root/drivers/virtio/virtio_mmio.c

DEFINITIONS

1. vm_get_features
2. vm_finalize_features
3. vm_get
4. vm_set
5. vm_generation
6. vm_get_status
7. vm_set_status
8. vm_reset
9. vm_notify
10. vm_interrupt
11. vm_del_vq
12. vm_del_vqs
13. vm_setup_vq
14. vm_find_vqs
15. vm_bus_name
16. virtio_mmio_release_dev
17. virtio_mmio_probe
18. virtio_mmio_remove
19. vm_cmdline_set
20. vm_cmdline_get_device
21. vm_cmdline_get
22. vm_unregister_cmdline_device
23. vm_unregister_cmdline_devices
24. vm_unregister_cmdline_devices
25. virtio_mmio_init
26. virtio_mmio_exit

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Virtio memory mapped device driver
   4  *
   5  * Copyright 2011-2014, ARM Ltd.
   6  *
   7  * This module allows virtio devices to be used over a virtual, memory mapped
   8  * platform device.
   9  *
  10  * The guest device(s) may be instantiated in one of three equivalent ways:
  11  *
  12  * 1. Static platform device in board's code, eg.:
  13  *
  14  *      static struct platform_device v2m_virtio_device = {
  15  *              .name = "virtio-mmio",
  16  *              .id = -1,
  17  *              .num_resources = 2,
  18  *              .resource = (struct resource []) {
  19  *                      {
  20  *                              .start = 0x1001e000,
  21  *                              .end = 0x1001e0ff,
  22  *                              .flags = IORESOURCE_MEM,
  23  *                      }, {
  24  *                              .start = 42 + 32,
  25  *                              .end = 42 + 32,
  26  *                              .flags = IORESOURCE_IRQ,
  27  *                      },
  28  *              }
  29  *      };
  30  *
  31  * 2. Device Tree node, eg.:
  32  *
  33  *              virtio_block@1e000 {
  34  *                      compatible = "virtio,mmio";
  35  *                      reg = <0x1e000 0x100>;
  36  *                      interrupts = <42>;
  37  *              }
  38  *
  39  * 3. Kernel module (or command line) parameter. Can be used more than once -
  40  *    one device will be created for each one. Syntax:
  41  *
  42  *              [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
  43  *    where:
  44  *              <size>     := size (can use standard suffixes like K, M or G)
  45  *              <baseaddr> := physical base address
  46  *              <irq>      := interrupt number (as passed to request_irq())
  47  *              <id>       := (optional) platform device id
  48  *    eg.:
  49  *              virtio_mmio.device=0x100@0x100b0000:48 \
  50  *                              virtio_mmio.device=1K@0x1001e000:74
  51  *
  52  * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
  53  */
  54 
  55 #define pr_fmt(fmt) "virtio-mmio: " fmt
  56 
  57 #include <linux/acpi.h>
  58 #include <linux/dma-mapping.h>
  59 #include <linux/highmem.h>
  60 #include <linux/interrupt.h>
  61 #include <linux/io.h>
  62 #include <linux/list.h>
  63 #include <linux/module.h>
  64 #include <linux/platform_device.h>
  65 #include <linux/slab.h>
  66 #include <linux/spinlock.h>
  67 #include <linux/virtio.h>
  68 #include <linux/virtio_config.h>
  69 #include <uapi/linux/virtio_mmio.h>
  70 #include <linux/virtio_ring.h>
  71 
  72 
  73 
  74 /* The alignment to use between consumer and producer parts of vring.
