1 /* 2 * Virtio memory mapped device driver 3 * 4 * Copyright 2011-2014, 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 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007 54 * 55 * This work is licensed under the terms of the GNU GPL, version 2 or later. 56 * See the COPYING file in the top-level directory. 57 */ 58 59 #define pr_fmt(fmt) "virtio-mmio: " fmt 60 61 #include <linux/highmem.h> 62 #include <linux/interrupt.h> 63 #include <linux/io.h> 64 #include <linux/list.h> 65 #include <linux/module.h> 66 #include <linux/platform_device.h> 67 #include <linux/slab.h> 68 #include <linux/spinlock.h> 69 #include <linux/virtio.h> 70 #include <linux/virtio_config.h> 71 #include <linux/virtio_mmio.h> 72 #include <linux/virtio_ring.h> 73 74 75 76 /* The alignment to use between consumer and producer parts of vring. 77 * Currently hardcoded to the page size. */ 78 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE 79 80 81 82 #define to_virtio_mmio_device(_plat_dev) \ 83 container_of(_plat_dev, struct virtio_mmio_device, vdev) 84 85 struct virtio_mmio_device { 86 struct virtio_device vdev; 87 struct platform_device *pdev; 88 89 void __iomem *base; 90 unsigned long version; 91 92 /* a list of queues so we can dispatch IRQs */ 93 spinlock_t lock; 94 struct list_head virtqueues; 95 }; 96 97 struct virtio_mmio_vq_info { 98 /* the actual virtqueue */ 99 struct virtqueue *vq; 100 101 /* the number of entries in the queue */ 102 unsigned int num; 103 104 /* the virtual address of the ring queue */ 105 void *queue; 106 107 /* the list node for the virtqueues list */ 108 struct list_head node; 109 }; 110 111 112 113 /* Configuration interface */ 114 115 static u64 vm_get_features(struct virtio_device *vdev) 116 { 117 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 118 u64 features; 119 120 writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL); 121 features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES); 122 features <<= 32; 123 124 writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL); 125 features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES); 126 127 return features; 128 } 129 130 static int vm_finalize_features(struct virtio_device *vdev) 131 { 132 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 133 134 /* Give virtio_ring a chance to accept features. */ 135 vring_transport_features(vdev); 136 137 /* Make sure there is are no mixed devices */ 138 if (vm_dev->version == 2 && 139 !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) { 140 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n"); 141 return -EINVAL; 142 } 143 144 writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL); 145 writel((u32)(vdev->features >> 32), 146 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES); 147 148 writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL); 149 writel((u32)vdev->features, 150 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES); 151 152 return 0; 153 } 154 155 static void vm_get(struct virtio_device *vdev, unsigned offset, 156 void *buf, unsigned len) 157 { 158 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 159 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG; 160 u8 b; 161 __le16 w; 162 __le32 l; 163 164 if (vm_dev->version == 1) { 165 u8 *ptr = buf; 166 int i; 167 168 for (i = 0; i < len; i++) 169 ptr[i] = readb(base + offset + i); 170 return; 171 } 172 173 switch (len) { 174 case 1: 175 b = readb(base + offset); 176 memcpy(buf, &b, sizeof b); 177 break; 178 case 2: 179 w = cpu_to_le16(readw(base + offset)); 180 memcpy(buf, &w, sizeof w); 181 break; 182 case 4: 183 l = cpu_to_le32(readl(base + offset)); 184 memcpy(buf, &l, sizeof l); 185 break; 186 case 8: 187 l = cpu_to_le32(readl(base + offset)); 188 memcpy(buf, &l, sizeof l); 189 l = cpu_to_le32(ioread32(base + offset + sizeof l)); 190 memcpy(buf + sizeof l, &l, sizeof l); 191 break; 192 default: 193 BUG(); 194 } 195 } 196 197 static void vm_set(struct virtio_device *vdev, unsigned offset, 198 const void *buf, unsigned len) 199 { 200 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 201 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG; 202 u8 b; 203 __le16 w; 204 __le32 l; 205 206 if (vm_dev->version == 1) { 207 const u8 *ptr = buf; 208 int i; 209 210 for (i = 0; i < len; i++) 211 writeb(ptr[i], base + offset + i); 212 213 return; 214 } 215 216 switch (len) { 217 case 1: 218 memcpy(&b, buf, sizeof b); 219 writeb(b, base + offset); 220 break; 221 case 2: 222 memcpy(&w, buf, sizeof w); 223 writew(le16_to_cpu(w), base + offset); 224 break; 225 case 4: 226 memcpy(&l, buf, sizeof l); 227 writel(le32_to_cpu(l), base + offset); 228 break; 229 case 8: 230 memcpy(&l, buf, sizeof l); 231 writel(le32_to_cpu(l), base + offset); 232 memcpy(&l, buf + sizeof l, sizeof l); 233 writel(le32_to_cpu(l), base + offset + sizeof l); 234 break; 235 default: 236 