1 /* 2 * Virtio memory mapped device driver 3 * 4 * Copyright 2011, ARM Ltd. 5 * 6 * This module allows virtio devices to be used over a virtual, memory mapped 7 * platform device. 8 * 9 * The guest device(s) may be instantiated in one of three equivalent ways: 10 * 11 * 1. Static platform device in board's code, eg.: 12 * 13 * static struct platform_device v2m_virtio_device = { 14 * .name = "virtio-mmio", 15 * .id = -1, 16 * .num_resources = 2, 17 * .resource = (struct resource []) { 18 * { 19 * .start = 0x1001e000, 20 * .end = 0x1001e0ff, 21 * .flags = IORESOURCE_MEM, 22 * }, { 23 * .start = 42 + 32, 24 * .end = 42 + 32, 25 * .flags = IORESOURCE_IRQ, 26 * }, 27 * } 28 * }; 29 * 30 * 2. Device Tree node, eg.: 31 * 32 * virtio_block@1e000 { 33 * compatible = "virtio,mmio"; 34 * reg = <0x1e000 0x100>; 35 * interrupts = <42>; 36 * } 37 * 38 * 3. Kernel module (or command line) parameter. Can be used more than once - 39 * one device will be created for each one. Syntax: 40 * 41 * [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>] 42 * where: 43 * <size> := size (can use standard suffixes like K, M or G) 44 * <baseaddr> := physical base address 45 * <irq> := interrupt number (as passed to request_irq()) 46 * <id> := (optional) platform device id 47 * eg.: 48 * virtio_mmio.device=0x100@0x100b0000:48 \ 49 * virtio_mmio.device=1K@0x1001e000:74 50 * 51 * 52 * 53 * Registers layout (all 32-bit wide): 54 * 55 * offset d. name description 56 * ------ -- ---------------- ----------------- 57 * 58 * 0x000 R MagicValue Magic value "virt" 59 * 0x004 R Version Device version (current max. 1) 60 * 0x008 R DeviceID Virtio device ID 61 * 0x00c R VendorID Virtio vendor ID 62 * 63 * 0x010 R HostFeatures Features supported by the host 64 * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures 65 * 66 * 0x020 W GuestFeatures Features activated by the guest 67 * 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures 68 * 0x028 W GuestPageSize Size of guest's memory page in bytes 69 * 70 * 0x030 W QueueSel Queue selector 71 * 0x034 R QueueNumMax Maximum size of the currently selected queue 72 * 0x038 W QueueNum Queue size for the currently selected queue 73 * 0x03c W QueueAlign Used Ring alignment for the current queue 74 * 0x040 RW QueuePFN PFN for the currently selected queue 75 * 76 * 0x050 W QueueNotify Queue notifier 77 * 0x060 R InterruptStatus Interrupt status register 78 * 0x060 W InterruptACK Interrupt acknowledge register 79 * 0x070 RW Status Device status register 80 * 81 * 0x100+ RW Device-specific configuration space 82 * 83 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007 84 * 85 * This work is licensed under the terms of the GNU GPL, version 2 or later. 86 * See the COPYING file in the top-level directory. 87 */ 88 89 #define pr_fmt(fmt) "virtio-mmio: " fmt 90 91 #include <linux/highmem.h> 92 #include <linux/interrupt.h> 93 #include <linux/io.h> 94 #include <linux/list.h> 95 #include <linux/module.h> 96 #include <linux/platform_device.h> 97 #include <linux/slab.h> 98 #include <linux/spinlock.h> 99 #include <linux/virtio.h> 100 #include <linux/virtio_config.h> 101 #include <linux/virtio_mmio.h> 102 #include <linux/virtio_ring.h> 103 104 105 106 /* The alignment to use between consumer and producer parts of vring. 107 * Currently hardcoded to the page size. */ 108 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE 109 110 111 112 #define to_virtio_mmio_device(_plat_dev) \ 113 container_of(_plat_dev, struct virtio_mmio_device, vdev) 114 115 struct virtio_mmio_device { 116 struct virtio_device vdev; 117 struct platform_device *pdev; 118 119 void __iomem *base; 120 unsigned long version; 121 122 /* a list of queues so we can dispatch IRQs */ 123 spinlock_t lock; 124 struct list_head virtqueues; 125 }; 126 127 struct virtio_mmio_vq_info { 128 /* the actual virtqueue */ 129 struct virtqueue *vq; 130 131 /* the number of entries in the queue */ 132 unsigned int num; 133 134 /* the index of the queue */ 135 int queue_index; 136 137 /* the virtual address of the ring queue */ 138 void *queue; 139 140 /* the list node for the virtqueues list */ 141 struct list_head node; 142 }; 143 144 145 146 /* Configuration interface */ 147 148 static u32 vm_get_features(struct virtio_device *vdev) 149 { 150 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 151 152 /* TODO: Features > 32 bits */ 153 writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL); 154 155 return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES); 156 } 157 158 static void