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: Buffer for used
  51  * @used_size: Size of the used buffer
  52  * @reset_done: Track whether VOP reset is complete
  53  * @virtio_cookie: Cookie returned upon requesting a interrupt
  54  * @c2h_vdev_db: The doorbell used by the guest to interrupt the host
  55  * @h2c_vdev_db: The doorbell used by the host to interrupt the guest
  56  * @dnode: The destination node
  57  */
  58 struct _vop_vdev {
  59         struct virtio_device vdev;
  60         struct mic_device_desc __iomem *desc;
  61         struct mic_device_ctrl __iomem *dc;
  62         struct vop_device *vpdev;
  63         void __iomem *vr[VOP_MAX_VRINGS];
  64         dma_addr_t used[VOP_MAX_VRINGS];
  65         int used_size[VOP_MAX_VRINGS];
  66         struct completion reset_done;
  67         struct mic_irq *virtio_cookie;
  68         int c2h_vdev_db;
  69         int h2c_vdev_db;
  70         int dnode;
  71 };
  72
  73 #define to_vopvdev(vd) container_of(vd, struct _vop_vdev, vdev)
  74
  75 #define _vop_aligned_desc_size(d) __mic_align(_vop_desc_size(d), 8)
  76
  77 /* Helper API to obtain the parent of the virtio device */
  78 static inline struct device *_vop_dev(struct _vop_vdev *vdev)
  79 {
  80         return vdev->vdev.dev.parent;
  81 }
  82
  83 static inline unsigned _vop_desc_size(struct mic_device_desc __iomem *desc)
  84 {
  85         return sizeof(*desc)
  86                 + ioread8(&desc->num_vq) * sizeof(struct mic_vqconfig)
  87                 + ioread8(&desc->feature_len) * 2
  88                 + ioread8(&desc->config_len);
  89 }
  90
  91 static inline struct mic_vqconfig __iomem *
  92 _vop_vq_config(struct mic_device_desc __iomem *desc)
  93 {
  94         return (struct mic_vqconfig __iomem *)(desc + 1);
  95 }
  96
  97 static inline u8 __iomem *
  98 _vop_vq_features(struct mic_device_desc __iomem *desc)
  99 {
 100         return (u8 __iomem *)(_vop_vq_config(desc) + ioread8(&desc->num_vq));
 101 }
 102
 103 static inline u8 __iomem *
 104 _vop_vq_configspace(struct mic_device_desc __iomem *desc)
 105 {
 106         return _vop_vq_features(desc) + ioread8(&desc->feature_len) * 2;
 107 }
 108
 109 static inline unsigned
 110 _vop_total_desc_size(struct mic_device_desc __iomem *desc)
 111 {
 112         return _vop_aligned_desc_size(desc) + sizeof(struct mic_device_ctrl);
 113 }
 114
 115 /* This gets the device's feature bits. */
 116 static u64 vop_get_features(struct virtio_device *vdev)
 117 {
 118         unsigned int i, bits;
 119         u32 features = 0;
 120         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 121         u8 __iomem *in_features = _vop_vq_features(desc);
 122         int feature_len = ioread8(&desc->feature_len);
 123
 124         bits = min_t(unsigned, feature_len, sizeof(vdev->features)) * 8;
 125         for (i = 0; i < bits; i++)
 126                 if (ioread8(&in_features[i / 8]) & (BIT(i % 8)))
 127                         features |= BIT(i);
 128
 129         return features;
 130 }
 131
 132 static int vop_finalize_features(struct virtio_device *vdev)
 133 {
 134         unsigned int i, bits;
 135         struct mic_device_desc __iomem *desc = to_vopvdev(vdev)->desc;
 136         u8 feature_len = ioread8(&desc->feature_len);
 137         /* Second half of bitmap is features we accept. */
 138         u8 __iomem *out_features =
 139                 _vop_vq_features(desc) + feature_len;
 140
 141         /* Give virtio_ring a chance to accept features. */
 142         vring_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 vring *vr = (struct vring *)(vq + 1);
 251         struct vop_device *vpdev = vdev->vpdev;
 252
 253         dma_unmap_single(&vpdev->dev, vdev->used[n],
 254                          vdev->used_size[n], DMA_BIDIRECTIONAL);
 255         free_pages((unsigned long)vr->used, get_order(vdev->used_size[n]));
 256         vring_del_virtqueue(vq);
 257         vpdev->hw_ops->iounmap(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 /*
 274  * This routine will assign vring's allocated in host/io memory. Code in
 275  * virtio_ring.c however continues to access this io memory as if it were local
 276  * memory without io accessors.
