linux/drivers/pci/pcie/portdrv_core.c
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   1/*
   2 * File:        portdrv_core.c
   3 * Purpose:     PCI Express Port Bus Driver's Core Functions
   4 *
   5 * Copyright (C) 2004 Intel
   6 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/pci.h>
  11#include <linux/kernel.h>
  12#include <linux/errno.h>
  13#include <linux/pm.h>
  14#include <linux/string.h>
  15#include <linux/slab.h>
  16#include <linux/pcieport_if.h>
  17#include <linux/aer.h>
  18
  19#include "../pci.h"
  20#include "portdrv.h"
  21
  22/**
  23 * release_pcie_device - free PCI Express port service device structure
  24 * @dev: Port service device to release
  25 *
  26 * Invoked automatically when device is being removed in response to
  27 * device_unregister(dev).  Release all resources being claimed.
  28 */
  29static void release_pcie_device(struct device *dev)
  30{
  31        kfree(to_pcie_device(dev));
  32}
  33
  34/**
  35 * pcie_port_msix_add_entry - add entry to given array of MSI-X entries
  36 * @entries: Array of MSI-X entries
  37 * @new_entry: Index of the entry to add to the array
  38 * @nr_entries: Number of entries aleady in the array
  39 *
  40 * Return value: Position of the added entry in the array
  41 */
  42static int pcie_port_msix_add_entry(
  43        struct msix_entry *entries, int new_entry, int nr_entries)
  44{
  45        int j;
  46
  47        for (j = 0; j < nr_entries; j++)
  48                if (entries[j].entry == new_entry)
  49                        return j;
  50
  51        entries[j].entry = new_entry;
  52        return j;
  53}
  54
  55/**
  56 * pcie_port_enable_msix - try to set up MSI-X as interrupt mode for given port
  57 * @dev: PCI Express port to handle
  58 * @vectors: Array of interrupt vectors to populate
  59 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
  60 *
  61 * Return value: 0 on success, error code on failure
  62 */
  63static int pcie_port_enable_msix(struct pci_dev *dev, int *vectors, int mask)
  64{
  65        struct msix_entry *msix_entries;
  66        int idx[PCIE_PORT_DEVICE_MAXSERVICES];
  67        int nr_entries, status, pos, i, nvec;
  68        u16 reg16;
  69        u32 reg32;
  70
  71        nr_entries = pci_msix_table_size(dev);
  72        if (!nr_entries)
  73                return -EINVAL;
  74        if (nr_entries > PCIE_PORT_MAX_MSIX_ENTRIES)
  75                nr_entries = PCIE_PORT_MAX_MSIX_ENTRIES;
  76
  77        msix_entries = kzalloc(sizeof(*msix_entries) * nr_entries, GFP_KERNEL);
  78        if (!msix_entries)
  79                return -ENOMEM;
  80
  81        /*
  82         * Allocate as many entries as the port wants, so that we can check
  83         * which of them will be useful.  Moreover, if nr_entries is correctly
  84         * equal to the number of entries this port actually uses, we'll happily
  85         * go through without any tricks.
  86         */
  87        for (i = 0; i < nr_entries; i++)
  88                msix_entries[i].entry = i;
  89
  90        status = pci_enable_msix(dev, msix_entries, nr_entries);
  91        if (status)
  92                goto Exit;
  93
  94        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
  95                idx[i] = -1;
  96        status = -EIO;
  97        nvec = 0;
  98
  99        if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
 100                int entry;
 101
 102                /*
 103                 * The code below follows the PCI Express Base Specification 2.0
 104                 * stating in Section 6.1.6 that "PME and Hot-Plug Event
 105                 * interrupts (when both are implemented) always share the same
 106                 * MSI or MSI-X vector, as indicated by the Interrupt Message
 107                 * Number field in the PCI Express Capabilities register", where
 108                 * according to Section 7.8.2 of the specification "For MSI-X,
 109                 * the value in this field indicates which MSI-X Table entry is
 110                 * used to generate the interrupt message."
