1 // SPDX-License-Identifier: GPL-2.0
3 * Purpose: PCI Express Port Bus Driver's Core Functions
5 * Copyright (C) 2004 Intel
6 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
9 #include <linux/module.h>
10 #include <linux/pci.h>
11 #include <linux/kernel.h>
12 #include <linux/delay.h>
13 #include <linux/errno.h>
15 #include <linux/pm_runtime.h>
16 #include <linux/string.h>
17 #include <linux/slab.h>
18 #include <linux/aer.h>
23 struct portdrv_service_data {
24 struct pcie_port_service_driver *drv;
30 * release_pcie_device - free PCI Express port service device structure
31 * @dev: Port service device to release
33 * Invoked automatically when device is being removed in response to
34 * device_unregister(dev). Release all resources being claimed.
36 static void release_pcie_device(struct device *dev)
38 kfree(to_pcie_device(dev));
42 * Fill in *pme, *aer, *dpc with the relevant Interrupt Message Numbers if
43 * services are enabled in "mask". Return the number of MSI/MSI-X vectors
44 * required to accommodate the largest Message Number.
46 static int pcie_message_numbers(struct pci_dev *dev, int mask,
47 u32 *pme, u32 *aer, u32 *dpc)
53 * The Interrupt Message Number indicates which vector is used, i.e.,
54 * the MSI-X table entry or the MSI offset between the base Message
55 * Data and the generated interrupt message. See PCIe r3.1, sec
56 * 7.8.2, 7.10.10, 7.31.2.
59 if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
60 PCIE_PORT_SERVICE_BWNOTIF)) {
61 pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
62 *pme = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
67 if (mask & PCIE_PORT_SERVICE_AER) {
72 pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS,
74 *aer = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
75 nvec = max(nvec, *aer + 1);
80 if (mask & PCIE_PORT_SERVICE_DPC) {
81 pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
83 pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP,
85 *dpc = reg16 & PCI_EXP_DPC_IRQ;
86 nvec = max(nvec, *dpc + 1);
94 * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
96 * @dev: PCI Express port to handle
97 * @irqs: Array of interrupt vectors to populate
98 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
100 * Return value: 0 on success, error code on failure
102 static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
104 int nr_entries, nvec, pcie_irq;
105 u32 pme = 0, aer = 0, dpc = 0;
107 /* Allocate the maximum possible number of MSI/MSI-X vectors */
108 nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
109 PCI_IRQ_MSIX | PCI_IRQ_MSI);
113 /* See how many and which Interrupt Message Numbers we actually use */
114 nvec = pcie_message_numbers(dev, mask, &pme, &aer, &dpc);
115 if (nvec > nr_entries) {
116 pci_free_irq_vectors(dev);
121 * If we allocated more than we need, free them and reallocate fewer.
123 * Reallocating may change the specific vectors we get, so
124 * pci_irq_vector() must be done *after* the reallocation.
126 * If we're using MSI, hardware is *allowed* to change the Interrupt
127 * Message Numbers when we free and reallocate the vectors, but we
128 * assume it won't because we allocate enough vectors for the
129 * biggest Message Number we found.
