drivers/misc/mic/vop/vop_main.c

   1 /*
   2  * Intel MIC Platform Software Stack (MPSS)
   3  *
   4  * Copyright(c) 2016 Intel Corporation.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License, version 2, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful, but
  11  * WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  13  * General Public License for more details.
  14  *
  15  * The full GNU General Public License is included in this distribution in
  16  * the file called "COPYING".
  17  *
  18  * Adapted from:
  19  *
  20  * virtio for kvm on s390
  21  *
  22  * Copyright IBM Corp. 2008
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License (version 2 only)
  26  * as published by the Free Software Foundation.
  27  *
  28  *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
  29  *
  30  * Intel Virtio Over PCIe (VOP) driver.
  31  *
  32  */
  33 #include <linux/delay.h>
  34 #include <linux/module.h>
  35 #include <linux/sched.h>
  36 #include <linux/dma-mapping.h>
  37
  38 #include "vop_main.h"
  39
  40 #define VOP_MAX_VRINGS 4
  41
  42 /*
  43  * _vop_vdev - Allocated per virtio device instance injected by the peer.
  44  *
  45  * @vdev: Virtio device
  46  * @desc: Virtio device page descriptor
  47  * @dc: Virtio device control
  48  * @vpdev: VOP device which is the parent for this virtio device
  49  * @vr: Buffer for accessing the VRING
  50  * @used_virt: Virtual address of used ring
  51  * @used: DMA address of used ring
  52  * @used_size: Size of the used buffer
  53  * @reset_done: Track whether VOP reset is complete
  54  * @virtio_cookie: Cookie returned upon requesting a interrupt
  55  * @c2h_vdev_db: The doorbell used by the guest to interrupt the host
  56  * @h2c_vdev_db: The doorbell used by the host to interrupt the guest
  57  * @dnode: The destination node
  58  */
  59 struct _vop_vdev {
  60         struct virtio_device vdev;
  61         struct mic_device_desc __iomem *desc;
  62         struct mic_device_ctrl __iomem *dc;
  63         struct vop_device *vpdev;
  64         void __iomem *vr[VOP_MAX_VRINGS];
  65         void *used_virt[VOP_MAX_VRINGS];
  66         dma_addr_t used[VOP_MAX_VRINGS];
  67         int used_size[VOP_MAX_VRINGS];
  68         struct completion reset_done;
  69         struct mic_irq *virtio_cookie;
  70         int c2h_vdev_db;
  71         int h2c_vdev_db;
  72         int dnode;
  73 };
  74
  75 #define to_vopvdev(vd) container_of(vd, struct _vop_vdev, vdev)
  76
  77 #define _vop_aligned_desc_size(d) __mic_align(_vop_desc_size(d), 8)
  78
  79 /* Helper API to obtain the parent of the virtio device */
  80 static inline struct device *_vop_dev(struct _vop_vdev *vdev)
  81 {
  82         return vdev->vdev.dev.parent;
  83 }
  84
  85 static inline unsigned _vop_desc_size(struct mic_device_desc __iomem *desc)
  86 {
  87         return sizeof(*desc)
  88                 + ioread8(&desc->num_vq) * sizeof(struct mic_vqconfig)
  89                 + ioread8(&desc->feature_len) * 2
  90                 + ioread8(&desc->config_len);
  91 }
  92
  93 static inline struct mic_vqconfig __iomem *
  94 _vop_vq_config(struct mic_device_desc __iomem *desc)
  95 {
  96         return (struct mic_vqconfig __iomem *)(desc + 1);
  97 }
  98
  99 static inline u8 __iomem *
 100 _vop_vq_features(struct mic_device_desc __iomem *desc)
 101 {
 102         return (u8 __iomem *)(_vop_vq_config(desc) + ioread8(&desc->num_vq));
 103 }
 104
 105 static inline u8 __iomem *
 106 _vop_vq_configspace(struct mic_device_desc __iomem *desc)
 107 {
 108         return _vop_vq_features(desc) + ioread8(&desc->feature_len) * 2;
 109 }
 110
 111 static inline unsigned
 112 _vop_total_desc_size(struct mic_device_desc __iomem *desc)
 113 {
 114         return _vop_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl);
 115 }
 116
 117 /* This gets the device's feature bits. */
 118 static u64 vop_get_features(struct virtio_device *vdev)
 119 {
 120         unsigned int i, bits;
 121         u32 features = 0;
 122         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 123         u8 __iomem *in_features = _vop_vq_features(desc);
 124         int feature_len = ioread8(&desc->feature_len);
 125
 126         bits = min_t(unsigned, feature_len, sizeof(vdev->features)) * 8;
 127         for (i = 0; i < bits; i++)
 128                 if (ioread8(&in_features[i / 8]) & (BIT(i % 8)))
 129                         features |= BIT(i);
 130
 131         return features;
 132 }
 133
 134 static void vop_transport_features(struct virtio_device *vdev)
 135 {
 136         /*
 137          * Packed ring isn't enabled on virtio_vop for now,
 138          * because virtio_vop uses vring_new_virtqueue() which
 139          * creates virtio rings on preallocated memory.
