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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/pci/pcie/pme.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/pci/pcie/pme.c')
-rw-r--r-- | drivers/pci/pcie/pme.c | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/drivers/pci/pcie/pme.c b/drivers/pci/pcie/pme.c new file mode 100644 index 000000000..54d593d10 --- /dev/null +++ b/drivers/pci/pcie/pme.c @@ -0,0 +1,461 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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. + */ + +#include <linux/pci.h> +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/device.h> +#include <linux/pm_runtime.h> + +#include "../pci.h" +#include "portdrv.h" + +/* + * 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 (!strncmp(str, "nomsi", 5)) + pcie_pme_msi_disabled = true; + + return 1; +} +__setup("pcie_pme=", pcie_pme_setup); + +struct pcie_pme_service_data { + spinlock_t lock; + struct pcie_device *srv; + struct work_struct work; + bool noirq; /* If set, keep the PME interrupt disabled. */ +}; + +/** + * pcie_pme_interrupt_enable - Enable/disable PCIe PME interrupt generation. + * @dev: PCIe root port or event collector. + * @enable: Enable or disable the interrupt. + */ +void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable) +{ + if (enable) + pcie_capability_set_word(dev, PCI_EXP_RTCTL, + PCI_EXP_RTCTL_PMEIE); + else + pcie_capability_clear_word(dev, PCI_EXP_RTCTL, + PCI_EXP_RTCTL_PMEIE); +} + +/** + * 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)) { + if (dev->pme_poll) + dev->pme_poll = false; + + pci_wakeup_event(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) && pci_pcie_type(dev) == 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 (port->pme_poll) + port->pme_poll = false; + + 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) { + if (dev->pme_poll) + dev->pme_poll = false; + + pci_wakeup_event(dev); + 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. + */ + pci_dbg(port, "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) + pci_dbg(port, "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; + u32 rtsta; + + spin_lock_irq(&data->lock); + + for (;;) { + if (data->noirq) + break; + + pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta); + if (rtsta == (u32) ~0) + break; + + 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_clear_root_pme_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; + u32 rtsta; + unsigned long flags; + + port = ((struct pcie_device *)context)->port; + data = get_service_data((struct pcie_device *)context); + + spin_lock_irqsave(&data->lock, flags); + pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta); + + if (rtsta == (u32) ~0 || !(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_can_wakeup - Set the wakeup capability flag. + * @dev: PCI device to handle. + * @ign: Ignored. + */ +static int pcie_pme_can_wakeup(struct pci_dev *dev, void *ign) +{ + device_set_wakeup_capable(&dev->dev, true); + return 0; +} + +/** + * pcie_pme_mark_devices - Set the wakeup 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. + */ +static void pcie_pme_mark_devices(struct pci_dev *port) +{ + pcie_pme_can_wakeup(port, NULL); + if (port->subordinate) + pci_walk_bus(port->subordinate, pcie_pme_can_wakeup, NULL); +} + +/** + * 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; + + 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_clear_root_pme_status(port); + + ret = request_irq(srv->irq, pcie_pme_irq, IRQF_SHARED, "PCIe PME", srv); + if (ret) { + kfree(data); + return ret; + } + + pci_info(port, "Signaling PME with IRQ %d\n", srv->irq); + + pcie_pme_mark_devices(port); + pcie_pme_interrupt_enable(port, true); + return 0; +} + +static bool pcie_pme_check_wakeup(struct pci_bus *bus) +{ + struct pci_dev *dev; + + if (!bus) + return false; + + list_for_each_entry(dev, &bus->devices, bus_list) + if (device_may_wakeup(&dev->dev) + || pcie_pme_check_wakeup(dev->subordinate)) + return true; + + return false; +} + +static void pcie_pme_disable_interrupt(struct pci_dev *port, + struct pcie_pme_service_data *data) +{ + spin_lock_irq(&data->lock); + pcie_pme_interrupt_enable(port, false); + pcie_clear_root_pme_status(port); + data->noirq = true; + spin_unlock_irq(&data->lock); +} + +/** + * 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; + bool wakeup; + int ret; + + if (device_may_wakeup(&port->dev)) { + wakeup = true; + } else { + down_read(&pci_bus_sem); + wakeup = pcie_pme_check_wakeup(port->subordinate); + up_read(&pci_bus_sem); + } + if (wakeup) { + ret = enable_irq_wake(srv->irq); + if (!ret) + return 0; + } + + pcie_pme_disable_interrupt(port, data); + + 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); + + spin_lock_irq(&data->lock); + if (data->noirq) { + struct pci_dev *port = srv->port; + + pcie_clear_root_pme_status(port); + pcie_pme_interrupt_enable(port, true); + data->noirq = false; + } else { + disable_irq_wake(srv->irq); + } + spin_unlock_irq(&data->lock); + + return 0; +} + +/** + * pcie_pme_remove - Prepare PCIe PME service device for removal. + * @srv - PCIe service device to remove. + */ +static void pcie_pme_remove(struct pcie_device *srv) +{ + struct pcie_pme_service_data *data = get_service_data(srv); + + pcie_pme_disable_interrupt(srv->port, data); + free_irq(srv->irq, srv); + cancel_work_sync(&data->work); + kfree(data); +} + +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. + */ +int __init pcie_pme_init(void) +{ + return pcie_port_service_register(&pcie_pme_driver); +} |