drivers/visorbus/visorbus_main.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright � 2010 - 2015 UNISYS CORPORATION
   4  * All rights reserved.
   5  */
   6
   7 #include <linux/ctype.h>
   8 #include <linux/debugfs.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/visorbus.h>
  12 #include <linux/uuid.h>
  13
  14 #include "visorbus_private.h"
  15
  16 static const guid_t visor_vbus_channel_guid = VISOR_VBUS_CHANNEL_GUID;
  17
  18 /* Display string that is guaranteed to be no longer the 99 characters */
  19 #define LINESIZE 99
  20 #define POLLJIFFIES_NORMALCHANNEL 10
  21
  22 /* stores whether bus_registration was successful */
  23 static bool initialized;
  24 static struct dentry *visorbus_debugfs_dir;
  25
  26 /*
  27  * DEVICE type attributes
  28  *
  29  * The modalias file will contain the guid of the device.
  30  */
  31 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
  32                              char *buf)
  33 {
  34         struct visor_device *vdev;
  35         const guid_t *guid;
  36
  37         vdev = to_visor_device(dev);
  38         guid = visorchannel_get_guid(vdev->visorchannel);
  39         return sprintf(buf, "visorbus:%pUl\n", guid);
  40 }
  41 static DEVICE_ATTR_RO(modalias);
  42
  43 static struct attribute *visorbus_dev_attrs[] = {
  44         &dev_attr_modalias.attr,
  45         NULL,
  46 };
  47
  48 ATTRIBUTE_GROUPS(visorbus_dev);
  49
  50 /* filled in with info about parent chipset driver when we register with it */
  51 static struct visor_vbus_deviceinfo chipset_driverinfo;
  52 /* filled in with info about this driver, wrt it servicing client busses */
  53 static struct visor_vbus_deviceinfo clientbus_driverinfo;
  54
  55 /* list of visor_device structs, linked via .list_all */
  56 static LIST_HEAD(list_all_bus_instances);
  57 /* list of visor_device structs, linked via .list_all */
  58 static LIST_HEAD(list_all_device_instances);
  59
  60 /*
  61  * Generic function useful for validating any type of channel when it is
  62  * received by the client that will be accessing the channel.
  63  * Note that <logCtx> is only needed for callers in the EFI environment, and
  64  * is used to pass the EFI_DIAG_CAPTURE_PROTOCOL needed to log messages.
  65  */
  66 int visor_check_channel(struct channel_header *ch, struct device *dev,
  67                         const guid_t *expected_guid, char *chname,
  68                         u64 expected_min_bytes, u32 expected_version,
  69                         u64 expected_signature)
  70 {
  71         if (!guid_is_null(expected_guid)) {
  72                 /* caller wants us to verify type GUID */
  73                 if (!guid_equal(&ch->chtype, expected_guid)) {
  74                         dev_err(dev, "Channel mismatch on channel=%s(%pUL) field=type expected=%pUL actual=%pUL\n",
  75                                 chname, expected_guid, expected_guid,
  76                                 &ch->chtype);
  77                         return 0;
  78                 }
  79         }
  80         /* verify channel size */
  81         if (expected_min_bytes > 0) {
  82                 if (ch->size < expected_min_bytes) {
  83                         dev_err(dev, "Channel mismatch on channel=%s(%pUL) field=size expected=0x%-8.8Lx actual=0x%-8.8Lx\n",
  84                                 chname, expected_guid,
  85                                 (unsigned long long)expected_min_bytes,
  86                                 ch->size);
  87                         return 0;
  88                 }
  89         }
  90         /* verify channel version */
  91         if (expected_version > 0) {
  92                 if (ch->version_id != expected_version) {
  93                         dev_err(dev, "Channel mismatch on channel=%s(%pUL) field=version expected=0x%-8.8lx actual=0x%-8.8x\n",
  94                                 chname, expected_guid,
  95                                 (unsigned long)expected_version,
  96                                 ch->version_id);
  97                         return 0;
  98                 }
  99         }
 100         /* verify channel signature */
 101         if (expected_signature > 0) {
 102                 if (ch->signature != expected_signature) {
 103                         dev_err(dev, "Channel mismatch on channel=%s(%pUL) field=signature expected=0x%-8.8Lx actual=0x%-8.8Lx\n",
 104                                 chname, expected_guid,  expected_signature,
 105                                 ch->signature);
 106                         return 0;
 107                 }
 108         }
 109         return 1;
 110 }
 111
 112 static int visorbus_uevent(struct device *xdev, struct kobj_uevent_env *env)
 113 {
 114         struct visor_device *dev;
 115         const guid_t *guid;
 116
 117         dev = to_visor_device(xdev);
 118         guid = visorchannel_get_guid(dev->visorchannel);
 119         return add_uevent_var(env, "MODALIAS=visorbus:%pUl", guid);
 120 }
 121
 122 /*
 123  * visorbus_match() - called automatically upon adding a visor_device
 124  *                    (device_add), or adding a visor_driver
 125  *                    (visorbus_register_visor_driver)
 126  * @xdev: struct device for the device being matched
 127  * @xdrv: struct device_driver for driver to match device against
 128  *
 129  * Return: 1 iff the provided driver can control the specified device
 130  */
 131 static int visorbus_match(struct device *xdev, struct device_driver *xdrv)
 132 {
 133         const guid_t *channel_type;
 134         int i;
 135         struct visor_device *dev;
 136         struct visor_driver *drv;
 137         struct visorchannel *chan;
 138
 139         dev = to_visor_device(xdev);
 140         channel_type = visorchannel_get_guid(dev->visorchannel);
 141         drv = to_visor_driver(xdrv);
 142         chan = dev->visorchannel;
 143         if (!drv->channel_types)
 144                 return 0;
 145         for (i = 0; !guid_is_null(&drv->channel_types[i].guid); i++)
 146                 if (guid_equal(&drv->channel_types[i].guid, channel_type) &&
 147                     visor_check_channel(visorchannel_get_header(chan),
 148                                         xdev,
 149                                         &drv->channel_types[i].guid,
 150                                         (char *)drv->channel_types[i].name,
 151                                         drv->channel_types[i].min_bytes,
 152                                         drv->channel_types[i].version,
 153                                         VISOR_CHANNEL_SIGNATURE))
 154                         return i + 1;
 155         return 0;
 156 }
 157
 158 /*
 159  * This describes the TYPE of bus.
