1 /* 2 * QEMU educational PCI device 3 * 4 * Copyright (c) 2012-2015 Jiri Slaby 5 * 6 * Permission is hereby granted, free of charge, to any person obtaining a 7 * copy of this software and associated documentation files (the "Software"), 8 * to deal in the Software without restriction, including without limitation 9 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 10 * and/or sell copies of the Software, and to permit persons to whom the 11 * Software is furnished to do so, subject to the following conditions: 12 * 13 * The above copyright notice and this permission notice shall be included in 14 * all copies or substantial portions of the Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 22 * DEALINGS IN THE SOFTWARE. 23 */ 24 25 #include "qemu/osdep.h" 26 #include "qemu/units.h" 27 #include "hw/pci/pci.h" 28 #include "hw/hw.h" 29 #include "hw/pci/msi.h" 30 #include "qemu/timer.h" 31 #include "qom/object.h" 32 #include "qemu/main-loop.h" /* iothread mutex */ 33 #include "qemu/module.h" 34 #include "qapi/visitor.h" 35 36 #define TYPE_PCI_EDU_DEVICE "edu" 37 typedef struct EduState EduState; 38 DECLARE_INSTANCE_CHECKER(EduState, EDU, 39 TYPE_PCI_EDU_DEVICE) 40 41 #define FACT_IRQ 0x00000001 42 #define DMA_IRQ 0x00000100 43 44 #define DMA_START 0x40000 45 #define DMA_SIZE 4096 46 47 struct EduState { 48 PCIDevice pdev; 49 MemoryRegion mmio; 50 51 QemuThread thread; 52 QemuMutex thr_mutex; 53 QemuCond thr_cond; 54 bool stopping; 55 56 uint32_t addr4; 57 uint32_t fact; 58 #define EDU_STATUS_COMPUTING 0x01 59 #define EDU_STATUS_IRQFACT 0x80 60 uint32_t status; 61 62 uint32_t irq_status; 63 64 #define EDU_DMA_RUN 0x1 65 #define EDU_DMA_DIR(cmd) (((cmd) & 0x2) >> 1) 66 # define EDU_DMA_FROM_PCI 0 67 # define EDU_DMA_TO_PCI 1 68 #define EDU_DMA_IRQ 0x4 69 struct dma_state { 70 dma_addr_t src; 71 dma_addr_t dst; 72 dma_addr_t cnt; 73 dma_addr_t cmd; 74 } dma; 75 QEMUTimer dma_timer; 76 char dma_buf[DMA_SIZE]; 77 uint64_t dma_mask; 78 }; 79 80 static bool edu_msi_enabled(EduState *edu) 81 { 82 return msi_enabled(&edu->pdev); 83 } 84 85 static void edu_raise_irq(EduState *edu, uint32_t val) 86 { 87 edu->irq_status |= val; 88 if (edu->irq_status) { 89 if (edu_msi_enabled(edu)) { 90 msi_notify(&edu->pdev, 0); 91 } else { 92 pci_set_irq(&edu->pdev, 1); 93 } 94 } 95 } 96 97 static void edu_lower_irq(EduState *edu, uint32_t val) 98 { 99 edu->irq_status &= ~val; 100 101 if (!edu->irq_status && !edu_msi_enabled(edu)) { 102 pci_set_irq(&edu->pdev, 0); 103 } 104 } 105 106 static bool within(uint64_t addr, uint64_t start, uint64_t end) 107 { 108 return start <= addr && addr < end; 109 } 110 111 static void edu_check_range(uint64_t addr, uint64_t size1, uint64_t start, 112 uint64_t size2) 113 { 114 uint64_t end1 = addr + size1; 115 uint64_t end2 = start + size2; 116 117 if (within(addr, start, end2) && 118 end1 > addr && within(end1, start, end2)) { 119 return; 120 } 121 122 hw_error("EDU: DMA range 0x%016"PRIx64"-0x%016"PRIx64 123 " out of bounds (0x%016"PRIx64"-0x%016"PRIx64")!", 124 addr, end1 - 1, start, end2 - 1); 125 } 126 127 static dma_addr_t edu_clamp_addr(const EduState *edu, dma_addr_t addr) 128 { 129 dma_addr_t res = addr & edu->dma_mask; 130 131 if (addr != res) { 132 printf("EDU: clamping DMA %#.16"PRIx64" to %#.16"PRIx64"!\n", addr, res); 133 } 134 135 return res; 136 } 137 138 static void edu_dma_timer(void *opaque) 139 { 140 EduState *edu = opaque; 141 bool raise_irq = false; 142 143 if (!