/* Copyright (c) 2012, The Linux Foundation. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 and
   * only version 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/types.h>
  #include <linux/device.h>
  #include <linux/io.h>
  #include <linux/err.h>
  #include <linux/export.h>
  #include <linux/slab.h>
  #include <linux/mutex.h>
  #include <linux/clk.h>
  #include <linux/coresight.h>
  #include <linux/of_platform.h>
  #include <linux/delay.h>
  
  #include "coresight-priv.h"
  
  static DEFINE_MUTEX(coresight_mutex);
  
  static int coresight_id_match(struct device *dev, void *data)
  {
  	int trace_id, i_trace_id;
  	struct coresight_device *csdev, *i_csdev;
  
  	csdev = data;
  	i_csdev = to_coresight_device(dev);
  
  	/*
  	 * No need to care about oneself and components that are not
  	 * sources or not enabled
  	 */
  	if (i_csdev == csdev || !i_csdev->enable ||
  	    i_csdev->type != CORESIGHT_DEV_TYPE_SOURCE)
  		return 0;
  
  	/* Get the source ID for both compoment */
  	trace_id = source_ops(csdev)->trace_id(csdev);
  	i_trace_id = source_ops(i_csdev)->trace_id(i_csdev);
  
  	/* All you need is one */
  	if (trace_id == i_trace_id)
  		return 1;
  
  	return 0;
  }
  
  static int coresight_source_is_unique(struct coresight_device *csdev)
  {
  	int trace_id = source_ops(csdev)->trace_id(csdev);
  
  	/* this shouldn't happen */
  	if (trace_id < 0)
  		return 0;
  
  	return !bus_for_each_dev(&coresight_bustype, NULL,
  				 csdev, coresight_id_match);
  }
  
  static int coresight_find_link_inport(struct coresight_device *csdev)
  {
  	int i;
  	struct coresight_device *parent;
  	struct coresight_connection *conn;
  
  	parent = container_of(csdev->path_link.next,
  			      struct coresight_device, path_link);
  
  	for (i = 0; i < parent->nr_outport; i++) {
  		conn = &parent->conns[i];
  		if (conn->child_dev == csdev)
  			return conn->child_port;
  	}
  
  	dev_err(&csdev->dev, "couldn't find inport, parent: %s, child: %s
  ",
  		dev_name(&parent->dev), dev_name(&csdev->dev));
  
  	return 0;
  }
  
  static int coresight_find_link_outport(struct coresight_device *csdev)
  {
  	int i;
  	struct coresight_device *child;
  	struct coresight_connection *conn;
  
  	child = container_of(csdev->path_link.prev,
  			     struct coresight_device, path_link);
  
  	for (i = 0; i < csdev->nr_outport; i++) {
  		conn = &csdev->conns[i];
  		if (conn->child_dev == child)
  			return conn->outport;
  	}
  
  	dev_err(&csdev->dev, "couldn't find outport, parent: %s, child: %s
  ",
  		dev_name(&csdev->dev), dev_name(&child->dev));
  
  	return 0;
  }
  
  static int coresight_enable_sink(struct coresight_device *csdev)
  {
  	int ret;
  
  	if (!csdev->enable) {
  		if (sink_ops(csdev)->enable) {
  			ret = sink_ops(csdev)->enable(csdev);
  			if (ret)
  				return ret;
  		}
  		csdev->enable = true;
  	}
  
  	atomic_inc(csdev->refcnt);
  
  	return 0;
  }
  
  static void coresight_disable_sink(struct coresight_device *csdev)
  {
  	if (atomic_dec_return(csdev->refcnt) == 0) {
  		if (sink_ops(csdev)->disable) {
  			sink_ops(csdev)->disable(csdev);
  			csdev->enable = false;
  		}
  	}
  }
  
  static int coresight_enable_link(struct coresight_device *csdev)
  {
  	int ret;
  	int link_subtype;
  	int refport, inport, outport;
  
  	inport = coresight_find_link_inport(csdev);
  	outport = coresight_find_link_outport(csdev);
  	link_subtype = csdev->subtype.link_subtype;
  
