arch/mips/sgi-ip27/ip27-irq.c

   1 /*
   2  * ip27-irq.c: Highlevel interrupt handling for IP27 architecture.
   3  *
   4  * Copyright (C) 1999, 2000 Ralf Baechle (ralf@gnu.org)
   5  * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
   6  * Copyright (C) 1999 - 2001 Kanoj Sarcar
   7  */
   8
   9 #undef DEBUG
  10
  11 #include <linux/init.h>
  12 #include <linux/irq.h>
  13 #include <linux/errno.h>
  14 #include <linux/signal.h>
  15 #include <linux/sched.h>
  16 #include <linux/types.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/ioport.h>
  19 #include <linux/timex.h>
  20 #include <linux/smp.h>
  21 #include <linux/random.h>
  22 #include <linux/kernel.h>
  23 #include <linux/kernel_stat.h>
  24 #include <linux/delay.h>
  25 #include <linux/bitops.h>
  26
  27 #include <asm/bootinfo.h>
  28 #include <asm/io.h>
  29 #include <asm/mipsregs.h>
  30 #include <asm/system.h>
  31
  32 #include <asm/processor.h>
  33 #include <asm/pci/bridge.h>
  34 #include <asm/sn/addrs.h>
  35 #include <asm/sn/agent.h>
  36 #include <asm/sn/arch.h>
  37 #include <asm/sn/hub.h>
  38 #include <asm/sn/intr.h>
  39
  40 /*
  41  * Linux has a controller-independent x86 interrupt architecture.
  42  * every controller has a 'controller-template', that is used
  43  * by the main code to do the right thing. Each driver-visible
  44  * interrupt source is transparently wired to the appropriate
  45  * controller. Thus drivers need not be aware of the
  46  * interrupt-controller.
  47  *
  48  * Various interrupt controllers we handle: 8259 PIC, SMP IO-APIC,
  49  * PIIX4's internal 8259 PIC and SGI's Visual Workstation Cobalt (IO-)APIC.
  50  * (IO-APICs assumed to be messaging to Pentium local-APICs)
  51  *
  52  * the code is designed to be easily extended with new/different
  53  * interrupt controllers, without having to do assembly magic.
  54  */
  55
  56 extern asmlinkage void ip27_irq(void);
  57
  58 extern struct bridge_controller *irq_to_bridge[];
  59 extern int irq_to_slot[];
  60
  61 /*
  62  * use these macros to get the encoded nasid and widget id
  63  * from the irq value
  64  */
  65 #define IRQ_TO_BRIDGE(i)                irq_to_bridge[(i)]
  66 #define SLOT_FROM_PCI_IRQ(i)            irq_to_slot[i]
  67
  68 static inline int alloc_level(int cpu, int irq)
  69 {
  70         struct hub_data *hub = hub_data(cpu_to_node(cpu));
  71         struct slice_data *si = cpu_data[cpu].data;
  72         int level;
  73
  74         level = find_first_zero_bit(hub->irq_alloc_mask, LEVELS_PER_SLICE);
  75         if (level >= LEVELS_PER_SLICE)
  76                 panic("Cpu %d flooded with devices\n", cpu);
  77
  78         __set_bit(level, hub->irq_alloc_mask);
  79         si->level_to_irq[level] = irq;
  80
  81         return level;
  82 }
  83
  84 static inline int find_level(cpuid_t *cpunum, int irq)
  85 {
  86         int cpu, i;
  87
  88         for_each_online_cpu(cpu) {
  89                 struct slice_data *si = cpu_data[cpu].data;
  90
  91                 for (i = BASE_PCI_IRQ; i < LEVELS_PER_SLICE; i++)
  92                         if (si->level_to_irq[i] == irq) {
  93                                 *cpunum = cpu;
  94
  95                                 return i;
  96                         }
  97         }
  98
  99         panic("Could not identify cpu/level for irq %d\n", irq);
 100 }
 101
 102 /*
 103  * Find first bit set
 104  */
 105 static int ms1bit(unsigned long x)
 106 {
 107         int b = 0, s;
 108
 109         s = 16; if (x >> 16 == 0) s = 0; b += s; x >>= s;
 110         s =  8; if (x >>  8 == 0) s = 0; b += s; x >>= s;
 111         s =  4; if (x >>  4 == 0) s = 0; b += s; x >>= s;
 112         s =  2; if (x >>  2 == 0) s = 0; b += s; x >>= s;
 113         s =  1; if (x >>  1 == 0) s = 0; b += s;
 114
 115         return b;
 116 }
 117
 118 /*
 119  * This code is unnecessarily complex, because we do IRQF_DISABLED
 120  * intr enabling. Basically, once we grab the set of intrs we need
 121  * to service, we must mask _all_ these interrupts; firstly, to make
 122  * sure the same intr does not intr again, causing recursion that
 123  * can lead to stack overflow. Secondly, we can not just mask the
 124  * one intr we are do_IRQing, because the non-masked intrs in the
 125  * first set might intr again, causing multiple servicings of the
 126  * same intr. This effect is mostly seen for intercpu intrs.