 160  * (Don't confuse this with an INSTANCE of the bus.)
 161  */
 162 static struct bus_type visorbus_type = {
 163         .name = "visorbus",
 164         .match = visorbus_match,
 165         .uevent = visorbus_uevent,
 166         .dev_groups = visorbus_dev_groups,
 167 };
 168
 169 struct visor_busdev {
 170         u32 bus_no;
 171         u32 dev_no;
 172 };
 173
 174 static int match_visorbus_dev_by_id(struct device *dev, const void *data)
 175 {
 176         struct visor_device *vdev = to_visor_device(dev);
 177         const struct visor_busdev *id = data;
 178
 179         if (vdev->chipset_bus_no == id->bus_no &&
 180             vdev->chipset_dev_no == id->dev_no)
 181                 return 1;
 182         return 0;
 183 }
 184
 185 struct visor_device *visorbus_get_device_by_id(u32 bus_no, u32 dev_no,
 186                                                struct visor_device *from)
 187 {
 188         struct device *dev;
 189         struct device *dev_start = NULL;
 190         struct visor_busdev id = {
 191                 .bus_no = bus_no,
 192                 .dev_no = dev_no
 193         };
 194
 195         if (from)
 196                 dev_start = &from->device;
 197         dev = bus_find_device(&visorbus_type, dev_start, (void *)&id,
 198                               match_visorbus_dev_by_id);
 199         if (!dev)
 200                 return NULL;
 201         return to_visor_device(dev);
 202 }
 203
 204 /*
 205  * visorbus_release_busdevice() - called when device_unregister() is called for
 206  *                                the bus device instance, after all other tasks
 207  *                                involved with destroying the dev are complete
 208  * @xdev: struct device for the bus being released
 209  */
 210 static void visorbus_release_busdevice(struct device *xdev)
 211 {
 212         struct visor_device *dev = dev_get_drvdata(xdev);
 213
 214         debugfs_remove(dev->debugfs_bus_info);
 215         debugfs_remove_recursive(dev->debugfs_dir);
 216         visorchannel_destroy(dev->visorchannel);
 217         kfree(dev);
 218 }
 219
 220 /*
 221  * visorbus_release_device() - called when device_unregister() is called for
 222  *                             each child device instance
 223  * @xdev: struct device for the visor device being released
 224  */
 225 static void visorbus_release_device(struct device *xdev)
 226 {
 227         struct visor_device *dev = to_visor_device(xdev);
 228
 229         visorchannel_destroy(dev->visorchannel);
 230         kfree(dev);
 231 }
 232
 233 /*
 234  * BUS specific channel attributes to appear under
 235  * /sys/bus/visorbus<x>/dev<y>/channel
 236  */
 237
 238 static ssize_t physaddr_show(struct device *dev, struct device_attribute *attr,
 239                              char *buf)
 240 {
 241         struct visor_device *vdev = to_visor_device(dev);
 242
 243         return sprintf(buf, "0x%llx\n",
 244                        visorchannel_get_physaddr(vdev->visorchannel));
 245 }
 246 static DEVICE_ATTR_RO(physaddr);
 247
 248 static ssize_t nbytes_show(struct device *dev, struct device_attribute *attr,
 249                            char *buf)
 250 {
 251         struct visor_device *vdev = to_visor_device(dev);
 252
 253         return sprintf(buf, "0x%lx\n",
 254                        visorchannel_get_nbytes(vdev->visorchannel));
 255 }
 256 static DEVICE_ATTR_RO(nbytes);
 257
 258 static ssize_t clientpartition_show(struct device *dev,
 259                                     struct device_attribute *attr, char *buf)
 260 {
 261         struct visor_device *vdev = to_visor_device(dev);
 262
 263         return sprintf(buf, "0x%llx\n",
 264                        visorchannel_get_clientpartition(vdev->visorchannel));
 265 }
 266 static DEVICE_ATTR_RO(clientpartition);
 267
 268 static ssize_t typeguid_show(struct device *dev, struct device_attribute *attr,
 269                              char *buf)
 270 {
 271         struct visor_device *vdev = to_visor_device(dev);
 272         char typeid[LINESIZE];
 273
 274         return sprintf(buf, "%s\n",
 275                        visorchannel_id(vdev->visorchannel, typeid));
 276 }
 277 static DEVICE_ATTR_RO(typeguid);
 278
 279 static ssize_t zoneguid_show(struct device *dev, struct device_attribute *attr,
 280                              char *buf)
 281 {
 282         struct visor_device *vdev = to_visor_device(dev);
 283         char zoneid[LINESIZE];
 284
 285         return sprintf(buf, "%s\n",
 286                        visorchannel_zoneid(vdev->visorchannel, zoneid));
 287 }
 288 static DEVICE_ATTR_RO(zoneguid);
 289
 290 static ssize_t typename_show(struct device *dev, struct device_attribute *attr,
 291                              char *buf)
 292 {
 293         int i = 0;
 294         struct bus_type *xbus = dev->bus;
 295         struct device_driver *xdrv = dev->driver;
 296         struct visor_driver *drv = NULL;
 297
 298         if (!xdrv)
 299                 return 0;
 300         i = xbus->match(dev, xdrv);
 301         if (!i)
 302                 return 0;
 303         drv = to_visor_driver(xdrv);
 304         return sprintf(buf, "%s\n", drv->channel_types[i - 1].name);
 305 }
 306 static DEVICE_ATTR_RO(typename);
 307
 308 static struct attribute *channel_attrs[] = {
 309         &dev_attr_physaddr.attr,
 310         &dev_attr_nbytes.attr,
 311         &dev_attr_clientpartition.attr,
 312         &dev_attr_typeguid.attr,
 313         &dev_attr_zoneguid.attr,
 314         &dev_attr_typename.attr,
 315         NULL
 316 };
 317
 318 ATTRIBUTE_GROUPS(channel);
 319
 320 /*
 321  *  BUS instance attributes
 322  *
 323  *  define & implement display of bus attributes under
 324  *  /sys/bus/visorbus/devices/visorbus<n>.
