arch/mips/dec/int-handler.S

   1 /*
   2  * Copyright (C) 1995, 1996, 1997 Paul M. Antoine and Harald Koerfgen
   3  * Copyright (C) 2000, 2001, 2002, 2003, 2005  Maciej W. Rozycki
   4  *
   5  * Written by Ralf Baechle and Andreas Busse, modified for DECstation
   6  * support by Paul Antoine and Harald Koerfgen.
   7  *
   8  * completely rewritten:
   9  * Copyright (C) 1998 Harald Koerfgen
  10  *
  11  * Rewritten extensively for controller-driven IRQ support
  12  * by Maciej W. Rozycki.
  13  */
  14
  15 #include <asm/addrspace.h>
  16 #include <asm/asm.h>
  17 #include <asm/mipsregs.h>
  18 #include <asm/regdef.h>
  19 #include <asm/stackframe.h>
  20
  21 #include <asm/dec/interrupts.h>
  22 #include <asm/dec/ioasic_addrs.h>
  23 #include <asm/dec/ioasic_ints.h>
  24 #include <asm/dec/kn01.h>
  25 #include <asm/dec/kn02.h>
  26 #include <asm/dec/kn02xa.h>
  27 #include <asm/dec/kn03.h>
  28
  29 #define KN02_CSR_BASE           CKSEG1ADDR(KN02_SLOT_BASE + KN02_CSR)
  30 #define KN02XA_IOASIC_BASE      CKSEG1ADDR(KN02XA_SLOT_BASE + IOASIC_IOCTL)
  31 #define KN03_IOASIC_BASE        CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_IOCTL)
  32
  33                 .text
  34                 .set    noreorder
  35 /*
  36  * plat_irq_dispatch: Interrupt handler for DECstations
  37  *
  38  * We follow the model in the Indy interrupt code by David Miller, where he
  39  * says: a lot of complication here is taken away because:
  40  *
  41  * 1) We handle one interrupt and return, sitting in a loop
  42  *    and moving across all the pending IRQ bits in the cause
  43  *    register is _NOT_ the answer, the common case is one
  44  *    pending IRQ so optimize in that direction.
  45  *
  46  * 2) We need not check against bits in the status register
  47  *    IRQ mask, that would make this routine slow as hell.
  48  *
  49  * 3) Linux only thinks in terms of all IRQs on or all IRQs
  50  *    off, nothing in between like BSD spl() brain-damage.
  51  *
  52  * Furthermore, the IRQs on the DECstations look basically (barring
  53  * software IRQs which we don't use at all) like...
  54  *
  55  * DS2100/3100's, aka kn01, aka Pmax:
  56  *
  57  *      MIPS IRQ        Source
  58  *      --------        ------
  59  *             0        Software (ignored)
  60  *             1        Software (ignored)
  61  *             2        SCSI
  62  *             3        Lance Ethernet
  63  *             4        DZ11 serial
  64  *             5        RTC
  65  *             6        Memory Controller & Video
  66  *             7        FPU
  67  *
  68  * DS5000/200, aka kn02, aka 3max:
  69  *
  70  *      MIPS IRQ        Source
  71  *      --------        ------
  72  *             0        Software (ignored)
  73  *             1        Software (ignored)
  74  *             2        TurboChannel
  75  *             3        RTC
  76  *             4        Reserved
  77  *             5        Memory Controller
  78  *             6        Reserved
  79  *             7        FPU
  80  *
  81  * DS5000/1xx's, aka kn02ba, aka 3min:
  82  *
  83  *      MIPS IRQ        Source
  84  *      --------        ------
  85  *             0        Software (ignored)
  86  *             1        Software (ignored)
  87  *             2        TurboChannel Slot 0
  88  *             3        TurboChannel Slot 1
  89  *             4        TurboChannel Slot 2
  90  *             5        TurboChannel Slot 3 (ASIC)
  91  *             6        Halt button
  92  *             7        FPU/R4k timer
  93  *
  94  * DS5000/2x's, aka kn02ca, aka maxine:
  95  *
  96  *      MIPS IRQ        Source
  97  *      --------        ------
  98  *             0        Software (ignored)
  99  *             1        Software (ignored)
 100  *             2        Periodic Interrupt (100usec)
 101  *             3        RTC
 102  *             4        I/O write timeout
 103  *             5        TurboChannel (ASIC)
 104  *             6        Halt Keycode from Access.Bus keyboard (CTRL-ALT-ENTER)
 105  *             7        FPU/R4k timer
 106  *
 107  * DS5000/2xx's, aka kn03, aka 3maxplus:
 108  *
 109  *      MIPS IRQ        Source
 110  *      --------        ------
 111  *             0        Software (ignored)
 112  *             1        Software (ignored)
 113  *             2        System Board (ASIC)
 114  *             3        RTC
 115  *             4        Reserved
 116  *             5        Memory
 117  *             6        Halt Button
 118  *             7        FPU/R4k timer
 119  *
 120  * We handle the IRQ according to _our_ priority (see setup.c),
 121  * then we just return.  If multiple IRQs are pending then we will
 122  * just take another exception, big deal.
