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, const struct cpumask *mask);
  54 #endif
  55
  56 #ifdef CONFIG_SIBYTE_HAS_LDT
  57 extern unsigned long ldt_eoi_space;
  58 #endif
  59
  60 static struct irq_chip sb1250_irq_type = {
  61         .name = "SB1250-IMR",
  62         .ack = ack_sb1250_irq,
  63         .mask = disable_sb1250_irq,
  64         .mask_ack = ack_sb1250_irq,
  65         .unmask = enable_sb1250_irq,
  66         .end = end_sb1250_irq,
  67 #ifdef CONFIG_SMP
  68         .set_affinity = sb1250_set_affinity
  69 #endif
  70 };
  71
  72 /* Store the CPU id (not the logical number) */
  73 int sb1250_irq_owner[SB1250_NR_IRQS];
  74
  75 DEFINE_SPINLOCK(sb1250_imr_lock);
  76
  77 void sb1250_mask_irq(int cpu, int irq)
  78 {
  79         unsigned long flags;
  80         u64 cur_ints;
  81
  82         spin_lock_irqsave(&sb1250_imr_lock, flags);
  83         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
  84                                         R_IMR_INTERRUPT_MASK));
  85         cur_ints |= (((u64) 1) << irq);
  86         ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
  87                                         R_IMR_INTERRUPT_MASK));
  88         spin_unlock_irqrestore(&sb1250_imr_lock, flags);
  89 }
  90
  91 void sb1250_unmask_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 #ifdef CONFIG_SMP
 106 static void sb1250_set_affinity(unsigned int irq, const struct cpumask *mask)
 107 {
 108         int i = 0, old_cpu, cpu, int_on;
 109         u64 cur_ints;
 110         struct irq_desc *desc = irq_desc + irq;
 111         unsigned long flags;
 112
 113         i = cpumask_first(mask);
 114
 115         if (cpumask_weight(mask) > 1) {
 116                 printk("attempted to set irq affinity for irq %d to multiple CPUs\n", irq);
 117                 return;
 118         }
 119
 120         /* Convert logical CPU to physical CPU */
 121         cpu = cpu_logical_map(i);
 122
 123         /* Protect against other affinity changers and IMR manipulation */
 124         spin_lock_irqsave(&desc->lock, flags);
 125         spin_lock(&sb1250_imr_lock);
 126
 127         /* Swizzle each CPU's IMR (but leave the IP selection alone) */
 128         old_cpu = sb1250_irq_owner[irq];
 129         cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(old_cpu) +
 130                                         R_IMR_INTERRUPT_MASK));
 131         int_on = !(cur_ints & (((u64) 1) << irq));
 132         if (int_on) {
 133                 /* If it was on, mask it */
 134                 cur_ints |= (((u64) 1) << irq);
 135                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(old_cpu) +
 136                                         R_IMR_INTERRUPT_MASK));
 137         }
 138         sb1250_irq_owner[irq] = cpu;
 139         if (int_on) {
 140                 /* unmask for the new CPU */
 141                 cur_ints = ____raw_readq(IOADDR(A_IMR_MAPPER(cpu) +
 142                                         R_IMR_INTERRUPT_MASK));
 143                 cur_ints &= ~(((u64) 1) << irq);
 144                 ____raw_writeq(cur_ints, IOADDR(A_IMR_MAPPER(cpu) +
 145                                         R_IMR_INTERRUPT_MASK));
 146         }
 147         spin_unlock(&sb1250_imr_lock);
 148         spin_unlock_irqrestore(&desc->lock, flags);
 149 }
 150 #endif
 151
