124
 125         if (cpus_weight(mask) > 1) {
 126                 printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 127                 return;
 128         }
 129
 130         /* Convert logical CPU to physical CPU */
 131         cpu = cpu_logical_map(i);
 132
 133         /* Protect against other affinity changers and IMR manipulation */
 134         spin_lock_irqsave(&desc->lock, flags);
 135         spin_lock(&sb1250_imr_lock);
 136
 137         /* Swizzle each CPU's IMR (but leave the IP selection alone) */
 138         old_cpu = sb1250_irq_owner[irq];
 139         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
 140                                         R_IMR_INTERRUPT_MASK));
 141         int_on = !(cur_ints & (((u64) 1) << irq));
 142         if (int_on) {
 143                 /* If it was on, mask it */
 144                 cur_ints |= (((u64) 1) << irq);
 145                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
 146                                         R_IMR_INTERRUPT_MASK));
 147         }
 148         sb1250_irq_owner[irq] = cpu;
 149         if (int_on) {
 150                 /* unmask for the new CPU */
 151                 cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 152                                         R_IMR_INTERRUPT_MASK));
 153                 cur_ints &= ~(((u64) 1) << irq);
 154                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 155                                         R_IMR_INTERRUPT_MASK));
 156         }
 157         spin_unlock(&sb1250_imr_lock);
 158         spin_unlock_irqrestore(&desc->lock, flags);
 159 }
 160 #endif
 161
 162 /*****************************************************************************/
 163
 164 static void disable_sb1250_irq(unsigned int irq)
 165 {
 166         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 167 }
 168
 169 static void enable_sb1250_irq(unsigned int irq)
 170 {
 171         sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 172 }
 173
 174
 175 static void ack_sb1250_irq(unsigned int irq)
 176 {
 177 #ifdef CONFIG_SIBYTE_HAS_LDT
 178         u64 pending;
 179
 180         /*
 181          * If the interrupt was an HT interrupt, now is the time to
 182          * clear it.  NOTE: we assume the HT bridge was set up to
 183          * deliver the interrupts to all CPUs (which makes affinity
 184          * changing easier for us)
 185          */
 186         pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
 187                                                     R_IMR_LDT_INTERRUPT)));
 188         pending &= ((u64)1 << (irq));
 189         if (pending) {
 190                 int i;
 191                 for (i=0; i<NR_CPUS; i++) {
 192                         int cpu;
 193 #ifdef CONFIG_SMP
 194                         cpu = cpu_logical_map(i);
 195 #else
 196                         cpu = i;
 197 #endif
 198                         /*
 199                          * Clear for all CPUs so an affinity switch
 200                          * doesn't find an old status
 201                          */
 202                         __raw_writeq(pending,
 203                                      IOADDR(A_IMR_REGISTER(cpu,
 204                                                 R_IMR_LDT_INTERRUPT_CLR)));
 205                 }
 206
 207                 /*
 208                  * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 209                  * Pass 2, the LDT world may be edge-triggered, but
 210                  * this EOI shouldn't hurt.  If they are
 211                  * level-sensitive, the EOI is required.
 212                  */
 213                 *(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
 214         }
 215 #endif
 216         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 217 }
 218
 219
 220 static void end_sb1250_irq(unsigned int irq)
 221 {
 222         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 223                 sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 224         }
 225 }
 226
 227
 228 void __init init_sb1250_irqs(void)
 229 {
 230         int i;
 231
 232         for (i = 0; i < SB1250_NR_IRQS; i++) {
 233                 set_irq_chip(i, &sb1250_irq_type);
 234                 sb1250_irq_owner[i] = 0;
 235         }
 236 }
 237
 238
 239 static irqreturn_t  sb1250_dummy_handler(int irq, void *dev_id)
 240 {
 241         return IRQ_NONE;
 242 }
 243
 244 static struct irqaction sb1250_dummy_action = {
 245         .handler = sb1250_dummy_handler,
 246         .flags   = 0,
 247         .mask    = CPU_MASK_NONE,
 248         .name    = "sb1250-private",
 249         .next    = NULL,
 250         .dev_id  = 0
 251 };
 252
 253 int sb1250_steal_irq(int irq)
 254 {
 255         struct irq_desc *desc = irq_desc + irq;
 256         unsigned long flags;
 257         int retval = 0;
 258
 259         if (irq >= SB1250_NR_IRQS)
 260                 return -EINVAL;
 261
 262         spin_lock_irqsave(&desc->lock, flags);
 263         /* Don't allow sharing at all for these */
 264         if (desc->action != NULL)
 265                 retval = -EBUSY;
 266         else {
 267                 desc->action = &sb1250_dummy_action;
 268                 desc->depth = 0;
 269         }
 270         spin_unlock_irqrestore(&desc->lock, flags);
 271         return 0;
 272 }
 273
 274 /*
 275  *  arch_init_irq is called early in the boot sequence from init/main.c via
 276  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
 277  *  installing the handler that will be responsible for dispatching interrupts
 278  *  to the "right" place.
