text: // SPDX-License-Identifier: GPL-2.0
  /*
   * Greybus CPort control protocol.
   *
   * Copyright 2015 Google Inc.
   * Copyright 2015 Linaro Ltd.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/greybus.h>
  
  /* Highest control-protocol version supported */
  #define GB_CONTROL_VERSION_MAJOR	0
  #define GB_CONTROL_VERSION_MINOR	1
  
  static int gb_control_get_version(struct gb_control *control)
  {
  	struct gb_interface *intf = control->connection->intf;
  	struct gb_control_version_request request;
  	struct gb_control_version_response response;
  	int ret;
  
  	request.major = GB_CONTROL_VERSION_MAJOR;
  	request.minor = GB_CONTROL_VERSION_MINOR;
  
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_VERSION,
  				&request, sizeof(request), &response,
  				sizeof(response));
  	if (ret) {
  		dev_err(&intf->dev,
  			"failed to get control-protocol version: %d\n",
  			ret);
  		return ret;
  	}
  
  	if (response.major > request.major) {
  		dev_err(&intf->dev,
  			"unsupported major control-protocol version (%u > %u)\n",
  			response.major, request.major);
  		return -ENOTSUPP;
  	}
  
  	control->protocol_major = response.major;
  	control->protocol_minor = response.minor;
  
  	dev_dbg(&intf->dev, "%s - %u.%u\n", __func__, response.major,
  		response.minor);
  
  	return 0;
  }
  
  static int gb_control_get_bundle_version(struct gb_control *control,
  					 struct gb_bundle *bundle)
  {
  	struct gb_interface *intf = control->connection->intf;
  	struct gb_control_bundle_version_request request;
  	struct gb_control_bundle_version_response response;
  	int ret;
  
  	request.bundle_id = bundle->id;
  
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_BUNDLE_VERSION,
  				&request, sizeof(request),
  				&response, sizeof(response));
  	if (ret) {
  		dev_err(&intf->dev,
  			"failed to get bundle %u class version: %d\n",
  			bundle->id, ret);
  		return ret;
  	}
  
  	bundle->class_major = response.major;
  	bundle->class_minor = response.minor;
  
  	dev_dbg(&intf->dev, "%s - %u: %u.%u\n", __func__, bundle->id,
  		response.major, response.minor);
  
  	return 0;
  }
  
  int gb_control_get_bundle_versions(struct gb_control *control)
  {
  	struct gb_interface *intf = control->connection->intf;
  	struct gb_bundle *bundle;
  	int ret;
  
  	if (!control->has_bundle_version)
  		return 0;
  
  	list_for_each_entry(bundle, &intf->bundles, links) {
  		ret = gb_control_get_bundle_version(control, bundle);
  		if (ret)
  			return ret;
  	}
  
  	return 0;
  }
  
  /* Get Manifest's size from the interface */
  int gb_control_get_manifest_size_operation(struct gb_interface *intf)
  {
  	struct gb_control_get_manifest_size_response response;
  	struct gb_connection *connection = intf->control->connection;
  	int ret;
  
  	ret = gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST_SIZE,
  				NULL, 0, &response, sizeof(response));
  	if (ret) {
  		dev_err(&connection->intf->dev,
  			"failed to get manifest size: %d\n", ret);
  		return ret;
  	}
  
  	return le16_to_cpu(response.size);
  }
  
  /* Reads Manifest from the interface */
  int gb_control_get_manifest_operation(struct gb_interface *intf, void *manifest,
  				      size_t size)
  {
  	struct gb_connection *connection = intf->control->connection;
  
  	return gb_operation_sync(connection, GB_CONTROL_TYPE_GET_MANIFEST,
  				NULL, 0, manifest, size);
  }
  
  int gb_control_connected_operation(struct gb_control *control, u16 cport_id)
  {
  	struct gb_control_connected_request request;
  