(edu->dma.cmd & EDU_DMA_RUN)) { 144 return; 145 } 146 147 if (EDU_DMA_DIR(edu->dma.cmd) == EDU_DMA_FROM_PCI) { 148 uint64_t dst = edu->dma.dst; 149 edu_check_range(dst, edu->dma.cnt, DMA_START, DMA_SIZE); 150 dst -= DMA_START; 151 pci_dma_read(&edu->pdev, edu_clamp_addr(edu, edu->dma.src), 152 edu->dma_buf + dst, edu->dma.cnt); 153 } else { 154 uint64_t src = edu->dma.src; 155 edu_check_range(src, edu->dma.cnt, DMA_START, DMA_SIZE); 156 src -= DMA_START; 157 pci_dma_write(&edu->pdev, edu_clamp_addr(edu, edu->dma.dst), 158 edu->dma_buf + src, edu->dma.cnt); 159 } 160 161 edu->dma.cmd &= ~EDU_DMA_RUN; 162 if (edu->dma.cmd & EDU_DMA_IRQ) { 163 raise_irq = true; 164 } 165 166 if (raise_irq) { 167 edu_raise_irq(edu, DMA_IRQ); 168 } 169 } 170 171 static void dma_rw(EduState *edu, bool write, dma_addr_t *val, dma_addr_t *dma, 172 bool timer) 173 { 174 if (write && (edu->dma.cmd & EDU_DMA_RUN)) { 175 return; 176 } 177 178 if (write) { 179 *dma = *val; 180 } else { 181 *val = *dma; 182 } 183 184 if (timer) { 185 timer_mod(&edu->dma_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + 100); 186 } 187 } 188 189 static uint64_t edu_mmio_read(void *opaque, hwaddr addr, unsigned size) 190 { 191 EduState *edu = opaque; 192 uint64_t val = ~0ULL; 193 194 if (addr < 0x80 && size != 4) { 195 return val; 196 } 197 198 if (addr >= 0x80 && size != 4 && size != 8) { 199 return val; 200 } 201 202 switch (addr) { 203 case 0x00: 204 val = 0x010000edu; 205 break; 206 case 0x04: 207 val = edu->addr4; 208 break; 209 case 0x08: 210 qemu_mutex_lock(&edu->thr_mutex); 211 val = edu->fact; 212 qemu_mutex_unlock(&edu->thr_mutex); 213 break; 214 case 0x20: 215 val = atomic_read(&edu->status); 216 break; 217 case 0x24: 218 val = edu->irq_status; 219 break; 220 case 0x80: 221 dma_rw(edu, false, &val, &edu->dma.src, false); 222 break; 223 case 0x88: 224 dma_rw(edu, false, &val, &edu->dma.dst, false); 225 break; 226 case 0x90: 227 dma_rw(edu, false, &val, &edu->dma.cnt, false); 228 break; 229 case 0x98: 230 dma_rw(edu, false, &val, &edu->dma.cmd, false); 231 break; 232 } 233 234 return val; 235 } 236 237 static void edu_mmio_write(void *opaque, hwaddr addr, uint64_t val, 238 unsigned size) 239 { 240 EduState *edu = opaque; 241 242 if (addr < 0x80 && size != 4) { 243 return; 244 } 245 246 if (addr >= 0x80 && size != 4 && size != 8) { 247 return; 248 } 249 250 switch (addr) { 251 case 0x04: 252 edu->addr4 = ~val; 253 break; 254 case 0x08: 255 if (atomic_read(&edu->status) & EDU_STATUS_COMPUTING) { 256 break; 257 } 258 /* EDU_STATUS_COMPUTING cannot go 0->1 concurrently, because it is only 259 * set in this function and it is under the iothread mutex. 260 */ 261 qemu_mutex_lock(&edu->thr_mutex); 262 edu->fact = val; 263 atomic_or(&edu->status, EDU_STATUS_COMPUTING); 264 qemu_cond_signal(&edu->thr_cond); 265 qemu_mutex_unlock(&edu->thr_mutex); 266 break; 267 case 0x20: 268 if (val & EDU_STATUS_IRQFACT) { 269 atomic_or(&edu->status, EDU_STATUS_IRQFACT); 270 } else { 271 atomic_and(&edu->status, ~EDU_STATUS_IRQFACT); 272 } 273 break; 274 case 0x60: 275 edu_raise_irq(edu, val); 276 break; 277 case 0x64: 278 edu_lower_irq(edu, val); 279 break; 280 case 0x80: 281 dma_rw(edu, true, &val, &edu->dma.src, false); 282 break; 283 case 0x88: 284 dma_rw(edu, true, &val, &edu->dma.dst, false); 285 break; 286 case 0x90: 287 dma_rw(edu, true, &val, &edu->dma.cnt, false); 288 break; 289 case 0x98: 290 if (!(val & EDU_DMA_RUN)) { 291 break; 292 } 293 dma_rw(edu, true, &val, &edu->dma.cmd, true); 294 break; 295 } 296 } 297 298 static const MemoryRegionOps edu_mmio_ops = { 299 .read = edu_mmio_read, 300 .write = edu_mmio_write, 301 .endianness = DEVICE_NATIVE_ENDIAN, 302 .valid = { 303 .min_access_size = 4, 304 .max_access_size = 8, 305 }, 306 .impl = { 307 .min_access_size = 4, 308 .max_access_size = 8, 309 }, 310 311 }; 312 313 /* 314 * We purposely use a thread, so that users are forced to wait for the status 315 * register. 