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 * 0x064 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 virtual address of the ring queue */ 135 void *queue; 136 137 /* the list node for the virtqueues list */ 138 struct list_head node; 139 }; 140 141 142 143 /* Configuration interface */ 144 145 static u64 vm_get_features(struct virtio_device *vdev) 146 { 147 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 148 149 /* TODO: Features > 32 bits */ 150 writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL); 151 152 return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES); 153 } 154 155 static int vm_finalize_features(struct virtio_device *vdev) 156 { 157 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 158 159 /* Give virtio_ring a chance to accept features. */ 160 vring_transport_features(vdev); 161 162 /* Make sure we don't have any features > 32 bits! */ 163 BUG_ON((u32)vdev->features != vdev->features); 164 165 writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL); 166 writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES); 167 168 return 0; 169 } 170 171 static void vm_get(struct virtio_device *vdev, unsigned offset, 172 void *buf, unsigned len) 173 { 174 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 175 u8 *ptr = buf; 176 int i; 177 178 for (i = 0; i < len; i++) 179 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); 180 } 181 182 static void vm_set(struct virtio_device *vdev, unsigned offset, 183 const void *buf, unsigned len) 184 { 185 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 186 const u8 *ptr = buf; 187 int i; 188 189 for (i = 0; i < len; i++) 190 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); 191 } 192 193 static u8 vm_get_status(struct virtio_device *vdev) 194 { 195 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 196 197 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff; 198 } 199 200 static void vm_set_status(struct virtio_device *vdev, u8 status) 201 { 202 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 203 204 /* We should never be setting status to 0. */ 205 BUG_ON(status == 0); 206 207 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); 208 } 209 210 static void vm_reset(struct virtio_device *vdev) 211 { 212 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 213 214 /* 0 status means a reset. */ 215 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); 216 } 217 218 219 220 /* Transport interface */ 221 222 /* the notify function used when creating a virt queue */ 223 static bool vm_notify(struct virtqueue *vq) 224 { 225 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 226 227 /* We write the queue's selector into the notification register to 228 * signal the other end */ 229 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); 230 return true; 231 } 232 233 /* Notify all virtqueues on an interrupt. */ 234 static irqreturn_t vm_interrupt(int irq, void *opaque) 235 { 236 struct virtio_mmio_device *vm_dev = opaque; 237 struct virtio_mmio_vq_info *info; 238 unsigned long status; 239 unsigned long flags; 240 irqreturn_t ret = IRQ_NONE; 241 242 /* Read and acknowledge interrupts */ 243 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); 244 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); 245 246 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) { 247 virtio_config_changed(&vm_dev->vdev); 248 ret = IRQ_HANDLED; 249 } 250 251 if (likely(status & VIRTIO_MMIO_INT_VRING)) { 252 spin_lock_irqsave(&vm_dev->lock, flags); 253 list_for_each_entry(info, &vm_dev->virtqueues, node) 254 ret |= vring_interrupt(irq, info->vq); 255 spin_unlock_irqrestore(&vm_dev->lock, flags); 256 } 257 258 return ret; 259 } 260 261 262 263 static void vm_del_vq(struct virtqueue *vq) 264 { 265 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 266 struct virtio_mmio_vq_info *info = vq->priv; 267 unsigned long flags, size; 268 unsigned int index = vq->index; 269 270 spin_lock_irqsave(&vm_dev->lock, flags); 271 list_del(&info->node); 272 spin_unlock_irqrestore(&vm_dev->lock, flags); 273 274 vring_del_virtqueue(vq); 275 276 /* Select and deactivate the queue */ 277 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 278 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 279 280 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); 281 free_pages_exact(info->queue, size); 282 kfree(info); 283 } 284 285 static void vm_del_vqs(struct virtio_device *vdev) 286 { 287 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 288 struct virtqueue *vq, *n; 289 290 list_for_each_entry_safe(vq, n, &vdev->vqs, list) 291 vm_del_vq(vq); 292 293 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev); 294 } 295 296 297 298 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, 299 void (*callback)(struct virtqueue *vq), 300 const char *name) 301 { 302 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 