131 if (nvec != nr_entries) {
132 pci_free_irq_vectors(dev);
134 nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
135 PCI_IRQ_MSIX | PCI_IRQ_MSI);
140 /* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
141 if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
142 PCIE_PORT_SERVICE_BWNOTIF)) {
143 pcie_irq = pci_irq_vector(dev, pme);
144 irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
145 irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
146 irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq;
149 if (mask & PCIE_PORT_SERVICE_AER)
150 irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, aer);
152 if (mask & PCIE_PORT_SERVICE_DPC)
153 irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, dpc);
159 * pcie_init_service_irqs - initialize irqs for PCI Express port services
160 * @dev: PCI Express port to handle
161 * @irqs: Array of irqs to populate
162 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
164 * Return value: Interrupt mode associated with the port
166 static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
170 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
174 * If we support PME but can't use MSI/MSI-X for it, we have to
175 * fall back to INTx or other interrupts, e.g., a system shared
178 if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
181 /* Try to use MSI-X or MSI if supported */
182 if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
186 /* fall back to legacy IRQ */
187 ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
191 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
192 irqs[i] = pci_irq_vector(dev, 0);
198 * get_port_device_capability - discover capabilities of a PCI Express port
199 * @dev: PCI Express port to examine
201 * The capabilities are read from the port's PCI Express configuration registers
202 * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
205 * Return value: Bitmask of discovered port capabilities
207 static int get_port_device_capability(struct pci_dev *dev)
209 struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
212 if (dev->is_hotplug_bridge &&
213 (pcie_ports_native || host->native_pcie_hotplug)) {
214 services |= PCIE_PORT_SERVICE_HP;
217 * Disable hot-plug interrupts in case they have been enabled
218 * by the BIOS and the hot-plug service driver is not loaded.
220 pcie_capability_clear_word(dev, PCI_EXP_SLTCTL,
221 PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
224 #ifdef CONFIG_PCIEAER
225 if (dev->aer_cap && pci_aer_available() &&
226 (pcie_ports_native || host->native_aer)) {
227 services |= PCIE_PORT_SERVICE_AER;
230 * Disable AER on this port in case it's been enabled by the
231 * BIOS (the AER service driver will enable it when necessary).
233 pci_disable_pcie_error_reporting(dev);
238 * Root ports are capable of generating PME too. Root Complex
239 * Event Collectors can also generate PMEs, but we don't handle
242 if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
243 (pcie_ports_native || host->native_pme)) {
244 services |= PCIE_PORT_SERVICE_PME;
247 * Disable PME interrupt on this port in case it's been enabled
248 * by the BIOS (the PME service driver will enable it when
251 pcie_pme_interrupt_enable(dev, false);
254 if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
255 pci_aer_available() && services & PCIE_PORT_SERVICE_AER)
256 services |= PCIE_PORT_SERVICE_DPC;
258 if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
259 pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
260 services |= PCIE_PORT_SERVICE_BWNOTIF;
266 * pcie_device_init - allocate and initialize PCI Express port service device
267 * @pdev: PCI Express port to associate the service device with
268 * @service: Type of service to associate with the service device
269 * @irq: Interrupt vector to associate with the service device
271 static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
274 struct pcie_device *pcie;
275 struct device *device;
277 pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
282 pcie->service = service;
284 /* Initialize generic device interface */
285 device = &pcie->device;
286 device->bus = &pcie_port_bus_type;
287 device->release = release_pcie_device; /* callback to free pcie dev */
288 dev_set_name(device, "%s:pcie%03x",
290 get_descriptor_id(pci_pcie_type(pdev), service));
291 device->parent = &pdev->dev;
292 device_enable_async_suspend(device);
294 retval = device_register(device);
300 pm_runtime_no_callbacks(device);
306 * pcie_port_device_register - register PCI Express port
307 * @dev: PCI Express port to register
309 * Allocate the port extension structure and register services associated with
312 int pcie_port_device_register(struct pci_dev *dev)
314 int status, capabilities, i, nr_service;
315 int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
317 /* Enable PCI Express port device */
318 status = pci_enable_device(dev);
322 /* Get and check PCI Express port services */
323 capabilities = get_port_device_capability(dev);
329 * Initialize service irqs. Don't use service devices that
330 * require interrupts if there is no way to generate them.
331 * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
332 * that can be used in the absence of irqs. Allow them to determine
333 * if that is to be used.
