diff options
Diffstat (limited to 'drivers/interconnect/core.c')
| -rw-r--r-- | drivers/interconnect/core.c | 799 |
1 files changed, 799 insertions, 0 deletions
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c new file mode 100644 index 000000000000..6005a1c189f6 --- /dev/null +++ b/drivers/interconnect/core.c @@ -0,0 +1,799 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Interconnect framework core driver + * + * Copyright (c) 2017-2019, Linaro Ltd. + * Author: Georgi Djakov <georgi.djakov@linaro.org> + */ + +#include <linux/debugfs.h> +#include <linux/device.h> +#include <linux/idr.h> +#include <linux/init.h> +#include <linux/interconnect.h> +#include <linux/interconnect-provider.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/slab.h> +#include <linux/of.h> +#include <linux/overflow.h> + +static DEFINE_IDR(icc_idr); +static LIST_HEAD(icc_providers); +static DEFINE_MUTEX(icc_lock); +static struct dentry *icc_debugfs_dir; + +/** + * struct icc_req - constraints that are attached to each node + * @req_node: entry in list of requests for the particular @node + * @node: the interconnect node to which this constraint applies + * @dev: reference to the device that sets the constraints + * @avg_bw: an integer describing the average bandwidth in kBps + * @peak_bw: an integer describing the peak bandwidth in kBps + */ +struct icc_req { + struct hlist_node req_node; + struct icc_node *node; + struct device *dev; + u32 avg_bw; + u32 peak_bw; +}; + +/** + * struct icc_path - interconnect path structure + * @num_nodes: number of hops (nodes) + * @reqs: array of the requests applicable to this path of nodes + */ +struct icc_path { + size_t num_nodes; + struct icc_req reqs[]; +}; + +static void icc_summary_show_one(struct seq_file *s, struct icc_node *n) +{ + if (!n) + return; + + seq_printf(s, "%-30s %12u %12u\n", + n->name, n->avg_bw, n->peak_bw); +} + +static int icc_summary_show(struct seq_file *s, void *data) +{ + struct icc_provider *provider; + + seq_puts(s, " node avg peak\n"); + seq_puts(s, "--------------------------------------------------------\n"); + + mutex_lock(&icc_lock); + + list_for_each_entry(provider, &icc_providers, provider_list) { + struct icc_node *n; + + list_for_each_entry(n, &provider->nodes, node_list) { + struct icc_req *r; + + icc_summary_show_one(s, n); + hlist_for_each_entry(r, &n->req_list, req_node) { + if (!r->dev) + continue; + + seq_printf(s, " %-26s %12u %12u\n", + dev_name(r->dev), r->avg_bw, + r->peak_bw); + } + } + } + + mutex_unlock(&icc_lock); + + return 0; +} + +static int icc_summary_open(struct inode *inode, struct file *file) +{ + return single_open(file, icc_summary_show, inode->i_private); +} + +static const struct file_operations icc_summary_fops = { + .open = icc_summary_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static struct icc_node *node_find(const int id) +{ + return idr_find(&icc_idr, id); +} + +static struct icc_path *path_init(struct device *dev, struct icc_node *dst, + ssize_t num_nodes) +{ + struct icc_node *node = dst; + struct icc_path *path; + int i; + + path = kzalloc(struct_size(path, reqs, num_nodes), GFP_KERNEL); + if (!path) + return ERR_PTR(-ENOMEM); + + path->num_nodes = num_nodes; + + for (i = num_nodes - 1; i >= 0; i--) { + node->provider->users++; + hlist_add_head(&path->reqs[i].req_node, &node->req_list); + path->reqs[i].node = node; + path->reqs[i].dev = dev; + /* reference to previous node was saved during path traversal */ + node = node->reverse; + } + + return path; +} + +static struct icc_path *path_find(struct device *dev, struct icc_node *src, + struct icc_node *dst) +{ + struct icc_path *path = ERR_PTR(-EPROBE_DEFER); + struct icc_node *n, *node = NULL; + struct list_head traverse_list; + struct list_head edge_list; + struct list_head visited_list; + size_t i, depth = 1; + bool found = false; + + INIT_LIST_HEAD(&traverse_list); + INIT_LIST_HEAD(&edge_list); + INIT_LIST_HEAD(&visited_list); + + list_add(&src->search_list, &traverse_list); + src->reverse = NULL; + + do { + list_for_each_entry_safe(node, n, &traverse_list, search_list) { + if (node == dst) { + found = true; + list_splice_init(&edge_list, &visited_list); + list_splice_init(&traverse_list, &visited_list); + break; + } + for (i = 0; i < node->num_links; i++) { + struct icc_node *tmp = node->links[i]; + + if (!tmp) { + path = ERR_PTR(-ENOENT); + goto out; + } + + if (tmp->is_traversed) + continue; + + tmp->is_traversed = true; + tmp->reverse = node; + list_add_tail(&tmp->search_list, &edge_list); + } + } + + if (found) + break; + + list_splice_init(&traverse_list, &visited_list); + list_splice_init(&edge_list, &traverse_list); + + /* count the hops including the source */ + depth++; + + } while (!list_empty(&traverse_list)); + +out: + + /* reset the traversed state */ + list_for_each_entry_reverse(n, &visited_list, search_list) + n->is_traversed = false; + + if (found) + path = path_init(dev, dst, depth); + + return path; +} + +/* + * We want the path to honor all bandwidth requests, so the average and peak + * bandwidth requirements from each consumer are aggregated at each node. + * The aggregation is platform specific, so each platform can customize it by + * implementing its own aggregate() function. + */ + +static int aggregate_requests(struct icc_node *node) +{ + struct icc_provider *p = node->provider; + struct icc_req *r; + + node->avg_bw = 0; + node->peak_bw = 0; + + hlist_for_each_entry(r, &node->req_list, req_node) + p->aggregate(node, r->avg_bw, r->peak_bw, + &node->avg_bw, &node->peak_bw); + + return 0; +} + +static int apply_constraints(struct icc_path *path) +{ + struct icc_node *next, *prev = NULL; + int ret = -EINVAL; + int i; + + for (i = 0; i < path->num_nodes; i++) { + next = path->reqs[i].node; + + /* + * Both endpoints should be valid master-slave pairs of the + * same interconnect provider that will be configured. + */ + if (!prev || next->provider != prev->provider) { + prev = next; + continue; + } + + /* set the constraints */ + ret = next->provider->set(prev, next); + if (ret) + goto out; + + prev = next; + } +out: + return ret; +} + +/* of_icc_xlate_onecell() - Translate function using a single index. + * @spec: OF phandle args to map into an interconnect node. + * @data: private data (pointer to struct icc_onecell_data) + * + * This is a generic translate function that can be used to model simple + * interconnect providers that have one device tree node and provide + * multiple interconnect nodes. A single cell is used as an index into + * an array of icc nodes specified in the icc_onecell_data struct when + * registering the provider. + */ +struct icc_node *of_icc_xlate_onecell(struct of_phandle_args *spec, + void *data) +{ + struct icc_onecell_data *icc_data = data; + unsigned int idx = spec->args[0]; + + if (idx >= icc_data->num_nodes) { + pr_err("%s: invalid index %u\n", __func__, idx); + return ERR_PTR(-EINVAL); + } + + return icc_data->nodes[idx]; +} +EXPORT_SYMBOL_GPL(of_icc_xlate_onecell); + +/** + * of_icc_get_from_provider() - Look-up interconnect node + * @spec: OF phandle args to use for look-up + * + * Looks for interconnect provider under the node specified by @spec and if + * found, uses xlate function of the provider to map phandle args to node. + * + * Returns a valid pointer to struct icc_node on success or ERR_PTR() + * on failure. + */ +static struct icc_node *of_icc_get_from_provider(struct of_phandle_args *spec) +{ + struct icc_node *node = ERR_PTR(-EPROBE_DEFER); + struct icc_provider *provider; + + if (!spec || spec->args_count != 1) + return ERR_PTR(-EINVAL); + + mutex_lock(&icc_lock); + list_for_each_entry(provider, &icc_providers, provider_list) { + if (provider->dev->of_node == spec->np) + node = provider->xlate(spec, provider->data); + if (!IS_ERR(node)) + break; + } + mutex_unlock(&icc_lock); + + return node; +} + +/** + * of_icc_get() - get a path handle from a DT node based