arch/m68k/atari/ataints.c

   1 /*
   2  * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code
   3  *
   4  * 5/2/94 Roman Hodek:
   5  *  Added support for TT interrupts; setup for TT SCU (may someone has
   6  *  twiddled there and we won't get the right interrupts :-()
   7  *
   8  *  Major change: The device-independent code in m68k/ints.c didn't know
   9  *  about non-autovec ints yet. It hardcoded the number of possible ints to
  10  *  7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the
  11  *  number of possible ints a constant defined in interrupt.h, which is
  12  *  47 for the Atari. So we can call request_irq() for all Atari interrupts
  13  *  just the normal way. Additionally, all vectors >= 48 are initialized to
  14  *  call trap() instead of inthandler(). This must be changed here, too.
  15  *
  16  * 1995-07-16 Lars Brinkhoff <f93labr@dd.chalmers.se>:
  17  *  Corrected a bug in atari_add_isr() which rejected all SCC
  18  *  interrupt sources if there were no TT MFP!
  19  *
  20  * 12/13/95: New interface functions atari_level_triggered_int() and
  21  *  atari_register_vme_int() as support for level triggered VME interrupts.
  22  *
  23  * 02/12/96: (Roman)
  24  *  Total rewrite of Atari interrupt handling, for new scheme see comments
  25  *  below.
  26  *
  27  * 1996-09-03 lars brinkhoff <f93labr@dd.chalmers.se>:
  28  *  Added new function atari_unregister_vme_int(), and
  29  *  modified atari_register_vme_int() as well as IS_VALID_INTNO()
  30  *  to work with it.
  31  *
  32  * This file is subject to the terms and conditions of the GNU General Public
  33  * License.  See the file COPYING in the main directory of this archive
  34  * for more details.
  35  *
  36  */
  37
  38 #include <linux/types.h>
  39 #include <linux/kernel.h>
  40 #include <linux/kernel_stat.h>
  41 #include <linux/init.h>
  42 #include <linux/seq_file.h>
  43 #include <linux/module.h>
  44
  45 #include <asm/system.h>
  46 #include <asm/traps.h>
  47
  48 #include <asm/atarihw.h>
  49 #include <asm/atariints.h>
  50 #include <asm/atari_stdma.h>
  51 #include <asm/irq.h>
  52 #include <asm/entry.h>
  53
  54
  55 /*
  56  * Atari interrupt handling scheme:
  57  * --------------------------------
  58  *
  59  * All interrupt source have an internal number (defined in
  60  * <asm/atariints.h>): Autovector interrupts are 1..7, then follow ST-MFP,
  61  * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can
  62  * be allocated by atari_register_vme_int().
  63  *
  64  * Each interrupt can be of three types:
  65  *
  66  *  - SLOW: The handler runs with all interrupts enabled, except the one it
  67  *    was called by (to avoid reentering). This should be the usual method.
  68  *    But it is currently possible only for MFP ints, since only the MFP
  69  *    offers an easy way to mask interrupts.
  70  *
  71  *  - FAST: The handler runs with all interrupts disabled. This should be used
  72  *    only for really fast handlers, that just do actions immediately
  73  *    necessary, and let the rest do a bottom half or task queue.
  74  *
  75  *  - PRIORITIZED: The handler can be interrupted by higher-level ints
  76  *    (greater IPL, no MFP priorities!). This is the method of choice for ints
  77  *    which should be slow, but are not from a MFP.
  78  *
  79  * The feature of more than one handler for one int source is still there, but
  80  * only applicable if all handers are of the same type. To not slow down
  81  * processing of ints with only one handler by the chaining feature, the list
  82  * calling function atari_call_irq_list() is only plugged in at the time the
  83  * second handler is registered.
  84  *
  85  * Implementation notes: For fast-as-possible int handling, there are separate
  86  * entry points for each type (slow/fast/prio). The assembler handler calls
  87  * the irq directly in the usual case, no C wrapper is involved. In case of
  88  * multiple handlers, atari_call_irq_list() is registered as handler and calls
  89  * in turn the real irq's. To ease access from assembler level to the irq
  90  * function pointer and accompanying data, these two are stored in a separate
  91  * array, irq_handler[]. The rest of data (type, name) are put into a second
  92  * array, irq_param, that is accessed from C only. For each slow interrupt (32
  93  * in all) there are separate handler functions, which makes it possible to
  94  * hard-code the MFP register address and value, are necessary to mask the
  95  * int. If there'd be only one generic function, lots of calculations would be
  96  * needed to determine MFP register and int mask from the vector number :-(
  97  *
  98  * Furthermore, slow ints may not lower the IPL below its previous value
  99  * (before the int happened). This is needed so that an int of class PRIO, on
 100  * that this int may be stacked, cannot be reentered. This feature is
 101  * implemented as follows: If the stack frame format is 1 (throwaway), the int
 102  * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level
 103  * 2, which still blocks the HSYNC, but no interrupts of interest. If the
 104  * frame format is 0, the int is nested, and the old IPL value can be found in
 105  * the sr copy in the frame.
