From 1d59d474e1cb7d4fdf87dfaf96f44647f13ea590 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Thu, 3 Oct 2024 10:43:41 +0200 Subject: PCI: Hold rescan lock while adding devices during host probe Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and host controller probe functions. The latter need to take the rescan lock when adding devices or we may end up in an undefined state having two incompletely added devices and hit the following crash when trying to remove the device over sysfs: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP Call trace: __pi_strlen+0x14/0x150 kernfs_find_ns+0x80/0x13c kernfs_remove_by_name_ns+0x54/0xf0 sysfs_remove_bin_file+0x24/0x34 pci_remove_resource_files+0x3c/0x84 pci_remove_sysfs_dev_files+0x28/0x38 pci_stop_bus_device+0x8c/0xd8 pci_stop_bus_device+0x40/0xd8 pci_stop_and_remove_bus_device_locked+0x28/0x48 remove_store+0x70/0xb0 dev_attr_store+0x20/0x38 sysfs_kf_write+0x58/0x78 kernfs_fop_write_iter+0xe8/0x184 vfs_write+0x2dc/0x308 ksys_write+0x7c/0xec Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code") Link: https://lore.kernel.org/r/20241003084342.27501-1-brgl@bgdev.pl Reported-by: Konrad Dybcio Tested-by: Konrad Dybcio Signed-off-by: Bartosz Golaszewski Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam --- drivers/pci/probe.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 4f68414c3086..f1615805f5b0 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -3105,7 +3105,9 @@ int pci_host_probe(struct pci_host_bridge *bridge) list_for_each_entry(child, &bus->children, node) pcie_bus_configure_settings(child); + pci_lock_rescan_remove(); pci_bus_add_devices(bus); + pci_unlock_rescan_remove(); return 0; } EXPORT_SYMBOL_GPL(pci_host_probe); -- cgit v1.2.3 From ad783b9f8e78572fff3b04b6caee7bea3821eea8 Mon Sep 17 00:00:00 2001 From: Bartosz Golaszewski Date: Mon, 7 Oct 2024 11:24:46 +0200 Subject: PCI/pwrctl: Abandon QCom WCN probe on pre-pwrseq device-trees Old device trees for some platforms already define wifi nodes for the WCN family of chips since before power sequencing was added upstream. These nodes don't consume the regulator outputs from the PMU, and if we allow this driver to bind to one of such "incomplete" nodes, we'll see a kernel log error about the infinite probe deferral. Extend the driver by adding a platform data struct matched against the compatible. This struct contains the pwrseq target string as well as a validation function called right after entering probe(). For Qualcomm WCN models, check the existence of the regulator supply property that indicates the DT is already using power sequencing and return -ENODEV if it's not there, indicating to the driver model that the device should not be bound to the pwrctl driver. Link: https://lore.kernel.org/r/20241007092447.18616-1-brgl@bgdev.pl Fixes: 6140d185a43d ("PCI/pwrctl: Add a PCI power control driver for power sequenced devices") Reported-by: Johan Hovold Closes: https://lore.kernel.org/all/Zv565olMDDGHyYVt@hovoldconsulting.com/ Signed-off-by: Bartosz Golaszewski Signed-off-by: Bjorn Helgaas --- drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 55 ++++++++++++++++++++++++++++++---- 1 file changed, 50 insertions(+), 5 deletions(-) diff --git a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c index a23a4312574b..0e6bd47671c2 100644 --- a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c +++ b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c @@ -6,9 +6,9 @@ #include #include #include -#include #include #include +#include #include #include #include @@ -18,6 +18,40 @@ struct pci_pwrctl_pwrseq_data { struct pwrseq_desc *pwrseq; }; +struct pci_pwrctl_pwrseq_pdata { + const char *target; + /* + * Called before doing anything else to perform device-specific + * verification between requesting the power sequencing handle. + */ + int (*validate_device)(struct device *dev); +}; + +static int pci_pwrctl_pwrseq_qcm_wcn_validate_device(struct device *dev) +{ + /* + * Old device trees for some platforms already define wifi nodes for + * the WCN family of chips since before power sequencing was added + * upstream. + * + * These nodes don't consume the regulator outputs from the PMU, and + * if we allow this driver to bind to one of such "incomplete" nodes, + * we'll see a kernel log error about the indefinite probe deferral. + * + * Check the existence of the regulator supply that exists on all + * WCN models before moving forward. + */ + if (!device_property_present(dev, "vddaon-supply")) + return -ENODEV; + + return 0; +} + +static const struct pci_pwrctl_pwrseq_pdata pci_pwrctl_pwrseq_qcom_wcn_pdata = { + .target = "wlan", + .validate_device = pci_pwrctl_pwrseq_qcm_wcn_validate_device, +}; + static void devm_pci_pwrctl_pwrseq_power_off(void *data) { struct pwrseq_desc *pwrseq = data; @@ -27,15 +61,26 @@ static void devm_pci_pwrctl_pwrseq_power_off(void *data) static int pci_pwrctl_pwrseq_probe(struct platform_device *pdev) { + const struct pci_pwrctl_pwrseq_pdata *pdata; struct pci_pwrctl_pwrseq_data *data; struct device *dev = &pdev->dev; int ret; + pdata = device_get_match_data(dev); + if (!pdata || !pdata->target) + return -EINVAL; + + if (pdata->validate_device) { + ret = pdata->validate_device(dev); + if (ret) + return ret; + } + data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; - data->pwrseq = devm_pwrseq_get(dev, of_device_get_match_data(dev)); + data->pwrseq = devm_pwrseq_get(dev, pdata->target); if (IS_ERR(data->pwrseq)) return dev_err_probe(dev, PTR_ERR(data->pwrseq), "Failed to get the power sequencer\n"); @@ -64,17 +109,17 @@ static const struct of_device_id pci_pwrctl_pwrseq_of_match[] = { { /* ATH11K in QCA6390 package. */ .compatible = "pci17cb,1101", - .data = "wlan", + .data = &pci_pwrctl_pwrseq_qcom_wcn_pdata, }, { /* ATH11K in WCN6855 package. */ .compatible = "pci17cb,1103", - .data = "wlan", + .data = &pci_pwrctl_pwrseq_qcom_wcn_pdata, }, { /* ATH12K in WCN7850 package. */ .compatible = "pci17cb,1107", - .data = "wlan", + .data = &pci_pwrctl_pwrseq_qcom_wcn_pdata, }, { } }; -- cgit v1.2.3