 277  */
 278 static struct virtqueue *vop_find_vq(struct virtio_device *dev,
 279                                      unsigned index,
 280                                      void (*callback)(struct virtqueue *vq),
 281                                      const char *name, bool ctx)
 282 {
 283         struct _vop_vdev *vdev = to_vopvdev(dev);
 284         struct vop_device *vpdev = vdev->vpdev;
 285         struct mic_vqconfig __iomem *vqconfig;
 286         struct mic_vqconfig config;
 287         struct virtqueue *vq;
 288         void __iomem *va;
 289         struct _mic_vring_info __iomem *info;
 290         void *used;
 291         int vr_size, _vr_size, err, magic;
 292         struct vring *vr;
 293         u8 type = ioread8(&vdev->desc->type);
 294
 295         if (index >= ioread8(&vdev->desc->num_vq))
 296                 return ERR_PTR(-ENOENT);
 297
 298         if (!name)
 299                 return ERR_PTR(-ENOENT);
 300
 301         /* First assign the vring's allocated in host memory */
 302         vqconfig = _vop_vq_config(vdev->desc) + index;
 303         memcpy_fromio(&config, vqconfig, sizeof(config));
 304         _vr_size = vring_size(le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN);
 305         vr_size = PAGE_ALIGN(_vr_size + sizeof(struct _mic_vring_info));
 306         va = vpdev->hw_ops->ioremap(vpdev, le64_to_cpu(config.address),
 307                         vr_size);
 308         if (!va)
 309                 return ERR_PTR(-ENOMEM);
 310         vdev->vr[index] = va;
 311         memset_io(va, 0x0, _vr_size);
 312         vq = vring_new_virtqueue(
 313                                 index,
 314                                 le16_to_cpu(config.num), MIC_VIRTIO_RING_ALIGN,
 315                                 dev,
 316                                 false,
 317                                 ctx,
 318                                 (void __force *)va, vop_notify, callback, name);
 319         if (!vq) {
 320                 err = -ENOMEM;
 321                 goto unmap;
 322         }
 323         info = va + _vr_size;
 324         magic = ioread32(&info->magic);
 325
 326         if (WARN(magic != MIC_MAGIC + type + index, "magic mismatch")) {
 327                 err = -EIO;
 328                 goto unmap;
 329         }
 330
 331         /* Allocate and reassign used ring now */
 332         vdev->used_size[index] = PAGE_ALIGN(sizeof(__u16) * 3 +
 333                                              sizeof(struct vring_used_elem) *
 334                                              le16_to_cpu(config.num));
 335         used = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
 336                                         get_order(vdev->used_size[index]));
 337         if (!used) {
 338                 err = -ENOMEM;
 339                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 340                         __func__, __LINE__, err);
 341                 goto del_vq;
 342         }
 343         vdev->used[index] = dma_map_single(&vpdev->dev, used,
 344                                             vdev->used_size[index],
 345                                             DMA_BIDIRECTIONAL);
 346         if (dma_mapping_error(&vpdev->dev, vdev->used[index])) {
 347                 err = -ENOMEM;
 348                 dev_err(_vop_dev(vdev), "%s %d err %d\n",
 349                         __func__, __LINE__, err);
 350                 goto free_used;
 351         }
 352         writeq(vdev->used[index], &vqconfig->used_address);
 353         /*
 354          * To reassign the used ring here we are directly accessing
 355          * struct vring_virtqueue which is a private data structure
