| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Maximilian Luz | 2407 | 98.97% | 9 | 75.00% |
| Francesco Dolcini | 14 | 0.58% | 1 | 8.33% |
| Andy Shevchenko | 6 | 0.25% | 1 | 8.33% |
| Daniel Scally | 5 | 0.21% | 1 | 8.33% |
| Total | 2432 | 12 |
// SPDX-License-Identifier: GPL-2.0+ /* * Surface Serial Hub (SSH) driver for communication with the Surface/System * Aggregator Module (SSAM/SAM). * * Provides access to a SAM-over-SSH connected EC via a controller device. * Handles communication via requests as well as enabling, disabling, and * relaying of events. * * Copyright (C) 2019-2022 Maximilian Luz <luzmaximilian@gmail.com> */ #include <linux/acpi.h> #include <linux/atomic.h> #include <linux/completion.h> #include <linux/gpio/consumer.h> #include <linux/kernel.h> #include <linux/kref.h> #include <linux/module.h> #include <linux/pm.h> #include <linux/serdev.h> #include <linux/sysfs.h> #include <linux/surface_aggregator/controller.h> #include <linux/surface_aggregator/device.h> #include "bus.h" #include "controller.h" #define CREATE_TRACE_POINTS #include "trace.h" /* -- Static controller reference. ------------------------------------------ */ /* * Main controller reference. The corresponding lock must be held while * accessing (reading/writing) the reference. */ static struct ssam_controller *__ssam_controller; static DEFINE_SPINLOCK(__ssam_controller_lock); /** * ssam_get_controller() - Get reference to SSAM controller. * * Returns a reference to the SSAM controller of the system or %NULL if there * is none, it hasn't been set up yet, or it has already been unregistered. * This function automatically increments the reference count of the * controller, thus the calling party must ensure that ssam_controller_put() * is called when it doesn't need the controller any more. */ struct ssam_controller *ssam_get_controller(void) { struct ssam_controller *ctrl; spin_lock(&__ssam_controller_lock); ctrl = __ssam_controller; if (!ctrl) goto out; if (WARN_ON(!kref_get_unless_zero(&ctrl->kref))) ctrl = NULL; out: spin_unlock(&__ssam_controller_lock); return ctrl; } EXPORT_SYMBOL_GPL(ssam_get_controller); /** * ssam_try_set_controller() - Try to set the main controller reference. * @ctrl: The controller to which the reference should point. * * Set the main controller reference to the given pointer if the reference * hasn't been set already. * * Return: Returns zero on success or %-EEXIST if the reference has already * been set. */ static int ssam_try_set_controller(struct ssam_controller *ctrl) { int status = 0; spin_lock(&__ssam_controller_lock); if (!__ssam_controller) __ssam_controller = ctrl; else status = -EEXIST; spin_unlock(&__ssam_controller_lock); return status; } /** * ssam_clear_controller() - Remove/clear the main controller reference. * * Clears the main controller reference, i.e. sets it to %NULL. This function * should be called before the controller is shut down. */ static void ssam_clear_controller(void) { spin_lock(&__ssam_controller_lock); __ssam_controller = NULL; spin_unlock(&__ssam_controller_lock); } /** * ssam_client_link() - Link an arbitrary client device to the controller. * @c: The controller to link to. * @client: The client device. * * Link an arbitrary client device to the controller by creating a device link * between it as consumer and the controller device as provider. This function * can be used for non-SSAM devices (or SSAM devices not registered as child * under the controller) to guarantee that the controller is valid for as long * as the driver of the client device is bound, and that proper suspend and * resume ordering is guaranteed. * * The device link does not have to be destructed manually. It is removed * automatically once the driver of the client device unbinds. * * Return: Returns zero on success, %-ENODEV if the controller is not ready or * going to be removed soon, or %-ENOMEM if the device link could not be * created for other reasons. */ int ssam_client_link(struct ssam_controller *c, struct device *client) { const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER; struct device_link *link; struct device *ctrldev; ssam_controller_statelock(c); if (c->state != SSAM_CONTROLLER_STARTED) { ssam_controller_stateunlock(c); return -ENODEV; } ctrldev = ssam_controller_device(c); if (!ctrldev) { ssam_controller_stateunlock(c); return -ENODEV; } link = device_link_add(client, ctrldev, flags); if (!link) { ssam_controller_stateunlock(c); return -ENOMEM; } /* * Return -ENODEV if supplier driver is on its way to be removed. In * this case, the controller won't be around for much longer and the * device link is not going to save us any more, as unbinding is * already in progress. */ if (READ_ONCE(link->status) == DL_STATE_SUPPLIER_UNBIND) { ssam_controller_stateunlock(c); return -ENODEV; } ssam_controller_stateunlock(c); return 0; } EXPORT_SYMBOL_GPL(ssam_client_link); /** * ssam_client_bind() - Bind an arbitrary client device to the controller. * @client: The client device. * * Link an arbitrary client device to the controller by creating a device link * between it as consumer and the main controller device as provider. This * function can be used for non-SSAM devices to guarantee that the controller * returned by this function is valid for as long as the driver of the client * device is bound, and that proper suspend and resume ordering is guaranteed. * * This function does essentially the same as ssam_client_link(), except that * it first fetches the main controller reference, then creates the link, and * finally returns this reference. Note that this function does not increment * the reference counter of the controller, as, due to the link, the * controller lifetime is assured as long as the driver of the client device * is bound. * * It is not valid to use the controller reference obtained by this method * outside of the driver bound to the client device at the time of calling * this function, without first incrementing the reference count of the * controller via ssam_controller_get(). Even after doing this, care must be * taken that requests are only submitted and notifiers are only * (un-)registered when the controller is active and not suspended. In other * words: The device link only lives as long as the client driver is bound and * any guarantees enforced by this link (e.g. active controller state) can * only be relied upon as long as this link exists and may need to be enforced * in other ways afterwards. * * The created device link does not have to be destructed manually. It is * removed automatically once the driver of the client device unbinds. * * Return: Returns the controller on success, an error pointer with %-ENODEV * if the controller is not present, not ready or going to be removed soon, or * %-ENOMEM if the device link could not be created for other reasons. */ struct ssam_controller *ssam_client_bind(struct device *client) { struct ssam_controller *c; int status; c = ssam_get_controller(); if (!c) return ERR_PTR(-ENODEV); status = ssam_client_link(c, client); /* * Note that we can drop our controller reference in both success and * failure cases: On success, we have bound the controller lifetime * inherently to the client driver lifetime, i.e. it the controller is * now guaranteed to outlive the client driver. On failure, we're not * going to use the controller any more. */ ssam_controller_put(c); return status >= 0 ? c : ERR_PTR(status); } EXPORT_SYMBOL_GPL(ssam_client_bind); /* -- Glue layer (serdev_device -> ssam_controller). ------------------------ */ static int ssam_receive_buf(struct serdev_device *dev, const unsigned char *buf, size_t n) { struct ssam_controller *ctrl; int ret; ctrl = serdev_device_get_drvdata(dev); ret = ssam_controller_receive_buf(ctrl, buf, n); return ret < 0 ? 0 : ret; } static void ssam_write_wakeup(struct serdev_device *dev) { ssam_controller_write_wakeup(serdev_device_get_drvdata(dev)); } static const struct serdev_device_ops ssam_serdev_ops = { .receive_buf = ssam_receive_buf, .write_wakeup = ssam_write_wakeup, }; /* -- SysFS and misc. ------------------------------------------------------- */ static int ssam_log_firmware_version(struct ssam_controller *ctrl) { u32 version, a, b, c; int status; status = ssam_get_firmware_version(ctrl, &version); if (status) return status; a = (version >> 24) & 0xff; b = ((version >> 8) & 0xffff); c = version & 0xff; ssam_info(ctrl, "SAM firmware version: %u.%u.%u\n", a, b, c); return 0; } static ssize_t firmware_version_show(struct device *dev, struct device_attribute *attr, char *buf) { struct ssam_controller *ctrl = dev_get_drvdata(dev); u32 version, a, b, c; int status; status = ssam_get_firmware_version(ctrl, &version); if (status < 0) return status; a = (version >> 24) & 0xff; b = ((version >> 8) & 0xffff); c = version & 0xff; return sysfs_emit(buf, "%u.