BUG(); 237 } 238 } 239 240 static u32 vm_generation(struct virtio_device *vdev) 241 { 242 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 243 244 if (vm_dev->version == 1) 245 return 0; 246 else 247 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION); 248 } 249 250 static u8 vm_get_status(struct virtio_device *vdev) 251 { 252 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 253 254 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff; 255 } 256 257 static void vm_set_status(struct virtio_device *vdev, u8 status) 258 { 259 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 260 261 /* We should never be setting status to 0. */ 262 BUG_ON(status == 0); 263 264 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); 265 } 266 267 static void vm_reset(struct virtio_device *vdev) 268 { 269 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 270 271 /* 0 status means a reset. */ 272 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); 273 } 274 275 276 277 /* Transport interface */ 278 279 /* the notify function used when creating a virt queue */ 280 static bool vm_notify(struct virtqueue *vq) 281 { 282 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 283 284 /* We write the queue's selector into the notification register to 285 * signal the other end */ 286 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); 287 return true; 288 } 289 290 /* Notify all virtqueues on an interrupt. */ 291 static irqreturn_t vm_interrupt(int irq, void *opaque) 292 { 293 struct virtio_mmio_device *vm_dev = opaque; 294 struct virtio_mmio_vq_info *info; 295 unsigned long status; 296 unsigned long flags; 297 irqreturn_t ret = IRQ_NONE; 298 299 /* Read and acknowledge interrupts */ 300 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); 301 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); 302 303 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) { 304 virtio_config_changed(&vm_dev->vdev); 305 ret = IRQ_HANDLED; 306 } 307 308 if (likely(status & VIRTIO_MMIO_INT_VRING)) { 309 spin_lock_irqsave(&vm_dev->lock, flags); 310 list_for_each_entry(info, &vm_dev->virtqueues, node) 311 ret |= vring_interrupt(irq, info->vq); 312 spin_unlock_irqrestore(&vm_dev->lock, flags); 313 } 314 315 return ret; 316 } 317 318 319 320 static void vm_del_vq(struct virtqueue *vq) 321 { 322 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 323 struct virtio_mmio_vq_info *info = vq->priv; 324 unsigned long flags, size; 325 unsigned int index = vq->index; 326 327 spin_lock_irqsave(&vm_dev->lock, flags); 328 list_del(&info->node); 329 spin_unlock_irqrestore(&vm_dev->lock, flags); 330 331 vring_del_virtqueue(vq); 332 333 /* Select and deactivate the queue */ 334 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 335 if (vm_dev->version == 1) { 336 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 337 } else { 338 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 339 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY)); 340 } 341 342 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); 343 free_pages_exact(info->queue, size); 344 kfree(info); 345 } 346 347 static void vm_del_vqs(struct virtio_device *vdev) 348 { 349 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 350 struct virtqueue *vq, *n; 351 352 list_for_each_entry_safe(vq, n, &vdev->vqs, list) 353 vm_del_vq(vq); 354 355 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev); 356 } 357 358 359 360 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, 361 void (*callback)(struct virtqueue *vq), 362 const char *name) 363 { 364 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 365 struct virtio_mmio_vq_info *info; 366 struct virtqueue *vq; 367 unsigned long flags, size; 368 int err; 369 370 if (!name) 371 return NULL; 372 373 /* Select the queue we're interested in */ 374 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 375 376 /* Queue shouldn't already be set up. */ 377 if (readl(vm_dev->base + (vm_dev->version == 1 ? 378 VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) { 379 err = -ENOENT; 380 goto error_available; 381 } 382 383 /* Allocate and fill out our active queue description */ 384 info = kmalloc(sizeof(*info), GFP_KERNEL); 385 if (!info) { 386 err = -ENOMEM; 387 goto error_kmalloc; 388 } 389 390 /* Allocate pages for the queue - start with a queue as big as 391 * possible (limited by maximum size allowed by device), drop down 392 * to a minimal size, just big enough to fit descriptor table 393 * and two rings (which makes it "alignment_size * 2") 394 */ 395 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); 396 397 /* If the device reports a 0 entry queue, we won't be able to 398 * use it to perform I/O, and vring_new_virtqueue() can't create 399 * empty queues anyway, so don't bother to set up the device. 