kernel/irq/msi.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2014 Intel Corp.
   4  * Author: Jiang Liu <jiang.liu@linux.intel.com>
   5  *
   6  * This file is licensed under GPLv2.
   7  *
   8  * This file contains common code to support Message Signalled Interrupt for
   9  * PCI compatible and non PCI compatible devices.
  10  */
  11 #include <linux/types.h>
  12 #include <linux/device.h>
  13 #include <linux/irq.h>
  14 #include <linux/irqdomain.h>
  15 #include <linux/msi.h>
  16 #include <linux/slab.h>
  17
  18 #include "internals.h"
  19
  20 /**
  21  * alloc_msi_entry - Allocate an initialize msi_entry
  22  * @dev:        Pointer to the device for which this is allocated
  23  * @nvec:       The number of vectors used in this entry
  24  * @affinity:   Optional pointer to an affinity mask array size of @nvec
  25  *
  26  * If @affinity is not NULL then an affinity array[@nvec] is allocated
  27  * and the affinity masks and flags from @affinity are copied.
  28  */
  29 struct msi_desc *alloc_msi_entry(struct device *dev, int nvec,
  30                                  const struct irq_affinity_desc *affinity)
  31 {
  32         struct msi_desc *desc;
  33
  34         desc = kzalloc(sizeof(*desc), GFP_KERNEL);
  35         if (!desc)
  36                 return NULL;
  37
  38         INIT_LIST_HEAD(&desc->list);
  39         desc->dev = dev;
  40         desc->nvec_used = nvec;
  41         if (affinity) {
  42                 desc->affinity = kmemdup(affinity,
  43                         nvec * sizeof(*desc->affinity), GFP_KERNEL);
  44                 if (!desc->affinity) {
  45                         kfree(desc);
  46                         return NULL;
  47                 }
  48         }
  49
  50         return desc;
  51 }
  52
  53 void free_msi_entry(struct msi_desc *entry)
  54 {
  55         kfree(entry->affinity);
  56         kfree(entry);
  57 }
  58
  59 void __get_cached_msi_msg(struct msi_desc *entry, struct msi_msg *msg)
  60 {
  61         *msg = entry->msg;
  62 }
  63
  64 void get_cached_msi_msg(unsigned int irq, struct msi_msg *msg)
  65 {
  66         struct msi_desc *entry = irq_get_msi_desc(irq);
  67
  68         __get_cached_msi_msg(entry, msg);
  69 }
  70 EXPORT_SYMBOL_GPL(get_cached_msi_msg);
  71
  72 #ifdef CONFIG_GENERIC_MSI_IRQ_DOMAIN
  73 static inline void irq_chip_write_msi_msg(struct irq_data *data,
  74                                           struct msi_msg *msg)
  75 {
  76         data->chip->irq_write_msi_msg(data, msg);
  77 }
  78
  79 static void msi_check_level(struct irq_domain *domain, struct msi_msg *msg)
  80 {
  81         struct msi_domain_info *info = domain->host_data;
  82
  83         /*
  84          * If the MSI provider has messed with the second message and
  85          * not advertized that it is level-capable, signal the breakage.
  86          */
  87         WARN_ON(!((info->flags & MSI_FLAG_LEVEL_CAPABLE) &&
  88                   (info->chip->flags & IRQCHIP_SUPPORTS_LEVEL_MSI)) &&
  89                 (msg[1].address_lo || msg[1].address_hi || msg[1].data));
  90 }
  91
  92 /**
  93  * msi_domain_set_affinity - Generic affinity setter function for MSI domains
  94  * @irq_data:   The irq data associated to the interrupt
  95  * @mask:       The affinity mask to set
  96  * @force:      Flag to enforce setting (disable online checks)
  97  *
  98  * Intended to be used by MSI interrupt controllers which are
  99  * implemented with hierarchical domains.