 356          * in virtio_ring.c. At the minimum, a BUILD_BUG_ON() in
 357          * vring_new_virtqueue() would ensure that
 358          *  (&vq->vring == (struct vring *) (&vq->vq + 1));
 359          */
 360         vr = (struct vring *)(vq + 1);
 361         vr->used = used;
 362
 363         vq->priv = vdev;
 364         return vq;
 365 free_used:
 366         free_pages((unsigned long)used,
 367                    get_order(vdev->used_size[index]));
 368 del_vq:
 369         vring_del_virtqueue(vq);
 370 unmap:
 371         vpdev->hw_ops->iounmap(vpdev, vdev->vr[index]);
 372         return ERR_PTR(err);
 373 }
 374
 375 static int vop_find_vqs(struct virtio_device *dev, unsigned nvqs,
 376                         struct virtqueue *vqs[],
 377                         vq_callback_t *callbacks[],
 378                         const char * const names[], const bool *ctx,
 379                         struct irq_affinity *desc)
 380 {
 381         struct _vop_vdev *vdev = to_vopvdev(dev);
 382         struct vop_device *vpdev = vdev->vpdev;
 383         struct mic_device_ctrl __iomem *dc = vdev->dc;
 384         int i, err, retry;
 385
 386         /* We must have this many virtqueues. */
 387         if (nvqs > ioread8(&vdev->desc->num_vq))
 388                 return -ENOENT;
 389
 390         for (i = 0; i < nvqs; ++i) {
 391                 dev_dbg(_vop_dev(vdev), "%s: %d: %s\n",
 392                         __func__, i, names[i]);
 393                 vqs[i] = vop_find_vq(dev, i, callbacks[i], names[i],
 394                                      ctx ? ctx[i] : false);
 395                 if (IS_ERR(vqs[i])) {
 396                         err = PTR_ERR(vqs[i]);
 397                         goto error;
 398                 }
 399         }
 400
 401         iowrite8(1, &dc->used_address_updated);
 402         /*
 403          * Send an interrupt to the host to inform it that used
 404          * rings have been re-assigned.
 405          */
 406         vpdev->hw_ops->send_intr(vpdev, vdev->c2h_vdev_db);
 407         for (retry = 100; --retry;) {
 408                 if (!ioread8(&dc->used_address_updated))
 409                         break;
 410                 msleep(100);
 411         };
 412
 413         dev_dbg(_vop_dev(vdev), "%s: retry: %d\n", __func__, retry);
 414         if (!retry) {
 415                 err = -ENODEV;
 416                 goto error;
 417         }
 418
 419         return 0;
 420 error:
 421         vop_del_vqs(dev);
 422         return err;
 423 }
 424
 425 /*
 426  * The config ops structure as defined by virtio config
 427  */
 428 static struct virtio_config_ops vop_vq_config_ops = {
 429         .get_features = vop_get_features,
 430         .finalize_features = vop_finalize_features,
 431         .get = vop_get,
 432         .set = vop_set,
 433         .get_status = vop_get_status,
 434         .set_status = vop_set_status,
 435         .reset = vop_reset,
 436         .find_vqs = vop_find_vqs,
 437         .del_vqs = vop_del_vqs,
 438 };
 439
 440 static irqreturn_t vop_virtio_intr_handler(int irq, void *data)
 441 {
 442         struct _vop_vdev *vdev = data;
 443         struct vop_device *vpdev = vdev->vpdev;
 444         struct virtqueue *vq;
 445
 446         vpdev->hw_ops->ack_interrupt(vpdev, vdev->h2c_vdev_db);
 447         list_for_each_entry(vq, &vdev->vdev.vqs, list)
 448                 vring_interrupt(0, vq);
 449
 450         return IRQ_HANDLED;
 451 }
 452
 453 static void vop_virtio_release_dev(struct device *_d)
 454 {
 455         struct virtio_device *vdev =
 456                         container_of(_d, struct virtio_device, dev);
 457         struct _vop_vdev *vop_vdev =