 152 /*****************************************************************************/
 153
 154 static void disable_sb1250_irq(unsigned int irq)
 155 {
 156         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 157 }
 158
 159 static void enable_sb1250_irq(unsigned int irq)
 160 {
 161         sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 162 }
 163
 164
 165 static void ack_sb1250_irq(unsigned int irq)
 166 {
 167 #ifdef CONFIG_SIBYTE_HAS_LDT
 168         u64 pending;
 169
 170         /*
 171          * If the interrupt was an HT interrupt, now is the time to
 172          * clear it.  NOTE: we assume the HT bridge was set up to
 173          * deliver the interrupts to all CPUs (which makes affinity
 174          * changing easier for us)
 175          */
 176         pending = __raw_readq(IOADDR(A_IMR_REGISTER(sb1250_irq_owner[irq],
 177                                                     R_IMR_LDT_INTERRUPT)));
 178         pending &= ((u64)1 << (irq));
 179         if (pending) {
 180                 int i;
 181                 for (i=0; i<NR_CPUS; i++) {
 182                         int cpu;
 183 #ifdef CONFIG_SMP
 184                         cpu = cpu_logical_map(i);
 185 #else
 186                         cpu = i;
 187 #endif
 188                         /*
 189                          * Clear for all CPUs so an affinity switch
 190                          * doesn't find an old status
 191                          */
 192                         __raw_writeq(pending,
 193                                      IOADDR(A_IMR_REGISTER(cpu,
 194                                                 R_IMR_LDT_INTERRUPT_CLR)));
 195                 }
 196
 197                 /*
 198                  * Generate EOI.  For Pass 1 parts, EOI is a nop.  For
 199                  * Pass 2, the LDT world may be edge-triggered, but
 200                  * this EOI shouldn't hurt.  If they are
 201                  * level-sensitive, the EOI is required.
 202                  */
 203                 *(uint32_t *)(ldt_eoi_space+(irq<<16)+(7<<2)) = 0;
 204         }
 205 #endif
 206         sb1250_mask_irq(sb1250_irq_owner[irq], irq);
 207 }
 208
 209
 210 static void end_sb1250_irq(unsigned int irq)
 211 {
 212         if (!(irq_desc[irq].status & (IRQ_DISABLED | IRQ_INPROGRESS))) {
 213                 sb1250_unmask_irq(sb1250_irq_owner[irq], irq);
 214         }
 215 }
 216
 217
 218 void __init init_sb1250_irqs(void)
 219 {
 220         int i;
 221
 222         for (i = 0; i < SB1250_NR_IRQS; i++) {
 223                 set_irq_chip_and_handler(i, &sb1250_irq_type, handle_level_irq);
 224                 sb1250_irq_owner[i] = 0;
 225         }
 226 }
 227
 228
 229 /*
 230  *  arch_init_irq is called early in the boot sequence from init/main.c via
 231  *  init_IRQ.  It is responsible for setting up the interrupt mapper and
 232  *  installing the handler that will be responsible for dispatching interrupts
 233  *  to the "right" place.
 234  */
 235 /*
 236  * For now, map all interrupts to IP[2].  We could save
 237  * some cycles by parceling out system interrupts to different
 238  * IP lines, but keep it simple for bringup.  We'll also direct
 239  * all interrupts to a single CPU; we should probably route
 240  * PCI and LDT to one cpu and everything else to the other
 241  * to balance the load a bit.
