1// SPDX-License-Identifier: GPL-2.0
  2/*
  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/pm_runtime.h>
 15#include <linux/string.h>
 16#include <linux/slab.h>
 17#include <linux/aer.h>
 18
 19#include "../pci.h"
 20#include "portdrv.h"
 21
 22struct portdrv_service_data {
 23	struct pcie_port_service_driver *drv;
 24	struct device *dev;
 25	u32 service;
 26};
 27
 28/**
 29 * release_pcie_device - free PCI Express port service device structure
 30 * @dev: Port service device to release
 31 *
 32 * Invoked automatically when device is being removed in response to
 33 * device_unregister(dev).  Release all resources being claimed.
 34 */
 35static void release_pcie_device(struct device *dev)
 36{
 37	kfree(to_pcie_device(dev));
 38}
 39
 40/*
 41 * Fill in *pme, *aer, *dpc with the relevant Interrupt Message Numbers if
 42 * services are enabled in "mask".  Return the number of MSI/MSI-X vectors
 43 * required to accommodate the largest Message Number.
 44 */
 45static int pcie_message_numbers(struct pci_dev *dev, int mask,
 46				u32 *pme, u32 *aer, u32 *dpc)
 47{
 48	u32 nvec = 0, pos;
 49	u16 reg16;
 50
 51	/*
 52	 * The Interrupt Message Number indicates which vector is used, i.e.,
 53	 * the MSI-X table entry or the MSI offset between the base Message
 54	 * Data and the generated interrupt message.  See PCIe r3.1, sec
 55	 * 7.8.2, 7.10.10, 7.31.2.
 56	 */
 57
 58	if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
 59		    PCIE_PORT_SERVICE_BWNOTIF)) {
 60		pcie_capability_read_word(dev, PCI_EXP_FLAGS, &reg16);
 61		*pme = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
 62		nvec = *pme + 1;
 63	}
 64
 65#ifdef CONFIG_PCIEAER
 66	if (mask & PCIE_PORT_SERVICE_AER) {
 67		u32 reg32;
 68
 69		pos = dev->aer_cap;
 70		if (pos) {
 71			pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS,
 72					      &reg32);
 73			*aer = (reg32 & PCI_ERR_ROOT_AER_IRQ) >> 27;
 74			nvec = max(nvec, *aer + 1);
 75		}
 76	}
 77#endif
 78
 79	if (mask & PCIE_PORT_SERVICE_DPC) {
 80		pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
 81		if (pos) {
 82			pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP,
 83					     &reg16);
 84			*dpc = reg16 & PCI_EXP_DPC_IRQ;
 85			nvec = max(nvec, *dpc + 1);
 86		}
 87	}
 88
 89	return nvec;
 90}
 91
 92/**
 93 * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
 94 * for given port
 95 * @dev: PCI Express port to handle
 96 * @irqs: Array of interrupt vectors to populate
 97 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
 98 *
 99 * Return value: 0 on success, error code on failure
100 */
101static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
102{
103	int nr_entries, nvec, pcie_irq;
104	u32 pme = 0, aer = 0, dpc = 0;
105
106	/* Allocate the maximum possible number of MSI/MSI-X vectors */
107	nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
108			PCI_IRQ_MSIX | PCI_IRQ_MSI);
109	if (nr_entries < 0)
110		return nr_entries;
111
112	/* See how many and which Interrupt Message Numbers we actually use */
113	nvec = pcie_message_numbers(dev, mask, &pme, &aer, &dpc);
114	if (nvec > nr_entries) {
115		pci_free_irq_vectors(dev);
116		return -EIO;
117	}
118
119	/*
120	 * If we allocated more than we need, free them and reallocate fewer.
121	 *
122	 * Reallocating may change the specific vectors we get, so
123	 * pci_irq_vector() must be done *after* the reallocation.
124	 *
125	 * If we're using MSI, hardware is *allowed* to change the Interrupt
126	 * Message Numbers when we free and reallocate the vectors, but we
127	 * assume it won't because we allocate enough vectors for the
128	 * biggest Message Number we found.
