1 // SPDX-License-Identifier: GPL-2.0
3 * PCIe Native PME support
5 * Copyright (C) 2007 - 2009 Intel Corp
10 #define dev_fmt(fmt) "PME: " fmt
12 #include <linux/bitfield.h>
13 #include <linux/pci.h>
14 #include <linux/kernel.h>
15 #include <linux/errno.h>
16 #include <linux/slab.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/device.h>
20 #include <linux/pm_runtime.h>
26 * If this switch is set, MSI will not be used for PCIe PME signaling. This
27 * causes the PCIe port driver to use INTx interrupts only, but it turns out
28 * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
29 * wake-up from system sleep states.
31 bool pcie_pme_msi_disabled;
33 static int __init pcie_pme_setup(char *str)
35 if (!strncmp(str, "nomsi", 5))
36 pcie_pme_msi_disabled = true;
40 __setup("pcie_pme=", pcie_pme_setup);
42 struct pcie_pme_service_data {
44 struct pcie_device *srv;
45 struct work_struct work;
46 bool noirq; /* If set, keep the PME interrupt disabled. */
50 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
51 * @dev: PCIe root port or event collector.
52 * @enable: Enable or disable the interrupt.
54 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
57 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
60 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
65 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
66 * @bus: PCI bus to scan.
68 * Scan given PCI bus and all buses under it for devices asserting PME#.
70 static bool pcie_pme_walk_bus(struct pci_bus *bus)
75 list_for_each_entry(dev, &bus->devices, bus_list) {
76 /* Skip PCIe devices in case we started from a root port. */
77 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
79 dev->pme_poll = false;
81 pci_wakeup_event(dev);
82 pm_request_resume(&dev->dev);
86 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
94 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
95 * @bus: Secondary bus of the bridge.
96 * @devfn: Device/function number to check.
98 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
99 * PCIe PME message. In such that case the bridge should use the Requester ID
100 * of device/function number 0 on its secondary bus.
102 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
110 dev = pci_dev_get(bus->self);
114 if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
115 down_read(&pci_bus_sem);
116 if (pcie_pme_walk_bus(bus))
118 up_read(&pci_bus_sem);
126 * pcie_pme_handle_request - Find device that generated PME and handle it.
127 * @port: Root port or event collector that generated the PME interrupt.
128 * @req_id: PCIe Requester ID of the device that generated the PME.
130 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
132 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
137 /* First, check if the PME is from the root port itself. */
138 if (port->devfn == devfn && port->bus->number == busnr) {
140 port->pme_poll = false;
142 if (pci_check_pme_status(port)) {
143 pm_request_resume(&port->dev);
147 * Apparently, the root port generated the PME on behalf
148 * of a non-PCIe device downstream. If this is done by
149 * a root port, the Requester ID field in its status
150 * register may contain either the root port's, or the
151 * source device's information (PCI Express Base
152 * Specification, Rev. 2.0, Section 6.1.9).
154 down_read(&pci_bus_sem);
155 found = pcie_pme_walk_bus(port->subordinate);
156 up_read(&pci_bus_sem);
161 /* Second, find the bus the source device is on. */
162 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
166 /* Next, check if the PME is from a PCIe-PCI bridge. */
167 found = pcie_pme_from_pci_bridge(bus, devfn);
171 /* Finally, try to find the PME source on the bus. */
172 down_read(&pci_bus_sem);
173 list_for_each_entry(dev, &bus->devices, bus_list) {
175 if (dev->devfn == devfn) {
181 up_read(&pci_bus_sem);
184 /* The device is there, but we have to check its PME status. */
185 found = pci_check_pme_status(dev);
188 dev->pme_poll = false;
190 pci_wakeup_event(dev);
191 pm_request_resume(&dev->dev);
196 * The device is not there, but we can still try to recover by
197 * assuming that the PME was reported by a PCIe-PCI bridge that
198 * used devfn different from zero.
200 pci_info(port, "interrupt generated for non-existent device %02x:%02x.%d\n",
201 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
202 found = pcie_pme_from_pci_bridge(bus, 0);
207 pci_info(port, "Spurious native interrupt!\n");
211 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
212 * @work: Work structure giving access to service data.
214 static void pcie_pme_work_fn(struct work_struct *work)
216 struct pcie_pme_service_data *data =
217 container_of(work, struct pcie_pme_service_data, work);
218 struct pci_dev *port = data->srv->port;
221 spin_lock_irq(&data->lock);
227 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
228 if (PCI_POSSIBLE_ERROR(rtsta))
231 if (rtsta & PCI_EXP_RTSTA_PME) {
233 * Clear PME status of the port. If there are other
234 * pending PMEs, the status will be set again.
236 pcie_clear_root_pme_status(port);
238 spin_unlock_irq(&data->lock);
239 pcie_pme_handle_request(port,
240 FIELD_GET(PCI_EXP_RTSTA_PME_RQ_ID, rtsta));
241 spin_lock_irq(&data->lock);
246 /* No need to loop if there are no more PMEs pending. */
247 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
250 spin_unlock_irq(&data->lock);
252 spin_lock_irq(&data->lock);
256 pcie_pme_interrupt_enable(port, true);
258 spin_unlock_irq(&data->lock);
262 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
263 * @irq: Interrupt vector.
264 * @context: Interrupt context pointer.
