533 lines
12 KiB
C
533 lines
12 KiB
C
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/*
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* Componentized device handling.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This is work in progress. We gather up the component devices into a list,
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* and bind them when instructed. At the moment, we're specific to the DRM
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* subsystem, and only handles one master device, but this doesn't have to be
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* the case.
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*/
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#include <linux/component.h>
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#include <linux/device.h>
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#include <linux/kref.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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struct component;
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struct component_match_array {
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void *data;
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int (*compare)(struct device *, void *);
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void (*release)(struct device *, void *);
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struct component *component;
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bool duplicate;
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};
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struct component_match {
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size_t alloc;
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size_t num;
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struct component_match_array *compare;
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};
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struct master {
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struct list_head node;
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bool bound;
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const struct component_master_ops *ops;
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struct device *dev;
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struct component_match *match;
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};
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struct component {
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struct list_head node;
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struct master *master;
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bool bound;
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const struct component_ops *ops;
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struct device *dev;
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};
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static DEFINE_MUTEX(component_mutex);
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static LIST_HEAD(component_list);
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static LIST_HEAD(masters);
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static struct master *__master_find(struct device *dev,
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const struct component_master_ops *ops)
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{
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struct master *m;
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list_for_each_entry(m, &masters, node)
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if (m->dev == dev && (!ops || m->ops == ops))
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return m;
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return NULL;
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}
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static struct component *find_component(struct master *master,
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int (*compare)(struct device *, void *), void *compare_data)
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{
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struct component *c;
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list_for_each_entry(c, &component_list, node) {
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if (c->master && c->master != master)
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continue;
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if (compare(c->dev, compare_data))
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return c;
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}
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return NULL;
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}
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static int find_components(struct master *master)
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{
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struct component_match *match = master->match;
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size_t i;
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int ret = 0;
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/*
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* Scan the array of match functions and attach
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* any components which are found to this master.
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*/
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for (i = 0; i < match->num; i++) {
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struct component_match_array *mc = &match->compare[i];
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struct component *c;
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dev_dbg(master->dev, "Looking for component %zu\n", i);
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if (match->compare[i].component)
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continue;
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c = find_component(master, mc->compare, mc->data);
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if (!c) {
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ret = -ENXIO;
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break;
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}
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dev_dbg(master->dev, "found component %s, duplicate %u\n", dev_name(c->dev), !!c->master);
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/* Attach this component to the master */
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match->compare[i].duplicate = !!c->master;
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match->compare[i].component = c;
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c->master = master;
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}
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return ret;
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}
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/* Detach component from associated master */
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static void remove_component(struct master *master, struct component *c)
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{
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size_t i;
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/* Detach the component from this master. */
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for (i = 0; i < master->match->num; i++)
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if (master->match->compare[i].component == c)
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master->match->compare[i].component = NULL;
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}
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/*
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* Try to bring up a master. If component is NULL, we're interested in
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* this master, otherwise it's a component which must be present to try
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* and bring up the master.
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*
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* Returns 1 for successful bringup, 0 if not ready, or -ve errno.
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*/
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static int try_to_bring_up_master(struct master *master,
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struct component *component)
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{
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int ret;
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dev_dbg(master->dev, "trying to bring up master\n");
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if (find_components(master)) {
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dev_dbg(master->dev, "master has incomplete components\n");
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return 0;
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}
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if (component && component->master != master) {
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dev_dbg(master->dev, "master is not for this component (%s)\n",
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dev_name(component->dev));
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return 0;
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}
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if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
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return -ENOMEM;
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/* Found all components */
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ret = master->ops->bind(master->dev);
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if (ret < 0) {
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devres_release_group(master->dev, NULL);
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if (ret != -EPROBE_DEFER)
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dev_info(master->dev, "master bind failed: %d\n", ret);
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return ret;
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}
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master->bound = true;
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return 1;
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}
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static int try_to_bring_up_masters(struct component *component)
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{
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struct master *m;
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int ret = 0;
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list_for_each_entry(m, &masters, node) {
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if (!m->bound) {
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ret = try_to_bring_up_master(m, component);
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if (ret != 0)
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break;
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}
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}
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return ret;
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}
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static void take_down_master(struct master *master)
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{
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if (master->bound) {
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master->ops->unbind(master->dev);
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devres_release_group(master->dev, NULL);
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master->bound = false;
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}
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}
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static void component_match_release(struct device *master,
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struct component_match *match)
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{
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unsigned int i;
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for (i = 0; i < match->num; i++) {
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struct component_match_array *mc = &match->compare[i];
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if (mc->release)
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mc->release(master, mc->data);
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}
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kfree(match->compare);
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}
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static void devm_component_match_release(struct device *dev, void *res)
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{
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component_match_release(dev, res);
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}
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static int component_match_realloc(struct device *dev,
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struct component_match *match, size_t num)
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{
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struct component_match_array *new;
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if (match->alloc == num)
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return 0;
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new = kmalloc_array(num, sizeof(*new), GFP_KERNEL);
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if (!new)
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return -ENOMEM;
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if (match->compare) {
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memcpy(new, match->compare, sizeof(*new) *
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min(match->num, num));
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kfree(match->compare);
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}
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match->compare = new;
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match->alloc = num;
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return 0;
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}
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/*
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* Add a component to be matched, with a release function.
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*
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* The match array is first created or extended if necessary.
