kernel/linux.git/drivers/pci/hotplug/pciehp_ctrl.c, branch v6.12.80

PCI: pciehp: Cancel bringup sequence if card is not present

2023-05-24T16:52:38+00:00

If a PCIe hotplug slot has an Attention Button, the normal hot-add flow is: - Slot is empty and slot power is off - User inserts card in slot and presses Attention Button - OS blinks Power Indicator for 5 seconds - After 5 seconds, OS turns on Power Indicator, turns on slot power, and enumerates the device Previously, if a user pressed the Attention Button on an *empty* slot, pciehp logged the following messages and blinked the Power Indicator until a second button press: [0.000] pciehp: Button press: will power on in 5 sec [0.001] # Power Indicator starts blinking [5.001] # 5 second timeout; slot is empty, so we should cancel the request to power on and turn off Power Indicator [7.000] # Power Indicator still blinking [8.000] # possible card insertion [9.000] pciehp: Button press: canceling request to power on The first button press incorrectly left the slot in BLINKINGON_STATE, so the second was interpreted as a "cancel power on" event regardless of whether a card was present. If the slot is empty, turn off the Power Indicator and return from BLINKINGON_STATE to OFF_STATE after 5 seconds, effectively canceling the request to power on. Putting the slot in OFF_STATE also means the second button press will correctly request a slot power on if the slot is occupied. [bhelgaas: commit log] Link: https://lore.kernel.org/r/20230512021518.336460-1-clementwei90@163.com Fixes: d331710ea78f ("PCI: pciehp: Become resilient to missed events") Suggested-by: Lukas Wunner Signed-off-by: Rongguang Wei Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner

PCI: pciehp: Simplify Attention Button logging

2023-05-24T16:49:50+00:00

Previously, pressing the Attention Button always logged two lines, the first from pciehp_ist() and the second from pciehp_handle_button_press(): Attention button pressed Powering on due to button press Since pciehp_handle_button_press() always logs the more detailed message, remove the generic "Attention button pressed" message. Reword the pciehp_handle_button_press() to be of the form: Button press: will power on in 5 sec Button press: will power off in 5 sec Button press: canceling request to power on Button press: canceling request to power off Button press: ignoring invalid state %#x Link: https://lore.kernel.org/r/20230522214051.619337-1-helgaas@kernel.org Signed-off-by: Bjorn Helgaas Reviewed-by: Lukas Wunner