  	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
  		refport = inport;
  	else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
  		refport = outport;
  	else
  		refport = 0;
  
  	if (atomic_inc_return(&csdev->refcnt[refport]) == 1) {
  		if (link_ops(csdev)->enable) {
  			ret = link_ops(csdev)->enable(csdev, inport, outport);
  			if (ret)
  				return ret;
  		}
  	}
  
  	csdev->enable = true;
  
  	return 0;
  }
  
  static void coresight_disable_link(struct coresight_device *csdev)
  {
  	int i, nr_conns;
  	int link_subtype;
  	int refport, inport, outport;
  
  	inport = coresight_find_link_inport(csdev);
  	outport = coresight_find_link_outport(csdev);
  	link_subtype = csdev->subtype.link_subtype;
  
  	if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG) {
  		refport = inport;
  		nr_conns = csdev->nr_inport;
  	} else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT) {
  		refport = outport;
  		nr_conns = csdev->nr_outport;
  	} else {
  		refport = 0;
  		nr_conns = 1;
  	}
  
  	if (atomic_dec_return(&csdev->refcnt[refport]) == 0) {
  		if (link_ops(csdev)->disable)
  			link_ops(csdev)->disable(csdev, inport, outport);
  	}
  
  	for (i = 0; i < nr_conns; i++)
  		if (atomic_read(&csdev->refcnt[i]) != 0)
  			return;
  
  	csdev->enable = false;
  }
  
  static int coresight_enable_source(struct coresight_device *csdev)
  {
  	int ret;
  
  	if (!coresight_source_is_unique(csdev)) {
  		dev_warn(&csdev->dev, "traceID %d not unique
  ",
  			 source_ops(csdev)->trace_id(csdev));
  		return -EINVAL;
  	}
  
  	if (!csdev->enable) {
  		if (source_ops(csdev)->enable) {
  			ret = source_ops(csdev)->enable(csdev);
  			if (ret)
  				return ret;
  		}
  		csdev->enable = true;
  	}
  
  	atomic_inc(csdev->refcnt);
  
  	return 0;
  }
  
  static void coresight_disable_source(struct coresight_device *csdev)
  {
  	if (atomic_dec_return(csdev->refcnt) == 0) {
  		if (source_ops(csdev)->disable) {
  			source_ops(csdev)->disable(csdev);
  			csdev->enable = false;
  		}
  	}
  }
  
  static int coresight_enable_path(struct list_head *path)
  {
  	int ret = 0;
  	struct coresight_device *cd;
  
  	/*
  	 * At this point we have a full @path, from source to sink.  The
  	 * sink is the first entry and the source the last one.  Go through
  	 * all the components and enable them one by one.
  	 */
  	list_for_each_entry(cd, path, path_link) {
  		if (cd == list_first_entry(path, struct coresight_device,
  					   path_link)) {
  			ret = coresight_enable_sink(cd);
  		} else if (list_is_last(&cd->path_link, path)) {
  			/*
  			 * Don't enable the source just yet - this needs to
  			 * happen at the very end when all links and sink
  			 * along the path have been configured properly.
  			 */
  			;
  		} else {
  			ret = coresight_enable_link(cd);
  		}
  		if (ret)
  			goto err;
  	}
  
  	return 0;
  err:
  	list_for_each_entry_continue_reverse(cd, path, path_link) {
  		if (cd == list_first_entry(path, struct coresight_device,
  					   path_link)) {
  			coresight_disable_sink(cd);
  		} else if (list_is_last(&cd->path_link, path)) {
  			;
  		} else {
  			coresight_disable_link(cd);
  		}
  	}
  
  	return ret;
  }
  
  static int coresight_disable_path(struct list_head *path)
  {
  	struct coresight_device *cd;
  
  	list_for_each_entry_reverse(cd, path, path_link) {
  		if (cd == list_first_entry(path, struct coresight_device,
  					   path_link)) {
  			coresight_disable_sink(cd);
  		} else if (list_is_last(&cd->path_link, path)) {
  			/*
  			 * The source has already been stopped, no need
  			 * to do it again here.
  			 */
  			;
  		} else {
  			coresight_disable_link(cd);
  		}
  	}
  
