root/drivers/misc/mic/vop/vop_main.c

DEFINITIONS

1. _vop_dev
2. _vop_desc_size
3. _vop_vq_config
4. _vop_vq_features
5. _vop_vq_configspace
6. _vop_total_desc_size
7. vop_get_features
8. vop_transport_features
9. vop_finalize_features
10. vop_get
11. vop_set
12. vop_get_status
13. vop_set_status
14. vop_reset_inform_host
15. vop_reset
16. vop_notify
17. vop_del_vq
18. vop_del_vqs
19. vop_new_virtqueue
20. vop_find_vq
21. vop_find_vqs
22. vop_virtio_intr_handler
23. vop_virtio_release_dev
24. _vop_add_device
25. vop_match_desc
26. vop_dc_to_vdev
27. _vop_handle_config_change
28. _vop_remove_device
29. _vop_scan_devices
30. vop_scan_devices
31. vop_hotplug_devices
32. vop_extint_handler
33. vop_driver_probe
34. vop_driver_remove

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Intel MIC Platform Software Stack (MPSS)
   4  *
   5  * Copyright(c) 2016 Intel Corporation.
   6  *
   7  * Adapted from:
   8  *
   9  * virtio for kvm on s390
  10  *
  11  * Copyright IBM Corp. 2008
  12  *
  13  *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
  14  *
  15  * Intel Virtio Over PCIe (VOP) driver.
  16  */
  17 #include <linux/delay.h>
  18 #include <linux/module.h>
  19 #include <linux/sched.h>
  20 #include <linux/dma-mapping.h>
  21 #include <linux/io-64-nonatomic-lo-hi.h>
  22 
  23 #include "vop_main.h"
  24 
  25 #define VOP_MAX_VRINGS 4
  26 
  27 /*
  28  * _vop_vdev - Allocated per virtio device instance injected by the peer.
  29  *
  30  * @vdev: Virtio device
  31  * @desc: Virtio device page descriptor
  32  * @dc: Virtio device control
  33  * @vpdev: VOP device which is the parent for this virtio device
  34  * @vr: Buffer for accessing the VRING
  35  * @used_virt: Virtual address of used ring
  36  * @used: DMA address of used ring
  37  * @used_size: Size of the used buffer
  38  * @reset_done: Track whether VOP reset is complete
  39  * @virtio_cookie: Cookie returned upon requesting a interrupt
  40  * @c2h_vdev_db: The doorbell used by the guest to interrupt the host
  41  * @h2c_vdev_db: The doorbell used by the host to interrupt the guest
  42  * @dnode: The destination node
  43  */
  44 struct _vop_vdev {
  45         struct virtio_device vdev;
  46         struct mic_device_desc __iomem *desc;
  47         struct mic_device_ctrl __iomem *dc;
  48         struct vop_device *vpdev;
  49         void __iomem *vr[VOP_MAX_VRINGS];
  50         void *used_virt[VOP_MAX_VRINGS];
  51         dma_addr_t used[VOP_MAX_VRINGS];
  52         int used_size[VOP_MAX_VRINGS];
  53         struct completion reset_done;
  54         struct mic_irq *virtio_cookie;
  55         int c2h_vdev_db;
  56         int h2c_vdev_db;
  57         int dnode;
  58 };
  59 
  60 #define to_vopvdev(vd) container_of(vd, struct _vop_vdev, vdev)
  61 
  62 #define _vop_aligned_desc_size(d) __mic_align(_vop_desc_size(d), 8)
  63 
  64 /* Helper API to obtain the parent of the virtio device */
  65 static inline struct device *_vop_dev(struct _vop_vdev *vdev)
  66 {
  67         return vdev->vdev.dev.parent;
  68 }
  69 
  70 static inline unsigned _vop_desc_size(struct mic_device_desc __iomem *desc)
  71 {
  72         return sizeof(*desc)
  73                 + ioread8(&desc->num_vq) * sizeof(struct mic_vqconfig)
  74                 + ioread8(&desc->feature_len) * 2
  75                 + ioread8(&desc->config_len);
  76 }
  77 
  78 static inline struct mic_vqconfig __iomem *
  79 _vop_vq_config(struct mic_device_desc __iomem *desc)
  80 {
  81         return (struct mic_vqconfig __iomem *)(desc + 1);
  82 }
  83 
  84 static inline u8 __iomem *
  85 _vop_vq_features(struct mic_device_desc __iomem *desc)