 140          */
 141         __virtio_clear_bit(vdev, VIRTIO_F_RING_PACKED);
 142 }
 143
 144 static int vop_finalize_features(struct virtio_device *vdev)
 145 {
 146         unsigned int i, bits;
 147         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 148         u8 feature_len = ioread8(&desc->feature_len);
 149         /* Second half of bitmap is features we accept. */
 150         u8 __iomem *out_features =
 151                 _vop_vq_features(desc) + feature_len;
 152
 153         /* Give virtio_ring a chance to accept features. */
 154         vring_transport_features(vdev);
 155
 156         /* Give virtio_vop a chance to accept features. */
 157         vop_transport_features(vdev);
 158
 159         memset_io(out_features, 0, feature_len);
 160         bits = min_t(unsigned, feature_len,
 161                      sizeof(vdev->features)) * 8;
 162         for (i = 0; i < bits; i++) {
 163                 if (__virtio_test_bit(vdev, i))
 164                         iowrite8(ioread8(&out_features[i / 8]) | (1 << (i % 8)),
 165                                  &out_features[i / 8]);
 166         }
 167         return 0;
 168 }
 169
 170 /*
 171  * Reading and writing elements in config space
 172  */
 173 static void vop_get(struct virtio_device *vdev, unsigned int offset,
 174                     void *buf, unsigned len)
 175 {
 176         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 177
 178         if (offset + len > ioread8(&desc->config_len))
 179                 return;
 180         memcpy_fromio(buf, _vop_vq_configspace(desc) + offset, len);
 181 }
 182
 183 static void vop_set(struct virtio_device *vdev, unsigned int offset,
 184                     const void *buf, unsigned len)
 185 {
 186         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 187
 188         if (offset + len > ioread8(&desc->config_len))
 189                 return;
 190         memcpy_toio(_vop_vq_configspace(desc) + offset, buf, len);
 191 }
 192
 193 /*
 194  * The operations to get and set the status word just access the status
 195  * field of the device descriptor. set_status also interrupts the host
 196  * to tell about status changes.
 197  */
 198 static u8 vop_get_status(struct virtio_device *vdev)
 199 {
 200         return ioread8(&to_vopvdev(vdev)->desc->status);
 201 }
 202
 203 static void vop_set_status(struct virtio_device *dev, u8 status)
 204 {
 205         struct _vop_vdev *vdev = to_vopvdev(dev);
 206         struct vop_device *vpdev = vdev->vpdev;
 207
 208         if (!status)
 209                 return;
 210         iowrite8(status, &vdev->desc->status);
 211         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 212 }
 213
 214 /* Inform host on a virtio device reset and wait for ack from host */
 215 static void vop_reset_inform_host(struct virtio_device *dev)
 216 {
 217         struct _vop_vdev *vdev = to_vopvdev(dev);
 218         struct mic_device_ctrl __iomem *dc = vdev->dc;
 219         struct vop_device *vpdev = vdev->vpdev;
 220         int retry;
 221
 222         iowrite8(0, &dc->host_ack);
 223         iowrite8(1, &dc->vdev_reset);
 224         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 225
 226         /* Wait till host completes all card accesses and acks the reset */
 227         for (retry = 100; retry--;) {
 228                 if (ioread8(&dc->host_ack))
 229                         break;
 230                 msleep(100);
 231         };
 232
 233         dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
 234
 235         /* Reset status to 0 in case we timed out */
 236         iowrite8(0, &vdev->desc->status);
 237 }
 238
 239 static void vop_reset(struct virtio_device *dev)
 240 {
 241         struct _vop_vdev *vdev = to_vopvdev(dev);
 242
 243         dev_dbg(_vop_dev(vdev), "%s: virtio id %d\n",
 244                 __func__, dev->id.device);
 245
 246         vop_reset_inform_host(dev);
 247         complete_all(&vdev->reset_done);
 248 }
 249
 250 /*
 251  * The virtio_ring code calls this API when it wants to notify the Host.