 100  */
 101 int msi_domain_set_affinity(struct irq_data *irq_data,
 102                             const struct cpumask *mask, bool force)
 103 {
 104         struct irq_data *parent = irq_data->parent_data;
 105         struct msi_msg msg[2] = { [1] = { }, };
 106         int ret;
 107
 108         ret = parent->chip->irq_set_affinity(parent, mask, force);
 109         if (ret >= 0 && ret != IRQ_SET_MASK_OK_DONE) {
 110                 BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
 111                 msi_check_level(irq_data->domain, msg);
 112                 irq_chip_write_msi_msg(irq_data, msg);
 113         }
 114
 115         return ret;
 116 }
 117
 118 static int msi_domain_activate(struct irq_domain *domain,
 119                                struct irq_data *irq_data, bool early)
 120 {
 121         struct msi_msg msg[2] = { [1] = { }, };
 122
 123         BUG_ON(irq_chip_compose_msi_msg(irq_data, msg));
 124         msi_check_level(irq_data->domain, msg);
 125         irq_chip_write_msi_msg(irq_data, msg);
 126         return 0;
 127 }
 128
 129 static void msi_domain_deactivate(struct irq_domain *domain,
 130                                   struct irq_data *irq_data)
 131 {
 132         struct msi_msg msg[2];
 133
 134         memset(msg, 0, sizeof(msg));
 135         irq_chip_write_msi_msg(irq_data, msg);
 136 }
 137
 138 static int msi_domain_alloc(struct irq_domain *domain, unsigned int virq,
 139                             unsigned int nr_irqs, void *arg)
 140 {
 141         struct msi_domain_info *info = domain->host_data;
 142         struct msi_domain_ops *ops = info->ops;
 143         irq_hw_number_t hwirq = ops->get_hwirq(info, arg);
 144         int i, ret;
 145
 146         if (irq_find_mapping(domain, hwirq) > 0)
 147                 return -EEXIST;
 148
 149         if (domain->parent) {
 150                 ret = irq_domain_alloc_irqs_parent(domain, virq, nr_irqs, arg);
 151                 if (ret < 0)
 152                         return ret;
 153         }
 154
 155         for (i = 0; i < nr_irqs; i++) {
 156                 ret = ops->msi_init(domain, info, virq + i, hwirq + i, arg);
 157                 if (ret < 0) {
 158                         if (ops->msi_free) {
 159                                 for (i--; i > 0; i--)
 160                                         ops->msi_free(domain, info, virq + i);
 161                         }
 162                         irq_domain_free_irqs_top(domain, virq, nr_irqs);
 163                         return ret;
 164                 }
 165         }
 166
 167         return 0;
 168 }
 169
 170 static void msi_domain_free(struct irq_domain *domain, unsigned int virq,
 171                             unsigned int nr_irqs)
 172 {
 173         struct msi_domain_info *info = domain->host_data;
 174         int i;
 175
 176         if (info->ops->msi_free) {
 177                 for (i = 0; i < nr_irqs; i++)
 178                         info->ops->msi_free(domain, info, virq + i);
 179         }
 180         irq_domain_free_irqs_top(domain, virq, nr_irqs);
 181 }
 182
 183 static const struct irq_domain_ops msi_domain_ops = {
 184         .alloc          = msi_domain_alloc,
 185         .free           = msi_domain_free,
 186         .activate       = msi_domain_activate,
 187         .deactivate     = msi_domain_deactivate,
 188 };
 189
 190 #ifdef GENERIC_MSI_DOMAIN_OPS
 191 static irq_hw_number_t msi_domain_ops_get_hwirq(struct msi_domain_info *info,
 192                                                 msi_alloc_info_t *arg)
 193 {
 194         return arg->hwirq;
 195 }
 196
 197 static int msi_domain_ops_prepare(struct irq_domain *domain, struct device *dev,
 198                                   int nvec, msi_alloc_info_t *arg)
 199 {
 200         memset(arg, 0, sizeof(*arg));
 201         return 0;
 202 }
 203
 204 static void msi_domain_ops_set_desc(msi_alloc_info_t *arg,