  	request.cport_id = cpu_to_le16(cport_id);
  	return gb_operation_sync(control->connection, GB_CONTROL_TYPE_CONNECTED,
  				 &request, sizeof(request), NULL, 0);
  }
  
  int gb_control_disconnected_operation(struct gb_control *control, u16 cport_id)
  {
  	struct gb_control_disconnected_request request;
  
  	request.cport_id = cpu_to_le16(cport_id);
  	return gb_operation_sync(control->connection,
  				 GB_CONTROL_TYPE_DISCONNECTED, &request,
  				 sizeof(request), NULL, 0);
  }
  
  int gb_control_disconnecting_operation(struct gb_control *control,
  				       u16 cport_id)
  {
  	struct gb_control_disconnecting_request *request;
  	struct gb_operation *operation;
  	int ret;
  
  	operation = gb_operation_create_core(control->connection,
  					     GB_CONTROL_TYPE_DISCONNECTING,
  					     sizeof(*request), 0, 0,
  					     GFP_KERNEL);
  	if (!operation)
  		return -ENOMEM;
  
  	request = operation->request->payload;
  	request->cport_id = cpu_to_le16(cport_id);
  
  	ret = gb_operation_request_send_sync(operation);
  	if (ret) {
  		dev_err(&control->dev, "failed to send disconnecting: %d\n",
  			ret);
  	}
  
  	gb_operation_put(operation);
  
  	return ret;
  }
  
  int gb_control_mode_switch_operation(struct gb_control *control)
  {
  	struct gb_operation *operation;
  	int ret;
  
  	operation = gb_operation_create_core(control->connection,
  					     GB_CONTROL_TYPE_MODE_SWITCH,
  					     0, 0,
  					     GB_OPERATION_FLAG_UNIDIRECTIONAL,
  					     GFP_KERNEL);
  	if (!operation)
  		return -ENOMEM;
  
  	ret = gb_operation_request_send_sync(operation);
  	if (ret)
  		dev_err(&control->dev, "failed to send mode switch: %d\n", ret);
  
  	gb_operation_put(operation);
  
  	return ret;
  }
  
  static int gb_control_bundle_pm_status_map(u8 status)
  {
  	switch (status) {
  	case GB_CONTROL_BUNDLE_PM_INVAL:
  		return -EINVAL;
  	case GB_CONTROL_BUNDLE_PM_BUSY:
  		return -EBUSY;
  	case GB_CONTROL_BUNDLE_PM_NA:
  		return -ENOMSG;
  	case GB_CONTROL_BUNDLE_PM_FAIL:
  	default:
  		return -EREMOTEIO;
  	}
  }
  
  int gb_control_bundle_suspend(struct gb_control *control, u8 bundle_id)
  {
  	struct gb_control_bundle_pm_request request;
  	struct gb_control_bundle_pm_response response;
  	int ret;
  
  	request.bundle_id = bundle_id;
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_BUNDLE_SUSPEND, &request,
  				sizeof(request), &response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev, "failed to send bundle %u suspend: %d\n",
  			bundle_id, ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
  		dev_err(&control->dev, "failed to suspend bundle %u: %d\n",
  			bundle_id, response.status);
  		return gb_control_bundle_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  int gb_control_bundle_resume(struct gb_control *control, u8 bundle_id)
  {
  	struct gb_control_bundle_pm_request request;
  	struct gb_control_bundle_pm_response response;
  	int ret;
  
  	request.bundle_id = bundle_id;
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_BUNDLE_RESUME, &request,
  				sizeof(request), &response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev, "failed to send bundle %u resume: %d\n",
  			bundle_id, ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
  		dev_err(&control->dev, "failed to resume bundle %u: %d\n",
  			bundle_id, response.status);
  		return gb_control_bundle_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  int gb_control_bundle_deactivate(struct gb_control *control, u8 bundle_id)
  {
  	struct gb_control_bundle_pm_request request;
  	struct gb_control_bundle_pm_response response;
  	int ret;
  
