1 // SPDX-License-Identifier: GPL-2.0
4 * Purpose: PCI Express Port Bus Driver's Core Functions
6 * Copyright (C) 2004 Intel
7 * Copyright (C) Tom Long Nguyen (tom.l.nguyen@intel.com)
10 #include <linux/module.h>
11 #include <linux/pci.h>
12 #include <linux/kernel.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/pcieport_if.h>
19 #include <linux/aer.h>
24 bool pciehp_msi_disabled;
26 static int __init pciehp_setup(char *str)
28 if (!strncmp(str, "nomsi", 5))
29 pciehp_msi_disabled = true;
33 __setup("pcie_hp=", pciehp_setup);
36 * release_pcie_device - free PCI Express port service device structure
37 * @dev: Port service device to release
39 * Invoked automatically when device is being removed in response to
40 * device_unregister(dev). Release all resources being claimed.
42 static void release_pcie_device(struct device *dev)
44 kfree(to_pcie_device(dev));
48 * pcie_port_enable_irq_vec - try to set up MSI-X or MSI as interrupt mode
50 * @dev: PCI Express port to handle
51 * @irqs: Array of interrupt vectors to populate
52 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
54 * Return value: 0 on success, error code on failure
56 static int pcie_port_enable_irq_vec(struct pci_dev *dev, int *irqs, int mask)
58 int nr_entries, entry, nvec = 0;
61 * Allocate as many entries as the port wants, so that we can check
62 * which of them will be useful. Moreover, if nr_entries is correctly
63 * equal to the number of entries this port actually uses, we'll happily
64 * go through without any tricks.
66 nr_entries = pci_alloc_irq_vectors(dev, 1, PCIE_PORT_MAX_MSI_ENTRIES,
67 PCI_IRQ_MSIX | PCI_IRQ_MSI);
71 if (mask & (PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP)) {
75 * Per PCIe r3.1, sec 6.1.6, "PME and Hot-Plug Event
76 * interrupts (when both are implemented) always share the
77 * same MSI or MSI-X vector, as indicated by the Interrupt
78 * Message Number field in the PCI Express Capabilities
81 * Per sec 7.8.2, "For MSI, the [Interrupt Message Number]
82 * indicates the offset between the base Message Data and
83 * the interrupt message that is generated."
85 * "For MSI-X, the [Interrupt Message Number] indicates
86 * which MSI-X Table entry is used to generate the
89 pcie_capability_read_word(dev, PCI_EXP_FLAGS, ®16);
90 entry = (reg16 & PCI_EXP_FLAGS_IRQ) >> 9;
91 if (entry >= nr_entries)
94 irqs[PCIE_PORT_SERVICE_PME_SHIFT] = pci_irq_vector(dev, entry);
95 irqs[PCIE_PORT_SERVICE_HP_SHIFT] = pci_irq_vector(dev, entry);
97 nvec = max(nvec, entry + 1);
100 if (mask & PCIE_PORT_SERVICE_AER) {
104 * Per PCIe r3.1, sec 7.10.10, the Advanced Error Interrupt
105 * Message Number in the Root Error Status register
106 * indicates which MSI/MSI-X vector is used for AER.
108 * "For MSI, the [Advanced Error Interrupt Message Number]
109 * indicates the offset between the base Message Data and
110 * the interrupt message that is generated."
112 * "For MSI-X, the [Advanced Error Interrupt Message
113 * Number] indicates which MSI-X Table entry is used to
114 * generate the interrupt message."
116 pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
117 pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, ®32);
119 if (entry >= nr_entries)
122 irqs[PCIE_PORT_SERVICE_AER_SHIFT] = pci_irq_vector(dev, entry);
124 nvec = max(nvec, entry + 1);
127 if (mask & PCIE_PORT_SERVICE_DPC) {
131 * Per PCIe r4.0 (v0.9), sec 7.9.15.2, the DPC Interrupt
132 * Message Number in the DPC Capability register indicates
133 * which MSI/MSI-X vector is used for DPC.
135 * "For MSI, the [DPC Interrupt Message Number] indicates
136 * the offset between the base Message Data and the
137 * interrupt message that is generated."
139 * "For MSI-X, the [DPC Interrupt Message Number] indicates
140 * which MSI-X Table entry is used to generate the
141 * interrupt message."
143 pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC);
144 pci_read_config_word(dev, pos + PCI_EXP_DPC_CAP, ®16);
145 entry = reg16 & 0x1f;
146 if (entry >= nr_entries)
149 irqs[PCIE_PORT_SERVICE_DPC_SHIFT] = pci_irq_vector(dev, entry);
151 nvec = max(nvec, entry + 1);
155 * If nvec is equal to the allocated number of entries, we can just use
156 * what we have. Otherwise, the port has some extra entries not for the
157 * services we know and we need to work around that.