303 struct virtio_mmio_vq_info *info; 304 struct virtqueue *vq; 305 unsigned long flags, size; 306 int err; 307 308 if (!name) 309 return NULL; 310 311 /* Select the queue we're interested in */ 312 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 313 314 /* Queue shouldn't already be set up. */ 315 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) { 316 err = -ENOENT; 317 goto error_available; 318 } 319 320 /* Allocate and fill out our active queue description */ 321 info = kmalloc(sizeof(*info), GFP_KERNEL); 322 if (!info) { 323 err = -ENOMEM; 324 goto error_kmalloc; 325 } 326 327 /* Allocate pages for the queue - start with a queue as big as 328 * possible (limited by maximum size allowed by device), drop down 329 * to a minimal size, just big enough to fit descriptor table 330 * and two rings (which makes it "alignment_size * 2") 331 */ 332 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); 333 334 /* If the device reports a 0 entry queue, we won't be able to 335 * use it to perform I/O, and vring_new_virtqueue() can't create 336 * empty queues anyway, so don't bother to set up the device. 337 */ 338 if (info->num == 0) { 339 err = -ENOENT; 340 goto error_alloc_pages; 341 } 342 343 while (1) { 344 size = PAGE_ALIGN(vring_size(info->num, 345 VIRTIO_MMIO_VRING_ALIGN)); 346 /* Did the last iter shrink the queue below minimum size? */ 347 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) { 348 err = -ENOMEM; 349 goto error_alloc_pages; 350 } 351 352 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); 353 if (info->queue) 354 break; 355 356 info->num /= 2; 357 } 358 359 /* Activate the queue */ 360 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); 361 writel(VIRTIO_MMIO_VRING_ALIGN, 362 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); 363 writel(virt_to_phys(info->queue) >> PAGE_SHIFT, 364 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 365 366 /* Create the vring */ 367 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev, 368 true, info->queue, vm_notify, callback, name); 369 if (!vq) { 370 err = -ENOMEM; 371 goto error_new_virtqueue; 372 } 373 374 vq->priv = info; 375 info->vq = vq; 376 377 spin_lock_irqsave(&vm_dev->lock, flags); 378 list_add(&info->node, &vm_dev->virtqueues); 379 spin_unlock_irqrestore(&vm_dev->lock, flags); 380 381 return vq; 382 383 error_new_virtqueue: 384 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 385 free_pages_exact(info->queue, size); 386 error_alloc_pages: 387 kfree(info); 388 error_kmalloc: 389 error_available: 390 return ERR_PTR(err); 391 } 392 393 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, 394 struct virtqueue *vqs[], 395 vq_callback_t *callbacks[], 396 const char *names[]) 397 { 398 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 399 unsigned int irq = platform_get_irq(vm_dev->pdev, 0); 400 int i, err; 401 402 err = request_irq(irq, vm_interrupt, IRQF_SHARED, 403 dev_name(&vdev->dev), vm_dev); 404 if (err) 405 return err; 406 407 for (i = 0; i < nvqs; ++i) { 408 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]); 409 if (IS_ERR(vqs[i])) { 410 vm_del_vqs(vdev); 411 return PTR_ERR(vqs[i]); 412 } 413 } 414 415 return 0; 416 } 417 418 static const char *vm_bus_name(struct virtio_device *vdev) 419 { 420 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 421 422 return vm_dev->pdev->name; 423 } 424 425 static const struct virtio_config_ops virtio_mmio_config_ops = { 426 .get = vm_get, 427 .set = vm_set, 428 .get_status = vm_get_status, 429 .set_status = vm_set_status, 430 .reset = vm_reset, 431 .find_vqs = vm_find_vqs, 432 .del_vqs = vm_del_vqs, 433 .get_features = vm_get_features, 434 .finalize_features = vm_finalize_features, 435 .bus_name = vm_bus_name, 436 }; 437 438 439 440 /* Platform device */ 441 442 static int virtio_mmio_probe(struct platform_device *pdev) 443 { 444 struct virtio_mmio_device *vm_dev; 445 struct resource *mem; 446 unsigned long magic; 447 448 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 449 if (!mem) 450 return -EINVAL; 451 452 if (!devm_request_mem_region(&pdev->dev, mem->start, 453 resource_size(mem), pdev->name)) 454 return -EBUSY; 455 456 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); 457 if (!vm_dev) 458 return -ENOMEM; 459 460 vm_dev->vdev.dev.parent = &pdev->dev; 461 vm_dev->vdev.config = &virtio_mmio_config_ops; 462 vm_dev->pdev = pdev; 463 INIT_LIST_HEAD(&vm_dev->virtqueues); 464 spin_lock_init(&vm_dev->lock); 465 466 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); 467 if (vm_dev->base == NULL) 468 return -EFAULT; 469 470 /* Check magic value */ 471 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); 472 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) { 473 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); 474 return -ENODEV; 475 } 476 477 /* Check device version */ 478 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); 479 if (vm_dev->version != 1) { 480 dev_err(&pdev->dev, "Version %ld not supported!