1 /* 2 * ARM CMSDK APB watchdog emulation 3 * 4 * Copyright (c) 2018 Linaro Limited 5 * Written by Peter Maydell 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 or 9 * (at your option) any later version. 10 */ 11 12 /* 13 * This is a model of the "APB watchdog" which is part of the Cortex-M 14 * System Design Kit (CMSDK) and documented in the Cortex-M System 15 * Design Kit Technical Reference Manual (ARM DDI0479C): 16 * https://developer.arm.com/products/system-design/system-design-kits/cortex-m-system-design-kit 17 * 18 * We also support the variant of this device found in the TI 19 * Stellaris/Luminary boards and documented in: 20 * http://www.ti.com/lit/ds/symlink/lm3s6965.pdf 21 */ 22 23 #include "qemu/osdep.h" 24 #include "qemu/log.h" 25 #include "trace.h" 26 #include "qapi/error.h" 27 #include "qemu/module.h" 28 #include "sysemu/watchdog.h" 29 #include "hw/sysbus.h" 30 #include "hw/irq.h" 31 #include "hw/qdev-properties.h" 32 #include "hw/registerfields.h" 33 #include "hw/watchdog/cmsdk-apb-watchdog.h" 34 #include "migration/vmstate.h" 35 36 REG32(WDOGLOAD, 0x0) 37 REG32(WDOGVALUE, 0x4) 38 REG32(WDOGCONTROL, 0x8) 39 FIELD(WDOGCONTROL, INTEN, 0, 1) 40 FIELD(WDOGCONTROL, RESEN, 1, 1) 41 #define R_WDOGCONTROL_VALID_MASK (R_WDOGCONTROL_INTEN_MASK | \ 42 R_WDOGCONTROL_RESEN_MASK) 43 REG32(WDOGINTCLR, 0xc) 44 REG32(WDOGRIS, 0x10) 45 FIELD(WDOGRIS, INT, 0, 1) 46 REG32(WDOGMIS, 0x14) 47 REG32(WDOGTEST, 0x418) /* only in Stellaris/Luminary version of the device */ 48 REG32(WDOGLOCK, 0xc00) 49 #define WDOG_UNLOCK_VALUE 0x1ACCE551 50 REG32(WDOGITCR, 0xf00) 51 FIELD(WDOGITCR, ENABLE, 0, 1) 52 #define R_WDOGITCR_VALID_MASK R_WDOGITCR_ENABLE_MASK 53 REG32(WDOGITOP, 0xf04) 54 FIELD(WDOGITOP, WDOGRES, 0, 1) 55 FIELD(WDOGITOP, WDOGINT, 1, 1) 56 #define R_WDOGITOP_VALID_MASK (R_WDOGITOP_WDOGRES_MASK | \ 57 R_WDOGITOP_WDOGINT_MASK) 58 REG32(PID4, 0xfd0) 59 REG32(PID5, 0xfd4) 60 REG32(PID6, 0xfd8) 61 REG32(PID7, 0xfdc) 62 REG32(PID0, 0xfe0) 63 REG32(PID1, 0xfe4) 64 REG32(PID2, 0xfe8) 65 REG32(PID3, 0xfec) 66 REG32(CID0, 0xff0) 67 REG32(CID1, 0xff4) 68 REG32(CID2, 0xff8) 69 REG32(CID3, 0xffc) 70 71 /* PID/CID values */ 72 static const uint32_t cmsdk_apb_watchdog_id[] = { 73 0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */ 74 0x24, 0xb8, 0x1b, 0x00, /* PID0..PID3 */ 75 0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */ 76 }; 77 78 static const uint32_t luminary_watchdog_id[] = { 79 0x00, 0x00, 0x00, 0x00, /* PID4..PID7 */ 80 0x05, 0x18, 0x18, 0x01, /* PID0..PID3 */ 81 0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */ 82 }; 83 84 static bool cmsdk_apb_watchdog_intstatus(CMSDKAPBWatchdog *s) 85 { 86 /* Return masked interrupt status */ 87 return s->intstatus && (s->control & R_WDOGCONTROL_INTEN_MASK); 88 } 89 90 static bool cmsdk_apb_watchdog_resetstatus(CMSDKAPBWatchdog *s) 91 { 92 /* Return masked reset status */ 93 return s->resetstatus && (s->control & R_WDOGCONTROL_RESEN_MASK); 94 } 95 96 static void cmsdk_apb_watchdog_update(CMSDKAPBWatchdog *s) 97 { 98 bool wdogint; 99 bool wdogres; 100 101 if (s->itcr) { 102 /* 103 * Not checking that !s->is_luminary since s->itcr can't be written 104 * when s->is_luminary in the first place. 