  86 {
  87         return (u8 __iomem *)(_vop_vq_config(desc) + ioread8(&desc->num_vq));
  88 }
  89 
  90 static inline u8 __iomem *
  91 _vop_vq_configspace(struct mic_device_desc __iomem *desc)
  92 {
  93         return _vop_vq_features(desc) + ioread8(&desc->feature_len) * 2;
  94 }
  95 
  96 static inline unsigned
  97 _vop_total_desc_size(struct mic_device_desc __iomem *desc)
  98 {
  99         return _vop_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl);
 100 }
 101 
 102 /* This gets the device's feature bits. */
 103 static u64 vop_get_features(struct virtio_device *vdev)
 104 {
 105         unsigned int i, bits;
 106         u64 features = 0;
 107         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 108         u8 __iomem *in_features = _vop_vq_features(desc);
 109         int feature_len = ioread8(&desc->feature_len);
 110 
 111         bits = min_t(unsigned, feature_len, sizeof(vdev->features)) * 8;
 112         for (i = 0; i < bits; i++)
 113                 if (ioread8(&in_features[i / 8]) & (BIT(i % 8)))
 114                         features |= BIT_ULL(i);
 115 
 116         return features;
 117 }
 118 
 119 static void vop_transport_features(struct virtio_device *vdev)
 120 {
 121         /*
 122          * Packed ring isn't enabled on virtio_vop for now,
 123          * because virtio_vop uses vring_new_virtqueue() which
 124          * creates virtio rings on preallocated memory.
 125          */
 126         __virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
 127 }
 128 
 129 static int vop_finalize_features(struct virtio_device *vdev)
 130 {
 131         unsigned int i, bits;
 132         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 133         u8 feature_len = ioread8(&desc->feature_len);
 134         /* Second half of bitmap is features we accept. */
 135         u8 __iomem *out_features =
 136                 _vop_vq_features(desc) + feature_len;
 137 
 138         /* Give virtio_ring a chance to accept features. */
 139         vring_transport_features(vdev);
 140 
 141         /* Give virtio_vop a chance to accept features. */
 142         vop_transport_features(vdev);
 143 
 144         memset_io(out_features, 0, feature_len);
 145         bits = min_t(unsigned, feature_len,
 146                      sizeof(vdev->features)) * 8;
 147         for (i = 0; i < bits; i++) {
 148                 if (__virtio_test_bit(vdev, i))
 149                         iowrite8(ioread8(&out_features[i / 8]) | (1 << (i % 8)),
 150                                  &out_features[i / 8]);
 151         }
 152         return 0;
 153 }
 154 
 155 /*
 156  * Reading and writing elements in config space
 157  */
 158 static void vop_get(struct virtio_device *vdev, unsigned int offset,
 159                     void *buf, unsigned len)
 160 {
 161         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 162 
 163         if (offset + len > ioread8(&desc->config_len))
 164                 return;
 165         memcpy_fromio(buf, _vop_vq_configspace(desc) + offset, len);
 166 }
 167 
 168 static void vop_set(struct virtio_device *vdev, unsigned int offset,
 169                     const void *buf, unsigned len)
 170 {
 171         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 172 
 173         if (offset + len > ioread8(&desc->config_len))
 174                 return;
 175         memcpy_toio(_vop_vq_configspace(desc) + offset, buf, len);
 176 }
 177 
 178 /*
 179  * The operations to get and set the status word just access the status
 180  * field of the device descriptor. set_status also interrupts the host
 181  * to tell about status changes.