%u.%u\n", a, b, c); } static DEVICE_ATTR_RO(firmware_version); static struct attribute *ssam_sam_attrs[] = { &dev_attr_firmware_version.attr, NULL }; static const struct attribute_group ssam_sam_group = { .name = "sam", .attrs = ssam_sam_attrs, }; /* -- ACPI based device setup. ---------------------------------------------- */ static acpi_status ssam_serdev_setup_via_acpi_crs(struct acpi_resource *rsc, void *ctx) { struct serdev_device *serdev = ctx; struct acpi_resource_uart_serialbus *uart; bool flow_control; int status = 0; if (!serdev_acpi_get_uart_resource(rsc, &uart)) return AE_OK; /* Set up serdev device. */ serdev_device_set_baudrate(serdev, uart->default_baud_rate); /* serdev currently only supports RTSCTS flow control. */ if (uart->flow_control & (~((u8)ACPI_UART_FLOW_CONTROL_HW))) { dev_warn(&serdev->dev, "setup: unsupported flow control (value: %#04x)\n", uart->flow_control); } /* Set RTSCTS flow control. */ flow_control = uart->flow_control & ACPI_UART_FLOW_CONTROL_HW; serdev_device_set_flow_control(serdev, flow_control); /* serdev currently only supports EVEN/ODD parity. */ switch (uart->parity) { case ACPI_UART_PARITY_NONE: status = serdev_device_set_parity(serdev, SERDEV_PARITY_NONE); break; case ACPI_UART_PARITY_EVEN: status = serdev_device_set_parity(serdev, SERDEV_PARITY_EVEN); break; case ACPI_UART_PARITY_ODD: status = serdev_device_set_parity(serdev, SERDEV_PARITY_ODD); break; default: dev_warn(&serdev->dev, "setup: unsupported parity (value: %#04x)\n", uart->parity); break; } if (status) { dev_err(&serdev->dev, "setup: failed to set parity (value: %#04x, error: %d)\n", uart->parity, status); return AE_ERROR; } /* We've found the resource and are done. */ return AE_CTRL_TERMINATE; } static acpi_status ssam_serdev_setup_via_acpi(acpi_handle handle, struct serdev_device *serdev) { return acpi_walk_resources(handle, METHOD_NAME__CRS, ssam_serdev_setup_via_acpi_crs, serdev); } /* -- Power management. ----------------------------------------------------- */ static void ssam_serial_hub_shutdown(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * Try to disable notifiers, signal display-off and D0-exit, ignore any * errors. * * Note: It has not been established yet if this is actually * necessary/useful for shutdown. */ status = ssam_notifier_disable_registered(c); if (status) { ssam_err(c, "pm: failed to disable notifiers for shutdown: %d\n", status); } status = ssam_ctrl_notif_display_off(c); if (status) ssam_err(c, "pm: display-off notification failed: %d\n", status); status = ssam_ctrl_notif_d0_exit(c); if (status) ssam_err(c, "pm: D0-exit notification failed: %d\n", status); } #ifdef CONFIG_PM_SLEEP static int ssam_serial_hub_pm_prepare(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * Try to signal display-off, This will quiesce events. * * Note: Signaling display-off/display-on should normally be done from * some sort of display state notifier. As that is not available, * signal it here. */ status = ssam_ctrl_notif_display_off(c); if (status) ssam_err(c, "pm: display-off notification failed: %d\n", status); return status; } static void ssam_serial_hub_pm_complete(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * Try to signal display-on. This will restore events. * * Note: Signaling display-off/display-on should normally be done from * some sort of display state notifier. As that is not available, * signal it here. */ status = ssam_ctrl_notif_display_on(c); if (status) ssam_err(c, "pm: display-on notification failed: %d\n", status); } static int ssam_serial_hub_pm_suspend(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * Try to signal D0-exit, enable IRQ wakeup if specified. Abort on * error. */ status = ssam_ctrl_notif_d0_exit(c); if (status) { ssam_err(c, "pm: D0-exit notification failed: %d\n", status); goto err_notif; } status = ssam_irq_arm_for_wakeup(c); if (status) goto err_irq; WARN_ON(ssam_controller_suspend(c)); return 0; err_irq: ssam_ctrl_notif_d0_entry(c); err_notif: ssam_ctrl_notif_display_on(c); return status; } static int ssam_serial_hub_pm_resume(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; WARN_ON(ssam_controller_resume(c)); /* * Try to disable IRQ wakeup (if specified) and signal D0-entry. In * case of errors, log them and try to restore normal operation state * as far as possible. * * Note: Signaling display-off/display-on should normally be done from * some sort