blob: ac9ffe2752d12bf2eef6822603daf39ca56a34c1 [file] [log] [blame]
// 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>
#include "internal.h"
#define CREATE_TRACE_POINTS
#include "trace.h"
static DEFINE_IDR(icc_idr);
static LIST_HEAD(icc_providers);
static DEFINE_MUTEX(icc_lock);
static struct dentry *icc_debugfs_dir;
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;
}
DEFINE_SHOW_ATTRIBUTE(icc_summary);
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;
if (p->pre_aggregate)
p->pre_aggregate(node);
hlist_for_each_entry(r, &node->req_list, req_node)
p->aggregate(node, r->tag, 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);
mutex_unlock(&icc_lock);
if (IS_ERR(path)) {
dev_err(dev, "%s: invalid path=%ld\n", __func__, PTR_ERR(path));
return path;
}
if (name)
path->name = kstrdup_const(name, GFP_KERNEL);
else
path->name = kasprintf(GFP_KERNEL, "%s-%s",
src_node->name, dst_node->name);
if (!path->name) {
kfree(path);
return ERR_PTR(-ENOMEM);
}
return path;
}
EXPORT_SYMBOL_GPL(of_icc_get);
/**
* icc_set_tag() - set an optional tag on a path
* @path: the path we want to tag
* @tag: the tag value
*
* This function allows consumers to append a tag to the requests associated
* with a path, so that a different aggregation could be done based on this tag.
*/
void icc_set_tag(struct icc_path *path, u32 tag)
{
int i;
if (!path)
return;
mutex_lock(&icc_lock);
for (i = 0; i < path->num_nodes; i++)
path->reqs[i].tag = tag;
mutex_unlock(&icc_lock);
}
EXPORT_SYMBOL_GPL(icc_set_tag);
/**
* 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);
trace_icc_set_bw(path, node, i, avg_bw, peak_bw);
}
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);
trace_icc_set_bw_end(path, ret);
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));
goto out;
}
path->name = kasprintf(GFP_KERNEL, "%s-%s", src->name, dst->name);
if (!path->name) {
kfree(path);
path = ERR_PTR(-ENOMEM);
}
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_const(path->name);
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");