2 * PCIe Native PME support
4 * Copyright (C) 2007 - 2009 Intel Corp
5 * Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
6 * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License V2. See the file "COPYING" in the main directory of this archive
13 #include <linux/module.h>
14 #include <linux/pci.h>
15 #include <linux/kernel.h>
16 #include <linux/errno.h>
17 #include <linux/slab.h>
18 #include <linux/init.h>
19 #include <linux/interrupt.h>
20 #include <linux/device.h>
21 #include <linux/pcieport_if.h>
22 #include <linux/pm_runtime.h>
28 * If this switch is set, MSI will not be used for PCIe PME signaling. This
29 * causes the PCIe port driver to use INTx interrupts only, but it turns out
30 * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
31 * wake-up from system sleep states.
33 bool pcie_pme_msi_disabled;
35 static int __init pcie_pme_setup(char *str)
37 if (!strncmp(str, "nomsi", 5))
38 pcie_pme_msi_disabled = true;
42 __setup("pcie_pme=", pcie_pme_setup);
44 struct pcie_pme_service_data {
46 struct pcie_device *srv;
47 struct work_struct work;
48 bool noirq; /* Don't enable the PME interrupt used by this service. */
52 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
53 * @dev: PCIe root port or event collector.
54 * @enable: Enable or disable the interrupt.
56 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
59 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
62 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
67 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
68 * @bus: PCI bus to scan.
70 * Scan given PCI bus and all buses under it for devices asserting PME#.
72 static bool pcie_pme_walk_bus(struct pci_bus *bus)
77 list_for_each_entry(dev, &bus->devices, bus_list) {
78 /* Skip PCIe devices in case we started from a root port. */
79 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
81 dev->pme_poll = false;
83 pci_wakeup_event(dev);
84 pm_request_resume(&dev->dev);
88 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
96 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
97 * @bus: Secondary bus of the bridge.
98 * @devfn: Device/function number to check.
100 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
101 * PCIe PME message. In such that case the bridge should use the Requester ID
102 * of device/function number 0 on its secondary bus.
104 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
112 dev = pci_dev_get(bus->self);
116 if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
117 down_read(&pci_bus_sem);
118 if (pcie_pme_walk_bus(bus))
120 up_read(&pci_bus_sem);
128 * pcie_pme_handle_request - Find device that generated PME and handle it.
129 * @port: Root port or event collector that generated the PME interrupt.
130 * @req_id: PCIe Requester ID of the device that generated the PME.
132 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
134 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
139 /* First, check if the PME is from the root port itself. */
140 if (port->devfn == devfn && port->bus->number == busnr) {
142 port->pme_poll = false;
144 if (pci_check_pme_status(port)) {
145 pm_request_resume(&port->dev);
149 * Apparently, the root port generated the PME on behalf
150 * of a non-PCIe device downstream. If this is done by
151 * a root port, the Requester ID field in its status
152 * register may contain either the root port's, or the
153 * source device's information (PCI Express Base
154 * Specification, Rev. 2.0, Section 6.1.9).
156 down_read(&pci_bus_sem);
157 found = pcie_pme_walk_bus(port->subordinate);
158 up_read(&pci_bus_sem);
163 /* Second, find the bus the source device is on. */
164 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
168 /* Next, check if the PME is from a PCIe-PCI bridge. */
169 found = pcie_pme_from_pci_bridge(bus, devfn);
173 /* Finally, try to find the PME source on the bus. */
174 down_read(&pci_bus_sem);
175 list_for_each_entry(dev, &bus->devices, bus_list) {
177 if (dev->devfn == devfn) {
183 up_read(&pci_bus_sem);
186 /* The device is there, but we have to check its PME status. */
187 found = pci_check_pme_status(dev);
190 dev->pme_poll = false;
192 pci_wakeup_event(dev);
193 pm_request_resume(&dev->dev);
198 * The device is not there, but we can still try to recover by
199 * assuming that the PME was reported by a PCIe-PCI bridge that
200 * used devfn different from zero.
202 dev_dbg(&port->dev, "PME interrupt generated for "
203 "non-existent device %02x:%02x.%d\n",
204 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
205 found = pcie_pme_from_pci_bridge(bus, 0);
210 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
214 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
215 * @work: Work structure giving access to service data.
217 static void pcie_pme_work_fn(struct work_struct *work)
219 struct pcie_pme_service_data *data =
220 container_of(work, struct pcie_pme_service_data, work);
221 struct pci_dev *port = data->srv->port;
224 spin_lock_irq(&data->lock);
230 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &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, rtsta & 0xffff);
240 spin_lock_irq(&data->lock);
245 /* No need to loop if there are no more PMEs pending. */
246 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
249 spin_unlock_irq(&data->lock);
251 spin_lock_irq(&data->lock);
255 pcie_pme_interrupt_enable(port, true);
257 spin_unlock_irq(&data->lock);
261 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
262 * @irq: Interrupt vector.
