drivers/ntb/msi.c

   1 // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
   2
   3 #include <linux/irq.h>
   4 #include <linux/module.h>
   5 #include <linux/ntb.h>
   6 #include <linux/msi.h>
   7 #include <linux/pci.h>
   8
   9 struct ntb_msi {
  10         u64 base_addr;
  11         u64 end_addr;
  12
  13         void (*desc_changed)(void *ctx);
  14
  15         u32 __iomem *peer_mws[];
  16 };
  17
  18 /**
  19  * ntb_msi_init() - Initialize the MSI context
  20  * @ntb:        NTB device context
  21  *
  22  * This function must be called before any other ntb_msi function.
  23  * It initializes the context for MSI operations and maps
  24  * the peer memory windows.
  25  *
  26  * This function reserves the last N outbound memory windows (where N
  27  * is the number of peers).
  28  *
  29  * Return: Zero on success, otherwise a negative error number.
  30  */
  31 int ntb_msi_init(struct ntb_dev *ntb,
  32                  void (*desc_changed)(void *ctx))
  33 {
  34         phys_addr_t mw_phys_addr;
  35         resource_size_t mw_size;
  36         size_t struct_size;
  37         int peer_widx;
  38         int peers;
  39         int ret;
  40         int i;
  41
  42         peers = ntb_peer_port_count(ntb);
  43         if (peers <= 0)
  44                 return -EINVAL;
  45
  46         struct_size = sizeof(*ntb->msi) + sizeof(*ntb->msi->peer_mws) * peers;
  47
  48         ntb->msi = devm_kzalloc(&ntb->dev, struct_size, GFP_KERNEL);
  49         if (!ntb->msi)
  50                 return -ENOMEM;
  51
  52         ntb->msi->desc_changed = desc_changed;
  53
  54         for (i = 0; i < peers; i++) {
  55                 peer_widx = ntb_peer_mw_count(ntb) - 1 - i;
  56
  57                 ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr,
  58                                            &mw_size);
  59                 if (ret)
  60                         goto unroll;
  61
  62                 ntb->msi->peer_mws[i] = devm_ioremap(&ntb->dev, mw_phys_addr,
  63                                                      mw_size);
  64                 if (!ntb->msi->peer_mws[i]) {
  65                         ret = -EFAULT;
  66                         goto unroll;
  67                 }
  68         }
  69
  70         return 0;
  71
  72 unroll:
  73         for (i = 0; i < peers; i++)
  74                 if (ntb->msi->peer_mws[i])
  75                         devm_iounmap(&ntb->dev, ntb->msi->peer_mws[i]);
  76
  77         devm_kfree(&ntb->dev, ntb->msi);
  78         ntb->msi = NULL;
  79         return ret;
  80 }
  81 EXPORT_SYMBOL(ntb_msi_init);
  82
  83 /**
  84  * ntb_msi_setup_mws() - Initialize the MSI inbound memory windows
  85  * @ntb:        NTB device context
  86  *
  87  * This function sets up the required inbound memory windows. It should be
  88  * called from a work function after a link up event.
  89  *
  90  * Over the entire network, this function will reserves the last N
  91  * inbound memory windows for each peer (where N is the number of peers).
  92  *
  93  * ntb_msi_init() must be called before this function.
  94  *
  95  * Return: Zero on success, otherwise a negative error number.
  96  */
  97 int ntb_msi_setup_mws(struct ntb_dev *ntb)
  98 {
  99         struct msi_desc *desc;
 100         u64 addr;
 101         int peer, peer_widx;
 102         resource_size_t addr_align, size_align, size_max;
 103         resource_size_t mw_size = SZ_32K;
 104         resource_size_t mw_min_size = mw_size;
 105         int i;
 106         int ret;
 107
 108         if (!ntb->msi)
 109                 return -EINVAL;
 110
 111         desc = first_msi_entry(&ntb->pdev->dev);
 112         addr = desc->msg.address_lo + ((uint64_t)desc->msg.address_hi << 32);
 113
 114         for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
 115                 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
 116                 if (peer_widx < 0)
 117                         return peer_widx;
 118
 119                 ret = ntb_mw_get_align(ntb, peer, peer_widx, &addr_align,
 120                                        NULL, NULL);
 121                 if (ret)
 122                         return ret;
 123
 124                 addr &= ~(addr_align - 1);
 125         }
 126
 127         for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
 128                 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
 129                 if (peer_widx < 0) {
 130                         ret = peer_widx;
 131                         goto error_out;
 132                 }
 133
 134                 ret = ntb_mw_get_align(ntb, peer, peer_widx, NULL,
 135                                        &size_align, &size_max);
 136                 if (ret)
 137                         goto error_out;
 138
 139                 mw_size = round_up(mw_size, size_align);
 140                 mw_size = max(mw_size, size_max);
 141                 if (mw_size < mw_min_size)
 142                         mw_min_size = mw_size;
 143
 144                 ret = ntb_mw_set_trans(ntb, peer, peer_widx,
 145                                        addr, mw_size);
 146                 if (ret)
 147                         goto error_out;
 148         }
 149
 150         ntb->msi->base_addr = addr;
 151         ntb->msi->end_addr = addr + mw_min_size;
 152
 153         return 0;
 154
 155 error_out:
 156         for (i = 0; i < peer; i++) {
 157                 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
 158                 if (peer_widx < 0)
 159                         continue;
 160
 161                 ntb_mw_clear_trans(ntb, i, peer_widx);
 162         }
 163
 164         return ret;
 165 }
 166 EXPORT_SYMBOL(ntb_msi_setup_mws);
 167
 168 /**
 169  * ntb_msi_clear_mws() - Clear all inbound memory windows
 170  * @ntb:        NTB device context
 171  *
 172  * This function tears down the resources used by ntb_msi_setup_mws().