on name + * @dev: device pointer for the consumer device + * @name: interconnect path name + * + * This function will search for a path between two endpoints and return an + * icc_path handle on success. Use icc_put() to release constraints when they + * are not needed anymore. + * If the interconnect API is disabled, NULL is returned and the consumer + * drivers will still build. Drivers are free to handle this specifically, + * but they don't have to. + * + * Return: icc_path pointer on success or ERR_PTR() on error. NULL is returned + * when the API is disabled or the "interconnects" DT property is missing. + */ +struct icc_path *of_icc_get(struct device *dev, const char *name) +{ + struct icc_path *path = ERR_PTR(-EPROBE_DEFER); + struct icc_node *src_node, *dst_node; + struct device_node *np = NULL; + struct of_phandle_args src_args, dst_args; + int idx = 0; + int ret; + + if (!dev || !dev->of_node) + return ERR_PTR(-ENODEV); + + np = dev->of_node; + + /* + * When the consumer DT node do not have "interconnects" property + * return a NULL path to skip setting constraints. + */ + if (!of_find_property(np, "interconnects", NULL)) + return NULL; + + /* + * We use a combination of phandle and specifier for endpoint. For now + * lets support only global ids and extend this in the future if needed + * without breaking DT compatibility. + */ + if (name) { + idx = of_property_match_string(np, "interconnect-names", name); + if (idx < 0) + return ERR_PTR(idx); + } + + ret = of_parse_phandle_with_args(np, "interconnects", + "#interconnect-cells", idx * 2, + &src_args); + if (ret) + return ERR_PTR(ret); + + of_node_put(src_args.np); + + ret = of_parse_phandle_with_args(np, "interconnects", + "#interconnect-cells", idx * 2 + 1, + &dst_args); + if (ret) + return ERR_PTR(ret); + + of_node_put(dst_args.np); + + src_node = of_icc_get_from_provider(&src_args); + + if (IS_ERR(src_node)) { + if (PTR_ERR(src_node) != -EPROBE_DEFER) + dev_err(dev, "error finding src node: %ld\n", + PTR_ERR(src_node)); + return ERR_CAST(src_node); + } + + dst_node = of_icc_get_from_provider(&dst_args); + + if (IS_ERR(dst_node)) { + if (PTR_ERR(dst_node) != -EPROBE_DEFER) + dev_err(dev, "error finding dst node: %ld\n", + PTR_ERR(dst_node)); + return ERR_CAST(dst_node); + } + + mutex_lock(&icc_lock); + path = path_find(dev, src_node, dst_node); + if (IS_ERR(path)) + dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path)); + mutex_unlock(&icc_lock); + + return path; +} +EXPORT_SYMBOL_GPL(of_icc_get); + +/** + * icc_set_bw() - set bandwidth constraints on an interconnect path + * @path: reference to the path returned by icc_get() + * @avg_bw: average bandwidth in kilobytes per second + * @peak_bw: peak bandwidth in kilobytes per second + * + * This function is used by an interconnect consumer to express its own needs + * in terms of bandwidth for a previously requested path between two endpoints. + * The requests are aggregated and each node is updated accordingly. The entire + * path is locked by a mutex to ensure that the set() is completed. + * The @path can be NULL when the "interconnects" DT properties is missing, + * which will mean that no constraints will be set. + * + * Returns 0 on success, or an appropriate error code otherwise. + */ +int icc_set_bw(struct icc_path *path, u32 avg_bw, u32 peak_bw) +{ + struct icc_node *node; + u32 old_avg, old_peak; + size_t i; + int ret; + + if (!path || !path->num_nodes) + return 0; + + mutex_lock(&icc_lock); + + old_avg = path->reqs[0].avg_bw; + old_peak = path->reqs[0].peak_bw; + + for (i = 0; i < path->num_nodes; i++) { + node = path->reqs[i].node; + + /* update the consumer request for this path */ + path->reqs[i].avg_bw = avg_bw; + path->reqs[i].peak_bw = peak_bw; + + /* aggregate requests for this node */ + aggregate_requests(node); + } + + ret = apply_constraints(path); + if (ret) { + pr_debug("interconnect: error applying constraints (%d)\n", + ret); + + for (i = 0; i < path->num_nodes; i++) { + node = path->reqs[i].node; + path->reqs[i].avg_bw = old_avg; + path->reqs[i].peak_bw = old_peak; + aggregate_requests(node); + } + apply_constraints(path); + } + + mutex_unlock(&icc_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(icc_set_bw); + +/** + * icc_get() - return a handle for path between two endpoints + * @dev: the device requesting the path + * @src_id: source device port id + * @dst_id: destination device port id + * + * This function will search for a path between two endpoints and return an + * icc_path handle on success. Use icc_put() to release + * constraints when they are not needed anymore. + * If the interconnect API is disabled, NULL is returned and the consumer + * drivers will still build. Drivers are free to handle this specifically, + * but they don't have to. + * + * Return: icc_path pointer on success, ERR_PTR() on error or NULL if the + * interconnect API is disabled. + */ +struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id) +{ + struct icc_node *src, *dst; + struct icc_path *path = ERR_PTR(-EPROBE_DEFER); + + mutex_lock(&icc_lock); + + src = node_find(src_id); + if (!src) + goto out; + + dst = node_find(dst_id); + if (!dst) + goto out; + + path = path_find(dev, src, dst); + if (IS_ERR(path)) + dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path)); + +out: + mutex_unlock(&icc_lock); + return path; +} +EXPORT_SYMBOL_GPL(icc_get); + +/** + * icc_put() - release the reference to the icc_path + * @path: interconnect path + * + * Use this function to release the constraints on a path when the path is + * no longer needed. The constraints will be re-aggregated. + */ +void icc_put(struct icc_path *path) +{ + struct icc_node *node; + size_t i; + int ret; + + if (!path || WARN_ON(IS_ERR(path))) + return; + + ret = icc_set_bw(path, 0, 0); + if (ret) + pr_err("%s: error (%d)\n", __func__, ret); + + mutex_lock(&icc_lock); + for (i = 0; i < path->num_nodes; i++) { + node = path->reqs[i].node; + hlist_del(&path->reqs[i].req_node); + if (!WARN_ON(!node->provider->users)) + node->provider->users--; + } + mutex_unlock(&icc_lock); + + kfree(path); +} +EXPORT_SYMBOL_GPL(icc_put); + +static struct icc_node *icc_node_create_nolock(int id) +{ + struct icc_node *node; + + /* check if node already exists */ + node = node_find(id); + if (node) + return node; + + node = kzalloc(sizeof(*node), GFP_KERNEL); + if (!node) + return ERR_PTR(-ENOMEM); + + id = idr_alloc(&icc_idr, node, id, id + 1, GFP_KERNEL); + if (id < 0) { + WARN(1, "%s: couldn't get idr\n", __func__); + kfree(node); + return ERR_PTR(id); + } + + node->id = id; + + return node; +} + +/** + * icc_node_create() - create a node + * @id: node id + * + * Return: icc_node pointer on success, or ERR_PTR() on error + */ +struct icc_node *icc_node_create(int id) +{ + struct icc_node *node; + + mutex_lock(&icc_lock); + + node = icc_node_create_nolock(id); + + mutex_unlock(&icc_lock); + + return node; +} +EXPORT_SYMBOL_GPL(icc_node_create); + +/** + * icc_node_destroy() - destroy a node + * @id: node id + */ +void icc_node_destroy(int id) +{ + struct icc_node *node; + + mutex_lock(&icc_lock); + + node = node_find(id); + if (node) { + idr_remove(&icc_idr, node->id); + WARN_ON(!hlist_empty(&node->req_list)); + } + + mutex_unlock(&icc_lock); + + kfree(node); +} +EXPORT_SYMBOL_GPL(icc_node_destroy); + +/** + * icc_link_create() - create a link between two nodes + * @node: source node id + * @dst_id: destination node id + * + * Create a link between two nodes. The nodes might belong to different + * interconnect providers and the @dst_id node might not exist (if the + * provider driver has not probed yet). So just create the @dst_id node + * and when the actual provider driver is probed, the rest of the node + * data is filled. + * + * Return: 0 on success, or an error code otherwise + */ +int icc_link_create(struct icc_node *node, const int dst_id) +{ + struct icc_node *dst; + struct icc_node **new; + int