 127  * Kanoj 05.13.00
 128  */
 129
 130 static void ip27_do_irq_mask0(void)
 131 {
 132         int irq, swlevel;
 133         hubreg_t pend0, mask0;
 134         cpuid_t cpu = smp_processor_id();
 135         int pi_int_mask0 =
 136                 (cputoslice(cpu) == 0) ?  PI_INT_MASK0_A : PI_INT_MASK0_B;
 137
 138         /* copied from Irix intpend0() */
 139         pend0 = LOCAL_HUB_L(PI_INT_PEND0);
 140         mask0 = LOCAL_HUB_L(pi_int_mask0);
 141
 142         pend0 &= mask0;         /* Pick intrs we should look at */
 143         if (!pend0)
 144                 return;
 145
 146         swlevel = ms1bit(pend0);
 147 #ifdef CONFIG_SMP
 148         if (pend0 & (1UL << CPU_RESCHED_A_IRQ)) {
 149                 LOCAL_HUB_CLR_INTR(CPU_RESCHED_A_IRQ);
 150                 scheduler_ipi();
 151         } else if (pend0 & (1UL << CPU_RESCHED_B_IRQ)) {
 152                 LOCAL_HUB_CLR_INTR(CPU_RESCHED_B_IRQ);
 153                 scheduler_ipi();
 154         } else if (pend0 & (1UL << CPU_CALL_A_IRQ)) {
 155                 LOCAL_HUB_CLR_INTR(CPU_CALL_A_IRQ);
 156                 smp_call_function_interrupt();
 157         } else if (pend0 & (1UL << CPU_CALL_B_IRQ)) {
 158                 LOCAL_HUB_CLR_INTR(CPU_CALL_B_IRQ);
 159                 smp_call_function_interrupt();
 160         } else
 161 #endif
 162         {
 163                 /* "map" swlevel to irq */
 164                 struct slice_data *si = cpu_data[cpu].data;
 165
 166                 irq = si->level_to_irq[swlevel];
 167                 do_IRQ(irq);
 168         }
 169
 170         LOCAL_HUB_L(PI_INT_PEND0);
 171 }
 172
 173 static void ip27_do_irq_mask1(void)
 174 {
 175         int irq, swlevel;
 176         hubreg_t pend1, mask1;
 177         cpuid_t cpu = smp_processor_id();
 178         int pi_int_mask1 = (cputoslice(cpu) == 0) ?  PI_INT_MASK1_A : PI_INT_MASK1_B;
 179         struct slice_data *si = cpu_data[cpu].data;
 180
 181         /* copied from Irix intpend0() */
 182         pend1 = LOCAL_HUB_L(PI_INT_PEND1);
 183         mask1 = LOCAL_HUB_L(pi_int_mask1);
 184
 185         pend1 &= mask1;         /* Pick intrs we should look at */
 186         if (!pend1)
 187                 return;
 188
 189         swlevel = ms1bit(pend1);
 190         /* "map" swlevel to irq */
 191         irq = si->level_to_irq[swlevel];
 192         LOCAL_HUB_CLR_INTR(swlevel);
 193         do_IRQ(irq);
 194
 195         LOCAL_HUB_L(PI_INT_PEND1);
 196 }
 197
 198 static void ip27_prof_timer(void)
 199 {
 200         panic("CPU %d got a profiling interrupt", smp_processor_id());
 201 }
 202
 203 static void ip27_hub_error(void)
 204 {
 205         panic("CPU %d got a hub error interrupt", smp_processor_id());
 206 }
 207
 208 static int intr_connect_level(int cpu, int bit)
 209 {
 210         nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
 211         struct slice_data *si = cpu_data[cpu].data;
 212
 213         set_bit(bit, si->irq_enable_mask);
 214
 215         if (!cputoslice(cpu)) {
 216                 REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
 217                 REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
 218         } else {
 219                 REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
 220                 REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
 221         }
 222
 223         return 0;
 224 }
 225
 226 static int intr_disconnect_level(int cpu, int bit)
