1 // SPDX-License-Identifier: GPL-2.0
3 * Interconnect framework core driver
5 * Copyright (c) 2017-2019, Linaro Ltd.
6 * Author: Georgi Djakov <georgi.djakov@linaro.org>
9 #include <linux/debugfs.h>
10 #include <linux/device.h>
11 #include <linux/idr.h>
12 #include <linux/init.h>
13 #include <linux/interconnect.h>
14 #include <linux/interconnect-provider.h>
15 #include <linux/list.h>
16 #include <linux/module.h>
17 #include <linux/mutex.h>
18 #include <linux/slab.h>
20 #include <linux/overflow.h>
24 #define CREATE_TRACE_POINTS
27 static DEFINE_IDR(icc_idr);
28 static LIST_HEAD(icc_providers);
29 static DEFINE_MUTEX(icc_lock);
30 static struct dentry *icc_debugfs_dir;
32 static void icc_summary_show_one(struct seq_file *s, struct icc_node *n)
37 seq_printf(s, "%-42s %12u %12u\n",
38 n->name, n->avg_bw, n->peak_bw);
41 static int icc_summary_show(struct seq_file *s, void *data)
43 struct icc_provider *provider;
45 seq_puts(s, " node tag avg peak\n");
46 seq_puts(s, "--------------------------------------------------------------------\n");
48 mutex_lock(&icc_lock);
50 list_for_each_entry(provider, &icc_providers, provider_list) {
53 list_for_each_entry(n, &provider->nodes, node_list) {
56 icc_summary_show_one(s, n);
57 hlist_for_each_entry(r, &n->req_list, req_node) {
61 seq_printf(s, " %-27s %12u %12u %12u\n",
62 dev_name(r->dev), r->tag, r->avg_bw,
68 mutex_unlock(&icc_lock);
72 DEFINE_SHOW_ATTRIBUTE(icc_summary);
74 static void icc_graph_show_link(struct seq_file *s, int level,
75 struct icc_node *n, struct icc_node *m)
77 seq_printf(s, "%s\"%d:%s\" -> \"%d:%s\"\n",
78 level == 2 ? "\t\t" : "\t",
79 n->id, n->name, m->id, m->name);
82 static void icc_graph_show_node(struct seq_file *s, struct icc_node *n)
84 seq_printf(s, "\t\t\"%d:%s\" [label=\"%d:%s",
85 n->id, n->name, n->id, n->name);
86 seq_printf(s, "\n\t\t\t|avg_bw=%ukBps", n->avg_bw);
87 seq_printf(s, "\n\t\t\t|peak_bw=%ukBps", n->peak_bw);
91 static int icc_graph_show(struct seq_file *s, void *data)
93 struct icc_provider *provider;
95 int cluster_index = 0;
98 seq_puts(s, "digraph {\n\trankdir = LR\n\tnode [shape = record]\n");
99 mutex_lock(&icc_lock);
101 /* draw providers as cluster subgraphs */
103 list_for_each_entry(provider, &icc_providers, provider_list) {
104 seq_printf(s, "\tsubgraph cluster_%d {\n", ++cluster_index);
106 seq_printf(s, "\t\tlabel = \"%s\"\n",
107 dev_name(provider->dev));
110 list_for_each_entry(n, &provider->nodes, node_list)
111 icc_graph_show_node(s, n);
113 /* draw internal links */
114 list_for_each_entry(n, &provider->nodes, node_list)
115 for (i = 0; i < n->num_links; ++i)
116 if (n->provider == n->links[i]->provider)
117 icc_graph_show_link(s, 2, n,
120 seq_puts(s, "\t}\n");
123 /* draw external links */
124 list_for_each_entry(provider, &icc_providers, provider_list)
125 list_for_each_entry(n, &provider->nodes, node_list)
126 for (i = 0; i < n->num_links; ++i)
127 if (n->provider != n->links[i]->provider)
128 icc_graph_show_link(s, 1, n,
131 mutex_unlock(&icc_lock);
136 DEFINE_SHOW_ATTRIBUTE(icc_graph);
138 static struct icc_node *node_find(const int id)
140 return idr_find(&icc_idr, id);
143 static struct icc_path *path_init(struct device *dev, struct icc_node *dst,
146 struct icc_node *node = dst;
147 struct icc_path *path;
150 path = kzalloc(struct_size(path, reqs, num_nodes), GFP_KERNEL);