 111                 */
 112                pos = pci_pcie_cap(dev);
 113                pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &reg16);
 114                entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
 115                if (entry >= nr_entries)
 116                        goto Error;
 117
 118                i = pcie_port_msix_add_entry(msix_entries, entry, nvec);
 119                if (i == nvec)
 120                        nvec++;
 121
 122                idx[PCIE_PORT_SERVICE_PME_SHIFT] = i;
 123                idx[PCIE_PORT_SERVICE_HP_SHIFT] = i;
 124        }
 125
 126        if (mask & PCIE_PORT_SERVICE_AER) {
 127                int entry;
 128
 129                /*
 130                 * The code below follows Section 7.10.10 of the PCI Express
 131                 * Base Specification 2.0 stating that bits 31-27 of the Root
 132                 * Error Status Register contain a value indicating which of the
 133                 * MSI/MSI-X vectors assigned to the port is going to be used
 134                 * for AER, where "For MSI-X, the value in this register
 135                 * indicates which MSI-X Table entry is used to generate the
 136                 * interrupt message."
 137                 */
 138                pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
 139                pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &reg32);
 140                entry = reg32 >> 27;
 141                if (entry >= nr_entries)
 142                        goto Error;
 143
 144                i = pcie_port_msix_add_entry(msix_entries, entry, nvec);
 145                if (i == nvec)
 146                        nvec++;
 147
 148                idx[PCIE_PORT_SERVICE_AER_SHIFT] = i;
 149        }
 150
 151        /*
 152         * If nvec is equal to the allocated number of entries, we can just use
 153         * what we have.  Otherwise, the port has some extra entries not for the
 154         * services we know and we need to work around that.
 155         */
 156        if (nvec == nr_entries) {
 157                status = 0;
 158        } else {
 159                /* Drop the temporary MSI-X setup */
 160                pci_disable_msix(dev);
 161
 162                /* Now allocate the MSI-X vectors for real */
 163                status = pci_enable_msix(dev, msix_entries, nvec);
 164                if (status)
 165                        goto Exit;
 166        }
 167
 168        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 169                vectors[i] = idx[i] >= 0 ? msix_entries[idx[i]].vector : -1;
 170
 171 Exit:
 172        kfree(msix_entries);
 173        return status;
 174
 175 Error:
 176        pci_disable_msix(dev);
 177        goto Exit;
 178}
 179
 180/**
 181 * init_service_irqs - initialize irqs for PCI Express port services
 182 * @dev: PCI Express port to handle
 183 * @irqs: Array of irqs to populate
 184 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 185 *
 186 * Return value: Interrupt mode associated with the port
 187 */
 188static int init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
 189{
 190        int i, irq = -1;
 191
 192        /* We have to use INTx if MSI cannot be used for PCIe PME. */
 193        if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi()) {
 194                if (dev->pin)
 195                        irq = dev->irq;
 196                goto no_msi;
 197        }
 198
 199        /* Try to use MSI-X if supported */
 200        if (!pcie_port_enable_msix(dev, irqs, mask))
 201                return 0;
 202
 203        /* We're not going to use MSI-X, so try MSI and fall back to INTx */
 204        if (!pci_enable_msi(dev) || dev->pin)
 205                irq = dev->irq;
 206
 207 no_msi:
 208        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
 209                irqs[i] = irq;
 210        irqs[PCIE_PORT_SERVICE_VC_SHIFT] = -1;
 211
 212        if (irq < 0)
 213                return -ENODEV;
 214        return 0;
 215}
 216
 217static void cleanup_service_irqs(struct pci_dev *dev)
 218{
 219        if (dev->msix_enabled)
 220                pci_disable_msix(dev);
 221        else if (dev->msi_enabled)
 222                pci_disable_msi(dev);
 223}
 224
 225/**
 226 * get_port_device_capability - discover capabilities of a PCI Express port
 227 * @dev: PCI Express port to examine
 228 *
 229 * The capabilities are read from the port's PCI Express configuration registers
 230 * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
 231 * 7.9 - 7.11.
