1 // SPDX-License-Identifier: GPL-2.0
3 * PCIe Native PME support
5 * Copyright (C) 2007 - 2009 Intel Corp
6 * Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
7 * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
10 #include <linux/pci.h>
11 #include <linux/kernel.h>
12 #include <linux/errno.h>
13 #include <linux/slab.h>
14 #include <linux/init.h>
15 #include <linux/interrupt.h>
16 #include <linux/device.h>
17 #include <linux/pcieport_if.h>
18 #include <linux/pm_runtime.h>
24 * If this switch is set, MSI will not be used for PCIe PME signaling. This
25 * causes the PCIe port driver to use INTx interrupts only, but it turns out
26 * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
27 * wake-up from system sleep states.
29 bool pcie_pme_msi_disabled;
31 static int __init pcie_pme_setup(char *str)
33 if (!strncmp(str, "nomsi", 5))
34 pcie_pme_msi_disabled = true;
38 __setup("pcie_pme=", pcie_pme_setup);
40 struct pcie_pme_service_data {
42 struct pcie_device *srv;
43 struct work_struct work;
44 bool noirq; /* If set, keep the PME interrupt disabled. */
48 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
49 * @dev: PCIe root port or event collector.
50 * @enable: Enable or disable the interrupt.
52 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
55 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
58 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
63 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
64 * @bus: PCI bus to scan.
66 * Scan given PCI bus and all buses under it for devices asserting PME#.
68 static bool pcie_pme_walk_bus(struct pci_bus *bus)
73 list_for_each_entry(dev, &bus->devices, bus_list) {
74 /* Skip PCIe devices in case we started from a root port. */
75 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
77 dev->pme_poll = false;
79 pci_wakeup_event(dev);
80 pm_request_resume(&dev->dev);
84 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
92 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
93 * @bus: Secondary bus of the bridge.
94 * @devfn: Device/function number to check.
96 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
97 * PCIe PME message. In such that case the bridge should use the Requester ID
98 * of device/function number 0 on its secondary bus.
100 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
108 dev = pci_dev_get(bus->self);
112 if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
113 down_read(&pci_bus_sem);
114 if (pcie_pme_walk_bus(bus))
116 up_read(&pci_bus_sem);
124 * pcie_pme_handle_request - Find device that generated PME and handle it.
125 * @port: Root port or event collector that generated the PME interrupt.
126 * @req_id: PCIe Requester ID of the device that generated the PME.
128 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
130 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
135 /* First, check if the PME is from the root port itself. */
136 if (port->devfn == devfn && port->bus->number == busnr) {
138 port->pme_poll = false;
140 if (pci_check_pme_status(port)) {
141 pm_request_resume(&port->dev);
145 * Apparently, the root port generated the PME on behalf
146 * of a non-PCIe device downstream. If this is done by
147 * a root port, the Requester ID field in its status
148 * register may contain either the root port's, or the
149 * source device's information (PCI Express Base
150 * Specification, Rev. 2.0, Section 6.1.9).
152 down_read(&pci_bus_sem);
153 found = pcie_pme_walk_bus(port->subordinate);
154 up_read(&pci_bus_sem);
159 /* Second, find the bus the source device is on. */
160 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
164 /* Next, check if the PME is from a PCIe-PCI bridge. */
165 found = pcie_pme_from_pci_bridge(bus, devfn);
169 /* Finally, try to find the PME source on the bus. */
170 down_read(&pci_bus_sem);
171 list_for_each_entry(dev, &bus->devices, bus_list) {
173 if (dev->devfn == devfn) {
179 up_read(&pci_bus_sem);
182 /* The device is there, but we have to check its PME status. */
183 found = pci_check_pme_status(dev);
186 dev->pme_poll = false;
188 pci_wakeup_event(dev);
189 pm_request_resume(&dev->dev);
194 * The device is not there, but we can still try to recover by
195 * assuming that the PME was reported by a PCIe-PCI bridge that
196 * used devfn different from zero.
198 pci_dbg(port, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
199 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
200 found = pcie_pme_from_pci_bridge(bus, 0);
205 pci_dbg(port, "Spurious native PME interrupt!\n");
209 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
210 * @work: Work structure giving access to service data.
212 static void pcie_pme_work_fn(struct work_struct *work)
214 struct pcie_pme_service_data *data =
215 container_of(work, struct pcie_pme_service_data, work);
216 struct pci_dev *port = data->srv->port;
219 spin_lock_irq(&data->lock);
225 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
226 if (rtsta == (u32) ~0)
229 if (rtsta & PCI_EXP_RTSTA_PME) {
231 * Clear PME status of the port. If there are other
232 * pending PMEs, the status will be set again.
234 pcie_clear_root_pme_status(port);
236 spin_unlock_irq(&data->lock);
237 pcie_pme_handle_request(port, rtsta & 0xffff);
238 spin_lock_irq(&data->lock);
243 /* No need to loop if there are no more PMEs pending. */
244 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
247 spin_unlock_irq(&data->lock);
249 spin_lock_irq(&data->lock);
253 pcie_pme_interrupt_enable(port, true);
255 spin_unlock_irq(&data->lock);
259 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
260 * @irq: Interrupt vector.
