1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (C) 1995, 1996, 1997 Paul M. Antoine and Harald Koerfgen 4 * Copyright (C) 2000, 2001, 2002, 2003, 2005 Maciej W. Rozycki 5 * 6 * Written by Ralf Baechle and Andreas Busse, modified for DECstation 7 * support by Paul Antoine and Harald Koerfgen. 8 * 9 * completely rewritten: 10 * Copyright (C) 1998 Harald Koerfgen 11 * 12 * Rewritten extensively for controller-driven IRQ support 13 * by Maciej W. Rozycki. 14 */ 15 16 #include <asm/addrspace.h> 17 #include <asm/asm.h> 18 #include <asm/mipsregs.h> 19 #include <asm/regdef.h> 20 #include <asm/stackframe.h> 21 22 #include <asm/dec/interrupts.h> 23 #include <asm/dec/ioasic_addrs.h> 24 #include <asm/dec/ioasic_ints.h> 25 #include <asm/dec/kn01.h> 26 #include <asm/dec/kn02.h> 27 #include <asm/dec/kn02xa.h> 28 #include <asm/dec/kn03.h> 29 30 #define KN02_CSR_BASE CKSEG1ADDR(KN02_SLOT_BASE + KN02_CSR) 31 #define KN02XA_IOASIC_BASE CKSEG1ADDR(KN02XA_SLOT_BASE + IOASIC_IOCTL) 32 #define KN03_IOASIC_BASE CKSEG1ADDR(KN03_SLOT_BASE + IOASIC_IOCTL) 33 34 .text 35 .set noreorder 36 /* 37 * plat_irq_dispatch: Interrupt handler for DECstations 38 * 39 * We follow the model in the Indy interrupt code by David Miller, where he 40 * says: a lot of complication here is taken away because: 41 * 42 * 1) We handle one interrupt and return, sitting in a loop 43 * and moving across all the pending IRQ bits in the cause 44 * register is _NOT_ the answer, the common case is one 45 * pending IRQ so optimize in that direction. 46 * 47 * 2) We need not check against bits in the status register 48 * IRQ mask, that would make this routine slow as hell. 49 * 50 * 3) Linux only thinks in terms of all IRQs on or all IRQs 51 * off, nothing in between like BSD spl() brain-damage. 52 * 53 * Furthermore, the IRQs on the DECstations look basically (barring 54 * software IRQs which we don't use at all) like... 55 * 56 * DS2100/3100's, aka kn01, aka Pmax: 57 * 58 * MIPS IRQ Source 59 * -------- ------ 60 * 0 Software (ignored) 61 * 1 Software (ignored) 62 * 2 SCSI 63 * 3 Lance Ethernet 64 * 4 DZ11 serial 65 * 5 RTC 66 * 6 Memory Controller & Video 67 * 7 FPU 68 * 69 * DS5000/200, aka kn02, aka 3max: 70 * 71 * MIPS IRQ Source 72 * -------- ------ 73 * 0 Software (ignored) 74 * 1 Software (ignored) 75 * 2 TurboChannel 76 * 3 RTC 77 * 4 Reserved 78 * 5 Memory Controller 79 * 6 Reserved 80 * 7 FPU 81 * 82 * DS5000/1xx's, aka kn02ba, aka 3min: 83 * 84 * MIPS IRQ Source 85 * -------- ------ 86 * 0 Software (ignored) 87 * 1 Software (ignored) 88 * 2 TurboChannel Slot 0 89 * 3 TurboChannel Slot 1 90 * 4 TurboChannel Slot 2 91 * 5 TurboChannel Slot 3 (ASIC) 92 * 6 Halt button 93 * 7 FPU/R4k timer 94 * 95 * DS5000/2x's, aka kn02ca, aka maxine: 96 * 97 * MIPS IRQ Source 98 * -------- ------ 99 * 0 Software (ignored) 100 * 1 Software (ignored) 101 * 2 Periodic Interrupt (100usec) 102 * 3 RTC 103 * 4 I/O write timeout 104 * 5 TurboChannel (ASIC) 105 * 6 Halt Keycode from Access.Bus keyboard (CTRL-ALT-ENTER) 106 * 7 FPU/R4k timer 107 * 108 * DS5000/2xx's, aka kn03, aka 3maxplus: 109 * 110 * MIPS IRQ Source 111 * -------- ------ 112 * 0 Software (ignored) 113 * 1 Software (ignored) 114 * 2 System Board (ASIC) 115 * 3 RTC 116 * 4 Reserved 117 * 5 Memory 118 * 6 Halt Button 119 * 7 FPU/R4k timer 120 * 121 * We handle the IRQ according to _our_ priority (see setup.c), 122 * then we just return. If multiple IRQs are pending then we will 123 * just take another exception, big deal. 124 */ 125 .align 5 126 NESTED(plat_irq_dispatch, PT_SIZE, ra) 127 .set noreorder 128 129 /* 130 * Get pending Interrupts 131 */ 132 mfc0 t0,CP0_CAUSE # get pending interrupts 133 mfc0 t1,CP0_STATUS 134 #if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) 135 lw t2,cpu_fpu_mask 136 #endif 137 andi t0,ST0_IM # CAUSE.CE may be non-zero! 138 and t0,t1 # isolate allowed ones 139 140 beqz t0,spurious 141 142 #if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) 143 and t2,t0 144 bnez t2,fpu # handle FPU immediately 145 #endif 146 147 /* 148 * Find irq with highest priority 149 */ 150 # open coded PTR_LA t1, cpu_mask_nr_tbl 151 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) 152 # open coded la t1, cpu_mask_nr_tbl 153 lui t1, %hi(cpu_mask_nr_tbl) 154 addiu t1, %lo(cpu_mask_nr_tbl) 155 #else 156 #error GCC `-msym32' option required for 64-bit DECstation builds 157 #endif 158 1: lw t2,(t1) 159 nop 160 and t2,t0 161 beqz t2,1b 162 addu t1,2*PTRSIZE # delay slot 163 164 /* 165 * Do the low-level stuff 166 */ 167 lw a0,(-PTRSIZE)(t1) 168 nop 169 bgez a0,handle_it # irq_nr >= 0? 