105 */ 106 wdogint = s->itop & R_WDOGITOP_WDOGINT_MASK; 107 wdogres = s->itop & R_WDOGITOP_WDOGRES_MASK; 108 } else { 109 wdogint = cmsdk_apb_watchdog_intstatus(s); 110 wdogres = cmsdk_apb_watchdog_resetstatus(s); 111 } 112 113 qemu_set_irq(s->wdogint, wdogint); 114 if (wdogres) { 115 watchdog_perform_action(); 116 } 117 } 118 119 static uint64_t cmsdk_apb_watchdog_read(void *opaque, hwaddr offset, 120 unsigned size) 121 { 122 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque); 123 uint64_t r; 124 125 switch (offset) { 126 case A_WDOGLOAD: 127 r = ptimer_get_limit(s->timer); 128 break; 129 case A_WDOGVALUE: 130 r = ptimer_get_count(s->timer); 131 break; 132 case A_WDOGCONTROL: 133 r = s->control; 134 break; 135 case A_WDOGRIS: 136 r = s->intstatus; 137 break; 138 case A_WDOGMIS: 139 r = cmsdk_apb_watchdog_intstatus(s); 140 break; 141 case A_WDOGLOCK: 142 r = s->lock; 143 break; 144 case A_WDOGITCR: 145 if (s->is_luminary) { 146 goto bad_offset; 147 } 148 r = s->itcr; 149 break; 150 case A_PID4 ... A_CID3: 151 r = s->id[(offset - A_PID4) / 4]; 152 break; 153 case A_WDOGINTCLR: 154 case A_WDOGITOP: 155 if (s->is_luminary) { 156 goto bad_offset; 157 } 158 qemu_log_mask(LOG_GUEST_ERROR, 159 "CMSDK APB watchdog read: read of WO offset %x\n", 160 (int)offset); 161 r = 0; 162 break; 163 case A_WDOGTEST: 164 if (!s->is_luminary) { 165 goto bad_offset; 166 } 167 qemu_log_mask(LOG_UNIMP, 168 "Luminary watchdog read: stall not implemented\n"); 169 r = 0; 170 break; 171 default: 172 bad_offset: 173 qemu_log_mask(LOG_GUEST_ERROR, 174 "CMSDK APB watchdog read: bad offset %x\n", (int)offset); 175 r = 0; 176 break; 177 } 178 trace_cmsdk_apb_watchdog_read(offset, r, size); 179 return r; 180 } 181 182 static void cmsdk_apb_watchdog_write(void *opaque, hwaddr offset, 183 uint64_t value, unsigned size) 184 { 185 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque); 186 187 trace_cmsdk_apb_watchdog_write(offset, value, size); 188 189 if (s->lock && offset != A_WDOGLOCK) { 190 /* Write access is disabled via WDOGLOCK */ 191 qemu_log_mask(LOG_GUEST_ERROR, 192 "CMSDK APB watchdog write: write to locked watchdog\n"); 193 return; 194 } 195 196 switch (offset) { 197 case A_WDOGLOAD: 198 /* 199 * Reset the load value and the current count, and make sure 200 * we're counting. 201 */ 202 ptimer_transaction_begin(s->timer); 203 ptimer_set_limit(s->timer, value, 1); 204 ptimer_run(s->timer, 0); 205 ptimer_transaction_commit(s->timer); 206 break; 207 case A_WDOGCONTROL: 208 if (s->is_luminary && 0 != (R_WDOGCONTROL_INTEN_MASK & s->control)) { 209 /* 210 * The Luminary version of this device ignores writes to 211 * this register after the guest has enabled interrupts 212 * (so they can only be disabled again via reset). 