/* * arch/m68k/atari/ataints.c -- Atari Linux interrupt handling code * * 5/2/94 Roman Hodek: * Added support for TT interrupts; setup for TT SCU (may someone has * twiddled there and we won't get the right interrupts :-() * * Major change: The device-independent code in m68k/ints.c didn't know * about non-autovec ints yet. It hardcoded the number of possible ints to * 7 (IRQ1...IRQ7). But the Atari has lots of non-autovec ints! I made the * number of possible ints a constant defined in interrupt.h, which is * 47 for the Atari. So we can call request_irq() for all Atari interrupts * just the normal way. Additionally, all vectors >= 48 are initialized to * call trap() instead of inthandler(). This must be changed here, too. * * 1995-07-16 Lars Brinkhoff : * Corrected a bug in atari_add_isr() which rejected all SCC * interrupt sources if there were no TT MFP! * * 12/13/95: New interface functions atari_level_triggered_int() and * atari_register_vme_int() as support for level triggered VME interrupts. * * 02/12/96: (Roman) * Total rewrite of Atari interrupt handling, for new scheme see comments * below. * * 1996-09-03 lars brinkhoff : * Added new function atari_unregister_vme_int(), and * modified atari_register_vme_int() as well as IS_VALID_INTNO() * to work with it. * * This file is subject to the terms and conditions of the GNU General Public * License. See the file COPYING in the main directory of this archive * for more details. * */ #include #include #include #include #include #include #include #include #include #include #include #include /* * Atari interrupt handling scheme: * -------------------------------- * * All interrupt source have an internal number (defined in * ): Autovector interrupts are 1..7, then follow ST-MFP, * TT-MFP, SCC, and finally VME interrupts. Vector numbers for the latter can * be allocated by atari_register_vme_int(). * * Each interrupt can be of three types: * * - SLOW: The handler runs with all interrupts enabled, except the one it * was called by (to avoid reentering). This should be the usual method. * But it is currently possible only for MFP ints, since only the MFP * offers an easy way to mask interrupts. * * - FAST: The handler runs with all interrupts disabled. This should be used * only for really fast handlers, that just do actions immediately * necessary, and let the rest do a bottom half or task queue. * * - PRIORITIZED: The handler can be interrupted by higher-level ints * (greater IPL, no MFP priorities!). This is the method of choice for ints * which should be slow, but are not from a MFP. * * The feature of more than one handler for one int source is still there, but * only applicable if all handers are of the same type. To not slow down * processing of ints with only one handler by the chaining feature, the list * calling function atari_call_irq_list() is only plugged in at the time the * second handler is registered. * * Implementation notes: For fast-as-possible int handling, there are separate * entry points for each type (slow/fast/prio). The assembler handler calls * the irq directly in the usual case, no C wrapper is involved. In case of * multiple handlers, atari_call_irq_list() is registered as handler and calls * in turn the real irq's. To ease access from assembler level to the irq * function pointer and accompanying data, these two are stored in a separate * array, irq_handler[]. The rest of data (type, name) are put into a second * array, irq_param, that is accessed from C only. For each slow interrupt (32 * in all) there are separate handler functions, which makes it possible to * hard-code the MFP register address and value, are necessary to mask the * int. If there'd be only one generic function, lots of calculations would be * needed to determine MFP register and int mask from the vector number :-( * * Furthermore, slow ints may not lower the IPL below its previous value * (before the int happened). This is needed so that an int of class PRIO, on * that this int may be