Merge tag 'pci-v5.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci

2020-10-22T19:41:00+00:00

Pull PCI updates from Bjorn Helgaas: "Enumeration: - Print IRQ number used by PCIe Link Bandwidth Notification (Dongdong Liu) - Add schedule point in pci_read_config() to reduce max latency (Jiang Biao) - Add Kconfig options for MPS/MRRS strategy (Jim Quinlan) Resource management: - Fix pci_iounmap() memory leak when !CONFIG_GENERIC_IOMAP (Lorenzo Pieralisi) PCIe native device hotplug: - Reduce noisiness on hot removal (Lukas Wunner) Power management: - Revert "PCI/PM: Apply D2 delay as milliseconds, not microseconds" that was done on the basis of spec typo (Bjorn Helgaas) - Rename pci_dev.d3_delay to d3hot_delay to remove D3hot/D3cold ambiguity (Krzysztof Wilczyński) - Remove unused pcibios_pm_ops (Vaibhav Gupta) IOMMU: - Enable Translation Blocking for external devices to harden against DMA attacks (Rajat Jain) Error handling: - Add an ACPI APEI notifier chain for vendor CPER records to enable device-specific error handling (Shiju Jose) ASPM: - Remove struct aspm_register_info to simplify code (Saheed O. Bolarinwa) Amlogic Meson PCIe controller driver: - Build as module by default (Kevin Hilman) Ampere Altra PCIe controller driver: - Add MCFG quirk to work around non-standard ECAM implementation (Tuan Phan) Broadcom iProc PCIe controller driver: - Set affinity mask on MSI interrupts (Mark Tomlinson) Broadcom STB PCIe controller driver: - Make PCIE_BRCMSTB depend on ARCH_BRCMSTB (Jim Quinlan) - Add DT bindings for more Brcmstb chips (Jim Quinlan) - Add bcm7278 register info (Jim Quinlan) - Add bcm7278 PERST# support (Jim Quinlan) - Add suspend and resume pm_ops (Jim Quinlan) - Add control of rescal reset (Jim Quinlan) - Set additional internal memory DMA viewport sizes (Jim Quinlan) - Accommodate MSI for older chips (Jim Quinlan) - Set bus max burst size by chip type (Jim Quinlan) - Add support for bcm7211, bcm7216, bcm7445, bcm7278 (Jim Quinlan) Freescale i.MX6 PCIe controller driver: - Use dev_err_probe() to reduce redundant messages (Anson Huang) Freescale Layerscape PCIe controller driver: - Enforce 4K DMA buffer alignment in endpoint test (Hou Zhiqiang) - Add DT compatible strings for ls1088a, ls2088a (Xiaowei Bao) - Add endpoint support for ls1088a, ls2088a (Xiaowei Bao) - Add endpoint test support for lS1088a (Xiaowei Bao) - Add MSI-X support for ls1088a (Xiaowei Bao) HiSilicon HIP PCIe controller driver: - Handle HIP-specific errors via ACPI APEI (Yicong Yang) HiSilicon Kirin PCIe controller driver: - Return -EPROBE_DEFER if the GPIO isn't ready (Bean Huo) Intel VMD host bridge driver: - Factor out physical offset, bus offset, IRQ domain, IRQ allocation (Jon Derrick) - Use generic PCI PM correctly (Jon Derrick) Marvell Aardvark PCIe controller driver: - Fix compilation on s390 (Pali Rohár) - Implement driver 'remove' function and allow to build it as module (Pali Rohár) - Move PCIe reset card code to advk_pcie_train_link() (Pali Rohár) - Convert mvebu a3700 internal SMCC firmware return codes to errno (Pali Rohár) - Fix initialization with old Marvell's Arm Trusted Firmware (Pali Rohár) Microsoft Hyper-V host bridge driver: - Fix hibernation in case interrupts are not re-created (Dexuan Cui) NVIDIA Tegra PCIe controller driver: - Stop checking return value of debugfs_create() functions (Greg Kroah-Hartman) - Convert to use DEFINE_SEQ_ATTRIBUTE macro (Liu Shixin) Qualcomm PCIe controller driver: - Reset PCIe to work around Qsdk U-Boot issue (Ansuel Smith) Renesas R-Car PCIe controller driver: - Add DT documentation for r8a774a1, r8a774b1, r8a774e1 endpoints (Lad Prabhakar) - Add RZ/G2M, RZ/G2N, RZ/G2H IDs to endpoint test (Lad Prabhakar) - Add DT support for r8a7742 (Lad Prabhakar) Socionext UniPhier Pro5 controller driver: - Add DT descriptions of iATU register (host and endpoint) (Kunihiko Hayashi) Synopsys DesignWare PCIe controller driver: - Add link up check in dw_child_pcie_ops.map_bus() (racy, but seems unavoidable) (Hou Zhiqiang) - Fix endpoint Header Type check so multi-function devices work (Hou Zhiqiang) - Skip PCIE_MSI_INTR0* programming if MSI is disabled (Jisheng Zhang) - Stop leaking MSI page in suspend/resume (Jisheng Zhang) - Add common iATU register support instead of keystone-specific code (Kunihiko Hayashi) - Major config space access and other cleanups in dwc core and drivers that use it (al, exynos, histb, imx6, intel-gw, keystone, kirin, meson, qcom, tegra) (Rob Herring) - Add multiple PFs support for endpoint (Xiaowei Bao) - Add MSI-X doorbell mode in endpoint mode (Xiaowei Bao) Miscellaneous: - Use fallthrough pseudo-keyword (Gustavo A. R. Silva) - Fix "0 used as NULL pointer" warnings (Gustavo Pimentel) - Fix "cast truncates bits from constant value" warnings (Gustavo Pimentel) - Remove redundant zeroing for sg_init_table() (Julia Lawall) - Use scnprintf(), not snprintf(), in sysfs "show" functions (Krzysztof Wilczyński) - Remove unused assignments (Krzysztof Wilczyński) - Fix "0 used as NULL pointer" warning (Krzysztof Wilczyński) - Simplify bool comparisons (Krzysztof Wilczyński) - Use for_each_child_of_node() and for_each_node_by_name() (Qinglang Miao) - Simplify return expressions (Qinglang Miao)" * tag 'pci-v5.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (147 commits) PCI: vmd: Update VMD PM to correctly use generic PCI PM PCI: vmd: Create IRQ allocation helper PCI: vmd: Create IRQ Domain configuration helper PCI: vmd: Create bus offset configuration helper PCI: vmd: Create physical offset helper PCI: v3-semi: Remove unneeded break PCI: dwc: Add link up check in dw_child_pcie_ops.map_bus() PCI/ASPM: Remove struct pcie_link_state.l1ss PCI/ASPM: Remove struct aspm_register_info.l1ss_cap PCI/ASPM: Pass L1SS Capabilities value, not struct aspm_register_info PCI/ASPM: Remove struct aspm_register_info.l1ss_ctl1 PCI/ASPM: Remove struct aspm_register_info.l1ss_ctl2 (unused) PCI/ASPM: Remove struct aspm_register_info.l1ss_cap_ptr PCI/ASPM: Remove struct aspm_register_info.latency_encoding PCI/ASPM: Remove struct aspm_register_info.enabled PCI/ASPM: Remove struct aspm_register_info.support PCI/ASPM: Use 'parent' and 'child' for readability PCI/ASPM: Move LTR path check to where it's used PCI/ASPM: Move pci_clear_and_set_dword() earlier PCI: dwc: Fix MSI page leakage in suspend/resume ...

