Merge tag 'pci-v5.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

Pull PCI updates from Bjorn Helgaas:

 - Use match_string() instead of reimplementing it (Andy Shevchenko)

 - Enable SERR# forwarding for all bridges (Bharat Kumar Gogada)

 - Use Latency Tolerance Reporting if already enabled by platform (Bjorn
   Helgaas)

 - Save/restore LTR info for suspend/resume (Bjorn Helgaas)

 - Fix DPC use of uninitialized data (Dongdong Liu)

 - Probe bridge window attributes only once at enumeration-time to fix
   device accesses during rescan (Bjorn Helgaas)

 - Return BAR size (not "size -1 ") from pci_size() to simplify code (Du
   Changbin)

 - Use config header type (not class code) identify bridges more
   reliably (Honghui Zhang)

 - Work around Intel Denverton incorrect Trace Hub BAR size reporting
   (Alexander Shishkin)

 - Reorder pciehp cached state/hardware state updates to avoid missed
   interrupts (Mika Westerberg)

 - Turn ibmphp semaphores into completions or mutexes (Arnd Bergmann)

 - Mark expected switch fall-through (Mathieu Malaterre)

 - Use of_node_name_eq() for node name comparisons (Rob Herring)

 - Add ACS and pciehp quirks for HXT SD4800 (Shunyong Yang)

 - Consolidate Rohm Vendor ID definitions (Andy Shevchenko)

 - Use u32 (not __u32) for things not exposed to userspace (Logan
   Gunthorpe)

 - Fix locking semantics of bus and slot reset interfaces (Alex
   Williamson)

 - Update PCIEPORTBUS Kconfig help text (Hou Zhiqiang)

 - Allow portdrv to claim subtractive decode Ports so PCIe services will
   work for them (Honghui Zhang)

 - Report PCIe links that become degraded at run-time (Alexandru
   Gagniuc)

 - Blacklist Gigabyte X299 Root Port power management to fix Thunderbolt
   hotplug (Mika Westerberg)

 - Revert runtime PM suspend/resume callbacks that broke PME on network
   cable plug (Mika Westerberg)

 - Disable Data Link State Changed interrupts to prevent wakeup
   immediately after suspend (Mika Westerberg)

 - Extend altera to support Stratix 10 (Ley Foon Tan)

 - Allow building altera driver on ARM64 (Ley Foon Tan)

 - Replace Douglas with Tom Joseph as Cadence PCI host/endpoint
   maintainer (Lorenzo Pieralisi)

 - Add DT support for R-Car RZ/G2E (R8A774C0) (Fabrizio Castro)

 - Add dra72x/dra74x/dra76x SoC compatible strings (Kishon Vijay Abraham I)

 - Enable x2 mode support for dra72x/dra74x/dra76x SoC (Kishon Vijay
   Abraham I)

 - Configure dra7xx PHY to PCIe mode (Kishon Vijay Abraham I)

 - Simplify dwc (remove unnecessary header includes, name variables
   consistently, reduce inverted logic, etc) (Gustavo Pimentel)

 - Add i.MX8MQ support (Andrey Smirnov)

 - Add message to help debug dwc MSI-X mask bit errors (Gustavo
   Pimentel)

 - Work around imx7d PCIe PLL erratum (Trent Piepho)

 - Don't assert qcom reset GPIO during probe (Bjorn Andersson)

 - Skip dwc MSI init if MSIs have been disabled (Lucas Stach)

 - Use memcpy_fromio()/memcpy_toio() instead of plain memcpy() in PCI
   endpoint framework (Wen Yang)

 - Add interface to discover supported endpoint features to replace a
   bitfield that wasn't flexible enough (Kishon Vijay Abraham I)

 - Implement the new supported-feature interface for designware-plat,
   dra7xx, rockchip, cadence (Kishon Vijay Abraham I)

 - Fix issues with 64-bit BAR in endpoints (Kishon Vijay Abraham I)

 - Add layerscape endpoint mode support (Xiaowei Bao)

 - Remove duplicate struct hv_vp_set in favor of struct hv_vpset (Maya
   Nakamura)

 - Rework hv_irq_unmask() to use cpumask_to_vpset() instead of
   open-coded reimplementation (Maya Nakamura)

 - Align Hyper-V struct retarget_msi_interrupt arguments (Maya Nakamura)

 - Fix mediatek MMIO size computation to enable full size of available
   MMIO space (Honghui Zhang)

 - Fix mediatek DMA window size computation to allow endpoint DMA access
   to full DRAM address range (Honghui Zhang)

 - Fix mvebu prefetchable BAR regression caused by common bridge
   emulation that assumed all bridges had prefetchable windows (Thomas
   Petazzoni)

 - Make advk_pci_bridge_emul_ops static (Wei Yongjun)

 - Configure MPS settings for VMD root ports (Jon Derrick)

* tag 'pci-v5.1-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (92 commits)
  PCI: Update PCIEPORTBUS Kconfig help text
  PCI: Fix "try" semantics of bus and slot reset
  PCI/LINK: Report degraded links via link bandwidth notification
  dt-bindings: PCI: altera: Add altr,pcie-root-port-2.0
  PCI: altera: Enable driver on ARM64
  PCI: altera: Add Stratix 10 PCIe support
  PCI/PME: Fix possible use-after-free on remove
  PCI: aardvark: Make symbol 'advk_pci_bridge_emul_ops' static
  PCI: dwc: skip MSI init if MSIs have been explicitly disabled
  PCI: hv: Refactor hv_irq_unmask() to use cpumask_to_vpset()
  PCI: hv: Replace hv_vp_set with hv_vpset
  PCI: hv: Add __aligned(8) to struct retarget_msi_interrupt
  PCI: mediatek: Enlarge PCIe2AHB window size to support 4GB DRAM
  PCI: mediatek: Fix memory mapped IO range size computation
  PCI: dwc: Remove superfluous shifting in definitions
  PCI: dwc: Make use of GENMASK/FIELD_PREP
  PCI: dwc: Make use of BIT() in constant definitions
  PCI: dwc: Share code for dw_pcie_rd/wr_other_conf()
  PCI: dwc: Make use of IS_ALIGNED()
  PCI: imx6: Add code to request/control "pcie_aux" clock for i.MX8MQ
  ...

1 files changed, 110 insertions, 0 deletions

diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c
new file mode 100644
index 000000000000..d2eae3b7cc0f
--- /dev/null
+++ b/drivers/pci/pcie/bw_notification.c
@@ -0,0 +1,110 @@
+// 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_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_handler(int irq, void *context)
+{
+	struct pcie_device *srv = context;
+	struct pci_dev *port = srv->port;
+	struct pci_dev *dev;
+	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;
+
+	/*
+	 * 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_print_link_status(dev, false);
+	up_read(&pci_bus_sem);
+
+	pcie_update_link_speed(port->subordinate, link_status);
+	pcie_capability_write_word(port, PCI_EXP_LNKSTA, events);
+	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, NULL, 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 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,
+	.remove		= pcie_bandwidth_notification_remove,
+};
+
+int __init pcie_bandwidth_notification_init(void)
+{
+	return pcie_port_service_register(&pcie_bandwidth_notification_driver);
+}