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)) {
88 dev->pme_poll = false;
90 pci_wakeup_event(dev);
91 pm_request_resume(&dev->dev);
95 if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
103 * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
104 * @bus: Secondary bus of the bridge.
105 * @devfn: Device/function number to check.
107 * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
108 * PCIe PME message. In such that case the bridge should use the Requester ID
109 * of device/function number 0 on its secondary bus.
111 static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
119 dev = pci_dev_get(bus->self);
123 if (pci_is_pcie(dev) && dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
124 down_read(&pci_bus_sem);
125 if (pcie_pme_walk_bus(bus))
127 up_read(&pci_bus_sem);
135 * pcie_pme_handle_request - Find device that generated PME and handle it.
136 * @port: Root port or event collector that generated the PME interrupt.
137 * @req_id: PCIe Requester ID of the device that generated the PME.
139 static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
141 u8 busnr = req_id >> 8, devfn = req_id & 0xff;
146 /* First, check if the PME is from the root port itself. */
147 if (port->devfn == devfn && port->bus->number == busnr) {
149 port->pme_poll = false;
151 if (pci_check_pme_status(port)) {
152 pm_request_resume(&port->dev);
156 * Apparently, the root port generated the PME on behalf
157 * of a non-PCIe device downstream. If this is done by
158 * a root port, the Requester ID field in its status
159 * register may contain either the root port's, or the
160 * source device's information (PCI Express Base
161 * Specification, Rev. 2.0, Section 6.1.9).
163 down_read(&pci_bus_sem);
164 found = pcie_pme_walk_bus(port->subordinate);
165 up_read(&pci_bus_sem);
170 /* Second, find the bus the source device is on. */
171 bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
175 /* Next, check if the PME is from a PCIe-PCI bridge. */
176 found = pcie_pme_from_pci_bridge(bus, devfn);
180 /* Finally, try to find the PME source on the bus. */
181 down_read(&pci_bus_sem);
182 list_for_each_entry(dev, &bus->devices, bus_list) {
184 if (dev->devfn == devfn) {
190 up_read(&pci_bus_sem);
193 /* The device is there, but we have to check its PME status. */
194 found = pci_check_pme_status(dev);
197 dev->pme_poll = false;
199 pci_wakeup_event(dev);
200 pm_request_resume(&dev->dev);
205 * The device is not there, but we can still try to recover by
206 * assuming that the PME was reported by a PCIe-PCI bridge that
207 * used devfn different from zero.
209 dev_dbg(&port->dev, "PME interrupt generated for "
210 "non-existent device %02x:%02x.%d\n",
211 busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
212 found = pcie_pme_from_pci_bridge(bus, 0);
217 dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
221 * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
222 * @work: Work structure giving access to service data.
224 static void pcie_pme_work_fn(struct work_struct *work)
226 struct pcie_pme_service_data *data =
227 container_of(work, struct pcie_pme_service_data, work);
228 struct pci_dev *port = data->srv->port;
232 rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
234 spin_lock_irq(&data->lock);
240 pci_read_config_dword(port, rtsta_pos, &rtsta);
241 if (rtsta & PCI_EXP_RTSTA_PME) {
243 * Clear PME status of the port. If there are other
244 * pending PMEs, the status will be set again.
246 pcie_clear_root_pme_status(port);
248 spin_unlock_irq(&data->lock);
249 pcie_pme_handle_request(port, rtsta & 0xffff);
250 spin_lock_irq(&data->lock);
255 /* No need to loop if there are no more PMEs pending. */
256 if (!(rtsta & PCI_EXP_RTSTA_PENDING))
259 spin_unlock_irq(&data->lock);
261 spin_lock_irq(&data->lock);
265 pcie_pme_interrupt_enable(port, true);
267 spin_unlock_irq(&data->lock);
271 * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
272 * @irq: Interrupt vector.
273 * @context: Interrupt context pointer.