400 */ 401 if (info->num == 0) { 402 err = -ENOENT; 403 goto error_alloc_pages; 404 } 405 406 while (1) { 407 size = PAGE_ALIGN(vring_size(info->num, 408 VIRTIO_MMIO_VRING_ALIGN)); 409 /* Did the last iter shrink the queue below minimum size? */ 410 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) { 411 err = -ENOMEM; 412 goto error_alloc_pages; 413 } 414 415 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); 416 if (info->queue) 417 break; 418 419 info->num /= 2; 420 } 421 422 /* Create the vring */ 423 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev, 424 true, info->queue, vm_notify, callback, name); 425 if (!vq) { 426 err = -ENOMEM; 427 goto error_new_virtqueue; 428 } 429 430 /* Activate the queue */ 431 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); 432 if (vm_dev->version == 1) { 433 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); 434 writel(virt_to_phys(info->queue) >> PAGE_SHIFT, 435 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 436 } else { 437 u64 addr; 438 439 addr = virt_to_phys(info->queue); 440 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW); 441 writel((u32)(addr >> 32), 442 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH); 443 444 addr = virt_to_phys(virtqueue_get_avail(vq)); 445 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW); 446 writel((u32)(addr >> 32), 447 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH); 448 449 addr = virt_to_phys(virtqueue_get_used(vq)); 450 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW); 451 writel((u32)(addr >> 32), 452 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH); 453 454 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 455 } 456 457 vq->priv = info; 458 info->vq = vq; 459 460 spin_lock_irqsave(&vm_dev->lock, flags); 461 list_add(&info->node, &vm_dev->virtqueues); 462 spin_unlock_irqrestore(&vm_dev->lock, flags); 463 464 return vq; 465 466 error_new_virtqueue: 467 if (vm_dev->version == 1) { 468 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 469 } else { 470 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 471 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY)); 472 } 473 free_pages_exact(info->queue, size); 474 error_alloc_pages: 475 kfree(info); 476 error_kmalloc: 477 error_available: 478 return ERR_PTR(err); 479 } 480 481 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, 482 struct virtqueue *vqs[], 483 vq_callback_t *callbacks[], 484 const char *names[]) 485 { 486 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 487 unsigned int irq = platform_get_irq(vm_dev->pdev, 0); 488 int i, err; 489 490 err = request_irq(irq, vm_interrupt, IRQF_SHARED, 491 dev_name(&vdev->dev), vm_dev); 492 if (err) 493 return err; 494 495 for (i = 0; i < nvqs; ++i) { 496 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]); 497 if (IS_ERR(vqs[i])) { 498 vm_del_vqs(vdev); 499 return PTR_ERR(vqs[i]); 500 } 501 } 502 503 return 0; 504 } 505 506 static const char *vm_bus_name(struct virtio_device *vdev) 507 { 508 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 509 510 return vm_dev->pdev->name; 511 } 512 513 static const struct virtio_config_ops virtio_mmio_config_ops = { 514 .get = vm_get, 515 .set = vm_set, 516 .generation = vm_generation, 517 .get_status = vm_get_status, 518 .set_status = vm_set_status, 519 .reset = vm_reset, 520 .find_vqs = vm_find_vqs, 521 .del_vqs = vm_del_vqs, 522 .get_features = vm_get_features, 523 .finalize_features = vm_finalize_features, 524 .bus_name = vm_bus_name, 525 }; 526 527 528 529 /* Platform device */ 530 531 static int virtio_mmio_probe(struct platform_device *pdev) 532 { 533 struct virtio_mmio_device *vm_dev; 534 struct resource *mem; 535 unsigned long magic; 536 537 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 538 if (!mem) 539 return -EINVAL; 540 541 if (!devm_request_mem_region(&pdev->dev, mem->start, 542 resource_size(mem), pdev->name)) 543 return -EBUSY; 544 545 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); 546 if (!vm_dev) 547 return -ENOMEM; 548 549 vm_dev->vdev.dev.parent = &pdev->dev; 550 vm_dev->vdev.config = &virtio_mmio_config_ops; 551 vm_dev->pdev = pdev; 552 INIT_LIST_HEAD(&vm_dev->virtqueues); 553 spin_lock_init(&vm_dev->lock); 554 555 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); 556 if (vm_dev->base == NULL) 557 return -EFAULT; 558 559 /* Check magic value */ 560 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); 561 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) { 562 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); 563 return -ENODEV; 564 } 565 566 /* Check device version */ 567 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); 568 if (vm_dev->version < 1 || vm_dev->version > 2) { 569 dev_err(&pdev->dev, "Version %ld not supported!\n", 570 vm_dev->version); 571 return -ENXIO; 572 } 573 574 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); 575 if (vm_dev->vdev.id.device == 0) { 576 /* 577 * virtio-mmio device with an ID 0 is a (dummy) placeholder 578 * with no function. End probing now with no error reported. 