--- /dev/null
+/*
+ * PCIe Native PME support
+ *
+ * Copyright (C) 2007 - 2009 Intel Corp
+ * Copyright (C) 2007 - 2009 Shaohua Li <shaohua.li@intel.com>
+ * Copyright (C) 2009 Rafael J. Wysocki <rjw@sisk.pl>, Novell Inc.
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License V2. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/device.h>
+#include <linux/pcieport_if.h>
+#include <linux/acpi.h>
+#include <linux/pci-acpi.h>
+#include <linux/pm_runtime.h>
+
+#include "../../pci.h"
+#include "pcie_pme.h"
+
+#define PCI_EXP_RTSTA_PME 0x10000 /* PME status */
+#define PCI_EXP_RTSTA_PENDING 0x20000 /* PME pending */
+
+/*
+ * If set, this switch will prevent the PCIe root port PME service driver from
+ * being registered. Consequently, the interrupt-based PCIe PME signaling will
+ * not be used by any PCIe root ports in that case.
+ */
+static bool pcie_pme_disabled;
+
+/*
+ * The PCI Express Base Specification 2.0, Section 6.1.8, states the following:
+ * "In order to maintain compatibility with non-PCI Express-aware system
+ * software, system power management logic must be configured by firmware to use
+ * the legacy mechanism of signaling PME by default. PCI Express-aware system
+ * software must notify the firmware prior to enabling native, interrupt-based
+ * PME signaling." However, if the platform doesn't provide us with a suitable
+ * notification mechanism or the notification fails, it is not clear whether or
+ * not we are supposed to use the interrupt-based PCIe PME signaling. The
+ * switch below can be used to indicate the desired behaviour. When set, it
+ * will make the kernel use the interrupt-based PCIe PME signaling regardless of
+ * the platform notification status, although the kernel will attempt to notify
+ * the platform anyway. When unset, it will prevent the kernel from using the
+ * the interrupt-based PCIe PME signaling if the platform notification fails,
+ * which is the default.
+ */
+static bool pcie_pme_force_enable;
+
+static int __init pcie_pme_setup(char *str)
+{
+ if (!strcmp(str, "off"))
+ pcie_pme_disabled = true;
+ else if (!strcmp(str, "force"))
+ pcie_pme_force_enable = true;
+ return 1;
+}
+__setup("pcie_pme=", pcie_pme_setup);
+
+/**
+ * pcie_pme_platform_setup - Ensure that the kernel controls the PCIe PME.
+ * @srv: PCIe PME root port service to use for carrying out the check.
+ *
+ * Notify the platform that the native PCIe PME is going to be used and return
+ * 'true' if the control of the PCIe PME registers has been acquired from the
+ * platform.
+ */
+static bool pcie_pme_platform_setup(struct pcie_device *srv)
+{
+ return !pcie_pme_platform_notify(srv) || pcie_pme_force_enable;
+}
+
+struct pcie_pme_service_data {
+ spinlock_t lock;
+ struct pcie_device *srv;
+ struct work_struct work;
+ bool noirq; /* Don't enable the PME interrupt used by this service. */
+};
+
+/**
+ * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation.
+ * @dev: PCIe root port or event collector.
+ * @enable: Enable or disable the interrupt.
+ */
+static void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
+{
+ int rtctl_pos;
+ u16 rtctl;
+
+ rtctl_pos = pci_find_capability(dev, PCI_CAP_ID_EXP) + PCI_EXP_RTCTL;
+
+ pci_read_config_word(dev, rtctl_pos, &rtctl);
+ if (enable)
+ rtctl |= PCI_EXP_RTCTL_PMEIE;
+ else
+ rtctl &= ~PCI_EXP_RTCTL_PMEIE;
+ pci_write_config_word(dev, rtctl_pos, rtctl);
+}
+
+/**
+ * pcie_pme_clear_status - Clear root port PME interrupt status.
+ * @dev: PCIe root port or event collector.
