LXR linux/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
 112typedef void (*asm_irq_handler)(void);
 113
 114struct irqhandler {
 115        irqreturn_t (*handler)(int, void *, struct pt_regs *);
 116        void    *dev_id;
 117};
 118
 119struct 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 */
 129static 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 */
 136static 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)                                                  \
 161asmlinkage void IRQ_NAME(n);                                               \
 162/* Dummy function to allow asm with operands.  */                          \
 163void 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
 197BUILD_SLOW_IRQ(0);
 198BUILD_SLOW_IRQ(1);
 199BUILD_SLOW_IRQ(2);
 200BUILD_SLOW_IRQ(3);
 201BUILD_SLOW_IRQ(4);
 202BUILD_SLOW_IRQ(5);
 203BUILD_SLOW_IRQ(6);
 204BUILD_SLOW_IRQ(7);
 205BUILD_SLOW_IRQ(8);
 206BUILD_SLOW_IRQ(9);
 207BUILD_SLOW_IRQ(10);
 208BUILD_SLOW_IRQ(11);
 209BUILD_SLOW_IRQ(12);
 210BUILD_SLOW_IRQ(13);
 211BUILD_SLOW_IRQ(14);
 212BUILD_SLOW_IRQ(15);
 213BUILD_SLOW_IRQ(16);
 214BUILD_SLOW_IRQ(17);
 215BUILD_SLOW_IRQ(18);
 216BUILD_SLOW_IRQ(19);
 217BUILD_SLOW_IRQ(20);
 218BUILD_SLOW_IRQ(21);
 219BUILD_SLOW_IRQ(22);
 220BUILD_SLOW_IRQ(23);
 221BUILD_SLOW_IRQ(24);
 222BUILD_SLOW_IRQ(25);
 223BUILD_SLOW_IRQ(26);
 224BUILD_SLOW_IRQ(27);
 225BUILD_SLOW_IRQ(28);
 226BUILD_SLOW_IRQ(29);
 227BUILD_SLOW_IRQ(30);
 228BUILD_SLOW_IRQ(31);
 229
 230asm_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
 265asmlinkage void atari_fast_irq_handler( void );
 266asmlinkage void atari_prio_irq_handler( void );
 267
 268/* Dummy function to allow asm with operands.  */
 269void 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 */
 306static 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 */
 312asmlinkage void falcon_hblhandler(void);
 313asm(".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
 319extern void atari_microwire_cmd(int cmd);
 320
 321extern int atari_SCC_reset_done;
 322
 323static 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
 331static 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
 341static 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
 361void __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
 434unsigned 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}
 448EXPORT_SYMBOL(atari_register_vme_int);
 449
 450
 451void 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}
 458EXPORT_SYMBOL(atari_unregister_vme_int);
 459
 460
 461