152 return ERR_PTR(-ENOMEM);
154 path->num_nodes = num_nodes;
156 for (i = num_nodes - 1; i >= 0; i--) {
157 node->provider->users++;
158 hlist_add_head(&path->reqs[i].req_node, &node->req_list);
159 path->reqs[i].node = node;
160 path->reqs[i].dev = dev;
161 /* reference to previous node was saved during path traversal */
162 node = node->reverse;
168 static struct icc_path *path_find(struct device *dev, struct icc_node *src,
169 struct icc_node *dst)
171 struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
172 struct icc_node *n, *node = NULL;
173 struct list_head traverse_list;
174 struct list_head edge_list;
175 struct list_head visited_list;
179 INIT_LIST_HEAD(&traverse_list);
180 INIT_LIST_HEAD(&edge_list);
181 INIT_LIST_HEAD(&visited_list);
183 list_add(&src->search_list, &traverse_list);
187 list_for_each_entry_safe(node, n, &traverse_list, search_list) {
190 list_splice_init(&edge_list, &visited_list);
191 list_splice_init(&traverse_list, &visited_list);
194 for (i = 0; i < node->num_links; i++) {
195 struct icc_node *tmp = node->links[i];
198 path = ERR_PTR(-ENOENT);
202 if (tmp->is_traversed)
205 tmp->is_traversed = true;
207 list_add_tail(&tmp->search_list, &edge_list);
214 list_splice_init(&traverse_list, &visited_list);
215 list_splice_init(&edge_list, &traverse_list);
217 /* count the hops including the source */
220 } while (!list_empty(&traverse_list));
224 /* reset the traversed state */
225 list_for_each_entry_reverse(n, &visited_list, search_list)
226 n->is_traversed = false;
229 path = path_init(dev, dst, depth);
235 * We want the path to honor all bandwidth requests, so the average and peak
236 * bandwidth requirements from each consumer are aggregated at each node.
237 * The aggregation is platform specific, so each platform can customize it by
238 * implementing its own aggregate() function.
241 static int aggregate_requests(struct icc_node *node)
243 struct icc_provider *p = node->provider;
249 if (p->pre_aggregate)
250 p->pre_aggregate(node);
252 hlist_for_each_entry(r, &node->req_list, req_node)
253 p->aggregate(node, r->tag, r->avg_bw, r->peak_bw,
254 &node->avg_bw, &node->peak_bw);
259 static int apply_constraints(struct icc_path *path)
261 struct icc_node *next, *prev = NULL;
265 for (i = 0; i < path->num_nodes; i++) {
266 next = path->reqs[i].node;
269 * Both endpoints should be valid master-slave pairs of the
270 * same interconnect provider that will be configured.
272 if (!prev || next->provider != prev->provider) {
277 /* set the constraints */
278 ret = next->provider->set(prev, next);
288 int icc_std_aggregate(struct icc_node *node, u32 tag, u32 avg_bw,
289 u32 peak_bw, u32 *agg_avg, u32 *agg_peak)
292 *agg_peak = max(*agg_peak, peak_bw);
296 EXPORT_SYMBOL_GPL(icc_std_aggregate);
298 /* of_icc_xlate_onecell() - Translate function using a single index.
299 * @spec: OF phandle args to map into an interconnect node.
300 * @data: private data (pointer to struct icc_onecell_data)
302 * This is a generic translate function that can be used to model simple
303 * interconnect providers that have one device tree node and provide
304 * multiple interconnect nodes. A single cell is used as an index into
305 * an array of icc nodes specified in the icc_onecell_data struct when
306 * registering the provider.