 227 {
 228         nasid_t nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
 229         struct slice_data *si = cpu_data[cpu].data;
 230
 231         clear_bit(bit, si->irq_enable_mask);
 232
 233         if (!cputoslice(cpu)) {
 234                 REMOTE_HUB_S(nasid, PI_INT_MASK0_A, si->irq_enable_mask[0]);
 235                 REMOTE_HUB_S(nasid, PI_INT_MASK1_A, si->irq_enable_mask[1]);
 236         } else {
 237                 REMOTE_HUB_S(nasid, PI_INT_MASK0_B, si->irq_enable_mask[0]);
 238                 REMOTE_HUB_S(nasid, PI_INT_MASK1_B, si->irq_enable_mask[1]);
 239         }
 240
 241         return 0;
 242 }
 243
 244 /* Startup one of the (PCI ...) IRQs routes over a bridge.  */
 245 static unsigned int startup_bridge_irq(struct irq_data *d)
 246 {
 247         struct bridge_controller *bc;
 248         bridgereg_t device;
 249         bridge_t *bridge;
 250         int pin, swlevel;
 251         cpuid_t cpu;
 252
 253         pin = SLOT_FROM_PCI_IRQ(d->irq);
 254         bc = IRQ_TO_BRIDGE(d->irq);
 255         bridge = bc->base;
 256
 257         pr_debug("bridge_startup(): irq= 0x%x  pin=%d\n", d->irq, pin);
 258         /*
 259          * "map" irq to a swlevel greater than 6 since the first 6 bits
 260          * of INT_PEND0 are taken
 261          */
 262         swlevel = find_level(&cpu, d->irq);
 263         bridge->b_int_addr[pin].addr = (0x20000 | swlevel | (bc->nasid << 8));
 264         bridge->b_int_enable |= (1 << pin);
 265         bridge->b_int_enable |= 0x7ffffe00;     /* more stuff in int_enable */
 266
 267         /*
 268          * Enable sending of an interrupt clear packt to the hub on a high to
 269          * low transition of the interrupt pin.
 270          *
 271          * IRIX sets additional bits in the address which are documented as
 272          * reserved in the bridge docs.
 273          */
 274         bridge->b_int_mode |= (1UL << pin);
 275
 276         /*
 277          * We assume the bridge to have a 1:1 mapping between devices
 278          * (slots) and intr pins.
 279          */
 280         device = bridge->b_int_device;
 281         device &= ~(7 << (pin*3));
 282         device |= (pin << (pin*3));
 283         bridge->b_int_device = device;
 284
 285         bridge->b_wid_tflush;
 286
 287         intr_connect_level(cpu, swlevel);
 288
 289         return 0;       /* Never anything pending.  */
 290 }
 291
 292 /* Shutdown one of the (PCI ...) IRQs routes over a bridge.  */
 293 static void shutdown_bridge_irq(struct irq_data *d)
 294 {
 295         struct bridge_controller *bc = IRQ_TO_BRIDGE(d->irq);
 296         bridge_t *bridge = bc->base;
 297         int pin, swlevel;
 298         cpuid_t cpu;
 299
 300         pr_debug("bridge_shutdown: irq 0x%x\n", d->irq);
 301         pin = SLOT_FROM_PCI_IRQ(d->irq);
 302
 303         /*
 304          * map irq to a swlevel greater than 6 since the first 6 bits
 305          * of INT_PEND0 are taken
 306          */
 307         swlevel = find_level(&cpu, d->irq);
 308         intr_disconnect_level(cpu, swlevel);
 309
 310         bridge->b_int_enable &= ~(1 << pin);
 311         bridge->b_wid_tflush;
 312 }
 313
 314 static inline void enable_bridge_irq(struct irq_data *d)
 315 {
 316         cpuid_t cpu;
 317         int swlevel;
 318
 319         swlevel = find_level(&cpu, d->irq);     /* Criminal offence */
 320         intr_connect_level(cpu, swlevel);
