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- /*
- * Componentized device handling.
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This is work in progress. We gather up the component devices into a list,
- * and bind them when instructed. At the moment, we're specific to the DRM
- * subsystem, and only handles one master device, but this doesn't have to be
- * the case.
- */
- #include <linux/component.h>
- #include <linux/device.h>
- #include <linux/kref.h>
- #include <linux/list.h>
- #include <linux/module.h>
- #include <linux/mutex.h>
- #include <linux/slab.h>
- struct component_match {
- size_t alloc;
- size_t num;
- struct {
- void *data;
- int (*fn)(struct device *, void *);
- } compare[0];
- };
- struct master {
- struct list_head node;
- struct list_head components;
- bool bound;
- const struct component_master_ops *ops;
- struct device *dev;
- struct component_match *match;
- };
- struct component {
- struct list_head node;
- struct list_head master_node;
- struct master *master;
- bool bound;
- const struct component_ops *ops;
- struct device *dev;
- };
- static DEFINE_MUTEX(component_mutex);
- static LIST_HEAD(component_list);
- static LIST_HEAD(masters);
- static struct master *__master_find(struct device *dev,
- const struct component_master_ops *ops)
- {
- struct master *m;
- list_for_each_entry(m, &masters, node)
- if (m->dev == dev && (!ops || m->ops == ops))
- return m;
- return NULL;
- }
- /* Attach an unattached component to a master. */
- static void component_attach_master(struct master *master, struct component *c)
- {
- c->master = master;
- list_add_tail(&c->master_node, &master->components);
- }
- /* Detach a component from a master. */
- static void component_detach_master(struct master *master, struct component *c)
- {
- list_del(&c->master_node);
- c->master = NULL;
- }
- /*
- * Add a component to a master, finding the component via the compare
- * function and compare data. This is safe to call for duplicate matches
- * and will not result in the same component being added multiple times.
- */
- int component_master_add_child(struct master *master,
- int (*compare)(struct device *, void *), void *compare_data)
- {
- struct component *c;
- int ret = -ENXIO;
- list_for_each_entry(c, &component_list, node) {
- if (c->master && c->master != master)
- continue;
- if (compare(c->dev, compare_data)) {
- if (!c->master)
- component_attach_master(master, c);
- ret = 0;
- break;
- }
- }
- return ret;
- }
- EXPORT_SYMBOL_GPL(component_master_add_child);
- static int find_components(struct master *master)
- {
- struct component_match *match = master->match;
- size_t i;
- int ret = 0;
- if (!match) {
- /*
- * Search the list of components, looking for components that
- * belong to this master, and attach them to the master.
- */
- return master->ops->add_components(master->dev, master);
- }
- /*
- * Scan the array of match functions and attach
- * any components which are found to this master.
- */
- for (i = 0; i < match->num; i++) {
- ret = component_master_add_child(master,
- match->compare[i].fn,
- match->compare[i].data);
- if (ret)
- break;
- }
- return ret;
- }
- /* Detach all attached components from this master */
- static void master_remove_components(struct master *master)
- {
- while (!list_empty(&master->components)) {
- struct component *c = list_first_entry(&master->components,
- struct component, master_node);
- WARN_ON(c->master != master);
- component_detach_master(master, c);
- }
- }
- /*
- * Try to bring up a master. If component is NULL, we're interested in
- * this master, otherwise it's a component which must be present to try
- * and bring up the master.
- *
- * Returns 1 for successful bringup, 0 if not ready, or -ve errno.
- */
- static int try_to_bring_up_master(struct master *master,
- struct component *component)
- {
- int ret;
- if (master->bound)
- return 0;
- /*
- * Search the list of components, looking for components that
- * belong to this master, and attach them to the master.
