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