 123  */
 124                 .align  5
 125                 NESTED(plat_irq_dispatch, PT_SIZE, ra)
 126                 .set    noreorder
 127
 128                 /*
 129                  * Get pending Interrupts
 130                  */
 131                 mfc0    t0,CP0_CAUSE            # get pending interrupts
 132                 mfc0    t1,CP0_STATUS
 133 #ifdef CONFIG_32BIT
 134                 lw      t2,cpu_fpu_mask
 135 #endif
 136                 andi    t0,ST0_IM               # CAUSE.CE may be non-zero!
 137                 and     t0,t1                   # isolate allowed ones
 138
 139                 beqz    t0,spurious
 140
 141 #ifdef CONFIG_32BIT
 142                  and    t2,t0
 143                 bnez    t2,fpu                  # handle FPU immediately
 144 #endif
 145
 146                 /*
 147                  * Find irq with highest priority
 148                  */
 149                  PTR_LA t1,cpu_mask_nr_tbl
 150 1:              lw      t2,(t1)
 151                 nop
 152                 and     t2,t0
 153                 beqz    t2,1b
 154                  addu   t1,2*PTRSIZE            # delay slot
 155
 156                 /*
 157                  * Do the low-level stuff
 158                  */
 159                 lw      a0,(-PTRSIZE)(t1)
 160                 nop
 161                 bgez    a0,handle_it            # irq_nr >= 0?
 162                                                 # irq_nr < 0: it is an address
 163                  nop
 164                 jr      a0
 165                                                 # a trick to save a branch:
 166                  lui    t2,(KN03_IOASIC_BASE>>16)&0xffff
 167                                                 # upper part of IOASIC Address
 168
 169 /*
 170  * Handle "IRQ Controller" Interrupts
 171  * Masked Interrupts are still visible and have to be masked "by hand".
 172  */
 173                 FEXPORT(kn02_io_int)            # 3max
 174                 lui     t0,(KN02_CSR_BASE>>16)&0xffff
 175                                                 # get interrupt status and mask
 176                 lw      t0,(t0)
 177                 nop
 178                 andi    t1,t0,KN02_IRQ_ALL
 179                 b       1f
 180                  srl    t0,16                   # shift interrupt mask
 181
 182                 FEXPORT(kn02xa_io_int)          # 3min/maxine
 183                 lui     t2,(KN02XA_IOASIC_BASE>>16)&0xffff
 184                                                 # upper part of IOASIC Address
 185
 186                 FEXPORT(kn03_io_int)            # 3max+ (t2 loaded earlier)
 187                 lw      t0,IO_REG_SIR(t2)       # get status: IOASIC sir
 188                 lw      t1,IO_REG_SIMR(t2)      # get mask:   IOASIC simr
 189                 nop
 190
 191 1:              and     t0,t1                   # mask out allowed ones
 192
 193                 beqz    t0,spurious
 194
 195                 /*
 196                  * Find irq with highest priority
 197                  */
 198                  PTR_LA t1,asic_mask_nr_tbl
 199 2:              lw      t2,(t1)
 200                 nop
 201                 and     t2,t0
 202                 beq     zero,t2,2b
 203                  addu   t1,2*PTRSIZE            # delay slot
 204
 205                 /*
 206                  * Do the low-level stuff
 207                  */
 208                 lw      a0,%lo(-PTRSIZE)(t1)
 209                 nop
 210                 bgez    a0,handle_it            # irq_nr >= 0?