 325  */
 326 static ssize_t partition_handle_show(struct device *dev,
 327                                      struct device_attribute *attr, char *buf)
 328 {
 329         struct visor_device *vdev = to_visor_device(dev);
 330         u64 handle = visorchannel_get_clientpartition(vdev->visorchannel);
 331
 332         return sprintf(buf, "0x%llx\n", handle);
 333 }
 334 static DEVICE_ATTR_RO(partition_handle);
 335
 336 static ssize_t partition_guid_show(struct device *dev,
 337                                    struct device_attribute *attr, char *buf)
 338 {
 339         struct visor_device *vdev = to_visor_device(dev);
 340
 341         return sprintf(buf, "{%pUb}\n", &vdev->partition_guid);
 342 }
 343 static DEVICE_ATTR_RO(partition_guid);
 344
 345 static ssize_t partition_name_show(struct device *dev,
 346                                    struct device_attribute *attr, char *buf)
 347 {
 348         struct visor_device *vdev = to_visor_device(dev);
 349
 350         return sprintf(buf, "%s\n", vdev->name);
 351 }
 352 static DEVICE_ATTR_RO(partition_name);
 353
 354 static ssize_t channel_addr_show(struct device *dev,
 355                                  struct device_attribute *attr, char *buf)
 356 {
 357         struct visor_device *vdev = to_visor_device(dev);
 358         u64 addr = visorchannel_get_physaddr(vdev->visorchannel);
 359
 360         return sprintf(buf, "0x%llx\n", addr);
 361 }
 362 static DEVICE_ATTR_RO(channel_addr);
 363
 364 static ssize_t channel_bytes_show(struct device *dev,
 365                                   struct device_attribute *attr, char *buf)
 366 {
 367         struct visor_device *vdev = to_visor_device(dev);
 368         u64 nbytes = visorchannel_get_nbytes(vdev->visorchannel);
 369
 370         return sprintf(buf, "0x%llx\n", nbytes);
 371 }
 372 static DEVICE_ATTR_RO(channel_bytes);
 373
 374 static ssize_t channel_id_show(struct device *dev,
 375                                struct device_attribute *attr, char *buf)
 376 {
 377         struct visor_device *vdev = to_visor_device(dev);
 378         int len = 0;
 379
 380         visorchannel_id(vdev->visorchannel, buf);
 381         len = strlen(buf);
 382         buf[len++] = '\n';
 383         return len;
 384 }
 385 static DEVICE_ATTR_RO(channel_id);
 386
 387 static struct attribute *visorbus_attrs[] = {
 388         &dev_attr_partition_handle.attr,
 389         &dev_attr_partition_guid.attr,
 390         &dev_attr_partition_name.attr,
 391         &dev_attr_channel_addr.attr,
 392         &dev_attr_channel_bytes.attr,
 393         &dev_attr_channel_id.attr,
 394         NULL
 395 };
 396
 397 ATTRIBUTE_GROUPS(visorbus);
 398
 399 /*
 400  *  BUS debugfs entries
 401  *
 402  *  define & implement display of debugfs attributes under
 403  *  /sys/kernel/debug/visorbus/visorbus<n>.
 404  */
 405
 406 /*
 407  * vbuschannel_print_devinfo() - format a struct visor_vbus_deviceinfo
 408  *                               and write it to a seq_file
 409  * @devinfo: the struct visor_vbus_deviceinfo to format
 410  * @seq: seq_file to write to
 411  * @devix: the device index to be included in the output data, or -1 if no
 412  *         device index is to be included
 413  *
 414  * Reads @devInfo, and writes it in human-readable notation to @seq.
 415  */
 416 static void vbuschannel_print_devinfo(struct visor_vbus_deviceinfo *devinfo,
 417                                       struct seq_file *seq, int devix)
 418 {
 419         /* uninitialized vbus device entry */
 420         if (!isprint(devinfo->devtype[0]))
 421                 return;
 422         if (devix >= 0)
 423                 seq_printf(seq, "[%d]", devix);
 424         else
 425                 /* vbus device entry is for bus or chipset */
 426                 seq_puts(seq, "   ");
 427         /*
 428          * Note: because the s-Par back-end is free to scribble in this area,
 429          * we never assume '\0'-termination.
 430          */
 431         seq_printf(seq, "%-*.*s ", (int)sizeof(devinfo->devtype),
 432                    (int)sizeof(devinfo->devtype), devinfo->devtype);
 433         seq_printf(seq, "%-*.*s ", (int)sizeof(devinfo->drvname),
 434                    (int)sizeof(devinfo->drvname), devinfo->drvname);
 435         seq_printf(seq, "%.*s\n", (int)sizeof(devinfo->infostrs),
 436                    devinfo->infostrs);
 437 }
 438
 439 static int bus_info_debugfs_show(struct seq_file *seq, void *v)
 440 {
 441         int i = 0;
 442         unsigned long off;
 443         struct visor_vbus_deviceinfo dev_info;
 444         struct visor_device *vdev = seq->private;
 445         struct visorchannel *channel = vdev->visorchannel;
 446
 447         if (!channel)
 448                 return 0;
 449
 450         seq_printf(seq,
 451                    "Client device/driver info for %s partition (vbus #%u):\n",
 452                    ((vdev->name) ? (char *)(vdev->name) : ""),
 453                    vdev->chipset_bus_no);
 454         if (visorchannel_read(channel,
 455                               offsetof(struct visor_vbus_channel, chp_info),
 456                               &dev_info, sizeof(dev_info)) >= 0)
 457                 vbuschannel_print_devinfo(&dev_info, seq, -1);
 458         if (visorchannel_read(channel,
 459                               offsetof(struct visor_vbus_channel, bus_info),
 460                               &dev_info, sizeof(dev_info)) >= 0)
 461                 vbuschannel_print_devinfo(&dev_info, seq, -1);
 462
 463         off = offsetof(struct visor_vbus_channel, dev_info);
 464         while (off + sizeof(dev_info) <= visorchannel_get_nbytes(channel)) {
 465                 if (visorchannel_read(channel, off, &dev_info,
 466                                       sizeof(dev_info)) >= 0)
 467                         vbuschannel_print_devinfo(&dev_info, seq, i);
 468                 off += sizeof(dev_info);
 469                 i++;
 470         }
 471         return 0;
 472 }
 473
 474 static int bus_info_debugfs_open(struct inode *inode, struct file *file)
 475 {