 232 *
 233 * Return value: Bitmask of discovered port capabilities
 234 */
 235static int get_port_device_capability(struct pci_dev *dev)
 236{
 237        int services = 0, pos;
 238        u16 reg16;
 239        u32 reg32;
 240        int cap_mask;
 241        int err;
 242
 243        if (pcie_ports_disabled)
 244                return 0;
 245
 246        err = pcie_port_platform_notify(dev, &cap_mask);
 247        if (!pcie_ports_auto) {
 248                cap_mask = PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP
 249                                | PCIE_PORT_SERVICE_VC;
 250                if (pci_aer_available())
 251                        cap_mask |= PCIE_PORT_SERVICE_AER;
 252        } else if (err) {
 253                        return 0;
 254        }
 255
 256        pos = pci_pcie_cap(dev);
 257        pci_read_config_word(dev, pos + PCI_EXP_FLAGS, &reg16);
 258        /* Hot-Plug Capable */
 259        if ((cap_mask & PCIE_PORT_SERVICE_HP) && (reg16 & PCI_EXP_FLAGS_SLOT)) {
 260                pci_read_config_dword(dev, pos + PCI_EXP_SLTCAP, &reg32);
 261                if (reg32 & PCI_EXP_SLTCAP_HPC) {
 262                        services |= PCIE_PORT_SERVICE_HP;
 263                        /*
 264                         * Disable hot-plug interrupts in case they have been
 265                         * enabled by the BIOS and the hot-plug service driver
 266                         * is not loaded.
 267                         */
 268                        pos += PCI_EXP_SLTCTL;
 269                        pci_read_config_word(dev, pos, &reg16);
 270                        reg16 &= ~(PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
 271                        pci_write_config_word(dev, pos, reg16);
 272                }
 273        }
 274        /* AER capable */
 275        if ((cap_mask & PCIE_PORT_SERVICE_AER)
 276            && pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR)) {
 277                services |= PCIE_PORT_SERVICE_AER;
 278                /*
 279                 * Disable AER on this port in case it's been enabled by the
 280                 * BIOS (the AER service driver will enable it when necessary).
 281                 */
 282                pci_disable_pcie_error_reporting(dev);
 283        }
 284        /* VC support */
 285        if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VC))
 286                services |= PCIE_PORT_SERVICE_VC;
 287        /* Root ports are capable of generating PME too */
 288        if ((cap_mask & PCIE_PORT_SERVICE_PME)
 289            && dev->pcie_type == PCI_EXP_TYPE_ROOT_PORT) {
 290                services |= PCIE_PORT_SERVICE_PME;
 291                /*
 292                 * Disable PME interrupt on this port in case it's been enabled
 293                 * by the BIOS (the PME service driver will enable it when
 294                 * necessary).
 295                 */
 296                pcie_pme_interrupt_enable(dev, false);
 297        }
 298
 299        return services;
 300}
 301
 302/**
 303 * pcie_device_init - allocate and initialize PCI Express port service device
 304 * @pdev: PCI Express port to associate the service device with
 305 * @service: Type of service to associate with the service device
 306 * @irq: Interrupt vector to associate with the service device
 307 */
 308static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
 309{
 310        int retval;
 311        struct pcie_device *pcie;
 312        struct device *device;
 313
 314        pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
 315        if (!pcie)
 316                return -ENOMEM;
 317        pcie->port = pdev;
 318        pcie->irq = irq;
 319        pcie->service = service;
 320
 321        /* Initialize generic device interface */
 322        device = &pcie->device;
 323        device->bus = &pcie_port_bus_type;
 324        device->release = release_pcie_device;  /* callback to free pcie dev */
 325        dev_set_name(device, "%s:pcie%02x",
 326                     pci_name(pdev),
 327                     get_descriptor_id(pdev->pcie_type, service));
 328        device->parent = &pdev->dev;
 329        device_enable_async_suspend(device);
 330
 331        retval = device_register(device);
 332        if (retval)
 333                kfree(pcie);
 334        else
 335                get_device(device);
 336        return retval;
 337}
 338
 339/**
 340 * pcie_port_device_register - register PCI Express port
 341 * @dev: PCI Express port to register
 342 *
 343 * Allocate the port extension structure and register services associated with
 344 * the port.