ret = 0; + + if (!node->provider) + return -EINVAL; + + mutex_lock(&icc_lock); + + dst = node_find(dst_id); + if (!dst) { + dst = icc_node_create_nolock(dst_id); + + if (IS_ERR(dst)) { + ret = PTR_ERR(dst); + goto out; + } + } + + new = krealloc(node->links, + (node->num_links + 1) * sizeof(*node->links), + GFP_KERNEL); + if (!new) { + ret = -ENOMEM; + goto out; + } + + node->links = new; + node->links[node->num_links++] = dst; + +out: + mutex_unlock(&icc_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(icc_link_create); + +/** + * icc_link_destroy() - destroy a link between two nodes + * @src: pointer to source node + * @dst: pointer to destination node + * + * Return: 0 on success, or an error code otherwise + */ +int icc_link_destroy(struct icc_node *src, struct icc_node *dst) +{ + struct icc_node **new; + size_t slot; + int ret = 0; + + if (IS_ERR_OR_NULL(src)) + return -EINVAL; + + if (IS_ERR_OR_NULL(dst)) + return -EINVAL; + + mutex_lock(&icc_lock); + + for (slot = 0; slot < src->num_links; slot++) + if (src->links[slot] == dst) + break; + + if (WARN_ON(slot == src->num_links)) { + ret = -ENXIO; + goto out; + } + + src->links[slot] = src->links[--src->num_links]; + + new = krealloc(src->links, src->num_links * sizeof(*src->links), + GFP_KERNEL); + if (new) + src->links = new; + +out: + mutex_unlock(&icc_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(icc_link_destroy); + +/** + * icc_node_add() - add interconnect node to interconnect provider + * @node: pointer to the interconnect node + * @provider: pointer to the interconnect provider + */ +void icc_node_add(struct icc_node *node, struct icc_provider *provider) +{ + mutex_lock(&icc_lock); + + node->provider = provider; + list_add_tail(&node->node_list, &provider->nodes); + + mutex_unlock(&icc_lock); +} +EXPORT_SYMBOL_GPL(icc_node_add); + +/** + * icc_node_del() - delete interconnect node from interconnect provider + * @node: pointer to the interconnect node + */ +void icc_node_del(struct icc_node *node) +{ + mutex_lock(&icc_lock); + + list_del(&node->node_list); + + mutex_unlock(&icc_lock); +} +EXPORT_SYMBOL_GPL(icc_node_del); + +/** + * icc_provider_add() - add a new interconnect provider + * @provider: the interconnect provider that will be added into topology + * + * Return: 0 on success, or an error code otherwise + */ +int icc_provider_add(struct icc_provider *provider) +{ + if (WARN_ON(!provider->set)) + return -EINVAL; + if (WARN_ON(!provider->xlate)) + return -EINVAL; + + mutex_lock(&icc_lock); + + INIT_LIST_HEAD(&provider->nodes); + list_add_tail(&provider->provider_list, &icc_providers); + + mutex_unlock(&icc_lock); + + dev_dbg(provider->dev, "interconnect provider added to topology\n"); + + return 0; +} +EXPORT_SYMBOL_GPL(icc_provider_add); + +/** + * icc_provider_del() - delete previously added interconnect provider + * @provider: the interconnect provider that will be removed from topology + * + * Return: 0 on success, or an error code otherwise + */ +int icc_provider_del(struct icc_provider *provider) +{ + mutex_lock(&icc_lock); + if (provider->users) { + pr_warn("interconnect provider still has %d users\n", + provider->users); + mutex_unlock(&icc_lock); + return -EBUSY; + } + + if (!list_empty(&provider->nodes)) { + pr_warn("interconnect provider still has nodes\n"); + mutex_unlock(&icc_lock); + return -EBUSY; + } + + list_del(&provider->provider_list); + mutex_unlock(&icc_lock); + + return 0; +} +EXPORT_SYMBOL_GPL(icc_provider_del); + +static int __init icc_init(void) +{ + icc_debugfs_dir = debugfs_create_dir("interconnect", NULL); + debugfs_create_file("interconnect_summary", 0444, + icc_debugfs_dir, NULL, &icc_summary_fops); + return 0; +} + +static void __exit icc_exit(void) +{ + debugfs_remove_recursive(icc_debugfs_dir); +} +module_init(icc_init); +module_exit(icc_exit); + +MODULE_AUTHOR("Georgi Djakov <georgi.djakov@linaro.org>"); +MODULE_DESCRIPTION("Interconnect Driver Core"); +MODULE_LICENSE("GPL v2"); |