From eb34da60edee8cf7bac691a406a1ddaa4175e5bc Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 27 Sep 2018 16:38:19 -0500 Subject: [PATCH] PCI: pciehp: Disable hotplug interrupt during suspend When PCIe hotplug port is transitioned into D3hot, the link to the downstream component will go down. If hotplug interrupt generation is enabled when that happens, it will trigger immediately, waking up the system and bringing the link back up. To prevent this, disable hotplug interrupt generation when system suspend is entered. This does not prevent wakeup from low power states according to PCIe 4.0 spec section 6.7.3.4: Software enables a hot-plug event to generate a wakeup event by enabling software notification of the event as described in Section 6.7.3.1. Note that in order for software to disable interrupt generation while keeping wakeup generation enabled, the Hot-Plug Interrupt Enable bit must be cleared. So as long as we have set the slot event mask accordingly, wakeup should work even if slot interrupt is disabled. The port should trigger wake and then send PME to the root port when the PCIe hierarchy is brought back up. Limit this to systems using native PME mechanism to make sure older Apple systems depending on commit e3354628c376 ("PCI: pciehp: Support interrupts sent from D3hot") still continue working. Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas Reviewed-by: Rafael J. Wysocki --- drivers/pci/hotplug/pciehp.h | 2 ++ drivers/pci/hotplug/pciehp_core.c | 18 ++++++++++++++++++ drivers/pci/hotplug/pciehp_hpc.c | 10 ++++++++++ 3 files changed, 30 insertions(+) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 75fd525..506e1d9 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -176,6 +176,8 @@ struct controller *pcie_init(struct pcie_device *dev); int pcie_init_notification(struct controller *ctrl); void pcie_shutdown_notification(struct controller *ctrl); void pcie_clear_hotplug_events(struct controller *ctrl); +void pcie_enable_interrupt(struct controller *ctrl); +void pcie_disable_interrupt(struct controller *ctrl); int pciehp_power_on_slot(struct controller *ctrl); void pciehp_power_off_slot(struct controller *ctrl); void pciehp_get_power_status(struct controller *ctrl, u8 *status); diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c index 9440479..df5ae02 100644 --- a/drivers/pci/hotplug/pciehp_core.c +++ b/drivers/pci/hotplug/pciehp_core.c @@ -242,8 +242,23 @@ static void pciehp_remove(struct pcie_device *dev) } #ifdef CONFIG_PM +static bool pme_is_native(struct pcie_device *dev) +{ + const struct pci_host_bridge *host; + + host = pci_find_host_bridge(dev->port->bus); + return pcie_ports_native || host->native_pme; +} + static int pciehp_suspend(struct pcie_device *dev) { + /* + * Disable hotplug interrupt so that it does not trigger + * immediately when the downstream link goes down. + */ + if (pme_is_native(dev)) + pcie_disable_interrupt(get_service_data(dev)); + return 0; } @@ -266,6 +281,9 @@ static int pciehp_resume(struct pcie_device *dev) { struct controller *ctrl = get_service_data(dev); + if (pme_is_native(dev)) + pcie_enable_interrupt(ctrl); + pciehp_check_presence(ctrl); return 0; diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index f0f3f4a..46598b4 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -732,6 +732,16 @@ void pcie_clear_hotplug_events(struct controller *ctrl) PCI_EXP_SLTSTA_PDC | PCI_EXP_SLTSTA_DLLSC); } +void pcie_enable_interrupt(struct controller *ctrl) +{ + pcie_write_cmd(ctrl, PCI_EXP_SLTCTL_HPIE, PCI_EXP_SLTCTL_HPIE); +} + +void pcie_disable_interrupt(struct controller *ctrl) +{ + pcie_write_cmd(ctrl, 0, PCI_EXP_SLTCTL_HPIE); +} + /* * pciehp has a 1:1 bus:slot relationship so we ultimately want a secondary * bus reset of the bridge, but at the same time we want to ensure that it is -- 2.7.4