170 # irq_nr < 0: it is an address 171 nop 172 jr a0 173 # a trick to save a branch: 174 lui t2,(KN03_IOASIC_BASE>>16)&0xffff 175 # upper part of IOASIC Address 176 177 /* 178 * Handle "IRQ Controller" Interrupts 179 * Masked Interrupts are still visible and have to be masked "by hand". 180 */ 181 FEXPORT(kn02_io_int) # 3max 182 lui t0,(KN02_CSR_BASE>>16)&0xffff 183 # get interrupt status and mask 184 lw t0,(t0) 185 nop 186 andi t1,t0,KN02_IRQ_ALL 187 b 1f 188 srl t0,16 # shift interrupt mask 189 190 FEXPORT(kn02xa_io_int) # 3min/maxine 191 lui t2,(KN02XA_IOASIC_BASE>>16)&0xffff 192 # upper part of IOASIC Address 193 194 FEXPORT(kn03_io_int) # 3max+ (t2 loaded earlier) 195 lw t0,IO_REG_SIR(t2) # get status: IOASIC sir 196 lw t1,IO_REG_SIMR(t2) # get mask: IOASIC simr 197 nop 198 199 1: and t0,t1 # mask out allowed ones 200 201 beqz t0,spurious 202 203 /* 204 * Find irq with highest priority 205 */ 206 # open coded PTR_LA t1,asic_mask_nr_tbl 207 #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) 208 # open coded la t1, asic_mask_nr_tbl 209 lui t1, %hi(asic_mask_nr_tbl) 210 addiu t1, %lo(asic_mask_nr_tbl) 211 #else 212 #error GCC `-msym32' option required for 64-bit DECstation builds 213 #endif 214 2: lw t2,(t1) 215 nop 216 and t2,t0 217 beq zero,t2,2b 218 addu t1,2*PTRSIZE # delay slot 219 220 /* 221 * Do the low-level stuff 222 */ 223 lw a0,%lo(-PTRSIZE)(t1) 224 nop 225 bgez a0,handle_it # irq_nr >= 0? 226 # irq_nr < 0: it is an address 227 nop 228 jr a0 229 nop # delay slot 230 231 /* 232 * Dispatch low-priority interrupts. We reconsider all status 233 * bits again, which looks like a lose, but it makes the code 234 * simple and O(log n), so it gets compensated. 235 */ 236 FEXPORT(cpu_all_int) # HALT, timers, software junk 237 li a0,DEC_CPU_IRQ_BASE 238 srl t0,CAUSEB_IP 239 li t1,CAUSEF_IP>>CAUSEB_IP # mask 240 b 1f 241 li t2,4 # nr of bits / 2 242 243 FEXPORT(kn02_all_int) # impossible ? 244 li a0,KN02_IRQ_BASE 245 li t1,KN02_IRQ_ALL # mask 246 b 1f 247 li t2,4 # nr of bits / 2 248 249 FEXPORT(asic_all_int) # various I/O ASIC junk 250 li a0,IO_IRQ_BASE 251 li t1,IO_IRQ_ALL # mask 252 b 1f 253 li t2,8 # nr of bits / 2 254 255 /* 256 * Dispatch DMA interrupts -- O(log n). 257 */ 258 FEXPORT(asic_dma_int) # I/O ASIC DMA events 259 li a0,IO_IRQ_BASE+IO_INR_DMA 260 srl t0,IO_INR_DMA 261 li t1,IO_IRQ_DMA>>IO_INR_DMA # mask 262 li t2,8 # nr of bits / 2 263 264 /* 265 * Find irq with highest priority. 266 * Highest irq number takes precedence. 267 */ 268 1: srlv t3,t1,t2 269 2: xor t1,t3 270 and t3,t0,t1 271 beqz t3,3f 272 nop 273 move t0,t3 274 addu a0,t2 275 3: srl t2,1 276 bnez t2,2b 277 srlv t3,t1,t2 278 279 handle_it: 280 j dec_irq_dispatch 281 nop 282 283 #if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT) 284 fpu: 285 lw t0,fpu_kstat_irq 286 nop 287 lw t1,(t0) 288 nop 289 addu t1,1 290 j handle_fpe_int 291 sw t1,(t0) 292 #endif 293 294 spurious: 295 j spurious_interrupt 296 nop 297 END(plat_irq_dispatch) 298 299 /* 300 * Generic unimplemented interrupt routines -- cpu_mask_nr_tbl 301 * and asic_mask_nr_tbl are initialized to point all interrupts here. 302 * The tables are then filled in by machine-specific initialisation 303 * in dec_setup(). 304 */ 305 FEXPORT(dec_intr_unimplemented) 306 move a1,t0 # cheats way of printing an arg! 307 ASM_PANIC("Unimplemented cpu interrupt! CP0_CAUSE: 0x%08x"); 308 309 FEXPORT(asic_intr_unimplemented) 310 move a1,t0 # cheats way of printing an arg! 311 ASM_PANIC("Unimplemented asic interrupt! ASIC ISR: 0x%08x"); 312