 252  */
 253 static bool vop_notify(struct virtqueue *vq)
 254 {
 255         struct _vop_vdev *vdev = vq->priv;
 256         struct vop_device *vpdev = vdev->vpdev;
 257
 258         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 259         return true;
 260 }
 261
 262 static void vop_del_vq(struct virtqueue *vq, int n)
 263 {
 264         struct _vop_vdev *vdev = to_vopvdev(vq->vdev);
 265         struct vop_device *vpdev = vdev->vpdev;
 266
 267         dma_unmap_single(&vpdev->dev, vdev->used[n],
 268                          vdev->used_size[n], DMA_BIDIRECTIONAL);
 269         free_pages((unsigned long)vdev->used_virt[n],
 270                    get_order(vdev->used_size[n]));
 271         vring_del_virtqueue(vq);
 272         vpdev->hw_ops->iounmap(vpdev, vdev->vr[n]);
 273         vdev->vr[n] = NULL;
 274 }
 275
 276 static void vop_del_vqs(struct virtio_device *dev)
 277 {
 278         struct _vop_vdev *vdev = to_vopvdev(dev);
 279         struct virtqueue *vq, *n;
 280         int idx = 0;
 281
 282         dev_dbg(_vop_dev(vdev), "%s\n", __func__);
 283
 284         list_for_each_entry_safe(vq, n, &dev->vqs, list)
 285                 vop_del_vq(vq, idx++);
 286 }
 287
 288 static struct virtqueue *vop_new_virtqueue(unsigned int index,
 289                                       unsigned int num,
 290                                       struct virtio_device *vdev,
 291                                       bool context,
 292                                       void *pages,
 293                                       bool (*notify)(struct virtqueue *vq),
 294                                       void (*callback)(struct virtqueue *vq),
 295                                       const char *name,
 296                                       void *used)
 297 {
 298         bool weak_barriers = false;
 299         struct vring vring;
 300
 301         vring_init(&vring, num, pages, MIC_VIRTIO_RING_ALIGN);
 302         vring.used = used;
 303
 304         return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
 305                                      notify, callback, name);
 306 }
 307
 308 /*
 309  * This routine will assign vring's allocated in host/io memory. Code in
 310  * virtio_ring.c however continues to access this io memory as if it were local
 311  * memory without io accessors.
 312  */
 313 static struct virtqueue *vop_find_vq(struct virtio_device *dev,
 314                                      unsigned index,
 315                                      void (*callback)(struct virtqueue *vq),
 316                                      const char *name, bool ctx)
 317 {
 318         struct _vop_vdev *vdev = to_vopvdev(dev);
 319         struct vop_device *vpdev = vdev->vpdev;
 320         struct mic_vqconfig __iomem *vqconfig;
 321         struct mic_vqconfig config;
 322         struct virtqueue *vq;
 323         void __iomem *va;
 324         struct _mic_vring_info __iomem *info;
 325         void *used;
 326         int vr_size, _vr_size, err, magic;
 327         u8 type = ioread8(&vdev->desc->type);
 328
 329         if (index >= ioread8(&vdev->desc->num_vq))
 330                 return ERR_PTR(-ENOENT);
 331
 332         if (!name)
 333                 return ERR_PTR(-ENOENT);
 334
 335         /* First assign the vring's allocated in host memory */
 336         vqconfig = _vop_vq_config(vdev->desc) + index;
 337         memcpy_fromio(&config, vqconfig, sizeof(config));
 338         _vr_size = vring_size(le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN);
 339         vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info));
 340         va = vpdev->hw_ops->ioremap(vpdev, le64_to_cpu(config.address),
 341                         vr_size);
 342         if (!va)
