arch/mips/baget/irq.c

   1 /*
   2  * Code to handle Baget/MIPS IRQs plus some generic interrupt stuff.
   3  *
   4  * Copyright (C) 1998 Vladimir Roganov & Gleb Raiko
   5  *      Code (mostly sleleton and comments) derived from DECstation IRQ
   6  *      handling.
   7  */
   8 #include <linux/errno.h>
   9 #include <linux/init.h>
  10 #include <linux/kernel_stat.h>
  11 #include <linux/module.h>
  12 #include <linux/signal.h>
  13 #include <linux/sched.h>
  14 #include <linux/types.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/ioport.h>
  17 #include <linux/timex.h>
  18 #include <linux/slab.h>
  19 #include <linux/random.h>
  20 #include <linux/delay.h>
  21
  22 #include <asm/bitops.h>
  23 #include <asm/bootinfo.h>
  24 #include <asm/io.h>
  25 #include <asm/irq.h>
  26 #include <asm/mipsregs.h>
  27 #include <asm/system.h>
  28
  29 #include <asm/baget/baget.h>
  30
  31 volatile unsigned long irq_err_count;
  32
  33 /*
  34  * This table is a correspondence between IRQ numbers and CPU PILs
  35  */
  36
  37 static int irq_to_pil_map[BAGET_IRQ_NR] = {
  38         7/*fixme: dma_err -1*/,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1, /* 0x00 - 0x0f */
  39         -1,-1,-1,-1, 3,-1,-1,-1, 2, 2, 2,-1, 3,-1,-1,3/*fixme: lance*/, /* 0x10 - 0x1f */
  40         -1,-1,-1,-1,-1,-1, 5,-1,-1,-1,-1,-1, 7,-1,-1,-1, /* 0x20 - 0x2f */
  41         -1, 3, 2/*fixme systimer:3*/, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3  /* 0x30 - 0x3f */
  42 };
  43
  44 static inline int irq_to_pil(int irq_nr)
  45 {
  46         int pil = -1;
  47
  48         if (irq_nr >= BAGET_IRQ_NR)
  49                 baget_printk("irq_to_pil: too large irq_nr = 0x%x\n", irq_nr);
  50         else {
  51                 pil = irq_to_pil_map[irq_nr];
  52                 if (pil == -1)
  53                         baget_printk("irq_to_pil: unknown irq = 0x%x\n", irq_nr);
  54         }
  55
  56         return pil;
  57 }
  58
  59 /* Function for careful CP0 interrupt mask access */
  60
  61 static inline void modify_cp0_intmask(unsigned clr_mask, unsigned set_mask)
  62 {
  63         unsigned long status = read_c0_status();
  64         status &= ~((clr_mask & 0xFF) << 8);
  65         status |=   (set_mask & 0xFF) << 8;
  66         write_c0_status(status);
  67 }
  68
  69 /*
  70  *  These two functions may be used for unconditional IRQ
  71  *  masking via their PIL protection.
  72  */
  73
  74 static inline void mask_irq(unsigned int irq_nr)
  75 {
  76         modify_cp0_intmask(irq_to_pil(irq_nr), 0);
  77 }
  78
  79 static inline void unmask_irq(unsigned int irq_nr)
  80 {
  81         modify_cp0_intmask(0, irq_to_pil(irq_nr));
  82 }
  83
  84 /*
  85  * The following section is introduced for masking/unasking IRQ
  86  * only while no more IRQs uses same CPU PIL.
  87  *
  88  * These functions are used in request_irq, free_irq, but it looks
  89  * they cannot change something: CP0_STATUS is private for any
  90  * process, and their action is invisible for system.
  91  */
  92
  93 static volatile unsigned int pil_in_use[BAGET_PIL_NR] = { 0, };
  94
  95 void mask_irq_count(int irq_nr)
  96 {
  97         unsigned long flags;
  98         int pil = irq_to_pil(irq_nr);
  99
 100         local_irq_save(flags);
 101         if (!--pil_in_use[pil])
 102                 mask_irq(irq_nr);
 103         local_irq_restore(flags);
 104 }
 105
 106 void unmask_irq_count(int irq_nr)
 107 {
 108         unsigned long flags;
 109         int pil = irq_to_pil(irq_nr);
 110
 111         local_irq_save(flags);
 112         if (!pil_in_use[pil]++)
 113                 unmask_irq(irq_nr);
 114         local_irq_restore(flags);
 115 }
 116
 117 /*
 118  * Two functions below are exported versions of mask/unmask IRQ
 119  */
 120
 121 void disable_irq(unsigned int irq_nr)
 122 {
 123         unsigned long flags;
 124
 125         local_irq_save(flags);
 126         mask_irq(irq_nr);
 127         local_irq_restore(flags);
 128 }
 129
 130 void enable_irq(unsigned int irq_nr)
 131 {
 132         unsigned long flags;
 133
 134         local_irq_save(flags);
 135         unmask_irq(irq_nr);
 136         local_irq_restore(flags);
 137 }
 138
 139 /*
 140  * Pointers to the low-level handlers: first the general ones, then the
 141  * fast ones, then the bad ones.