  75  * Currently hardcoded to the page size. */
  76 #define VIRTIO_MMIO_VRING_ALIGN         PAGE_SIZE
  77 
  78 
  79 
  80 #define to_virtio_mmio_device(_plat_dev) \
  81         container_of(_plat_dev, struct virtio_mmio_device, vdev)
  82 
  83 struct virtio_mmio_device {
  84         struct virtio_device vdev;
  85         struct platform_device *pdev;
  86 
  87         void __iomem *base;
  88         unsigned long version;
  89 
  90         /* a list of queues so we can dispatch IRQs */
  91         spinlock_t lock;
  92         struct list_head virtqueues;
  93 };
  94 
  95 struct virtio_mmio_vq_info {
  96         /* the actual virtqueue */
  97         struct virtqueue *vq;
  98 
  99         /* the list node for the virtqueues list */
 100         struct list_head node;
 101 };
 102 
 103 
 104 
 105 /* Configuration interface */
 106 
 107 static u64 vm_get_features(struct virtio_device *vdev)
 108 {
 109         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 110         u64 features;
 111 
 112         writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
 113         features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
 114         features <<= 32;
 115 
 116         writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
 117         features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
 118 
 119         return features;
 120 }
 121 
 122 static int vm_finalize_features(struct virtio_device *vdev)
 123 {
 124         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 125 
 126         /* Give virtio_ring a chance to accept features. */
 127         vring_transport_features(vdev);
 128 
 129         /* Make sure there is are no mixed devices */
 130         if (vm_dev->version == 2 &&
 131                         !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
 132                 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
 133                 return -EINVAL;
 134         }
 135 
 136         writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
 137         writel((u32)(vdev->features >> 32),
 138                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
 139 
 140         writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
 141         writel((u32)vdev->features,
 142                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
 143 
 144         return 0;
 145 }
 146 
 147 static void vm_get(struct virtio_device *vdev, unsigned offset,
 148                    void *buf, unsigned len)
 149 {
 150         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 151         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
 152         u8 b;
 153         __le16 w;
 154         __le32 l;
 155 
 156         if (vm_dev->version == 1) {
 157                 u8 *ptr = buf;
 158                 int i;
 159 
 160                 for (i = 0; i < len; i++)
 161                         ptr[i] = readb(base + offset + i);
 162                 return;
 163         }
 164 
 165         switch (len) {
 166         case 1:
 167                 b = readb(base + offset);
 168                 memcpy(buf, &b, sizeof b);
 169                 break;
 170         case 2:
 171                 w = cpu_to_le16(readw(base + offset));
 172                 memcpy(buf, &w, sizeof w);
 173                 break;
 174         case 4:
 175                 l = cpu_to_le32(readl(base + offset));
 176                 memcpy(buf, &l, sizeof l);
 177                 break;
 178         case 8:
 179                 l = cpu_to_le32(readl(base + offset));
 180                 memcpy(buf, &l, sizeof l);
 181                 l = cpu_to_le32(ioread32(base + offset + sizeof l));
 182                 memcpy(buf + sizeof l, &l, sizeof l);
 183                 break;
 184         default:
 185                 BUG();
 186         }
 187 }
 188 
 189 static void vm_set(struct virtio_device *vdev, unsigned offset,
 190                    const void *buf, unsigned len)
 191 {
 192         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 193         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
 194         u8 b;
 195         __le16 w;
 196         __le32 l;
 197 
 198         if (vm_dev->version == 1) {
 199                 const u8 *ptr = buf;
 200                 int i;
 201 
 202                 for (i = 0; i < len; i++)
 203                         writeb(ptr[i], base + offset + i);
 204 
 205                 return;
 206         }
 207 
 208         switch (len) {
 209         case 1:
 210                 memcpy(&b, buf, sizeof b);
 211                 writeb(b, base + offset);
 212                 break;
 213         case 2:
 214                 memcpy(&w, buf, sizeof w);
 215                 writew(le16_to_cpu(w), base + offset);
 216                 break;
 217         case 4:
 218                 memcpy(&l, buf, sizeof l);
 219                 writel(le32_to_cpu(l), base + offset);
 220                 break;
 221         case 8:
 222                 memcpy(&l, buf, sizeof l);