+ */
+static void pcie_pme_clear_status(struct pci_dev *dev)
+{
+ int rtsta_pos;
+ u32 rtsta;
+
+ rtsta_pos = pci_find_capability(dev, PCI_CAP_ID_EXP) + PCI_EXP_RTSTA;
+
+ pci_read_config_dword(dev, rtsta_pos, &rtsta);
+ rtsta |= PCI_EXP_RTSTA_PME;
+ pci_write_config_dword(dev, rtsta_pos, rtsta);
+}
+
+/**
+ * pcie_pme_walk_bus - Scan a PCI bus for devices asserting PME#.
+ * @bus: PCI bus to scan.
+ *
+ * Scan given PCI bus and all buses under it for devices asserting PME#.
+ */
+static bool pcie_pme_walk_bus(struct pci_bus *bus)
+{
+ struct pci_dev *dev;
+ bool ret = false;
+
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ /* Skip PCIe devices in case we started from a root port. */
+ if (!dev->is_pcie && pci_check_pme_status(dev)) {
+ pm_request_resume(&dev->dev);
+ ret = true;
+ }
+
+ if (dev->subordinate && pcie_pme_walk_bus(dev->subordinate))
+ ret = true;
+ }
+
+ return ret;
+}
+
+/**
+ * pcie_pme_from_pci_bridge - Check if PCIe-PCI bridge generated a PME.
+ * @bus: Secondary bus of the bridge.
+ * @devfn: Device/function number to check.
+ *
+ * PME from PCI devices under a PCIe-PCI bridge may be converted to an in-band
+ * PCIe PME message. In such that case the bridge should use the Requester ID
+ * of device/function number 0 on its secondary bus.
+ */
+static bool pcie_pme_from_pci_bridge(struct pci_bus *bus, u8 devfn)
+{
+ struct pci_dev *dev;
+ bool found = false;
+
+ if (devfn)
+ return false;
+
+ dev = pci_dev_get(bus->self);
+ if (!dev)
+ return false;
+
+ if (dev->is_pcie && dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+ down_read(&pci_bus_sem);
+ if (pcie_pme_walk_bus(bus))
+ found = true;
+ up_read(&pci_bus_sem);
+ }
+
+ pci_dev_put(dev);
+ return found;
+}
+
+/**
+ * pcie_pme_handle_request - Find device that generated PME and handle it.
+ * @port: Root port or event collector that generated the PME interrupt.
+ * @req_id: PCIe Requester ID of the device that generated the PME.
+ */
+static void pcie_pme_handle_request(struct pci_dev *port, u16 req_id)
+{
+ u8 busnr = req_id >> 8, devfn = req_id & 0xff;
+ struct pci_bus *bus;
+ struct pci_dev *dev;
+ bool found = false;
+
+ /* First, check if the PME is from the root port itself. */
+ if (port->devfn == devfn && port->bus->number == busnr) {
+ if (pci_check_pme_status(port)) {
+ pm_request_resume(&port->dev);
+ found = true;
+ } else {
+ /*
+ * Apparently, the root port generated the PME on behalf
+ * of a non-PCIe device downstream. If this is done by
+ * a root port, the Requester ID field in its status
+ * register may contain either the root port's, or the
+ * source device's information (PCI Express Base
+ * Specification, Rev. 2.0, Section 6.1.9).
+ */
+ down_read(&pci_bus_sem);
+ found = pcie_pme_walk_bus(port->subordinate);
+ up_read(&pci_bus_sem);
+ }
+ goto out;
+ }
+
+ /* Second, find the bus the source device is on. */
+ bus = pci_find_bus(pci_domain_nr(port->bus), busnr);
+ if (!bus)
+ goto out;
+
+ /* Next, check if the PME is from a PCIe-PCI bridge. */
+ found = pcie_pme_from_pci_bridge(bus, devfn);
+ if (found)
+ goto out;
+
+ /* Finally, try to find the PME source on the bus. */
+ down_read(&pci_bus_sem);
+ list_for_each_entry(dev, &bus->devices, bus_list) {
+ pci_dev_get(dev);
+ if (dev->devfn == devfn) {
+ found = true;
+ break;
+ }
+ pci_dev_put(dev);
+ }
+ up_read(&pci_bus_sem);
+
+ if (found) {
+ /* The device is there, but we have to check its PME status. */
+ found = pci_check_pme_status(dev);
+ if (found)
+ pm_request_resume(&dev->dev);
+ pci_dev_put(dev);
+ } else if (devfn) {
+ /*
+ * The device is not there, but we can still try to recover by
+ * assuming that the PME was reported by a PCIe-PCI bridge that
+ * used devfn different from zero.