335 status = pcie_init_service_irqs(dev, irqs, capabilities);
337 capabilities &= PCIE_PORT_SERVICE_HP;
342 /* Allocate child services if any */
345 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
346 int service = 1 << i;
347 if (!(capabilities & service))
349 if (!pcie_device_init(dev, service, irqs[i]))
353 goto error_cleanup_irqs;
358 pci_free_irq_vectors(dev);
360 pci_disable_device(dev);
365 typedef int (*pcie_pm_callback_t)(struct pcie_device *);
367 static int pm_iter(struct device *dev, void *data)
369 struct pcie_port_service_driver *service_driver;
370 size_t offset = *(size_t *)data;
371 pcie_pm_callback_t cb;
373 if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
374 service_driver = to_service_driver(dev->driver);
375 cb = *(pcie_pm_callback_t *)((void *)service_driver + offset);
377 return cb(to_pcie_device(dev));
382 static int get_downstream_delay(struct pci_bus *bus)
384 struct pci_dev *pdev;
388 list_for_each_entry(pdev, &bus->devices, bus_list) {
389 if (!pdev->imm_ready)
391 else if (pdev->d3cold_delay < min_delay)
392 min_delay = pdev->d3cold_delay;
393 if (pdev->d3cold_delay > max_delay)
394 max_delay = pdev->d3cold_delay;
397 return max(min_delay, max_delay);
401 * wait_for_downstream_link - Wait for downstream link to establish
402 * @pdev: PCIe port whose downstream link is waited
404 * Handle delays according to PCIe 4.0 section 6.6.1 before configuration
405 * access to the downstream component is permitted.
407 * This blocks PCI core resume of the hierarchy below this port until the
408 * link is trained. Should be called before resuming port services to
409 * prevent pciehp from starting to tear-down the hierarchy too soon.
411 static void wait_for_downstream_link(struct pci_dev *pdev)
415 if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT &&
416 pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
419 if (pci_dev_is_disconnected(pdev))
422 if (!pdev->subordinate || list_empty(&pdev->subordinate->devices) ||
426 delay = get_downstream_delay(pdev->subordinate);
430 dev_dbg(&pdev->dev, "waiting downstream link for %d ms\n", delay);
433 * If downstream port does not support speeds greater than 5 GT/s
434 * need to wait 100ms. For higher speeds (gen3) we need to wait
435 * first for the data link layer to become active.
437 if (pcie_get_speed_cap(pdev) <= PCIE_SPEED_5_0GT)
440 pcie_wait_for_link_delay(pdev, true, delay);
444 * pcie_port_device_suspend - suspend port services associated with a PCIe port
445 * @dev: PCI Express port to handle
447 int pcie_port_device_suspend(struct device *dev)
449 size_t off = offsetof(struct pcie_port_service_driver, suspend);
450 return device_for_each_child(dev, &off, pm_iter);
453 int pcie_port_device_resume_noirq(struct device *dev)
455 size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
457 wait_for_downstream_link(to_pci_dev(dev));
458 return device_for_each_child(dev, &off, pm_iter);
462 * pcie_port_device_resume - resume port services associated with a PCIe port
463 * @dev: PCI Express port to handle
465 int pcie_port_device_resume(struct device *dev)
467 size_t off = offsetof(struct pcie_port_service_driver, resume);
468 return device_for_each_child(dev, &off, pm_iter);
472 * pcie_port_device_runtime_suspend - runtime suspend port services
473 * @dev: PCI Express port to handle
475 int pcie_port_device_runtime_suspend(struct device *dev)
477 size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
478 return device_for_each_child(dev, &off, pm_iter);
482 * pcie_port_device_runtime_resume - runtime resume port services
483 * @dev: PCI Express port to handle
485 int pcie_port_device_runtime_resume(struct device *dev)
487 size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
489 wait_for_downstream_link(to_pci_dev(dev));
490 return device_for_each_child(dev, &off, pm_iter);
494 static int remove_iter(struct device *dev, void *data)
496 if (dev->bus == &pcie_port_bus_type)
497 device_unregister(dev);
501 static int find_service_iter(struct device *device, void *data)
503 struct pcie_port_service_driver *service_driver;
504 struct portdrv_service_data *pdrvs;
507 pdrvs = (struct portdrv_service_data *) data;
508 service = pdrvs->service;