 106  */
 107
 108 #if 0
 109
 110 #define NUM_INT_SOURCES (8 + NUM_ATARI_SOURCES)
 111
 112 typedef void (*asm_irq_handler)(void);
 113
 114 struct irqhandler {
 115         irqreturn_t (*handler)(int, void *, struct pt_regs *);
 116         void    *dev_id;
 117 };
 118
 119 struct irqparam {
 120         unsigned long   flags;
 121         const char      *devname;
 122 };
 123
 124 /*
 125  * Array with irq's and their parameter data. This array is accessed from low
 126  * level assembler code, so an element size of 8 allows usage of index scaling
 127  * addressing mode.
 128  */
 129 static struct irqhandler irq_handler[NUM_INT_SOURCES];
 130
 131 /*
 132  * This array hold the rest of parameters of int handlers: type
 133  * (slow,fast,prio) and the name of the handler. These values are only
 134  * accessed from C
 135  */
 136 static struct irqparam irq_param[NUM_INT_SOURCES];
 137
 138 /* check for valid int number (complex, sigh...) */
 139 #define IS_VALID_INTNO(n)                                                                                       \
 140         ((n) > 0 &&                                                                                                             \
 141          /* autovec and ST-MFP ok anyway */                                                             \
 142          (((n) < TTMFP_SOURCE_BASE) ||                                                                  \
 143           /* TT-MFP ok if present */                                                                    \
 144           ((n) >= TTMFP_SOURCE_BASE && (n) < SCC_SOURCE_BASE &&                 \
 145            ATARIHW_PRESENT(TT_MFP)) ||                                                                  \
 146           /* SCC ok if present and number even */                                               \
 147           ((n) >= SCC_SOURCE_BASE && (n) < VME_SOURCE_BASE &&                   \
 148            !((n) & 1) && ATARIHW_PRESENT(SCC)) ||                                               \
 149           /* greater numbers ok if they are registered VME vectors */           \
 150           ((n) >= VME_SOURCE_BASE && (n) < VME_SOURCE_BASE + VME_MAX_SOURCES && \
 151                   free_vme_vec_bitmap & (1 << ((n) - VME_SOURCE_BASE)))))
 152
 153
 154 /*
 155  * Here start the assembler entry points for interrupts
 156  */
 157
 158 #define IRQ_NAME(nr) atari_slow_irq_##nr##_handler(void)
 159
 160 #define BUILD_SLOW_IRQ(n)                                                  \
 161 asmlinkage void IRQ_NAME(n);                                               \
 162 /* Dummy function to allow asm with operands.  */                          \
 163 void atari_slow_irq_##n##_dummy (void) {                                   \
 164 __asm__ (__ALIGN_STR "\n"                                                  \
 165 "atari_slow_irq_" #n "_handler:\t"                                         \
 166 "       addl    %6,%5\n"        /* preempt_count() += HARDIRQ_OFFSET */    \
 167         SAVE_ALL_INT "\n"                                                  \
 168         GET_CURRENT(%%d0) "\n"                                             \
 169 "       andb    #~(1<<(%c3&7)),%a4:w\n" /* mask this interrupt */          \
 170         /* get old IPL from stack frame */                                 \
 171 "       bfextu  %%sp@(%c2){#5,#3},%%d0\n"                                  \
 172 "       movew   %%sr,%%d1\n"                                               \
 173 "       bfins   %%d0,%%d1{#21,#3}\n"                                       \
 174 "       movew   %%d1,%%sr\n"            /* set IPL = previous value */     \