261 * @context: Interrupt context pointer.
263 static irqreturn_t pcie_pme_irq(int irq, void *context)
265 struct pci_dev *port;
266 struct pcie_pme_service_data *data;
270 port = ((struct pcie_device *)context)->port;
271 data = get_service_data((struct pcie_device *)context);
273 spin_lock_irqsave(&data->lock, flags);
274 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
276 if (rtsta == (u32) ~0 || !(rtsta & PCI_EXP_RTSTA_PME)) {
277 spin_unlock_irqrestore(&data->lock, flags);
281 pcie_pme_interrupt_enable(port, false);
282 spin_unlock_irqrestore(&data->lock, flags);
284 /* We don't use pm_wq, because it's freezable. */
285 schedule_work(&data->work);
291 * pcie_pme_can_wakeup - Set the wakeup capability flag.
292 * @dev: PCI device to handle.
295 static int pcie_pme_can_wakeup(struct pci_dev *dev, void *ign)
297 device_set_wakeup_capable(&dev->dev, true);
302 * pcie_pme_mark_devices - Set the wakeup flag for devices below a port.
303 * @port: PCIe root port or event collector to handle.
305 * For each device below given root port, including the port itself (or for each
306 * root complex integrated endpoint if @port is a root complex event collector)
307 * set the flag indicating that it can signal run-time wake-up events.
309 static void pcie_pme_mark_devices(struct pci_dev *port)
311 pcie_pme_can_wakeup(port, NULL);
312 if (port->subordinate)
313 pci_walk_bus(port->subordinate, pcie_pme_can_wakeup, NULL);
317 * pcie_pme_probe - Initialize PCIe PME service for given root port.
318 * @srv: PCIe service to initialize.
320 static int pcie_pme_probe(struct pcie_device *srv)
322 struct pci_dev *port;
323 struct pcie_pme_service_data *data;
326 data = kzalloc(sizeof(*data), GFP_KERNEL);
330 spin_lock_init(&data->lock);
331 INIT_WORK(&data->work, pcie_pme_work_fn);
333 set_service_data(srv, data);
336 pcie_pme_interrupt_enable(port, false);
337 pcie_clear_root_pme_status(port);
339 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
345 pci_info(port, "Signaling PME with IRQ %d\n", srv->irq);
347 pcie_pme_mark_devices(port);
348 pcie_pme_interrupt_enable(port, true);
352 static bool pcie_pme_check_wakeup(struct pci_bus *bus)
359 list_for_each_entry(dev, &bus->devices, bus_list)
360 if (device_may_wakeup(&dev->dev)
361 || pcie_pme_check_wakeup(dev->subordinate))
368 * pcie_pme_suspend - Suspend PCIe PME service device.
369 * @srv: PCIe service device to suspend.
371 static int pcie_pme_suspend(struct pcie_device *srv)
373 struct pcie_pme_service_data *data = get_service_data(srv);
374 struct pci_dev *port = srv->port;
378 if (device_may_wakeup(&port->dev)) {
381 down_read(&pci_bus_sem);
382 wakeup = pcie_pme_check_wakeup(port->subordinate);
383 up_read(&pci_bus_sem);
386 ret = enable_irq_wake(srv->irq);
391 spin_lock_irq(&data->lock);
392 pcie_pme_interrupt_enable(port, false);
393 pcie_clear_root_pme_status(port);
395 spin_unlock_irq(&data->lock);
397 synchronize_irq(srv->irq);
403 * pcie_pme_resume - Resume PCIe PME service device.
404 * @srv - PCIe service device to resume.
406 static int pcie_pme_resume(struct pcie_device *srv)
408 struct pcie_pme_service_data *data = get_service_data(srv);
410 spin_lock_irq(&data->lock);
412 struct pci_dev *port = srv->port;
414 pcie_clear_root_pme_status(port);
415 pcie_pme_interrupt_enable(port, true);
418 disable_irq_wake(srv->irq);
420 spin_unlock_irq(&data->lock);
426 * pcie_pme_remove - Prepare PCIe PME service device for removal.
427 * @srv - PCIe service device to remove.
429 static void pcie_pme_remove(struct pcie_device *srv)
431 pcie_pme_suspend(srv);
432 free_irq(srv->irq, srv);
433 kfree(get_service_data(srv));
436 static struct pcie_port_service_driver pcie_pme_driver = {
438 .port_type = PCI_EXP_TYPE_ROOT_PORT,
439 .service = PCIE_PORT_SERVICE_PME,
441 .probe = pcie_pme_probe,
442 .suspend = pcie_pme_suspend,
443 .resume = pcie_pme_resume,
444 .remove = pcie_pme_remove,
448 * pcie_pme_service_init - Register the PCIe PME service driver.
450 static int __init pcie_pme_service_init(void)
452 return pcie_port_service_register(&pcie_pme_driver);
454 device_initcall(pcie_pme_service_init);