 242  *
 243  * On the second cpu, everything is set to IP5, which is
 244  * ignored, EXCEPT the mailbox interrupt.  That one is
 245  * set to IP[2] so it is handled.  This is needed so we
 246  * can do cross-cpu function calls, as requred by SMP
 247  */
 248
 249 #define IMR_IP2_VAL     K_INT_MAP_I0
 250 #define IMR_IP3_VAL     K_INT_MAP_I1
 251 #define IMR_IP4_VAL     K_INT_MAP_I2
 252 #define IMR_IP5_VAL     K_INT_MAP_I3
 253 #define IMR_IP6_VAL     K_INT_MAP_I4
 254
 255 void __init arch_init_irq(void)
 256 {
 257
 258         unsigned int i;
 259         u64 tmp;
 260         unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 261                 STATUSF_IP1 | STATUSF_IP0;
 262
 263         /* Default everything to IP2 */
 264         for (i = 0; i < SB1250_NR_IRQS; i++) {  /* was I0 */
 265                 __raw_writeq(IMR_IP2_VAL,
 266                              IOADDR(A_IMR_REGISTER(0,
 267                                                    R_IMR_INTERRUPT_MAP_BASE) +
 268                                     (i << 3)));
 269                 __raw_writeq(IMR_IP2_VAL,
 270                              IOADDR(A_IMR_REGISTER(1,
 271                                                    R_IMR_INTERRUPT_MAP_BASE) +
 272                                     (i << 3)));
 273         }
 274
 275         init_sb1250_irqs();
 276
 277         /*
 278          * Map the high 16 bits of the mailbox registers to IP[3], for
 279          * inter-cpu messages
 280          */
 281         /* Was I1 */
 282         __raw_writeq(IMR_IP3_VAL,
 283                      IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MAP_BASE) +
 284                             (K_INT_MBOX_0 << 3)));
 285         __raw_writeq(IMR_IP3_VAL,
 286                      IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MAP_BASE) +
 287                             (K_INT_MBOX_0 << 3)));
 288
 289         /* Clear the mailboxes.  The firmware may leave them dirty */
 290         __raw_writeq(0xffffffffffffffffULL,
 291                      IOADDR(A_IMR_REGISTER(0, R_IMR_MAILBOX_CLR_CPU)));
 292         __raw_writeq(0xffffffffffffffffULL,
 293                      IOADDR(A_IMR_REGISTER(1, R_IMR_MAILBOX_CLR_CPU)));
 294
 295         /* Mask everything except the mailbox registers for both cpus */
 296         tmp = ~((u64) 0) ^ (((u64) 1) << K_INT_MBOX_0);
 297         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(0, R_IMR_INTERRUPT_MASK)));
 298         __raw_writeq(tmp, IOADDR(A_IMR_REGISTER(1, R_IMR_INTERRUPT_MASK)));
 299
 300         /*
 301          * Note that the timer interrupts are also mapped, but this is
 302          * done in sb1250_time_init().  Also, the profiling driver
 303          * does its own management of IP7.
 304          */
 305
 306         /* Enable necessary IPs, disable the rest */
 307         change_c0_status(ST0_IM, imask);
 308 }
 309
 310 extern void sb1250_mailbox_interrupt(void);
 311
 312 static inline void dispatch_ip2(void)
 313 {
 314         unsigned int cpu = smp_processor_id();
 315         unsigned long long mask;
 316
 317         /*
 318          * Default...we've hit an IP[2] interrupt, which means we've got to
 319          * check the 1250 interrupt registers to figure out what to do.  Need
 320          * to detect which CPU we're on, now that smp_affinity is supported.
 321          */
 322         mask = __raw_readq(IOADDR(A_IMR_REGISTER(cpu,
 323                                   R_IMR_INTERRUPT_STATUS_BASE)));
 324         if (mask)
 325                 do_IRQ(fls64(mask) - 1);
 326 }
 327
 328 asmlinkage void plat_irq_dispatch(void)
 329 {
 330         unsigned int cpu = smp_processor_id();
 331         unsigned int pending;
 332
 333         /*
 334          * What a pain. We have to be really careful saving the upper 32 bits
 335          * of any * register across function calls if we don't want them
 336          * trashed--since were running in -o32, the calling routing never saves
 337          * the full 64 bits of a register across a function call.  Being the
 338          * interrupt handler, we're guaranteed that interrupts are disabled
 339          * during this code so we don't have to worry about random interrupts
 340          * blasting the high 32 bits.
 341          */
 342
 343         pending = read_c0_cause() & read_c0_status() & ST0_IM;
 344
 345         if (pending & CAUSEF_IP7) /* CPU performance counter interrupt */
 346                 do_IRQ(MIPS_CPU_IRQ_BASE + 7);
 347         else if (pending & CAUSEF_IP4)
 348                 do_IRQ(K_INT_TIMER_0 + cpu);    /* sb1250_timer_interrupt() */
 349
 350 #ifdef CONFIG_SMP
 351         else if (pending & CAUSEF_IP3)
 352                 sb1250_mailbox_interrupt();
 353 #endif
 354
 355         else if (pending & CAUSEF_IP2)
 356                 dispatch_ip2();
 357         else
 358                 spurious_interrupt();
 359 }