// SPDX-License-Identifier: GPL-2.0

  /*
   * Greybus Host Device
   *
   * Copyright 2014-2015 Google Inc.
   * Copyright 2014-2015 Linaro Ltd.

   */

  #include <linux/kernel.h>
  #include <linux/slab.h>

  #include <linux/greybus.h>

  #include "greybus_trace.h"

  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_create);
  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_release);
  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_add);
  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_del);

  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_hd_in);

  EXPORT_TRACEPOINT_SYMBOL_GPL(gb_message_submit);

  static struct ida gb_hd_bus_id_map;

  int gb_hd_output(struct gb_host_device *hd, void *req, u16 size, u8 cmd,
  		 bool async)
  {
  	if (!hd || !hd->driver || !hd->driver->output)
  		return -EINVAL;
  	return hd->driver->output(hd, req, size, cmd, async);
  }
  EXPORT_SYMBOL_GPL(gb_hd_output);

  static ssize_t bus_id_show(struct device *dev,

  			   struct device_attribute *attr, char *buf)

  {
  	struct gb_host_device *hd = to_gb_host_device(dev);
  
  	return sprintf(buf, "%d
  ", hd->bus_id);
  }
  static DEVICE_ATTR_RO(bus_id);
  
  static struct attribute *bus_attrs[] = {
  	&dev_attr_bus_id.attr,
  	NULL
  };
  ATTRIBUTE_GROUPS(bus);

  int gb_hd_cport_reserve(struct gb_host_device *hd, u16 cport_id)
  {
  	struct ida *id_map = &hd->cport_id_map;
  	int ret;
  
  	ret = ida_simple_get(id_map, cport_id, cport_id + 1, GFP_KERNEL);
  	if (ret < 0) {
  		dev_err(&hd->dev, "failed to reserve cport %u
  ", cport_id);
  		return ret;
  	}
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(gb_hd_cport_reserve);

  void gb_hd_cport_release_reserved(struct gb_host_device *hd, u16 cport_id)
  {
  	struct ida *id_map = &hd->cport_id_map;
  
  	ida_simple_remove(id_map, cport_id);
  }
  EXPORT_SYMBOL_GPL(gb_hd_cport_release_reserved);

  /* Locking: Caller guarantees serialisation */

  int gb_hd_cport_allocate(struct gb_host_device *hd, int cport_id,

  			 unsigned long flags)

  {
  	struct ida *id_map = &hd->cport_id_map;
  	int ida_start, ida_end;

  	if (hd->driver->cport_allocate)
  		return hd->driver->cport_allocate(hd, cport_id, flags);

  	if (cport_id < 0) {
  		ida_start = 0;
  		ida_end = hd->num_cports;
  	} else if (cport_id < hd->num_cports) {
  		ida_start = cport_id;
  		ida_end = cport_id + 1;
  	} else {
  		dev_err(&hd->dev, "cport %d not available
  ", cport_id);
  		return -EINVAL;
  	}
  
  	return ida_simple_get(id_map, ida_start, ida_end, GFP_KERNEL);
  }
  
  /* Locking: Caller guarantees serialisation */
  void gb_hd_cport_release(struct gb_host_device *hd, u16 cport_id)
  {

  	if (hd->driver->cport_release) {
  		hd->driver->cport_release(hd, cport_id);
  		return;
  	}

  	ida_simple_remove(&hd->cport_id_map, cport_id);
  }

  static void gb_hd_release(struct device *dev)

  {

  	struct gb_host_device *hd = to_gb_host_device(dev);

  	trace_gb_hd_release(hd);

  	if (hd->svc)
  		gb_svc_put(hd->svc);

  	ida_simple_remove(&gb_hd_bus_id_map, hd->bus_id);

  	ida_destroy(&hd->cport_id_map);
  	kfree(hd);

  }

  struct device_type greybus_hd_type = {
  	.name		= "greybus_host_device",
  	.release	= gb_hd_release,
  };

  struct gb_host_device *gb_hd_create(struct gb_hd_driver *driver,

  				    struct device *parent,
  				    size_t buffer_size_max,
  				    size_t num_cports)

  {

  	struct gb_host_device *hd;

  	int ret;