129	 */
130	if (nvec != nr_entries) {
131		pci_free_irq_vectors(dev);
132
133		nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
134				PCI_IRQ_MSIX | PCI_IRQ_MSI);
135		if (nr_entries < 0)
136			return nr_entries;
137	}
138
139	/* PME, hotplug and bandwidth notification share an MSI/MSI-X vector */
140	if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP |
141		    PCIE_PORT_SERVICE_BWNOTIF)) {
142		pcie_irq = pci_irq_vector(dev, pme);
143		irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pcie_irq;
144		irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pcie_irq;
145		irqs[PCIE_PORT_SERVICE_BWNOTIF_SHIFT] = pcie_irq;
146	}
147
148	if (mask & PCIE_PORT_SERVICE_AER)
149		irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, aer);
150
151	if (mask & PCIE_PORT_SERVICE_DPC)
152		irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, dpc);
153
154	return 0;
155}
156
157/**
158 * pcie_init_service_irqs - initialize irqs for PCI Express port services
159 * @dev: PCI Express port to handle
160 * @irqs: Array of irqs to populate
161 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
162 *
163 * Return value: Interrupt mode associated with the port
164 */
165static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
166{
167	int ret, i;
168
169	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
170		irqs[i] = -1;
171
172	/*
173	 * If we support PME but can't use MSI/MSI-X for it, we have to
174	 * fall back to INTx or other interrupts, e.g., a system shared
175	 * interrupt.
176	 */
177	if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
178		goto legacy_irq;
179
180	/* Try to use MSI-X or MSI if supported */
181	if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
182		return 0;
183
184legacy_irq:
185	/* fall back to legacy IRQ */
186	ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
187	if (ret < 0)
188		return -ENODEV;
189
190	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
191		irqs[i] = pci_irq_vector(dev, 0);
192
193	return 0;
194}
195
196/**
197 * get_port_device_capability - discover capabilities of a PCI Express port
198 * @dev: PCI Express port to examine
199 *
200 * The capabilities are read from the port's PCI Express configuration registers
201 * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
202 * 7.9 - 7.11.
203 *
204 * Return value: Bitmask of discovered port capabilities
205 */
206static int get_port_device_capability(struct pci_dev *dev)
207{
208	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
209	int services = 0;
210
211	if (dev->is_hotplug_bridge &&
212	    (pcie_ports_native || host->native_pcie_hotplug)) {
213		services |= PCIE_PORT_SERVICE_HP;
214
215		/*
216		 * Disable hot-plug interrupts in case they have been enabled
217		 * by the BIOS and the hot-plug service driver is not loaded.
218		 */
219		pcie_capability_clear_word(dev, PCI_EXP_SLTCTL,
220			  PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
221	}
222
223#ifdef CONFIG_PCIEAER
224	if (dev->aer_cap && pci_aer_available() &&
225	    (pcie_ports_native || host->native_aer)) {
226		services |= PCIE_PORT_SERVICE_AER;
227
228		/*
229		 * Disable AER on this port in case it's been enabled by the
230		 * BIOS (the AER service driver will enable it when necessary).
231		 */
232		pci_disable_pcie_error_reporting(dev);
233	}
234#endif
235
236	/* Root Ports and Root Complex Event Collectors may generate PMEs */
237	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
238	     pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
239	    (pcie_ports_native || host->native_pme)) {
240		services |= PCIE_PORT_SERVICE_PME;
241
242		/*
243		 * Disable PME interrupt on this port in case it's been enabled
244		 * by the BIOS (the PME service driver will enable it when
245		 * necessary).
246		 */
247		pcie_pme_interrupt_enable(dev, false);
248	}
249
250	/*
251	 * With dpc-native, allow Linux to use DPC even if it doesn't have
252	 * permission to use AER.
253	 */
254	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
255	    pci_aer_available() &&
256	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
257		services |= PCIE_PORT_SERVICE_DPC;
258
259	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
260	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
261		u32 linkcap;
262
263		pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
264		if (linkcap & PCI_EXP_LNKCAP_LBNC)
265			services |= PCIE_PORT_SERVICE_BWNOTIF;
266	}
267
268	return services;
269}
270
271/**
272 * pcie_device_init - allocate and initialize PCI Express port service device
273 * @pdev: PCI Express port to associate the service device with
274 * @service: Type of service to associate with the service device
275 * @irq: Interrupt vector to associate with the service device
276 */
277static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
278{
279	int retval;
280	struct pcie_device *pcie;
281	struct device *device;
282
283	pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
284	if (!pcie)
285		return -ENOMEM;
286	pcie->port = pdev;
287	pcie->irq = irq;
288	pcie->service = service;
289
290	/* Initialize generic device interface */
291	device = &pcie->device;
292	device->bus = &pcie_port_bus_type;
293	device->release = release_pcie_device;	/* callback to free pcie dev */
294	dev_set_name(device, "%s:pcie%03x",
295		     pci_name(pdev),
296		     get_descriptor_id(pci_pcie_type(pdev), service));
297	device->parent = &pdev->dev;
298	device_enable_async_suspend(device);
299
300	retval = device_register(device);
301	if (retval) {
302		put_device(device);
303		return retval;
304	}
305
306	pm_runtime_no_callbacks(device);
307
308	return 0;
309}
310
311/**
312 * pcie_port_device_register - register PCI Express port
313 * @dev: PCI Express port to register
314 *
315 * Allocate the port extension structure and register services associated with
316 * the port.