 343                 return ERR_PTR(-ENOMEM);
 344         vdev->vr[index] = va;
 345         memset_io(va, 0x0, _vr_size);
 346
 347         info = va + _vr_size;
 348         magic = ioread32(&info->magic);
 349
 350         if (WARN(magic != MIC_MAGIC + type + index, "magic mismatch")) {
 351                 err = -EIO;
 352                 goto unmap;
 353         }
 354
 355         vdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 +
 356                                              sizeof(struct vring_used_elem) *
 357                                              le16_to_cpu(config.num));
 358         used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 359                                         get_order(vdev->used_size[index]));
 360         vdev->used_virt[index] = used;
 361         if (!used) {
 362                 err = -ENOMEM;
 363                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 364                         __func__, __LINE__, err);
 365                 goto unmap;
 366         }
 367
 368         vq = vop_new_virtqueue(index, le16_to_cpu(config.num), dev, ctx,
 369                                (void __force *)va, vop_notify, callback,
 370                                name, used);
 371         if (!vq) {
 372                 err = -ENOMEM;
 373                 goto free_used;
 374         }
 375
 376         vdev->used[index] = dma_map_single(&vpdev->dev, used,
 377                                             vdev->used_size[index],
 378                                             DMA_BIDIRECTIONAL);
 379         if (dma_mapping_error(&vpdev->dev, vdev->used[index])) {
 380                 err = -ENOMEM;
 381                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 382                         __func__, __LINE__, err);
 383                 goto del_vq;
 384         }
 385         writeq(vdev->used[index], &vqconfig->used_address);
 386
 387         vq->priv = vdev;
 388         return vq;
 389 del_vq:
 390         vring_del_virtqueue(vq);
 391 free_used:
 392         free_pages((unsigned long)used,
 393                    get_order(vdev->used_size[index]));
 394 unmap:
 395         vpdev->hw_ops->iounmap(vpdev, vdev->vr[index]);
 396         return ERR_PTR(err);
 397 }
 398
 399 static int vop_find_vqs(struct virtio_device *dev, unsigned nvqs,
 400                         struct virtqueue *vqs[],
 401                         vq_callback_t *callbacks[],
 402                         const char * const names[], const bool *ctx,
 403                         struct irq_affinity *desc)
 404 {
 405         struct _vop_vdev *vdev = to_vopvdev(dev);
 406         struct vop_device *vpdev = vdev->vpdev;
 407         struct mic_device_ctrl __iomem *dc = vdev->dc;
 408         int i, err, retry, queue_idx = 0;
 409
 410         /* We must have this many virtqueues. */
 411         if (nvqs > ioread8(&vdev->desc->num_vq))
 412                 return -ENOENT;
 413
 414         for (i = 0; i < nvqs; ++i) {
 415                 if (!names[i]) {
 416                         vqs[i] = NULL;
 417                         continue;
 418                 }
 419
 420                 dev_dbg(_vop_dev(vdev), "%s: %d: %s\n",
 421                         __func__, i, names[i]);
 422                 vqs[i] = vop_find_vq(dev, queue_idx++, callbacks[i], names[i],
 423                                      ctx ? ctx[i] : false);
 424                 if (IS_ERR(vqs[i])) {
 425                         err = PTR_ERR(vqs[i]);
 426                         goto error;
 427                 }
 428         }
 429
 430         iowrite8(1, &dc->used_address_updated);
 431         /*
 432          * Send an interrupt to the host to inform it that used
 433          * rings have been re-assigned.