 458                         container_of(vdev, struct _vop_vdev, vdev);
 459
 460         kfree(vop_vdev);
 461 }
 462
 463 /*
 464  * adds a new device and register it with virtio
 465  * appropriate drivers are loaded by the device model
 466  */
 467 static int _vop_add_device(struct mic_device_desc __iomem *d,
 468                            unsigned int offset, struct vop_device *vpdev,
 469                            int dnode)
 470 {
 471         struct _vop_vdev *vdev, *reg_dev = NULL;
 472         int ret;
 473         u8 type = ioread8(&d->type);
 474
 475         vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
 476         if (!vdev)
 477                 return -ENOMEM;
 478
 479         vdev->vpdev = vpdev;
 480         vdev->vdev.dev.parent = &vpdev->dev;
 481         vdev->vdev.dev.release = vop_virtio_release_dev;
 482         vdev->vdev.id.device = type;
 483         vdev->vdev.config = &vop_vq_config_ops;
 484         vdev->desc = d;
 485         vdev->dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 486         vdev->dnode = dnode;
 487         vdev->vdev.priv = (void *)(u64)dnode;
 488         init_completion(&vdev->reset_done);
 489
 490         vdev->h2c_vdev_db = vpdev->hw_ops->next_db(vpdev);
 491         vdev->virtio_cookie = vpdev->hw_ops->request_irq(vpdev,
 492                         vop_virtio_intr_handler, "virtio intr",
 493                         vdev, vdev->h2c_vdev_db);
 494         if (IS_ERR(vdev->virtio_cookie)) {
 495                 ret = PTR_ERR(vdev->virtio_cookie);
 496                 goto kfree;
 497         }
 498         iowrite8((u8)vdev->h2c_vdev_db, &vdev->dc->h2c_vdev_db);
 499         vdev->c2h_vdev_db = ioread8(&vdev->dc->c2h_vdev_db);
 500
 501         ret = register_virtio_device(&vdev->vdev);
 502         reg_dev = vdev;
 503         if (ret) {
 504                 dev_err(_vop_dev(vdev),
 505                         "Failed to register vop device %u type %u\n",
 506                         offset, type);
 507                 goto free_irq;
 508         }
 509         writeq((u64)vdev, &vdev->dc->vdev);
 510         dev_dbg(_vop_dev(vdev), "%s: registered vop device %u type %u vdev %p\n",
 511                 __func__, offset, type, vdev);
 512
 513         return 0;
 514
 515 free_irq:
 516         vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 517 kfree:
 518         if (reg_dev)
 519                 put_device(&vdev->vdev.dev);
 520         else
 521                 kfree(vdev);
 522         return ret;
 523 }
 524
 525 /*
 526  * match for a vop device with a specific desc pointer
 527  */
 528 static int vop_match_desc(struct device *dev, void *data)
 529 {
 530         struct virtio_device *_dev = dev_to_virtio(dev);
 531         struct _vop_vdev *vdev = to_vopvdev(_dev);
 532
 533         return vdev->desc == (void __iomem *)data;
 534 }
 535
 536 static void _vop_handle_config_change(struct mic_device_desc __iomem *d,
 537                                       unsigned int offset,
 538                                       struct vop_device *vpdev)
 539 {
 540         struct mic_device_ctrl __iomem *dc
 541                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 542         struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
 543
 544         if (ioread8(&dc->config_change) != MIC_VIRTIO_PARAM_CONFIG_CHANGED)
 545                 return;
 546
 547         dev_dbg(&vpdev->dev, "%s %d\n", __func__, __LINE__);
 548         virtio_config_changed(&vdev->vdev);
 549         iowrite8(1, &dc->guest_ack);
 550 }
 551
 552 /*
 553  * removes a virtio device if a hot remove event has been
 554  * requested by the host.
