// SPDX-License-Identifier: GPL-2.0-only /* * Driver for onboard USB hubs * * Copyright (c) 2022, Google LLC */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "onboard_usb_hub.h" static void onboard_hub_attach_usb_driver(struct work_struct *work); static struct usb_device_driver onboard_hub_usbdev_driver; static DECLARE_WORK(attach_usb_driver_work, onboard_hub_attach_usb_driver); /************************** Platform driver **************************/ struct usbdev_node { struct usb_device *udev; struct list_head list; }; struct onboard_hub { struct regulator *vdd; struct device *dev; const struct onboard_hub_pdata *pdata; struct gpio_desc *reset_gpio; bool always_powered_in_suspend; bool is_powered_on; bool going_away; struct list_head udev_list; struct mutex lock; }; static int onboard_hub_power_on(struct onboard_hub *hub) { int err; err = regulator_enable(hub->vdd); if (err) { dev_err(hub->dev, "failed to enable regulator: %d\n", err); return err; } fsleep(hub->pdata->reset_us); gpiod_set_value_cansleep(hub->reset_gpio, 0); hub->is_powered_on = true; return 0; } static int onboard_hub_power_off(struct onboard_hub *hub) { int err; gpiod_set_value_cansleep(hub->reset_gpio, 1); err = regulator_disable(hub->vdd); if (err) { dev_err(hub->dev, "failed to disable regulator: %d\n", err); return err; } hub->is_powered_on = false; return 0; } static int __maybe_unused onboard_hub_suspend(struct device *dev) { struct onboard_hub *hub = dev_get_drvdata(dev); struct usbdev_node *node; bool power_off = true; if (hub->always_powered_in_suspend) return 0; mutex_lock(&hub->lock); list_for_each_entry(node, &hub->udev_list, list) { if (!device_may_wakeup(node->udev->bus->controller)) continue; if (usb_wakeup_enabled_descendants(node->udev)) { power_off = false; break; } } mutex_unlock(&hub->lock); if (!power_off) return 0; return onboard_hub_power_off(hub); } static int __maybe_unused onboard_hub_resume(struct device *dev) { struct onboard_hub *hub = dev_get_drvdata(dev); if (hub->is_powered_on) return 0; return onboard_hub_power_on(hub); } static inline void get_udev_link_name(const struct usb_device *udev, char *buf, size_t size) { snprintf(buf, size, "usb_dev.%s", dev_name(&udev->dev)); } static int onboard_hub_add_usbdev(struct onboard_hub *hub, struct usb_device *udev) { struct usbdev_node *node; char link_name[64]; int err; mutex_lock(&hub->lock); if (hub->going_away) { err = -EINVAL; goto error; } node = kzalloc(sizeof(*node), GFP_KERNEL); if (!node) { err = -ENOMEM; goto error; } node->udev = udev; list_add(&node->list, &hub->udev_list); mutex_unlock(&hub->lock); get_udev_link_name(udev, link_name, sizeof(link_name)); WARN_ON(sysfs_create_link(&hub->dev->kobj, &udev->dev.kobj, link_name)); return 0; error: mutex_unlock(&hub->lock); return err; } static void onboard_hub_remove_usbdev(struct onboard_hub *hub, const struct usb_device *udev) { struct usbdev_node *node; char link_name[64]; get_udev_link_name(udev, link_name, sizeof(link_name)); sysfs_remove_link(&hub->dev->kobj, link_name); mutex_lock(&hub->lock); list_for_each_entry(node, &hub->udev_list, list) { if (node->udev == udev) { list_del(&node->list); kfree(node); break; } } mutex_unlock(&hub->lock); } static ssize_t always_powered_in_suspend_show(struct device *dev, struct device_attribute *attr, char *buf) { const struct onboard_hub *hub = dev_get_drvdata(dev); return sysfs_emit(buf, "%d\n", hub->always_powered_in_suspend); } static ssize_t always_powered_in_suspend_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct onboard_hub *hub = dev_get_drvdata(dev); bool val; int ret; ret = kstrtobool(buf, &val); if (ret < 0) return ret; hub->always_powered_in_suspend = val; return count; } static DEVICE_ATTR_RW(always_powered_in_suspend); static struct attribute *onboard_hub_attrs[] = { &dev_attr_always_powered_in_suspend.attr, NULL, }; ATTRIBUTE_GROUPS(onboard_hub); static void onboard_hub_attach_usb_driver(struct work_struct *work) { int err; err = driver_attach(&onboard_hub_usbdev_driver.drvwrap.driver); if (err) pr_err("Failed to attach USB driver: %d\n", err); } static int onboard_hub_probe(struct platform_device *pdev) { const struct of_device_id *of_id; struct device *dev = &pdev->dev; struct onboard_hub *hub; int err; hub = devm_kzalloc(dev, sizeof(*hub), GFP_KERNEL); if (!hub) return -ENOMEM; of_id = of_match_device(onboard_hub_match, &pdev->dev); if (!of_id) return -ENODEV; hub->pdata = of_id->data; if (!hub->pdata) return -EINVAL; hub->vdd = devm_regulator_get(dev, "vdd"); if (IS_ERR(hub->vdd)) return PTR_ERR(hub->vdd); hub->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); if (IS_ERR(hub->reset_gpio)) return dev_err_probe(dev, PTR_ERR(hub->reset_gpio), "failed to get reset GPIO\n"); hub->dev = dev; mutex_init(&hub->lock); INIT_LIST_HEAD(&hub->udev_list); dev_set_drvdata(dev, hub); err = onboard_hub_power_on(hub); if (err) return err; /* * The USB driver might have been detached from the USB devices by * onboard_hub_remove() (e.g. through an 'unbind' by userspace), * make sure to re-attach it if needed. * * This needs to be done deferred to avoid self-deadlocks on systems * with nested onboard hubs. */ schedule_work(&attach_usb_driver_work); return 0; } static int onboard_hub_remove(struct platform_device *pdev) { struct onboard_hub *hub = dev_get_drvdata(&pdev->dev); struct usbdev_node *node; struct usb_device *udev; hub->going_away = true; mutex_lock(&hub->lock); /* unbind the USB devices to avoid dangling references to this device */ while (!list_empty(&hub->udev_list)) { node = list_first_entry(&hub->udev_list, struct usbdev_node, list); udev = node->udev; /* * Unbinding the driver will call onboard_hub_remove_usbdev(), * which acquires hub->lock. We must release the lock first. */ get_device(&udev->dev); mutex_unlock(&hub->lock); device_release_driver(&udev->dev); put_device(&udev->dev); mutex_lock(&hub->lock); } mutex_unlock(&hub->lock); return onboard_hub_power_off(hub); } MODULE_DEVICE_TABLE(of, onboard_hub_match); static const struct dev_pm_ops __maybe_unused onboard_hub_pm_ops = { SET_LATE_SYSTEM_SLEEP_PM_OPS(onboard_hub_suspend, onboard_hub_resume) }; static struct platform_driver onboard_hub_driver = { .probe = onboard_hub_probe, .remove = onboard_hub_remove, .driver = { .name = "onboard-usb-hub", .of_match_table = onboard_hub_match, .pm = pm_ptr(&onboard_hub_pm_ops), .dev_groups = onboard_hub_groups, }, }; /************************** USB driver **************************/ #define VENDOR_ID_MICROCHIP 0x0424 #define VENDOR_ID_REALTEK 0x0bda #define VENDOR_ID_TI 0x0451 /* * Returns the onboard_hub platform device that is associated with the USB * device passed as parameter. */ static struct onboard_hub *_find_onboard_hub(struct device *dev) { struct platform_device *pdev; struct device_node *np; struct onboard_hub *hub; pdev = of_find_device_by_node(dev->of_node); if (!pdev) { np = of_parse_phandle(dev->of_node, "peer-hub", 0); if (!np) { dev_err(dev, "failed to find device node for peer hub\n"); return ERR_PTR(-EINVAL); } pdev = of_find_device_by_node(np); of_node_put(np); if (!pdev) return ERR_PTR(-ENODEV); } hub = dev_get_drvdata(&pdev->dev); put_device(&pdev->dev); /* * The presence of drvdata ('hub') indicates that the platform driver * finished probing. This handles the case where (conceivably) we could * be running at the exact same time as the platform driver's probe. If * we detect the race we request probe deferral and we'll come back and * try again. */ if (!hub) return ERR_PTR(-EPROBE_DEFER); return hub; } static int onboard_hub_usbdev_probe(struct usb_device *udev) { struct device *dev = &udev->dev; struct onboard_hub *hub; int err; /* ignore supported hubs without device tree node */ if (!dev->of_node) return -ENODEV; hub = _find_onboard_hub(dev); if (IS_ERR(hub)) return PTR_ERR(hub); dev_set_drvdata(dev, hub); err = onboard_hub_add_usbdev(hub, udev); if (err) return err; return 0; } static void onboard_hub_usbdev_disconnect(struct usb_device *udev) { struct onboard_hub *hub = dev_get_drvdata(&udev->dev); onboard_hub_remove_usbdev(hub, udev); } static const struct usb_device_id onboard_hub_id_table[] = { { USB_DEVICE(VENDOR_ID_MICROCHIP, 0x2514) }, /* USB2514B USB 2.0 */ { USB_DEVICE(VENDOR_ID_REALTEK, 0x0411) }, /* RTS5411 USB 3.1 */ { USB_DEVICE(VENDOR_ID_REALTEK, 0x5411) }, /* RTS5411 USB 2.1 */ { USB_DEVICE(VENDOR_ID_REALTEK, 0x0414) }, /* RTS5414 USB 3.2 */ { USB_DEVICE(VENDOR_ID_REALTEK, 0x5414) }, /* RTS5414 USB 2.1 */ { USB_DEVICE(VENDOR_ID_TI, 0x8140) }, /* TI USB8041 3.0 */ { USB_DEVICE(VENDOR_ID_TI, 0x8142) }, /* TI USB8041 2.0 */ {} }; MODULE_DEVICE_TABLE(usb, onboard_hub_id_table); static struct usb_device_driver onboard_hub_usbdev_driver = { .name = "onboard-usb-hub", .probe = onboard_hub_usbdev_probe, .disconnect = onboard_hub_usbdev_disconnect, .generic_subclass = 1, .supports_autosuspend = 1, .id_table = onboard_hub_id_table, }; static int __init onboard_hub_init(void) { int ret; ret = usb_register_device_driver(&onboard_hub_usbdev_driver, THIS_MODULE); if (ret) return ret; ret = platform_driver_register(&onboard_hub_driver); if (ret) usb_deregister_device_driver(&onboard_hub_usbdev_driver); return ret; } module_init(onboard_hub_init); static void __exit onboard_hub_exit(void) { usb_deregister_device_driver(&onboard_hub_usbdev_driver); platform_driver_unregister(&onboard_hub_driver); cancel_work_sync(&attach_usb_driver_work); } module_exit(onboard_hub_exit); MODULE_AUTHOR("Matthias Kaehlcke "); MODULE_DESCRIPTION("Driver for discrete onboard USB hubs"); MODULE_LICENSE("GPL v2");