308 struct icc_node *of_icc_xlate_onecell(struct of_phandle_args *spec,
311 struct icc_onecell_data *icc_data = data;
312 unsigned int idx = spec->args[0];
314 if (idx >= icc_data->num_nodes) {
315 pr_err("%s: invalid index %u\n", __func__, idx);
316 return ERR_PTR(-EINVAL);
319 return icc_data->nodes[idx];
321 EXPORT_SYMBOL_GPL(of_icc_xlate_onecell);
324 * of_icc_get_from_provider() - Look-up interconnect node
325 * @spec: OF phandle args to use for look-up
327 * Looks for interconnect provider under the node specified by @spec and if
328 * found, uses xlate function of the provider to map phandle args to node.
330 * Returns a valid pointer to struct icc_node on success or ERR_PTR()
333 static struct icc_node *of_icc_get_from_provider(struct of_phandle_args *spec)
335 struct icc_node *node = ERR_PTR(-EPROBE_DEFER);
336 struct icc_provider *provider;
338 if (!spec || spec->args_count != 1)
339 return ERR_PTR(-EINVAL);
341 mutex_lock(&icc_lock);
342 list_for_each_entry(provider, &icc_providers, provider_list) {
343 if (provider->dev->of_node == spec->np)
344 node = provider->xlate(spec, provider->data);
348 mutex_unlock(&icc_lock);
354 * of_icc_get_by_index() - get a path handle from a DT node based on index
355 * @dev: device pointer for the consumer device
356 * @idx: interconnect path index
358 * This function will search for a path between two endpoints and return an
359 * icc_path handle on success. Use icc_put() to release constraints when they
360 * are not needed anymore.
361 * If the interconnect API is disabled, NULL is returned and the consumer
362 * drivers will still build. Drivers are free to handle this specifically,
363 * but they don't have to.
365 * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned
366 * when the API is disabled or the "interconnects" DT property is missing.
368 struct icc_path *of_icc_get_by_index(struct device *dev, int idx)
370 struct icc_path *path;
371 struct icc_node *src_node, *dst_node;
372 struct device_node *np;
373 struct of_phandle_args src_args, dst_args;
376 if (!dev || !dev->of_node)
377 return ERR_PTR(-ENODEV);
382 * When the consumer DT node do not have "interconnects" property
383 * return a NULL path to skip setting constraints.
385 if (!of_find_property(np, "interconnects", NULL))
389 * We use a combination of phandle and specifier for endpoint. For now
390 * lets support only global ids and extend this in the future if needed
391 * without breaking DT compatibility.
393 ret = of_parse_phandle_with_args(np, "interconnects",
394 "#interconnect-cells", idx * 2,
399 of_node_put(src_args.np);
401 ret = of_parse_phandle_with_args(np, "interconnects",
402 "#interconnect-cells", idx * 2 + 1,
407 of_node_put(dst_args.np);
409 src_node = of_icc_get_from_provider(&src_args);
411 if (IS_ERR(src_node)) {
412 if (PTR_ERR(src_node) != -EPROBE_DEFER)
413 dev_err(dev, "error finding src node: %ld\n",
415 return ERR_CAST(src_node);
418 dst_node = of_icc_get_from_provider(&dst_args);
420 if (IS_ERR(dst_node)) {
421 if (PTR_ERR(dst_node) != -EPROBE_DEFER)
422 dev_err(dev, "error finding dst node: %ld\n",
424 return ERR_CAST(dst_node);
427 mutex_lock(&icc_lock);
428 path = path_find(dev, src_node, dst_node);
429 mutex_unlock(&icc_lock);
431 dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
435 path->name = kasprintf(GFP_KERNEL, "%s-%s",
436 src_node->name, dst_node->name);
439 return ERR_PTR(-ENOMEM);
444 EXPORT_SYMBOL_GPL(of_icc_get_by_index);
447 * of_icc_get() - get a path handle from a DT node based on name
448 * @dev: device pointer for the consumer device
449 * @name: interconnect path name
451 * This function will search for a path between two endpoints and return an
452 * icc_path handle on success. Use icc_put() to release constraints when they
453 * are not needed anymore.
454 * If the interconnect API is disabled, NULL is returned and the consumer
455 * drivers will still build. Drivers are free to handle this specifically,
456 * but they don't have to.