266 static irqreturn_t pcie_pme_irq(int irq, void *context)
268 struct pci_dev *port;
269 struct pcie_pme_service_data *data;
273 port = ((struct pcie_device *)context)->port;
274 data = get_service_data((struct pcie_device *)context);
276 spin_lock_irqsave(&data->lock, flags);
277 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
279 if (PCI_POSSIBLE_ERROR(rtsta) || !(rtsta & PCI_EXP_RTSTA_PME)) {
280 spin_unlock_irqrestore(&data->lock, flags);
284 pcie_pme_interrupt_enable(port, false);
285 spin_unlock_irqrestore(&data->lock, flags);
287 /* We don't use pm_wq, because it's freezable. */
288 schedule_work(&data->work);
294 * pcie_pme_can_wakeup - Set the wakeup capability flag.
295 * @dev: PCI device to handle.
298 static int pcie_pme_can_wakeup(struct pci_dev *dev, void *ign)
300 device_set_wakeup_capable(&dev->dev, true);
305 * pcie_pme_mark_devices - Set the wakeup flag for devices below a port.
306 * @port: PCIe root port or event collector to handle.
308 * For each device below given root port, including the port itself (or for each
309 * root complex integrated endpoint if @port is a root complex event collector)
310 * set the flag indicating that it can signal run-time wake-up events.
312 static void pcie_pme_mark_devices(struct pci_dev *port)
314 pcie_pme_can_wakeup(port, NULL);
316 if (pci_pcie_type(port) == PCI_EXP_TYPE_RC_EC)
317 pcie_walk_rcec(port, pcie_pme_can_wakeup, NULL);
318 else if (port->subordinate)
319 pci_walk_bus(port->subordinate, pcie_pme_can_wakeup, NULL);
323 * pcie_pme_probe - Initialize PCIe PME service for given root port.
324 * @srv: PCIe service to initialize.
326 static int pcie_pme_probe(struct pcie_device *srv)
328 struct pci_dev *port = srv->port;
329 struct pcie_pme_service_data *data;
330 int type = pci_pcie_type(port);
333 /* Limit to Root Ports or Root Complex Event Collectors */
334 if (type != PCI_EXP_TYPE_RC_EC &&
335 type != PCI_EXP_TYPE_ROOT_PORT)
338 data = kzalloc(sizeof(*data), GFP_KERNEL);
342 spin_lock_init(&data->lock);
343 INIT_WORK(&data->work, pcie_pme_work_fn);
345 set_service_data(srv, data);
347 pcie_pme_interrupt_enable(port, false);
348 pcie_clear_root_pme_status(port);
350 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
356 pci_info(port, "Signaling with IRQ %d\n", srv->irq);
358 pcie_pme_mark_devices(port);
359 pcie_pme_interrupt_enable(port, true);
363 static bool pcie_pme_check_wakeup(struct pci_bus *bus)
370 list_for_each_entry(dev, &bus->devices, bus_list)
371 if (device_may_wakeup(&dev->dev)
372 || pcie_pme_check_wakeup(dev->subordinate))
378 static void pcie_pme_disable_interrupt(struct pci_dev *port,
379 struct pcie_pme_service_data *data)
381 spin_lock_irq(&data->lock);
382 pcie_pme_interrupt_enable(port, false);
383 pcie_clear_root_pme_status(port);
385 spin_unlock_irq(&data->lock);
389 * pcie_pme_suspend - Suspend PCIe PME service device.
390 * @srv: PCIe service device to suspend.
392 static int pcie_pme_suspend(struct pcie_device *srv)
394 struct pcie_pme_service_data *data = get_service_data(srv);
395 struct pci_dev *port = srv->port;
399 if (device_may_wakeup(&port->dev)) {
402 down_read(&pci_bus_sem);
403 wakeup = pcie_pme_check_wakeup(port->subordinate);
404 up_read(&pci_bus_sem);
407 ret = enable_irq_wake(srv->irq);
412 pcie_pme_disable_interrupt(port, data);
414 synchronize_irq(srv->irq);
420 * pcie_pme_resume - Resume PCIe PME service device.
421 * @srv: PCIe service device to resume.
423 static int pcie_pme_resume(struct pcie_device *srv)
425 struct pcie_pme_service_data *data = get_service_data(srv);
427 spin_lock_irq(&data->lock);
429 struct pci_dev *port = srv->port;
431 pcie_clear_root_pme_status(port);
432 pcie_pme_interrupt_enable(port, true);
435 disable_irq_wake(srv->irq);
437 spin_unlock_irq(&data->lock);
443 * pcie_pme_remove - Prepare PCIe PME service device for removal.
444 * @srv: PCIe service device to remove.
446 static void pcie_pme_remove(struct pcie_device *srv)
448 struct pcie_pme_service_data *data = get_service_data(srv);
450 pcie_pme_disable_interrupt(srv->port, data);
451 free_irq(srv->irq, srv);
452 cancel_work_sync(&data->work);
456 static struct pcie_port_service_driver pcie_pme_driver = {
458 .port_type = PCIE_ANY_PORT,
459 .service = PCIE_PORT_SERVICE_PME,
461 .probe = pcie_pme_probe,
462 .suspend = pcie_pme_suspend,
463 .resume = pcie_pme_resume,
464 .remove = pcie_pme_remove,
468 * pcie_pme_init - Register the PCIe PME service driver.
470 int __init pcie_pme_init(void)
472 return pcie_port_service_register(&pcie_pme_driver);