 223                 writel(le32_to_cpu(l), base + offset);
 224                 memcpy(&l, buf + sizeof l, sizeof l);
 225                 writel(le32_to_cpu(l), base + offset + sizeof l);
 226                 break;
 227         default:
 228                 BUG();
 229         }
 230 }
 231 
 232 static u32 vm_generation(struct virtio_device *vdev)
 233 {
 234         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 235 
 236         if (vm_dev->version == 1)
 237                 return 0;
 238         else
 239                 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
 240 }
 241 
 242 static u8 vm_get_status(struct virtio_device *vdev)
 243 {
 244         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 245 
 246         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
 247 }
 248 
 249 static void vm_set_status(struct virtio_device *vdev, u8 status)
 250 {
 251         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 252 
 253         /* We should never be setting status to 0. */
 254         BUG_ON(status == 0);
 255 
 256         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
 257 }
 258 
 259 static void vm_reset(struct virtio_device *vdev)
 260 {
 261         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 262 
 263         /* 0 status means a reset. */
 264         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
 265 }
 266 
 267 
 268 
 269 /* Transport interface */
 270 
 271 /* the notify function used when creating a virt queue */
 272 static bool vm_notify(struct virtqueue *vq)
 273 {
 274         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 275 
 276         /* We write the queue's selector into the notification register to
 277          * signal the other end */
 278         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
 279         return true;
 280 }
 281 
 282 /* Notify all virtqueues on an interrupt. */
 283 static irqreturn_t vm_interrupt(int irq, void *opaque)
 284 {
 285         struct virtio_mmio_device *vm_dev = opaque;
 286         struct virtio_mmio_vq_info *info;
 287         unsigned long status;
 288         unsigned long flags;
 289         irqreturn_t ret = IRQ_NONE;
 290 
 291         /* Read and acknowledge interrupts */
 292         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
 293         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
 294 
 295         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
 296                 virtio_config_changed(&vm_dev->vdev);
 297                 ret = IRQ_HANDLED;
 298         }
 299 
 300         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
 301                 spin_lock_irqsave(&vm_dev->lock, flags);
 302                 list_for_each_entry(info, &vm_dev->virtqueues, node)
 303                         ret |= vring_interrupt(irq, info->vq);
 304                 spin_unlock_irqrestore(&vm_dev->lock, flags);
 305         }
 306 
 307         return ret;
 308 }
 309 
 310 
 311 
 312 static void vm_del_vq(struct virtqueue *vq)
 313 {
 314         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
 315         struct virtio_mmio_vq_info *info = vq->priv;
 316         unsigned long flags;
 317         unsigned int index = vq->index;
 318 
 319         spin_lock_irqsave(&vm_dev->lock, flags);
 320         list_del(&info->node);
 321         spin_unlock_irqrestore(&vm_dev->lock, flags);
 322 
 323         /* Select and deactivate the queue */
 324         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 325         if (vm_dev->version == 1) {
 326                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 327         } else {
 328                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
 329                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
 330         }
 331 
 332         vring_del_virtqueue(vq);
 333 
 334         kfree(info);
 335 }
 336 
 337 static void vm_del_vqs(struct virtio_device *vdev)
 338 {
 339         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 340         struct virtqueue *vq, *n;
 341 
 342         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 343                 vm_del_vq(vq);
 344 
 345         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
 346 }
 347 
 348 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
 349                                   void (*callback)(struct virtqueue *vq),
 350                                   const char *name, bool ctx)
 351 {
 352         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 353         struct virtio_mmio_vq_info *info;
 354         struct virtqueue *vq;
 355         unsigned long flags;
 356         unsigned int num;
 357         int err;
 358 
 359         if (!name)
 360                 return NULL;
 361 
 362         /* Select the queue we're interested in */
 363         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
 364 
 365         /* Queue shouldn't already be set up. */
 366         if (readl(vm_dev->base + (vm_dev->version == 1 ?