 175 "       addql   #1,%a0\n"                                                  \
 176 "       lea     %a1,%%a0\n"                                                \
 177 "       pea     %%sp@\n"                /* push addr of frame */           \
 178 "       movel   %%a0@(4),%%sp@-\n"      /* push handler data */            \
 179 "       pea     (%c3+8)\n"              /* push int number */              \
 180 "       movel   %%a0@,%%a0\n"                                              \
 181 "       jbsr    %%a0@\n"                /* call the handler */             \
 182 "       addql   #8,%%sp\n"                                                 \
 183 "       addql   #4,%%sp\n"                                                 \
 184 "       orw     #0x0600,%%sr\n"                                            \
 185 "       andw    #0xfeff,%%sr\n"         /* set IPL = 6 again */            \
 186 "       orb     #(1<<(%c3&7)),%a4:w\n"  /* now unmask the int again */     \
 187 "       jbra    ret_from_interrupt\n"                                      \
 188          : : "i" (&kstat_cpu(0).irqs[n+8]), "i" (&irq_handler[n+8]),       \
 189              "n" (PT_OFF_SR), "n" (n),                                     \
 190              "i" (n & 8 ? (n & 16 ? &tt_mfp.int_mk_a : &st_mfp.int_mk_a)   \
 191                         : (n & 16 ? &tt_mfp.int_mk_b : &st_mfp.int_mk_b)), \
 192              "m" (preempt_count()), "di" (HARDIRQ_OFFSET)                  \
 193 );                                                                         \
 194         for (;;);                       /* fake noreturn */                \
 195 }
 196
 197 BUILD_SLOW_IRQ(0);
 198 BUILD_SLOW_IRQ(1);
 199 BUILD_SLOW_IRQ(2);
 200 BUILD_SLOW_IRQ(3);
 201 BUILD_SLOW_IRQ(4);
 202 BUILD_SLOW_IRQ(5);
 203 BUILD_SLOW_IRQ(6);
 204 BUILD_SLOW_IRQ(7);
 205 BUILD_SLOW_IRQ(8);
 206 BUILD_SLOW_IRQ(9);
 207 BUILD_SLOW_IRQ(10);
 208 BUILD_SLOW_IRQ(11);
 209 BUILD_SLOW_IRQ(12);
 210 BUILD_SLOW_IRQ(13);
 211 BUILD_SLOW_IRQ(14);
 212 BUILD_SLOW_IRQ(15);
 213 BUILD_SLOW_IRQ(16);
 214 BUILD_SLOW_IRQ(17);
 215 BUILD_SLOW_IRQ(18);
 216 BUILD_SLOW_IRQ(19);
 217 BUILD_SLOW_IRQ(20);
 218 BUILD_SLOW_IRQ(21);
 219 BUILD_SLOW_IRQ(22);
 220 BUILD_SLOW_IRQ(23);
 221 BUILD_SLOW_IRQ(24);
 222 BUILD_SLOW_IRQ(25);
 223 BUILD_SLOW_IRQ(26);
 224 BUILD_SLOW_IRQ(27);
 225 BUILD_SLOW_IRQ(28);
 226 BUILD_SLOW_IRQ(29);
 227 BUILD_SLOW_IRQ(30);
 228 BUILD_SLOW_IRQ(31);
 229
 230 asm_irq_handler slow_handlers[32] = {
 231         [0]     = atari_slow_irq_0_handler,
 232         [1]     = atari_slow_irq_1_handler,
 233         [2]     = atari_slow_irq_2_handler,
 234         [3]     = atari_slow_irq_3_handler,
 235         [4]     = atari_slow_irq_4_handler,
 236         [5]     = atari_slow_irq_5_handler,
 237         [6]     = atari_slow_irq_6_handler,
 238         [7]     = atari_slow_irq_7_handler,
 239         [8]     = atari_slow_irq_8_handler,
 240         [9]     = atari_slow_irq_9_handler,
 241         [10]    = atari_slow_irq_10_handler,
 242         [11]    = atari_slow_irq_11_handler,
 243         [12]    = atari_slow_irq_12_handler,
 244         [13]    = atari_slow_irq_13_handler,
 245         [14]    = atari_slow_irq_14_handler,
 246         [15]    = atari_slow_irq_15_handler,
 247         [16]    = atari_slow_irq_16_handler,
 248         [17]    = atari_slow_irq_17_handler,
 249         [18]    = atari_slow_irq_18_handler,
 250         [19]    = atari_slow_irq_19_handler,
 251         [20]    = atari_slow_irq_20_handler,
 252         [21]    = atari_slow_irq_21_handler,
 253         [22]    = atari_slow_irq_22_handler,
 254         [23]    = atari_slow_irq_23_handler,
 255         [24]    = atari_slow_irq_24_handler,
