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 
22 struct 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  */
release_pcie_device(struct device * dev)35 static 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  */
pcie_message_numbers(struct pci_dev * dev,int mask,u32 * pme,u32 * aer,u32 * dpc)45 static 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  */
pcie_port_enable_irq_vec(struct pci_dev * dev,int * irqs,int mask)101 static 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  */
pcie_init_service_irqs(struct pci_dev * dev,int * irqs,int mask)165 static 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 
184 legacy_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  */
get_port_device_capability(struct pci_dev * dev)206 static 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 #endif
228 
229 	/* Root Ports and Root Complex Event Collectors may generate PMEs */
230 	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
231 	     pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
232 	    (pcie_ports_native || host->native_pme)) {
233 		services |= PCIE_PORT_SERVICE_PME;
234 
235 		/*
236 		 * Disable PME interrupt on this port in case it's been enabled
237 		 * by the BIOS (the PME service driver will enable it when
238 		 * necessary).
239 		 */
240 		pcie_pme_interrupt_enable(dev, false);
241 	}
242 
243 	/*
244 	 * With dpc-native, allow Linux to use DPC even if it doesn't have
245 	 * permission to use AER.
246 	 */
247 	if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC) &&
248 	    pci_aer_available() &&
249 	    (pcie_ports_dpc_native || (services & PCIE_PORT_SERVICE_AER)))
250 		services |= PCIE_PORT_SERVICE_DPC;
251 
252 	if (pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
253 	    pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
254 		u32 linkcap;
255 
256 		pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &linkcap);
257 		if (linkcap & PCI_EXP_LNKCAP_LBNC)
258 			services |= PCIE_PORT_SERVICE_BWNOTIF;
259 	}
260 
261 	return services;
262 }
263 
264 /**
265  * pcie_device_init - allocate and initialize PCI Express port service device
266  * @pdev: PCI Express port to associate the service device with
267  * @service: Type of service to associate with the service device
268  * @irq: Interrupt vector to associate with the service device
269  */
pcie_device_init(struct pci_dev * pdev,int service,int irq)270 static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
271 {
272 	int retval;
273 	struct pcie_device *pcie;
274 	struct device *device;
275 
276 	pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
277 	if (!pcie)
278 		return -ENOMEM;
279 	pcie->port = pdev;
280 	pcie->irq = irq;
281 	pcie->service = service;
282 
283 	/* Initialize generic device interface */
284 	device = &pcie->device;
285 	device->bus = &pcie_port_bus_type;
286 	device->release = release_pcie_device;	/* callback to free pcie dev */
287 	dev_set_name(device, "%s:pcie%03x",
288 		     pci_name(pdev),
289 		     get_descriptor_id(pci_pcie_type(pdev), service));
290 	device->parent = &pdev->dev;
291 	device_enable_async_suspend(device);
292 
293 	retval = device_register(device);
294 	if (retval) {
295 		put_device(device);
296 		return retval;
297 	}
298 
299 	pm_runtime_no_callbacks(device);
300 
301 	return 0;
302 }
303 
304 /**
305  * pcie_port_device_register - register PCI Express port
306  * @dev: PCI Express port to register
307  *
308  * Allocate the port extension structure and register services associated with
309  * the port.
310  */
pcie_port_device_register(struct pci_dev * dev)311 int pcie_port_device_register(struct pci_dev *dev)
312 {
313 	int status, capabilities, i, nr_service;
314 	int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
315 
316 	/* Enable PCI Express port device */
317 	status = pci_enable_device(dev);
318 	if (status)
319 		return status;
320 
321 	/* Get and check PCI Express port services */
322 	capabilities = get_port_device_capability(dev);
323 	if (!capabilities)
324 		return 0;
325 
326 	pci_set_master(dev);
327 	/*
328 	 * Initialize service irqs. Don't use service devices that
329 	 * require interrupts if there is no way to generate them.
330 	 * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
331 	 * that can be used in the absence of irqs.  Allow them to determine
332 	 * if that is to be used.