- */
- if (find_components(master)) {
- /* Failed to find all components */
- ret = 0;
- goto out;
- }
- if (component && component->master != master) {
- ret = 0;
- goto out;
- }
- if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) {
- ret = -ENOMEM;
- goto out;
- }
- /* Found all components */
- ret = master->ops->bind(master->dev);
- if (ret < 0) {
- devres_release_group(master->dev, NULL);
- dev_info(master->dev, "master bind failed: %d\n", ret);
- goto out;
- }
- master->bound = true;
- return 1;
- out:
- master_remove_components(master);
- return ret;
- }
- static int try_to_bring_up_masters(struct component *component)
- {
- struct master *m;
- int ret = 0;
- list_for_each_entry(m, &masters, node) {
- ret = try_to_bring_up_master(m, component);
- if (ret != 0)
- break;
- }
- return ret;
- }
- static void take_down_master(struct master *master)
- {
- if (master->bound) {
- master->ops->unbind(master->dev);
- devres_release_group(master->dev, NULL);
- master->bound = false;
- }
- master_remove_components(master);
- }
- static size_t component_match_size(size_t num)
- {
- return offsetof(struct component_match, compare[num]);
- }
- static struct component_match *component_match_realloc(struct device *dev,
- struct component_match *match, size_t num)
- {
- struct component_match *new;
- if (match && match->alloc == num)
- return match;
- new = devm_kmalloc(dev, component_match_size(num), GFP_KERNEL);
- if (!new)
- return ERR_PTR(-ENOMEM);
- if (match) {
- memcpy(new, match, component_match_size(min(match->num, num)));
- devm_kfree(dev, match);
- } else {
- new->num = 0;
- }
- new->alloc = num;
- return new;
- }
- /*
- * Add a component to be matched.
- *
- * The match array is first created or extended if necessary.
- */
- void component_match_add(struct device *dev, struct component_match **matchptr,
- int (*compare)(struct device *, void *), void *compare_data)
- {
- struct component_match *match = *matchptr;
- if (IS_ERR(match))
- return;
- if (!match || match->num == match->alloc) {
- size_t new_size = match ? match->alloc + 16 : 15;
- match = component_match_realloc(dev, match, new_size);
- *matchptr = match;
- if (IS_ERR(match))
- return;
- }
- match->compare[match->num].fn = compare;
- match->compare[match->num].data = compare_data;
- match->num++;
- }
- EXPORT_SYMBOL(component_match_add);
- int component_master_add_with_match(struct device *dev,
- const struct component_master_ops *ops,
- struct component_match *match)
- {
- struct master *master;
- int ret;
- if (ops->add_components && match)
- return -EINVAL;
- if (match) {
- /* Reallocate the match array for its true size */
- match = component_match_realloc(dev, match, match->num);
- if (IS_ERR(match))
- return PTR_ERR(match);
- }
- master = kzalloc(sizeof(*master), GFP_KERNEL);
- if (!master)
- return -ENOMEM;
- master->dev = dev;
- master->ops = ops;
- master->match = match;
- INIT_LIST_HEAD(&master->components);
- /* Add to the list of available masters. */
- mutex_lock(&component_mutex);
- list_add(&master->node, &masters);
- ret = try_to_bring_up_master(master, NULL);
- if (ret < 0) {
- /* Delete off the list if we weren't successful */
- list_del(&master->node);
- kfree(master);
- }
- mutex_unlock(&component_mutex);
- return ret < 0 ? ret : 0;
- }
- EXPORT_SYMBOL_GPL(component_master_add_with_match);
- int component_master_add(struct device *dev,
- const struct component_master_ops *ops)
- {
- return component_master_add_with_match(dev, ops, NULL);
- }
- EXPORT_SYMBOL_GPL(component_master_add);
- void component_master_del(struct device *dev,
- const struct component_master_ops *ops)
- {
- struct master *master;
- mutex_lock(&component_mutex);
- master = __master_find(dev, ops);
- if (master) {
- take_down_master(master);
- list_del(&master->node);
- kfree(master);
- }
- mutex_unlock(&component_mutex);
- }
- EXPORT_SYMBOL_GPL(component_master_del);
- static void component_unbind(struct component *component,
- struct master *master, void *data)
- {
- WARN_ON(!component->bound);
- component->ops->unbind(component->dev, master->dev, data);
- component->bound = false;
- /* Release all resources claimed in the binding of this component */
- devres_release_group(component->dev, component);
- }
- void component_unbind_all(struct device *master_dev, void *data)
- {
- struct master *master;
- struct component *c;
- WARN_ON(!mutex_is_locked(&component_mutex));
- master = __master_find(master_dev, NULL);
- if (!master)
- return;
- list_for_each_entry_reverse(c, &master->components, master_node)
- component_unbind(c, master, data);
- }
- EXPORT_SYMBOL_GPL(component_unbind_all);
- static int component_bind(struct component *component, struct master *master,
- void *data)
- {
- int ret;
- /*
- * Each component initialises inside its own devres group.