 256         [25]    = atari_slow_irq_25_handler,
 257         [26]    = atari_slow_irq_26_handler,
 258         [27]    = atari_slow_irq_27_handler,
 259         [28]    = atari_slow_irq_28_handler,
 260         [29]    = atari_slow_irq_29_handler,
 261         [30]    = atari_slow_irq_30_handler,
 262         [31]    = atari_slow_irq_31_handler
 263 };
 264
 265 asmlinkage void atari_fast_irq_handler( void );
 266 asmlinkage void atari_prio_irq_handler( void );
 267
 268 /* Dummy function to allow asm with operands.  */
 269 void atari_fast_prio_irq_dummy (void) {
 270 __asm__ (__ALIGN_STR "\n"
 271 "atari_fast_irq_handler:\n\t"
 272         "orw    #0x700,%%sr\n"          /* disable all interrupts */
 273 "atari_prio_irq_handler:\n\t"
 274         "addl   %3,%2\n\t"              /* preempt_count() += HARDIRQ_OFFSET */
 275         SAVE_ALL_INT "\n\t"
 276         GET_CURRENT(%%d0) "\n\t"
 277         /* get vector number from stack frame and convert to source */
 278         "bfextu %%sp@(%c1){#4,#10},%%d0\n\t"
 279         "subw   #(0x40-8),%%d0\n\t"
 280         "jpl    1f\n\t"
 281         "addw   #(0x40-8-0x18),%%d0\n"
 282     "1:\tlea    %a0,%%a0\n\t"
 283         "addql  #1,%%a0@(%%d0:l:4)\n\t"
 284         "lea    irq_handler,%%a0\n\t"
 285         "lea    %%a0@(%%d0:l:8),%%a0\n\t"
 286         "pea    %%sp@\n\t"              /* push frame address */
 287         "movel  %%a0@(4),%%sp@-\n\t"    /* push handler data */
 288         "movel  %%d0,%%sp@-\n\t"        /* push int number */
 289         "movel  %%a0@,%%a0\n\t"
 290         "jsr    %%a0@\n\t"              /* and call the handler */
 291         "addql  #8,%%sp\n\t"
 292         "addql  #4,%%sp\n\t"
 293         "jbra   ret_from_interrupt"
 294          : : "i" (&kstat_cpu(0).irqs), "n" (PT_OFF_FORMATVEC),
 295              "m" (preempt_count()), "di" (HARDIRQ_OFFSET)
 296 );
 297         for (;;);
 298 }
 299 #endif
 300
 301 /*
 302  * Bitmap for free interrupt vector numbers
 303  * (new vectors starting from 0x70 can be allocated by
 304  * atari_register_vme_int())
 305  */
 306 static int free_vme_vec_bitmap;
 307
 308 /* GK:
 309  * HBL IRQ handler for Falcon. Nobody needs it :-)
 310  * ++andreas: raise ipl to disable further HBLANK interrupts.
 311  */
 312 asmlinkage void falcon_hblhandler(void);
 313 asm(".text\n"
 314 __ALIGN_STR "\n\t"
 315 "falcon_hblhandler:\n\t"
 316         "orw    #0x200,%sp@\n\t"        /* set saved ipl to 2 */
 317         "rte");
 318
 319 extern void atari_microwire_cmd(int cmd);
 320
 321 extern int atari_SCC_reset_done;
 322
 323 static int atari_startup_irq(unsigned int irq)
 324 {
 325         m68k_irq_startup(irq);
 326         atari_turnon_irq(irq);
 327         atari_enable_irq(irq);
 328         return 0;
 329 }
 330
 331 static void atari_shutdown_irq(unsigned int irq)
 332 {
 333         atari_disable_irq(irq);
 334         atari_turnoff_irq(irq);
 335         m68k_irq_shutdown(irq);
 336
 337         if (irq == IRQ_AUTO_4)
 338             vectors[VEC_INT4] = falcon_hblhandler;
 339 }
 340
 341 static struct irq_controller atari_irq_controller = {
 342         .name           = "atari",
 343         .lock           = __SPIN_LOCK_UNLOCKED(atari_irq_controller.lock),
 344         .startup        = atari_startup_irq,
 345         .shutdown       = atari_shutdown_irq,
 346         .enable         = atari_enable_irq,
 347         .disable        = atari_disable_irq,
 348 };
 349
 350 /*
 351  * void atari_init_IRQ (void)
 352  *
 353  * Parameters:  None
 354  *
 355  * Returns:     Nothing
 356  *
 357  * This function should be called during kernel startup to initialize
 358  * the atari IRQ handling routines.