317 */
318int pcie_port_device_register(struct pci_dev *dev)
319{
320	int status, capabilities, i, nr_service;
321	int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
322
323	/* Enable PCI Express port device */
324	status = pci_enable_device(dev);
325	if (status)
326		return status;
327
328	/* Get and check PCI Express port services */
329	capabilities = get_port_device_capability(dev);
330	if (!capabilities)
331		return 0;
332
333	pci_set_master(dev);
334	/*
335	 * Initialize service irqs. Don't use service devices that
336	 * require interrupts if there is no way to generate them.
337	 * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
338	 * that can be used in the absence of irqs.  Allow them to determine
339	 * if that is to be used.
340	 */
341	status = pcie_init_service_irqs(dev, irqs, capabilities);
342	if (status) {
343		capabilities &= PCIE_PORT_SERVICE_HP;
344		if (!capabilities)
345			goto error_disable;
346	}
347
348	/* Allocate child services if any */
349	status = -ENODEV;
350	nr_service = 0;
351	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
352		int service = 1 << i;
353		if (!(capabilities & service))
354			continue;
355		if (!pcie_device_init(dev, service, irqs[i]))
356			nr_service++;
357	}
358	if (!nr_service)
359		goto error_cleanup_irqs;
360
361	return 0;
362
363error_cleanup_irqs:
364	pci_free_irq_vectors(dev);
365error_disable:
366	pci_disable_device(dev);
367	return status;
368}
369
370#ifdef CONFIG_PM
371typedef int (*pcie_pm_callback_t)(struct pcie_device *);
372
373static int pm_iter(struct device *dev, void *data)
374{
375	struct pcie_port_service_driver *service_driver;
376	size_t offset = *(size_t *)data;
377	pcie_pm_callback_t cb;
378
379	if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
380		service_driver = to_service_driver(dev->driver);
381		cb = *(pcie_pm_callback_t *)((void *)service_driver + offset);
382		if (cb)
383			return cb(to_pcie_device(dev));
384	}
385	return 0;
386}
387
388/**
389 * pcie_port_device_suspend - suspend port services associated with a PCIe port
390 * @dev: PCI Express port to handle
391 */
392int pcie_port_device_suspend(struct device *dev)
393{
394	size_t off = offsetof(struct pcie_port_service_driver, suspend);
395	return device_for_each_child(dev, &off, pm_iter);
396}
397
398int pcie_port_device_resume_noirq(struct device *dev)
399{
400	size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
401	return device_for_each_child(dev, &off, pm_iter);
402}
403
404/**
405 * pcie_port_device_resume - resume port services associated with a PCIe port
406 * @dev: PCI Express port to handle
407 */
408int pcie_port_device_resume(struct device *dev)
409{
410	size_t off = offsetof(struct pcie_port_service_driver, resume);
411	return device_for_each_child(dev, &off, pm_iter);
412}
413
414/**
415 * pcie_port_device_runtime_suspend - runtime suspend port services
416 * @dev: PCI Express port to handle
417 */
418int pcie_port_device_runtime_suspend(struct device *dev)
419{
420	size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
421	return device_for_each_child(dev, &off, pm_iter);
422}
423
424/**
425 * pcie_port_device_runtime_resume - runtime resume port services
426 * @dev: PCI Express port to handle
427 */
428int pcie_port_device_runtime_resume(struct device *dev)
429{
430	size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
431	return device_for_each_child(dev, &off, pm_iter);
432}
433#endif /* PM */
434
435static int remove_iter(struct device *dev, void *data)
436{
437	if (dev->bus == &pcie_port_bus_type)
438		device_unregister(dev);
439	return 0;
440}
441
442static int find_service_iter(struct device *device, void *data)
443{
444	struct pcie_port_service_driver *service_driver;
445	struct portdrv_service_data *pdrvs;
446	u32 service;
447
448	pdrvs = (struct portdrv_service_data *) data;
449	service = pdrvs->service;
450
451	if (device->bus == &pcie_port_bus_type && device->driver) {
452		service_driver = to_service_driver(device->driver);
453		if (service_driver->service == service) {
454			pdrvs->drv = service_driver;
455			pdrvs->dev = device;
456			return 1;
457		}
458	}
459
460	return 0;
461}
462
463/**
464 * pcie_port_find_device - find the struct device
465 * @dev: PCI Express port the service is associated with
466 * @service: For the service to find
467 *
468 * Find the struct device associated with given service on a pci_dev
469 */
470struct device *pcie_port_find_device(struct pci_dev *dev,
471				      u32 service)
472{
473	struct device *device;
474	struct portdrv_service_data pdrvs;
475
476	pdrvs.dev = NULL;
477	pdrvs.service = service;
478	device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
479
480	device = pdrvs.dev;
481	return device;
482}
483EXPORT_SYMBOL_GPL(pcie_port_find_device);
484
485/**
486 * pcie_port_device_remove - unregister PCI Express port service devices
487 * @dev: PCI Express port the service devices to unregister are associated with
488 *
489 * Remove PCI Express port service devices associated with given port and
490 * disable MSI-X or MSI for the port.