159 if (nvec != nr_entries) {
160 /* Drop the temporary MSI-X setup */
161 pci_free_irq_vectors(dev);
163 /* Now allocate the MSI-X vectors for real */
164 nr_entries = pci_alloc_irq_vectors(dev, nvec, nvec,
165 PCI_IRQ_MSIX | PCI_IRQ_MSI);
173 pci_free_irq_vectors(dev);
178 * pcie_init_service_irqs - initialize irqs for PCI Express port services
179 * @dev: PCI Express port to handle
180 * @irqs: Array of irqs to populate
181 * @mask: Bitmask of port capabilities returned by get_port_device_capability()
183 * Return value: Interrupt mode associated with the port
185 static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
189 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++)
193 * If we support PME or hotplug, but we can't use MSI/MSI-X for
194 * them, we have to fall back to INTx or other interrupts, e.g., a
195 * system shared interrupt.
197 if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
200 if ((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi())
203 /* Try to use MSI-X or MSI if supported */
204 if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
208 /* fall back to legacy IRQ */
209 ret = pci_alloc_irq_vectors(dev, 1, 1, PCI_IRQ_LEGACY);
213 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
214 if (i != PCIE_PORT_SERVICE_VC_SHIFT)
215 irqs[i] = pci_irq_vector(dev, 0);
222 * get_port_device_capability - discover capabilities of a PCI Express port
223 * @dev: PCI Express port to examine
225 * The capabilities are read from the port's PCI Express configuration registers
226 * as described in PCI Express Base Specification 1.0a sections 7.8.2, 7.8.9 and
229 * Return value: Bitmask of discovered port capabilities
231 static int get_port_device_capability(struct pci_dev *dev)
236 if (pcie_ports_disabled)
239 cap_mask = PCIE_PORT_SERVICE_PME | PCIE_PORT_SERVICE_HP
240 | PCIE_PORT_SERVICE_VC | PCIE_PORT_SERVICE_DPC;
241 if (pci_aer_available())
242 cap_mask |= PCIE_PORT_SERVICE_AER;
245 pcie_port_platform_notify(dev, &cap_mask);
247 /* Hot-Plug Capable */
248 if ((cap_mask & PCIE_PORT_SERVICE_HP) && dev->is_hotplug_bridge) {
249 services |= PCIE_PORT_SERVICE_HP;
251 * Disable hot-plug interrupts in case they have been enabled
252 * by the BIOS and the hot-plug service driver is not loaded.
254 pcie_capability_clear_word(dev, PCI_EXP_SLTCTL,
255 PCI_EXP_SLTCTL_CCIE | PCI_EXP_SLTCTL_HPIE);
258 if ((cap_mask & PCIE_PORT_SERVICE_AER)
259 && pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR)) {
260 services |= PCIE_PORT_SERVICE_AER;
262 * Disable AER on this port in case it's been enabled by the
263 * BIOS (the AER service driver will enable it when necessary).
265 pci_disable_pcie_error_reporting(dev);
268 if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_VC))
269 services |= PCIE_PORT_SERVICE_VC;
270 /* Root ports are capable of generating PME too */
271 if ((cap_mask & PCIE_PORT_SERVICE_PME)
272 && pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) {
273 services |= PCIE_PORT_SERVICE_PME;
275 * Disable PME interrupt on this port in case it's been enabled
276 * by the BIOS (the PME service driver will enable it when
279 pcie_pme_interrupt_enable(dev, false);
281 if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_DPC))
282 services |= PCIE_PORT_SERVICE_DPC;
288 * pcie_device_init - allocate and initialize PCI Express port service device
289 * @pdev: PCI Express port to associate the service device with
290 * @service: Type of service to associate with the service device
291 * @irq: Interrupt vector to associate with the service device
293 static int pcie_device_init(struct pci_dev *pdev, int service, int irq)
296 struct pcie_device *pcie;
297 struct device *device;
299 pcie = kzalloc(sizeof(*pcie), GFP_KERNEL);
304 pcie->service = service;
306 /* Initialize generic device interface */
307 device = &pcie->device;
308 device->bus = &pcie_port_bus_type;
309 device->release = release_pcie_device; /* callback to free pcie dev */
310 dev_set_name(device, "%s:pcie%03x",
312 get_descriptor_id(pci_pcie_type(pdev), service));
313 device->parent = &pdev->dev;
314 device_enable_async_suspend(device);
316 retval = device_register(device);
322 pm_runtime_no_callbacks(device);
328 * pcie_port_device_register - register PCI Express port
329 * @dev: PCI Express port to register
331 * Allocate the port extension structure and register services associated with
334 int pcie_port_device_register(struct pci_dev *dev)
336 int status, capabilities, i, nr_service;
337 int irqs[PCIE_PORT_DEVICE_MAXSERVICES];
339 /* Enable PCI Express port device */
340 status = pci_enable_device(dev);
344 /* Get and check PCI Express port services */
345 capabilities = get_port_device_capability(dev);
351 * Initialize service irqs. Don't use service devices that
352 * require interrupts if there is no way to generate them.