 476         return single_open(file, bus_info_debugfs_show, inode->i_private);
 477 }
 478
 479 static const struct file_operations bus_info_debugfs_fops = {
 480         .owner = THIS_MODULE,
 481         .open = bus_info_debugfs_open,
 482         .read = seq_read,
 483         .llseek = seq_lseek,
 484         .release = single_release,
 485 };
 486
 487 static void dev_periodic_work(struct timer_list *t)
 488 {
 489         struct visor_device *dev = from_timer(dev, t, timer);
 490         struct visor_driver *drv = to_visor_driver(dev->device.driver);
 491
 492         drv->channel_interrupt(dev);
 493         mod_timer(&dev->timer, jiffies + POLLJIFFIES_NORMALCHANNEL);
 494 }
 495
 496 static int dev_start_periodic_work(struct visor_device *dev)
 497 {
 498         if (dev->being_removed || dev->timer_active)
 499                 return -EINVAL;
 500
 501         /* now up by at least 2 */
 502         get_device(&dev->device);
 503         dev->timer.expires = jiffies + POLLJIFFIES_NORMALCHANNEL;
 504         add_timer(&dev->timer);
 505         dev->timer_active = true;
 506         return 0;
 507 }
 508
 509 static void dev_stop_periodic_work(struct visor_device *dev)
 510 {
 511         if (!dev->timer_active)
 512                 return;
 513
 514         del_timer_sync(&dev->timer);
 515         dev->timer_active = false;
 516         put_device(&dev->device);
 517 }
 518
 519 /*
 520  * visordriver_remove_device() - handle visor device going away
 521  * @xdev: struct device for the visor device being removed
 522  *
 523  * This is called when device_unregister() is called for each child device
 524  * instance, to notify the appropriate visorbus function driver that the device
 525  * is going away, and to decrease the reference count of the device.
 526  *
 527  * Return: 0 iff successful
 528  */
 529 static int visordriver_remove_device(struct device *xdev)
 530 {
 531         struct visor_device *dev = to_visor_device(xdev);
 532         struct visor_driver *drv = to_visor_driver(xdev->driver);
 533
 534         mutex_lock(&dev->visordriver_callback_lock);
 535         dev->being_removed = true;
 536         drv->remove(dev);
 537         mutex_unlock(&dev->visordriver_callback_lock);
 538         dev_stop_periodic_work(dev);
 539         put_device(&dev->device);
 540         return 0;
 541 }
 542
 543 /*
 544  * visorbus_unregister_visor_driver() - unregisters the provided driver
 545  * @drv: the driver to unregister
 546  *
 547  * A visor function driver calls this function to unregister the driver,
 548  * i.e., within its module_exit function.
 549  */
 550 void visorbus_unregister_visor_driver(struct visor_driver *drv)
 551 {
 552         driver_unregister(&drv->driver);
 553 }
 554 EXPORT_SYMBOL_GPL(visorbus_unregister_visor_driver);
 555
 556 /*
 557  * visorbus_read_channel() - reads from the designated channel into
 558  *                           the provided buffer
 559  * @dev:    the device whose channel is read from
 560  * @offset: the offset into the channel at which reading starts
 561  * @dest:   the destination buffer that is written into from the channel
 562  * @nbytes: the number of bytes to read from the channel
 563  *
 564  * If receiving a message, use the visorchannel_signalremove() function instead.
 565  *
 566  * Return: integer indicating success (zero) or failure (non-zero)
 567  */
 568 int visorbus_read_channel(struct visor_device *dev, unsigned long offset,
 569                           void *dest, unsigned long nbytes)
 570 {
 571         return visorchannel_read(dev->visorchannel, offset, dest, nbytes);
 572 }
 573 EXPORT_SYMBOL_GPL(visorbus_read_channel);
 574
 575 /*
 576  * visorbus_write_channel() - writes the provided buffer into the designated
 577  *                            channel
 578  * @dev:    the device whose channel is written to
 579  * @offset: the offset into the channel at which writing starts
 580  * @src:    the source buffer that is written into the channel
 581  * @nbytes: the number of bytes to write into the channel
 582  *
 583  * If sending a message, use the visorchannel_signalinsert() function instead.
 584  *
 585  * Return: integer indicating success (zero) or failure (non-zero)
 586  */
 587 int visorbus_write_channel(struct visor_device *dev, unsigned long offset,
 588                            void *src, unsigned long nbytes)
 589 {
 590         return visorchannel_write(dev->visorchannel, offset, src, nbytes);
 591 }
 592 EXPORT_SYMBOL_GPL(visorbus_write_channel);
 593
 594 /*
 595  * visorbus_enable_channel_interrupts() - enables interrupts on the
 596  *                                        designated device
 597  * @dev: the device on which to enable interrupts
 598  *
 599  * Currently we don't yet have a real interrupt, so for now we just call the
 600  * interrupt function periodically via a timer.
 601  */
 602 int visorbus_enable_channel_interrupts(struct visor_device *dev)
 603 {
 604         struct visor_driver *drv = to_visor_driver(dev->device.driver);
 605
 606         if (!drv->channel_interrupt) {
 607                 dev_err(&dev->device, "%s no interrupt function!\n", __func__);
 608                 return -ENOENT;
 609         }
 610
 611         return dev_start_periodic_work(dev);
 612 }
 613 EXPORT_SYMBOL_GPL(visorbus_enable_channel_interrupts);
 614
 615 /*
 616  * visorbus_disable_channel_interrupts() - disables interrupts on the
 617  *                                         designated device
 618  * @dev: the device on which to disable interrupts
 619  */
 620 void visorbus_disable_channel_interrupts(struct visor_device *dev)
 621 {
 622         dev_stop_periodic_work(dev);
 623 }
 624 EXPORT_SYMBOL_GPL(visorbus_disable_channel_interrupts);
 625
 626 /*
 627  * create_visor_device() - create visor device as a result of receiving the
 628  *                         controlvm device_create message for a new device
 629  * @dev: a freshly-zeroed struct visor_device, containing only filled-in values
 630  *       for chipset_bus_no and chipset_dev_no, that will be initialized
 631  *
 632  * This is how everything starts from the device end.