 205                                     struct msi_desc *desc)
 206 {
 207         arg->desc = desc;
 208 }
 209 #else
 210 #define msi_domain_ops_get_hwirq        NULL
 211 #define msi_domain_ops_prepare          NULL
 212 #define msi_domain_ops_set_desc         NULL
 213 #endif /* !GENERIC_MSI_DOMAIN_OPS */
 214
 215 static int msi_domain_ops_init(struct irq_domain *domain,
 216                                struct msi_domain_info *info,
 217                                unsigned int virq, irq_hw_number_t hwirq,
 218                                msi_alloc_info_t *arg)
 219 {
 220         irq_domain_set_hwirq_and_chip(domain, virq, hwirq, info->chip,
 221                                       info->chip_data);
 222         if (info->handler && info->handler_name) {
 223                 __irq_set_handler(virq, info->handler, 0, info->handler_name);
 224                 if (info->handler_data)
 225                         irq_set_handler_data(virq, info->handler_data);
 226         }
 227         return 0;
 228 }
 229
 230 static int msi_domain_ops_check(struct irq_domain *domain,
 231                                 struct msi_domain_info *info,
 232                                 struct device *dev)
 233 {
 234         return 0;
 235 }
 236
 237 static struct msi_domain_ops msi_domain_ops_default = {
 238         .get_hwirq      = msi_domain_ops_get_hwirq,
 239         .msi_init       = msi_domain_ops_init,
 240         .msi_check      = msi_domain_ops_check,
 241         .msi_prepare    = msi_domain_ops_prepare,
 242         .set_desc       = msi_domain_ops_set_desc,
 243 };
 244
 245 static void msi_domain_update_dom_ops(struct msi_domain_info *info)
 246 {
 247         struct msi_domain_ops *ops = info->ops;
 248
 249         if (ops == NULL) {
 250                 info->ops = &msi_domain_ops_default;
 251                 return;
 252         }
 253
 254         if (ops->get_hwirq == NULL)
 255                 ops->get_hwirq = msi_domain_ops_default.get_hwirq;
 256         if (ops->msi_init == NULL)
 257                 ops->msi_init = msi_domain_ops_default.msi_init;
 258         if (ops->msi_check == NULL)
 259                 ops->msi_check = msi_domain_ops_default.msi_check;
 260         if (ops->msi_prepare == NULL)
 261                 ops->msi_prepare = msi_domain_ops_default.msi_prepare;
 262         if (ops->set_desc == NULL)
 263                 ops->set_desc = msi_domain_ops_default.set_desc;
 264 }
 265
 266 static void msi_domain_update_chip_ops(struct msi_domain_info *info)
 267 {
 268         struct irq_chip *chip = info->chip;
 269
 270         BUG_ON(!chip || !chip->irq_mask || !chip->irq_unmask);
 271         if (!chip->irq_set_affinity)
 272                 chip->irq_set_affinity = msi_domain_set_affinity;
 273 }
 274
 275 /**
 276  * msi_create_irq_domain - Create a MSI interrupt domain
 277  * @fwnode:     Optional fwnode of the interrupt controller
 278  * @info:       MSI domain info
 279  * @parent:     Parent irq domain
 280  */
 281 struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode,
 282                                          struct msi_domain_info *info,
 283                                          struct irq_domain *parent)
 284 {
 285         struct irq_domain *domain;
 286
 287         if (info->flags & MSI_FLAG_USE_DEF_DOM_OPS)
 288                 msi_domain_update_dom_ops(info);
 289         if (info->flags & MSI_FLAG_USE_DEF_CHIP_OPS)
 290                 msi_domain_update_chip_ops(info);
 291
 292         domain = irq_domain_create_hierarchy(parent, IRQ_DOMAIN_FLAG_MSI, 0,
 293                                              fwnode, &msi_domain_ops, info);
 294
 295         if (domain && !domain->name && info->chip)
 296                 domain->name = info->chip->name;
 297
 298         return domain;
 299 }
 300
 301 int msi_domain_prepare_irqs(struct irq_domain *domain, struct device *dev,
