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/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/pcieport_if.h>
21 #include <linux/pm_runtime.h>
27 * If this switch is set, MSI will not be used for PCIe PME signaling. This
28 * causes the PCIe port driver to use INTx interrupts only, but it turns out
29 * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
30 * wake-up from system sleep states.
32 bool pcie_pme_msi_disabled;
34 static int __init pcie_pme_setup(char *str)
36 if (!strncmp(str, "nomsi", 5))
37 pcie_pme_msi_disabled = true;
41 __setup("pcie_pme=", pcie_pme_setup);
43 enum pme_suspend_level {
49 struct pcie_pme_service_data {
51 struct pcie_device *srv;
52 struct work_struct work;
53 enum pme_suspend_level suspend_level;
57 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
58 * @dev: PCIe root port or event collector.
59 * @enable: Enable or disable the interrupt.
61 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
64 pcie_capability_set_word(dev, PCI_EXP_RTCTL,
67 pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
72 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
73 * @bus: PCI bus to scan.
75 * Scan given PCI bus and all buses under it for devices asserting PME#.
77 static bool pcie_pme_walk_bus(struct pci_bus *bus)
82 list_for_each_entry(dev, &bus->devices, bus_list) {
83 /* Skip PCIe devices in case we started from a root port. */
84 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
86 dev->pme_poll = false;
88 pci_wakeup_event(dev);
89 pm_request_resume(&dev->dev);
93 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
101 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
102 * @bus: Secondary bus of the bridge.
103 * @devfn: Device/function number to check.
105 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
106 * PCIe PME message. In such that case the bridge should use the Requester ID
107 * of device/function number 0 on its secondary bus.
109 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
117 dev = pci_dev_get(bus->self);
121 if (pci_is_pcie(dev) && pci_pcie_type(dev) == PCI_EXP_TYPE_PCI_BRIDGE) {
122 down_read(&pci_bus_sem);
123 if (pcie_pme_walk_bus(bus))
125 up_read(&pci_bus_sem);
133 * pcie_pme_handle_request - Find device that generated PME and handle it.
134 * @port: Root port or event collector that generated the PME interrupt.
135 * @req_id: PCIe Requester ID of the device that generated the PME.
137 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
139 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
144 /* First, check if the PME is from the root port itself. */
145 if (port->devfn == devfn && port->bus->number == busnr) {
147 port->pme_poll = false;
149 if (pci_check_pme_status(port)) {
150 pm_request_resume(&port->dev);
154 * Apparently, the root port generated the PME on behalf
155 * of a non-PCIe device downstream. If this is done by
156 * a root port, the Requester ID field in its status
157 * register may contain either the root port's, or the
158 * source device's information (PCI Express Base
159 * Specification, Rev. 2.0, Section 6.1.9).
161 down_read(&pci_bus_sem);
162 found = pcie_pme_walk_bus(port->subordinate);
163 up_read(&pci_bus_sem);
168 /* Second, find the bus the source device is on. */
169 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
173 /* Next, check if the PME is from a PCIe-PCI bridge. */
174 found = pcie_pme_from_pci_bridge(bus, devfn);
178 /* Finally, try to find the PME source on the bus. */
179 down_read(&pci_bus_sem);
180 list_for_each_entry(dev, &bus->devices, bus_list) {
182 if (dev->devfn == devfn) {
188 up_read(&pci_bus_sem);
191 /* The device is there, but we have to check its PME status. */
192 found = pci_check_pme_status(dev);
195 dev->pme_poll = false;
197 pci_wakeup_event(dev);
198 pm_request_resume(&dev->dev);
203 * The device is not there, but we can still try to recover by
204 * assuming that the PME was reported by a PCIe-PCI bridge that
205 * used devfn different from zero.
207 dev_dbg(&port->dev, "PME interrupt generated for non-existent device %02x:%02x.%d\n",
208 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
209 found = pcie_pme_from_pci_bridge(bus, 0);
214 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
218 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
219 * @work: Work structure giving access to service data.
221 static void pcie_pme_work_fn(struct work_struct *work)
223 struct pcie_pme_service_data *data =
224 container_of(work, struct pcie_pme_service_data, work);
225 struct pci_dev *port = data->srv->port;
228 spin_lock_irq(&data->lock);
231 if (data->suspend_level != PME_SUSPEND_NONE)
234 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
235 if (rtsta & PCI_EXP_RTSTA_PME) {
237 * Clear PME status of the port. If there are other
238 * pending PMEs, the status will be set again.