  	request.bundle_id = bundle_id;
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_BUNDLE_DEACTIVATE, &request,
  				sizeof(request), &response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev,
  			"failed to send bundle %u deactivate: %d\n", bundle_id,
  			ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
  		dev_err(&control->dev, "failed to deactivate bundle %u: %d\n",
  			bundle_id, response.status);
  		return gb_control_bundle_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  int gb_control_bundle_activate(struct gb_control *control, u8 bundle_id)
  {
  	struct gb_control_bundle_pm_request request;
  	struct gb_control_bundle_pm_response response;
  	int ret;
  
  	if (!control->has_bundle_activate)
  		return 0;
  
  	request.bundle_id = bundle_id;
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_BUNDLE_ACTIVATE, &request,
  				sizeof(request), &response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev,
  			"failed to send bundle %u activate: %d\n", bundle_id,
  			ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_BUNDLE_PM_OK) {
  		dev_err(&control->dev, "failed to activate bundle %u: %d\n",
  			bundle_id, response.status);
  		return gb_control_bundle_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  static int gb_control_interface_pm_status_map(u8 status)
  {
  	switch (status) {
  	case GB_CONTROL_INTF_PM_BUSY:
  		return -EBUSY;
  	case GB_CONTROL_INTF_PM_NA:
  		return -ENOMSG;
  	default:
  		return -EREMOTEIO;
  	}
  }
  
  int gb_control_interface_suspend_prepare(struct gb_control *control)
  {
  	struct gb_control_intf_pm_response response;
  	int ret;
  
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_INTF_SUSPEND_PREPARE, NULL, 0,
  				&response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev,
  			"failed to send interface suspend prepare: %d\n", ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_INTF_PM_OK) {
  		dev_err(&control->dev, "interface error while preparing suspend: %d\n",
  			response.status);
  		return gb_control_interface_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  int gb_control_interface_deactivate_prepare(struct gb_control *control)
  {
  	struct gb_control_intf_pm_response response;
  	int ret;
  
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_INTF_DEACTIVATE_PREPARE, NULL,
  				0, &response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev, "failed to send interface deactivate prepare: %d\n",
  			ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_INTF_PM_OK) {
  		dev_err(&control->dev, "interface error while preparing deactivate: %d\n",
  			response.status);
  		return gb_control_interface_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  int gb_control_interface_hibernate_abort(struct gb_control *control)
  {
  	struct gb_control_intf_pm_response response;
  	int ret;
  
  	ret = gb_operation_sync(control->connection,
  				GB_CONTROL_TYPE_INTF_HIBERNATE_ABORT, NULL, 0,
  				&response, sizeof(response));
  	if (ret) {
  		dev_err(&control->dev,
  			"failed to send interface aborting hibernate: %d\n",
  			ret);
  		return ret;
  	}
  
  	if (response.status != GB_CONTROL_INTF_PM_OK) {
  		dev_err(&control->dev, "interface error while aborting hibernate: %d\n",
  			response.status);
  		return gb_control_interface_pm_status_map(response.status);
  	}
  
  	return 0;
  }
  
  static ssize_t vendor_string_show(struct device *dev,
  				  struct device_attribute *attr, char *buf)
  {
  	struct gb_control *control = to_gb_control(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%s\n", control->vendor_string);
  }
  static DEVICE_ATTR_RO(vendor_string);
  
  static ssize_t product_string_show(struct device *dev,
  				   struct device_attribute *attr, char *buf)
  {
  	struct gb_control *control = to_gb_control(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%s\n", control->product_string);
  }
  static DEVICE_ATTR_RO(product_string);
  
  static struct attribute *control_attrs[] = {
  	&dev_attr_vendor_string.attr,
  	&dev_attr_product_string.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(control);
  
  static void gb_control_release(struct device *dev)
  {
  	struct gb_control *control = to_gb_control(dev);
  
  	gb_connection_destroy(control->connection);
  