 182  */
 183 static u8 vop_get_status(struct virtio_device *vdev)
 184 {
 185         return ioread8(&to_vopvdev(vdev)->desc->status);
 186 }
 187 
 188 static void vop_set_status(struct virtio_device *dev, u8 status)
 189 {
 190         struct _vop_vdev *vdev = to_vopvdev(dev);
 191         struct vop_device *vpdev = vdev->vpdev;
 192 
 193         if (!status)
 194                 return;
 195         iowrite8(status, &vdev->desc->status);
 196         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 197 }
 198 
 199 /* Inform host on a virtio device reset and wait for ack from host */
 200 static void vop_reset_inform_host(struct virtio_device *dev)
 201 {
 202         struct _vop_vdev *vdev = to_vopvdev(dev);
 203         struct mic_device_ctrl __iomem *dc = vdev->dc;
 204         struct vop_device *vpdev = vdev->vpdev;
 205         int retry;
 206 
 207         iowrite8(0, &dc->host_ack);
 208         iowrite8(1, &dc->vdev_reset);
 209         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 210 
 211         /* Wait till host completes all card accesses and acks the reset */
 212         for (retry = 100; retry--;) {
 213                 if (ioread8(&dc->host_ack))
 214                         break;
 215                 msleep(100);
 216         }
 217 
 218         dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
 219 
 220         /* Reset status to 0 in case we timed out */
 221         iowrite8(0, &vdev->desc->status);
 222 }
 223 
 224 static void vop_reset(struct virtio_device *dev)
 225 {
 226         struct _vop_vdev *vdev = to_vopvdev(dev);
 227 
 228         dev_dbg(_vop_dev(vdev), "%s: virtio id %d\n",
 229                 __func__, dev->id.device);
 230 
 231         vop_reset_inform_host(dev);
 232         complete_all(&vdev->reset_done);
 233 }
 234 
 235 /*
 236  * The virtio_ring code calls this API when it wants to notify the Host.
 237  */
 238 static bool vop_notify(struct virtqueue *vq)
 239 {
 240         struct _vop_vdev *vdev = vq->priv;
 241         struct vop_device *vpdev = vdev->vpdev;
 242 
 243         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 244         return true;
 245 }
 246 
 247 static void vop_del_vq(struct virtqueue *vq, int n)
 248 {
 249         struct _vop_vdev *vdev = to_vopvdev(vq->vdev);
 250         struct vop_device *vpdev = vdev->vpdev;
 251 
 252         dma_unmap_single(&vpdev->dev, vdev->used[n],
 253                          vdev->used_size[n], DMA_BIDIRECTIONAL);
 254         free_pages((unsigned long)vdev->used_virt[n],
 255                    get_order(vdev->used_size[n]));
 256         vring_del_virtqueue(vq);
 257         vpdev->hw_ops->unmap(vpdev, vdev->vr[n]);
 258         vdev->vr[n] = NULL;
 259 }
 260 
 261 static void vop_del_vqs(struct virtio_device *dev)
 262 {
 263         struct _vop_vdev *vdev = to_vopvdev(dev);
 264         struct virtqueue *vq, *n;
 265         int idx = 0;
 266 
 267         dev_dbg(_vop_dev(vdev), "%s\n", __func__);
 268 
 269         list_for_each_entry_safe(vq, n, &dev->vqs, list)
 270                 vop_del_vq(vq, idx++);
 271 }
 272 
 273 static struct virtqueue *vop_new_virtqueue(unsigned int index,
 274                                       unsigned int num,
 275                                       struct virtio_device *vdev,
 276                                       bool context,
 277                                       void *pages,
 278                                       bool (*notify)(struct virtqueue *vq),
 279                                       void (*callback)(struct virtqueue *vq),
 280                                       const char *name,
 281                                       void *used)
 282 {
 283         bool weak_barriers = false;
 284         struct vring vring;
 285 
 286         vring_init(&vring, num, pages, MIC_VIRTIO_RING_ALIGN);
 287         vring.used = used;
 288 
 289         return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
 290                                      notify, callback, name);
 291 }
 292 
 293 /*
 294  * This routine will assign vring's allocated in host/io memory. Code in
 295  * virtio_ring.c however continues to access this io memory as if it were local
 296  * memory without io accessors.