579 */ 580 return -ENODEV; 581 } 582 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); 583 584 if (vm_dev->version == 1) 585 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); 586 587 platform_set_drvdata(pdev, vm_dev); 588 589 return register_virtio_device(&vm_dev->vdev); 590 } 591 592 static int virtio_mmio_remove(struct platform_device *pdev) 593 { 594 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); 595 596 unregister_virtio_device(&vm_dev->vdev); 597 598 return 0; 599 } 600 601 602 603 /* Devices list parameter */ 604 605 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES) 606 607 static struct device vm_cmdline_parent = { 608 .init_name = "virtio-mmio-cmdline", 609 }; 610 611 static int vm_cmdline_parent_registered; 612 static int vm_cmdline_id; 613 614 static int vm_cmdline_set(const char *device, 615 const struct kernel_param *kp) 616 { 617 int err; 618 struct resource resources[2] = {}; 619 char *str; 620 long long int base, size; 621 unsigned int irq; 622 int processed, consumed = 0; 623 struct platform_device *pdev; 624 625 /* Consume "size" part of the command line parameter */ 626 size = memparse(device, &str); 627 628 /* Get "@<base>:<irq>[:<id>]" chunks */ 629 processed = sscanf(str, "@%lli:%u%n:%d%n", 630 &base, &irq, &consumed, 631 &vm_cmdline_id, &consumed); 632 633 /* 634 * sscanf() must processes at least 2 chunks; also there 635 * must be no extra characters after the last chunk, so 636 * str[consumed] must be '\0' 637 */ 638 if (processed < 2 || str[consumed]) 639 return -EINVAL; 640 641 resources[0].flags = IORESOURCE_MEM; 642 resources[0].start = base; 643 resources[0].end = base + size - 1; 644 645 resources[1].flags = IORESOURCE_IRQ; 646 resources[1].start = resources[1].end = irq; 647 648 if (!vm_cmdline_parent_registered) { 649 err = device_register(&vm_cmdline_parent); 650 if (err) { 651 pr_err("Failed to register parent device!\n"); 652 return err; 653 } 654 vm_cmdline_parent_registered = 1; 655 } 656 657 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n", 658 vm_cmdline_id, 659 (unsigned long long)resources[0].start, 660 (unsigned long long)resources[0].end, 661 (int)resources[1].start); 662 663 pdev = platform_device_register_resndata(&vm_cmdline_parent, 664 "virtio-mmio", vm_cmdline_id++, 665 resources, ARRAY_SIZE(resources), NULL, 0); 666 if (IS_ERR(pdev)) 667 return PTR_ERR(pdev); 668 669 return 0; 670 } 671 672 static int vm_cmdline_get_device(struct device *dev, void *data) 673 { 674 char *buffer = data; 675 unsigned int len = strlen(buffer); 676 struct platform_device *pdev = to_platform_device(dev); 677 678 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n", 679 pdev->resource[0].end - pdev->resource[0].start + 1ULL, 680 (unsigned long long)pdev->resource[0].start, 681 (unsigned long long)pdev->resource[1].start, 682 pdev->id); 683 return 0; 684 } 685 686 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp) 687 { 688 buffer[0] = '\0'; 689 device_for_each_child(&vm_cmdline_parent, buffer, 690 vm_cmdline_get_device); 691 return strlen(buffer) + 1; 692 } 693 694 static const struct kernel_param_ops vm_cmdline_param_ops = { 695 .set = vm_cmdline_set, 696 .get = vm_cmdline_get, 697 }; 698 699 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR); 700 701 static int vm_unregister_cmdline_device(struct device *dev, 702 void *data) 703 { 704 platform_device_unregister(to_platform_device(dev)); 705 706 return 0; 707 } 708 709 static void vm_unregister_cmdline_devices(void) 710 { 711 if (vm_cmdline_parent_registered) { 712 device_for_each_child(&vm_cmdline_parent, NULL, 713 vm_unregister_cmdline_device); 714 device_unregister(&vm_cmdline_parent); 715 vm_cmdline_parent_registered = 0; 716 } 717 } 718 719 #else 720 721 static void vm_unregister_cmdline_devices(void) 722 { 723 } 724 725 #endif 726 727 /* Platform driver */ 728 729 static struct of_device_id virtio_mmio_match[] = { 730 { .compatible = "virtio,mmio", }, 731 {}, 732 }; 733 MODULE_DEVICE_TABLE(of, virtio_mmio_match); 734 735 static struct platform_driver virtio_mmio_driver = { 736 .probe = virtio_mmio_probe, 737 .remove = virtio_mmio_remove, 738 .driver = { 739 .name = "virtio-mmio", 740 .of_match_table = virtio_mmio_match, 741 }, 742 }; 743 744 static int __init virtio_mmio_init(void) 745 { 746 return platform_driver_register(&virtio_mmio_driver); 747 } 748 749 static void __exit virtio_mmio_exit(void) 750 { 751 platform_driver_unregister(&virtio_mmio_driver); 752 vm_unregister_cmdline_devices(); 753 } 754 755 module_init(virtio_mmio_init); 756 module_exit(virtio_mmio_exit); 757 758 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>"); 759 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices"); 760 MODULE_LICENSE("GPL"); 761