 345 */
 346int pcie_port_device_register(struct pci_dev *dev)
 347{
 348        int status, capabilities, i, nr_service;
 349        int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
 350
 351        /* Enable PCI Express port device */
 352        status = pci_enable_device(dev);
 353        if (status)
 354                return status;
 355
 356        /* Get and check PCI Express port services */
 357        capabilities = get_port_device_capability(dev);
 358        if (!capabilities)
 359                return 0;
 360
 361        pci_set_master(dev);
 362        /*
 363         * Initialize service irqs. Don't use service devices that
 364         * require interrupts if there is no way to generate them.
 365         */
 366        status = init_service_irqs(dev, irqs, capabilities);
 367        if (status) {
 368                capabilities &= PCIE_PORT_SERVICE_VC;
 369                if (!capabilities)
 370                        goto error_disable;
 371        }
 372
 373        /* Allocate child services if any */
 374        status = -ENODEV;
 375        nr_service = 0;
 376        for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
 377                int service = 1 << i;
 378                if (!(capabilities & service))
 379                        continue;
 380                if (!pcie_device_init(dev, service, irqs[i]))
 381                        nr_service++;
 382        }
 383        if (!nr_service)
 384                goto error_cleanup_irqs;
 385
 386        return 0;
 387
 388error_cleanup_irqs:
 389        cleanup_service_irqs(dev);
 390error_disable:
 391        pci_disable_device(dev);
 392        return status;
 393}
 394
 395#ifdef CONFIG_PM
 396static int suspend_iter(struct device *dev, void *data)
 397{
 398        struct pcie_port_service_driver *service_driver;
 399
 400        if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
 401                service_driver = to_service_driver(dev->driver);
 402                if (service_driver->suspend)
 403                        service_driver->suspend(to_pcie_device(dev));
 404        }
 405        return 0;
 406}
 407
 408/**
 409 * pcie_port_device_suspend - suspend port services associated with a PCIe port
 410 * @dev: PCI Express port to handle
 411 */
 412int pcie_port_device_suspend(struct device *dev)
 413{
 414        return device_for_each_child(dev, NULL, suspend_iter);
 415}
 416
 417static int resume_iter(struct device *dev, void *data)
 418{
 419        struct pcie_port_service_driver *service_driver;
 420
 421        if ((dev->bus == &pcie_port_bus_type) &&
 422            (dev->driver)) {
 423                service_driver = to_service_driver(dev->driver);
 424                if (service_driver->resume)
 425                        service_driver->resume(to_pcie_device(dev));
 426        }
 427        return 0;
 428}
 429
 430/**
 431 * pcie_port_device_suspend - resume port services associated with a PCIe port
 432 * @dev: PCI Express port to handle
 433 */
 434int pcie_port_device_resume(struct device *dev)
 435{
 436        return device_for_each_child(dev, NULL, resume_iter);
 437}
 438#endif /* PM */
 439
 440static int remove_iter(struct device *dev, void *data)
 441{
 442        if (dev->bus == &pcie_port_bus_type) {
 443                put_device(dev);
 444                device_unregister(dev);
 445        }
 446        return 0;
 447}
 448
 449/**
 450 * pcie_port_device_remove - unregister PCI Express port service devices
 451 * @dev: PCI Express port the service devices to unregister are associated with
 452 *
 453 * Remove PCI Express port service devices associated with given port and
 454 * disable MSI-X or MSI for the port.
