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	/*
237	 * Root ports are capable of generating PME too.  Root Complex
238	 * Event Collectors can also generate PMEs, but we don't handle
239	 * those yet.
240	 */
241	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
242	    (pcie_ports_native || host->native_pme)) {
243		services |= PCIE_PORT_SERVICE_PME;
244
245		/*
246		 * Disable PME interrupt on this port in case it's been enabled
247		 * by the BIOS (the PME service driver will enable it when
248		 * necessary).
249		 */
250		pcie_pme_interrupt_enable(dev, false);
251	}
252
253	/*
254	 * With dpc-native, allow Linux to use DPC even if it doesn't have
255	 * permission to use AER.
256	 */
257	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
258	    pci_aer_available() &&
259	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
260		services |= PCIE_PORT_SERVICE_DPC;
261
262	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
263	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT)
264		services |= PCIE_PORT_SERVICE_BWNOTIF;
265
266	return services;
267}
268
269/**
270 * pcie_device_init - allocate and initialize PCI Express port service device
271 * @pdev: PCI Express port to associate the service device with
272 * @service: Type of service to associate with the service device
273 * @irq: Interrupt vector to associate with the service device
274 */
275static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
276{
277	int retval;
278	struct pcie_device *pcie;
279	struct device *device;
280
281	pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
282	if (!pcie)
283		return -ENOMEM;
284	pcie->port = pdev;
285	pcie->irq = irq;
286	pcie->service = service;
287
288	/* Initialize generic device interface */
289	device = &pcie->device;
290	device->bus = &pcie_port_bus_type;
291	device->release = release_pcie_device;	/* callback to free pcie dev */
292	dev_set_name(device, "%s:pcie%03x",
293		     pci_name(pdev),
294		     get_descriptor_id(pci_pcie_type(pdev), service));
295	device->parent = &pdev->dev;
296	device_enable_async_suspend(device);
297
298	retval = device_register(device);
299	if (retval) {
300		put_device(device);
301		return retval;
302	}
303
304	pm_runtime_no_callbacks(device);
305
306	return 0;
307}
308
309/**
310 * pcie_port_device_register - register PCI Express port
311 * @dev: PCI Express port to register
312 *
313 * Allocate the port extension structure and register services associated with
314 * the port.
315 */
316int pcie_port_device_register(struct pci_dev *dev)
317{
318	int status, capabilities, i, nr_service;
319	int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
320
321	/* Enable PCI Express port device */
322	status = pci_enable_device(dev);
323	if (status)
324		return status;
325
326	/* Get and check PCI Express port services */
327	capabilities = get_port_device_capability(dev);
328	if (!capabilities)
329		return 0;
330
331	pci_set_master(dev);
332	/*
333	 * Initialize service irqs. Don't use service devices that
334	 * require interrupts if there is no way to generate them.
335	 * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
336	 * that can be used in the absence of irqs.  Allow them to determine
337	 * if that is to be used.
338	 */
339	status = pcie_init_service_irqs(dev, irqs, capabilities);
340	if (status) {
341		capabilities &= PCIE_PORT_SERVICE_HP;
342		if (!capabilities)
343			goto error_disable;
344	}
345
346	/* Allocate child services if any */
347	status = -ENODEV;
348	nr_service = 0;
349	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
350		int service = 1 << i;
351		if (!(capabilities & service))
352			continue;
353		if (!pcie_device_init(dev, service, irqs[i]))
354			nr_service++;
355	}
356	if (!nr_service)
357		goto error_cleanup_irqs;
358
359	return 0;
360
361error_cleanup_irqs:
362	pci_free_irq_vectors(dev);
363error_disable:
364	pci_disable_device(dev);
365	return status;
366}
367
368#ifdef CONFIG_PM
369typedef int (*pcie_pm_callback_t)(struct pcie_device *);
370
371static int pm_iter(struct device *dev, void *data)
372{
373	struct pcie_port_service_driver *service_driver;
374	size_t offset = *(size_t *)data;
375	pcie_pm_callback_t cb;
376
377	if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
378		service_driver = to_service_driver(dev->driver);
379		cb = *(pcie_pm_callback_t *)((void *)service_driver + offset);
380		if (cb)
381			return cb(to_pcie_device(dev));
382	}
383	return 0;
384}
385
386/**
387 * pcie_port_device_suspend - suspend port services associated with a PCIe port
388 * @dev: PCI Express port to handle
389 */
390int pcie_port_device_suspend(struct device *dev)
391{
392	size_t off = offsetof(struct pcie_port_service_driver, suspend);
393	return device_for_each_child(dev, &off, pm_iter);
394}
395
396int pcie_port_device_resume_noirq(struct device *dev)
397{
398	size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
399	return device_for_each_child(dev, &off, pm_iter);
400}
401
402/**
403 * pcie_port_device_resume - resume port services associated with a PCIe port
404 * @dev: PCI Express port to handle
405 */
406int pcie_port_device_resume(struct device *dev)
407{
408	size_t off = offsetof(struct pcie_port_service_driver, resume);
409	return device_for_each_child(dev, &off, pm_iter);
410}
411
412/**
413 * pcie_port_device_runtime_suspend - runtime suspend port services
414 * @dev: PCI Express port to handle