PCI: pciehp: Reduce noisiness on hot removal

2020-09-17T21:22:36+00:00

When a PCIe card is hot-removed, the Presence Detect State and Data Link Layer Link Active bits often do not clear simultaneously. I've seen delays of up to 244 msec between the two events with Thunderbolt. After pciehp has brought down the slot in response to the first event, the other bit may still be set. It's not discernible whether it's set because a new card is already in the slot or if it will soon clear. So pciehp tries to bring up the slot and in the latter case fails with a bunch of messages, some of them at KERN_ERR severity. If the slot is no longer occupied, the messages are false positives and annoy users. Stuart Hayes reports the following splat on hot removal: KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up KERN_INFO pcieport 0000:3c:06.0: pciehp: Timeout waiting for Presence Detect KERN_ERR pcieport 0000:3c:06.0: pciehp: link training error: status 0x0001 KERN_ERR pcieport 0000:3c:06.0: pciehp: Failed to check link status Dongdong Liu complains about a similar splat: KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Link Down KERN_INFO iommu: Removing device 0000:87:00.0 from group 12 KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present KERN_INFO pcieport 0000:80:10.0: Data Link Layer Link Active not set in 1000 msec KERN_ERR pciehp 0000:80:10.0:pcie004: Failed to check link status Users are particularly irritated to see a bringup attempt even though the slot was explicitly brought down via sysfs. In a perfect world, we could avoid this by setting Link Disable on slot bringdown and re-enabling it upon a Presence Detect State change. In reality however, there are broken hotplug ports which hardwire Presence Detect to zero, see 80696f991424 ("PCI: pciehp: Tolerate Presence Detect hardwired to zero"). Conversely, PCIe r1.0 hotplug ports hardwire Link Active to zero because Link Active Reporting wasn't specified before PCIe r1.1. On unplug, some ports first clear Presence then Link (see Stuart Hayes' splat) whereas others use the inverse order (see Dongdong Liu's splat). To top it off, there are hotplug ports which flap the Presence and Link bits on slot bringup, see 6c35a1ac3da6 ("PCI: pciehp: Tolerate initially unstable link"). pciehp is designed to work with all of these variants. Surplus attempts at slot bringup are a lesser evil than not being able to bring up slots at all. Although we could try to perfect the behavior for specific hotplug controllers, we'd risk breaking others or increasing code complexity. But we can certainly minimize annoyance by emitting only a single message with KERN_INFO severity if bringup is unsuccessful: * Drop the "Timeout waiting for Presence Detect" message in pcie_wait_for_presence(). The sole caller of that function, pciehp_check_link_status(), ignores the timeout and carries on. It emits error messages of its own and I don't think this particular message adds much value. * There's a single error condition in pciehp_check_link_status() which does not emit a message. Adding one allows dropping the "Failed to check link status" message emitted by board_added() if pciehp_check_link_status() returns a non-zero integer. * Tone down all messages in pciehp_check_link_status() to KERN_INFO severity and rephrase them to look as innocuous as possible. To this end, move the message emitted by pcie_wait_for_link_delay() to its callers. As a result, Stuart Hayes' splat becomes: KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Link Up KERN_INFO pcieport 0000:3c:06.0: pciehp: Slot(180): Cannot train link: status 0x0001 Dongdong Liu's splat becomes: KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): Card present KERN_INFO pciehp 0000:80:10.0:pcie004: Slot(36): No link The messages now merely serve as information that presence or link bits were set a little longer than expected. Bringup failures which are not false positives are still reported, albeit no longer at KERN_ERR severity. Link: https://lore.kernel.org/linux-pci/20200310182100.102987-1-stuart.w.hayes@gmail.com/ Link: https://lore.kernel.org/linux-pci/1547649064-19019-1-git-send-email-liudongdong3@huawei.com/ Link: https://lore.kernel.org/r/b45e46fd8a6aa6930aaac9d7718c2e4b787a4e5e.1595935071.git.lukas@wunner.de Reported-by: Stuart Hayes Reported-by: Dongdong Liu Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Mika Westerberg