 455 */
 456void pcie_port_device_remove(struct pci_dev *dev)
 457{
 458        device_for_each_child(&dev->dev, NULL, remove_iter);
 459        cleanup_service_irqs(dev);
 460        pci_disable_device(dev);
 461}
 462
 463/**
 464 * pcie_port_probe_service - probe driver for given PCI Express port service
 465 * @dev: PCI Express port service device to probe against
 466 *
 467 * If PCI Express port service driver is registered with
 468 * pcie_port_service_register(), this function will be called by the driver core
 469 * whenever match is found between the driver and a port service device.
 470 */
 471static int pcie_port_probe_service(struct device *dev)
 472{
 473        struct pcie_device *pciedev;
 474        struct pcie_port_service_driver *driver;
 475        int status;
 476
 477        if (!dev || !dev->driver)
 478                return -ENODEV;
 479
 480        driver = to_service_driver(dev->driver);
 481        if (!driver || !driver->probe)
 482                return -ENODEV;
 483
 484        pciedev = to_pcie_device(dev);
 485        status = driver->probe(pciedev);
 486        if (!status) {
 487                dev_printk(KERN_DEBUG, dev, "service driver %s loaded\n",
 488                        driver->name);
 489                get_device(dev);
 490        }
 491        return status;
 492}
 493
 494/**
 495 * pcie_port_remove_service - detach driver from given PCI Express port service
 496 * @dev: PCI Express port service device to handle
 497 *
 498 * If PCI Express port service driver is registered with
 499 * pcie_port_service_register(), this function will be called by the driver core
 500 * when device_unregister() is called for the port service device associated
 501 * with the driver.
 502 */
 503static int pcie_port_remove_service(struct device *dev)
 504{
 505        struct pcie_device *pciedev;
 506        struct pcie_port_service_driver *driver;
 507
 508        if (!dev || !dev->driver)
 509                return 0;
 510
 511        pciedev = to_pcie_device(dev);
 512        driver = to_service_driver(dev->driver);
 513        if (driver && driver->remove) {
 514                dev_printk(KERN_DEBUG, dev, "unloading service driver %s\n",
 515                        driver->name);
 516                driver->remove(pciedev);
 517                put_device(dev);
 518        }
 519        return 0;
 520}
 521
 522/**
 523 * pcie_port_shutdown_service - shut down given PCI Express port service
 524 * @dev: PCI Express port service device to handle
 525 *
 526 * If PCI Express port service driver is registered with
 527 * pcie_port_service_register(), this function will be called by the driver core
 528 * when device_shutdown() is called for the port service device associated
 529 * with the driver.
 530 */
 531static void pcie_port_shutdown_service(struct device *dev) {}
 532
 533/**
 534 * pcie_port_service_register - register PCI Express port service driver
 535 * @new: PCI Express port service driver to register
 536 */
 537int pcie_port_service_register(struct pcie_port_service_driver *new)
 538{
 539        if (pcie_ports_disabled)
 540                return -ENODEV;
 541
 542        new->driver.name = (char *)new->name;
 543        new->driver.bus = &pcie_port_bus_type;
 544        new->driver.probe = pcie_port_probe_service;
 545        new->driver.remove = pcie_port_remove_service;
 546        new->driver.shutdown = pcie_port_shutdown_service;
 547
 548        return driver_register(&new->driver);
 549}
 550EXPORT_SYMBOL(pcie_port_service_register);
 551
 552/**
 553 * pcie_port_service_unregister - unregister PCI Express port service driver
 554 * @drv: PCI Express port service driver to unregister
 555 */
 556void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
 557{
 558        driver_unregister(&drv->driver);
 559}
 560EXPORT_SYMBOL(pcie_port_service_unregister);
 561