415 */
416int pcie_port_device_runtime_suspend(struct device *dev)
417{
418	size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
419	return device_for_each_child(dev, &off, pm_iter);
420}
421
422/**
423 * pcie_port_device_runtime_resume - runtime resume port services
424 * @dev: PCI Express port to handle
425 */
426int pcie_port_device_runtime_resume(struct device *dev)
427{
428	size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
429	return device_for_each_child(dev, &off, pm_iter);
430}
431#endif /* PM */
432
433static int remove_iter(struct device *dev, void *data)
434{
435	if (dev->bus == &pcie_port_bus_type)
436		device_unregister(dev);
437	return 0;
438}
439
440static int find_service_iter(struct device *device, void *data)
441{
442	struct pcie_port_service_driver *service_driver;
443	struct portdrv_service_data *pdrvs;
444	u32 service;
445
446	pdrvs = (struct portdrv_service_data *) data;
447	service = pdrvs->service;
448
449	if (device->bus == &pcie_port_bus_type && device->driver) {
450		service_driver = to_service_driver(device->driver);
451		if (service_driver->service == service) {
452			pdrvs->drv = service_driver;
453			pdrvs->dev = device;
454			return 1;
455		}
456	}
457
458	return 0;
459}
460
461/**
462 * pcie_port_find_device - find the struct device
463 * @dev: PCI Express port the service is associated with
464 * @service: For the service to find
465 *
466 * Find the struct device associated with given service on a pci_dev
467 */
468struct device *pcie_port_find_device(struct pci_dev *dev,
469				      u32 service)
470{
471	struct device *device;
472	struct portdrv_service_data pdrvs;
473
474	pdrvs.dev = NULL;
475	pdrvs.service = service;
476	device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
477
478	device = pdrvs.dev;
479	return device;
480}
481EXPORT_SYMBOL_GPL(pcie_port_find_device);
482
483/**
484 * pcie_port_device_remove - unregister PCI Express port service devices
485 * @dev: PCI Express port the service devices to unregister are associated with
486 *
487 * Remove PCI Express port service devices associated with given port and
488 * disable MSI-X or MSI for the port.
489 */
490void pcie_port_device_remove(struct pci_dev *dev)
491{
492	device_for_each_child(&dev->dev, NULL, remove_iter);
493	pci_free_irq_vectors(dev);
494	pci_disable_device(dev);
495}
496
497/**
498 * pcie_port_probe_service - probe driver for given PCI Express port service
499 * @dev: PCI Express port service device to probe against
500 *
501 * If PCI Express port service driver is registered with
502 * pcie_port_service_register(), this function will be called by the driver core
503 * whenever match is found between the driver and a port service device.
504 */
505static int pcie_port_probe_service(struct device *dev)
506{
507	struct pcie_device *pciedev;
508	struct pcie_port_service_driver *driver;
509	int status;
510
511	if (!dev || !dev->driver)
512		return -ENODEV;
513
514	driver = to_service_driver(dev->driver);
515	if (!driver || !driver->probe)
516		return -ENODEV;
517
518	pciedev = to_pcie_device(dev);
519	status = driver->probe(pciedev);
520	if (status)
521		return status;
522
523	get_device(dev);
524	return 0;
525}
526
527/**
528 * pcie_port_remove_service - detach driver from given PCI Express port service
529 * @dev: PCI Express port service device to handle
530 *
531 * If PCI Express port service driver is registered with
532 * pcie_port_service_register(), this function will be called by the driver core
533 * when device_unregister() is called for the port service device associated
534 * with the driver.
535 */
536static int pcie_port_remove_service(struct device *dev)
537{
538	struct pcie_device *pciedev;
539	struct pcie_port_service_driver *driver;
540
541	if (!dev || !dev->driver)
542		return 0;
543
544	pciedev = to_pcie_device(dev);
545	driver = to_service_driver(dev->driver);
546	if (driver && driver->remove) {
547		driver->remove(pciedev);
548		put_device(dev);
549	}
550	return 0;
551}
552
553/**
554 * pcie_port_shutdown_service - shut down given PCI Express port service
555 * @dev: PCI Express port service device to handle
556 *
557 * If PCI Express port service driver is registered with
558 * pcie_port_service_register(), this function will be called by the driver core
559 * when device_shutdown() is called for the port service device associated
560 * with the driver.
561 */
562static void pcie_port_shutdown_service(struct device *dev) {}
563
564/**
565 * pcie_port_service_register - register PCI Express port service driver
566 * @new: PCI Express port service driver to register
567 */
568int pcie_port_service_register(struct pcie_port_service_driver *new)
569{
570	if (pcie_ports_disabled)
571		return -ENODEV;
572
573	new->driver.name = new->name;
574	new->driver.bus = &pcie_port_bus_type;
575	new->driver.probe = pcie_port_probe_service;
576	new->driver.remove = pcie_port_remove_service;
577	new->driver.shutdown = pcie_port_shutdown_service;
578
579	return driver_register(&new->driver);
580}
581EXPORT_SYMBOL(pcie_port_service_register);
582
583/**
584 * pcie_port_service_unregister - unregister PCI Express port service driver
585 * @drv: PCI Express port service driver to unregister
586 */
587void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
588{
589	driver_unregister(&drv->driver);
590}
591EXPORT_SYMBOL(pcie_port_service_unregister);