 173  */
 174 void ntb_msi_clear_mws(struct ntb_dev *ntb)
 175 {
 176         int peer;
 177         int peer_widx;
 178
 179         for (peer = 0; peer < ntb_peer_port_count(ntb); peer++) {
 180                 peer_widx = ntb_peer_highest_mw_idx(ntb, peer);
 181                 if (peer_widx < 0)
 182                         continue;
 183
 184                 ntb_mw_clear_trans(ntb, peer, peer_widx);
 185         }
 186 }
 187 EXPORT_SYMBOL(ntb_msi_clear_mws);
 188
 189 struct ntb_msi_devres {
 190         struct ntb_dev *ntb;
 191         struct msi_desc *entry;
 192         struct ntb_msi_desc *msi_desc;
 193 };
 194
 195 static int ntb_msi_set_desc(struct ntb_dev *ntb, struct msi_desc *entry,
 196                             struct ntb_msi_desc *msi_desc)
 197 {
 198         u64 addr;
 199
 200         addr = entry->msg.address_lo +
 201                 ((uint64_t)entry->msg.address_hi << 32);
 202
 203         if (addr < ntb->msi->base_addr || addr >= ntb->msi->end_addr) {
 204                 dev_warn_once(&ntb->dev,
 205                               "IRQ %d: MSI Address not within the memory window (%llx, [%llx %llx])\n",
 206                               entry->irq, addr, ntb->msi->base_addr,
 207                               ntb->msi->end_addr);
 208                 return -EFAULT;
 209         }
 210
 211         msi_desc->addr_offset = addr - ntb->msi->base_addr;
 212         msi_desc->data = entry->msg.data;
 213
 214         return 0;
 215 }
 216
 217 static void ntb_msi_write_msg(struct msi_desc *entry, void *data)
 218 {
 219         struct ntb_msi_devres *dr = data;
 220
 221         WARN_ON(ntb_msi_set_desc(dr->ntb, entry, dr->msi_desc));
 222
 223         if (dr->ntb->msi->desc_changed)
 224                 dr->ntb->msi->desc_changed(dr->ntb->ctx);
 225 }
 226
 227 static void ntbm_msi_callback_release(struct device *dev, void *res)
 228 {
 229         struct ntb_msi_devres *dr = res;
 230
 231         dr->entry->write_msi_msg = NULL;
 232         dr->entry->write_msi_msg_data = NULL;
 233 }
 234
 235 static int ntbm_msi_setup_callback(struct ntb_dev *ntb, struct msi_desc *entry,
 236                                    struct ntb_msi_desc *msi_desc)
 237 {
 238         struct ntb_msi_devres *dr;
 239
 240         dr = devres_alloc(ntbm_msi_callback_release,
 241                           sizeof(struct ntb_msi_devres), GFP_KERNEL);
 242         if (!dr)
 243                 return -ENOMEM;
 244
 245         dr->ntb = ntb;
 246         dr->entry = entry;
 247         dr->msi_desc = msi_desc;
 248
 249         devres_add(&ntb->dev, dr);
 250
 251         dr->entry->write_msi_msg = ntb_msi_write_msg;
 252         dr->entry->write_msi_msg_data = dr;
 253
 254         return 0;
 255 }
 256
 257 /**
 258  * ntbm_msi_request_threaded_irq() - allocate an MSI interrupt
 259  * @ntb:        NTB device context
 260  * @handler:    Function to be called when the IRQ occurs
 261  * @thread_fn:  Function to be called in a threaded interrupt context. NULL
 262  *              for clients which handle everything in @handler
 263  * @devname:    An ascii name for the claiming device, dev_name(dev) if NULL
 264  * @dev_id:     A cookie passed back to the handler function
 265  *
 266  * This function assigns an interrupt handler to an unused
 267  * MSI interrupt and returns the descriptor used to trigger
 268  * it. The descriptor can then be sent to a peer to trigger
 269  * the interrupt.
 270  *
 271  * The interrupt resource is managed with devres so it will
 272  * be automatically freed when the NTB device is torn down.
 273  *
 274  * If an IRQ allocated with this function needs to be freed
 275  * separately, ntbm_free_irq() must be used.
 276  *
 277  * Return: IRQ number assigned on success, otherwise a negative error number.