458 * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned
459 * when the API is disabled or the "interconnects" DT property is missing.
461 struct icc_path *of_icc_get(struct device *dev, const char *name)
463 struct device_node *np;
466 if (!dev || !dev->of_node)
467 return ERR_PTR(-ENODEV);
472 * When the consumer DT node do not have "interconnects" property
473 * return a NULL path to skip setting constraints.
475 if (!of_find_property(np, "interconnects", NULL))
479 * We use a combination of phandle and specifier for endpoint. For now
480 * lets support only global ids and extend this in the future if needed
481 * without breaking DT compatibility.
484 idx = of_property_match_string(np, "interconnect-names", name);
489 return of_icc_get_by_index(dev, idx);
491 EXPORT_SYMBOL_GPL(of_icc_get);
494 * icc_set_tag() - set an optional tag on a path
495 * @path: the path we want to tag
496 * @tag: the tag value
498 * This function allows consumers to append a tag to the requests associated
499 * with a path, so that a different aggregation could be done based on this tag.
501 void icc_set_tag(struct icc_path *path, u32 tag)
508 mutex_lock(&icc_lock);
510 for (i = 0; i < path->num_nodes; i++)
511 path->reqs[i].tag = tag;
513 mutex_unlock(&icc_lock);
515 EXPORT_SYMBOL_GPL(icc_set_tag);
518 * icc_get_name() - Get name of the icc path
519 * @path: reference to the path returned by icc_get()
521 * This function is used by an interconnect consumer to get the name of the icc
524 * Returns a valid pointer on success, or NULL otherwise.
526 const char *icc_get_name(struct icc_path *path)
533 EXPORT_SYMBOL_GPL(icc_get_name);
536 * icc_set_bw() - set bandwidth constraints on an interconnect path
537 * @path: reference to the path returned by icc_get()
538 * @avg_bw: average bandwidth in kilobytes per second
539 * @peak_bw: peak bandwidth in kilobytes per second
541 * This function is used by an interconnect consumer to express its own needs
542 * in terms of bandwidth for a previously requested path between two endpoints.
543 * The requests are aggregated and each node is updated accordingly. The entire
544 * path is locked by a mutex to ensure that the set() is completed.
545 * The @path can be NULL when the "interconnects" DT properties is missing,
546 * which will mean that no constraints will be set.
548 * Returns 0 on success, or an appropriate error code otherwise.
550 int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw)
552 struct icc_node *node;
553 u32 old_avg, old_peak;
560 if (WARN_ON(IS_ERR(path) || !path->num_nodes))
563 mutex_lock(&icc_lock);
565 old_avg = path->reqs[0].avg_bw;
566 old_peak = path->reqs[0].peak_bw;
568 for (i = 0; i < path->num_nodes; i++) {
569 node = path->reqs[i].node;
571 /* update the consumer request for this path */
572 path->reqs[i].avg_bw = avg_bw;
573 path->reqs[i].peak_bw = peak_bw;
575 /* aggregate requests for this node */
576 aggregate_requests(node);
578 trace_icc_set_bw(path, node, i, avg_bw, peak_bw);
581 ret = apply_constraints(path);
583 pr_debug("interconnect: error applying constraints (%d)\n",
586 for (i = 0; i < path->num_nodes; i++) {
587 node = path->reqs[i].node;
588 path->reqs[i].avg_bw = old_avg;
589 path->reqs[i].peak_bw = old_peak;
590 aggregate_requests(node);
592 apply_constraints(path);
595 mutex_unlock(&icc_lock);
597 trace_icc_set_bw_end(path, ret);
601 EXPORT_SYMBOL_GPL(icc_set_bw);
604 * icc_get() - return a handle for path between two endpoints
605 * @dev: the device requesting the path
606 * @src_id: source device port id
607 * @dst_id: destination device port id
609 * This function will search for a path between two endpoints and return an
610 * icc_path handle on success. Use icc_put() to release
611 * constraints when they are not needed anymore.