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva

PCI: pciehp: Prevent deadlock on disconnect

2019-11-12T23:17:42+00:00

This addresses deadlocks in these common cases in hierarchies containing two switches: - All involved ports are runtime suspended and they are unplugged. This can happen easily if the drivers involved automatically enable runtime PM (xHCI for example does that). - System is suspended (e.g., closing the lid on a laptop) with a dock + something else connected, and the dock is unplugged while suspended. These cases lead to the following deadlock: INFO: task irq/126-pciehp:198 blocked for more than 120 seconds. irq/126-pciehp D 0 198 2 0x80000000 Call Trace: schedule+0x2c/0x80 schedule_timeout+0x246/0x350 wait_for_completion+0xb7/0x140 kthread_stop+0x49/0x110 free_irq+0x32/0x70 pcie_shutdown_notification+0x2f/0x50 pciehp_remove+0x27/0x50 pcie_port_remove_service+0x36/0x50 device_release_driver+0x12/0x20 bus_remove_device+0xec/0x160 device_del+0x13b/0x350 device_unregister+0x1a/0x60 remove_iter+0x1e/0x30 device_for_each_child+0x56/0x90 pcie_port_device_remove+0x22/0x40 pcie_portdrv_remove+0x20/0x60 pci_device_remove+0x3e/0xc0 device_release_driver_internal+0x18c/0x250 device_release_driver+0x12/0x20 pci_stop_bus_device+0x6f/0x90 pci_stop_bus_device+0x31/0x90 pci_stop_and_remove_bus_device+0x12/0x20 pciehp_unconfigure_device+0x88/0x140 pciehp_disable_slot+0x6a/0x110 pciehp_handle_presence_or_link_change+0x263/0x400 pciehp_ist+0x1c9/0x1d0 irq_thread_fn+0x24/0x60 irq_thread+0xeb/0x190 kthread+0x120/0x140 INFO: task irq/190-pciehp:2288 blocked for more than 120 seconds. irq/190-pciehp D 0 2288 2 0x80000000 Call Trace: __schedule+0x2a2/0x880 schedule+0x2c/0x80 schedule_preempt_disabled+0xe/0x10 mutex_lock+0x2c/0x30 pci_lock_rescan_remove+0x15/0x20 pciehp_unconfigure_device+0x4d/0x140 pciehp_disable_slot+0x6a/0x110 pciehp_handle_presence_or_link_change+0x263/0x400 pciehp_ist+0x1c9/0x1d0 irq_thread_fn+0x24/0x60 irq_thread+0xeb/0x190 kthread+0x120/0x140 What happens here is that the whole hierarchy is runtime resumed and the parent PCIe downstream port, which got the hot-remove event, starts removing devices below it, taking pci_lock_rescan_remove() lock. When the child PCIe port is runtime resumed it calls pciehp_check_presence() which ends up calling pciehp_card_present() and pciehp_check_link_active(). Both of these use pcie_capability_read_word(), which notices that the underlying device is already gone and returns PCIBIOS_DEVICE_NOT_FOUND with the capability value set to 0. When pciehp gets this value it thinks that its child device is also hot-removed and schedules its IRQ thread to handle the event. The deadlock happens when the child's IRQ thread runs and tries to acquire pci_lock_rescan_remove() which is already taken by the parent and the parent waits for the child's IRQ thread to finish. Prevent this from happening by checking the return value of pcie_capability_read_word() and if it is PCIBIOS_DEVICE_NOT_FOUND stop performing any hot-removal activities. [bhelgaas: add common scenarios to commit log] Link: https://lore.kernel.org/r/20191029170022.57528-2-mika.westerberg@linux.intel.com Tested-by: Kai-Heng Feng Signed-off-by: Mika Westerberg Signed-off-by: Bjorn Helgaas

