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