  	return 0;
  }
  
  static int coresight_build_paths(struct coresight_device *csdev,
  				 struct list_head *path,
  				 bool enable)
  {
  	int i, ret = -EINVAL;
  	struct coresight_connection *conn;
  
  	list_add(&csdev->path_link, path);
  
  	if ((csdev->type == CORESIGHT_DEV_TYPE_SINK ||
  	    csdev->type == CORESIGHT_DEV_TYPE_LINKSINK) &&
  	    csdev->activated) {
  		if (enable)
  			ret = coresight_enable_path(path);
  		else
  			ret = coresight_disable_path(path);
  	} else {
  		for (i = 0; i < csdev->nr_outport; i++) {
  			conn = &csdev->conns[i];
  			if (coresight_build_paths(conn->child_dev,
  						    path, enable) == 0)
  				ret = 0;
  		}
  	}
  
  	if (list_first_entry(path, struct coresight_device, path_link) != csdev)
  		dev_err(&csdev->dev, "wrong device in %s
  ", __func__);
  
  	list_del(&csdev->path_link);
  
  	return ret;
  }
  
  int coresight_enable(struct coresight_device *csdev)
  {
  	int ret = 0;
  	LIST_HEAD(path);
  
  	mutex_lock(&coresight_mutex);
  	if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
  		ret = -EINVAL;
  		dev_err(&csdev->dev, "wrong device type in %s
  ", __func__);
  		goto out;
  	}
  	if (csdev->enable)
  		goto out;
  
  	if (coresight_build_paths(csdev, &path, true)) {
  		dev_err(&csdev->dev, "building path(s) failed
  ");
  		goto out;
  	}
  
  	if (coresight_enable_source(csdev))
  		dev_err(&csdev->dev, "source enable failed
  ");
  out:
  	mutex_unlock(&coresight_mutex);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(coresight_enable);
  
  void coresight_disable(struct coresight_device *csdev)
  {
  	LIST_HEAD(path);
  
  	mutex_lock(&coresight_mutex);
  	if (csdev->type != CORESIGHT_DEV_TYPE_SOURCE) {
  		dev_err(&csdev->dev, "wrong device type in %s
  ", __func__);
  		goto out;
  	}
  	if (!csdev->enable)
  		goto out;
  
  	coresight_disable_source(csdev);
  	if (coresight_build_paths(csdev, &path, false))
  		dev_err(&csdev->dev, "releasing path(s) failed
  ");
  
  out:
  	mutex_unlock(&coresight_mutex);
  }
  EXPORT_SYMBOL_GPL(coresight_disable);
  
  static ssize_t enable_sink_show(struct device *dev,
  				struct device_attribute *attr, char *buf)
  {
  	struct coresight_device *csdev = to_coresight_device(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%u
  ", (unsigned)csdev->activated);
  }
  
  static ssize_t enable_sink_store(struct device *dev,
  				 struct device_attribute *attr,
  				 const char *buf, size_t size)
  {
  	int ret;
  	unsigned long val;
  	struct coresight_device *csdev = to_coresight_device(dev);
  
  	ret = kstrtoul(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	if (val)
  		csdev->activated = true;
  	else
  		csdev->activated = false;
  
  	return size;
  
  }
  static DEVICE_ATTR_RW(enable_sink);
  
  static ssize_t enable_source_show(struct device *dev,
  				  struct device_attribute *attr, char *buf)
  {
  	struct coresight_device *csdev = to_coresight_device(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%u
  ", (unsigned)csdev->enable);
  }
  
  static ssize_t enable_source_store(struct device *dev,
  				   struct device_attribute *attr,
  				   const char *buf, size_t size)
  {
  	int ret = 0;
  	unsigned long val;
  	struct coresight_device *csdev = to_coresight_device(dev);
  
  	ret = kstrtoul(buf, 10, &val);
  	if (ret)
  		return ret;
  
  	if (val) {
  		ret = coresight_enable(csdev);
  		if (ret)
  			return ret;
  	} else {
  		coresight_disable(csdev);
  	}
  
  	return size;
  }
  static DEVICE_ATTR_RW(enable_source);
  
  static struct attribute *coresight_sink_attrs[] = {
  	&dev_attr_enable_sink.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(coresight_sink);
  