  	kfree(control->vendor_string);
  	kfree(control->product_string);
  
  	kfree(control);
  }
  
  struct device_type greybus_control_type = {
  	.name =		"greybus_control",
  	.release =	gb_control_release,
  };
  
  struct gb_control *gb_control_create(struct gb_interface *intf)
  {
  	struct gb_connection *connection;
  	struct gb_control *control;
  
  	control = kzalloc(sizeof(*control), GFP_KERNEL);
  	if (!control)
  		return ERR_PTR(-ENOMEM);
  
  	control->intf = intf;
  
  	connection = gb_connection_create_control(intf);
  	if (IS_ERR(connection)) {
  		dev_err(&intf->dev,
  			"failed to create control connection: %ld\n",
  			PTR_ERR(connection));
  		kfree(control);
  		return ERR_CAST(connection);
  	}
  
  	control->connection = connection;
  
  	control->dev.parent = &intf->dev;
  	control->dev.bus = &greybus_bus_type;
  	control->dev.type = &greybus_control_type;
  	control->dev.groups = control_groups;
  	control->dev.dma_mask = intf->dev.dma_mask;
  	device_initialize(&control->dev);
  	dev_set_name(&control->dev, "%s.ctrl", dev_name(&intf->dev));
  
  	gb_connection_set_data(control->connection, control);
  
  	return control;
  }
  
  int gb_control_enable(struct gb_control *control)
  {
  	int ret;
  
  	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
  
  	ret = gb_connection_enable_tx(control->connection);
  	if (ret) {
  		dev_err(&control->connection->intf->dev,
  			"failed to enable control connection: %d\n",
  			ret);
  		return ret;
  	}
  
  	ret = gb_control_get_version(control);
  	if (ret)
  		goto err_disable_connection;
  
  	if (control->protocol_major > 0 || control->protocol_minor > 1)
  		control->has_bundle_version = true;
  
  	/* FIXME: use protocol version instead */
  	if (!(control->intf->quirks & GB_INTERFACE_QUIRK_NO_BUNDLE_ACTIVATE))
  		control->has_bundle_activate = true;
  
  	return 0;
  
  err_disable_connection:
  	gb_connection_disable(control->connection);
  
  	return ret;
  }
  
  void gb_control_disable(struct gb_control *control)
  {
  	dev_dbg(&control->connection->intf->dev, "%s\n", __func__);
  
  	if (control->intf->disconnected)
  		gb_connection_disable_forced(control->connection);
  	else
  		gb_connection_disable(control->connection);
  }
  
  int gb_control_suspend(struct gb_control *control)
  {
  	gb_connection_disable(control->connection);
  
  	return 0;
  }
  
  int gb_control_resume(struct gb_control *control)
  {
  	int ret;
  
  	ret = gb_connection_enable_tx(control->connection);
  	if (ret) {
  		dev_err(&control->connection->intf->dev,
  			"failed to enable control connection: %d\n", ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  int gb_control_add(struct gb_control *control)
  {
  	int ret;
  
  	ret = device_add(&control->dev);
  	if (ret) {
  		dev_err(&control->dev,
  			"failed to register control device: %d\n",
  			ret);
  		return ret;
  	}
  
  	return 0;
  }
  
  void gb_control_del(struct gb_control *control)
  {
  	if (device_is_registered(&control->dev))
  		device_del(&control->dev);
  }
  
  struct gb_control *gb_control_get(struct gb_control *control)
  {
  	get_device(&control->dev);
  
  	return control;
  }
  
  void gb_control_put(struct gb_control *control)
  {
  	put_device(&control->dev);
  }
  
  void gb_control_mode_switch_prepare(struct gb_control *control)
  {
  	gb_connection_mode_switch_prepare(control->connection);
  }
  
  void gb_control_mode_switch_complete(struct gb_control *control)
  {
  	gb_connection_mode_switch_complete(control->connection);
  }
  