213 */ 214 break; 215 } 216 s->control = value & R_WDOGCONTROL_VALID_MASK; 217 cmsdk_apb_watchdog_update(s); 218 break; 219 case A_WDOGINTCLR: 220 s->intstatus = 0; 221 ptimer_transaction_begin(s->timer); 222 ptimer_set_count(s->timer, ptimer_get_limit(s->timer)); 223 ptimer_transaction_commit(s->timer); 224 cmsdk_apb_watchdog_update(s); 225 break; 226 case A_WDOGLOCK: 227 s->lock = (value != WDOG_UNLOCK_VALUE); 228 trace_cmsdk_apb_watchdog_lock(s->lock); 229 break; 230 case A_WDOGITCR: 231 if (s->is_luminary) { 232 goto bad_offset; 233 } 234 s->itcr = value & R_WDOGITCR_VALID_MASK; 235 cmsdk_apb_watchdog_update(s); 236 break; 237 case A_WDOGITOP: 238 if (s->is_luminary) { 239 goto bad_offset; 240 } 241 s->itop = value & R_WDOGITOP_VALID_MASK; 242 cmsdk_apb_watchdog_update(s); 243 break; 244 case A_WDOGVALUE: 245 case A_WDOGRIS: 246 case A_WDOGMIS: 247 case A_PID4 ... A_CID3: 248 qemu_log_mask(LOG_GUEST_ERROR, 249 "CMSDK APB watchdog write: write to RO offset 0x%x\n", 250 (int)offset); 251 break; 252 case A_WDOGTEST: 253 if (!s->is_luminary) { 254 goto bad_offset; 255 } 256 qemu_log_mask(LOG_UNIMP, 257 "Luminary watchdog write: stall not implemented\n"); 258 break; 259 default: 260 bad_offset: 261 qemu_log_mask(LOG_GUEST_ERROR, 262 "CMSDK APB watchdog write: bad offset 0x%x\n", 263 (int)offset); 264 break; 265 } 266 } 267 268 static const MemoryRegionOps cmsdk_apb_watchdog_ops = { 269 .read = cmsdk_apb_watchdog_read, 270 .write = cmsdk_apb_watchdog_write, 271 .endianness = DEVICE_LITTLE_ENDIAN, 272 /* byte/halfword accesses are just zero-padded on reads and writes */ 273 .impl.min_access_size = 4, 274 .impl.max_access_size = 4, 275 .valid.min_access_size = 1, 276 .valid.max_access_size = 4, 277 }; 278 279 static void cmsdk_apb_watchdog_tick(void *opaque) 280 { 281 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(opaque); 282 283 if (!s->intstatus) { 284 /* Count expired for the first time: raise interrupt */ 285 s->intstatus = R_WDOGRIS_INT_MASK; 286 } else { 287 /* Count expired for the second time: raise reset and stop clock */ 288 s->resetstatus = 1; 289 ptimer_stop(s->timer); 290 } 291 cmsdk_apb_watchdog_update(s); 292 } 293 294 static void cmsdk_apb_watchdog_reset(DeviceState *dev) 295 { 296 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(dev); 297 298 trace_cmsdk_apb_watchdog_reset(); 299 s->control = 0; 300 s->intstatus = 0; 301 s->lock = 0; 302 s->itcr = 0; 303 s->itop = 0; 304 s->resetstatus = 0; 305 /* Set the limit and the count */ 306 ptimer_transaction_begin(s->timer); 307 ptimer_set_limit(s->timer, 0xffffffff, 1); 308 ptimer_run(s->timer, 0); 309 ptimer_transaction_commit(s->timer); 310 } 311 312 static void cmsdk_apb_watchdog_init(Object *obj) 313 { 314 SysBusDevice *sbd = SYS_BUS_DEVICE(obj); 315 