612 * If the interconnect API is disabled, NULL is returned and the consumer
613 * drivers will still build. Drivers are free to handle this specifically,
614 * but they don't have to.
616 * Return: icc_path pointer on success, ERR_PTR() on error or NULL if the
617 * interconnect API is disabled.
619 struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id)
621 struct icc_node *src, *dst;
622 struct icc_path *path = ERR_PTR(-EPROBE_DEFER);
624 mutex_lock(&icc_lock);
626 src = node_find(src_id);
630 dst = node_find(dst_id);
634 path = path_find(dev, src, dst);
636 dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
640 path->name = kasprintf(GFP_KERNEL, "%s-%s", src->name, dst->name);
643 path = ERR_PTR(-ENOMEM);
646 mutex_unlock(&icc_lock);
649 EXPORT_SYMBOL_GPL(icc_get);
652 * icc_put() - release the reference to the icc_path
653 * @path: interconnect path
655 * Use this function to release the constraints on a path when the path is
656 * no longer needed. The constraints will be re-aggregated.
658 void icc_put(struct icc_path *path)
660 struct icc_node *node;
664 if (!path || WARN_ON(IS_ERR(path)))
667 ret = icc_set_bw(path, 0, 0);
669 pr_err("%s: error (%d)\n", __func__, ret);
671 mutex_lock(&icc_lock);
672 for (i = 0; i < path->num_nodes; i++) {
673 node = path->reqs[i].node;
674 hlist_del(&path->reqs[i].req_node);
675 if (!WARN_ON(!node->provider->users))
676 node->provider->users--;
678 mutex_unlock(&icc_lock);
680 kfree_const(path->name);
683 EXPORT_SYMBOL_GPL(icc_put);
685 static struct icc_node *icc_node_create_nolock(int id)
687 struct icc_node *node;
689 /* check if node already exists */
690 node = node_find(id);
694 node = kzalloc(sizeof(*node), GFP_KERNEL);
696 return ERR_PTR(-ENOMEM);
698 id = idr_alloc(&icc_idr, node, id, id + 1, GFP_KERNEL);
700 WARN(1, "%s: couldn't get idr\n", __func__);
711 * icc_node_create() - create a node
714 * Return: icc_node pointer on success, or ERR_PTR() on error
716 struct icc_node *icc_node_create(int id)
718 struct icc_node *node;
720 mutex_lock(&icc_lock);
722 node = icc_node_create_nolock(id);
724 mutex_unlock(&icc_lock);
728 EXPORT_SYMBOL_GPL(icc_node_create);
731 * icc_node_destroy() - destroy a node
734 void icc_node_destroy(int id)
736 struct icc_node *node;
738 mutex_lock(&icc_lock);
740 node = node_find(id);
742 idr_remove(&icc_idr, node->id);
743 WARN_ON(!hlist_empty(&node->req_list));
746 mutex_unlock(&icc_lock);
750 EXPORT_SYMBOL_GPL(icc_node_destroy);
753 * icc_link_create() - create a link between two nodes
754 * @node: source node id
755 * @dst_id: destination node id
757 * Create a link between two nodes. The nodes might belong to different
758 * interconnect providers and the @dst_id node might not exist (if the
759 * provider driver has not probed yet). So just create the @dst_id node
760 * and when the actual provider driver is probed, the rest of the node
763 * Return: 0 on success, or an error code otherwise
765 int icc_link_create(struct icc_node *node, const int dst_id)
767 struct icc_node *dst;
768 struct icc_node **new;
774 mutex_lock(&icc_lock);
776 dst = node_find(dst_id);
778 dst = icc_node_create_nolock(dst_id);
786 new = krealloc(node->links,
787 (node->num_links + 1) * sizeof(*node->links),
795 node->links[node->num_links++] = dst;
798 mutex_unlock(&icc_lock);
802 EXPORT_SYMBOL_GPL(icc_link_create);
805 * icc_link_destroy() - destroy a link between two nodes
806 * @src: pointer to source node
807 * @dst: pointer to destination node