\n", 481 vm_dev->version); 482 return -ENXIO; 483 } 484 485 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); 486 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); 487 488 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); 489 490 platform_set_drvdata(pdev, vm_dev); 491 492 return register_virtio_device(&vm_dev->vdev); 493 } 494 495 static int virtio_mmio_remove(struct platform_device *pdev) 496 { 497 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); 498 499 unregister_virtio_device(&vm_dev->vdev); 500 501 return 0; 502 } 503 504 505 506 /* Devices list parameter */ 507 508 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES) 509 510 static struct device vm_cmdline_parent = { 511 .init_name = "virtio-mmio-cmdline", 512 }; 513 514 static int vm_cmdline_parent_registered; 515 static int vm_cmdline_id; 516 517 static int vm_cmdline_set(const char *device, 518 const struct kernel_param *kp) 519 { 520 int err; 521 struct resource resources[2] = {}; 522 char *str; 523 long long int base, size; 524 unsigned int irq; 525 int processed, consumed = 0; 526 struct platform_device *pdev; 527 528 /* Consume "size" part of the command line parameter */ 529 size = memparse(device, &str); 530 531 /* Get "@<base>:<irq>[:<id>]" chunks */ 532 processed = sscanf(str, "@%lli:%u%n:%d%n", 533 &base, &irq, &consumed, 534 &vm_cmdline_id, &consumed); 535 536 /* 537 * sscanf() must processes at least 2 chunks; also there 538 * must be no extra characters after the last chunk, so 539 * str[consumed] must be '\0' 540 */ 541 if (processed < 2 || str[consumed]) 542 return -EINVAL; 543 544 resources[0].flags = IORESOURCE_MEM; 545 resources[0].start = base; 546 resources[0].end = base + size - 1; 547 548 resources[1].flags = IORESOURCE_IRQ; 549 resources[1].start = resources[1].end = irq; 550 551 if (!vm_cmdline_parent_registered) { 552 err = device_register(&vm_cmdline_parent); 553 if (err) { 554 pr_err("Failed to register parent device!\n"); 555 return err; 556 } 557 vm_cmdline_parent_registered = 1; 558 } 559 560 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n", 561 vm_cmdline_id, 562 (unsigned long long)resources[0].start, 563 (unsigned long long)resources[0].end, 564 (int)resources[1].start); 565 566 pdev = platform_device_register_resndata(&vm_cmdline_parent, 567 "virtio-mmio", vm_cmdline_id++, 568 resources, ARRAY_SIZE(resources), NULL, 0); 569 if (IS_ERR(pdev)) 570 return PTR_ERR(pdev); 571 572 return 0; 573 } 574 575 static int vm_cmdline_get_device(struct device *dev, void *data) 576 { 577 char *buffer = data; 578 unsigned int len = strlen(buffer); 579 struct platform_device *pdev = to_platform_device(dev); 580 581 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n", 582 pdev->resource[0].end - pdev->resource[0].start + 1ULL, 583 (unsigned long long)pdev->resource[0].start, 584 (unsigned long long)pdev->resource[1].start, 585 pdev->id); 586 return 0; 587 } 588 589 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp) 590 { 591 buffer[0] = '\0'; 592 device_for_each_child(&vm_cmdline_parent, buffer, 593 vm_cmdline_get_device); 594 return strlen(buffer) + 1; 595 } 596 597 static struct kernel_param_ops vm_cmdline_param_ops = { 598 .set = vm_cmdline_set, 599 .get = vm_cmdline_get, 600 }; 601 602 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR); 603 604 static int vm_unregister_cmdline_device(struct device *dev, 605 void *data) 606 { 607 platform_device_unregister(to_platform_device(dev)); 608 609 return 0; 610 } 611 612 static void vm_unregister_cmdline_devices(void) 613 { 614 if (vm_cmdline_parent_registered) { 615 device_for_each_child(&vm_cmdline_parent, NULL, 616 vm_unregister_cmdline_device); 617 device_unregister(&vm_cmdline_parent); 618 vm_cmdline_parent_registered = 0; 619 } 620 } 621 622 #else 623 624 static void vm_unregister_cmdline_devices(void) 625 { 626 } 627 628 #endif 629 630 /* Platform driver */ 631 632 static struct of_device_id virtio_mmio_match[] = { 633 { .compatible = "virtio,mmio", }, 634 {}, 635 }; 636 MODULE_DEVICE_TABLE(of, virtio_mmio_match); 637 638 static struct platform_driver virtio_mmio_driver = { 639 .probe = virtio_mmio_probe, 640 .remove = virtio_mmio_remove, 641 .driver = { 642 .name = "virtio-mmio", 643 .of_match_table = virtio_mmio_match, 644 }, 645 }; 646 647 static int __init virtio_mmio_init(void) 648 { 649 return platform_driver_register(&virtio_mmio_driver); 650 } 651 652 static void __exit virtio_mmio_exit(void) 653 { 654 platform_driver_unregister(&virtio_mmio_driver); 655 vm_unregister_cmdline_devices(); 656 } 657 658 module_init(virtio_mmio_init); 659 module_exit(virtio_mmio_exit); 660 661 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>"); 662 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices"); 663 MODULE_LICENSE("GPL"); 664