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 enum pme_suspend_level {
50 struct pcie_pme_service_data {
52 struct pcie_device *srv;
53 struct work_struct work;
54 enum pme_suspend_level suspend_level;
58 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
59 * @dev: PCIe root port or event collector.
60 * @enable: Enable or disable the interrupt.
62 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
65 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
68 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
73 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
74 * @bus: PCI bus to scan.
76 * Scan given PCI bus and all buses under it for devices asserting PME#.
78 static bool pcie_pme_walk_bus(struct pci_bus *bus)
83 list_for_each_entry(dev, &bus->devices, bus_list) {
84 /* Skip PCIe devices in case we started from a root port. */
85 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
87 dev->pme_poll = false;
89 pci_wakeup_event(dev);
90 pm_request_resume(&dev->dev);
94 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
102 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
103 * @bus: Secondary bus of the bridge.
104 * @devfn: Device/function number to check.
106 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
107 * PCIe PME message. In such that case the bridge should use the Requester ID
108 * of device/function number 0 on its secondary bus.
110 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
118 dev = pci_dev_get(bus->self);
122 if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
123 down_read(&pci_bus_sem);
124 if (pcie_pme_walk_bus(bus))
126 up_read(&pci_bus_sem);
134 * pcie_pme_handle_request - Find device that generated PME and handle it.
135 * @port: Root port or event collector that generated the PME interrupt.
136 * @req_id: PCIe Requester ID of the device that generated the PME.
138 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
140 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
145 /* First, check if the PME is from the root port itself. */
146 if (port->devfn == devfn && port->bus->number == busnr) {
148 port->pme_poll = false;
150 if (pci_check_pme_status(port)) {
151 pm_request_resume(&port->dev);
155 * Apparently, the root port generated the PME on behalf
156 * of a non-PCIe device downstream. If this is done by
157 * a root port, the Requester ID field in its status
158 * register may contain either the root port's, or the
159 * source device's information (PCI Express Base
160 * Specification, Rev. 2.0, Section 6.1.9).
162 down_read(&pci_bus_sem);
163 found = pcie_pme_walk_bus(port->subordinate);
164 up_read(&pci_bus_sem);
169 /* Second, find the bus the source device is on. */
170 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
174 /* Next, check if the PME is from a PCIe-PCI bridge. */
175 found = pcie_pme_from_pci_bridge(bus, devfn);
179 /* Finally, try to find the PME source on the bus. */
180 down_read(&pci_bus_sem);
181 list_for_each_entry(dev, &bus->devices, bus_list) {
183 if (dev->devfn == devfn) {
189 up_read(&pci_bus_sem);
192 /* The device is there, but we have to check its PME status. */
193 found = pci_check_pme_status(dev);
196 dev->pme_poll = false;
198 pci_wakeup_event(dev);
199 pm_request_resume(&dev->dev);
204 * The device is not there, but we can still try to recover by
205 * assuming that the PME was reported by a PCIe-PCI bridge that
206 * used devfn different from zero.
208 dev_dbg(&port->dev, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
209 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
210 found = pcie_pme_from_pci_bridge(bus, 0);
215 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
219 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
220 * @work: Work structure giving access to service data.
222 static void pcie_pme_work_fn(struct work_struct *work)
224 struct pcie_pme_service_data *data =
225 container_of(work, struct pcie_pme_service_data, work);
226 struct pci_dev *port = data->srv->port;
229 spin_lock_irq(&data->lock);
232 if (data->suspend_level != PME_SUSPEND_NONE)
235 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
236 if (rtsta == (u32) ~0)
239 if (rtsta & PCI_EXP_RTSTA_PME) {
241 * Clear PME status of the port. If there are other
242 * pending PMEs, the status will be set again.
244 pcie_clear_root_pme_status(port);
246 spin_unlock_irq(&data->lock);
247 pcie_pme_handle_request(port, rtsta & 0xffff);
248 spin_lock_irq(&data->lock);
253 /* No need to loop if there are no more PMEs pending. */
254 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
257 spin_unlock_irq(&data->lock);
259 spin_lock_irq(&data->lock);
262 if (data->suspend_level == PME_SUSPEND_NONE)
263 pcie_pme_interrupt_enable(port, true);
265 spin_unlock_irq(&data->lock);
269 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
270 * @irq: Interrupt vector.
271 * @context: Interrupt context pointer.
273 static irqreturn_t pcie_pme_irq(int irq, void *context)
275 struct pci_dev *port;
276 struct pcie_pme_service_data *data;
280 port = ((struct pcie_device *)context)->port;
281 data = get_service_data((struct pcie_device *)context);
283 spin_lock_irqsave(&data->lock, flags);
284 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
286 if (rtsta == (u32) ~0 || !(rtsta & PCI_EXP_RTSTA_PME)) {
287 spin_unlock_irqrestore(&data->lock, flags);
291 pcie_pme_interrupt_enable(port, false);
292 spin_unlock_irqrestore(&data->lock, flags);
294 /* We don't use pm_wq, because it's freezable. */
295 schedule_work(&data->work);
301 * pcie_pme_set_native - Set the PME interrupt flag for given device.