 367                         VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
 368                 err = -ENOENT;
 369                 goto error_available;
 370         }
 371 
 372         /* Allocate and fill out our active queue description */
 373         info = kmalloc(sizeof(*info), GFP_KERNEL);
 374         if (!info) {
 375                 err = -ENOMEM;
 376                 goto error_kmalloc;
 377         }
 378 
 379         num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
 380         if (num == 0) {
 381                 err = -ENOENT;
 382                 goto error_new_virtqueue;
 383         }
 384 
 385         /* Create the vring */
 386         vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
 387                                  true, true, ctx, vm_notify, callback, name);
 388         if (!vq) {
 389                 err = -ENOMEM;
 390                 goto error_new_virtqueue;
 391         }
 392 
 393         /* Activate the queue */
 394         writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 395         if (vm_dev->version == 1) {
 396                 u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT;
 397 
 398                 /*
 399                  * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
 400                  * that doesn't fit in 32bit, fail the setup rather than
 401                  * pretending to be successful.
 402                  */
 403                 if (q_pfn >> 32) {
 404                         dev_err(&vdev->dev,
 405                                 "platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
 406                                 0x1ULL << (32 + PAGE_SHIFT - 30));
 407                         err = -E2BIG;
 408                         goto error_bad_pfn;
 409                 }
 410 
 411                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
 412                 writel(q_pfn, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 413         } else {
 414                 u64 addr;
 415 
 416                 addr = virtqueue_get_desc_addr(vq);
 417                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
 418                 writel((u32)(addr >> 32),
 419                                 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
 420 
 421                 addr = virtqueue_get_avail_addr(vq);
 422                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
 423                 writel((u32)(addr >> 32),
 424                                 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
 425 
 426                 addr = virtqueue_get_used_addr(vq);
 427                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
 428                 writel((u32)(addr >> 32),
 429                                 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
 430 
 431                 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
 432         }
 433 
 434         vq->priv = info;
 435         info->vq = vq;
 436 
 437         spin_lock_irqsave(&vm_dev->lock, flags);
 438         list_add(&info->node, &vm_dev->virtqueues);
 439         spin_unlock_irqrestore(&vm_dev->lock, flags);
 440 
 441         return vq;
 442 
 443 error_bad_pfn:
 444         vring_del_virtqueue(vq);
 445 error_new_virtqueue:
 446         if (vm_dev->version == 1) {
 447                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
 448         } else {
 449                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
 450                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
 451         }
 452         kfree(info);
 453 error_kmalloc:
 454 error_available:
 455         return ERR_PTR(err);
 456 }
 457 
 458 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 459                        struct virtqueue *vqs[],
 460                        vq_callback_t *callbacks[],
 461                        const char * const names[],
 462                        const bool *ctx,
 463                        struct irq_affinity *desc)
 464 {
 465         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 466         int irq = platform_get_irq(vm_dev->pdev, 0);
 467         int i, err, queue_idx = 0;
 468 
 469         if (irq < 0) {
 470                 dev_err(&vdev->dev, "Cannot get IRQ resource\n");
 471                 return irq;
 472         }
 473 
 474         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
 475                         dev_name(&vdev->dev), vm_dev);
 476         if (err)
 477                 return err;
 478 
 479         for (i = 0; i < nvqs; ++i) {
 480                 if (!names[i]) {
 481                         vqs[i] = NULL;
 482                         continue;
 483                 }
 484 
 485                 vqs[i] = vm_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
 486                                      ctx ? ctx[i] : false);
 487                 if (IS_ERR(vqs[i])) {
 488                         vm_del_vqs(vdev);
