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/acpi.h> 62 #include <linux/highmem.h> 63 #include <linux/interrupt.h> 64 #include <linux/io.h> 65 #include <linux/list.h> 66 #include <linux/module.h> 67 #include <linux/platform_device.h> 68 #include <linux/slab.h> 69 #include <linux/spinlock.h> 70 #include <linux/virtio.h> 71 #include <linux/virtio_config.h> 72 #include <linux/virtio_mmio.h> 73 #include <linux/virtio_ring.h> 74 75 76 77 /* The alignment to use between consumer and producer parts of vring. 78 * Currently hardcoded to the page size. */ 79 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE 80 81 82 83 #define to_virtio_mmio_device(_plat_dev) \ 84 container_of(_plat_dev, struct virtio_mmio_device, vdev) 85 86 struct virtio_mmio_device { 87 struct virtio_device vdev; 88 struct platform_device *pdev; 89 90 void __iomem *base; 91 unsigned long version; 92 93 /* a list of queues so we can dispatch IRQs */ 94 spinlock_t lock; 95 struct list_head virtqueues; 96 }; 97 98 struct virtio_mmio_vq_info { 99 /* the actual virtqueue */ 100 struct virtqueue *vq; 101 102 /* the number of entries in the queue */ 103 unsigned int num; 104 105 /* the virtual address of the ring queue */ 106 void *queue; 107 108 /* the list node for the virtqueues list */ 109 struct list_head node; 110 }; 111 112 113 114 /* Configuration interface */ 115 116 static u64 vm_get_features(struct virtio_device *vdev) 117 { 118 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 119 u64 features; 120 121 writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL); 122 features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES); 123 features <<= 32; 124 125 writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL); 126 features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES); 127 128 return features; 129 } 130 131 static int vm_finalize_features(struct virtio_device *vdev) 132 { 133 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 134 135 /* Give virtio_ring a chance to accept features. */ 136 vring_transport_features(vdev); 137 138 /* Make sure there is are no mixed devices */ 139 if (vm_dev->version == 2 && 140 !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) { 141 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n"); 142 return -EINVAL; 143 } 144 145 writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL); 146 writel((u32)(vdev->features >> 32), 147 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES); 148 149 writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL); 150 writel((u32)vdev->features, 151 vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES); 152 153 return 0; 154 } 155 156 static void vm_get(struct virtio_device *vdev, unsigned offset, 157 void *buf, unsigned len) 158 { 159 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 160 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG; 161 u8 b; 162 __le16 w; 163 __le32 l; 164 165 if (vm_dev->version == 1) { 166 u8 *ptr = buf; 167 int i; 168 169 for (i = 0; i < len; i++) 170 ptr[i] = readb(base + offset + i); 171 return; 172 } 173 174 switch (len) { 175 case 1: 176 b = readb(base + offset); 177 memcpy(buf, &b, sizeof b); 178 break; 179 case 2: 180 w = cpu_to_le16(readw(base + offset)); 181 memcpy(buf, &w, sizeof w); 182 break; 183 case 4: 184 l = cpu_to_le32(readl(base + offset)); 185 memcpy(buf, &l, sizeof l); 186 break; 187 case 8: 188 l = cpu_to_le32(readl(base + offset)); 189 memcpy(buf, &l, sizeof l); 190 l = cpu_to_le32(ioread32(base + offset + sizeof l)); 191 memcpy(buf + sizeof l, &l, sizeof l); 192 break; 193 default: 194 BUG(); 195 } 196 } 197 198 static void vm_set(struct virtio_device *vdev, unsigned offset, 199 const void *buf, unsigned len) 200 { 201 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 202 void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG; 203 u8 b; 204 __le16 w; 205 __le32 l; 206 207 if (vm_dev->version == 1) { 208 const u8 *ptr = buf; 209 int i; 210 211 for (i = 0; i < len; i++) 212 writeb(ptr[i], base + offset + i); 213 214 return; 215 } 216 217 switch (len) { 218 case 1: 219 memcpy(&b, buf, sizeof b); 220 writeb(b, base + offset); 221 break; 222 case 2: 223 memcpy(&w, buf, sizeof w); 224 writew(le16_to_cpu(w), base + offset); 225 break; 226 case 4: 227 memcpy(&l, buf, sizeof l); 228 writel(le32_to_cpu(l), base + offset); 229 break; 230 case 8: 231 memcpy(&l, buf, sizeof l); 232 writel(le32_to_cpu(l), base + offset); 233 memcpy(&l, buf + sizeof l, sizeof l); 234 writel(le32_to_cpu(l), base + offset + sizeof l); 235 break; 236 default: 237 BUG(); 238 } 239 } 240 241 static u32 vm_generation(struct virtio_device *vdev) 242 { 243 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 244 245 if (vm_dev->version == 1) 246 return 0; 247 else 248 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION); 249 } 250 251 static u8 vm_get_status(struct