353 * However, some drivers may have a polling mode (e.g. pciehp_poll_mode)
354 * that can be used in the absence of irqs. Allow them to determine
355 * if that is to be used.
357 status = pcie_init_service_irqs(dev, irqs, capabilities);
359 capabilities &= PCIE_PORT_SERVICE_VC | PCIE_PORT_SERVICE_HP;
364 /* Allocate child services if any */
367 for (i = 0; i < PCIE_PORT_DEVICE_MAXSERVICES; i++) {
368 int service = 1 << i;
369 if (!(capabilities & service))
371 if (!pcie_device_init(dev, service, irqs[i]))
375 goto error_cleanup_irqs;
380 pci_free_irq_vectors(dev);
382 pci_disable_device(dev);
387 static int suspend_iter(struct device *dev, void *data)
389 struct pcie_port_service_driver *service_driver;
391 if ((dev->bus == &pcie_port_bus_type) && dev->driver) {
392 service_driver = to_service_driver(dev->driver);
393 if (service_driver->suspend)
394 service_driver->suspend(to_pcie_device(dev));
400 * pcie_port_device_suspend - suspend port services associated with a PCIe port
401 * @dev: PCI Express port to handle
403 int pcie_port_device_suspend(struct device *dev)
405 return device_for_each_child(dev, NULL, suspend_iter);
408 static int resume_iter(struct device *dev, void *data)
410 struct pcie_port_service_driver *service_driver;
412 if ((dev->bus == &pcie_port_bus_type) &&
414 service_driver = to_service_driver(dev->driver);
415 if (service_driver->resume)
416 service_driver->resume(to_pcie_device(dev));
422 * pcie_port_device_resume - resume port services associated with a PCIe port
423 * @dev: PCI Express port to handle
425 int pcie_port_device_resume(struct device *dev)
427 return device_for_each_child(dev, NULL, resume_iter);
431 static int remove_iter(struct device *dev, void *data)
433 if (dev->bus == &pcie_port_bus_type)
434 device_unregister(dev);
439 * pcie_port_device_remove - unregister PCI Express port service devices
440 * @dev: PCI Express port the service devices to unregister are associated with
442 * Remove PCI Express port service devices associated with given port and
443 * disable MSI-X or MSI for the port.
445 void pcie_port_device_remove(struct pci_dev *dev)
447 device_for_each_child(&dev->dev, NULL, remove_iter);
448 pci_free_irq_vectors(dev);
449 pci_disable_device(dev);
453 * pcie_port_probe_service - probe driver for given PCI Express port service
454 * @dev: PCI Express port service device to probe against
456 * If PCI Express port service driver is registered with
457 * pcie_port_service_register(), this function will be called by the driver core
458 * whenever match is found between the driver and a port service device.
460 static int pcie_port_probe_service(struct device *dev)
462 struct pcie_device *pciedev;
463 struct pcie_port_service_driver *driver;
466 if (!dev || !dev->driver)
469 driver = to_service_driver(dev->driver);
470 if (!driver || !driver->probe)
473 pciedev = to_pcie_device(dev);
474 status = driver->probe(pciedev);
483 * pcie_port_remove_service - detach driver from given PCI Express port service
484 * @dev: PCI Express port service device to handle
486 * If PCI Express port service driver is registered with
487 * pcie_port_service_register(), this function will be called by the driver core
488 * when device_unregister() is called for the port service device associated
491 static int pcie_port_remove_service(struct device *dev)
493 struct pcie_device *pciedev;
494 struct pcie_port_service_driver *driver;
496 if (!dev || !dev->driver)
499 pciedev = to_pcie_device(dev);
500 driver = to_service_driver(dev->driver);
501 if (driver && driver->remove) {
502 driver->remove(pciedev);
509 * pcie_port_shutdown_service - shut down given PCI Express port service
510 * @dev: PCI Express port service device to handle
512 * If PCI Express port service driver is registered with
513 * pcie_port_service_register(), this function will be called by the driver core
514 * when device_shutdown() is called for the port service device associated
517 static void pcie_port_shutdown_service(struct device *dev) {}
520 * pcie_port_service_register - register PCI Express port service driver
521 * @new: PCI Express port service driver to register
523 int pcie_port_service_register(struct pcie_port_service_driver *new)
525 if (pcie_ports_disabled)
528 new->driver.name = new->name;
529 new->driver.bus = &pcie_port_bus_type;
530 new->driver.probe = pcie_port_probe_service;
531 new->driver.remove = pcie_port_remove_service;
532 new->driver.shutdown = pcie_port_shutdown_service;
534 return driver_register(&new->driver);
536 EXPORT_SYMBOL(pcie_port_service_register);
539 * pcie_port_service_unregister - unregister PCI Express port service driver
540 * @drv: PCI Express port service driver to unregister
542 void pcie_port_service_unregister(struct pcie_port_service_driver *drv)
544 driver_unregister(&drv->driver);
546 EXPORT_SYMBOL(pcie_port_service_unregister);