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Diffstat (limited to 'arch/mips/dec/int-handler.S')
| -rw-r--r-- | arch/mips/dec/int-handler.S | 311 |
1 files changed, 311 insertions, 0 deletions
diff --git a/arch/mips/dec/int-handler.S b/arch/mips/dec/int-handler.S new file mode 100644 index 000000000..011d1d678 --- /dev/null +++ b/arch/mips/dec/int-handler.S @@ -0,0 +1,311 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Copyright (C) 1995, 1996, 1997 Paul M. Antoine and Harald Koerfgen + * Copyright (C) 2000, 2001, 2002, 2003, 2005 Maciej W. Rozycki + * + * Written by Ralf Baechle and Andreas Busse, modified for DECstation + * support by Paul Antoine and Harald Koerfgen. + * + * completely rewritten: + * Copyright (C) 1998 Harald Koerfgen + * + * Rewritten extensively for controller-driven IRQ support + * by Maciej W. Rozycki. + */ + +#include <asm/addrspace.h> +#include <asm/asm.h> +#include <asm/mipsregs.h> +#include <asm/regdef.h> +#include <asm/stackframe.h> + +#include <asm/dec/interrupts.h> +#include <asm/dec/ioasic_addrs.h> +#include <asm/dec/ioasic_ints.h> +#include <asm/dec/kn01.h> +#include <asm/dec/kn02.h> +#include <asm/dec/kn02xa.h> +#include <asm/dec/kn03.h> + +#define KN02_CSR_BASE CKSEG1ADDR(KN02_SLOT_BASE + KN02_CSR) +#define KN02XA_IOASIC_BASE CKSEG1ADDR(KN02XA_SLOT_BASE + IOASIC_IOCTL) +#define KN03_IOASIC_BASE CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_IOCTL) + + .text + .set noreorder +/* + * plat_irq_dispatch: Interrupt handler for DECstations + * + * We follow the model in the Indy interrupt code by David Miller, where he + * says: a lot of complication here is taken away because: + * + * 1) We handle one interrupt and return, sitting in a loop + * and moving across all the pending IRQ bits in the cause + * register is _NOT_ the answer, the common case is one + * pending IRQ so optimize in that direction. + * + * 2) We need not check against bits in the status register + * IRQ mask, that would make this routine slow as hell. + * + * 3) Linux only thinks in terms of all IRQs on or all IRQs + * off, nothing in between like BSD spl() brain-damage. + * + * Furthermore, the IRQs on the DECstations look basically (barring + * software IRQs which we don't use at all) like... + * + * DS2100/3100's, aka kn01, aka Pmax: + * + * MIPS IRQ Source + * -------- ------ + * 0 Software (ignored) + * 1 Software (ignored) + * 2 SCSI + * 3 Lance Ethernet + * 4 DZ11 serial + * 5 RTC + * 6 Memory Controller & Video + * 7 FPU + * + * DS5000/200, aka kn02, aka 3max: + * + * MIPS IRQ Source + * -------- ------ + * 0 Software (ignored) + * 1 Software (ignored) + * 2 TurboChannel + * 3 RTC + * 4 Reserved + * 5 Memory Controller + * 6 Reserved + * 7 FPU + * + * DS5000/1xx's, aka kn02ba, aka 3min: + * + * MIPS IRQ Source + * -------- ------ + * 0 Software (ignored) + * 1 Software (ignored) + * 2 TurboChannel Slot 0 + * 3 TurboChannel Slot 1 + * 4 TurboChannel Slot 2 + * 5 TurboChannel Slot 3 (ASIC) + * 6 Halt button + * 7 FPU/R4k timer + * + * DS5000/2x's, aka kn02ca, aka maxine: + * + * MIPS IRQ Source + * -------- ------ + * 0 Software (ignored) + * 1 Software (ignored) + * 2 Periodic Interrupt (100usec) + * 3 RTC + * 4 I/O write timeout + * 5 TurboChannel (ASIC) + * 6 Halt Keycode from Access.Bus keyboard (CTRL-ALT-ENTER) + * 7 FPU/R4k timer + * + * DS5000/2xx's, aka kn03, aka 3maxplus: + * + * MIPS IRQ Source + * -------- ------ + * 0 Software (ignored) + * 1 Software (ignored) + * 2 System Board (ASIC) + * 3 RTC + * 4 Reserved + * 5 Memory + * 6 Halt Button + * 7 FPU/R4k timer + * + * We handle the IRQ according to _our_ priority (see setup.c), + * then we just return. If multiple IRQs are pending then we will + * just take another exception, big deal. + */ + .align 5 + NESTED(plat_irq_dispatch, PT_SIZE, ra) + .set noreorder + + /* + * Get pending Interrupts + */ + mfc0 t0,CP0_CAUSE # get pending interrupts + mfc0 t1,CP0_STATUS +#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) + lw