virtio_device *vdev) 252 { 253 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 254 255 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff; 256 } 257 258 static void vm_set_status(struct virtio_device *vdev, u8 status) 259 { 260 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 261 262 /* We should never be setting status to 0. */ 263 BUG_ON(status == 0); 264 265 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); 266 } 267 268 static void vm_reset(struct virtio_device *vdev) 269 { 270 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 271 272 /* 0 status means a reset. */ 273 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); 274 } 275 276 277 278 /* Transport interface */ 279 280 /* the notify function used when creating a virt queue */ 281 static bool vm_notify(struct virtqueue *vq) 282 { 283 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 284 285 /* We write the queue's selector into the notification register to 286 * signal the other end */ 287 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); 288 return true; 289 } 290 291 /* Notify all virtqueues on an interrupt. */ 292 static irqreturn_t vm_interrupt(int irq, void *opaque) 293 { 294 struct virtio_mmio_device *vm_dev = opaque; 295 struct virtio_mmio_vq_info *info; 296 unsigned long status; 297 unsigned long flags; 298 irqreturn_t ret = IRQ_NONE; 299 300 /* Read and acknowledge interrupts */ 301 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); 302 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); 303 304 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) { 305 virtio_config_changed(&vm_dev->vdev); 306 ret = IRQ_HANDLED; 307 } 308 309 if (likely(status & VIRTIO_MMIO_INT_VRING)) { 310 spin_lock_irqsave(&vm_dev->lock, flags); 311 list_for_each_entry(info, &vm_dev->virtqueues, node) 312 ret |= vring_interrupt(irq, info->vq); 313 spin_unlock_irqrestore(&vm_dev->lock, flags); 314 } 315 316 return ret; 317 } 318 319 320 321 static void vm_del_vq(struct virtqueue *vq) 322 { 323 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); 324 struct virtio_mmio_vq_info *info = vq->priv; 325 unsigned long flags, size; 326 unsigned int index = vq->index; 327 328 spin_lock_irqsave(&vm_dev->lock, flags); 329 list_del(&info->node); 330 spin_unlock_irqrestore(&vm_dev->lock, flags); 331 332 vring_del_virtqueue(vq); 333 334 /* Select and deactivate the queue */ 335 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 336 if (vm_dev->version == 1) { 337 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 338 } else { 339 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 340 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY)); 341 } 342 343 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); 344 free_pages_exact(info->queue, size); 345 kfree(info); 346 } 347 348 static void vm_del_vqs(struct virtio_device *vdev) 349 { 350 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 351 struct virtqueue *vq, *n; 352 353 list_for_each_entry_safe(vq, n, &vdev->vqs, list) 354 vm_del_vq(vq); 355 356 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev); 357 } 358 359 360 361 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, 362 void (*callback)(struct virtqueue *vq), 363 const char *name) 364 { 365 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 366 struct virtio_mmio_vq_info *info; 367 struct virtqueue *vq; 368 unsigned long flags, size; 369 int err; 370 371 if (!name) 372 return NULL; 373 374 /* Select the queue we're interested in */ 375 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); 376 377 /* Queue shouldn't already be set up. */ 378 if (readl(vm_dev->base + (vm_dev->version == 1 ? 379 VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) { 380 err = -ENOENT; 381 goto error_available; 382 } 383 384 /* Allocate and fill out our active queue description */ 385 info = kmalloc(sizeof(*info), GFP_KERNEL); 386 if (!info) { 387 err = -ENOMEM; 388 goto error_kmalloc; 389 } 390 391 /* Allocate pages for the queue - start with a queue as big as 392 * possible (limited by maximum size allowed by device), drop down 393 * to a minimal size, just big enough to fit descriptor table 394 * and two rings (which makes it "alignment_size * 2") 395 */ 396 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); 397 398 /* If the device reports a 0 entry queue, we won't be able to 399 * use it to perform I/O, and vring_new_virtqueue() can't create 400 * empty queues anyway, so don't bother to set up the device. 