 302                             int nvec, msi_alloc_info_t *arg)
 303 {
 304         struct msi_domain_info *info = domain->host_data;
 305         struct msi_domain_ops *ops = info->ops;
 306         int ret;
 307
 308         ret = ops->msi_check(domain, info, dev);
 309         if (ret == 0)
 310                 ret = ops->msi_prepare(domain, dev, nvec, arg);
 311
 312         return ret;
 313 }
 314
 315 int msi_domain_populate_irqs(struct irq_domain *domain, struct device *dev,
 316                              int virq, int nvec, msi_alloc_info_t *arg)
 317 {
 318         struct msi_domain_info *info = domain->host_data;
 319         struct msi_domain_ops *ops = info->ops;
 320         struct msi_desc *desc;
 321         int ret = 0;
 322
 323         for_each_msi_entry(desc, dev) {
 324                 /* Don't even try the multi-MSI brain damage. */
 325                 if (WARN_ON(!desc->irq || desc->nvec_used != 1)) {
 326                         ret = -EINVAL;
 327                         break;
 328                 }
 329
 330                 if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 331                         continue;
 332
 333                 ops->set_desc(arg, desc);
 334                 /* Assumes the domain mutex is held! */
 335                 ret = irq_domain_alloc_irqs_hierarchy(domain, desc->irq, 1,
 336                                                       arg);
 337                 if (ret)
 338                         break;
 339
 340                 irq_set_msi_desc_off(desc->irq, 0, desc);
 341         }
 342
 343         if (ret) {
 344                 /* Mop up the damage */
 345                 for_each_msi_entry(desc, dev) {
 346                         if (!(desc->irq >= virq && desc->irq < (virq + nvec)))
 347                                 continue;
 348
 349                         irq_domain_free_irqs_common(domain, desc->irq, 1);
 350                 }
 351         }
 352
 353         return ret;
 354 }
 355
 356 /*
 357  * Carefully check whether the device can use reservation mode. If
 358  * reservation mode is enabled then the early activation will assign a
 359  * dummy vector to the device. If the PCI/MSI device does not support
 360  * masking of the entry then this can result in spurious interrupts when
 361  * the device driver is not absolutely careful. But even then a malfunction
 362  * of the hardware could result in a spurious interrupt on the dummy vector
 363  * and render the device unusable. If the entry can be masked then the core
 364  * logic will prevent the spurious interrupt and reservation mode can be
 365  * used. For now reservation mode is restricted to PCI/MSI.
 366  */
 367 static bool msi_check_reservation_mode(struct irq_domain *domain,
 368                                        struct msi_domain_info *info,
 369                                        struct device *dev)
 370 {
 371         struct msi_desc *desc;
 372
 373         if (domain->bus_token != DOMAIN_BUS_PCI_MSI)
 374                 return false;
 375
 376         if (!(info->flags & MSI_FLAG_MUST_REACTIVATE))
 377                 return false;
 378
 379         if (IS_ENABLED(CONFIG_PCI_MSI) && pci_msi_ignore_mask)
 380                 return false;
 381
 382         /*
 383          * Checking the first MSI descriptor is sufficient. MSIX supports
 384          * masking and MSI does so when the maskbit is set.
 385          */
 386         desc = first_msi_entry(dev);
 387         return desc->msi_attrib.is_msix || desc->msi_attrib.maskbit;
 388 }
 389
 390 /**
 391  * msi_domain_alloc_irqs - Allocate interrupts from a MSI interrupt domain
 392  * @domain:     The domain to allocate from
 393  * @dev:        Pointer to device struct of the device for which the interrupts
 394  *              are allocated
 395  * @nvec:       The number of interrupts to allocate
 396  *
 397  * Returns 0 on success or an error code.
