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/acpi.h>
23 #include <linux/pci-acpi.h>
24 #include <linux/pm_runtime.h>
30 * If this switch is set, MSI will not be used for PCIe PME signaling. This
31 * causes the PCIe port driver to use INTx interrupts only, but it turns out
32 * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based
33 * wake-up from system sleep states.
35 bool pcie_pme_msi_disabled;
37 static int __init pcie_pme_setup(char *str)
39 if (!strncmp(str, "nomsi", 5))
40 pcie_pme_msi_disabled = true;
44 __setup("pcie_pme=", pcie_pme_setup);
46 struct pcie_pme_service_data {
48 struct pcie_device *srv;
49 struct work_struct work;
50 bool noirq; /* Don't enable the PME interrupt used by this service. */
54 * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
55 * @dev: PCIe root port or event collector.
56 * @enable: Enable or disable the interrupt.
58 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
63 rtctl_pos = pci_pcie_cap(dev) + PCI_EXP_RTCTL;
65 pci_read_config_word(dev, rtctl_pos, &rtctl);
67 rtctl |= PCI_EXP_RTCTL_PMEIE;
69 rtctl &= ~PCI_EXP_RTCTL_PMEIE;
70 pci_write_config_word(dev, rtctl_pos, rtctl);
74 * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
75 * @bus: PCI bus to scan.
77 * Scan given PCI bus and all buses under it for devices asserting PME#.
79 static bool pcie_pme_walk_bus(struct pci_bus *bus)
84 list_for_each_entry(dev, &bus->devices, bus_list) {
85 /* Skip PCIe devices in case we started from a root port. */
86 if (!pci_is_pcie(dev) && pci_check_pme_status(dev)) {
87 pm_request_resume(&dev->dev);
88 pci_wakeup_event(dev);
92 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
100 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
101 * @bus: Secondary bus of the bridge.
102 * @devfn: Device/function number to check.
104 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
105 * PCIe PME message. In such that case the bridge should use the Requester ID
106 * of device/function number 0 on its secondary bus.
108 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
116 dev = pci_dev_get(bus->self);
120 if (pci_is_pcie(dev) && dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
121 down_read(&pci_bus_sem);
122 if (pcie_pme_walk_bus(bus))
124 up_read(&pci_bus_sem);
132 * pcie_pme_handle_request - Find device that generated PME and handle it.
133 * @port: Root port or event collector that generated the PME interrupt.
134 * @req_id: PCIe Requester ID of the device that generated the PME.
136 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
138 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
143 /* First, check if the PME is from the root port itself. */
144 if (port->devfn == devfn && port->bus->number == busnr) {
145 if (pci_check_pme_status(port)) {
146 pm_request_resume(&port->dev);
150 * Apparently, the root port generated the PME on behalf
151 * of a non-PCIe device downstream. If this is done by
152 * a root port, the Requester ID field in its status
153 * register may contain either the root port's, or the
154 * source device's information (PCI Express Base
155 * Specification, Rev. 2.0, Section 6.1.9).
157 down_read(&pci_bus_sem);
158 found = pcie_pme_walk_bus(port->subordinate);
159 up_read(&pci_bus_sem);
164 /* Second, find the bus the source device is on. */
165 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
169 /* Next, check if the PME is from a PCIe-PCI bridge. */
170 found = pcie_pme_from_pci_bridge(bus, devfn);
174 /* Finally, try to find the PME source on the bus. */
175 down_read(&pci_bus_sem);
176 list_for_each_entry(dev, &bus->devices, bus_list) {
178 if (dev->devfn == devfn) {
184 up_read(&pci_bus_sem);
187 /* The device is there, but we have to check its PME status. */
188 found = pci_check_pme_status(dev);
190 pm_request_resume(&dev->dev);
191 pci_wakeup_event(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 dev_dbg(&port->dev, "PME interrupt generated for "
201 "non-existent device %02x:%02x.%d\n",
202 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
203 found = pcie_pme_from_pci_bridge(bus, 0);
208 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
212 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
213 * @work: Work structure giving access to service data.
