summaryrefslogtreecommitdiffstats
path: root/drivers/hwtracing/coresight/coresight-sysfs.c
blob: 34d2a2d31d003b0468c0b8715338c3e9dcf7c1ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
// 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;
}
EXPORT_SYMBOL_GPL(coresight_add_sysfs_link);

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--;
}
EXPORT_SYMBOL_GPL(coresight_remove_sysfs_link);

/*
 * 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;
}