+ */
+ dev_dbg(&port->dev, "PME interrupt generated for "
+ "non-existent device %02x:%02x.%d\n",
+ busnr, PCI_SLOT(devfn), PCI_FUNC(devfn));
+ found = pcie_pme_from_pci_bridge(bus, 0);
+ }
+
+ out:
+ if (!found)
+ dev_dbg(&port->dev, "Spurious native PME interrupt!\n");
+}
+
+/**
+ * pcie_pme_work_fn - Work handler for PCIe PME interrupt.
+ * @work: Work structure giving access to service data.
+ */
+static void pcie_pme_work_fn(struct work_struct *work)
+{
+ struct pcie_pme_service_data *data =
+ container_of(work, struct pcie_pme_service_data, work);
+ struct pci_dev *port = data->srv->port;
+ int rtsta_pos;
+ u32 rtsta;
+
+ rtsta_pos = pci_find_capability(port, PCI_CAP_ID_EXP) + PCI_EXP_RTSTA;
+
+ spin_lock_irq(&data->lock);
+
+ for (;;) {
+ if (data->noirq)
+ break;
+
+ pci_read_config_dword(port, rtsta_pos, &rtsta);
+ if (rtsta & PCI_EXP_RTSTA_PME) {
+ /*
+ * Clear PME status of the port. If there are other
+ * pending PMEs, the status will be set again.
+ */
+ pcie_pme_clear_status(port);
+
+ spin_unlock_irq(&data->lock);
+ pcie_pme_handle_request(port, rtsta & 0xffff);
+ spin_lock_irq(&data->lock);
+
+ continue;
+ }
+
+ /* No need to loop if there are no more PMEs pending. */
+ if (!(rtsta & PCI_EXP_RTSTA_PENDING))
+ break;
+
+ spin_unlock_irq(&data->lock);
+ cpu_relax();
+ spin_lock_irq(&data->lock);
+ }
+
+ if (!data->noirq)
+ pcie_pme_interrupt_enable(port, true);
+
+ spin_unlock_irq(&data->lock);
+}
+
+/**
+ * pcie_pme_irq - Interrupt handler for PCIe root port PME interrupt.
+ * @irq: Interrupt vector.
+ * @context: Interrupt context pointer.
+ */
+static irqreturn_t pcie_pme_irq(int irq, void *context)
+{
+ struct pci_dev *port;
+ struct pcie_pme_service_data *data;
+ int rtsta_pos;
+ u32 rtsta;
+ unsigned long flags;
+
+ port = ((struct pcie_device *)context)->port;
+ data = get_service_data((struct pcie_device *)context);
+
+ rtsta_pos = pci_find_capability(port, PCI_CAP_ID_EXP) + PCI_EXP_RTSTA;
+
+ spin_lock_irqsave(&data->lock, flags);
+ pci_read_config_dword(port, rtsta_pos, &rtsta);
+
+ if (!(rtsta & PCI_EXP_RTSTA_PME)) {
+ spin_unlock_irqrestore(&data->lock, flags);
+ return IRQ_NONE;
+ }
+
+ pcie_pme_interrupt_enable(port, false);
+ spin_unlock_irqrestore(&data->lock, flags);
+
+ /* We don't use pm_wq, because it's freezable. */
+ schedule_work(&data->work);
+
+ return IRQ_HANDLED;
+}
+
+/**
+ * pcie_pme_set_native - Set the PME interrupt flag for given device.
+ * @dev: PCI device to handle.
+ * @ign: Ignored.
+ */
+static int pcie_pme_set_native(struct pci_dev *dev, void *ign)
+{
+ dev_info(&dev->dev, "Signaling PME through PCIe PME interrupt\n");
+
+ device_set_run_wake(&dev->dev, true);
+ dev->pme_interrupt = true;
+ return 0;
+}
+
+/**
+ * pcie_pme_mark_devices - Set the PME interrupt flag for devices below a port.
+ * @port: PCIe root port or event collector to handle.
+ *
+ * For each device below given root port, including the port itself (or for each
+ * root complex integrated endpoint if @port is a root complex event collector)
+ * set the flag indicating that it can signal run-time wake-up events via PCIe
+ * PME interrupts.