275 static irqreturn_t pcie_pme_irq(int irq, void *context)
277 struct pci_dev *port;
278 struct pcie_pme_service_data *data;
283 port = ((struct pcie_device *)context)->port;
284 data = get_service_data((struct pcie_device *)context);
286 rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
288 spin_lock_irqsave(&data->lock, flags);
289 pci_read_config_dword(port, rtsta_pos, &rtsta);
291 if (!(rtsta & PCI_EXP_RTSTA_PME)) {
292 spin_unlock_irqrestore(&data->lock, flags);
296 pcie_pme_interrupt_enable(port, false);
297 spin_unlock_irqrestore(&data->lock, flags);
299 /* We don't use pm_wq, because it's freezable. */
300 schedule_work(&data->work);
306 * pcie_pme_set_native - Set the PME interrupt flag for given device.
307 * @dev: PCI device to handle.
310 static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
312 dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
314 device_set_run_wake(&dev->dev, true);
315 dev->pme_interrupt = true;
320 * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
321 * @port: PCIe root port or event collector to handle.
323 * For each device below given root port, including the port itself (or for each
324 * root complex integrated endpoint if @port is a root complex event collector)
325 * set the flag indicating that it can signal run-time wake-up events via PCIe
328 static void pcie_pme_mark_devices(struct pci_dev *port)
330 pcie_pme_set_native(port, NULL);
331 if (port->subordinate) {
332 pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
334 struct pci_bus *bus = port->bus;
337 /* Check if this is a root port event collector. */
338 if (port->pcie_type != PCI_EXP_TYPE_RC_EC || !bus)
341 down_read(&pci_bus_sem);
342 list_for_each_entry(dev, &bus->devices, bus_list)
344 && dev->pcie_type == PCI_EXP_TYPE_RC_END)
345 pcie_pme_set_native(dev, NULL);
346 up_read(&pci_bus_sem);
351 * pcie_pme_probe - Initialize PCIe PME service for given root port.
352 * @srv: PCIe service to initialize.
354 static int pcie_pme_probe(struct pcie_device *srv)
356 struct pci_dev *port;
357 struct pcie_pme_service_data *data;
360 data = kzalloc(sizeof(*data), GFP_KERNEL);
364 spin_lock_init(&data->lock);
365 INIT_WORK(&data->work, pcie_pme_work_fn);
367 set_service_data(srv, data);
370 pcie_pme_interrupt_enable(port, false);
371 pcie_clear_root_pme_status(port);
373 ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
377 pcie_pme_mark_devices(port);
378 pcie_pme_interrupt_enable(port, true);
385 * pcie_pme_suspend - Suspend PCIe PME service device.
386 * @srv: PCIe service device to suspend.
388 static int pcie_pme_suspend(struct pcie_device *srv)
390 struct pcie_pme_service_data *data = get_service_data(srv);
391 struct pci_dev *port = srv->port;
393 spin_lock_irq(&data->lock);
394 pcie_pme_interrupt_enable(port, false);
395 pcie_clear_root_pme_status(port);
397 spin_unlock_irq(&data->lock);
399 synchronize_irq(srv->irq);
405 * pcie_pme_resume - Resume PCIe PME service device.
406 * @srv - PCIe service device to resume.
408 static int pcie_pme_resume(struct pcie_device *srv)
410 struct pcie_pme_service_data *data = get_service_data(srv);
411 struct pci_dev *port = srv->port;
413 spin_lock_irq(&data->lock);
415 pcie_clear_root_pme_status(port);
416 pcie_pme_interrupt_enable(port, true);
417 spin_unlock_irq(&data->lock);
423 * pcie_pme_remove - Prepare PCIe PME service device for removal.
424 * @srv - PCIe service device to resume.
426 static void pcie_pme_remove(struct pcie_device *srv)
428 pcie_pme_suspend(srv);
429 free_irq(srv->irq, srv);
430 kfree(get_service_data(srv));
433 static struct pcie_port_service_driver pcie_pme_driver = {
435 .port_type = PCI_EXP_TYPE_ROOT_PORT,
436 .service = PCIE_PORT_SERVICE_PME,
438 .probe = pcie_pme_probe,
439 .suspend = pcie_pme_suspend,
440 .resume = pcie_pme_resume,
441 .remove = pcie_pme_remove,
445 * pcie_pme_service_init - Register the PCIe PME service driver.
447 static int __init pcie_pme_service_init(void)
449 return pcie_port_service_register(&pcie_pme_driver);
452 module_init(pcie_pme_service_init);