 434          */
 435         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 436         for (retry = 100; --retry;) {
 437                 if (!ioread8(&dc->used_address_updated))
 438                         break;
 439                 msleep(100);
 440         };
 441
 442         dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
 443         if (!retry) {
 444                 err = -ENODEV;
 445                 goto error;
 446         }
 447
 448         return 0;
 449 error:
 450         vop_del_vqs(dev);
 451         return err;
 452 }
 453
 454 /*
 455  * The config ops structure as defined by virtio config
 456  */
 457 static struct virtio_config_ops vop_vq_config_ops = {
 458         .get_features = vop_get_features,
 459         .finalize_features = vop_finalize_features,
 460         .get = vop_get,
 461         .set = vop_set,
 462         .get_status = vop_get_status,
 463         .set_status = vop_set_status,
 464         .reset = vop_reset,
 465         .find_vqs = vop_find_vqs,
 466         .del_vqs = vop_del_vqs,
 467 };
 468
 469 static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
 470 {
 471         struct _vop_vdev *vdev = data;
 472         struct vop_device *vpdev = vdev->vpdev;
 473         struct virtqueue *vq;
 474
 475         vpdev->hw_ops->ack_interrupt(vpdev, vdev->h2c_vdev_db);
 476         list_for_each_entry(vq, &vdev->vdev.vqs, list)
 477                 vring_interrupt(0, vq);
 478
 479         return IRQ_HANDLED;
 480 }
 481
 482 static void vop_virtio_release_dev(struct device *_d)
 483 {
 484         struct virtio_device *vdev =
 485                         container_of(_d, struct virtio_device, dev);
 486         struct _vop_vdev *vop_vdev =
 487                         container_of(vdev, struct _vop_vdev, vdev);
 488
 489         kfree(vop_vdev);
 490 }
 491
 492 /*
 493  * adds a new device and register it with virtio
 494  * appropriate drivers are loaded by the device model
 495  */
 496 static int _vop_add_device(struct mic_device_desc __iomem *d,
 497                            unsigned int offset, struct vop_device *vpdev,
 498                            int dnode)
 499 {
 500         struct _vop_vdev *vdev, *reg_dev = NULL;
 501         int ret;
 502         u8 type = ioread8(&d->type);
 503
 504         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 505         if (!vdev)
 506                 return -ENOMEM;
 507
 508         vdev->vpdev = vpdev;
 509         vdev->vdev.dev.parent = &vpdev->dev;
 510         vdev->vdev.dev.release = vop_virtio_release_dev;
 511         vdev->vdev.id.device = type;
 512         vdev->vdev.config = &vop_vq_config_ops;
 513         vdev->desc = d;
 514         vdev->dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 515         vdev->dnode = dnode;
 516         vdev->vdev.priv = (void *)(u64)dnode;
 517         init_completion(&vdev->reset_done);
 518
 519         vdev->h2c_vdev_db = vpdev->hw_ops->next_db(vpdev);
 520         vdev->virtio_cookie = vpdev->hw_ops->request_irq(vpdev,
 521                         vop_virtio_intr_handler, "virtio intr",
 522                         vdev, vdev->h2c_vdev_db);
 523         if (IS_ERR(vdev->virtio_cookie)) {
 524                 ret = PTR_ERR(vdev->virtio_cookie);
 525                 goto kfree;
 526         }
 527         iowrite8((u8)vdev->h2c_vdev_db, &vdev->dc->h2c_vdev_db);
 528         vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
 529
 530         ret = register_virtio_device(&vdev->vdev);
 531         reg_dev = vdev;
 532         if (ret) {
 533                 dev_err(_vop_dev(vdev),
 534                         "Failed to register vop device %u type %u\n",
 535                         offset, type);
 536                 goto free_irq;
 537         }
 538         writeq((u64)vdev, &vdev->dc->vdev);
 539         dev_dbg(_vop_dev(vdev), "%s: registered vop device %u type %u vdev %p\n",
 540                 __func__, offset, type, vdev);
 541
 542         return 0;
 543
 544 free_irq:
 545         vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 546 kfree:
 547         if (reg_dev)
 548                 put_device(&vdev->vdev.dev);
 549         else
 550                 kfree(vdev);
 551         return ret;
 552 }
 553
 554 /*
 555  * match for a vop device with a specific desc pointer
 556  */
 557 static int vop_match_desc(struct device *dev, void *data)
 558 {
 559         struct virtio_device *_dev = dev_to_virtio(dev);
 560         struct _vop_vdev *vdev = to_vopvdev(_dev);
 561
 562         return vdev->desc == (void __iomem *)data;
 563 }
 564
 565 static void _vop_handle_config_change(struct mic_device_desc __iomem *d,
 566                                       unsigned int offset,
 567                                       struct vop_device *vpdev)
 568 {
 569         struct mic_device_ctrl __iomem *dc
 570                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 571         struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
 572
 573         if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED)
 574                 return;
 575
 576         dev_dbg(&vpdev->dev, "%s %d\n", __func__, __LINE__);
 577         virtio_config_changed(&vdev->vdev);
 578         iowrite8(1, &dc->guest_ack);
 579 }
 580
 581 /*
 582  * removes a virtio device if a hot remove event has been
 583  * requested by the host.