 398  */
 399 int msi_domain_alloc_irqs(struct irq_domain *domain, struct device *dev,
 400                           int nvec)
 401 {
 402         struct msi_domain_info *info = domain->host_data;
 403         struct msi_domain_ops *ops = info->ops;
 404         struct irq_data *irq_data;
 405         struct msi_desc *desc;
 406         msi_alloc_info_t arg;
 407         int i, ret, virq;
 408         bool can_reserve;
 409
 410         ret = msi_domain_prepare_irqs(domain, dev, nvec, &arg);
 411         if (ret)
 412                 return ret;
 413
 414         for_each_msi_entry(desc, dev) {
 415                 ops->set_desc(&arg, desc);
 416
 417                 virq = __irq_domain_alloc_irqs(domain, -1, desc->nvec_used,
 418                                                dev_to_node(dev), &arg, false,
 419                                                desc->affinity);
 420                 if (virq < 0) {
 421                         ret = -ENOSPC;
 422                         if (ops->handle_error)
 423                                 ret = ops->handle_error(domain, desc, ret);
 424                         if (ops->msi_finish)
 425                                 ops->msi_finish(&arg, ret);
 426                         return ret;
 427                 }
 428
 429                 for (i = 0; i < desc->nvec_used; i++) {
 430                         irq_set_msi_desc_off(virq, i, desc);
 431                         irq_debugfs_copy_devname(virq + i, dev);
 432                 }
 433         }
 434
 435         if (ops->msi_finish)
 436                 ops->msi_finish(&arg, 0);
 437
 438         can_reserve = msi_check_reservation_mode(domain, info, dev);
 439
 440         for_each_msi_entry(desc, dev) {
 441                 virq = desc->irq;
 442                 if (desc->nvec_used == 1)
 443                         dev_dbg(dev, "irq %d for MSI\n", virq);
 444                 else
 445                         dev_dbg(dev, "irq [%d-%d] for MSI\n",
 446                                 virq, virq + desc->nvec_used - 1);
 447                 /*
 448                  * This flag is set by the PCI layer as we need to activate
 449                  * the MSI entries before the PCI layer enables MSI in the
 450                  * card. Otherwise the card latches a random msi message.
 451                  */
 452                 if (!(info->flags & MSI_FLAG_ACTIVATE_EARLY))
 453                         continue;
 454
 455                 irq_data = irq_domain_get_irq_data(domain, desc->irq);
 456                 if (!can_reserve)
 457                         irqd_clr_can_reserve(irq_data);
 458                 ret = irq_domain_activate_irq(irq_data, can_reserve);
 459                 if (ret)
 460                         goto cleanup;
 461         }
 462
 463         /*
 464          * If these interrupts use reservation mode, clear the activated bit
 465          * so request_irq() will assign the final vector.
 466          */
 467         if (can_reserve) {
 468                 for_each_msi_entry(desc, dev) {
 469                         irq_data = irq_domain_get_irq_data(domain, desc->irq);
 470                         irqd_clr_activated(irq_data);
 471                 }
 472         }
 473         return 0;
 474
 475 cleanup:
 476         for_each_msi_entry(desc, dev) {
 477                 struct irq_data *irqd;
 478
 479                 if (desc->irq == virq)
 480                         break;
 481
 482                 irqd = irq_domain_get_irq_data(domain, desc->irq);
 483                 if (irqd_is_activated(irqd))
 484                         irq_domain_deactivate_irq(irqd);
 485         }
 486         msi_domain_free_irqs(domain, dev);
 487         return ret;
 488 }
 489
 490 /**
 491  * msi_domain_free_irqs - Free interrupts from a MSI interrupt @domain associated tp @dev
 492  * @domain:     The domain to managing the interrupts
 493  * @dev:        Pointer to device struct of the device for which the interrupts
 494  *              are free
 495  */
 496 void msi_domain_free_irqs(struct irq_domain *domain, struct device *dev)
 497 {
 498         struct msi_desc *desc;
 499
 500         for_each_msi_entry(desc, dev) {
 501                 /*
 502                  * We might have failed to allocate an MSI early
 503                  * enough that there is no IRQ associated to this
 504                  * entry. If that's the case, don't do anything.
 505                  */
 506                 if (desc->irq) {
 507                         irq_domain_free_irqs(desc->irq, desc->nvec_used);
 508                         desc->irq = 0;
 509                 }
 510         }
 511 }
 512
 513 /**
 514  * msi_get_domain_info - Get the MSI interrupt domain info for @domain
 515  * @domain:     The interrupt domain to retrieve data from
 516  *
 517  * Returns the pointer to the msi_domain_info stored in
 518  * @domain->host_data.
 519  */
 520 struct msi_domain_info *msi_get_domain_info(struct irq_domain *domain)
 521 {
 522         return (struct msi_domain_info *)domain->host_data;
 523 }
 524
 525 #endif /* CONFIG_GENERIC_MSI_IRQ_DOMAIN */