401 */ 402 if (info->num == 0) { 403 err = -ENOENT; 404 goto error_alloc_pages; 405 } 406 407 while (1) { 408 size = PAGE_ALIGN(vring_size(info->num, 409 VIRTIO_MMIO_VRING_ALIGN)); 410 /* Did the last iter shrink the queue below minimum size? */ 411 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) { 412 err = -ENOMEM; 413 goto error_alloc_pages; 414 } 415 416 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); 417 if (info->queue) 418 break; 419 420 info->num /= 2; 421 } 422 423 /* Create the vring */ 424 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev, 425 true, info->queue, vm_notify, callback, name); 426 if (!vq) { 427 err = -ENOMEM; 428 goto error_new_virtqueue; 429 } 430 431 /* Activate the queue */ 432 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); 433 if (vm_dev->version == 1) { 434 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); 435 writel(virt_to_phys(info->queue) >> PAGE_SHIFT, 436 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 437 } else { 438 u64 addr; 439 440 addr = virt_to_phys(info->queue); 441 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW); 442 writel((u32)(addr >> 32), 443 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH); 444 445 addr = virt_to_phys(virtqueue_get_avail(vq)); 446 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW); 447 writel((u32)(addr >> 32), 448 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH); 449 450 addr = virt_to_phys(virtqueue_get_used(vq)); 451 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW); 452 writel((u32)(addr >> 32), 453 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH); 454 455 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 456 } 457 458 vq->priv = info; 459 info->vq = vq; 460 461 spin_lock_irqsave(&vm_dev->lock, flags); 462 list_add(&info->node, &vm_dev->virtqueues); 463 spin_unlock_irqrestore(&vm_dev->lock, flags); 464 465 return vq; 466 467 error_new_virtqueue: 468 if (vm_dev->version == 1) { 469 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); 470 } else { 471 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY); 472 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY)); 473 } 474 free_pages_exact(info->queue, size); 475 error_alloc_pages: 476 kfree(info); 477 error_kmalloc: 478 error_available: 479 return ERR_PTR(err); 480 } 481 482 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, 483 struct virtqueue *vqs[], 484 vq_callback_t *callbacks[], 485 const char *names[]) 486 { 487 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 488 unsigned int irq = platform_get_irq(vm_dev->pdev, 0); 489 int i, err; 490 491 err = request_irq(irq, vm_interrupt, IRQF_SHARED, 492 dev_name(&vdev->dev), vm_dev); 493 if (err) 494 return err; 495 496 for (i = 0; i < nvqs; ++i) { 497 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]); 498 if (IS_ERR(vqs[i])) { 499 vm_del_vqs(vdev); 500 return PTR_ERR(vqs[i]); 501 } 502 } 503 504 return 0; 505 } 506 507 static const char *vm_bus_name(struct virtio_device *vdev) 508 { 509 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); 510 511 return vm_dev->pdev->name; 512 } 513 514 static const struct virtio_config_ops virtio_mmio_config_ops = { 515 .get = vm_get, 516 .set = vm_set, 517 .generation = vm_generation, 518 .get_status = vm_get_status, 519 .set_status = vm_set_status, 520 .reset = vm_reset, 521 .find_vqs = vm_find_vqs, 522 .del_vqs = vm_del_vqs, 523 .get_features = vm_get_features, 524 .finalize_features = vm_finalize_features, 525 .bus_name = vm_bus_name, 526 }; 527 528 529 530 /* Platform device */ 531 532 static int virtio_mmio_probe(struct platform_device *pdev) 533 { 534 struct virtio_mmio_device *vm_dev; 535 struct resource *mem; 536 unsigned long magic; 537 538 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); 539 if (!mem) 540 return -EINVAL; 541 542 if (!devm_request_mem_region(&pdev->dev, mem->start, 543 resource_size(mem), pdev->name)) 544 return -EBUSY; 545 546 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); 547 if (!vm_dev) 548 return -ENOMEM; 549 550 vm_dev->vdev.dev.parent = &pdev->dev; 551 vm_dev->vdev.config = &virtio_mmio_config_ops; 552 vm_dev->pdev = pdev; 553 INIT_LIST_HEAD(&vm_dev->virtqueues); 554 spin_lock_init(&vm_dev->lock); 555 556 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); 557 if (vm_dev->base == NULL) 558 return -EFAULT; 559 560 /* Check magic value */ 561 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); 562 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) { 563 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); 564 return -ENODEV; 565 } 566 567 /* Check device version */ 568 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); 569 if (vm_dev->version < 1 || vm_dev->version > 2) { 570 dev_err(&pdev->dev, "Version %ld not supported!\n", 571 vm_dev->version); 572 return -ENXIO; 573 } 574 575 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); 576 if (vm_dev->vdev.id.device == 0) { 577 /* 578 * virtio-mmio device with an ID 0 is a (dummy) placeholder 579 * with no function. End probing now with no error reported. 