215 static void pcie_pme_work_fn(struct work_struct *work)
217 struct pcie_pme_service_data *data =
218 container_of(work, struct pcie_pme_service_data, work);
219 struct pci_dev *port = data->srv->port;
223 rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
225 spin_lock_irq(&data->lock);
231 pci_read_config_dword(port, rtsta_pos, &rtsta);
232 if (rtsta & PCI_EXP_RTSTA_PME) {
234 * Clear PME status of the port. If there are other
235 * pending PMEs, the status will be set again.
237 pcie_clear_root_pme_status(port);
239 spin_unlock_irq(&data->lock);
240 pcie_pme_handle_request(port, rtsta & 0xffff);
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;
274 port = ((struct pcie_device *)context)->port;
275 data = get_service_data((struct pcie_device *)context);
277 rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
279 spin_lock_irqsave(&data->lock, flags);
280 pci_read_config_dword(port, rtsta_pos, &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 dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
305 device_set_run_wake(&dev->dev, true);
306 dev->pme_interrupt = true;
311 * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
312 * @port: PCIe root port or event collector to handle.
314 * For each device below given root port, including the port itself (or for each
315 * root complex integrated endpoint if @port is a root complex event collector)
316 * set the flag indicating that it can signal run-time wake-up events via PCIe
319 static void pcie_pme_mark_devices(struct pci_dev *port)
321 pcie_pme_set_native(port, NULL);
322 if (port->subordinate) {
323 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
325 struct pci_bus *bus = port->bus;
328 /* Check if this is a root port event collector. */
329 if (port->pcie_type != PCI_EXP_TYPE_RC_EC || !bus)
332 down_read(&pci_bus_sem);
333 list_for_each_entry(dev, &bus->devices, bus_list)
335 && dev->pcie_type == PCI_EXP_TYPE_RC_END)
336 pcie_pme_set_native(dev, NULL);
337 up_read(&pci_bus_sem);
342 * pcie_pme_probe - Initialize PCIe PME service for given root port.
343 * @srv: PCIe service to initialize.
345 static int pcie_pme_probe(struct pcie_device *srv)
347 struct pci_dev *port;
348 struct pcie_pme_service_data *data;
351 data = kzalloc(sizeof(*data), GFP_KERNEL);
355 spin_lock_init(&data->lock);
356 INIT_WORK(&data->work, pcie_pme_work_fn);
358 set_service_data(srv, data);
361 pcie_pme_interrupt_enable(port, false);
362 pcie_clear_root_pme_status(port);
364 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
368 pcie_pme_mark_devices(port);
369 pcie_pme_interrupt_enable(port, true);
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;
384 spin_lock_irq(&data->lock);
385 pcie_pme_interrupt_enable(port, false);
386 pcie_clear_root_pme_status(port);
388 spin_unlock_irq(&data->lock);
390 synchronize_irq(srv->irq);
396 * pcie_pme_resume - Resume PCIe PME service device.
397 * @srv - PCIe service device to resume.
399 static int pcie_pme_resume(struct pcie_device *srv)
401 struct pcie_pme_service_data *data = get_service_data(srv);
402 struct pci_dev *port = srv->port;
404 spin_lock_irq(&data->lock);
406 pcie_clear_root_pme_status(port);
407 pcie_pme_interrupt_enable(port, true);
408 spin_unlock_irq(&data->lock);
414 * pcie_pme_remove - Prepare PCIe PME service device for removal.
415 * @srv - PCIe service device to resume.
417 static void pcie_pme_remove(struct pcie_device *srv)
419 pcie_pme_suspend(srv);
420 free_irq(srv->irq, srv);
421 kfree(get_service_data(srv));
424 static struct pcie_port_service_driver pcie_pme_driver = {
426 .port_type = PCI_EXP_TYPE_ROOT_PORT,
427 .service = PCIE_PORT_SERVICE_PME,
429 .probe = pcie_pme_probe,
430 .suspend = pcie_pme_suspend,
431 .resume = pcie_pme_resume,
432 .remove = pcie_pme_remove,
436 * pcie_pme_service_init - Register the PCIe PME service driver.
438 static int __init pcie_pme_service_init(void)
440 return pcie_port_service_register(&pcie_pme_driver);
443 module_init(pcie_pme_service_init);