  static struct attribute *coresight_source_attrs[] = {
  	&dev_attr_enable_source.attr,
  	NULL,
  };
  ATTRIBUTE_GROUPS(coresight_source);
  
  static struct device_type coresight_dev_type[] = {
  	{
  		.name = "none",
  	},
  	{
  		.name = "sink",
  		.groups = coresight_sink_groups,
  	},
  	{
  		.name = "link",
  	},
  	{
  		.name = "linksink",
  		.groups = coresight_sink_groups,
  	},
  	{
  		.name = "source",
  		.groups = coresight_source_groups,
  	},
  };
  
  static void coresight_device_release(struct device *dev)
  {
  	struct coresight_device *csdev = to_coresight_device(dev);
  
  	kfree(csdev);
  }
  
  static int coresight_orphan_match(struct device *dev, void *data)
  {
  	int i;
  	bool still_orphan = false;
  	struct coresight_device *csdev, *i_csdev;
  	struct coresight_connection *conn;
  
  	csdev = data;
  	i_csdev = to_coresight_device(dev);
  
  	/* No need to check oneself */
  	if (csdev == i_csdev)
  		return 0;
  
  	/* Move on to another component if no connection is orphan */
  	if (!i_csdev->orphan)
  		return 0;
  	/*
  	 * Circle throuch all the connection of that component.  If we find
  	 * an orphan connection whose name matches @csdev, link it.
  	 */
  	for (i = 0; i < i_csdev->nr_outport; i++) {
  		conn = &i_csdev->conns[i];
  
  		/* We have found at least one orphan connection */
  		if (conn->child_dev == NULL) {
  			/* Does it match this newly added device? */
  			if (!strcmp(dev_name(&csdev->dev), conn->child_name)) {
  				conn->child_dev = csdev;
  			} else {
  				/* This component still has an orphan */
  				still_orphan = true;
  			}
  		}
  	}
  
  	i_csdev->orphan = still_orphan;
  
  	/*
  	 * Returning '0' ensures that all known component on the
  	 * bus will be checked.
  	 */
  	return 0;
  }
  
  static void coresight_fixup_orphan_conns(struct coresight_device *csdev)
  {
  	/*
  	 * No need to check for a return value as orphan connection(s)
  	 * are hooked-up with each newly added component.
  	 */
  	bus_for_each_dev(&coresight_bustype, NULL,
  				 csdev, coresight_orphan_match);
  }
  
  
  static int coresight_name_match(struct device *dev, void *data)
  {
  	char *to_match;
  	struct coresight_device *i_csdev;
  
  	to_match = data;
  	i_csdev = to_coresight_device(dev);
  
  	if (to_match && !strcmp(to_match, dev_name(&i_csdev->dev)))
  		return 1;
  
  	return 0;
  }
  
  static void coresight_fixup_device_conns(struct coresight_device *csdev)
  {
  	int i;
  	struct device *dev = NULL;
  	struct coresight_connection *conn;
  
  	for (i = 0; i < csdev->nr_outport; i++) {
  		conn = &csdev->conns[i];
  		dev = bus_find_device(&coresight_bustype, NULL,
  				      (void *)conn->child_name,
  				      coresight_name_match);
  
  		if (dev) {
  			conn->child_dev = to_coresight_device(dev);
  		} else {
  			csdev->orphan = true;
  			conn->child_dev = NULL;
  		}
  	}
  }
  
  /**
   * coresight_timeout - loop until a bit has changed to a specific state.
   * @addr: base address of the area of interest.
   * @offset: address of a register, starting from @addr.
   * @position: the position of the bit of interest.
   * @value: the value the bit should have.
   *
   * Return: 0 as soon as the bit has taken the desired state or -EAGAIN if
   * TIMEOUT_US has elapsed, which ever happens first.
   */
  
  int coresight_timeout(void __iomem *addr, u32 offset, int position, int value)
  {
  	int i;
  	u32 val;
  
  	for (i = TIMEOUT_US; i > 0; i--) {
  		val = __raw_readl(addr + offset);
  		/* waiting on the bit to go from 0 to 1 */
  		if (value) {
  			if (val & BIT(position))
  				return 0;
  		/* waiting on the bit to go from 1 to 0 */
  		} else {
  			if (!(val & BIT(position)))
  				return 0;
  		}
  