 278  */
 279 int ntbm_msi_request_threaded_irq(struct ntb_dev *ntb, irq_handler_t handler,
 280                                   irq_handler_t thread_fn,
 281                                   const char *name, void *dev_id,
 282                                   struct ntb_msi_desc *msi_desc)
 283 {
 284         struct msi_desc *entry;
 285         int ret;
 286
 287         if (!ntb->msi)
 288                 return -EINVAL;
 289
 290         for_each_pci_msi_entry(entry, ntb->pdev) {
 291                 if (irq_has_action(entry->irq))
 292                         continue;
 293
 294                 ret = devm_request_threaded_irq(&ntb->dev, entry->irq, handler,
 295                                                 thread_fn, 0, name, dev_id);
 296                 if (ret)
 297                         continue;
 298
 299                 if (ntb_msi_set_desc(ntb, entry, msi_desc)) {
 300                         devm_free_irq(&ntb->dev, entry->irq, dev_id);
 301                         continue;
 302                 }
 303
 304                 ret = ntbm_msi_setup_callback(ntb, entry, msi_desc);
 305                 if (ret) {
 306                         devm_free_irq(&ntb->dev, entry->irq, dev_id);
 307                         return ret;
 308                 }
 309
 310
 311                 return entry->irq;
 312         }
 313
 314         return -ENODEV;
 315 }
 316 EXPORT_SYMBOL(ntbm_msi_request_threaded_irq);
 317
 318 static int ntbm_msi_callback_match(struct device *dev, void *res, void *data)
 319 {
 320         struct ntb_dev *ntb = dev_ntb(dev);
 321         struct ntb_msi_devres *dr = res;
 322
 323         return dr->ntb == ntb && dr->entry == data;
 324 }
 325
 326 /**
 327  * ntbm_msi_free_irq() - free an interrupt
 328  * @ntb:        NTB device context
 329  * @irq:        Interrupt line to free
 330  * @dev_id:     Device identity to free
 331  *
 332  * This function should be used to manually free IRQs allocated with
 333  * ntbm_request_[threaded_]irq().
 334  */
 335 void ntbm_msi_free_irq(struct ntb_dev *ntb, unsigned int irq, void *dev_id)
 336 {
 337         struct msi_desc *entry = irq_get_msi_desc(irq);
 338
 339         entry->write_msi_msg = NULL;
 340         entry->write_msi_msg_data = NULL;
 341
 342         WARN_ON(devres_destroy(&ntb->dev, ntbm_msi_callback_release,
 343                                ntbm_msi_callback_match, entry));
 344
 345         devm_free_irq(&ntb->dev, irq, dev_id);
 346 }
 347 EXPORT_SYMBOL(ntbm_msi_free_irq);
 348
 349 /**
 350  * ntb_msi_peer_trigger() - Trigger an interrupt handler on a peer
 351  * @ntb:        NTB device context
 352  * @peer:       Peer index
 353  * @desc:       MSI descriptor data which triggers the interrupt
 354  *
 355  * This function triggers an interrupt on a peer. It requires
 356  * the descriptor structure to have been passed from that peer
 357  * by some other means.
 358  *
 359  * Return: Zero on success, otherwise a negative error number.
 360  */
 361 int ntb_msi_peer_trigger(struct ntb_dev *ntb, int peer,
 362                          struct ntb_msi_desc *desc)
 363 {
 364         int idx;
 365
 366         if (!ntb->msi)
 367                 return -EINVAL;
 368
 369         idx = desc->addr_offset / sizeof(*ntb->msi->peer_mws[peer]);
 370
 371         iowrite32(desc->data, &ntb->msi->peer_mws[peer][idx]);
 372
 373         return 0;
 374 }
 375 EXPORT_SYMBOL(ntb_msi_peer_trigger);
 376
 377 /**
 378  * ntb_msi_peer_addr() - Get the DMA address to trigger a peer's MSI interrupt
 379  * @ntb:        NTB device context
 380  * @peer:       Peer index
 381  * @desc:       MSI descriptor data which triggers the interrupt
 382  * @msi_addr:   Physical address to trigger the interrupt
 383  *
 384  * This function allows using DMA engines to trigger an interrupt
 385  * (for example, trigger an interrupt to process the data after
 386  * sending it). To trigger the interrupt, write @desc.data to the address
 387  * returned in @msi_addr
 388  *
 389  * Return: Zero on success, otherwise a negative error number.
 390  */
 391 int ntb_msi_peer_addr(struct ntb_dev *ntb, int peer,
 392                       struct ntb_msi_desc *desc,
 393                       phys_addr_t *msi_addr)
 394 {
 395         int peer_widx = ntb_peer_mw_count(ntb) - 1 - peer;
 396         phys_addr_t mw_phys_addr;
 397         int ret;
 398
 399         ret = ntb_peer_mw_get_addr(ntb, peer_widx, &mw_phys_addr, NULL);
 400         if (ret)
 401                 return ret;
 402
 403         if (msi_addr)
 404                 *msi_addr = mw_phys_addr + desc->addr_offset;
 405
 406         return 0;
 407 }
 408 EXPORT_SYMBOL(ntb_msi_peer_addr);