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*/
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void component_match_add_release(struct device *master,
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struct component_match **matchptr,
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void (*release)(struct device *, void *),
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int (*compare)(struct device *, void *), void *compare_data)
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{
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struct component_match *match = *matchptr;
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if (IS_ERR(match))
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return;
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if (!match) {
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match = devres_alloc(devm_component_match_release,
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sizeof(*match), GFP_KERNEL);
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if (!match) {
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*matchptr = ERR_PTR(-ENOMEM);
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return;
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}
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devres_add(master, match);
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*matchptr = match;
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}
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if (match->num == match->alloc) {
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size_t new_size = match->alloc + 16;
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int ret;
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ret = component_match_realloc(master, match, new_size);
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if (ret) {
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*matchptr = ERR_PTR(ret);
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return;
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}
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}
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match->compare[match->num].compare = compare;
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match->compare[match->num].release = release;
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match->compare[match->num].data = compare_data;
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match->compare[match->num].component = NULL;
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match->num++;
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}
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EXPORT_SYMBOL(component_match_add_release);
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static void free_master(struct master *master)
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{
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struct component_match *match = master->match;
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int i;
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list_del(&master->node);
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if (match) {
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for (i = 0; i < match->num; i++) {
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struct component *c = match->compare[i].component;
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if (c)
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c->master = NULL;
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}
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}
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kfree(master);
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}
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int component_master_add_with_match(struct device *dev,
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const struct component_master_ops *ops,
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struct component_match *match)
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{
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struct master *master;
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int ret;
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/* Reallocate the match array for its true size */
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ret = component_match_realloc(dev, match, match->num);
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if (ret)
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return ret;
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master = kzalloc(sizeof(*master), GFP_KERNEL);
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if (!master)
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return -ENOMEM;
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master->dev = dev;
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master->ops = ops;
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master->match = match;
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/* Add to the list of available masters. */
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mutex_lock(&component_mutex);
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list_add(&master->node, &masters);
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ret = try_to_bring_up_master(master, NULL);
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if (ret < 0)
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free_master(master);
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mutex_unlock(&component_mutex);
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return ret < 0 ? ret : 0;
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}
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EXPORT_SYMBOL_GPL(component_master_add_with_match);
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void component_master_del(struct device *dev,
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const struct component_master_ops *ops)
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{
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struct master *master;
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mutex_lock(&component_mutex);
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master = __master_find(dev, ops);
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if (master) {
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take_down_master(master);
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free_master(master);
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}
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mutex_unlock(&component_mutex);
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}
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EXPORT_SYMBOL_GPL(component_master_del);
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static void component_unbind(struct component *component,
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struct master *master, void *data)
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{
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WARN_ON(!component->bound);
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component->ops->unbind(component->dev, master->dev, data);
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component->bound = false;
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/* Release all resources claimed in the binding of this component */
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devres_release_group(component->dev, component);
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}
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void component_unbind_all(struct device *master_dev, void *data)
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{
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struct master *master;
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struct component *c;
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size_t i;
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WARN_ON(!mutex_is_locked(&component_mutex));
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master = __master_find(master_dev, NULL);
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if (!master)
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return;
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/* Unbind components in reverse order */
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for (i = master->match->num; i--; )
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if (!master->match->compare[i].duplicate) {
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c = master->match->compare[i].component;
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component_unbind(c, master, data);
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}
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}
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EXPORT_SYMBOL_GPL(component_unbind_all);
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static int component_bind(struct component *component, struct master *master,
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void *data)
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{
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int ret;
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/*
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* Each component initialises inside its own devres group.
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* This allows us to roll-back a failed component without
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* affecting anything else.
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*/
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if (!devres_open_group(master->dev, NULL, GFP_KERNEL))
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return -ENOMEM;
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/*
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* Also open a group for the device itself: this allows us
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* to release the resources claimed against the sub-device
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* at the appropriate moment.
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*/
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if (!devres_open_group(component->dev, component, GFP_KERNEL)) {
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devres_release_group(master->dev, NULL);
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return -ENOMEM;
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}
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dev_dbg(master->dev, "binding %s (ops %ps)\n",
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|
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);
|
||
|
|
|
||
|
|
if (ret != -EPROBE_DEFER)
|
||
|
|
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;
|
||
|
|
size_t i;
|
||
|
|
int ret = 0;
|
||
|
|
|
||
|
|
WARN_ON(!mutex_is_locked(&component_mutex));
|
||
|
|
|
||
|
|
master = __master_find(master_dev, NULL);
|
||
|
|
if (!master)
|
||
|
|
return -EINVAL;
|
||
|
|
|
||
|
|
/* Bind components in match order */
|
||
|
|
for (i = 0; i < master->match->num; i++)
|
||
|
|
if (!master->match->compare[i].duplicate) {
|
||
|
|
c = master->match->compare[i].component;
|
||
|
|
ret = component_bind(c, master, data);
|
||
|
|
if (ret)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (ret != 0) {
|
||
|
|
for (; i > 0; i--)
|
||
|
|
if (!master->match->compare[i - 1].duplicate) {
|
||
|
|
c = master->match->compare[i - 1].component;
|
||
|
|
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) {
|
||
|
|
if (component->master)
|
||
|
|
remove_component(component->master, component);
|
||
|
|
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);
|
||
|
|
remove_component(component->master, component);
|
||
|
|
}
|
||
|
|
|
||
|
|
mutex_unlock(&component_mutex);
|
||
|
|
|
||
|
|
WARN_ON(!component);
|
||
|
|
kfree(component);
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL_GPL(component_del);
|
||
|
|
|
||
|
|
MODULE_LICENSE("GPL v2");
|