 489                         return PTR_ERR(vqs[i]);
 490                 }
 491         }
 492 
 493         return 0;
 494 }
 495 
 496 static const char *vm_bus_name(struct virtio_device *vdev)
 497 {
 498         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 499 
 500         return vm_dev->pdev->name;
 501 }
 502 
 503 static const struct virtio_config_ops virtio_mmio_config_ops = {
 504         .get            = vm_get,
 505         .set            = vm_set,
 506         .generation     = vm_generation,
 507         .get_status     = vm_get_status,
 508         .set_status     = vm_set_status,
 509         .reset          = vm_reset,
 510         .find_vqs       = vm_find_vqs,
 511         .del_vqs        = vm_del_vqs,
 512         .get_features   = vm_get_features,
 513         .finalize_features = vm_finalize_features,
 514         .bus_name       = vm_bus_name,
 515 };
 516 
 517 
 518 static void virtio_mmio_release_dev(struct device *_d)
 519 {
 520         struct virtio_device *vdev =
 521                         container_of(_d, struct virtio_device, dev);
 522         struct virtio_mmio_device *vm_dev =
 523                         container_of(vdev, struct virtio_mmio_device, vdev);
 524         struct platform_device *pdev = vm_dev->pdev;
 525 
 526         devm_kfree(&pdev->dev, vm_dev);
 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         int rc;
 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.dev.release = virtio_mmio_release_dev;
 552         vm_dev->vdev.config = &virtio_mmio_config_ops;
 553         vm_dev->pdev = pdev;
 554         INIT_LIST_HEAD(&vm_dev->virtqueues);
 555         spin_lock_init(&vm_dev->lock);
 556 
 557         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
 558         if (vm_dev->base == NULL)
 559                 return -EFAULT;
 560 
 561         /* Check magic value */
 562         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
 563         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
 564                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
 565                 return -ENODEV;
 566         }
 567 
 568         /* Check device version */
 569         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
 570         if (vm_dev->version < 1 || vm_dev->version > 2) {
 571                 dev_err(&pdev->dev, "Version %ld not supported!\n",
 572                                 vm_dev->version);
 573                 return -ENXIO;
 574         }
 575 
 576         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
 577         if (vm_dev->vdev.id.device == 0) {
 578                 /*
 579                  * virtio-mmio device with an ID 0 is a (dummy) placeholder
 580                  * with no function. End probing now with no error reported.
 581                  */
 582                 return -ENODEV;
 583         }
 584         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
 585 
 586         if (vm_dev->version == 1) {
 587                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
 588 
 589                 rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
 590                 /*
 591                  * In the legacy case, ensure our coherently-allocated virtio
 592                  * ring will be at an address expressable as a 32-bit PFN.
 593                  */
 594                 if (!rc)
 595                         dma_set_coherent_mask(&pdev->dev,
 596                                               DMA_BIT_MASK(32 + PAGE_SHIFT));
 597         } else {
 598                 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
 599         }
 600         if (rc)
 601                 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
 602         if (rc)
 603                 dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
 604 
 605         platform_set_drvdata(pdev, vm_dev);
 606 
 607         rc = register_virtio_device(&vm_dev->vdev);
 608         if (rc)
 609                 put_device(&vm_dev->vdev.dev);
 610 
 611         return rc;
 612 }
 613 
 614 static int virtio_mmio_remove(struct platform_device *pdev)
 615 {
 616         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
 617         unregister_virtio_device(&vm_dev->vdev);
 618 
 619         return 0;
 620 }
 621 
 622 
 623 
 624 /* Devices list parameter */
 625 
 626 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
 627 
 628 static struct device vm_cmdline_parent = {
 629         .init_name = "virtio-mmio-cmdline",
 630 };
 631 
 632 static int vm_cmdline_parent_registered;
 633 static int vm_cmdline_id;
 634 
 635 static int vm_cmdline_set(const char *device,
 636                 const struct kernel_param *kp)
 637 {
 638         int err;
 639         struct resource resources[2] = {};
 640         char *str;
 641         long long int base, size;
 642         unsigned int irq;
 643         int processed, consumed = 0;
 644         struct platform_device *pdev;
 645 