263 * @context: Interrupt context pointer.
265 static irqreturn_t pcie_pme_irq(int irq, void *context)
267 struct pci_dev *port;
268 struct pcie_pme_service_data *data;
272 port = ((struct pcie_device *)context)->port;
273 data = get_service_data((struct pcie_device *)context);
275 spin_lock_irqsave(&data->lock, flags);
276 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
278 if (!(rtsta & PCI_EXP_RTSTA_PME)) {
279 spin_unlock_irqrestore(&data->lock, flags);
283 pcie_pme_interrupt_enable(port, false);
284 spin_unlock_irqrestore(&data->lock, flags);
286 /* We don't use pm_wq, because it's freezable. */
287 schedule_work(&data->work);
293 * pcie_pme_set_native - Set the PME interrupt flag for given device.
294 * @dev: PCI device to handle.
297 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
299 dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
301 device_set_run_wake(&dev->dev, true);
302 dev->pme_interrupt = true;
307 * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
308 * @port: PCIe root port or event collector to handle.
310 * For each device below given root port, including the port itself (or for each
311 * root complex integrated endpoint if @port is a root complex event collector)
312 * set the flag indicating that it can signal run-time wake-up events via PCIe
315 static void pcie_pme_mark_devices(struct pci_dev *port)
317 pcie_pme_set_native(port, NULL);
318 if (port->subordinate) {
319 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
321 struct pci_bus *bus = port->bus;
324 /* Check if this is a root port event collector. */
325 if (pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC || !bus)
328 down_read(&pci_bus_sem);
329 list_for_each_entry(dev, &bus->devices, bus_list)
331 && pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
332 pcie_pme_set_native(dev, NULL);
333 up_read(&pci_bus_sem);
338 * pcie_pme_probe - Initialize PCIe PME service for given root port.
339 * @srv: PCIe service to initialize.
341 static int pcie_pme_probe(struct pcie_device *srv)
343 struct pci_dev *port;
344 struct pcie_pme_service_data *data;
347 data = kzalloc(sizeof(*data), GFP_KERNEL);
351 spin_lock_init(&data->lock);
352 INIT_WORK(&data->work, pcie_pme_work_fn);
354 set_service_data(srv, data);
357 pcie_pme_interrupt_enable(port, false);
358 pcie_clear_root_pme_status(port);
360 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
364 pcie_pme_mark_devices(port);
365 pcie_pme_interrupt_enable(port, true);
372 * pcie_pme_suspend - Suspend PCIe PME service device.
373 * @srv: PCIe service device to suspend.
375 static int pcie_pme_suspend(struct pcie_device *srv)
377 struct pcie_pme_service_data *data = get_service_data(srv);
378 struct pci_dev *port = srv->port;
380 spin_lock_irq(&data->lock);
381 pcie_pme_interrupt_enable(port, false);
382 pcie_clear_root_pme_status(port);
384 spin_unlock_irq(&data->lock);
386 synchronize_irq(srv->irq);
392 * pcie_pme_resume - Resume PCIe PME service device.
393 * @srv - PCIe service device to resume.
395 static int pcie_pme_resume(struct pcie_device *srv)
397 struct pcie_pme_service_data *data = get_service_data(srv);
398 struct pci_dev *port = srv->port;
400 spin_lock_irq(&data->lock);
402 pcie_clear_root_pme_status(port);
403 pcie_pme_interrupt_enable(port, true);
404 spin_unlock_irq(&data->lock);
410 * pcie_pme_remove - Prepare PCIe PME service device for removal.
411 * @srv - PCIe service device to resume.
413 static void pcie_pme_remove(struct pcie_device *srv)
415 pcie_pme_suspend(srv);
416 free_irq(srv->irq, srv);
417 kfree(get_service_data(srv));
420 static struct pcie_port_service_driver pcie_pme_driver = {
422 .port_type = PCI_EXP_TYPE_ROOT_PORT,
423 .service = PCIE_PORT_SERVICE_PME,
425 .probe = pcie_pme_probe,
426 .suspend = pcie_pme_suspend,
427 .resume = pcie_pme_resume,
428 .remove = pcie_pme_remove,
432 * pcie_pme_service_init - Register the PCIe PME service driver.
434 static int __init pcie_pme_service_init(void)
436 return pcie_port_service_register(&pcie_pme_driver);
439 module_init(pcie_pme_service_init);