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 = qatomic_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 (qatomic_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 qatomic_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 qatomic_or(&edu->status, EDU_STATUS_IRQFACT); 270 /* Order check of the COMPUTING flag after setting IRQFACT. */ 271 smp_mb__after_rmw(); 272 } else { 273 qatomic_and(&edu->status, ~EDU_STATUS_IRQFACT); 274 } 275 break; 276 case 0x60: 277 edu_raise_irq(edu, val); 278 break; 279 case 0x64: 280 edu_lower_irq(edu, val); 281 break; 282 case 0x80: 283 dma_rw(edu, true, &val, &edu->dma.src, false); 284 break; 285 case 0x88: 286 dma_rw(edu, true, &val, &edu->dma.dst, false); 287 break; 288 case 0x90: 289 dma_rw(edu, true, &val, &edu->dma.cnt, false); 290 break; 291 case 0x98: 292 if (!(val & EDU_DMA_RUN)) { 293 break; 294 } 295 dma_rw(edu, true, &val, &edu->dma.cmd, true); 296 break; 297 } 298 } 299 300 static const MemoryRegionOps edu_mmio_ops = { 301 .read = edu_mmio_read, 302 .write = edu_mmio_write, 303 .endianness = DEVICE_NATIVE_ENDIAN, 304 .valid = { 305 .min_access_size = 4, 306 .max_access_size = 8, 307 }, 308 .impl = { 309 .min_access_size = 4, 310 .max_access_size = 8, 311 }, 312 313 }; 314 315 /* 316 * We purposely use a thread, so that users are forced to wait for the status 317 * register. 318 */ 319 static void *edu_fact_thread(void *opaque) 320 { 321 EduState *edu = opaque; 322 323 while (1) { 324 uint32_t val, ret = 1; 325 326 qemu_mutex_lock(&edu->thr_mutex); 327 while ((qatomic_read(&edu->status) & EDU_STATUS_COMPUTING) == 0 && 328 !edu->stopping) { 329 qemu_cond_wait(&edu->thr_cond, &edu->thr_mutex); 330 } 331 332 if (edu->stopping) { 333 qemu_mutex_unlock(&edu->thr_mutex); 334 break; 335 } 336 337 val = edu->fact; 338 qemu_mutex_unlock(&edu->thr_mutex); 339 340 while (val > 0) { 341 ret *= val--; 342 } 343 344 /* 345 * We should sleep for a random period here, so that students are 346 * forced to check the status properly. 347 */ 348 349 qemu_mutex_lock(&edu->thr_mutex); 350 edu->fact = ret; 351 qemu_mutex_unlock(&edu->thr_mutex); 352 qatomic_and(&edu->status, ~EDU_STATUS_COMPUTING); 353 354 /* Clear COMPUTING flag before checking IRQFACT. */ 355 smp_mb__after_rmw(); 356 357 if (qatomic_read(&edu->status) & EDU_STATUS_IRQFACT) { 358 qemu_mutex_lock_iothread(); 359 edu_raise_irq(edu, FACT_IRQ); 360 qemu_mutex_unlock_iothread(); 361 } 362 } 363 364 return NULL; 365 } 366 367 static void pci_edu_realize(PCIDevice *pdev, Error **errp) 368 { 369 EduState *edu = EDU(pdev); 370 uint8_t *pci_conf = pdev->config; 371 372 pci_config_set_interrupt_pin(pci_conf, 1); 373 374 if (msi_init(pdev, 0, 1, true, false, errp)) { 375 return; 376 } 377 378 timer_init_ms(&edu->dma_timer, QEMU_CLOCK_VIRTUAL, edu_dma_timer, edu); 379 380 qemu_mutex_init(&edu->thr_mutex); 381 qemu_cond_init(&edu->thr_cond); 382 qemu_thread_create(&edu->thread, "edu", edu_fact_thread, 383 edu, QEMU_THREAD_JOINABLE); 384 385 memory_region_init_io(&edu->mmio, OBJECT(edu), &edu_mmio_ops, edu, 386 "edu-mmio", 1 * MiB); 387 pci_register_bar(pdev, 0, PCI_BASE_ADDRESS_SPACE_MEMORY, &edu->mmio); 388 } 389 390 static void pci_edu_uninit(PCIDevice *pdev) 391 { 392 EduState *edu = EDU(pdev); 393 394 qemu_mutex_lock(&edu->thr_mutex); 395 edu->stopping = true; 396 qemu_mutex_unlock(&edu->thr_mutex); 397 qemu_cond_signal(&edu->thr_cond); 398 qemu_thread_join(&edu->thread); 399 400 qemu_cond_destroy(&edu->thr_cond); 401 qemu_mutex_destroy(&edu->thr_mutex); 402 403 timer_del(&edu->dma_timer); 404 msi_uninit(pdev); 405 } 406 407 static void edu_instance_init(Object *obj) 408 { 409 EduState *edu = EDU(obj); 410 411 edu->dma_mask = (1UL << 28) - 1; 412 object_property_add_uint64_ptr(obj, "dma_mask", 413 &edu->dma_mask, OBJ_PROP_FLAG_READWRITE); 414 } 415 416 static void edu_class_init(ObjectClass *class, void *data) 417 { 418 DeviceClass *dc = DEVICE_CLASS(class); 419 PCIDeviceClass *k = PCI_DEVICE_CLASS(class); 420 421 k->realize = pci_edu_realize; 422 k->exit = pci_edu_uninit; 423 k->vendor_id = PCI_VENDOR_ID_QEMU; 424 k->device_id = 0x11e8; 425 k->revision = 0x10; 426 k->class_id = PCI_CLASS_OTHERS; 427 set_bit(DEVICE_CATEGORY_MISC, dc->categories); 428 } 429 430 static void pci_edu_register_types(void) 431 { 432 static InterfaceInfo interfaces[] = { 433 { INTERFACE_CONVENTIONAL_PCI_DEVICE }, 434 { }, 435 }; 436 static const TypeInfo edu_info = { 437 .name = TYPE_PCI_EDU_DEVICE, 438 .parent = TYPE_PCI_DEVICE, 439 .instance_size = sizeof(EduState), 440 .instance_init = edu_instance_init, 441 .class_init = edu_class_init, 442 .interfaces = interfaces, 443 }; 444 445 type_register_static(&edu_info); 446 } 447 type_init(pci_edu_register_types) 448