333 	 */
334 	status = pcie_init_service_irqs(dev, irqs, capabilities);
335 	if (status) {
336 		capabilities &= PCIE_PORT_SERVICE_HP;
337 		if (!capabilities)
338 			goto error_disable;
339 	}
340 
341 	/* Allocate child services if any */
342 	status = -ENODEV;
343 	nr_service = 0;
344 	for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
345 		int service = 1 << i;
346 		if (!(capabilities & service))
347 			continue;
348 		if (!pcie_device_init(dev, service, irqs[i]))
349 			nr_service++;
350 	}
351 	if (!nr_service)
352 		goto error_cleanup_irqs;
353 
354 	return 0;
355 
356 error_cleanup_irqs:
357 	pci_free_irq_vectors(dev);
358 error_disable:
359 	pci_disable_device(dev);
360 	return status;
361 }
362 
363 typedef int (*pcie_callback_t)(struct pcie_device *);
364 
pcie_port_device_iter(struct device * dev,void * data)365 int pcie_port_device_iter(struct device *dev, void *data)
366 {
367 	struct pcie_port_service_driver *service_driver;
368 	size_t offset = *(size_t *)data;
369 	pcie_callback_t cb;
370 
371 	if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
372 		service_driver = to_service_driver(dev->driver);
373 		cb = *(pcie_callback_t *)((void *)service_driver + offset);
374 		if (cb)
375 			return cb(to_pcie_device(dev));
376 	}
377 	return 0;
378 }
379 
380 #ifdef CONFIG_PM
381 /**
382  * pcie_port_device_suspend - suspend port services associated with a PCIe port
383  * @dev: PCI Express port to handle
384  */
pcie_port_device_suspend(struct device * dev)385 int pcie_port_device_suspend(struct device *dev)
386 {
387 	size_t off = offsetof(struct pcie_port_service_driver, suspend);
388 	return device_for_each_child(dev, &off, pcie_port_device_iter);
389 }
390 
pcie_port_device_resume_noirq(struct device * dev)391 int pcie_port_device_resume_noirq(struct device *dev)
392 {
393 	size_t off = offsetof(struct pcie_port_service_driver, resume_noirq);
394 	return device_for_each_child(dev, &off, pcie_port_device_iter);
395 }
396 
397 /**
398  * pcie_port_device_resume - resume port services associated with a PCIe port
399  * @dev: PCI Express port to handle
400  */
pcie_port_device_resume(struct device * dev)401 int pcie_port_device_resume(struct device *dev)
402 {
403 	size_t off = offsetof(struct pcie_port_service_driver, resume);
404 	return device_for_each_child(dev, &off, pcie_port_device_iter);
405 }
406 
407 /**
408  * pcie_port_device_runtime_suspend - runtime suspend port services
409  * @dev: PCI Express port to handle
410  */
pcie_port_device_runtime_suspend(struct device * dev)411 int pcie_port_device_runtime_suspend(struct device *dev)
412 {
413 	size_t off = offsetof(struct pcie_port_service_driver, runtime_suspend);
414 	return device_for_each_child(dev, &off, pcie_port_device_iter);
415 }
416 
417 /**
418  * pcie_port_device_runtime_resume - runtime resume port services
419  * @dev: PCI Express port to handle
420  */
pcie_port_device_runtime_resume(struct device * dev)421 int pcie_port_device_runtime_resume(struct device *dev)
422 {
423 	size_t off = offsetof(struct pcie_port_service_driver, runtime_resume);
424 	return device_for_each_child(dev, &off, pcie_port_device_iter);
425 }
426 #endif /* PM */
427 
remove_iter(struct device * dev,void * data)428 static int remove_iter(struct device *dev, void *data)
429 {
430 	if (dev->bus == &pcie_port_bus_type)
431 		device_unregister(dev);
432 	return 0;
433 }
434 
find_service_iter(struct device * device,void * data)435 static int find_service_iter(struct device *device, void *data)
436 {
437 	struct pcie_port_service_driver *service_driver;
438 	struct portdrv_service_data *pdrvs;
439 	u32 service;
440 
441 	pdrvs = (struct portdrv_service_data *) data;
442 	service = pdrvs->service;
443 
444 	if (device->bus == &pcie_port_bus_type && device->driver) {
445 		service_driver = to_service_driver(device->driver);
446 		if (service_driver->service == service) {
447 			pdrvs->drv = service_driver;
448 			pdrvs->dev = device;
449 			return 1;
450 		}
451 	}
452 
453 	return 0;
454 }
455 
456 /**
457  * pcie_port_find_device - find the struct device
458  * @dev: PCI Express port the service is associated with
459  * @service: For the service to find
460  *
461  * Find the struct device associated with given service on a pci_dev
462  */
pcie_port_find_device(struct pci_dev * dev,u32 service)463 struct device *pcie_port_find_device(struct pci_dev *dev,
464 				      u32 service)
465 {
466 	struct device *device;
467 	struct portdrv_service_data pdrvs;
468 
469 	pdrvs.dev = NULL;
470 	pdrvs.service = service;
471 	device_for_each_child(&dev->dev, &pdrvs, find_service_iter);
472 
473 	device = pdrvs.dev;
474 	return device;
475 }
476 EXPORT_SYMBOL_GPL(pcie_port_find_device);
477 
478 /**
479  * pcie_port_device_remove - unregister PCI Express port service devices
480  * @dev: PCI Express port the service devices to unregister are associated with
481  *
482  * Remove PCI Express port service devices associated with given port and
483  * disable MSI-X or MSI for the port.