 297  */
 298 static struct virtqueue *vop_find_vq(struct virtio_device *dev,
 299                                      unsigned index,
 300                                      void (*callback)(struct virtqueue *vq),
 301                                      const char *name, bool ctx)
 302 {
 303         struct _vop_vdev *vdev = to_vopvdev(dev);
 304         struct vop_device *vpdev = vdev->vpdev;
 305         struct mic_vqconfig __iomem *vqconfig;
 306         struct mic_vqconfig config;
 307         struct virtqueue *vq;
 308         void __iomem *va;
 309         struct _mic_vring_info __iomem *info;
 310         void *used;
 311         int vr_size, _vr_size, err, magic;
 312         u8 type = ioread8(&vdev->desc->type);
 313 
 314         if (index >= ioread8(&vdev->desc->num_vq))
 315                 return ERR_PTR(-ENOENT);
 316 
 317         if (!name)
 318                 return ERR_PTR(-ENOENT);
 319 
 320         /* First assign the vring's allocated in host memory */
 321         vqconfig = _vop_vq_config(vdev->desc) + index;
 322         memcpy_fromio(&config, vqconfig, sizeof(config));
 323         _vr_size = vring_size(le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN);
 324         vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info));
 325         va = vpdev->hw_ops->remap(vpdev, le64_to_cpu(config.address), vr_size);
 326         if (!va)
 327                 return ERR_PTR(-ENOMEM);
 328         vdev->vr[index] = va;
 329         memset_io(va, 0x0, _vr_size);
 330 
 331         info = va + _vr_size;
 332         magic = ioread32(&info->magic);
 333 
 334         if (WARN(magic != MIC_MAGIC + type + index, "magic mismatch")) {
 335                 err = -EIO;
 336                 goto unmap;
 337         }
 338 
 339         vdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 +
 340                                              sizeof(struct vring_used_elem) *
 341                                              le16_to_cpu(config.num));
 342         used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 343                                         get_order(vdev->used_size[index]));
 344         vdev->used_virt[index] = used;
 345         if (!used) {
 346                 err = -ENOMEM;
 347                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 348                         __func__, __LINE__, err);
 349                 goto unmap;
 350         }
 351 
 352         vq = vop_new_virtqueue(index, le16_to_cpu(config.num), dev, ctx,
 353                                (void __force *)va, vop_notify, callback,
 354                                name, used);
 355         if (!vq) {
 356                 err = -ENOMEM;
 357                 goto free_used;
 358         }
 359 
 360         vdev->used[index] = dma_map_single(&vpdev->dev, used,
 361                                             vdev->used_size[index],
 362                                             DMA_BIDIRECTIONAL);
 363         if (dma_mapping_error(&vpdev->dev, vdev->used[index])) {
 364                 err = -ENOMEM;
 365                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 366                         __func__, __LINE__, err);
 367                 goto del_vq;
 368         }
 369         writeq(vdev->used[index], &vqconfig->used_address);
 370 
 371         vq->priv = vdev;
 372         return vq;
 373 del_vq:
 374         vring_del_virtqueue(vq);
 375 free_used:
 376         free_pages((unsigned long)used,
 377                    get_order(vdev->used_size[index]));
 378 unmap:
 379         vpdev->hw_ops->unmap(vpdev, vdev->vr[index]);
 380         return ERR_PTR(err);
 381 }
 382 
 383 static int vop_find_vqs(struct virtio_device *dev, unsigned nvqs,
 384                         struct virtqueue *vqs[],
 385                         vq_callback_t *callbacks[],
 386                         const char * const names[], const bool *ctx,
 387                         struct irq_affinity *desc)
 388 {
 389         struct _vop_vdev *vdev = to_vopvdev(dev);
 390         struct vop_device *vpdev = vdev->vpdev;
 391         struct mic_device_ctrl __iomem *dc = vdev->dc;
 392         int i, err, retry, queue_idx = 0;
 393 
 394         /* We must have this many virtqueues. */
 395         if (nvqs > ioread8(&vdev->desc->num_vq))
 396                 return -ENOENT;
 397 
 398         for (i = 0; i < nvqs; ++i) {
 399                 if (!names[i]) {
 400                         vqs[i] = NULL;
 401                         continue;
 402                 }
 403 
 404                 dev_dbg(_vop_dev(vdev), "%s: %d: %s\n",
 405                         __func__, i, names[i]);
 406                 vqs[i] = vop_find_vq(dev, queue_idx++, callbacks[i], names[i],
 407                                      ctx ? ctx[i] : false);
 408                 if (IS_ERR(vqs[i])) {
 409                         err = PTR_ERR(vqs[i]);
 410                         goto error;
 411                 }
 412         }
 413 
 414         iowrite8(1, &dc->used_address_updated);
 415         /*
 416          * Send an interrupt to the host to inform it that used
 417          * rings have been re-assigned.
 418          */
 419         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 420         for (retry = 100; --retry;) {
 421                 if (!ioread8(&dc->used_address_updated))
 422                         break;
 423                 msleep(100);
 424         }
 425 
 426         dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
 427         if (!retry) {
 428                 err = -ENODEV;
 429                 goto error;
 430         }
 431 
 432         return 0;
 433 error:
 434         vop_del_vqs(dev);
 435         return err;
 436 }
 437 
 438 /*
 439  * The config ops structure as defined by virtio config
 440  */
 441 static struct virtio_config_ops vop_vq_config_ops = {
 442         .get_features = vop_get_features,
 443         .finalize_features = vop_finalize_features,
 444         .get = vop_get,
 445         .set = vop_set,
 446         .get_status = vop_get_status,
 447         .set_status = vop_set_status,
 448         .reset = vop_reset,
 449         .find_vqs = vop_find_vqs,
 450         .del_vqs = vop_del_vqs,
 451 };
 452 
 453 static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
 454 {
 455         struct _vop_vdev *vdev = data;
 456         struct vop_device *vpdev = vdev->vpdev;
 457         struct virtqueue *vq;
 458 
 459         vpdev->hw_ops->ack_interrupt(vpdev, vdev->h2c_vdev_db);
 460         list_for_each_entry(vq, &vdev->vdev.vqs, list)
 461                 vring_interrupt(0, vq);
 462 
 463         return IRQ_HANDLED;
 464 }
 465 
 466 static void vop_virtio_release_dev(struct device *_d)
 467 {
 468         struct virtio_device *vdev =
 469                         container_of(_d, struct virtio_device, dev);
 470         struct _vop_vdev *vop_vdev =
 471                         container_of(vdev, struct _vop_vdev, vdev);
 472 
 473         kfree(vop_vdev);
 474 }
 475 
 476 /*
 477  * adds a new device and register it with virtio
 478  * appropriate drivers are loaded by the device model
 479  */