 633  * This function is called when a channel first appears via a ControlVM
 634  * message.  In response, this function allocates a visor_device to correspond
 635  * to the new channel, and attempts to connect it the appropriate * driver. If
 636  * the appropriate driver is found, the visor_driver.probe() function for that
 637  * driver will be called, and will be passed the new * visor_device that we
 638  * just created.
 639  *
 640  * It's ok if the appropriate driver is not yet loaded, because in that case
 641  * the new device struct will just stick around in the bus' list of devices.
 642  * When the appropriate driver calls visorbus_register_visor_driver(), the
 643  * visor_driver.probe() for the new driver will be called with the new device.
 644  *
 645  * Return: 0 if successful, otherwise the negative value returned by
 646  *         device_add() indicating the reason for failure
 647  */
 648 int create_visor_device(struct visor_device *dev)
 649 {
 650         int err;
 651         u32 chipset_bus_no = dev->chipset_bus_no;
 652         u32 chipset_dev_no = dev->chipset_dev_no;
 653
 654         mutex_init(&dev->visordriver_callback_lock);
 655         dev->device.bus = &visorbus_type;
 656         dev->device.groups = channel_groups;
 657         device_initialize(&dev->device);
 658         dev->device.release = visorbus_release_device;
 659         /* keep a reference just for us (now 2) */
 660         get_device(&dev->device);
 661         timer_setup(&dev->timer, dev_periodic_work, 0);
 662         /*
 663          * bus_id must be a unique name with respect to this bus TYPE (NOT bus
 664          * instance).  That's why we need to include the bus number within the
 665          * name.
 666          */
 667         err = dev_set_name(&dev->device, "vbus%u:dev%u",
 668                            chipset_bus_no, chipset_dev_no);
 669         if (err)
 670                 goto err_put;
 671         /*
 672          * device_add does this:
 673          *    bus_add_device(dev)
 674          *    ->device_attach(dev)
 675          *      ->for each driver drv registered on the bus that dev is on
 676          *          if (dev.drv)  **  device already has a driver **
 677          *            ** not sure we could ever get here... **
 678          *          else
 679          *            if (bus.match(dev,drv)) [visorbus_match]
 680          *              dev.drv = drv
 681          *              if (!drv.probe(dev))  [visordriver_probe_device]
 682          *                dev.drv = NULL
 683          *
 684          * Note that device_add does NOT fail if no driver failed to claim the
 685          * device.  The device will be linked onto bus_type.klist_devices
 686          * regardless (use bus_for_each_dev).
 687          */
 688         err = device_add(&dev->device);
 689         if (err < 0)
 690                 goto err_put;
 691         list_add_tail(&dev->list_all, &list_all_device_instances);
 692         dev->state.created = 1;
 693         visorbus_response(dev, err, CONTROLVM_DEVICE_CREATE);
 694         /* success: reference kept via unmatched get_device() */
 695         return 0;
 696
 697 err_put:
 698         put_device(&dev->device);
 699         dev_err(&dev->device, "Creating visor device failed. %d\n", err);
 700         return err;
 701 }
 702
 703 void remove_visor_device(struct visor_device *dev)
 704 {
 705         list_del(&dev->list_all);
 706         put_device(&dev->device);
 707         if (dev->pending_msg_hdr)
 708                 visorbus_response(dev, 0, CONTROLVM_DEVICE_DESTROY);
 709         device_unregister(&dev->device);
 710 }
 711
 712 static int get_vbus_header_info(struct visorchannel *chan,
 713                                 struct device *dev,
 714                                 struct visor_vbus_headerinfo *hdr_info)
 715 {
 716         int err;
 717
 718         if (!visor_check_channel(visorchannel_get_header(chan),
 719                                  dev,
 720                                  &visor_vbus_channel_guid,
 721                                  "vbus",
 722                                  sizeof(struct visor_vbus_channel),
 723                                  VISOR_VBUS_CHANNEL_VERSIONID,
 724                                  VISOR_CHANNEL_SIGNATURE))
 725                 return -EINVAL;
 726
 727         err = visorchannel_read(chan, sizeof(struct channel_header), hdr_info,
 728                                 sizeof(*hdr_info));
 729         if (err < 0)
 730                 return err;
 731         if (hdr_info->struct_bytes < sizeof(struct visor_vbus_headerinfo))
 732                 return -EINVAL;
 733         if (hdr_info->device_info_struct_bytes <
 734             sizeof(struct visor_vbus_deviceinfo))
 735                 return -EINVAL;
 736         return 0;
 737 }
 738
 739 /*
 740  * write_vbus_chp_info() - write the contents of <info> to the struct
 741  *                         visor_vbus_channel.chp_info
 742  * @chan:     indentifies the s-Par channel that will be updated
 743  * @hdr_info: used to find appropriate channel offset to write data
 744  * @info:     contains the information to write
 745  *
 746  * Writes chipset info into the channel memory to be used for diagnostic
 747  * purposes.
 748  *
 749  * Returns no value since this is debug information and not needed for
 750  * device functionality.
 751  */
 752 static void write_vbus_chp_info(struct visorchannel *chan,
 753                                 struct visor_vbus_headerinfo *hdr_info,
 754                                 struct visor_vbus_deviceinfo *info)
 755 {
 756         int off;
 757
 758         if (hdr_info->chp_info_offset == 0)
 759                 return;
 760
 761         off = sizeof(struct channel_header) + hdr_info->chp_info_offset;
 762         visorchannel_write(chan, off, info, sizeof(*info));
 763 }
 764
 765 /*
 766  * write_vbus_bus_info() - write the contents of <info> to the struct
 767  *                         visor_vbus_channel.bus_info
 768  * @chan:     indentifies the s-Par channel that will be updated
 769  * @hdr_info: used to find appropriate channel offset to write data
 770  * @info:     contains the information to write
 771  *
 772  * Writes bus info into the channel memory to be used for diagnostic
 773  * purposes.
 774  *
 775  * Returns no value since this is debug information and not needed for
 776  * device functionality.