stacked, cannot be reentered. This feature is * implemented as follows: If the stack frame format is 1 (throwaway), the int * is not stacked, and the IPL is anded with 0xfbff, resulting in a new level * 2, which still blocks the HSYNC, but no interrupts of interest. If the * frame format is 0, the int is nested, and the old IPL value can be found in * the sr copy in the frame. */ /* * Bitmap for free interrupt vector numbers * (new vectors starting from 0x70 can be allocated by * atari_register_vme_int()) */ static int free_vme_vec_bitmap; /* GK: * HBL IRQ handler for Falcon. Nobody needs it :-) * ++andreas: raise ipl to disable further HBLANK interrupts. */ asmlinkage void falcon_hblhandler(void); asm(".text\n" __ALIGN_STR "\n\t" "falcon_hblhandler:\n\t" "orw #0x200,%sp@\n\t" /* set saved ipl to 2 */ "rte"); extern void atari_microwire_cmd(int cmd); extern int atari_SCC_reset_done; static int atari_startup_irq(unsigned int irq) { m68k_irq_startup(irq); atari_turnon_irq(irq); atari_enable_irq(irq); return 0; } static void atari_shutdown_irq(unsigned int irq) { atari_disable_irq(irq); atari_turnoff_irq(irq); m68k_irq_shutdown(irq); if (irq == IRQ_AUTO_4) vectors[VEC_INT4] = falcon_hblhandler; } static struct irq_controller atari_irq_controller = { .name = "atari", .lock = __SPIN_LOCK_UNLOCKED(atari_irq_controller.lock), .startup = atari_startup_irq, .shutdown = atari_shutdown_irq, .enable = atari_enable_irq, .disable = atari_disable_irq, }; /* * void atari_init_IRQ (void) * * Parameters: None * * Returns: Nothing * * This function should be called during kernel startup to initialize * the atari IRQ handling routines. */ void __init atari_init_IRQ(void) { m68k_setup_user_interrupt(VEC_USER, NUM_ATARI_SOURCES - IRQ_USER, NULL); m68k_setup_irq_controller(&atari_irq_controller, 1, NUM_ATARI_SOURCES - 1); /* Initialize the MFP(s) */ #ifdef ATARI_USE_SOFTWARE_EOI mfp.vec_adr = 0x48; /* Software EOI-Mode */ #else mfp.vec_adr = 0x40; /* Automatic EOI-Mode */ #endif mfp.int_en_a = 0x00; /* turn off MFP-Ints */ mfp.int_en_b = 0x00; mfp.int_mk_a = 0xff; /* no Masking */ mfp.int_mk_b = 0xff; if (ATARIHW_PRESENT(TT_MFP)) { #ifdef ATARI_USE_SOFTWARE_EOI tt_mfp.vec_adr = 0x58; /* Software EOI-Mode */ #else tt_mfp.vec_adr = 0x50; /* Automatic EOI-Mode */ #endif tt_mfp.int_en_a = 0x00; /* turn off MFP-Ints */ tt_mfp.int_en_b = 0x00; tt_mfp.int_mk_a = 0xff; /* no Masking */ tt_mfp.int_mk_b = 0xff; } if (ATARIHW_PRESENT(SCC) && !atari_SCC_reset_done) { scc.cha_a_ctrl = 9; MFPDELAY(); scc.cha_a_ctrl = (char) 0xc0; /* hardware reset */ } if (ATARIHW_PRESENT(SCU)) { /* init the SCU if present */ tt_scu.sys_mask = 0x10; /* enable VBL (for the cursor) and * disable HSYNC interrupts (who * needs them?) MFP and SCC are * enabled in VME mask */ tt_scu.vme_mask = 0x60; /* enable MFP and SCC ints */ } else { /* If no SCU and no Hades, the HSYNC interrupt needs to be * disabled this way. (Else _inthandler in kernel/sys_call.S * gets overruns) */ if (!MACH_IS_HADES) { vectors[VEC_INT2] = falcon_hblhandler; vectors[VEC_INT4] = falcon_hblhandler; } } if (ATARIHW_PRESENT(PCM_8BIT) && ATARIHW_PRESENT(MICROWIRE)) { /* Initialize the LM1992 Sound Controller to enable the PSG sound. This is misplaced here, it should be in an atasound_init(), that doesn't exist yet. */ atari_microwire_cmd(MW_LM1992_PSG_HIGH); } stdma_init(); /* Initialize the PSG: all sounds off, both ports output */ sound_ym.rd_data_reg_sel = 7; sound_ym.wd_data = 0xff; } /* * atari_register_vme_int() returns the number of a free interrupt vector for * hardware with a programmable int vector (probably a VME board). */ unsigned long atari_register_vme_int(void) { int i; for (i = 0; i < 32; i++) if ((free_vme_vec_bitmap & (1 << i)) == 0) break; if (i == 16) return 0; free_vme_vec_bitmap |= 1 << i; return VME_SOURCE_BASE + i; } void atari_unregister_vme_int(unsigned long irq) { if (irq >= VME_SOURCE_BASE && irq < VME_SOURCE_BASE + VME_MAX_SOURCES) { irq -= VME_SOURCE_BASE; free_vme_vec_bitmap &= ~(1 << irq); } }