240 pcie_clear_root_pme_status(port);
242 spin_unlock_irq(&data->lock);
243 pcie_pme_handle_request(port, rtsta & 0xffff);
244 spin_lock_irq(&data->lock);
249 /* No need to loop if there are no more PMEs pending. */
250 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
253 spin_unlock_irq(&data->lock);
255 spin_lock_irq(&data->lock);
258 if (data->suspend_level == PME_SUSPEND_NONE)
259 pcie_pme_interrupt_enable(port, true);
261 spin_unlock_irq(&data->lock);
265 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
266 * @irq: Interrupt vector.
267 * @context: Interrupt context pointer.
269 static irqreturn_t pcie_pme_irq(int irq, void *context)
271 struct pci_dev *port;
272 struct pcie_pme_service_data *data;
276 port = ((struct pcie_device *)context)->port;
277 data = get_service_data((struct pcie_device *)context);
279 spin_lock_irqsave(&data->lock, flags);
280 pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
282 if (!(rtsta & PCI_EXP_RTSTA_PME)) {
283 spin_unlock_irqrestore(&data->lock, flags);
287 pcie_pme_interrupt_enable(port, false);
288 spin_unlock_irqrestore(&data->lock, flags);
290 /* We don't use pm_wq, because it's freezable. */
291 schedule_work(&data->work);
297 * pcie_pme_set_native - Set the PME interrupt flag for given device.
298 * @dev: PCI device to handle.
301 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
303 device_set_run_wake(&dev->dev, true);
304 dev->pme_interrupt = true;
309 * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
310 * @port: PCIe root port or event collector to handle.
312 * For each device below given root port, including the port itself (or for each
313 * root complex integrated endpoint if @port is a root complex event collector)
314 * set the flag indicating that it can signal run-time wake-up events via PCIe
317 static void pcie_pme_mark_devices(struct pci_dev *port)
319 pcie_pme_set_native(port, NULL);
320 if (port->subordinate)
321 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
325 * pcie_pme_probe - Initialize PCIe PME service for given root port.
326 * @srv: PCIe service to initialize.
328 static int pcie_pme_probe(struct pcie_device *srv)
330 struct pci_dev *port;
331 struct pcie_pme_service_data *data;
334 data = kzalloc(sizeof(*data), GFP_KERNEL);
338 spin_lock_init(&data->lock);
339 INIT_WORK(&data->work, pcie_pme_work_fn);
341 set_service_data(srv, data);
344 pcie_pme_interrupt_enable(port, false);
345 pcie_clear_root_pme_status(port);
347 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
353 dev_info(&port->dev, "Signaling PME with IRQ %d\n", srv->irq);
355 pcie_pme_mark_devices(port);
356 pcie_pme_interrupt_enable(port, true);
360 static bool pcie_pme_check_wakeup(struct pci_bus *bus)
367 list_for_each_entry(dev, &bus->devices, bus_list)
368 if (device_may_wakeup(&dev->dev)
369 || pcie_pme_check_wakeup(dev->subordinate))
376 * pcie_pme_suspend - Suspend PCIe PME service device.
377 * @srv: PCIe service device to suspend.
379 static int pcie_pme_suspend(struct pcie_device *srv)
381 struct pcie_pme_service_data *data = get_service_data(srv);
382 struct pci_dev *port = srv->port;
383 bool wakeup, wake_irq_enabled = false;
386 if (device_may_wakeup(&port->dev)) {
389 down_read(&pci_bus_sem);
390 wakeup = pcie_pme_check_wakeup(port->subordinate);
391 up_read(&pci_bus_sem);
393 spin_lock_irq(&data->lock);
395 ret = enable_irq_wake(srv->irq);
397 data->suspend_level = PME_SUSPEND_WAKEUP;
398 wake_irq_enabled = true;
401 if (!wake_irq_enabled) {
402 pcie_pme_interrupt_enable(port, false);
403 pcie_clear_root_pme_status(port);
404 data->suspend_level = PME_SUSPEND_NOIRQ;
406 spin_unlock_irq(&data->lock);
408 synchronize_irq(srv->irq);
414 * pcie_pme_resume - Resume PCIe PME service device.
415 * @srv - PCIe service device to resume.
417 static int pcie_pme_resume(struct pcie_device *srv)
419 struct pcie_pme_service_data *data = get_service_data(srv);
421 spin_lock_irq(&data->lock);
422 if (data->suspend_level == PME_SUSPEND_NOIRQ) {
423 struct pci_dev *port = srv->port;
425 pcie_clear_root_pme_status(port);
426 pcie_pme_interrupt_enable(port, true);
428 disable_irq_wake(srv->irq);
430 data->suspend_level = PME_SUSPEND_NONE;
431 spin_unlock_irq(&data->lock);
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,
447 * pcie_pme_service_init - Register the PCIe PME service driver.
449 static int __init pcie_pme_service_init(void)
451 return pcie_port_service_register(&pcie_pme_driver);
453 device_initcall(pcie_pme_service_init);