809 * Return: 0 on success, or an error code otherwise
811 int icc_link_destroy(struct icc_node *src, struct icc_node *dst)
813 struct icc_node **new;
817 if (IS_ERR_OR_NULL(src))
820 if (IS_ERR_OR_NULL(dst))
823 mutex_lock(&icc_lock);
825 for (slot = 0; slot < src->num_links; slot++)
826 if (src->links[slot] == dst)
829 if (WARN_ON(slot == src->num_links)) {
834 src->links[slot] = src->links[--src->num_links];
836 new = krealloc(src->links, src->num_links * sizeof(*src->links),
842 mutex_unlock(&icc_lock);
846 EXPORT_SYMBOL_GPL(icc_link_destroy);
849 * icc_node_add() - add interconnect node to interconnect provider
850 * @node: pointer to the interconnect node
851 * @provider: pointer to the interconnect provider
853 void icc_node_add(struct icc_node *node, struct icc_provider *provider)
855 mutex_lock(&icc_lock);
857 node->provider = provider;
858 list_add_tail(&node->node_list, &provider->nodes);
860 mutex_unlock(&icc_lock);
862 EXPORT_SYMBOL_GPL(icc_node_add);
865 * icc_node_del() - delete interconnect node from interconnect provider
866 * @node: pointer to the interconnect node
868 void icc_node_del(struct icc_node *node)
870 mutex_lock(&icc_lock);
872 list_del(&node->node_list);
874 mutex_unlock(&icc_lock);
876 EXPORT_SYMBOL_GPL(icc_node_del);
879 * icc_nodes_remove() - remove all previously added nodes from provider
880 * @provider: the interconnect provider we are removing nodes from
882 * Return: 0 on success, or an error code otherwise
884 int icc_nodes_remove(struct icc_provider *provider)
886 struct icc_node *n, *tmp;
888 if (WARN_ON(IS_ERR_OR_NULL(provider)))
891 list_for_each_entry_safe_reverse(n, tmp, &provider->nodes, node_list) {
893 icc_node_destroy(n->id);
898 EXPORT_SYMBOL_GPL(icc_nodes_remove);
901 * icc_provider_add() - add a new interconnect provider
902 * @provider: the interconnect provider that will be added into topology
904 * Return: 0 on success, or an error code otherwise
906 int icc_provider_add(struct icc_provider *provider)
908 if (WARN_ON(!provider->set))
910 if (WARN_ON(!provider->xlate))
913 mutex_lock(&icc_lock);
915 INIT_LIST_HEAD(&provider->nodes);
916 list_add_tail(&provider->provider_list, &icc_providers);
918 mutex_unlock(&icc_lock);
920 dev_dbg(provider->dev, "interconnect provider added to topology\n");
924 EXPORT_SYMBOL_GPL(icc_provider_add);
927 * icc_provider_del() - delete previously added interconnect provider
928 * @provider: the interconnect provider that will be removed from topology
930 * Return: 0 on success, or an error code otherwise
932 int icc_provider_del(struct icc_provider *provider)
934 mutex_lock(&icc_lock);
935 if (provider->users) {
936 pr_warn("interconnect provider still has %d users\n",
938 mutex_unlock(&icc_lock);
942 if (!list_empty(&provider->nodes)) {
943 pr_warn("interconnect provider still has nodes\n");
944 mutex_unlock(&icc_lock);
948 list_del(&provider->provider_list);
949 mutex_unlock(&icc_lock);
953 EXPORT_SYMBOL_GPL(icc_provider_del);
955 static int __init icc_init(void)
957 icc_debugfs_dir = debugfs_create_dir("interconnect", NULL);
958 debugfs_create_file("interconnect_summary", 0444,
959 icc_debugfs_dir, NULL, &icc_summary_fops);
960 debugfs_create_file("interconnect_graph", 0444,
961 icc_debugfs_dir, NULL, &icc_graph_fops);
965 device_initcall(icc_init);
967 MODULE_AUTHOR("Georgi Djakov <georgi.djakov@linaro.org>");
968 MODULE_DESCRIPTION("Interconnect Driver Core");
969 MODULE_LICENSE("GPL v2");