 480 static int _vop_add_device(struct mic_device_desc __iomem *d,
 481                            unsigned int offset, struct vop_device *vpdev,
 482                            int dnode)
 483 {
 484         struct _vop_vdev *vdev, *reg_dev = NULL;
 485         int ret;
 486         u8 type = ioread8(&d->type);
 487 
 488         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 489         if (!vdev)
 490                 return -ENOMEM;
 491 
 492         vdev->vpdev = vpdev;
 493         vdev->vdev.dev.parent = &vpdev->dev;
 494         vdev->vdev.dev.release = vop_virtio_release_dev;
 495         vdev->vdev.id.device = type;
 496         vdev->vdev.config = &vop_vq_config_ops;
 497         vdev->desc = d;
 498         vdev->dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 499         vdev->dnode = dnode;
 500         vdev->vdev.priv = (void *)(unsigned long)dnode;
 501         init_completion(&vdev->reset_done);
 502 
 503         vdev->h2c_vdev_db = vpdev->hw_ops->next_db(vpdev);
 504         vdev->virtio_cookie = vpdev->hw_ops->request_irq(vpdev,
 505                         vop_virtio_intr_handler, "virtio intr",
 506                         vdev, vdev->h2c_vdev_db);
 507         if (IS_ERR(vdev->virtio_cookie)) {
 508                 ret = PTR_ERR(vdev->virtio_cookie);
 509                 goto kfree;
 510         }
 511         iowrite8((u8)vdev->h2c_vdev_db, &vdev->dc->h2c_vdev_db);
 512         vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
 513 
 514         ret = register_virtio_device(&vdev->vdev);
 515         reg_dev = vdev;
 516         if (ret) {
 517                 dev_err(_vop_dev(vdev),
 518                         "Failed to register vop device %u type %u\n",
 519                         offset, type);
 520                 goto free_irq;
 521         }
 522         writeq((unsigned long)vdev, &vdev->dc->vdev);
 523         dev_dbg(_vop_dev(vdev), "%s: registered vop device %u type %u vdev %p\n",
 524                 __func__, offset, type, vdev);
 525 
 526         return 0;
 527 
 528 free_irq:
 529         vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 530 kfree:
 531         if (reg_dev)
 532                 put_device(&vdev->vdev.dev);
 533         else
 534                 kfree(vdev);
 535         return ret;
 536 }
 537 
 538 /*
 539  * match for a vop device with a specific desc pointer
 540  */
 541 static int vop_match_desc(struct device *dev, void *data)
 542 {
 543         struct virtio_device *_dev = dev_to_virtio(dev);
 544         struct _vop_vdev *vdev = to_vopvdev(_dev);
 545 
 546         return vdev->desc == (void __iomem *)data;
 547 }
 548 
 549 static struct _vop_vdev *vop_dc_to_vdev(struct mic_device_ctrl *dc)
 550 {
 551         return (struct _vop_vdev *)(unsigned long)readq(&dc->vdev);
 552 }
 553 
 554 static void _vop_handle_config_change(struct mic_device_desc __iomem *d,
 555                                       unsigned int offset,
 556                                       struct vop_device *vpdev)
 557 {
 558         struct mic_device_ctrl __iomem *dc
 559                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 560         struct _vop_vdev *vdev = vop_dc_to_vdev(dc);
 561 
 562         if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED)
 563                 return;
 564 
 565         dev_dbg(&vpdev->dev, "%s %d\n", __func__, __LINE__);
 566         virtio_config_changed(&vdev->vdev);
 567         iowrite8(1, &dc->guest_ack);
 568 }
 569 
 570 /*
 571  * removes a virtio device if a hot remove event has been
 572  * requested by the host.