 359  */
 360
 361 void __init atari_init_IRQ(void)
 362 {
 363         m68k_setup_user_interrupt(VEC_USER, NUM_ATARI_SOURCES - IRQ_USER, NULL);
 364         m68k_setup_irq_controller(&atari_irq_controller, 1, NUM_ATARI_SOURCES - 1);
 365
 366         /* Initialize the MFP(s) */
 367
 368 #ifdef ATARI_USE_SOFTWARE_EOI
 369         st_mfp.vec_adr  = 0x48; /* Software EOI-Mode */
 370 #else
 371         st_mfp.vec_adr  = 0x40; /* Automatic EOI-Mode */
 372 #endif
 373         st_mfp.int_en_a = 0x00; /* turn off MFP-Ints */
 374         st_mfp.int_en_b = 0x00;
 375         st_mfp.int_mk_a = 0xff; /* no Masking */
 376         st_mfp.int_mk_b = 0xff;
 377
 378         if (ATARIHW_PRESENT(TT_MFP)) {
 379 #ifdef ATARI_USE_SOFTWARE_EOI
 380                 tt_mfp.vec_adr  = 0x58;         /* Software EOI-Mode */
 381 #else
 382                 tt_mfp.vec_adr  = 0x50;         /* Automatic EOI-Mode */
 383 #endif
 384                 tt_mfp.int_en_a = 0x00;         /* turn off MFP-Ints */
 385                 tt_mfp.int_en_b = 0x00;
 386                 tt_mfp.int_mk_a = 0xff;         /* no Masking */
 387                 tt_mfp.int_mk_b = 0xff;
 388         }
 389
 390         if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) {
 391                 scc.cha_a_ctrl = 9;
 392                 MFPDELAY();
 393                 scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */
 394         }
 395
 396         if (ATARIHW_PRESENT(SCU)) {
 397                 /* init the SCU if present */
 398                 tt_scu.sys_mask = 0x10;         /* enable VBL (for the cursor) and
 399                                                                          * disable HSYNC interrupts (who
 400                                                                          * needs them?)  MFP and SCC are
 401                                                                          * enabled in VME mask
 402                                                                          */
 403                 tt_scu.vme_mask = 0x60;         /* enable MFP and SCC ints */
 404         } else {
 405                 /* If no SCU and no Hades, the HSYNC interrupt needs to be
 406                  * disabled this way. (Else _inthandler in kernel/sys_call.S
 407                  * gets overruns)
 408                  */
 409
 410                 vectors[VEC_INT2] = falcon_hblhandler;
 411                 vectors[VEC_INT4] = falcon_hblhandler;
 412         }
 413
 414         if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) {
 415                 /* Initialize the LM1992 Sound Controller to enable
 416                    the PSG sound.  This is misplaced here, it should
 417                    be in an atasound_init(), that doesn't exist yet. */
 418                 atari_microwire_cmd(MW_LM1992_PSG_HIGH);
 419         }
 420
 421         stdma_init();
 422
 423         /* Initialize the PSG: all sounds off, both ports output */
 424         sound_ym.rd_data_reg_sel = 7;
 425         sound_ym.wd_data = 0xff;
 426 }
 427
 428
 429 /*
 430  * atari_register_vme_int() returns the number of a free interrupt vector for
 431  * hardware with a programmable int vector (probably a VME board).
 432  */
 433
 434 unsigned long atari_register_vme_int(void)
 435 {
 436         int i;
 437
 438         for (i = 0; i < 32; i++)
 439                 if ((free_vme_vec_bitmap & (1 << i)) == 0)
 440                         break;
 441
 442         if (i == 16)
 443                 return 0;
 444
 445         free_vme_vec_bitmap |= 1 << i;
 446         return VME_SOURCE_BASE + i;
 447 }
 448 EXPORT_SYMBOL(atari_register_vme_int);
 449
 450
 451 void atari_unregister_vme_int(unsigned long irq)
 452 {
 453         if (irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) {
 454                 irq -= VME_SOURCE_BASE;
 455                 free_vme_vec_bitmap &= ~(1 << irq);
 456         }
 457 }
 458 EXPORT_SYMBOL(atari_unregister_vme_int);
 459
 460