t2,cpu_fpu_mask +#endif + andi t0,ST0_IM # CAUSE.CE may be non-zero! + and t0,t1 # isolate allowed ones + + beqz t0,spurious + +#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) + and t2,t0 + bnez t2,fpu # handle FPU immediately +#endif + + /* + * Find irq with highest priority + */ + # open coded PTR_LA t1, cpu_mask_nr_tbl +#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) + # open coded la t1, cpu_mask_nr_tbl + lui t1, %hi(cpu_mask_nr_tbl) + addiu t1, %lo(cpu_mask_nr_tbl) +#else +#error GCC `-msym32' option required for 64-bit DECstation builds +#endif +1: lw t2,(t1) + nop + and t2,t0 + beqz t2,1b + addu t1,2*PTRSIZE # delay slot + + /* + * Do the low-level stuff + */ + lw a0,(-PTRSIZE)(t1) + nop + bgez a0,handle_it # irq_nr >= 0? + # irq_nr < 0: it is an address + nop + jr a0 + # a trick to save a branch: + lui t2,(KN03_IOASIC_BASE>>16)&0xffff + # upper part of IOASIC Address + +/* + * Handle "IRQ Controller" Interrupts + * Masked Interrupts are still visible and have to be masked "by hand". + */ + FEXPORT(kn02_io_int) # 3max + lui t0,(KN02_CSR_BASE>>16)&0xffff + # get interrupt status and mask + lw t0,(t0) + nop + andi t1,t0,KN02_IRQ_ALL + b 1f + srl t0,16 # shift interrupt mask + + FEXPORT(kn02xa_io_int) # 3min/maxine + lui t2,(KN02XA_IOASIC_BASE>>16)&0xffff + # upper part of IOASIC Address + + FEXPORT(kn03_io_int) # 3max+ (t2 loaded earlier) + lw t0,IO_REG_SIR(t2) # get status: IOASIC sir + lw t1,IO_REG_SIMR(t2) # get mask: IOASIC simr + nop + +1: and t0,t1 # mask out allowed ones + + beqz t0,spurious + + /* + * Find irq with highest priority + */ + # open coded PTR_LA t1,asic_mask_nr_tbl +#if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) + # open coded la t1, asic_mask_nr_tbl + lui t1, %hi(asic_mask_nr_tbl) + addiu t1, %lo(asic_mask_nr_tbl) +#else +#error GCC `-msym32' option required for 64-bit DECstation builds +#endif +2: lw t2,(t1) + nop + and t2,t0 + beq zero,t2,2b + addu t1,2*PTRSIZE # delay slot + + /* + * Do the low-level stuff + */ + lw a0,%lo(-PTRSIZE)(t1) + nop + bgez a0,handle_it # irq_nr >= 0? + # irq_nr < 0: it is an address + nop + jr a0 + nop # delay slot + +/* + * Dispatch low-priority interrupts. We reconsider all status + * bits again, which looks like a lose, but it makes the code + * simple and O(log n), so it gets compensated. + */ + FEXPORT(cpu_all_int) # HALT, timers, software junk + li a0,DEC_CPU_IRQ_BASE + srl t0,CAUSEB_IP + li t1,CAUSEF_IP>>CAUSEB_IP # mask + b 1f + li t2,4 # nr of bits / 2 + + FEXPORT(kn02_all_int) # impossible ? + li a0,KN02_IRQ_BASE + li t1,KN02_IRQ_ALL # mask + b 1f + li t2,4 # nr of bits / 2 + + FEXPORT(asic_all_int) # various I/O ASIC junk + li a0,IO_IRQ_BASE + li t1,IO_IRQ_ALL # mask + b 1f + li t2,8 # nr of bits / 2 + +/* + * Dispatch DMA interrupts -- O(log n). + */ + FEXPORT(asic_dma_int) # I/O ASIC DMA events + li a0,IO_IRQ_BASE+IO_INR_DMA + srl t0,IO_INR_DMA + li t1,IO_IRQ_DMA>>IO_INR_DMA # mask + li t2,8 # nr of bits / 2 + + /* + * Find irq with highest priority. + * Highest irq number takes precedence. + */ +1: srlv t3,t1,t2 +2: xor t1,t3 + and t3,t0,t1 + beqz t3,3f + nop + move t0,t3 + addu a0,t2 +3: srl t2,1 + bnez t2,2b + srlv t3,t1,t2 + +handle_it: + j dec_irq_dispatch + nop + +#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) +fpu: + lw t0,fpu_kstat_irq + nop + lw t1,(t0) + nop + addu t1,1 + j handle_fpe_int + sw t1,(t0) +#endif + +spurious: + j spurious_interrupt + nop + END(plat_irq_dispatch) + +/* + * Generic unimplemented interrupt routines -- cpu_mask_nr_tbl + * and asic_mask_nr_tbl are initialized to point all interrupts here. + * The tables are then filled in by machine-specific initialisation + * in dec_setup(). + */ + FEXPORT(dec_intr_unimplemented) + move a1,t0 # cheats way of printing an arg! + ASM_PANIC("Unimplemented cpu interrupt! CP0_CAUSE: 0x%08x"); + + FEXPORT(asic_intr_unimplemented) + move a1,t0 # cheats way of printing an arg! + ASM_PANIC("Unimplemented asic interrupt! ASIC ISR: 0x%08x"); |