vm_finalize_features(struct virtio_device *vdev) 159 { 160 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 161 int i; 162 163 /* Give virtio_ring a chance to accept features. */ 164 vring_transport_features(vdev); 165 166 for (i = 0; i < ARRAY_SIZE(vdev->features); i++) { 167 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL); 168 writel(vdev->features[i], 169 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES); 170 } 171 } 172 173 static void vm_get(struct virtio_device *vdev, unsigned offset, 174 void *buf, unsigned len) 175 { 176 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 177 u8 *ptr = buf; 178 int i; 179 180 for (i = 0; i < len; i++) 181 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); 182 } 183 184 static void vm_set(struct virtio_device *vdev, unsigned offset, 185 const void *buf, unsigned len) 186 { 187 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 188 const u8 *ptr = buf; 189 int i; 190 191 for (i = 0; i < len; i++) 192 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); 193 } 194 195 static u8 vm_get_status(struct virtio_device *vdev) 196 { 197 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 198 199 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff; 200 } 201 202 static void vm_set_status(struct virtio_device *vdev, u8 status) 203 { 204 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 205 206 /* We should never be setting status to 0. */ 207 BUG_ON(status == 0); 208 209 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); 210 } 211 212 static void vm_reset(struct virtio_device *vdev) 213 { 214 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 215 216 /* 0 status means a reset. */ 217 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); 218 } 219 220 221 222 /* Transport interface */ 223 224 /* the notify function used when creating a virt queue */ 225 static void vm_notify(struct virtqueue *vq) 226 { 227 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 228 struct virtio_mmio_vq_info *info = vq->priv; 229 230 /* We write the queue's selector into the notification register to 231 * signal the other end */ 232 writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); 233 } 234 235 /* Notify all virtqueues on an interrupt. */ 236 static irqreturn_t vm_interrupt(int irq, void *opaque) 237 { 238 struct virtio_mmio_device *vm_dev = opaque; 239 struct virtio_mmio_vq_info *info; 240 struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver, 241 struct virtio_driver, driver); 242 unsigned long status; 243 unsigned long flags; 244 irqreturn_t ret = IRQ_NONE; 245 246 /* Read and acknowledge interrupts */ 247 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); 248 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); 249 250 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG) 251 && vdrv && vdrv->config_changed) { 252 vdrv->config_changed(&vm_dev->vdev); 253 ret = IRQ_HANDLED; 254 } 255 256 if (likely(status & VIRTIO_MMIO_INT_VRING)) { 257 spin_lock_irqsave(&vm_dev->lock, flags); 258 list_for_each_entry(info, &vm_dev->virtqueues, node) 259 ret |= vring_interrupt(irq, info->vq); 260 spin_unlock_irqrestore(&vm_dev->lock, flags); 261 } 262 263 return ret; 264 } 265 266 267 268 static void vm_del_vq(struct virtqueue *vq) 269 { 270 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 271 struct virtio_mmio_vq_info *info = vq->priv; 272 unsigned long flags, size; 273 274 spin_lock_irqsave(&vm_dev->lock, flags); 275 list_del(&info->node); 276 spin_unlock_irqrestore(&vm_dev->lock, flags); 277 278 vring_del_virtqueue(vq); 279 280 /* Select and deactivate the queue */ 281 writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 282 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 283 284 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); 285 free_pages_exact(info->queue, size); 286 kfree(info); 287 } 288 289 static void vm_del_vqs(struct virtio_device *vdev) 290 { 291 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 292 struct virtqueue *vq, *n; 293 294 list_for_each_entry_safe(vq, n, &vdev->vqs, list) 295 vm_del_vq(vq); 296 297 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev); 298 } 299 300 301 302 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, 303 void (*callback)(struct virtqueue *vq), 304 const char *name) 305 { 306 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 307 struct virtio_mmio_vq_info *info; 308 struct virtqueue *vq; 309 unsigned long flags, size; 310 int err; 311 312 /* Select the queue we're interested in */ 313 