 279  */
 280 /*
 281  * For now, map all interrupts to IP[2].  We could save
 282  * some cycles by parceling out system interrupts to different
 283  * IP lines, but keep it simple for bringup.  We'll also direct
 284  * all interrupts to a single CPU; we should probably route
 285  * PCI and LDT to one cpu and everything else to the other
 286  * to balance the load a bit.
 287  *
 288  * On the second cpu, everything is set to IP5, which is
 289  * ignored, EXCEPT the mailbox interrupt.  That one is
 290  * set to IP[2] so it is handled.  This is needed so we
 291  * can do cross-cpu function calls, as requred by SMP
 292  */
 293
 294 #define IMR_IP2_VAL     K_INT_MAP_I0
 295 #define IMR_IP3_VAL     K_INT_MAP_I1
 296 #define IMR_IP4_VAL     K_INT_MAP_I2
 297 #define IMR_IP5_VAL     K_INT_MAP_I3
 298 #define IMR_IP6_VAL     K_INT_MAP_I4
 299
 300 void __init arch_init_irq(void)
 301 {
 302
 303         unsigned int i;
 304         u64 tmp;
 305         unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 306                 STATUSF_IP1 | STATUSF_IP0;
 307
 308         /* Default everything to IP2 */
 309         for (i = 0; i < SB1250_NR_IRQS; i++) {  /* was I0 */
 310                 __raw_writeq(IMR_IP2_VAL,
 311                              IOADDR(A_IMR_REGISTER(0,
 312                                                    R_IMR_INTERRUPT_MAP_BASE) +
 313                                     (i << 3)));
 314                 __raw_writeq(IMR_IP2_VAL,
 315                              IOADDR(A_IMR_REGISTER(1,
 316                                                    R_IMR_INTERRUPT_MAP_BASE) +
 317                                     (i << 3)));
 318         }
 319
 320         init_sb1250_irqs();
 321
 322         /*
 323          * Map the high 16 bits of the mailbox registers to IP[3], for
 324          * inter-cpu messages
 325          */
 326         /* Was I1 */
 327         __raw_writeq(IMR_IP3_VAL,
 328                      IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
 329                             (K_INT_MBOX_0 << 3)));
 330         __raw_writeq(IMR_IP3_VAL,
 331                      IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
 332                             (K_INT_MBOX_0 << 3)));
 333
 334         /* Clear the mailboxes.  The firmware may leave them dirty */
 335         __raw_writeq(0xffffffffffffffffULL,
 336                      IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
 337         __raw_writeq(0xffffffffffffffffULL,
 338                      IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));
 339
 340         /* Mask everything except the mailbox registers for both cpus */
 341         tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
 342         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
 343         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));
 344
 345         sb1250_steal_irq(K_INT_MBOX_0);
 346
 347         /*
 348          * Note that the timer interrupts are also mapped, but this is
 349          * done in sb1250_time_init().  Also, the profiling driver
 350          * does its own management of IP7.