 646         /* Consume "size" part of the command line parameter */
 647         size = memparse(device, &str);
 648 
 649         /* Get "@<base>:<irq>[:<id>]" chunks */
 650         processed = sscanf(str, "@%lli:%u%n:%d%n",
 651                         &base, &irq, &consumed,
 652                         &vm_cmdline_id, &consumed);
 653 
 654         /*
 655          * sscanf() must processes at least 2 chunks; also there
 656          * must be no extra characters after the last chunk, so
 657          * str[consumed] must be '\0'
 658          */
 659         if (processed < 2 || str[consumed])
 660                 return -EINVAL;
 661 
 662         resources[0].flags = IORESOURCE_MEM;
 663         resources[0].start = base;
 664         resources[0].end = base + size - 1;
 665 
 666         resources[1].flags = IORESOURCE_IRQ;
 667         resources[1].start = resources[1].end = irq;
 668 
 669         if (!vm_cmdline_parent_registered) {
 670                 err = device_register(&vm_cmdline_parent);
 671                 if (err) {
 672                         pr_err("Failed to register parent device!\n");
 673                         return err;
 674                 }
 675                 vm_cmdline_parent_registered = 1;
 676         }
 677 
 678         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
 679                        vm_cmdline_id,
 680                        (unsigned long long)resources[0].start,
 681                        (unsigned long long)resources[0].end,
 682                        (int)resources[1].start);
 683 
 684         pdev = platform_device_register_resndata(&vm_cmdline_parent,
 685                         "virtio-mmio", vm_cmdline_id++,
 686                         resources, ARRAY_SIZE(resources), NULL, 0);
 687 
 688         return PTR_ERR_OR_ZERO(pdev);
 689 }
 690 
 691 static int vm_cmdline_get_device(struct device *dev, void *data)
 692 {
 693         char *buffer = data;
 694         unsigned int len = strlen(buffer);
 695         struct platform_device *pdev = to_platform_device(dev);
 696 
 697         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
 698                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
 699                         (unsigned long long)pdev->resource[0].start,
 700                         (unsigned long long)pdev->resource[1].start,
 701                         pdev->id);
 702         return 0;
 703 }
 704 
 705 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
 706 {
 707         buffer[0] = '\0';
 708         device_for_each_child(&vm_cmdline_parent, buffer,
 709                         vm_cmdline_get_device);
 710         return strlen(buffer) + 1;
 711 }
 712 
 713 static const struct kernel_param_ops vm_cmdline_param_ops = {
 714         .set = vm_cmdline_set,
 715         .get = vm_cmdline_get,
 716 };
 717 
 718 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
 719 
 720 static int vm_unregister_cmdline_device(struct device *dev,
 721                 void *data)
 722 {
 723         platform_device_unregister(to_platform_device(dev));
 724 
 725         return 0;
 726 }
 727 
 728 static void vm_unregister_cmdline_devices(void)
 729 {
 730         if (vm_cmdline_parent_registered) {
 731                 device_for_each_child(&vm_cmdline_parent, NULL,
 732                                 vm_unregister_cmdline_device);
 733                 device_unregister(&vm_cmdline_parent);
 734                 vm_cmdline_parent_registered = 0;
 735         }
 736 }
 737 
 738 #else
 739 
 740 static void vm_unregister_cmdline_devices(void)
 741 {
 742 }
 743 
 744 #endif
 745 
 746 /* Platform driver */
 747 
 748 static const struct of_device_id virtio_mmio_match[] = {
 749         { .compatible = "virtio,mmio", },
 750         {},
 751 };
 752 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
 753 
 754 #ifdef CONFIG_ACPI
 755 static const struct acpi_device_id virtio_mmio_acpi_match[] = {
 756         { "LNRO0005", },
 757         { }
 758 };
 759 MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
 760 #endif
 761 
 762 static struct platform_driver virtio_mmio_driver = {
 763         .probe          = virtio_mmio_probe,
 764         .remove         = virtio_mmio_remove,
 765         .driver         = {
 766                 .name   = "virtio-mmio",
 767                 .of_match_table = virtio_mmio_match,
 768                 .acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
 769         },
 770 };
 771 
 772 static int __init virtio_mmio_init(void)
 773 {
 774         return platform_driver_register(&virtio_mmio_driver);
 775 }
 776 
 777 static void __exit virtio_mmio_exit(void)
 778 {
 779         platform_driver_unregister(&virtio_mmio_driver);
 780         vm_unregister_cmdline_devices();
 781 }
 782 
 783 module_init(virtio_mmio_init);
 784 module_exit(virtio_mmio_exit);
 785 
 786 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
 787 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
 788 MODULE_LICENSE("GPL");