316 */ 317 static void *edu_fact_thread(void *opaque) 318 { 319 EduState *edu = opaque; 320 321 while (1) { 322 uint32_t val, ret = 1; 323 324 qemu_mutex_lock(&edu->thr_mutex); 325 while ((atomic_read(&edu->status) & EDU_STATUS_COMPUTING) == 0 && 326 !edu->stopping) { 327 qemu_cond_wait(&edu->thr_cond, &edu->thr_mutex); 328 } 329 330 if (edu->stopping) { 331 qemu_mutex_unlock(&edu->thr_mutex); 332 break; 333 } 334 335 val = edu->fact; 336 qemu_mutex_unlock(&edu->thr_mutex); 337 338 while (val > 0) { 339 ret *= val--; 340 } 341 342 /* 343 * We should sleep for a random period here, so that students are 344 * forced to check the status properly. 345 */ 346 347 qemu_mutex_lock(&edu->thr_mutex); 348 edu->fact = ret; 349 qemu_mutex_unlock(&edu->thr_mutex); 350 atomic_and(&edu->status, ~EDU_STATUS_COMPUTING); 351 352 if (atomic_read(&edu->status) & EDU_STATUS_IRQFACT) { 353 qemu_mutex_lock_iothread(); 354 edu_raise_irq(edu, FACT_IRQ); 355 qemu_mutex_unlock_iothread(); 356 } 357 } 358 359 return NULL; 360 } 361 362 static void pci_edu_realize(PCIDevice *pdev, Error **errp) 363 { 364 EduState *edu = EDU(pdev); 365 uint8_t *pci_conf = pdev->config; 366 367 pci_config_set_interrupt_pin(pci_conf, 1); 368 369 if (msi_init(pdev, 0, 1, true, false, errp)) { 370 return; 371 } 372 373 timer_init_ms(&edu->dma_timer, QEMU_CLOCK_VIRTUAL, edu_dma_timer, edu); 374 375 qemu_mutex_init(&edu->thr_mutex); 376 qemu_cond_init(&edu->thr_cond); 377 qemu_thread_create(&edu->thread, "edu", edu_fact_thread, 378 edu, QEMU_THREAD_JOINABLE); 379 380 memory_region_init_io(&edu->mmio, OBJECT(edu), &edu_mmio_ops, edu, 381 "edu-mmio", 1 * MiB); 382 pci_register_bar(pdev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &edu->mmio); 383 } 384 385 static void pci_edu_uninit(PCIDevice *pdev) 386 { 387 EduState *edu = EDU(pdev); 388 389 qemu_mutex_lock(&edu->thr_mutex); 390 edu->stopping = true; 391 qemu_mutex_unlock(&edu->thr_mutex); 392 qemu_cond_signal(&edu->thr_cond); 393 qemu_thread_join(&edu->thread); 394 395 qemu_cond_destroy(&edu->thr_cond); 396 qemu_mutex_destroy(&edu->thr_mutex); 397 398 timer_del(&edu->dma_timer); 399 msi_uninit(pdev); 400 } 401 402 static void edu_instance_init(Object *obj) 403 { 404 EduState *edu = EDU(obj); 405 406 edu->dma_mask = (1UL << 28) - 1; 407 object_property_add_uint64_ptr(obj, "dma_mask", 408 &edu->dma_mask, OBJ_PROP_FLAG_READWRITE); 409 } 410 411 static void edu_class_init(ObjectClass *class, void *data) 412 { 413 DeviceClass *dc = DEVICE_CLASS(class); 414 PCIDeviceClass *k = PCI_DEVICE_CLASS(class); 415 416 k->realize = pci_edu_realize; 417 k->exit = pci_edu_uninit; 418 k->vendor_id = PCI_VENDOR_ID_QEMU; 419 k->device_id = 0x11e8; 420 k->revision = 0x10; 421 k->class_id = PCI_CLASS_OTHERS; 422 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 423 } 424 425 static void pci_edu_register_types(void) 426 { 427 static InterfaceInfo interfaces[] = { 428 { INTERFACE_CONVENTIONAL_PCI_DEVICE }, 429 { }, 430 }; 431 static const TypeInfo edu_info = { 432 .name = TYPE_PCI_EDU_DEVICE, 433 .parent = TYPE_PCI_DEVICE, 434 .instance_size = sizeof(EduState), 435 .instance_init = edu_instance_init, 436 .class_init = edu_class_init, 437 .interfaces = interfaces, 438 }; 439 440 type_register_static(&edu_info); 441 } 442 type_init(pci_edu_register_types) 443