linux-stable/drivers/pci/pcie/bw_notification.c
Linus Torvalds 414147d99b pci-v5.2-changes
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Merge tag 'pci-v5.2-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI updates from Bjorn Helgaas:
 "Enumeration changes:

   - Add _HPX Type 3 settings support, which gives firmware more
     influence over device configuration (Alexandru Gagniuc)

   - Support fixed bus numbers from bridge Enhanced Allocation
     capabilities (Subbaraya Sundeep)

   - Add "external-facing" DT property to identify cases where we
     require IOMMU protection against untrusted devices (Jean-Philippe
     Brucker)

   - Enable PCIe services for host controller drivers that use managed
     host bridge alloc (Jean-Philippe Brucker)

   - Log PCIe port service messages with pci_dev, not the pcie_device
     (Frederick Lawler)

   - Convert pciehp from pciehp_debug module parameter to generic
     dynamic debug (Frederick Lawler)

  Peer-to-peer DMA:

   - Add whitelist of Root Complexes that support peer-to-peer DMA
     between Root Ports (Christian König)

  Native controller drivers:

   - Add PCI host bridge DMA ranges for bridges that can't DMA
     everywhere, e.g., iProc (Srinath Mannam)

   - Add Amazon Annapurna Labs PCIe host controller driver (Jonathan
     Chocron)

   - Fix Tegra MSI target allocation so DMA doesn't generate unwanted
     MSIs (Vidya Sagar)

   - Fix of_node reference leaks (Wen Yang)

   - Fix Hyper-V module unload & device removal issues (Dexuan Cui)

   - Cleanup R-Car driver (Marek Vasut)

   - Cleanup Keystone driver (Kishon Vijay Abraham I)

   - Cleanup i.MX6 driver (Andrey Smirnov)

  Significant bug fixes:

   - Reset Lenovo ThinkPad P50 GPU so nouveau works after reboot (Lyude
     Paul)

   - Fix Switchtec firmware update performance issue (Wesley Sheng)

   - Work around Pericom switch link retraining erratum (Stefan Mätje)"

* tag 'pci-v5.2-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (141 commits)
  MAINTAINERS: Add Karthikeyan Mitran and Hou Zhiqiang for Mobiveil PCI
  PCI: pciehp: Remove pointless MY_NAME definition
  PCI: pciehp: Remove pointless PCIE_MODULE_NAME definition
  PCI: pciehp: Remove unused dbg/err/info/warn() wrappers
  PCI: pciehp: Log messages with pci_dev, not pcie_device
  PCI: pciehp: Replace pciehp_debug module param with dyndbg
  PCI: pciehp: Remove pciehp_debug uses
  PCI/AER: Log messages with pci_dev, not pcie_device
  PCI/DPC: Log messages with pci_dev, not pcie_device
  PCI/PME: Replace dev_printk(KERN_DEBUG) with dev_info()
  PCI/AER: Replace dev_printk(KERN_DEBUG) with dev_info()
  PCI: Replace dev_printk(KERN_DEBUG) with dev_info(), etc
  PCI: Replace printk(KERN_INFO) with pr_info(), etc
  PCI: Use dev_printk() when possible
  PCI: Cleanup setup-bus.c comments and whitespace
  PCI: imx6: Allow asynchronous probing
  PCI: dwc: Save root bus for driver remove hooks
  PCI: dwc: Use devm_pci_alloc_host_bridge() to simplify code
  PCI: dwc: Free MSI in dw_pcie_host_init() error path
  PCI: dwc: Free MSI IRQ page in dw_pcie_free_msi()
  ...
2019-05-14 10:30:10 -07:00