 142  */
 143 static struct irqaction *irq_action[BAGET_IRQ_NR] = { NULL, };
 144
 145 int get_irq_list(char *buf)
 146 {
 147         int i, len = 0;
 148         struct irqaction * action;
 149         unsigned long flags;
 150
 151         for (i = 0 ; i < BAGET_IRQ_NR ; i++) {
 152                 local_irq_save(flags);
 153                 action = irq_action[i];
 154                 if (!action)
 155                         gotos skip;
 156                 len += sprintf(buf+len, "%2d: %8d %c %s",
 157                         i, kstat_this_cpu.irqs[i],
 158                         (action->flags & SA_INTERRUPT) ? '+' : ' ',
 159                         action->name);
 160                 for (action=action->next; action; action = action->next) {
 161                         len += sprintf(buf+len, ",%s %s",
 162                                 (action->flags & SA_INTERRUPT) ? " +" : "",
 163                                 action->name);
 164                 }
 165                 len += sprintf(buf+len, "\n");
 166 skip:
 167                 local_irq_restore(flags);
 168         }
 169         return len;
 170 }
 171
 172
 173 /*
 174  * do_IRQ handles IRQ's that have been installed without the
 175  * SA_INTERRUPT flag: it uses the full signal-handling return
 176  * and runs with other interrupts enabled. All relatively slow
 177  * IRQ's should use this format: notably the keyboard/timer
 178  * routines.
 179  */
 180 static void do_IRQ(int irq, struct pt_regs * regs)
 181 {
 182         struct irqaction *action;
 183         int do_random, cpu;
 184
 185         cpu = smp_processor_id();
 186         irq_enter();
 187         kstat_cpus(cpu).irqs[irq]++;
 188
 189         mask_irq(irq);
 190         action = *(irq + irq_action);
 191         if (action) {
 192                 if (!(action->flags & SA_INTERRUPT))
 193                         local_irq_enable();
 194                 action = *(irq + irq_action);
 195                 do_random = 0;
 196                 do {
 197                         do_random |= action->flags;
 198                         action->handler(irq, action->dev_id, regs);
 199                         action = action->next;
 200                 } while (action);
 201                 if (do_random & SA_SAMPLE_RANDOM)
 202                         add_interrupt_randomness(irq);
 203                 local_irq_disable();
 204         } else {
 205                 printk("do_IRQ: Unregistered IRQ (0x%X) occurred\n", irq);
 206         }
 207         unmask_irq(irq);
 208         irq_exit();
 209
 210         /* unmasking and bottom half handling is done magically for us. */
 211 }
 212
 213 /*
 214  *  What to do in case of 'no VIC register available' for current interrupt
 215  */
 216 static void vic_reg_error(unsigned long address, unsigned char active_pils)
 217 {
 218         printk("\nNo VIC register found: reg=%08lx active_pils=%02x\n"
 219                "Current interrupt mask from CP0_CAUSE: %02x\n",
 220                address, 0xff & active_pils,
 221                0xff & (read_c0_cause()>>8));
 222         { int i; for (i=0; i<10000; i++) udelay(1000); }
 223 }
 224
 225 static char baget_fpu_irq = BAGET_FPU_IRQ;
 226 #define BAGET_INT_FPU {(unsigned long)&baget_fpu_irq, 1}
 227
 228 /*
 229  *  Main interrupt handler: interrupt demultiplexer
 230  */
 231 asmlinkage void baget_interrupt(struct pt_regs *regs)
 232 {
 233         static struct baget_int_reg int_reg[BAGET_PIL_NR] = {
 234                 BAGET_INT_NONE, BAGET_INT_NONE, BAGET_INT0_ACK, BAGET_INT1_ACK,
 235                 BAGET_INT_NONE, BAGET_INT_FPU,  BAGET_INT_NONE, BAGET_INT5_ACK
 236         };
 237         unsigned char active_pils;
 238         while ((active_pils = read_c0_cause()>>8)) {
 239                 int pil;
 240                 struct baget_int_reg* reg;
 241
 242                 for (pil = 0; pil < BAGET_PIL_NR; pil++) {
 243                         if (!(active_pils & (1<<pil))) continue;
 244
 245                         reg = &int_reg[pil];
 246
 247                         if (reg->address) {
 248                                 extern int try_read(unsigned long,int);
 249                                 int irq  = try_read(reg->address, reg->size);
 250
 251                                 if (irq != -1)
 252                                       do_IRQ(BAGET_IRQ_MASK(irq), regs);
 253                                 else
 254                                       vic_reg_error(reg->address, active_pils);
 255                         } else {
 256                                 printk("baget_interrupt: unknown interrupt "
 257                                        "(pil = %d)\n", pil);
 258                         }
 259                 }
 260         }
 261 }
 262
 263 /*
 264  * Idea is to put all interrupts
 265  * in a single table and differenciate them just by number.