 573  */
 574 static int _vop_remove_device(struct mic_device_desc __iomem *d,
 575                               unsigned int offset, struct vop_device *vpdev)
 576 {
 577         struct mic_device_ctrl __iomem *dc
 578                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 579         struct _vop_vdev *vdev = vop_dc_to_vdev(dc);
 580         u8 status;
 581         int ret = -1;
 582 
 583         if (ioread8(&dc->config_change) == MIC_VIRTIO_PARAM_DEV_REMOVE) {
 584                 struct device *dev = get_device(&vdev->vdev.dev);
 585 
 586                 dev_dbg(&vpdev->dev,
 587                         "%s %d config_change %d type %d vdev %p\n",
 588                         __func__, __LINE__,
 589                         ioread8(&dc->config_change), ioread8(&d->type), vdev);
 590                 status = ioread8(&d->status);
 591                 reinit_completion(&vdev->reset_done);
 592                 unregister_virtio_device(&vdev->vdev);
 593                 vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 594                 iowrite8(-1, &dc->h2c_vdev_db);
 595                 if (status & VIRTIO_CONFIG_S_DRIVER_OK)
 596                         wait_for_completion(&vdev->reset_done);
 597                 put_device(dev);
 598                 iowrite8(1, &dc->guest_ack);
 599                 dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
 600                         __func__, __LINE__, ioread8(&dc->guest_ack));
 601                 iowrite8(-1, &d->type);
 602                 ret = 0;
 603         }
 604         return ret;
 605 }
 606 
 607 #define REMOVE_DEVICES true
 608 
 609 static void _vop_scan_devices(void __iomem *dp, struct vop_device *vpdev,
 610                               bool remove, int dnode)
 611 {
 612         s8 type;
 613         unsigned int i;
 614         struct mic_device_desc __iomem *d;
 615         struct mic_device_ctrl __iomem *dc;
 616         struct device *dev;
 617         int ret;
 618 
 619         for (i = sizeof(struct mic_bootparam);
 620                         i < MIC_DP_SIZE; i += _vop_total_desc_size(d)) {
 621                 d = dp + i;
 622                 dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 623                 /*
 624                  * This read barrier is paired with the corresponding write
 625                  * barrier on the host which is inserted before adding or
 626                  * removing a virtio device descriptor, by updating the type.
 627                  */
 628                 rmb();
 629                 type = ioread8(&d->type);
 630 
 631                 /* end of list */
 632                 if (type == 0)
 633                         break;
 634 
 635                 if (type == -1)
 636                         continue;
 637 
 638                 /* device already exists */
 639                 dev = device_find_child(&vpdev->dev, (void __force *)d,
 640                                         vop_match_desc);
 641                 if (dev) {
 642                         if (remove)
 643                                 iowrite8(MIC_VIRTIO_PARAM_DEV_REMOVE,
 644                                          &dc->config_change);
 645                         put_device(dev);
 646                         _vop_handle_config_change(d, i, vpdev);
 647                         ret = _vop_remove_device(d, i, vpdev);
 648                         if (remove) {
 649                                 iowrite8(0, &dc->config_change);
 650                                 iowrite8(0, &dc->guest_ack);
 651                         }
 652                         continue;
 653                 }
 654 
 655                 /* new device */
 656                 dev_dbg(&vpdev->dev, "%s %d Adding new virtio device %p\n",
 657                         __func__, __LINE__, d);
 658                 if (!remove)
 659                         _vop_add_device(d, i, vpdev, dnode);
 660         }
 661 }
 662 
 663 static void vop_scan_devices(struct vop_info *vi,
 664                              struct vop_device *vpdev, bool remove)
 665 {
 666         void __iomem *dp = vpdev->hw_ops->get_remote_dp(vpdev);
 667 
 668         if (!dp)
 669                 return;
 670         mutex_lock(&vi->vop_mutex);
 671         _vop_scan_devices(dp, vpdev, remove, vpdev->dnode);
 672         mutex_unlock(&vi->vop_mutex);
 673 }
 674 
 675 /*
 676  * vop_hotplug_device tries to find changes in the device page.
 677  */
 678 static void vop_hotplug_devices(struct work_struct *work)
 679 {
 680         struct vop_info *vi = container_of(work, struct vop_info,
 681                                              hotplug_work);
 682 
 683         vop_scan_devices(vi, vi->vpdev, !REMOVE_DEVICES);
 684 }
 685 
 686 /*
 687  * Interrupt handler for hot plug/config changes etc.