491 */
492void pcie_port_device_remove(struct pci_dev *dev)
493{
494	device_for_each_child(&dev->dev, NULL, remove_iter);
495	pci_free_irq_vectors(dev);
496	pci_disable_device(dev);
497}
498
499/**
500 * pcie_port_probe_service - probe driver for given PCI Express port service
501 * @dev: PCI Express port service device to probe against
502 *
503 * If PCI Express port service driver is registered with
504 * pcie_port_service_register(), this function will be called by the driver core
505 * whenever match is found between the driver and a port service device.
506 */
507static int pcie_port_probe_service(struct device *dev)
508{
509	struct pcie_device *pciedev;
510	struct pcie_port_service_driver *driver;
511	int status;
512
513	if (!dev || !dev->driver)
514		return -ENODEV;
515
516	driver = to_service_driver(dev->driver);
517	if (!driver || !driver->probe)
518		return -ENODEV;
519
520	pciedev = to_pcie_device(dev);
521	status = driver->probe(pciedev);
522	if (status)
523		return status;
524
525	get_device(dev);
526	return 0;
527}
528
529/**
530 * pcie_port_remove_service - detach driver from given PCI Express port service
531 * @dev: PCI Express port service device to handle
532 *
533 * If PCI Express port service driver is registered with
534 * pcie_port_service_register(), this function will be called by the driver core
535 * when device_unregister() is called for the port service device associated
536 * with the driver.
537 */
538static int pcie_port_remove_service(struct device *dev)
539{
540	struct pcie_device *pciedev;
541	struct pcie_port_service_driver *driver;
542
543	if (!dev || !dev->driver)
544		return 0;
545
546	pciedev = to_pcie_device(dev);
547	driver = to_service_driver(dev->driver);
548	if (driver && driver->remove) {
549		driver->remove(pciedev);
550		put_device(dev);
551	}
552	return 0;
553}
554
555/**
556 * pcie_port_shutdown_service - shut down given PCI Express port service
557 * @dev: PCI Express port service device to handle
558 *
559 * If PCI Express port service driver is registered with
560 * pcie_port_service_register(), this function will be called by the driver core
561 * when device_shutdown() is called for the port service device associated
562 * with the driver.
563 */
564static void pcie_port_shutdown_service(struct device *dev) {}
565
566/**
567 * pcie_port_service_register - register PCI Express port service driver
568 * @new: PCI Express port service driver to register
569 */
570int pcie_port_service_register(struct pcie_port_service_driver *new)
571{
572	if (pcie_ports_disabled)
573		return -ENODEV;
574
575	new->driver.name = new->name;
576	new->driver.bus = &pcie_port_bus_type;
577	new->driver.probe = pcie_port_probe_service;
578	new->driver.remove = pcie_port_remove_service;
579	new->driver.shutdown = pcie_port_shutdown_service;
580
581	return driver_register(&new->driver);
582}
583EXPORT_SYMBOL(pcie_port_service_register);
584
585/**
586 * pcie_port_service_unregister - unregister PCI Express port service driver
587 * @drv: PCI Express port service driver to unregister
588 */
589void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
590{
591	driver_unregister(&drv->driver);
592}
593EXPORT_SYMBOL(pcie_port_service_unregister);