- * This allows us to roll-back a failed component without
- * affecting anything else.
- */
- if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
- return -ENOMEM;
- /*
- * Also open a group for the device itself: this allows us
- * to release the resources claimed against the sub-device
- * at the appropriate moment.
- */
- if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
- devres_release_group(master->dev, NULL);
- return -ENOMEM;
- }
- dev_dbg(master->dev, "binding %s (ops %ps)\n",
- dev_name(component->dev), component->ops);
- ret = component->ops->bind(component->dev, master->dev, data);
- if (!ret) {
- component->bound = true;
- /*
- * Close the component device's group so that resources
- * allocated in the binding are encapsulated for removal
- * at unbind. Remove the group on the DRM device as we
- * can clean those resources up independently.
- */
- devres_close_group(component->dev, NULL);
- devres_remove_group(master->dev, NULL);
- dev_info(master->dev, "bound %s (ops %ps)\n",
- dev_name(component->dev), component->ops);
- } else {
- devres_release_group(component->dev, NULL);
- devres_release_group(master->dev, NULL);
- dev_err(master->dev, "failed to bind %s (ops %ps): %d\n",
- dev_name(component->dev), component->ops, ret);
- }
- return ret;
- }
- int component_bind_all(struct device *master_dev, void *data)
- {
- struct master *master;
- struct component *c;
- int ret = 0;
- WARN_ON(!mutex_is_locked(&component_mutex));
- master = __master_find(master_dev, NULL);
- if (!master)
- return -EINVAL;
- list_for_each_entry(c, &master->components, master_node) {
- ret = component_bind(c, master, data);
- if (ret)
- break;
- }
- if (ret != 0) {
- list_for_each_entry_continue_reverse(c, &master->components,
- master_node)
- component_unbind(c, master, data);
- }
- return ret;
- }
- EXPORT_SYMBOL_GPL(component_bind_all);
- int component_add(struct device *dev, const struct component_ops *ops)
- {
- struct component *component;
- int ret;
- component = kzalloc(sizeof(*component), GFP_KERNEL);
- if (!component)
- return -ENOMEM;
- component->ops = ops;
- component->dev = dev;
- dev_dbg(dev, "adding component (ops %ps)\n", ops);
- mutex_lock(&component_mutex);
- list_add_tail(&component->node, &component_list);
- ret = try_to_bring_up_masters(component);
- if (ret < 0) {
- list_del(&component->node);
- kfree(component);
- }
- mutex_unlock(&component_mutex);
- return ret < 0 ? ret : 0;
- }
- EXPORT_SYMBOL_GPL(component_add);
- void component_del(struct device *dev, const struct component_ops *ops)
- {
- struct component *c, *component = NULL;
- mutex_lock(&component_mutex);
- list_for_each_entry(c, &component_list, node)
- if (c->dev == dev && c->ops == ops) {
- list_del(&c->node);
- component = c;
- break;
- }
- if (component && component->master)
- take_down_master(component->master);
- mutex_unlock(&component_mutex);
- WARN_ON(!component);
- kfree(component);
- }
- EXPORT_SYMBOL_GPL(component_del);
- MODULE_LICENSE("GPL v2");
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