PCI: pciehp: Avoid returning prematurely from sysfs requests

2019-10-04T20:39:36+00:00

A sysfs request to enable or disable a PCIe hotplug slot should not return before it has been carried out. That is sought to be achieved by waiting until the controller's "pending_events" have been cleared. However the IRQ thread pciehp_ist() clears the "pending_events" before it acts on them. If pciehp_sysfs_enable_slot() / _disable_slot() happen to check the "pending_events" after they have been cleared but while pciehp_ist() is still running, the functions may return prematurely with an incorrect return value. Fix by introducing an "ist_running" flag which must be false before a sysfs request is allowed to return. Fixes: 32a8cef274fe ("PCI: pciehp: Enable/disable exclusively from IRQ thread") Link: https://lore.kernel.org/linux-pci/1562226638-54134-1-git-send-email-wangxiongfeng2@huawei.com Link: https://lore.kernel.org/r/4174210466e27eb7e2243dd1d801d5f75baaffd8.1565345211.git.lukas@wunner.de Reported-and-tested-by: Xiongfeng Wang Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Cc: stable@vger.kernel.org # v4.19+

PCI: pciehp: Refer to "Indicators" instead of "LEDs" in comments

2019-09-05T20:52:24+00:00

The PCIe spec doesn't mention "green LEDs" or "amber LEDs". Replace those terms with "Power Indicator" and "Attention Indicator" so the comments match the spec language. Comment changes only. Signed-off-by: Bjorn Helgaas

PCI: pciehp: Remove pciehp_green_led_{on,off,blink}()

2019-09-05T20:45:00+00:00

Remove pciehp_green_led_{on,off,blink}() and use pciehp_set_indicators() instead, since the code is mostly the same. [bhelgaas: drop set_power_indicator() wrapper to reduce the number of interfaces] Link: https://lore.kernel.org/r/20190903111021.1559-5-efremov@linux.com Signed-off-by: Denis Efremov Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan

PCI: pciehp: Combine adjacent indicator updates

2019-09-05T20:43:33+00:00

Combine adjacent updates of power and attention indicators into a single pciehp_set_indicators() call. This sends one command to the hotplug controller instead of two. Link: https://lore.kernel.org/r/20190903111021.1559-3-efremov@linux.com Signed-off-by: Denis Efremov Signed-off-by: Bjorn Helgaas Reviewed-by: Kuppuswamy Sathyanarayanan Reviewed-by: Lukas Wunner