 351          */
 352
 353 #ifdef CONFIG_KGDB
 354         imask |= STATUSF_IP6;
 355 #endif
 356         /* Enable necessary IPs, disable the rest */
 357         change_c0_status(ST0_IM, imask);
 358
 359 #ifdef CONFIG_KGDB
 360         if (kgdb_flag) {
 361                 kgdb_irq = K_INT_UART_0 + kgdb_port;
 362
 363 #ifdef CONFIG_SERIAL_SB1250_DUART
 364                 sb1250_duart_present[kgdb_port] = 0;
 365 #endif
 366                 /* Setup uart 1 settings, mapper */
 367                 __raw_writeq(M_DUART_IMR_BRK,
 368                              IOADDR(A_DUART_IMRREG(kgdb_port)));
 369
 370                 sb1250_steal_irq(kgdb_irq);
 371                 __raw_writeq(IMR_IP6_VAL,
 372                              IOADDR(A_IMR_REGISTER(0,
 373                                                    R_IMR_INTERRUPT_MAP_BASE) +
 374                                     (kgdb_irq << 3)));
 375                 sb1250_unmask_irq(0, kgdb_irq);
 376         }
 377 #endif
 378 }
 379
 380 #ifdef CONFIG_KGDB
 381
 382 #include <linux/delay.h>
 383
 384 #define duart_out(reg, val)     csr_out32(val, IOADDR(A_DUART_CHANREG(kgdb_port, reg)))
 385 #define duart_in(reg)           csr_in32(IOADDR(A_DUART_CHANREG(kgdb_port, reg)))
 386
 387 static void sb1250_kgdb_interrupt(void)
 388 {
 389         /*
 390          * Clear break-change status (allow some time for the remote
 391          * host to stop the break, since we would see another
 392          * interrupt on the end-of-break too)
 393          */
 394         kstat_this_cpu.irqs[kgdb_irq]++;
 395         mdelay(500);
 396         duart_out(R_DUART_CMD, V_DUART_MISC_CMD_RESET_BREAK_INT |
 397                                 M_DUART_RX_EN | M_DUART_TX_EN);
 398         set_async_breakpoint(&get_irq_regs()->cp0_epc);
 399 }
 400
 401 #endif  /* CONFIG_KGDB */
 402
 403 static inline void sb1250_timer_interrupt(void)
 404 {
 405         int cpu = smp_processor_id();
 406         int irq = K_INT_TIMER_0 + cpu;
 407
 408         irq_enter();
 409         kstat_this_cpu.irqs[irq]++;
 410
 411         write_seqlock(&xtime_lock);
 412
 413         /* ACK interrupt */
 414         ____raw_writeq(M_SCD_TIMER_ENABLE | M_SCD_TIMER_MODE_CONTINUOUS,
 415                        IOADDR(A_SCD_TIMER_REGISTER(cpu, R_SCD_TIMER_CFG)));
 416
 417         /*
 418          * call the generic timer interrupt handling
 419          */
 420         do_timer(1);
 421
 422         write_sequnlock(&xtime_lock);
 423
 424         /*
 425          * In UP mode, we call local_timer_interrupt() to do profiling
 426          * and process accouting.
 427          *
 428          * In SMP mode, local_timer_interrupt() is invoked by appropriate
 429          * low-level local timer interrupt handler.
 430          */
 431         local_timer_interrupt(irq);
 432
 433         irq_exit();
 434 }
 435
 436 extern void sb1250_mailbox_interrupt(void);
 437
 438 asmlinkage void plat_irq_dispatch(void)
 439 {
 440         unsigned int pending;
 441
 442         /*
 443          * What a pain. We have to be really careful saving the upper 32 bits
 444          * of any * register across function calls if we don't want them
 445          * trashed--since were running in -o32, the calling routing never saves
 446          * the full 64 bits of a register across a function call.  Being the
 447          * interrupt handler, we're guaranteed that interrupts are disabled
 448          * during this code so we don't have to worry about random interrupts
 449          * blasting the high 32 bits.
 450          */
 451
 452         pending = read_c0_cause() & read_c0_status() & ST0_IM;
 453
 454         if (pending & CAUSEF_IP7) /* CPU performance counter interrupt */
 455                 do_IRQ(MIPS_CPU_IRQ_BASE + 7);
 456         else if (pending & CAUSEF_IP4)
 457                 sb1250_timer_interrupt();
 458
 459 #ifdef CONFIG_SMP
 460         else if (pending & CAUSEF_IP3)
 461                 sb1250_mailbox_interrupt();
 462 #endif
 463
 464 #ifdef CONFIG_KGDB
 465         else if (pending & CAUSEF_IP6)                  /* KGDB (uart 1) */
 466                 sb1250_kgdb_interrupt();
 467 #endif
 468
 469         else if (pending & CAUSEF_IP2) {
 470                 unsigned long long mask;
 471
 472                 /*
 473                  * Default...we've hit an IP[2] interrupt, which means we've
 474                  * got to check the 1250 interrupt registers to figure out what
 475                  * to do.  Need to detect which CPU we're on, now that
 476                  * smp_affinity is supported.
 477                  */
 478                 mask = __raw_readq(IOADDR(A_IMR_REGISTER(smp_processor_id(),
 479                                               R_IMR_INTERRUPT_STATUS_BASE)));
 480                 if (mask)
 481                         do_IRQ(fls64(mask) - 1);
 482                 else
 483                         spurious_interrupt();
 484         } else
 485                 spurious_interrupt();
 486 }