 688  */
 689 static irqreturn_t vop_extint_handler(int irq, void *data)
 690 {
 691         struct vop_info *vi = data;
 692         struct mic_bootparam __iomem *bp;
 693         struct vop_device *vpdev = vi->vpdev;
 694 
 695         bp = vpdev->hw_ops->get_remote_dp(vpdev);
 696         dev_dbg(&vpdev->dev, "%s %d hotplug work\n",
 697                 __func__, __LINE__);
 698         vpdev->hw_ops->ack_interrupt(vpdev, ioread8(&bp->h2c_config_db));
 699         schedule_work(&vi->hotplug_work);
 700         return IRQ_HANDLED;
 701 }
 702 
 703 static int vop_driver_probe(struct vop_device *vpdev)
 704 {
 705         struct vop_info *vi;
 706         int rc;
 707 
 708         vi = kzalloc(sizeof(*vi), GFP_KERNEL);
 709         if (!vi) {
 710                 rc = -ENOMEM;
 711                 goto exit;
 712         }
 713         dev_set_drvdata(&vpdev->dev, vi);
 714         vi->vpdev = vpdev;
 715 
 716         mutex_init(&vi->vop_mutex);
 717         INIT_WORK(&vi->hotplug_work, vop_hotplug_devices);
 718         if (vpdev->dnode) {
 719                 rc = vop_host_init(vi);
 720                 if (rc < 0)
 721                         goto free;
 722         } else {
 723                 struct mic_bootparam __iomem *bootparam;
 724 
 725                 vop_scan_devices(vi, vpdev, !REMOVE_DEVICES);
 726 
 727                 vi->h2c_config_db = vpdev->hw_ops->next_db(vpdev);
 728                 vi->cookie = vpdev->hw_ops->request_irq(vpdev,
 729                                                         vop_extint_handler,
 730                                                         "virtio_config_intr",
 731                                                         vi, vi->h2c_config_db);
 732                 if (IS_ERR(vi->cookie)) {
 733                         rc = PTR_ERR(vi->cookie);
 734                         goto free;
 735                 }
 736                 bootparam = vpdev->hw_ops->get_remote_dp(vpdev);
 737                 iowrite8(vi->h2c_config_db, &bootparam->h2c_config_db);
 738         }
 739         vop_init_debugfs(vi);
 740         return 0;
 741 free:
 742         kfree(vi);
 743 exit:
 744         return rc;
 745 }
 746 
 747 static void vop_driver_remove(struct vop_device *vpdev)
 748 {
 749         struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
 750 
 751         if (vpdev->dnode) {
 752                 vop_host_uninit(vi);
 753         } else {
 754                 struct mic_bootparam __iomem *bootparam =
 755                         vpdev->hw_ops->get_remote_dp(vpdev);
 756                 if (bootparam)
 757                         iowrite8(-1, &bootparam->h2c_config_db);
 758                 vpdev->hw_ops->free_irq(vpdev, vi->cookie, vi);
 759                 flush_work(&vi->hotplug_work);
 760                 vop_scan_devices(vi, vpdev, REMOVE_DEVICES);
 761         }
 762         vop_exit_debugfs(vi);
 763         kfree(vi);
 764 }
 765 
 766 static struct vop_device_id id_table[] = {
 767         { VOP_DEV_TRNSP, VOP_DEV_ANY_ID },
 768         { 0 },
 769 };
 770 
 771 static struct vop_driver vop_driver = {
 772         .driver.name =  KBUILD_MODNAME,
 773         .driver.owner = THIS_MODULE,
 774         .id_table = id_table,
 775         .probe = vop_driver_probe,
 776         .remove = vop_driver_remove,
 777 };
 778 
 779 module_vop_driver(vop_driver);
 780 
 781 MODULE_DEVICE_TABLE(mbus, id_table);
 782 MODULE_AUTHOR("Intel Corporation");
 783 MODULE_DESCRIPTION("Intel(R) Virtio Over PCIe (VOP) driver");
 784 MODULE_LICENSE("GPL v2");