 555  */
 556 static int _vop_remove_device(struct mic_device_desc __iomem *d,
 557                               unsigned int offset, struct vop_device *vpdev)
 558 {
 559         struct mic_device_ctrl __iomem *dc
 560                 = (void __iomem *)d + _vop_aligned_desc_size(d);
 561         struct _vop_vdev *vdev = (struct _vop_vdev *)readq(&dc->vdev);
 562         u8 status;
 563         int ret = -1;
 564
 565         if (ioread8(&dc->config_change) == MIC_VIRTIO_PARAM_DEV_REMOVE) {
 566                 dev_dbg(&vpdev->dev,
 567                         "%s %d config_change %d type %d vdev %p\n",
 568                         __func__, __LINE__,
 569                         ioread8(&dc->config_change), ioread8(&d->type), vdev);
 570                 status = ioread8(&d->status);
 571                 reinit_completion(&vdev->reset_done);
 572                 unregister_virtio_device(&vdev->vdev);
 573                 vpdev->hw_ops->free_irq(vpdev, vdev->virtio_cookie, vdev);
 574                 iowrite8(-1, &dc->h2c_vdev_db);
 575                 if (status & VIRTIO_CONFIG_S_DRIVER_OK)
 576                         wait_for_completion(&vdev->reset_done);
 577                 put_device(&vdev->vdev.dev);
 578                 iowrite8(1, &dc->guest_ack);
 579                 dev_dbg(&vpdev->dev, "%s %d guest_ack %d\n",
 580                         __func__, __LINE__, ioread8(&dc->guest_ack));
 581                 iowrite8(-1, &d->type);
 582                 ret = 0;
 583         }
 584         return ret;
 585 }
 586
 587 #define REMOVE_DEVICES true
 588
 589 static void _vop_scan_devices(void __iomem *dp, struct vop_device *vpdev,
 590                               bool remove, int dnode)
 591 {
 592         s8 type;
 593         unsigned int i;
 594         struct mic_device_desc __iomem *d;
 595         struct mic_device_ctrl __iomem *dc;
 596         struct device *dev;
 597         int ret;
 598
 599         for (i = sizeof(struct mic_bootparam);
 600                         i < MIC_DP_SIZE; i += _vop_total_desc_size(d)) {
 601                 d = dp + i;
 602                 dc = (void __iomem *)d + _vop_aligned_desc_size(d);
 603                 /*
 604                  * This read barrier is paired with the corresponding write
 605                  * barrier on the host which is inserted before adding or
 606                  * removing a virtio device descriptor, by updating the type.
 607                  */
 608                 rmb();
 609                 type = ioread8(&d->type);
 610
 611                 /* end of list */
 612                 if (type == 0)
 613                         break;
 614
 615                 if (type == -1)
 616                         continue;
 617
 618                 /* device already exists */
 619                 dev = device_find_child(&vpdev->dev, (void __force *)d,
 620                                         vop_match_desc);
 621                 if (dev) {
 622                         if (remove)
 623                                 iowrite8(MIC_VIRTIO_PARAM_DEV_REMOVE,
 624                                          &dc->config_change);
 625                         put_device(dev);
 626                         _vop_handle_config_change(d, i, vpdev);
 627                         ret = _vop_remove_device(d, i, vpdev);
 628                         if (remove) {
 629                                 iowrite8(0, &dc->config_change);
 630                                 iowrite8(0, &dc->guest_ack);
 631                         }
 632                         continue;
 633                 }
 634
 635                 /* new device */
 636                 dev_dbg(&vpdev->dev, "%s %d Adding new virtio device %p\n",
 637                         __func__, __LINE__, d);
 638                 if (!remove)
 639                         _vop_add_device(d, i, vpdev, dnode);
 640         }
 641 }
 642
 643 static void vop_scan_devices(struct vop_info *vi,
 644                              struct vop_device *vpdev, bool remove)
 645 {
 646         void __iomem *dp = vpdev->hw_ops->get_remote_dp(vpdev);
 647
 648         if (!dp)
 649                 return;
 650         mutex_lock(&vi->vop_mutex);
 651         _vop_scan_devices(dp, vpdev, remove, vpdev->dnode);
 652         mutex_unlock(&vi->vop_mutex);
 653 }
 654
 655 /*
 656  * vop_hotplug_device tries to find changes in the device page.
 657  */
 658 static void vop_hotplug_devices(struct work_struct *work)
 659 {
 660         struct vop_info *vi = container_of(work, struct vop_info,
 661                                              hotplug_work);
 662
 663         vop_scan_devices(vi, vi->vpdev, !REMOVE_DEVICES);
 664 }
 665
 666 /*
 667  * Interrupt handler for hot plug/config changes etc.
