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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2019, Linaro Limited, All rights reserved.
* Author: Mike Leach <mike.leach@linaro.org>
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include "coresight-priv.h"
/*
* Connections group - links attribute.
* Count of created links between coresight components in the group.
*/
static ssize_t nr_links_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct coresight_device *csdev = to_coresight_device(dev);
return sprintf(buf, "%d\n", csdev->nr_links);
}
static DEVICE_ATTR_RO(nr_links);
static struct attribute *coresight_conns_attrs[] = {
&dev_attr_nr_links.attr,
NULL,
};
static struct attribute_group coresight_conns_group = {
.attrs = coresight_conns_attrs,
.name = "connections",
};
/*
* Create connections group for CoreSight devices.
* This group will then be used to collate the sysfs links between
* devices.
*/
int coresight_create_conns_sysfs_group(struct coresight_device *csdev)
{
int ret = 0;
if (!csdev)
return -EINVAL;
ret = sysfs_create_group(&csdev->dev.kobj, &coresight_conns_group);
if (ret)
return ret;
csdev->has_conns_grp = true;
return ret;
}
void coresight_remove_conns_sysfs_group(struct coresight_device *csdev)
{
if (!csdev)
return;
if (csdev->has_conns_grp) {
sysfs_remove_group(&csdev->dev.kobj, &coresight_conns_group);
csdev->has_conns_grp = false;
}
}
int coresight_add_sysfs_link(struct coresight_sysfs_link *info)
{
int ret = 0;
if (!info)
return -EINVAL;
if (!info->orig || !info->target ||
!info->orig_name || !info->target_name)
return -EINVAL;
if (!info->orig->has_conns_grp || !info->target->has_conns_grp)
return -EINVAL;
/* first link orig->target */
ret = sysfs_add_link_to_group(&info->orig->dev.kobj,
coresight_conns_group.name,
&info->target->dev.kobj,
info->orig_name);
if (ret)
return ret;
/* second link target->orig */
ret = sysfs_add_link_to_group(&info->target->dev.kobj,
coresight_conns_group.name,
&info->orig->dev.kobj,
info->target_name);
/* error in second link - remove first - otherwise inc counts */
if (ret) {
sysfs_remove_link_from_group(&info->orig->dev.kobj,
coresight_conns_group.name,
info->orig_name);
} else {
info->orig->nr_links++;
info->target->nr_links++;
}
return ret;
}
void coresight_remove_sysfs_link(struct coresight_sysfs_link *info)
{
if (!info)
return;
if (!info->orig || !info->target ||
!info->orig_name || !info->target_name)
return;
sysfs_remove_link_from_group(&info->orig->dev.kobj,
coresight_conns_group.name,
info->orig_name);
sysfs_remove_link_from_group(&info->target->dev.kobj,
coresight_conns_group.name,
info->target_name);
info->orig->nr_links--;
info->target->nr_links--;
}
/*
* coresight_make_links: Make a link for a connection from a @orig
* device to @target, represented by @conn.
*
* e.g, for devOrig[output_X] -> devTarget[input_Y] is represented
* as two symbolic links :
*
* /sys/.../devOrig/out:X -> /sys/.../devTarget/
* /sys/.../devTarget/in:Y -> /sys/.../devOrig/
*
* The link names are allocated for a device where it appears. i.e, the
* "out" link on the master and "in" link on the slave device.
* The link info is stored in the connection record for avoiding
* the reconstruction of names for removal.
*/
int coresight_make_links(struct coresight_device *orig,
struct coresight_connection *conn,
struct coresight_device *target)
{
int ret = -ENOMEM;
char *outs = NULL, *ins = NULL;
struct coresight_sysfs_link *link = NULL;
do {
outs = devm_kasprintf(&orig->dev, GFP_KERNEL,
"out:%d", conn->outport);
if (!outs)
break;
ins = devm_kasprintf(&target->dev, GFP_KERNEL,
"in:%d", conn->child_port);
if (!ins)
break;
link = devm_kzalloc(&orig->dev,
sizeof(struct coresight_sysfs_link),
GFP_KERNEL);
if (!link)
break;
link->orig = orig;
link->target = target;
link->orig_name = outs;
link->target_name = ins;
ret = coresight_add_sysfs_link(link);
if (ret)
break;
conn->link = link;
/*
* Install the device connection. This also indicates that
* the links are operational on both ends.
*/
conn->child_dev = target;
return 0;
} while (0);
return ret;
}
/*
* coresight_remove_links: Remove the sysfs links for a given connection @conn,
* from @orig device to @target device. See coresight_make_links() for more
* details.
*/
void coresight_remove_links(struct coresight_device *orig,
struct coresight_connection *conn)
{
if (!orig || !conn->link)
return;
coresight_remove_sysfs_link(conn->link);
devm_kfree(&conn->child_dev->dev, conn->link->target_name);
devm_kfree(&orig->dev, conn->link->orig_name);
devm_kfree(&orig->dev, conn->link);
conn->link = NULL;
conn->child_dev = NULL;
}
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