 777  */
 778 static void write_vbus_bus_info(struct visorchannel *chan,
 779                                 struct visor_vbus_headerinfo *hdr_info,
 780                                 struct visor_vbus_deviceinfo *info)
 781 {
 782         int off;
 783
 784         if (hdr_info->bus_info_offset == 0)
 785                 return;
 786
 787         off = sizeof(struct channel_header) + hdr_info->bus_info_offset;
 788         visorchannel_write(chan, off, info, sizeof(*info));
 789 }
 790
 791 /*
 792  * write_vbus_dev_info() - write the contents of <info> to the struct
 793  *                         visor_vbus_channel.dev_info[<devix>]
 794  * @chan:     indentifies the s-Par channel that will be updated
 795  * @hdr_info: used to find appropriate channel offset to write data
 796  * @info:     contains the information to write
 797  * @devix:    the relative device number (0..n-1) of the device on the bus
 798  *
 799  * Writes device info into the channel memory to be used for diagnostic
 800  * purposes.
 801  *
 802  * Returns no value since this is debug information and not needed for
 803  * device functionality.
 804  */
 805 static void write_vbus_dev_info(struct visorchannel *chan,
 806                                 struct visor_vbus_headerinfo *hdr_info,
 807                                 struct visor_vbus_deviceinfo *info,
 808                                 unsigned int devix)
 809 {
 810         int off;
 811
 812         if (hdr_info->dev_info_offset == 0)
 813                 return;
 814         off = (sizeof(struct channel_header) + hdr_info->dev_info_offset) +
 815               (hdr_info->device_info_struct_bytes * devix);
 816         visorchannel_write(chan, off, info, sizeof(*info));
 817 }
 818
 819 static void bus_device_info_init(
 820                 struct visor_vbus_deviceinfo *bus_device_info_ptr,
 821                 const char *dev_type, const char *drv_name)
 822 {
 823         memset(bus_device_info_ptr, 0, sizeof(struct visor_vbus_deviceinfo));
 824         snprintf(bus_device_info_ptr->devtype,
 825                  sizeof(bus_device_info_ptr->devtype),
 826                  "%s", (dev_type) ? dev_type : "unknownType");
 827         snprintf(bus_device_info_ptr->drvname,
 828                  sizeof(bus_device_info_ptr->drvname),
 829                  "%s", (drv_name) ? drv_name : "unknownDriver");
 830         snprintf(bus_device_info_ptr->infostrs,
 831                  sizeof(bus_device_info_ptr->infostrs), "kernel ver. %s",
 832                  utsname()->release);
 833 }
 834
 835 /*
 836  * publish_vbus_dev_info() - for a child device just created on a client bus,
 837  *                           fill in information about the driver that is
 838  *                           controlling this device into the appropriate slot
 839  *                           within the vbus channel of the bus instance
 840  * @visordev: struct visor_device for the desired device
 841  */
 842 static void publish_vbus_dev_info(struct visor_device *visordev)
 843 {
 844         int i;
 845         struct visor_device *bdev;
 846         struct visor_driver *visordrv;
 847         u32 bus_no = visordev->chipset_bus_no;
 848         u32 dev_no = visordev->chipset_dev_no;
 849         struct visor_vbus_deviceinfo dev_info;
 850         const char *chan_type_name = NULL;
 851         struct visor_vbus_headerinfo *hdr_info;
 852
 853         if (!visordev->device.driver)
 854                 return;
 855         bdev = visorbus_get_device_by_id(bus_no, BUS_ROOT_DEVICE, NULL);
 856         if (!bdev)
 857                 return;
 858         hdr_info = (struct visor_vbus_headerinfo *)bdev->vbus_hdr_info;
 859         if (!hdr_info)
 860                 return;
 861         visordrv = to_visor_driver(visordev->device.driver);
 862
 863         /*
 864          * Within the list of device types (by GUID) that the driver
 865          * says it supports, find out which one of those types matches
 866          * the type of this device, so that we can include the device
 867          * type name
 868          */
 869         for (i = 0; visordrv->channel_types[i].name; i++) {
 870                 if (guid_equal(&visordrv->channel_types[i].guid,
 871                                &visordev->channel_type_guid)) {
 872                         chan_type_name = visordrv->channel_types[i].name;
 873                         break;
 874                 }
 875         }
 876         bus_device_info_init(&dev_info, chan_type_name, visordrv->name);
 877         write_vbus_dev_info(bdev->visorchannel, hdr_info, &dev_info, dev_no);
 878         write_vbus_chp_info(bdev->visorchannel, hdr_info, &chipset_driverinfo);
 879         write_vbus_bus_info(bdev->visorchannel, hdr_info,
 880                             &clientbus_driverinfo);
 881 }
 882
 883 /*
 884  * visordriver_probe_device() - handle new visor device coming online
 885  * @xdev: struct device for the visor device being probed
 886  *
 887  * This is called automatically upon adding a visor_device (device_add), or
 888  * adding a visor_driver (visorbus_register_visor_driver), but only after
 889  * visorbus_match() has returned 1 to indicate a successful match between
 890  * driver and device.
 891  *
 892  * If successful, a reference to the device will be held onto via get_device().
 893  *
 894  * Return: 0 if successful, meaning the function driver's probe() function
 895  *         was successful with this device, otherwise a negative errno
 896  *         value indicating failure reason
 897  */
 898 static int visordriver_probe_device(struct device *xdev)
 899 {
 900         int err;
 901         struct visor_driver *drv = to_visor_driver(xdev->driver);
 902         struct visor_device *dev = to_visor_device(xdev);
 903
 904         mutex_lock(&dev->visordriver_callback_lock);
 905         dev->being_removed = false;
 906         err = drv->probe(dev);
 907         if (err) {
 908                 mutex_unlock(&dev->visordriver_callback_lock);
 909                 return err;
 910         }
 911         /* success: reference kept via unmatched get_device() */
 912         get_device(&dev->device);
 913         publish_vbus_dev_info(dev);
 914         mutex_unlock(&dev->visordriver_callback_lock);
 915         return 0;
 916 }
 917
 918 /*
 919  * visorbus_register_visor_driver() - registers the provided visor driver for
 920  *                                    handling one or more visor device
 921  *                                    types (channel_types)
 922  * @drv: the driver to register
 923  *
 924  * A visor function driver calls this function to register the driver. The
 925  * caller MUST fill in the following fields within the #drv structure:
 926  *     name, version, owner, channel_types, probe, remove
 927  *
 928  * Here's how the whole Linux bus / driver / device model works.