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 314 315 /* Queue shouldn't already be set up. */ 316 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) { 317 err = -ENOENT; 318 goto error_available; 319 } 320 321 /* Allocate and fill out our active queue description */ 322 info = kmalloc(sizeof(*info), GFP_KERNEL); 323 if (!info) { 324 err = -ENOMEM; 325 goto error_kmalloc; 326 } 327 info->queue_index = index; 328 329 /* Allocate pages for the queue - start with a queue as big as 330 * possible (limited by maximum size allowed by device), drop down 331 * to a minimal size, just big enough to fit descriptor table 332 * and two rings (which makes it "alignment_size * 2") 333 */ 334 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); 335 while (1) { 336 size = PAGE_ALIGN(vring_size(info->num, 337 VIRTIO_MMIO_VRING_ALIGN)); 338 /* Already smallest possible allocation? */ 339 if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) { 340 err = -ENOMEM; 341 goto error_alloc_pages; 342 } 343 344 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); 345 if (info->queue) 346 break; 347 348 info->num /= 2; 349 } 350 351 /* Activate the queue */ 352 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); 353 writel(VIRTIO_MMIO_VRING_ALIGN, 354 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); 355 writel(virt_to_phys(info->queue) >> PAGE_SHIFT, 356 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 357 358 /* Create the vring */ 359 vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, vdev, 360 true, info->queue, vm_notify, callback, name); 361 if (!vq) { 362 err = -ENOMEM; 363 goto error_new_virtqueue; 364 } 365 366 vq->priv = info; 367 info->vq = vq; 368 369 spin_lock_irqsave(&vm_dev->lock, flags); 370 list_add(&info->node, &vm_dev->virtqueues); 371 spin_unlock_irqrestore(&vm_dev->lock, flags); 372 373 return vq; 374 375 error_new_virtqueue: 376 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 377 free_pages_exact(info->queue, size); 378 error_alloc_pages: 379 kfree(info); 380 error_kmalloc: 381 error_available: 382 return ERR_PTR(err); 383 } 384 385 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, 386 struct virtqueue *vqs[], 387 vq_callback_t *callbacks[], 388 const char *names[]) 389 { 390 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 391 unsigned int irq = platform_get_irq(vm_dev->pdev, 0); 392 int i, err; 393 394 err = request_irq(irq, vm_interrupt, IRQF_SHARED, 395 dev_name(&vdev->dev), vm_dev); 396 if (err) 397 return err; 398 399 for (i = 0; i < nvqs; ++i) { 400 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]); 401 if (IS_ERR(vqs[i])) { 402 vm_del_vqs(vdev); 403 return PTR_ERR(vqs[i]); 404 } 405 } 406 407 return 0; 408 } 409 410 static const char *vm_bus_name(struct virtio_device *vdev) 411 { 412 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 413 414 return vm_dev->pdev->name; 415 } 416 417 static struct virtio_config_ops virtio_mmio_config_ops = { 418 .get = vm_get, 419 .set = vm_set, 420 .get_status = vm_get_status, 421 .set_status = vm_set_status, 422 .reset = vm_reset, 423 .find_vqs = vm_find_vqs, 424 .del_vqs = vm_del_vqs, 425 .get_features = vm_get_features, 426 .finalize_features = vm_finalize_features, 427 .bus_name = vm_bus_name, 428 }; 429 430 431 432 /* Platform device */ 433 434 static int __devinit virtio_mmio_probe(struct platform_device *pdev) 435 { 436 struct virtio_mmio_device *vm_dev; 437 struct resource *mem; 438 unsigned long magic; 439 440 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 441 if (!mem) 442 return -EINVAL; 443 444 if (!devm_request_mem_region(&pdev->dev, mem->start, 445 resource_size(mem), pdev->name)) 446 return -EBUSY; 447 448 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); 449 if (!vm_dev) 450 return -ENOMEM; 451 452 vm_dev->vdev.dev.parent = &pdev->dev; 453 vm_dev->vdev.config = &virtio_mmio_config_ops; 454 vm_dev->pdev = pdev; 455 INIT_LIST_HEAD(&vm_dev->virtqueues); 456 spin_lock_init(&vm_dev->lock); 457 458 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); 459 if (vm_dev->base == NULL) 460 return -EFAULT; 461 462 /* Check magic value */ 463 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); 464 if (memcmp(&magic, "virt", 4) != 0) { 465 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); 466 return -ENODEV; 467 } 468 469 /* Check device version */ 470 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); 471 if (vm_dev->version != 1) { 472 dev_err(&pdev->dev, "Version %ld not supported!