 211                                                 # irq_nr < 0: it is an address
 212                  nop
 213                 jr      a0
 214                  nop                            # delay slot
 215
 216 /*
 217  * Dispatch low-priority interrupts.  We reconsider all status
 218  * bits again, which looks like a lose, but it makes the code
 219  * simple and O(log n), so it gets compensated.
 220  */
 221                 FEXPORT(cpu_all_int)            # HALT, timers, software junk
 222                 li      a0,DEC_CPU_IRQ_BASE
 223                 srl     t0,CAUSEB_IP
 224                 li      t1,CAUSEF_IP>>CAUSEB_IP # mask
 225                 b       1f
 226                  li     t2,4                    # nr of bits / 2
 227
 228                 FEXPORT(kn02_all_int)           # impossible ?
 229                 li      a0,KN02_IRQ_BASE
 230                 li      t1,KN02_IRQ_ALL         # mask
 231                 b       1f
 232                  li     t2,4                    # nr of bits / 2
 233
 234                 FEXPORT(asic_all_int)           # various I/O ASIC junk
 235                 li      a0,IO_IRQ_BASE
 236                 li      t1,IO_IRQ_ALL           # mask
 237                 b       1f
 238                  li     t2,8                    # nr of bits / 2
 239
 240 /*
 241  * Dispatch DMA interrupts -- O(log n).
 242  */
 243                 FEXPORT(asic_dma_int)           # I/O ASIC DMA events
 244                 li      a0,IO_IRQ_BASE+IO_INR_DMA
 245                 srl     t0,IO_INR_DMA
 246                 li      t1,IO_IRQ_DMA>>IO_INR_DMA # mask
 247                 li      t2,8                    # nr of bits / 2
 248
 249                 /*
 250                  * Find irq with highest priority.
 251                  * Highest irq number takes precedence.
 252                  */
 253 1:              srlv    t3,t1,t2
 254 2:              xor     t1,t3
 255                 and     t3,t0,t1
 256                 beqz    t3,3f
 257                  nop
 258                 move    t0,t3
 259                 addu    a0,t2
 260 3:              srl     t2,1
 261                 bnez    t2,2b
 262                  srlv   t3,t1,t2
 263
 264 handle_it:
 265                 j       dec_irq_dispatch
 266                  nop
 267
 268 #ifdef CONFIG_32BIT
 269 fpu:
 270                 lw      t0,fpu_kstat_irq
 271                 nop
 272                 lw      t1,(t0)
 273                 nop
 274                 addu    t1,1
 275                 j       handle_fpe_int
 276                  sw     t1,(t0)
 277 #endif
 278
 279 spurious:
 280                 j       spurious_interrupt
 281                  nop
 282                 END(plat_irq_dispatch)
 283
 284 /*
 285  * Generic unimplemented interrupt routines -- cpu_mask_nr_tbl
 286  * and asic_mask_nr_tbl are initialized to point all interrupts here.
 287  * The tables are then filled in by machine-specific initialisation
 288  * in dec_setup().
 289  */
 290                 FEXPORT(dec_intr_unimplemented)
 291                 move    a1,t0                   # cheats way of printing an arg!
 292                 PANIC("Unimplemented cpu interrupt! CP0_CAUSE: 0x%08x");
 293
 294                 FEXPORT(asic_intr_unimplemented)
 295                 move    a1,t0                   # cheats way of printing an arg!
 296                 PANIC("Unimplemented asic interrupt! ASIC ISR: 0x%08x");