484  */
pcie_port_device_remove(struct pci_dev * dev)485 void pcie_port_device_remove(struct pci_dev *dev)
486 {
487 	device_for_each_child(&dev->dev, NULL, remove_iter);
488 	pci_free_irq_vectors(dev);
489 	pci_disable_device(dev);
490 }
491 
492 /**
493  * pcie_port_probe_service - probe driver for given PCI Express port service
494  * @dev: PCI Express port service device to probe against
495  *
496  * If PCI Express port service driver is registered with
497  * pcie_port_service_register(), this function will be called by the driver core
498  * whenever match is found between the driver and a port service device.
499  */
pcie_port_probe_service(struct device * dev)500 static int pcie_port_probe_service(struct device *dev)
501 {
502 	struct pcie_device *pciedev;
503 	struct pcie_port_service_driver *driver;
504 	int status;
505 
506 	if (!dev || !dev->driver)
507 		return -ENODEV;
508 
509 	driver = to_service_driver(dev->driver);
510 	if (!driver || !driver->probe)
511 		return -ENODEV;
512 
513 	pciedev = to_pcie_device(dev);
514 	status = driver->probe(pciedev);
515 	if (status)
516 		return status;
517 
518 	get_device(dev);
519 	return 0;
520 }
521 
522 /**
523  * pcie_port_remove_service - detach driver from 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_unregister() is called for the port service device associated
529  * with the driver.
530  */
pcie_port_remove_service(struct device * dev)531 static int pcie_port_remove_service(struct device *dev)
532 {
533 	struct pcie_device *pciedev;
534 	struct pcie_port_service_driver *driver;
535 
536 	if (!dev || !dev->driver)
537 		return 0;
538 
539 	pciedev = to_pcie_device(dev);
540 	driver = to_service_driver(dev->driver);
541 	if (driver && driver->remove) {
542 		driver->remove(pciedev);
543 		put_device(dev);
544 	}
545 	return 0;
546 }
547 
548 /**
549  * pcie_port_shutdown_service - shut down given PCI Express port service
550  * @dev: PCI Express port service device to handle
551  *
552  * If PCI Express port service driver is registered with
553  * pcie_port_service_register(), this function will be called by the driver core
554  * when device_shutdown() is called for the port service device associated
555  * with the driver.
556  */
pcie_port_shutdown_service(struct device * dev)557 static void pcie_port_shutdown_service(struct device *dev) {}
558 
559 /**
560  * pcie_port_service_register - register PCI Express port service driver
561  * @new: PCI Express port service driver to register
562  */
pcie_port_service_register(struct pcie_port_service_driver * new)563 int pcie_port_service_register(struct pcie_port_service_driver *new)
564 {
565 	if (pcie_ports_disabled)
566 		return -ENODEV;
567 
568 	new->driver.name = new->name;
569 	new->driver.bus = &pcie_port_bus_type;
570 	new->driver.probe = pcie_port_probe_service;
571 	new->driver.remove = pcie_port_remove_service;
572 	new->driver.shutdown = pcie_port_shutdown_service;
573 
574 	return driver_register(&new->driver);
575 }
576 EXPORT_SYMBOL(pcie_port_service_register);
577 
578 /**
579  * pcie_port_service_unregister - unregister PCI Express port service driver
580  * @drv: PCI Express port service driver to unregister
581  */
pcie_port_service_unregister(struct pcie_port_service_driver * drv)582 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
583 {
584 	driver_unregister(&drv->driver);
585 }
586 EXPORT_SYMBOL(pcie_port_service_unregister);
587