  		/*
  		 * Delay is arbitrary - the specification doesn't say how long
  		 * we are expected to wait.  Extra check required to make sure
  		 * we don't wait needlessly on the last iteration.
  		 */
  		if (i - 1)
  			udelay(1);
  	}
  
  	return -EAGAIN;
  }
  
  struct bus_type coresight_bustype = {
  	.name	= "coresight",
  };
  
  static int __init coresight_init(void)
  {
  	return bus_register(&coresight_bustype);
  }
  postcore_initcall(coresight_init);
  
  struct coresight_device *coresight_register(struct coresight_desc *desc)
  {
  	int i;
  	int ret;
  	int link_subtype;
  	int nr_refcnts = 1;
  	atomic_t *refcnts = NULL;
  	struct coresight_device *csdev;
  	struct coresight_connection *conns;
  
  	csdev = kzalloc(sizeof(*csdev), GFP_KERNEL);
  	if (!csdev) {
  		ret = -ENOMEM;
  		goto err_kzalloc_csdev;
  	}
  
  	if (desc->type == CORESIGHT_DEV_TYPE_LINK ||
  	    desc->type == CORESIGHT_DEV_TYPE_LINKSINK) {
  		link_subtype = desc->subtype.link_subtype;
  
  		if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_MERG)
  			nr_refcnts = desc->pdata->nr_inport;
  		else if (link_subtype == CORESIGHT_DEV_SUBTYPE_LINK_SPLIT)
  			nr_refcnts = desc->pdata->nr_outport;
  	}
  
  	refcnts = kcalloc(nr_refcnts, sizeof(*refcnts), GFP_KERNEL);
  	if (!refcnts) {
  		ret = -ENOMEM;
  		goto err_kzalloc_refcnts;
  	}
  
  	csdev->refcnt = refcnts;
  
  	csdev->nr_inport = desc->pdata->nr_inport;
  	csdev->nr_outport = desc->pdata->nr_outport;
  	conns = kcalloc(csdev->nr_outport, sizeof(*conns), GFP_KERNEL);
  	if (!conns) {
  		ret = -ENOMEM;
  		goto err_kzalloc_conns;
  	}
  
  	for (i = 0; i < csdev->nr_outport; i++) {
  		conns[i].outport = desc->pdata->outports[i];
  		conns[i].child_name = desc->pdata->child_names[i];
  		conns[i].child_port = desc->pdata->child_ports[i];
  	}
  
  	csdev->conns = conns;
  
  	csdev->type = desc->type;
  	csdev->subtype = desc->subtype;
  	csdev->ops = desc->ops;
  	csdev->orphan = false;
  
  	csdev->dev.type = &coresight_dev_type[desc->type];
  	csdev->dev.groups = desc->groups;
  	csdev->dev.parent = desc->dev;
  	csdev->dev.release = coresight_device_release;
  	csdev->dev.bus = &coresight_bustype;
  	dev_set_name(&csdev->dev, "%s", desc->pdata->name);
  
  	ret = device_register(&csdev->dev);
  	if (ret)
  		goto err_device_register;
  
  	mutex_lock(&coresight_mutex);
  
  	coresight_fixup_device_conns(csdev);
  	coresight_fixup_orphan_conns(csdev);
  
  	mutex_unlock(&coresight_mutex);
  
  	return csdev;
  
  err_device_register:
  	kfree(conns);
  err_kzalloc_conns:
  	kfree(refcnts);
  err_kzalloc_refcnts:
  	kfree(csdev);
  err_kzalloc_csdev:
  	return ERR_PTR(ret);
  }
  EXPORT_SYMBOL_GPL(coresight_register);
  
  void coresight_unregister(struct coresight_device *csdev)
  {
  	mutex_lock(&coresight_mutex);
  
  	kfree(csdev->conns);
  	device_unregister(&csdev->dev);
  
  	mutex_unlock(&coresight_mutex);
  }
  EXPORT_SYMBOL_GPL(coresight_unregister);
  
  MODULE_LICENSE("GPL v2");