of display state notifier. As that is not available, * signal it here. */ ssam_irq_disarm_wakeup(c); status = ssam_ctrl_notif_d0_entry(c); if (status) ssam_err(c, "pm: D0-entry notification failed: %d\n", status); return 0; } static int ssam_serial_hub_pm_freeze(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * During hibernation image creation, we only have to ensure that the * EC doesn't send us any events. This is done via the display-off * and D0-exit notifications. Note that this sets up the wakeup IRQ * on the EC side, however, we have disabled it by default on our side * and won't enable it here. * * See ssam_serial_hub_poweroff() for more details on the hibernation * process. */ status = ssam_ctrl_notif_d0_exit(c); if (status) { ssam_err(c, "pm: D0-exit notification failed: %d\n", status); ssam_ctrl_notif_display_on(c); return status; } WARN_ON(ssam_controller_suspend(c)); return 0; } static int ssam_serial_hub_pm_thaw(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; WARN_ON(ssam_controller_resume(c)); status = ssam_ctrl_notif_d0_entry(c); if (status) ssam_err(c, "pm: D0-exit notification failed: %d\n", status); return status; } static int ssam_serial_hub_pm_poweroff(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * When entering hibernation and powering off the system, the EC, at * least on some models, may disable events. Without us taking care of * that, this leads to events not being enabled/restored when the * system resumes from hibernation, resulting SAM-HID subsystem devices * (i.e. keyboard, touchpad) not working, AC-plug/AC-unplug events being * gone, etc. * * To avoid these issues, we disable all registered events here (this is * likely not actually required) and restore them during the drivers PM * restore callback. * * Wakeup from the EC interrupt is not supported during hibernation, * so don't arm the IRQ here. */ status = ssam_notifier_disable_registered(c); if (status) { ssam_err(c, "pm: failed to disable notifiers for hibernation: %d\n", status); return status; } status = ssam_ctrl_notif_d0_exit(c); if (status) { ssam_err(c, "pm: D0-exit notification failed: %d\n", status); ssam_notifier_restore_registered(c); return status; } WARN_ON(ssam_controller_suspend(c)); return 0; } static int ssam_serial_hub_pm_restore(struct device *dev) { struct ssam_controller *c = dev_get_drvdata(dev); int status; /* * Ignore but log errors, try to restore state as much as possible in * case of failures. See ssam_serial_hub_poweroff() for more details on * the hibernation process. */ WARN_ON(ssam_controller_resume(c)); status = ssam_ctrl_notif_d0_entry(c); if (status) ssam_err(c, "pm: D0-entry notification failed: %d\n", status); ssam_notifier_restore_registered(c); return 0; } static const struct dev_pm_ops ssam_serial_hub_pm_ops = { .prepare = ssam_serial_hub_pm_prepare, .complete = ssam_serial_hub_pm_complete, .suspend = ssam_serial_hub_pm_suspend, .resume = ssam_serial_hub_pm_resume, .freeze = ssam_serial_hub_pm_freeze, .thaw = ssam_serial_hub_pm_thaw, .poweroff = ssam_serial_hub_pm_poweroff, .restore = ssam_serial_hub_pm_restore, }; #else /* CONFIG_PM_SLEEP */ static const struct dev_pm_ops ssam_serial_hub_pm_ops = { }; #endif /* CONFIG_PM_SLEEP */ /* -- Device/driver setup. -------------------------------------------------- */ static const struct acpi_gpio_params gpio_ssam_wakeup_int = { 0, 0, false }; static const struct acpi_gpio_params gpio_ssam_wakeup = { 1, 0, false }; static const struct acpi_gpio_mapping ssam_acpi_gpios[] = { { "ssam_wakeup-int-gpio", &gpio_ssam_wakeup_int, 1 }, { "ssam_wakeup-gpio", &gpio_ssam_wakeup, 1 }, { }, }; static int ssam_serial_hub_probe(struct serdev_device *serdev) { struct acpi_device *ssh = ACPI_COMPANION(&serdev->dev); struct ssam_controller *ctrl; acpi_status astatus; int status; if (gpiod_count(&serdev->dev, NULL) < 0) return -ENODEV; status = devm_acpi_dev_add_driver_gpios(&serdev->dev, ssam_acpi_gpios); if (status) return status; /* Allocate controller. */ ctrl = kzalloc(sizeof(*ctrl), GFP_KERNEL); if (!ctrl) return -ENOMEM; /* Initialize controller. */ status = ssam_controller_init(ctrl, serdev); if (status) goto err_ctrl_init; ssam_controller_lock(ctrl); /* Set up serdev device. */ serdev_device_set_drvdata(serdev, ctrl); serdev_device_set_client_ops(serdev, &ssam_serdev_ops); status = serdev_device_open(serdev); if (status) goto err_devopen; astatus = ssam_serdev_setup_via_acpi(ssh->handle, serdev); if (ACPI_FAILURE(astatus)) { status = -ENXIO; goto err_devinit; } /* Start controller. */ status = ssam_controller_start(ctrl); if (status) goto err_devinit; ssam_controller_unlock(ctrl); /* * Initial SAM requests: Log version and notify default/init power * states. */ status = ssam_log_firmware_version(ctrl); if (status) goto err_initrq; status = ssam_ctrl_notif_d0_entry(ctrl); if (status) goto err_initrq; status = ssam_ctrl_notif_display_on(ctrl); if (status) goto err_initrq; status = sysfs_create_group(&serdev->dev.kobj, &ssam_sam_group); if (status) goto err_initrq; /* Set up IRQ. */ status = ssam_irq_setup(ctrl); if (status) goto err_irq; /* Finally, set main controller reference. */ status = ssam_try_set_controller(ctrl); if (WARN_ON(status)) /* Currently, we're the only provider. */ goto err_mainref; /* * TODO: The EC can wake up the system via the associated GPIO interrupt * in multiple situations. One of which is the remaining battery * capacity falling below a certain threshold. Normally, we should * use the device_init_wakeup function, however, the EC also seems * to have other reasons for waking up the system and it seems * that Windows has additional checks whether the system should be * resumed. In short, this causes some spurious unwanted wake-ups. * For now let's thus default power/wakeup to false. */ device_set_wakeup_capable(&serdev->dev, true); acpi_dev_clear_dependencies(ssh); return 0; err_mainref: ssam_irq_free(ctrl); err_irq: sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group); err_initrq: ssam_controller_lock(ctrl); ssam_controller_shutdown(ctrl); err_devinit: serdev_device_close(serdev); err_devopen: ssam_controller_destroy(ctrl); ssam_controller_unlock(ctrl); err_ctrl_init: kfree(ctrl); return status; } static void ssam_serial_hub_remove(struct serdev_device *serdev) { struct ssam_controller *ctrl = serdev_device_get_drvdata(serdev); int status; /* Clear static reference so that no one else can get a new one. */ ssam_clear_controller(); /* Disable and free IRQ. */ ssam_irq_free(ctrl); sysfs_remove_group(&serdev->dev.kobj, &ssam_sam_group); ssam_controller_lock(ctrl); /* Remove all client devices. */ ssam_remove_clients(&serdev->dev); /* Act as if suspending to silence events. */ status = ssam_ctrl_notif_display_off(ctrl); if (status) { dev_err(&serdev->dev, "display-off notification failed: %d\n", status); } status = ssam_ctrl_notif_d0_exit(ctrl); if (status) { dev_err(&serdev->dev, "D0-exit notification failed: %d\n", status); } /* Shut down controller and remove serdev device reference from it. */ ssam_controller_shutdown(ctrl); /* Shut down actual transport. */ serdev_device_wait_until_sent(serdev, 0); serdev_device_close(serdev); /* Drop our controller reference. */ ssam_controller_unlock(ctrl); ssam_controller_put(ctrl); device_set_wakeup_capable(&serdev->dev, false); } static const struct acpi_device_id ssam_serial_hub_match[] = { { "MSHW0084", 0 }, { }, }; MODULE_DEVICE_TABLE(acpi, ssam_serial_hub_match); static struct serdev_device_driver ssam_serial_hub = { .probe = ssam_serial_hub_probe, .remove = ssam_serial_hub_remove, .driver = { .name = "surface_serial_hub", .acpi_match_table = ssam_serial_hub_match, .pm = &ssam_serial_hub_pm_ops, .shutdown = ssam_serial_hub_shutdown, .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, }; /* -- Module setup. --------------------------------------------------------- */ static int __init ssam_core_init(void) { int status; status = ssam_bus_register(); if (status) goto err_bus; status = ssh_ctrl_packet_cache_init(); if (status) goto err_cpkg; status = ssam_event_item_cache_init(); if (status) goto err_evitem; status = serdev_device_driver_register(&ssam_serial_hub); if (status) goto err_register; return 0; err_register: ssam_event_item_cache_destroy(); err_evitem: ssh_ctrl_packet_cache_destroy(); err_cpkg: ssam_bus_unregister(); err_bus: return status; } subsys_initcall(ssam_core_init); static void __exit ssam_core_exit(void) { serdev_device_driver_unregister(&ssam_serial_hub); ssam_event_item_cache_destroy(); ssh_ctrl_packet_cache_destroy(); ssam_bus_unregister(); } module_exit(ssam_core_exit); MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>"); MODULE_DESCRIPTION("Subsystem and Surface Serial Hub driver for Surface System Aggregator Module"); MODULE_LICENSE("GPL");
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