diff options
Diffstat (limited to 'drivers/pci/pcie/pme/pcie_pme.c')
| -rw-r--r-- | drivers/pci/pcie/pme/pcie_pme.c | 505 |
1 files changed, 505 insertions, 0 deletions
diff --git a/drivers/pci/pcie/pme/pcie_pme.c b/drivers/pci/pcie/pme/pcie_pme.c new file mode 100644 index 000000000000..7b3cbff547ee --- /dev/null +++ b/drivers/pci/pcie/pme/pcie_pme.c @@ -0,0 +1,505 @@ +/* + * 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; + +/* + * If this switch is set, MSI will not be used for PCIe PME signaling. This + * causes the PCIe port driver to use INTx interrupts only, but it turns out + * that using MSI for PCIe PME signaling doesn't play well with PCIe PME-based + * wake-up from system sleep states. + */ +bool pcie_pme_msi_disabled; + +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; + else if (!strcmp(str, "nomsi")) + pcie_pme_msi_disabled = 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) +{ + if (!pcie_pme_platform_notify(srv)) + return true; + return 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_pcie_cap(dev) + 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_pcie_cap(dev) + 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 (!pci_is_pcie(dev) && 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 (pci_is_pcie(dev) && 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_pcie_cap(port) + 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_pcie_cap(port) + 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 (pci_is_pcie(dev) + && 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); |