\n", 473 vm_dev->version); 474 return -ENXIO; 475 } 476 477 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); 478 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); 479 480 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); 481 482 platform_set_drvdata(pdev, vm_dev); 483 484 return register_virtio_device(&vm_dev->vdev); 485 } 486 487 static int __devexit virtio_mmio_remove(struct platform_device *pdev) 488 { 489 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); 490 491 unregister_virtio_device(&vm_dev->vdev); 492 493 return 0; 494 } 495 496 497 498 /* Devices list parameter */ 499 500 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES) 501 502 static struct device vm_cmdline_parent = { 503 .init_name = "virtio-mmio-cmdline", 504 }; 505 506 static int vm_cmdline_parent_registered; 507 static int vm_cmdline_id; 508 509 static int vm_cmdline_set(const char *device, 510 const struct kernel_param *kp) 511 { 512 int err; 513 struct resource resources[2] = {}; 514 char *str; 515 long long int base; 516 int processed, consumed = 0; 517 struct platform_device *pdev; 518 519 resources[0].flags = IORESOURCE_MEM; 520 resources[1].flags = IORESOURCE_IRQ; 521 522 resources[0].end = memparse(device, &str) - 1; 523 524 processed = sscanf(str, "@%lli:%u%n:%d%n", 525 &base, &resources[1].start, &consumed, 526 &vm_cmdline_id, &consumed); 527 528 if (processed < 2 || processed > 3 || str[consumed]) 529 return -EINVAL; 530 531 resources[0].start = base; 532 resources[0].end += base; 533 resources[1].end = resources[1].start; 534 535 if (!vm_cmdline_parent_registered) { 536 err = device_register(&vm_cmdline_parent); 537 if (err) { 538 pr_err("Failed to register parent device!\n"); 539 return err; 540 } 541 vm_cmdline_parent_registered = 1; 542 } 543 544 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n", 545 vm_cmdline_id, 546 (unsigned long long)resources[0].start, 547 (unsigned long long)resources[0].end, 548 (int)resources[1].start); 549 550 pdev = platform_device_register_resndata(&vm_cmdline_parent, 551 "virtio-mmio", vm_cmdline_id++, 552 resources, ARRAY_SIZE(resources), NULL, 0); 553 if (IS_ERR(pdev)) 554 return PTR_ERR(pdev); 555 556 return 0; 557 } 558 559 static int vm_cmdline_get_device(struct device *dev, void *data) 560 { 561 char *buffer = data; 562 unsigned int len = strlen(buffer); 563 struct platform_device *pdev = to_platform_device(dev); 564 565 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n", 566 pdev->resource[0].end - pdev->resource[0].start + 1ULL, 567 (unsigned long long)pdev->resource[0].start, 568 (unsigned long long)pdev->resource[1].start, 569 pdev->id); 570 return 0; 571 } 572 573 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp) 574 { 575 buffer[0] = '\0'; 576 device_for_each_child(&vm_cmdline_parent, buffer, 577 vm_cmdline_get_device); 578 return strlen(buffer) + 1; 579 } 580 581 static struct kernel_param_ops vm_cmdline_param_ops = { 582 .set = vm_cmdline_set, 583 .get = vm_cmdline_get, 584 }; 585 586 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR); 587 588 static int vm_unregister_cmdline_device(struct device *dev, 589 void *data) 590 { 591 platform_device_unregister(to_platform_device(dev)); 592 593 return 0; 594 } 595 596 static void vm_unregister_cmdline_devices(void) 597 { 598 if (vm_cmdline_parent_registered) { 599 device_for_each_child(&vm_cmdline_parent, NULL, 600 vm_unregister_cmdline_device); 601 device_unregister(&vm_cmdline_parent); 602 vm_cmdline_parent_registered = 0; 603 } 604 } 605 606 #else 607 608 static void vm_unregister_cmdline_devices(void) 609 { 610 } 611 612 #endif 613 614 /* Platform driver */ 615 616 static struct of_device_id virtio_mmio_match[] = { 617 { .compatible = "virtio,mmio", }, 618 {}, 619 }; 620 MODULE_DEVICE_TABLE(of, virtio_mmio_match); 621 622 static struct platform_driver virtio_mmio_driver = { 623 .probe = virtio_mmio_probe, 624 .remove = __devexit_p(virtio_mmio_remove), 625 .driver = { 626 .name = "virtio-mmio", 627 .owner = THIS_MODULE, 628 .of_match_table = virtio_mmio_match, 629 }, 630 }; 631 632 static int __init virtio_mmio_init(void) 633 { 634 return platform_driver_register(&virtio_mmio_driver); 635 } 636 637 static void __exit virtio_mmio_exit(void) 638 { 639 platform_driver_unregister(&virtio_mmio_driver); 640 vm_unregister_cmdline_devices(); 641 } 642 643 module_init(virtio_mmio_init); 644 module_exit(virtio_mmio_exit); 645 646 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>"); 647 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices"); 648 MODULE_LICENSE("GPL"); 649