302 * @dev: PCI device to handle.
305 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
307 dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
309 device_set_run_wake(&dev->dev, true);
310 dev->pme_interrupt = true;
315 * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
316 * @port: PCIe root port or event collector to handle.
318 * For each device below given root port, including the port itself (or for each
319 * root complex integrated endpoint if @port is a root complex event collector)
320 * set the flag indicating that it can signal run-time wake-up events via PCIe
323 static void pcie_pme_mark_devices(struct pci_dev *port)
325 pcie_pme_set_native(port, NULL);
326 if (port->subordinate) {
327 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
329 struct pci_bus *bus = port->bus;
332 /* Check if this is a root port event collector. */
333 if (pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC || !bus)
336 down_read(&pci_bus_sem);
337 list_for_each_entry(dev, &bus->devices, bus_list)
339 && pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
340 pcie_pme_set_native(dev, NULL);
341 up_read(&pci_bus_sem);
346 * pcie_pme_probe - Initialize PCIe PME service for given root port.
347 * @srv: PCIe service to initialize.
349 static int pcie_pme_probe(struct pcie_device *srv)
351 struct pci_dev *port;
352 struct pcie_pme_service_data *data;
355 data = kzalloc(sizeof(*data), GFP_KERNEL);
359 spin_lock_init(&data->lock);
360 INIT_WORK(&data->work, pcie_pme_work_fn);
362 set_service_data(srv, data);
365 pcie_pme_interrupt_enable(port, false);
366 pcie_clear_root_pme_status(port);
368 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
372 pcie_pme_mark_devices(port);
373 pcie_pme_interrupt_enable(port, true);
379 static bool pcie_pme_check_wakeup(struct pci_bus *bus)
386 list_for_each_entry(dev, &bus->devices, bus_list)
387 if (device_may_wakeup(&dev->dev)
388 || pcie_pme_check_wakeup(dev->subordinate))
395 * pcie_pme_suspend - Suspend PCIe PME service device.
396 * @srv: PCIe service device to suspend.
398 static int pcie_pme_suspend(struct pcie_device *srv)
400 struct pcie_pme_service_data *data = get_service_data(srv);
401 struct pci_dev *port = srv->port;
405 if (device_may_wakeup(&port->dev)) {
408 down_read(&pci_bus_sem);
409 wakeup = pcie_pme_check_wakeup(port->subordinate);
410 up_read(&pci_bus_sem);
412 spin_lock_irq(&data->lock);
414 ret = enable_irq_wake(srv->irq);
415 data->suspend_level = PME_SUSPEND_WAKEUP;
417 if (!wakeup || ret) {
418 struct pci_dev *port = srv->port;
420 pcie_pme_interrupt_enable(port, false);
421 pcie_clear_root_pme_status(port);
422 data->suspend_level = PME_SUSPEND_NOIRQ;
424 spin_unlock_irq(&data->lock);
426 synchronize_irq(srv->irq);
432 * pcie_pme_resume - Resume PCIe PME service device.
433 * @srv - PCIe service device to resume.
435 static int pcie_pme_resume(struct pcie_device *srv)
437 struct pcie_pme_service_data *data = get_service_data(srv);
439 spin_lock_irq(&data->lock);
440 if (data->suspend_level == PME_SUSPEND_NOIRQ) {
441 struct pci_dev *port = srv->port;
443 pcie_clear_root_pme_status(port);
444 pcie_pme_interrupt_enable(port, true);
446 disable_irq_wake(srv->irq);
448 data->suspend_level = PME_SUSPEND_NONE;
449 spin_unlock_irq(&data->lock);
455 * pcie_pme_remove - Prepare PCIe PME service device for removal.
456 * @srv - PCIe service device to remove.
458 static void pcie_pme_remove(struct pcie_device *srv)
460 pcie_pme_suspend(srv);
461 free_irq(srv->irq, srv);
462 kfree(get_service_data(srv));
465 static struct pcie_port_service_driver pcie_pme_driver = {
467 .port_type = PCI_EXP_TYPE_ROOT_PORT,
468 .service = PCIE_PORT_SERVICE_PME,
470 .probe = pcie_pme_probe,
471 .suspend = pcie_pme_suspend,
472 .resume = pcie_pme_resume,
473 .remove = pcie_pme_remove,
477 * pcie_pme_service_init - Register the PCIe PME service driver.
479 static int __init pcie_pme_service_init(void)
481 return pcie_port_service_register(&pcie_pme_driver);
484 module_init(pcie_pme_service_init);