 929  *
 930  * At system start-up, the visorbus kernel module is loaded, which registers
 931  * visorbus_type as a bus type, using bus_register().
 932  *
 933  * All kernel modules that support particular device types on a
 934  * visorbus bus are loaded.  Each of these kernel modules calls
 935  * visorbus_register_visor_driver() in their init functions, passing a
 936  * visor_driver struct.  visorbus_register_visor_driver() in turn calls
 937  * register_driver(&visor_driver.driver).  This .driver member is
 938  * initialized with generic methods (like probe), whose sole responsibility
 939  * is to act as a broker for the real methods, which are within the
 940  * visor_driver struct.  (This is the way the subclass behavior is
 941  * implemented, since visor_driver is essentially a subclass of the
 942  * generic driver.)  Whenever a driver_register() happens, core bus code in
 943  * the kernel does (see device_attach() in drivers/base/dd.c):
 944  *
 945  *     for each dev associated with the bus (the bus that driver is on) that
 946  *     does not yet have a driver
 947  *         if bus.match(dev,newdriver) == yes_matched  ** .match specified
 948  *                                                ** during bus_register().
 949  *             newdriver.probe(dev)  ** for visor drivers, this will call
 950  *                   ** the generic driver.probe implemented in visorbus.c,
 951  *                   ** which in turn calls the probe specified within the
 952  *                   ** struct visor_driver (which was specified by the
 953  *                   ** actual device driver as part of
 954  *                   ** visorbus_register_visor_driver()).
 955  *
 956  * The above dance also happens when a new device appears.
 957  * So the question is, how are devices created within the system?
 958  * Basically, just call device_add(dev).  See pci_bus_add_devices().
 959  * pci_scan_device() shows an example of how to build a device struct.  It
 960  * returns the newly-created struct to pci_scan_single_device(), who adds it
 961  * to the list of devices at PCIBUS.devices.  That list of devices is what
 962  * is traversed by pci_bus_add_devices().
 963  *
 964  * Return: integer indicating success (zero) or failure (non-zero)
 965  */
 966 int visorbus_register_visor_driver(struct visor_driver *drv)
 967 {
 968         /* can't register on a nonexistent bus */
 969         if (!initialized)
 970                 return -ENODEV;
 971         if (!drv->probe)
 972                 return -EINVAL;
 973         if (!drv->remove)
 974                 return -EINVAL;
 975         if (!drv->pause)
 976                 return -EINVAL;
 977         if (!drv->resume)
 978                 return -EINVAL;
 979
 980         drv->driver.name = drv->name;
 981         drv->driver.bus = &visorbus_type;
 982         drv->driver.probe = visordriver_probe_device;
 983         drv->driver.remove = visordriver_remove_device;
 984         drv->driver.owner = drv->owner;
 985         /*
 986          * driver_register does this:
 987          *   bus_add_driver(drv)
 988          *   ->if (drv.bus)  ** (bus_type) **
 989          *       driver_attach(drv)
 990          *         for each dev with bus type of drv.bus
 991          *           if (!dev.drv)  ** no driver assigned yet **
 992          *             if (bus.match(dev,drv))  [visorbus_match]
 993          *               dev.drv = drv
 994          *               if (!drv.probe(dev))   [visordriver_probe_device]
 995          *                 dev.drv = NULL
 996          */
 997         return driver_register(&drv->driver);
 998 }
 999 EXPORT_SYMBOL_GPL(visorbus_register_visor_driver);
1000
1001 /*
1002  * visorbus_create_instance() - create a device instance for the visorbus itself
1003  * @dev: struct visor_device indicating the bus instance
1004  *
1005  * Return: 0 for success, otherwise negative errno value indicating reason for
1006  *         failure
1007  */
1008 int visorbus_create_instance(struct visor_device *dev)
1009 {
1010         int id = dev->chipset_bus_no;
1011         int err;
1012         struct visor_vbus_headerinfo *hdr_info;
1013
1014         hdr_info = kzalloc(sizeof(*hdr_info), GFP_KERNEL);
1015         if (!hdr_info)
1016                 return -ENOMEM;
1017         dev_set_name(&dev->device, "visorbus%d", id);
1018         dev->device.bus = &visorbus_type;
1019         dev->device.groups = visorbus_groups;
1020         dev->device.release = visorbus_release_busdevice;
1021         dev->debugfs_dir = debugfs_create_dir(dev_name(&dev->device),
1022                                               visorbus_debugfs_dir);
1023         dev->debugfs_bus_info = debugfs_create_file("client_bus_info", 0440,
1024                                                     dev->debugfs_dir, dev,
1025                                                     &bus_info_debugfs_fops);
1026         dev_set_drvdata(&dev->device, dev);
1027         err = get_vbus_header_info(dev->visorchannel, &dev->device, hdr_info);
1028         if (err < 0)
1029                 goto err_debugfs_dir;
1030         err = device_register(&dev->device);
1031         if (err < 0)
1032                 goto err_debugfs_dir;
1033         list_add_tail(&dev->list_all, &list_all_bus_instances);
1034         dev->state.created = 1;
1035         dev->vbus_hdr_info = (void *)hdr_info;
1036         write_vbus_chp_info(dev->visorchannel, hdr_info, &chipset_driverinfo);
1037         write_vbus_bus_info(dev->visorchannel, hdr_info, &clientbus_driverinfo);
1038         visorbus_response(dev, err, CONTROLVM_BUS_CREATE);
1039         return 0;
1040
1041 err_debugfs_dir:
1042         debugfs_remove_recursive(dev->debugfs_dir);
1043         kfree(hdr_info);
1044         dev_err(&dev->device, "%s failed: %d\n", __func__, err);
1045         return err;
1046 }
1047
1048 /*
1049  * visorbus_remove_instance() - remove a device instance for the visorbus itself
1050  * @dev: struct visor_device indentifying the bus to remove
1051  */
1052 void visorbus_remove_instance(struct visor_device *dev)
1053 {
1054         /*
1055          * Note that this will result in the release method for
1056          * dev->dev being called, which will call
1057          * visorbus_release_busdevice().  This has something to do with
1058          * the put_device() done in device_unregister(), but I have never
1059          * successfully been able to trace thru the code to see where/how
1060          * release() gets called.  But I know it does.