 584  */
 585 static int _vop_remove_device(struct mic_device_desc __iomem *d,
 586                               unsigned int offset, struct vop_device *vpdev)
 587 {
 588         struct mic_device_ctrl __iomem *dc
 589                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 590         struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
 591         u8 status;
 592         int ret = -1;
 593
 594         if (ioread8(&dc->config_change) == MIC_VIRTIO_PARAM_DEV_REMOVE) {
 595                 struct device *dev = get_device(&vdev->vdev.dev);
 596
 597                 dev_dbg(&vpdev->dev,
 598                         "%s %d config_change %d type %d vdev %p\n",
 599                         __func__, __LINE__,
 600                         ioread8(&dc->config_change), ioread8(&d->type), vdev);
 601                 status = ioread8(&d->status);
 602                 reinit_completion(&vdev->reset_done);
 603                 unregister_virtio_device(&vdev->vdev);
 604                 vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 605                 iowrite8(-1, &dc->h2c_vdev_db);
 606                 if (status & VIRTIO_CONFIG_S_DRIVER_OK)
 607                         wait_for_completion(&vdev->reset_done);
 608                 put_device(dev);
 609                 iowrite8(1, &dc->guest_ack);
 610                 dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
 611                         __func__, __LINE__, ioread8(&dc->guest_ack));
 612                 iowrite8(-1, &d->type);
 613                 ret = 0;
 614         }
 615         return ret;
 616 }
 617
 618 #define REMOVE_DEVICES true
 619
 620 static void _vop_scan_devices(void __iomem *dp, struct vop_device *vpdev,
 621                               bool remove, int dnode)
 622 {
 623         s8 type;
 624         unsigned int i;
 625         struct mic_device_desc __iomem *d;
 626         struct mic_device_ctrl __iomem *dc;
 627         struct device *dev;
 628         int ret;
 629
 630         for (i = sizeof(struct mic_bootparam);
 631                         i < MIC_DP_SIZE; i += _vop_total_desc_size(d)) {
 632                 d = dp + i;
 633                 dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 634                 /*
 635                  * This read barrier is paired with the corresponding write
 636                  * barrier on the host which is inserted before adding or
 637                  * removing a virtio device descriptor, by updating the type.
 638                  */
 639                 rmb();
 640                 type = ioread8(&d->type);
 641
 642                 /* end of list */
 643                 if (type == 0)
 644                         break;
 645
 646                 if (type == -1)
 647                         continue;
 648
 649                 /* device already exists */
 650                 dev = device_find_child(&vpdev->dev, (void __force *)d,
 651                                         vop_match_desc);
 652                 if (dev) {
 653                         if (remove)
 654                                 iowrite8(MIC_VIRTIO_PARAM_DEV_REMOVE,
 655                                          &dc->config_change);
 656                         put_device(dev);
 657                         _vop_handle_config_change(d, i, vpdev);
 658                         ret = _vop_remove_device(d, i, vpdev);
 659                         if (remove) {
 660                                 iowrite8(0, &dc->config_change);
 661                                 iowrite8(0, &dc->guest_ack);
 662                         }
 663                         continue;
 664                 }
 665
 666                 /* new device */
 667                 dev_dbg(&vpdev->dev, "%s %d Adding new virtio device %p\n",
 668                         __func__, __LINE__, d);
 669                 if (!remove)
 670                         _vop_add_device(d, i, vpdev, dnode);
 671         }
 672 }
 673
 674 static void vop_scan_devices(struct vop_info *vi,
 675                              struct vop_device *vpdev, bool remove)
 676 {
 677         void __iomem *dp = vpdev->hw_ops->get_remote_dp(vpdev);
 678
 679         if (!dp)
 680                 return;
 681         mutex_lock(&vi->vop_mutex);
 682         _vop_scan_devices(dp, vpdev, remove, vpdev->dnode);
 683         mutex_unlock(&vi->vop_mutex);
 684 }
 685
 686 /*
 687  * vop_hotplug_device tries to find changes in the device page.