  
  	/*
  	 * Validate that the driver implements all of the callbacks
  	 * so that we don't have to every time we make them.
  	 */
  	if ((!driver->message_send) || (!driver->message_cancel)) {

  		dev_err(parent, "mandatory hd-callbacks missing
  ");

  		return ERR_PTR(-EINVAL);
  	}
  
  	if (buffer_size_max < GB_OPERATION_MESSAGE_SIZE_MIN) {
  		dev_err(parent, "greybus host-device buffers too small
  ");
  		return ERR_PTR(-EINVAL);
  	}

  	if (num_cports == 0 || num_cports > CPORT_ID_MAX + 1) {

  		dev_err(parent, "Invalid number of CPorts: %zu
  ", num_cports);
  		return ERR_PTR(-EINVAL);
  	}
  
  	/*
  	 * Make sure to never allocate messages larger than what the Greybus
  	 * protocol supports.
  	 */
  	if (buffer_size_max > GB_OPERATION_MESSAGE_SIZE_MAX) {
  		dev_warn(parent, "limiting buffer size to %u
  ",
  			 GB_OPERATION_MESSAGE_SIZE_MAX);
  		buffer_size_max = GB_OPERATION_MESSAGE_SIZE_MAX;
  	}
  
  	hd = kzalloc(sizeof(*hd) + driver->hd_priv_size, GFP_KERNEL);
  	if (!hd)
  		return ERR_PTR(-ENOMEM);

  	ret = ida_simple_get(&gb_hd_bus_id_map, 1, 0, GFP_KERNEL);
  	if (ret < 0) {
  		kfree(hd);
  		return ERR_PTR(ret);
  	}

  	hd->bus_id = ret;

  	hd->driver = driver;

  	INIT_LIST_HEAD(&hd->modules);

  	INIT_LIST_HEAD(&hd->connections);
  	ida_init(&hd->cport_id_map);
  	hd->buffer_size_max = buffer_size_max;
  	hd->num_cports = num_cports;

  	hd->dev.parent = parent;
  	hd->dev.bus = &greybus_bus_type;
  	hd->dev.type = &greybus_hd_type;

  	hd->dev.groups = bus_groups;

  	hd->dev.dma_mask = hd->dev.parent->dma_mask;
  	device_initialize(&hd->dev);
  	dev_set_name(&hd->dev, "greybus%d", hd->bus_id);

  	trace_gb_hd_create(hd);

  	hd->svc = gb_svc_create(hd);
  	if (!hd->svc) {
  		dev_err(&hd->dev, "failed to create svc
  ");

  		put_device(&hd->dev);
  		return ERR_PTR(-ENOMEM);

  	}

  	return hd;

  }

  EXPORT_SYMBOL_GPL(gb_hd_create);

  int gb_hd_add(struct gb_host_device *hd)
  {

  	int ret;
  
  	ret = device_add(&hd->dev);
  	if (ret)
  		return ret;

  	ret = gb_svc_add(hd->svc);

  	if (ret) {

  		device_del(&hd->dev);
  		return ret;
  	}

  	trace_gb_hd_add(hd);

  	return 0;

  }

  EXPORT_SYMBOL_GPL(gb_hd_add);

  void gb_hd_del(struct gb_host_device *hd)

  {

  	trace_gb_hd_del(hd);

  	/*
  	 * Tear down the svc and flush any on-going hotplug processing before
  	 * removing the remaining interfaces.
  	 */

  	gb_svc_del(hd->svc);

  
  	device_del(&hd->dev);

  }
  EXPORT_SYMBOL_GPL(gb_hd_del);

  void gb_hd_shutdown(struct gb_host_device *hd)
  {
  	gb_svc_del(hd->svc);
  }
  EXPORT_SYMBOL_GPL(gb_hd_shutdown);

  void gb_hd_put(struct gb_host_device *hd)
  {

  	put_device(&hd->dev);

  }

  EXPORT_SYMBOL_GPL(gb_hd_put);

  
  int __init gb_hd_init(void)
  {
  	ida_init(&gb_hd_bus_id_map);
  
  	return 0;
  }
  
  void gb_hd_exit(void)
  {
  	ida_destroy(&gb_hd_bus_id_map);
  }