510 if (device->bus == &pcie_port_bus_type && device->driver) {
511 service_driver = to_service_driver(device->driver);
512 if (service_driver->service == service) {
513 pdrvs->drv = service_driver;
523 * pcie_port_find_service - find the service driver
524 * @dev: PCI Express port the service is associated with
525 * @service: Service to find
527 * Find PCI Express port service driver associated with given service
529 struct pcie_port_service_driver *pcie_port_find_service(struct pci_dev *dev,
532 struct pcie_port_service_driver *drv;
533 struct portdrv_service_data pdrvs;
536 pdrvs.service = service;
537 device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
544 * pcie_port_find_device - find the struct device
545 * @dev: PCI Express port the service is associated with
546 * @service: For the service to find
548 * Find the struct device associated with given service on a pci_dev
550 struct device *pcie_port_find_device(struct pci_dev *dev,
553 struct device *device;
554 struct portdrv_service_data pdrvs;
557 pdrvs.service = service;
558 device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
563 EXPORT_SYMBOL_GPL(pcie_port_find_device);
566 * pcie_port_device_remove - unregister PCI Express port service devices
567 * @dev: PCI Express port the service devices to unregister are associated with
569 * Remove PCI Express port service devices associated with given port and
570 * disable MSI-X or MSI for the port.
572 void pcie_port_device_remove(struct pci_dev *dev)
574 device_for_each_child(&dev->dev, NULL, remove_iter);
575 pci_free_irq_vectors(dev);
576 pci_disable_device(dev);
580 * pcie_port_probe_service - probe driver for given PCI Express port service
581 * @dev: PCI Express port service device to probe against
583 * If PCI Express port service driver is registered with
584 * pcie_port_service_register(), this function will be called by the driver core
585 * whenever match is found between the driver and a port service device.
587 static int pcie_port_probe_service(struct device *dev)
589 struct pcie_device *pciedev;
590 struct pcie_port_service_driver *driver;
593 if (!dev || !dev->driver)
596 driver = to_service_driver(dev->driver);
597 if (!driver || !driver->probe)
600 pciedev = to_pcie_device(dev);
601 status = driver->probe(pciedev);
610 * pcie_port_remove_service - detach driver from given PCI Express port service
611 * @dev: PCI Express port service device to handle
613 * If PCI Express port service driver is registered with
614 * pcie_port_service_register(), this function will be called by the driver core
615 * when device_unregister() is called for the port service device associated
618 static int pcie_port_remove_service(struct device *dev)
620 struct pcie_device *pciedev;
621 struct pcie_port_service_driver *driver;
623 if (!dev || !dev->driver)
626 pciedev = to_pcie_device(dev);
627 driver = to_service_driver(dev->driver);
628 if (driver && driver->remove) {
629 driver->remove(pciedev);
636 * pcie_port_shutdown_service - shut down given PCI Express port service
637 * @dev: PCI Express port service device to handle
639 * If PCI Express port service driver is registered with
640 * pcie_port_service_register(), this function will be called by the driver core
641 * when device_shutdown() is called for the port service device associated
644 static void pcie_port_shutdown_service(struct device *dev) {}
647 * pcie_port_service_register - register PCI Express port service driver
648 * @new: PCI Express port service driver to register
650 int pcie_port_service_register(struct pcie_port_service_driver *new)
652 if (pcie_ports_disabled)
655 new->driver.name = new->name;
656 new->driver.bus = &pcie_port_bus_type;
657 new->driver.probe = pcie_port_probe_service;
658 new->driver.remove = pcie_port_remove_service;
659 new->driver.shutdown = pcie_port_shutdown_service;
661 return driver_register(&new->driver);
663 EXPORT_SYMBOL(pcie_port_service_register);
666 * pcie_port_service_unregister - unregister PCI Express port service driver
667 * @drv: PCI Express port service driver to unregister
669 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
671 driver_unregister(&drv->driver);
673 EXPORT_SYMBOL(pcie_port_service_unregister);