 266  */
 267 int setup_baget_irq(int irq, struct irqaction * new)
 268 {
 269         int shared = 0;
 270         struct irqaction *old, **p;
 271         unsigned long flags;
 272
 273         p = irq_action + irq;
 274         if ((old = *p) != NULL) {
 275                 /* Can't share interrupts unless both agree to */
 276                 if (!(old->flags & new->flags & SA_SHIRQ))
 277                         return -EBUSY;
 278
 279                 /* Can't share interrupts unless both are same type */
 280                 if ((old->flags ^ new->flags) & SA_INTERRUPT)
 281                         return -EBUSY;
 282
 283                 /* add new interrupt at end of irq queue */
 284                 do {
 285                         p = &old->next;
 286                         old = *p;
 287                 } while (old);
 288                 shared = 1;
 289         }
 290
 291         if (new->flags & SA_SAMPLE_RANDOM)
 292                 rand_initialize_irq(irq);
 293
 294         local_irq_save(flags);
 295         *p = new;
 296         local_irq_restore(flags);
 297
 298         if (!shared) {
 299                 unmask_irq_count(irq);
 300         }
 301
 302         return 0;
 303 }
 304
 305 int request_irq(unsigned int irq,
 306                 void (*handler)(int, void *, struct pt_regs *),
 307                 unsigned long irqflags,
 308                 const char * devname,
 309                 void *dev_id)
 310 {
 311         int retval;
 312         struct irqaction * action;
 313
 314         if (irq >= BAGET_IRQ_NR)
 315                 return -EINVAL;
 316         if (!handler)
 317                 return -EINVAL;
 318         if (irq_to_pil_map[irq] < 0)
 319                 return -EINVAL;
 320
 321         action = (struct irqaction *)
 322                         kmalloc(sizeof(struct irqaction), GFP_KERNEL);
 323         if (!action)
 324                 return -ENOMEM;
 325
 326         action->handler = handler;
 327         action->flags = irqflags;
 328         action->mask = 0;
 329         action->name = devname;
 330         action->next = NULL;
 331         action->dev_id = dev_id;
 332
 333         retval = setup_baget_irq(irq, action);
 334
 335         if (retval)
 336                 kfree(action);
 337
 338         return retval;
 339 }
 340
 341 EXPORT_SYMBOL(request_irq);
 342
 343 void free_irq(unsigned int irq, void *dev_id)
 344 {
 345         struct irqaction * action, **p;
 346         unsigned long flags;
 347
 348         if (irq >= BAGET_IRQ_NR)
 349                 printk("Trying to free IRQ%d\n",irq);
 350
 351         for (p = irq + irq_action; (action = *p) != NULL; p = &action->next) {
 352                 if (action->dev_id != dev_id)
 353                         continue;
 354
 355                 /* Found it - now free it */
 356                 local_irq_save(flags);
 357                 *p = action->next;
 358                 if (!irq[irq_action])
 359                         unmask_irq_count(irq);
 360                 local_irq_restore(flags);
 361                 kfree(action);
 362                 return;
 363         }
 364         printk("Trying to free free IRQ%d\n",irq);
 365 }
 366
 367 EXPORT_SYMBOL(free_irq);
 368
 369 unsigned long probe_irq_on (void)
 370 {
 371         /* TODO */
 372         return 0;
 373 }
 374
 375 EXPORT_SYMBOL(probe_irq_on);
 376
 377 int probe_irq_off (unsigned long irqs)
 378 {
 379         /* TODO */
 380         return 0;
 381 }
 382
 383 EXPORT_SYMBOL(probe_irq_off);
 384
 385
 386 static void write_err_interrupt(int irq, void *dev_id, struct pt_regs * regs)
 387 {
 388         *(volatile char*) BAGET_WRERR_ACK = 0;
 389 }
 390
 391 static struct irqaction irq0  =
 392 { write_err_interrupt, SA_INTERRUPT, 0, "bus write error", NULL, NULL};
 393
 394 void __init init_IRQ(void)
 395 {
 396         irq_setup();
 397
 398         /* Enable access to VIC interrupt registers */
 399         vac_outw(0xacef | 0x8200, VAC_PIO_FUNC);
 400
 401         /* Enable interrupts for pils 2 and 3 (lines 0 and 1) */
 402         modify_cp0_intmask(0, (1<<2)|(1<<3));
 403
 404         if (setup_baget_irq(0, &irq0) < 0)
 405                 printk("init_IRQ: unable to register write_err irq\n");
 406 }