580 */ 581 return -ENODEV; 582 } 583 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); 584 585 if (vm_dev->version == 1) 586 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); 587 588 platform_set_drvdata(pdev, vm_dev); 589 590 return register_virtio_device(&vm_dev->vdev); 591 } 592 593 static int virtio_mmio_remove(struct platform_device *pdev) 594 { 595 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); 596 597 unregister_virtio_device(&vm_dev->vdev); 598 599 return 0; 600 } 601 602 603 604 /* Devices list parameter */ 605 606 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES) 607 608 static struct device vm_cmdline_parent = { 609 .init_name = "virtio-mmio-cmdline", 610 }; 611 612 static int vm_cmdline_parent_registered; 613 static int vm_cmdline_id; 614 615 static int vm_cmdline_set(const char *device, 616 const struct kernel_param *kp) 617 { 618 int err; 619 struct resource resources[2] = {}; 620 char *str; 621 long long int base, size; 622 unsigned int irq; 623 int processed, consumed = 0; 624 struct platform_device *pdev; 625 626 /* Consume "size" part of the command line parameter */ 627 size = memparse(device, &str); 628 629 /* Get "@<base>:<irq>[:<id>]" chunks */ 630 processed = sscanf(str, "@%lli:%u%n:%d%n", 631 &base, &irq, &consumed, 632 &vm_cmdline_id, &consumed); 633 634 /* 635 * sscanf() must processes at least 2 chunks; also there 636 * must be no extra characters after the last chunk, so 637 * str[consumed] must be '\0' 638 */ 639 if (processed < 2 || str[consumed]) 640 return -EINVAL; 641 642 resources[0].flags = IORESOURCE_MEM; 643 resources[0].start = base; 644 resources[0].end = base + size - 1; 645 646 resources[1].flags = IORESOURCE_IRQ; 647 resources[1].start = resources[1].end = irq; 648 649 if (!vm_cmdline_parent_registered) { 650 err = device_register(&vm_cmdline_parent); 651 if (err) { 652 pr_err("Failed to register parent device!\n"); 653 return err; 654 } 655 vm_cmdline_parent_registered = 1; 656 } 657 658 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n", 659 vm_cmdline_id, 660 (unsigned long long)resources[0].start, 661 (unsigned long long)resources[0].end, 662 (int)resources[1].start); 663 664 pdev = platform_device_register_resndata(&vm_cmdline_parent, 665 "virtio-mmio", vm_cmdline_id++, 666 resources, ARRAY_SIZE(resources), NULL, 0); 667 if (IS_ERR(pdev)) 668 return PTR_ERR(pdev); 669 670 return 0; 671 } 672 673 static int vm_cmdline_get_device(struct device *dev, void *data) 674 { 675 char *buffer = data; 676 unsigned int len = strlen(buffer); 677 struct platform_device *pdev = to_platform_device(dev); 678 679 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n", 680 pdev->resource[0].end - pdev->resource[0].start + 1ULL, 681 (unsigned long long)pdev->resource[0].start, 682 (unsigned long long)pdev->resource[1].start, 683 pdev->id); 684 return 0; 685 } 686 687 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp) 688 { 689 buffer[0] = '\0'; 690 device_for_each_child(&vm_cmdline_parent, buffer, 691 vm_cmdline_get_device); 692 return strlen(buffer) + 1; 693 } 694 695 static const struct kernel_param_ops vm_cmdline_param_ops = { 696 .set = vm_cmdline_set, 697 .get = vm_cmdline_get, 698 }; 699 700 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR); 701 702 static int vm_unregister_cmdline_device(struct device *dev, 703 void *data) 704 { 705 platform_device_unregister(to_platform_device(dev)); 706 707 return 0; 708 } 709 710 static void vm_unregister_cmdline_devices(void) 711 { 712 if (vm_cmdline_parent_registered) { 713 device_for_each_child(&vm_cmdline_parent, NULL, 714 vm_unregister_cmdline_device); 715 device_unregister(&vm_cmdline_parent); 716 vm_cmdline_parent_registered = 0; 717 } 718 } 719 720 #else 721 722 static void vm_unregister_cmdline_devices(void) 723 { 724 } 725 726 #endif 727 728 /* Platform driver */ 729 730 static struct of_device_id virtio_mmio_match[] = { 731 { .compatible = "virtio,mmio", }, 732 {}, 733 }; 734 MODULE_DEVICE_TABLE(of, virtio_mmio_match); 735 736 #ifdef CONFIG_ACPI 737 static const struct acpi_device_id virtio_mmio_acpi_match[] = { 738 { "LNRO0005", }, 739 { } 740 }; 741 MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match); 742 #endif 743 744 static struct platform_driver virtio_mmio_driver = { 745 .probe = virtio_mmio_probe, 746 .remove = virtio_mmio_remove, 747 .driver = { 748 .name = "virtio-mmio", 749 .of_match_table = virtio_mmio_match, 750 .acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match), 751 }, 752 }; 753 754 static int __init virtio_mmio_init(void) 755 { 756 return platform_driver_register(&virtio_mmio_driver); 757 } 758 759 static void __exit virtio_mmio_exit(void) 760 { 761 platform_driver_unregister(&virtio_mmio_driver); 762 vm_unregister_cmdline_devices(); 763 } 764 765 module_init(virtio_mmio_init); 766 module_exit(virtio_mmio_exit); 767 768 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>"); 769 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices"); 770 MODULE_LICENSE("GPL"); 771