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, ®16);
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 ®32);
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 ®16);
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
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 */
pcie_device_init(struct pci_dev * pdev,int service,int irq)277 static 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 */
pcie_port_device_register(struct pci_dev * dev)318 int 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
363 error_cleanup_irqs:
364 pci_free_irq_vectors(dev);
365 error_disable:
366 pci_disable_device(dev);
367 return status;
368 }
369
370 typedef int (*pcie_callback_t)(struct pcie_device *);
371
pcie_port_device_iter(struct device * dev,void * data)372 int pcie_port_device_iter(struct device *dev, void *data)
373 {
374 struct pcie_port_service_driver *service_driver;
375 size_t offset = *(size_t *)data;
376 pcie_callback_t cb;
377
378 if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
379 service_driver = to_service_driver(dev->driver);
380 cb = *(pcie_callback_t *)((void *)service_driver + offset);
381 if (cb)
382 return cb(to_pcie_device(dev));
383 }
384 return 0;
385 }
386
387 #ifdef CONFIG_PM
388 /**
389 * pcie_port_device_suspend - suspend port services associated with a PCIe port
390 * @dev: PCI Express port to handle
391 */
pcie_port_device_suspend(struct device * dev)392 int 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, pcie_port_device_iter);
396 }
397
pcie_port_device_resume_noirq(struct device * dev)398 int 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, pcie_port_device_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 */
pcie_port_device_resume(struct device * dev)408 int 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, pcie_port_device_iter);
412 }
413
414 /**
415 * pcie_port_device_runtime_suspend - runtime suspend port services
416 * @dev: PCI Express port to handle
417 */
pcie_port_device_runtime_suspend(struct device * dev)418 int 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, pcie_port_device_iter);
422 }
423
424 /**
425 * pcie_port_device_runtime_resume - runtime resume port services
426 * @dev: PCI Express port to handle
427 */
pcie_port_device_runtime_resume(struct device * dev)428 int 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, pcie_port_device_iter);
432 }
433 #endif /* PM */
434
remove_iter(struct device * dev,void * data)435 static 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
find_service_iter(struct device * device,void * data)442 static 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 */
pcie_port_find_device(struct pci_dev * dev,u32 service)470 struct 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 }
483 EXPORT_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 */
pcie_port_device_remove(struct pci_dev * dev)492 void 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 */
pcie_port_probe_service(struct device * dev)507 static 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 */
pcie_port_remove_service(struct device * dev)538 static 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 */
pcie_port_shutdown_service(struct device * dev)564 static 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 */
pcie_port_service_register(struct pcie_port_service_driver * new)570 int 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 }
583 EXPORT_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 */
pcie_port_service_unregister(struct pcie_port_service_driver * drv)589 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
590 {
591 driver_unregister(&drv->driver);
592 }
593 EXPORT_SYMBOL(pcie_port_service_unregister);
594