 668  */
 669 static irqreturn_t vop_extint_handler(int irq, void *data)
 670 {
 671         struct vop_info *vi = data;
 672         struct mic_bootparam __iomem *bp;
 673         struct vop_device *vpdev = vi->vpdev;
 674
 675         bp = vpdev->hw_ops->get_remote_dp(vpdev);
 676         dev_dbg(&vpdev->dev, "%s %d hotplug work\n",
 677                 __func__, __LINE__);
 678         vpdev->hw_ops->ack_interrupt(vpdev, ioread8(&bp->h2c_config_db));
 679         schedule_work(&vi->hotplug_work);
 680         return IRQ_HANDLED;
 681 }
 682
 683 static int vop_driver_probe(struct vop_device *vpdev)
 684 {
 685         struct vop_info *vi;
 686         int rc;
 687
 688         vi = kzalloc(sizeof(*vi), GFP_KERNEL);
 689         if (!vi) {
 690                 rc = -ENOMEM;
 691                 goto exit;
 692         }
 693         dev_set_drvdata(&vpdev->dev, vi);
 694         vi->vpdev = vpdev;
 695
 696         mutex_init(&vi->vop_mutex);
 697         INIT_WORK(&vi->hotplug_work, vop_hotplug_devices);
 698         if (vpdev->dnode) {
 699                 rc = vop_host_init(vi);
 700                 if (rc < 0)
 701                         goto free;
 702         } else {
 703                 struct mic_bootparam __iomem *bootparam;
 704
 705                 vop_scan_devices(vi, vpdev, !REMOVE_DEVICES);
 706
 707                 vi->h2c_config_db = vpdev->hw_ops->next_db(vpdev);
 708                 vi->cookie = vpdev->hw_ops->request_irq(vpdev,
 709                                                         vop_extint_handler,
 710                                                         "virtio_config_intr",
 711                                                         vi, vi->h2c_config_db);
 712                 if (IS_ERR(vi->cookie)) {
 713                         rc = PTR_ERR(vi->cookie);
 714                         goto free;
 715                 }
 716                 bootparam = vpdev->hw_ops->get_remote_dp(vpdev);
 717                 iowrite8(vi->h2c_config_db, &bootparam->h2c_config_db);
 718         }
 719         vop_init_debugfs(vi);
 720         return 0;
 721 free:
 722         kfree(vi);
 723 exit:
 724         return rc;
 725 }
 726
 727 static void vop_driver_remove(struct vop_device *vpdev)
 728 {
 729         struct vop_info *vi = dev_get_drvdata(&vpdev->dev);
 730
 731         if (vpdev->dnode) {
 732                 vop_host_uninit(vi);
 733         } else {
 734                 struct mic_bootparam __iomem *bootparam =
 735                         vpdev->hw_ops->get_remote_dp(vpdev);
 736                 if (bootparam)
 737                         iowrite8(-1, &bootparam->h2c_config_db);
 738                 vpdev->hw_ops->free_irq(vpdev, vi->cookie, vi);
 739                 flush_work(&vi->hotplug_work);
 740                 vop_scan_devices(vi, vpdev, REMOVE_DEVICES);
 741         }
 742         vop_exit_debugfs(vi);
 743         kfree(vi);
 744 }
 745
 746 static struct vop_device_id id_table[] = {
 747         { VOP_DEV_TRNSP, VOP_DEV_ANY_ID },
 748         { 0 },
 749 };
 750
 751 static struct vop_driver vop_driver = {
 752         .driver.name =  KBUILD_MODNAME,
 753         .driver.owner = THIS_MODULE,
 754         .id_table = id_table,
 755         .probe = vop_driver_probe,
 756         .remove = vop_driver_remove,
 757 };
 758
 759 module_vop_driver(vop_driver);
 760
 761 MODULE_DEVICE_TABLE(mbus, id_table);
 762 MODULE_AUTHOR("Intel Corporation");
 763 MODULE_DESCRIPTION("Intel(R) Virtio Over PCIe (VOP) driver");
 764 MODULE_LICENSE("GPL v2");