135 lines
3.7 KiB
C

// SPDX-License-Identifier: GPL-2.0+
/*
* PCI Express Link Bandwidth Notification services driver
* Author: Alexandru Gagniuc <mr.nuke.me@gmail.com>
*
* Copyright (C) 2019, Dell Inc
*
* The PCIe Link Bandwidth Notification provides a way to notify the
* operating system when the link width or data rate changes. This
* capability is required for all root ports and downstream ports
* supporting links wider than x1 and/or multiple link speeds.
*
* This service port driver hooks into the bandwidth notification interrupt
* and warns when links become degraded in operation.
*/
#include "../pci.h"
#include "portdrv.h"
static bool pcie_link_bandwidth_notification_supported(struct pci_dev *dev)
{
int ret;
u32 lnk_cap;
ret = pcie_capability_read_dword(dev, PCI_EXP_LNKCAP, &lnk_cap);
return (ret == PCIBIOS_SUCCESSFUL) && (lnk_cap & PCI_EXP_LNKCAP_LBNC);
}
static void pcie_enable_link_bandwidth_notification(struct pci_dev *dev)
{
u16 lnk_ctl;
pcie_capability_write_word(dev, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS);
pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnk_ctl);
lnk_ctl |= PCI_EXP_LNKCTL_LBMIE;
pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl);
}
static void pcie_disable_link_bandwidth_notification(struct pci_dev *dev)
{
u16 lnk_ctl;
pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnk_ctl);
lnk_ctl &= ~PCI_EXP_LNKCTL_LBMIE;
pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl);
}
static irqreturn_t pcie_bw_notification_irq(int irq, void *context)
{
struct pcie_device *srv = context;
struct pci_dev *port = srv->port;
u16 link_status, events;
int ret;
ret = pcie_capability_read_word(port, PCI_EXP_LNKSTA, &link_status);
events = link_status & PCI_EXP_LNKSTA_LBMS;
if (ret != PCIBIOS_SUCCESSFUL || !events)
return IRQ_NONE;
pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
pcie_update_link_speed(port->subordinate, link_status);
return IRQ_WAKE_THREAD;
}
static irqreturn_t pcie_bw_notification_handler(int irq, void *context)
{
struct pcie_device *srv = context;
struct pci_dev *port = srv->port;
struct pci_dev *dev;
/*
* Print status from downstream devices, not this root port or
* downstream switch port.
*/
down_read(&pci_bus_sem);
list_for_each_entry(dev, &port->subordinate->devices, bus_list)
pcie_report_downtraining(dev);
up_read(&pci_bus_sem);
return IRQ_HANDLED;
}
static int pcie_bandwidth_notification_probe(struct pcie_device *srv)
{
int ret;
/* Single-width or single-speed ports do not have to support this. */
if (!pcie_link_bandwidth_notification_supported(srv->port))
return -ENODEV;
ret = request_threaded_irq(srv->irq, pcie_bw_notification_irq,
pcie_bw_notification_handler,
IRQF_SHARED, "PCIe BW notif", srv);
if (ret)
return ret;
pcie_enable_link_bandwidth_notification(srv->port);
return 0;
}
static void pcie_bandwidth_notification_remove(struct pcie_device *srv)
{
pcie_disable_link_bandwidth_notification(srv->port);
free_irq(srv->irq, srv);
}
static int pcie_bandwidth_notification_suspend(struct pcie_device *srv)
{
pcie_disable_link_bandwidth_notification(srv->port);
return 0;
}
static int pcie_bandwidth_notification_resume(struct pcie_device *srv)
{
pcie_enable_link_bandwidth_notification(srv->port);
return 0;
}
static struct pcie_port_service_driver pcie_bandwidth_notification_driver = {
.name = "pcie_bw_notification",
.port_type = PCIE_ANY_PORT,
.service = PCIE_PORT_SERVICE_BWNOTIF,
.probe = pcie_bandwidth_notification_probe,
.suspend = pcie_bandwidth_notification_suspend,
.resume = pcie_bandwidth_notification_resume,
.remove = pcie_bandwidth_notification_remove,
};
int __init pcie_bandwidth_notification_init(void)
{
return pcie_port_service_register(&pcie_bandwidth_notification_driver);
}