+ */
+static void pcie_pme_mark_devices(struct pci_dev *port)
+{
+ pcie_pme_set_native(port, NULL);
+ if (port->subordinate) {
+ pci_walk_bus(port->subordinate, pcie_pme_set_native, NULL);
+ } else {
+ struct pci_bus *bus = port->bus;
+ struct pci_dev *dev;
+
+ /* Check if this is a root port event collector. */
+ if (port->pcie_type != PCI_EXP_TYPE_RC_EC || !bus)
+ return;
+
+ down_read(&pci_bus_sem);
+ list_for_each_entry(dev, &bus->devices, bus_list)
+ if (dev->is_pcie
+ && dev->pcie_type == PCI_EXP_TYPE_RC_END)
+ pcie_pme_set_native(dev, NULL);
+ up_read(&pci_bus_sem);
+ }
+}
+
+/**
+ * pcie_pme_probe - Initialize PCIe PME service for given root port.
+ * @srv: PCIe service to initialize.
+ */
+static int pcie_pme_probe(struct pcie_device *srv)
+{
+ struct pci_dev *port;
+ struct pcie_pme_service_data *data;
+ int ret;
+
+ if (!pcie_pme_platform_setup(srv))
+ return -EACCES;
+
+ data = kzalloc(sizeof(*data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ spin_lock_init(&data->lock);
+ INIT_WORK(&data->work, pcie_pme_work_fn);
+ data->srv = srv;
+ set_service_data(srv, data);
+
+ port = srv->port;
+ pcie_pme_interrupt_enable(port, false);
+ pcie_pme_clear_status(port);
+
+ ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv);
+ if (ret) {
+ kfree(data);
+ } else {
+ pcie_pme_mark_devices(port);
+ pcie_pme_interrupt_enable(port, true);
+ }
+
+ return ret;
+}
+
+/**
+ * pcie_pme_suspend - Suspend PCIe PME service device.
+ * @srv: PCIe service device to suspend.
+ */
+static int pcie_pme_suspend(struct pcie_device *srv)
+{
+ struct pcie_pme_service_data *data = get_service_data(srv);
+ struct pci_dev *port = srv->port;
+
+ spin_lock_irq(&data->lock);
+ pcie_pme_interrupt_enable(port, false);
+ pcie_pme_clear_status(port);
+ data->noirq = true;
+ spin_unlock_irq(&data->lock);
+
+ synchronize_irq(srv->irq);
+
+ return 0;
+}
+
+/**
+ * pcie_pme_resume - Resume PCIe PME service device.
+ * @srv - PCIe service device to resume.
+ */
+static int pcie_pme_resume(struct pcie_device *srv)
+{
+ struct pcie_pme_service_data *data = get_service_data(srv);
+ struct pci_dev *port = srv->port;
+
+ spin_lock_irq(&data->lock);
+ data->noirq = false;
+ pcie_pme_clear_status(port);
+ pcie_pme_interrupt_enable(port, true);
+ spin_unlock_irq(&data->lock);
+
+ return 0;
+}
+
+/**
+ * pcie_pme_remove - Prepare PCIe PME service device for removal.
+ * @srv - PCIe service device to resume.
+ */
+static void pcie_pme_remove(struct pcie_device *srv)
+{
+ pcie_pme_suspend(srv);
+ free_irq(srv->irq, srv);
+ kfree(get_service_data(srv));
+}
+
+static struct pcie_port_service_driver pcie_pme_driver = {
+ .name = "pcie_pme",
+ .port_type = PCI_EXP_TYPE_ROOT_PORT,
+ .service = PCIE_PORT_SERVICE_PME,
+
+ .probe = pcie_pme_probe,
+ .suspend = pcie_pme_suspend,
+ .resume = pcie_pme_resume,
+ .remove = pcie_pme_remove,
+};
+
+/**
+ * pcie_pme_service_init - Register the PCIe PME service driver.
+ */
+static int __init pcie_pme_service_init(void)
+{
+ return pcie_pme_disabled ?
+ -ENODEV : pcie_port_service_register(&pcie_pme_driver);
+}
+
+module_init(pcie_pme_service_init);
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