 688  */
 689 static void vop_hotplug_devices(struct work_struct *work)
 690 {
 691         struct vop_info *vi = container_of(work, struct vop_info,
 692                                              hotplug_work);
 693
 694         vop_scan_devices(vi, vi->vpdev, !REMOVE_DEVICES);
 695 }
 696
 697 /*
 698  * Interrupt handler for hot plug/config changes etc.
 699  */
 700 static irqreturn_t vop_extint_handler(int irq, void *data)
 701 {
 702         struct vop_info *vi = data;
 703         struct mic_bootparam __iomem *bp;
 704         struct vop_device *vpdev = vi->vpdev;
 705
 706         bp = vpdev->hw_ops->get_remote_dp(vpdev);
 707         dev_dbg(&vpdev->dev, "%s %d hotplug work\n",
 708                 __func__, __LINE__);
 709         vpdev->hw_ops->ack_interrupt(vpdev, ioread8(&bp->h2c_config_db));
 710         schedule_work(&vi->hotplug_work);
 711         return IRQ_HANDLED;
 712 }
 713
 714 static int vop_driver_probe(struct vop_device *vpdev)
 715 {
 716         struct vop_info *vi;
 717         int rc;
 718
 719         vi = kzalloc(sizeof(*vi), GFP_KERNEL);
 720         if (!vi) {
 721                 rc = -ENOMEM;
 722                 goto exit;
 723         }
 724         dev_set_drvdata(&vpdev->dev, vi);
 725         vi->vpdev = vpdev;
 726
 727         mutex_init(&vi->vop_mutex);
 728         INIT_WORK(&vi->hotplug_work, vop_hotplug_devices);
 729         if (vpdev->dnode) {
 730                 rc = vop_host_init(vi);
 731                 if (rc < 0)
 732                         goto free;
 733         } else {
 734                 struct mic_bootparam __iomem *bootparam;
 735
 736                 vop_scan_devices(vi, vpdev, !REMOVE_DEVICES);
 737
 738                 vi->h2c_config_db = vpdev->hw_ops->next_db(vpdev);
 739                 vi->cookie = vpdev->hw_ops->request_irq(vpdev,
 740                                                         vop_extint_handler,
 741                                                         "virtio_config_intr",
 742                                                         vi, vi->h2c_config_db);
 743                 if (IS_ERR(vi->cookie)) {
 744                         rc = PTR_ERR(vi->cookie);
 745                         goto free;
 746                 }
 747                 bootparam = vpdev->hw_ops->get_remote_dp(vpdev);
 748                 iowrite8(vi->h2c_config_db, &bootparam->h2c_config_db);
 749         }
 750         vop_init_debugfs(vi);
 751         return 0;
 752 free:
 753         kfree(vi);
 754 exit:
 755         return rc;
 756 }
 757
 758 static void vop_driver_remove(struct vop_device *vpdev)
 759 {
 760         struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
 761
 762         if (vpdev->dnode) {
 763                 vop_host_uninit(vi);
 764         } else {
 765                 struct mic_bootparam __iomem *bootparam =
 766                         vpdev->hw_ops->get_remote_dp(vpdev);
 767                 if (bootparam)
 768                         iowrite8(-1, &bootparam->h2c_config_db);
 769                 vpdev->hw_ops->free_irq(vpdev, vi->cookie, vi);
 770                 flush_work(&vi->hotplug_work);
 771                 vop_scan_devices(vi, vpdev, REMOVE_DEVICES);
 772         }
 773         vop_exit_debugfs(vi);
 774         kfree(vi);
 775 }
 776
 777 static struct vop_device_id id_table[] = {
 778         { VOP_DEV_TRNSP, VOP_DEV_ANY_ID },
 779         { 0 },
 780 };
 781
 782 static struct vop_driver vop_driver = {
 783         .driver.name =  KBUILD_MODNAME,
 784         .driver.owner = THIS_MODULE,
 785         .id_table = id_table,
 786         .probe = vop_driver_probe,
 787         .remove = vop_driver_remove,
 788 };
 789
 790 module_vop_driver(vop_driver);
 791
 792 MODULE_DEVICE_TABLE(mbus, id_table);
 793 MODULE_AUTHOR("Intel Corporation");
 794 MODULE_DESCRIPTION("Intel(R) Virtio Over PCIe (VOP) driver");
 795 MODULE_LICENSE("GPL v2");