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(obj); 316 317 memory_region_init_io(&s->iomem, obj, &cmsdk_apb_watchdog_ops, 318 s, "cmsdk-apb-watchdog", 0x1000); 319 sysbus_init_mmio(sbd, &s->iomem); 320 sysbus_init_irq(sbd, &s->wdogint); 321 322 s->is_luminary = false; 323 s->id = cmsdk_apb_watchdog_id; 324 } 325 326 static void cmsdk_apb_watchdog_realize(DeviceState *dev, Error **errp) 327 { 328 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(dev); 329 330 if (s->wdogclk_frq == 0) { 331 error_setg(errp, 332 "CMSDK APB watchdog: wdogclk-frq property must be set"); 333 return; 334 } 335 336 s->timer = ptimer_init(cmsdk_apb_watchdog_tick, s, 337 PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD | 338 PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT | 339 PTIMER_POLICY_NO_IMMEDIATE_RELOAD | 340 PTIMER_POLICY_NO_COUNTER_ROUND_DOWN); 341 342 ptimer_transaction_begin(s->timer); 343 ptimer_set_freq(s->timer, s->wdogclk_frq); 344 ptimer_transaction_commit(s->timer); 345 } 346 347 static const VMStateDescription cmsdk_apb_watchdog_vmstate = { 348 .name = "cmsdk-apb-watchdog", 349 .version_id = 1, 350 .minimum_version_id = 1, 351 .fields = (VMStateField[]) { 352 VMSTATE_PTIMER(timer, CMSDKAPBWatchdog), 353 VMSTATE_UINT32(control, CMSDKAPBWatchdog), 354 VMSTATE_UINT32(intstatus, CMSDKAPBWatchdog), 355 VMSTATE_UINT32(lock, CMSDKAPBWatchdog), 356 VMSTATE_UINT32(itcr, CMSDKAPBWatchdog), 357 VMSTATE_UINT32(itop, CMSDKAPBWatchdog), 358 VMSTATE_UINT32(resetstatus, CMSDKAPBWatchdog), 359 VMSTATE_END_OF_LIST() 360 } 361 }; 362 363 static Property cmsdk_apb_watchdog_properties[] = { 364 DEFINE_PROP_UINT32("wdogclk-frq", CMSDKAPBWatchdog, wdogclk_frq, 0), 365 DEFINE_PROP_END_OF_LIST(), 366 }; 367 368 static void cmsdk_apb_watchdog_class_init(ObjectClass *klass, void *data) 369 { 370 DeviceClass *dc = DEVICE_CLASS(klass); 371 372 dc->realize = cmsdk_apb_watchdog_realize; 373 dc->vmsd = &cmsdk_apb_watchdog_vmstate; 374 dc->reset = cmsdk_apb_watchdog_reset; 375 device_class_set_props(dc, cmsdk_apb_watchdog_properties); 376 } 377 378 static const TypeInfo cmsdk_apb_watchdog_info = { 379 .name = TYPE_CMSDK_APB_WATCHDOG, 380 .parent = TYPE_SYS_BUS_DEVICE, 381 .instance_size = sizeof(CMSDKAPBWatchdog), 382 .instance_init = cmsdk_apb_watchdog_init, 383 .class_init = cmsdk_apb_watchdog_class_init, 384 }; 385 386 static void luminary_watchdog_init(Object *obj) 387 { 388 CMSDKAPBWatchdog *s = CMSDK_APB_WATCHDOG(obj); 389 390 s->is_luminary = true; 391 s->id = luminary_watchdog_id; 392 } 393 394 static const TypeInfo luminary_watchdog_info = { 395 .name = TYPE_LUMINARY_WATCHDOG, 396 .parent = TYPE_CMSDK_APB_WATCHDOG, 397 .instance_init = luminary_watchdog_init 398 }; 399 400 static void cmsdk_apb_watchdog_register_types(void) 401 { 402 type_register_static(&cmsdk_apb_watchdog_info); 403 type_register_static(&luminary_watchdog_info); 404 } 405 406 type_init(cmsdk_apb_watchdog_register_types); 407