1061          */
1062         kfree(dev->vbus_hdr_info);
1063         list_del(&dev->list_all);
1064         if (dev->pending_msg_hdr)
1065                 visorbus_response(dev, 0, CONTROLVM_BUS_DESTROY);
1066         device_unregister(&dev->device);
1067 }
1068
1069 /*
1070  * remove_all_visor_devices() - remove all child visorbus device instances
1071  */
1072 static void remove_all_visor_devices(void)
1073 {
1074         struct list_head *listentry, *listtmp;
1075
1076         list_for_each_safe(listentry, listtmp, &list_all_device_instances) {
1077                 struct visor_device *dev;
1078
1079                 dev = list_entry(listentry, struct visor_device, list_all);
1080                 remove_visor_device(dev);
1081         }
1082 }
1083
1084 /*
1085  * pause_state_change_complete() - the callback function to be called by a
1086  *                                 visorbus function driver when a
1087  *                                 pending "pause device" operation has
1088  *                                 completed
1089  * @dev: struct visor_device identifying the paused device
1090  * @status: 0 iff the pause state change completed successfully, otherwise
1091  *          a negative errno value indicating the reason for failure
1092  */
1093 static void pause_state_change_complete(struct visor_device *dev, int status)
1094 {
1095         if (!dev->pausing)
1096                 return;
1097
1098         dev->pausing = false;
1099         visorbus_device_changestate_response(dev, status,
1100                                              segment_state_standby);
1101 }
1102
1103 /*
1104  * resume_state_change_complete() - the callback function to be called by a
1105  *                                  visorbus function driver when a
1106  *                                  pending "resume device" operation has
1107  *                                  completed
1108  * @dev: struct visor_device identifying the resumed device
1109  * @status: 0 iff the resume state change completed successfully, otherwise
1110  *          a negative errno value indicating the reason for failure
1111  */
1112 static void resume_state_change_complete(struct visor_device *dev, int status)
1113 {
1114         if (!dev->resuming)
1115                 return;
1116
1117         dev->resuming = false;
1118         /*
1119          * Notify the chipset driver that the resume is complete,
1120          * which will presumably want to send some sort of response to
1121          * the initiator.
1122          */
1123         visorbus_device_changestate_response(dev, status,
1124                                              segment_state_running);
1125 }
1126
1127 /*
1128  * visorchipset_initiate_device_pause_resume() - start a pause or resume
1129  *                                               operation for a visor device
1130  * @dev: struct visor_device identifying the device being paused or resumed
1131  * @is_pause: true to indicate pause operation, false to indicate resume
1132  *
1133  * Tell the subordinate function driver for a specific device to pause
1134  * or resume that device.  Success/failure result is returned asynchronously
1135  * via a callback function; see pause_state_change_complete() and
1136  * resume_state_change_complete().
1137  */
1138 static int visorchipset_initiate_device_pause_resume(struct visor_device *dev,
1139                                                      bool is_pause)
1140 {
1141         int err;
1142         struct visor_driver *drv;
1143
1144         /* If no driver associated with the device nothing to pause/resume */
1145         if (!dev->device.driver)
1146                 return 0;
1147         if (dev->pausing || dev->resuming)
1148                 return -EBUSY;
1149
1150         drv = to_visor_driver(dev->device.driver);
1151         if (is_pause) {
1152                 dev->pausing = true;
1153                 err = drv->pause(dev, pause_state_change_complete);
1154         } else {
1155                 /*
1156                  * The vbus_dev_info structure in the channel was been cleared,
1157                  * make sure it is valid.
1158                  */
1159                 publish_vbus_dev_info(dev);
1160                 dev->resuming = true;
1161                 err = drv->resume(dev, resume_state_change_complete);
1162         }
1163         return err;
1164 }
1165
1166 /*
1167  * visorchipset_device_pause() - start a pause operation for a visor device
1168  * @dev_info: struct visor_device identifying the device being paused
1169  *
1170  * Tell the subordinate function driver for a specific device to pause
1171  * that device.  Success/failure result is returned asynchronously
1172  * via a callback function; see pause_state_change_complete().
1173  */
1174 int visorchipset_device_pause(struct visor_device *dev_info)
1175 {
1176         int err;
1177
1178         err = visorchipset_initiate_device_pause_resume(dev_info, true);
1179         if (err < 0) {
1180                 dev_info->pausing = false;
1181                 return err;
1182         }
1183         return 0;
1184 }
1185
1186 /*
1187  * visorchipset_device_resume() - start a resume operation for a visor device
1188  * @dev_info: struct visor_device identifying the device being resumed
1189  *
1190  * Tell the subordinate function driver for a specific device to resume
1191  * that device.  Success/failure result is returned asynchronously
1192  * via a callback function; see resume_state_change_complete().
1193  */
1194 int visorchipset_device_resume(struct visor_device *dev_info)
1195 {
1196         int err;
1197
1198         err = visorchipset_initiate_device_pause_resume(dev_info, false);
1199         if (err < 0) {
1200                 dev_info->resuming = false;
1201                 return err;
1202         }
1203         return 0;
1204 }
1205
1206 int visorbus_init(void)
1207 {
1208         int err;
1209
1210         visorbus_debugfs_dir = debugfs_create_dir("visorbus", NULL);
1211         bus_device_info_init(&clientbus_driverinfo, "clientbus", "visorbus");
1212         err = bus_register(&visorbus_type);
1213         if (err < 0)
1214                 return err;
1215         initialized = true;
1216         bus_device_info_init(&chipset_driverinfo, "chipset", "visorchipset");
1217         return 0;
1218 }
1219
1220 void visorbus_exit(void)
1221 {
1222         struct list_head *listentry, *listtmp;
1223
1224         remove_all_visor_devices();
1225         list_for_each_safe(listentry, listtmp, &list_all_bus_instances) {
1226                 struct visor_device *dev;
1227
1228                 dev = list_entry(listentry, struct visor_device, list_all);
1229                 visorbus_remove_instance(dev);
1230         }
1231         bus_unregister(&visorbus_type);
1232         initialized = false;
1233         debugfs_remove_recursive(visorbus_debugfs_dir);
1234 }