 321 }
 322
 323 static inline void disable_bridge_irq(struct irq_data *d)
 324 {
 325         cpuid_t cpu;
 326         int swlevel;
 327
 328         swlevel = find_level(&cpu, d->irq);     /* Criminal offence */
 329         intr_disconnect_level(cpu, swlevel);
 330 }
 331
 332 static struct irq_chip bridge_irq_type = {
 333         .name           = "bridge",
 334         .irq_startup    = startup_bridge_irq,
 335         .irq_shutdown   = shutdown_bridge_irq,
 336         .irq_mask       = disable_bridge_irq,
 337         .irq_unmask     = enable_bridge_irq,
 338 };
 339
 340 void register_bridge_irq(unsigned int irq)
 341 {
 342         irq_set_chip_and_handler(irq, &bridge_irq_type, handle_level_irq);
 343 }
 344
 345 int request_bridge_irq(struct bridge_controller *bc)
 346 {
 347         int irq = allocate_irqno();
 348         int swlevel, cpu;
 349         nasid_t nasid;
 350
 351         if (irq < 0)
 352                 return irq;
 353
 354         /*
 355          * "map" irq to a swlevel greater than 6 since the first 6 bits
 356          * of INT_PEND0 are taken
 357          */
 358         cpu = bc->irq_cpu;
 359         swlevel = alloc_level(cpu, irq);
 360         if (unlikely(swlevel < 0)) {
 361                 free_irqno(irq);
 362
 363                 return -EAGAIN;
 364         }
 365
 366         /* Make sure it's not already pending when we connect it. */
 367         nasid = COMPACT_TO_NASID_NODEID(cpu_to_node(cpu));
 368         REMOTE_HUB_CLR_INTR(nasid, swlevel);
 369
 370         intr_connect_level(cpu, swlevel);
 371
 372         register_bridge_irq(irq);
 373
 374         return irq;
 375 }
 376
 377 asmlinkage void plat_irq_dispatch(void)
 378 {
 379         unsigned long pending = read_c0_cause() & read_c0_status();
 380         extern unsigned int rt_timer_irq;
 381
 382         if (pending & CAUSEF_IP4)
 383                 do_IRQ(rt_timer_irq);
 384         else if (pending & CAUSEF_IP2)  /* PI_INT_PEND_0 or CC_PEND_{A|B} */
 385                 ip27_do_irq_mask0();
 386         else if (pending & CAUSEF_IP3)  /* PI_INT_PEND_1 */
 387                 ip27_do_irq_mask1();
 388         else if (pending & CAUSEF_IP5)
 389                 ip27_prof_timer();
 390         else if (pending & CAUSEF_IP6)
 391                 ip27_hub_error();
 392 }
 393
 394 void __init arch_init_irq(void)
 395 {
 396 }
 397
 398 void install_ipi(void)
 399 {
 400         int slice = LOCAL_HUB_L(PI_CPU_NUM);
 401         int cpu = smp_processor_id();
 402         struct slice_data *si = cpu_data[cpu].data;
 403         struct hub_data *hub = hub_data(cpu_to_node(cpu));
 404         int resched, call;
 405
 406         resched = CPU_RESCHED_A_IRQ + slice;
 407         __set_bit(resched, hub->irq_alloc_mask);
 408         __set_bit(resched, si->irq_enable_mask);
 409         LOCAL_HUB_CLR_INTR(resched);
 410
 411         call = CPU_CALL_A_IRQ + slice;
 412         __set_bit(call, hub->irq_alloc_mask);
 413         __set_bit(call, si->irq_enable_mask);
 414         LOCAL_HUB_CLR_INTR(call);
 415
 416         if (slice == 0) {
 417                 LOCAL_HUB_S(PI_INT_MASK0_A, si->irq_enable_mask[0]);
 418                 LOCAL_HUB_S(PI_INT_MASK1_A, si->irq_enable_mask[1]);
 419         } else {
 420                 LOCAL_HUB_S(PI_INT_MASK0_B, si->irq_enable_mask[0]);
 421                 LOCAL_HUB_S(PI_INT_MASK1_B, si->irq_enable_mask[1]);
 422         }
 423 }