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/*
* arch/mips/dec/int-handler.S
*
* Copyright (C) 1995, 1996, 1997 Paul M. Antoine and Harald Koerfgen
*
* Written by Ralf Baechle and Andreas Busse, modified for DECStation
* support by Paul Antoine and Harald Koerfgen.
*
* completly rewritten:
* Copyright (C) 1998 Harald Koerfgen
*
*/
#include <asm/asm.h>
#include <asm/regdef.h>
#include <asm/mipsregs.h>
#include <asm/stackframe.h>
#include <asm/addrspace.h>
#include <asm/dec/interrupts.h>
.text
.set noreorder
/*
* decstation_handle_int: Interrupt handler for DECStations
*
* FIXME: Detection of spurious interrupts not yet implemented!
*
* 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
* 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
*
* 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
*
* 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
*
* We handle the IRQ according to _our_ priority.
* Priority is:
*
* Highest ---- RTC
* SCSI (if separate from TC)
* Ethernet (if separate from TC)
* Serial (if separate from TC)
* TurboChannel (if there is one!)
* Memory Controller (execept kmin)
* Lowest ---- Halt (if there is one!)
*
* then we just return, if multiple IRQs are pending then we will just take
* another exception, big deal.
*
*/
.align 5
NESTED(decstation_handle_int, PT_SIZE, ra)
.set noat
SAVE_ALL
CLI # TEST: interrupts should be off
.set at
.set noreorder
/*
* Get pending Interrupts
*/
mfc0 t0,CP0_CAUSE # get pending interrupts
mfc0 t2,CP0_STATUS
la t1,cpu_mask_tbl
and t0,t2 # isolate allowed ones
/* insert detection of spurious interrupts here */
/*
* Find irq with highest priority
*/
1: lw t2,(t1)
move t3,t0
and t3,t2
beq t3,zero,1b
addu t1,PTRSIZE # delay slot
/*
* Do the low-level stuff
*/
lw a0,%lo(cpu_irq_nr-cpu_mask_tbl-PTRSIZE)(t1)
lw t0,%lo(cpu_ivec_tbl-cpu_mask_tbl-PTRSIZE)(t1)
bgez a0, handle_it # irq_nr >= 0?
# irq_nr < 0: a0 contains an address
nop
jr t0
nop # delay slot
/*
* Handle "IRQ Controller" Interrupts
* Masked Interrupts are still visible and have to be masked "by hand".
* %hi(KN02_CSR_ADDR) does not work so all addresses are hardcoded :-(.
*/
EXPORT(kn02_io_int)
kn02_io_int: lui t0,0xbff0 # get interrupt status and mask
lw t0,(t0)
la t1,asic_mask_tbl
move t3,t0
sll t3,16 # shift interrupt status
b find_int
and t0,t3 # mask out allowed ones
EXPORT(kn03_io_int)
kn03_io_int: lui t2,0xbf84 # upper part of IOASIC Address
lw t0,0x0110(t2) # get status: IOASIC isr
lw t3,0x0120(t2) # get mask: IOASIC isrm
la t1,asic_mask_tbl
b find_int
and t0,t3 # mask out allowed ones
EXPORT(kn02ba_io_int)
kn02ba_io_int: lui t2,0xbc04
lw t0,0x0110(t2) # IOASIC isr, works for maxine also
lw t3,0x0120(t2) # IOASIC isrm
la t1,asic_mask_tbl
and t0,t3
/*
* Find irq with highest priority
*/
find_int: lw t2,(t1)
move t3,t0
and t3,t2
beq zero,t3,find_int
addu t1,PTRSIZE # delay slot
/*
* Do the low-level stuff
*/
lw a0,%lo(asic_irq_nr-asic_mask_tbl-PTRSIZE)(t1)
nop
handle_it: jal do_IRQ
move a1,sp
j ret_from_irq
nop
END(decstation_handle_int)
/*
* Interrupt routines common to all DECStations first.
*/
EXPORT(dec_intr_fpu)
dec_intr_fpu: PANIC("Unimplemented FPU interrupt handler")
/*
* Halt interrupt
*/
EXPORT(intr_halt)
intr_halt: la k0,0xbc000000
jr k0
nop
/*
* Generic unimplemented interrupt routines - ivec_tbl is initialised to
* point all interrupts here. The table is then filled in by machine-specific
* initialisation in dec_setup().
*/
EXPORT(dec_intr_unimplemented)
dec_intr_unimplemented:
mfc0 a1,CP0_CAUSE # cheats way of printing an arg!
nop # to be sure...
PANIC("Unimplemented cpu interrupt! CP0_CAUSE: 0x%x");
EXPORT(asic_intr_unimplemented)
asic_intr_unimplemented:
move a1,t0 # cheats way of printing an arg!
PANIC("Unimplemented asic interrupt! ASIC ISR: 0x%x");
/*
* FIXME: This interrupt vector table is experimental. It is initialised with
* *_intr_unimplemented and filled in with the addresses of
* machine-specific interrupt routines in dec_setup() Paul 10/5/97.
*
* The mask_tbls contain the interrupt masks which are used. It is
* initialised with all possible interrupt status bits set, so that
* unused Interrupts are catched. Harald
*/
.data
EXPORT(cpu_mask_tbl)
cpu_mask_tbl:
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000 # these two are unlikely
.word 0x00000000 # to be used
.word 0x0000ff00 # End of list
EXPORT(cpu_irq_nr)
cpu_irq_nr:
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000
.word 0x00000000 # these two are unlikely
.word 0x00000000 # to be used
.word 0x00ffffff # End of list
EXPORT(cpu_ivec_tbl)
cpu_ivec_tbl:
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented
PTR dec_intr_unimplemented # these two are unlikely
PTR dec_intr_unimplemented # to be used
PTR dec_intr_unimplemented # EOL
EXPORT(asic_mask_tbl)
asic_mask_tbl:
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0xffffffff # EOL
EXPORT(asic_irq_nr)
asic_irq_nr:
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0
.word 0xffffffff # EOL
|
