diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c index 9db93f500b4e..42d1dae34b21 100644 --- a/drivers/tty/serdev/core.c +++ b/drivers/tty/serdev/core.c @@ -496,16 +496,97 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl) } #ifdef CONFIG_ACPI + +#define SERDEV_ACPI_MAX_SCAN_DEPTH 32 + +struct acpi_serdev_lookup { + acpi_handle device_handle; + acpi_handle controller_handle; + int n; + int index; +}; + +static int acpi_serdev_parse_resource(struct acpi_resource *ares, void *data) +{ + struct acpi_serdev_lookup *lookup = data; + struct acpi_resource_uart_serialbus *sb; + acpi_status status; + + if (ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) + return 1; + + if (ares->data.common_serial_bus.type != ACPI_RESOURCE_SERIAL_TYPE_UART) + return 1; + + if (lookup->index != -1 && lookup->n++ != lookup->index) + return 1; + + sb = &ares->data.uart_serial_bus; + + status = acpi_get_handle(lookup->device_handle, + sb->resource_source.string_ptr, + &lookup->controller_handle); + if (ACPI_FAILURE(status)) + return 1; + + /* + * NOTE: Ideally, we would also want to retreive other properties here, + * once setting them before opening the device is supported by serdev. + */ + + return 1; +} + +static int acpi_serdev_do_lookup(struct acpi_device *adev, + struct acpi_serdev_lookup *lookup) +{ + struct list_head resource_list; + int ret; + + lookup->device_handle = acpi_device_handle(adev); + lookup->controller_handle = NULL; + lookup->n = 0; + + INIT_LIST_HEAD(&resource_list); + ret = acpi_dev_get_resources(adev, &resource_list, + acpi_serdev_parse_resource, lookup); + acpi_dev_free_resource_list(&resource_list); + + if (ret < 0) + return -EINVAL; + + return 0; +} + +static int acpi_serdev_check_resources(struct serdev_controller *ctrl, + struct acpi_device *adev) +{ + struct acpi_serdev_lookup lookup; + int ret; + + if (acpi_bus_get_status(adev) || !adev->status.present) + return -EINVAL; + + /* Look for UARTSerialBusV2 resource */ + lookup.index = -1; // we only care for the last device + + ret = acpi_serdev_do_lookup(adev, &lookup); + if (ret) + return ret; + + /* Make sure controller and ResourceSource handle match */ + if (ACPI_HANDLE(ctrl->dev.parent) != lookup.controller_handle) + return -ENODEV; + + return 0; +} + static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl, - struct acpi_device *adev) + struct acpi_device *adev) { - struct serdev_device *serdev = NULL; + struct serdev_device *serdev; int err; - if (acpi_bus_get_status(adev) || !adev->status.present || - acpi_device_enumerated(adev)) - return AE_OK; - serdev = serdev_device_alloc(ctrl); if (!serdev) { dev_err(&ctrl->dev, "failed to allocate serdev device for %s\n", @@ -527,7 +608,7 @@ static acpi_status acpi_serdev_register_device(struct serdev_controller *ctrl, } static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level, - void *data, void **return_value) + void *data, void **return_value) { struct serdev_controller *ctrl = data; struct acpi_device *adev; @@ -535,22 +616,28 @@ static acpi_status acpi_serdev_add_device(acpi_handle handle, u32 level, if (acpi_bus_get_device(handle, &adev)) return AE_OK; + if (acpi_device_enumerated(adev)) + return AE_OK; + + if (acpi_serdev_check_resources(ctrl, adev)) + return AE_OK; + return acpi_serdev_register_device(ctrl, adev); } + static int acpi_serdev_register_devices(struct serdev_controller *ctrl) { acpi_status status; - acpi_handle handle; - handle = ACPI_HANDLE(ctrl->dev.parent); - if (!handle) + if (!has_acpi_companion(ctrl->dev.parent)) return -ENODEV; - status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1, + status = acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, + SERDEV_ACPI_MAX_SCAN_DEPTH, acpi_serdev_add_device, NULL, ctrl, NULL); if (ACPI_FAILURE(status)) - dev_dbg(&ctrl->dev, "failed to enumerate serdev slaves\n"); + dev_warn(&ctrl->dev, "failed to enumerate serdev slaves\n"); if (!ctrl->serdev) return -ENODEV;