1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (c) 2019, Linaro Limited, All rights reserved. 4 * Author: Mike Leach <mike.leach@linaro.org> 5 */ 6 7 #include <linux/device.h> 8 #include <linux/kernel.h> 9 10 #include "coresight-priv.h" 11 12 /* 13 * Connections group - links attribute. 14 * Count of created links between coresight components in the group. 15 */ 16 static ssize_t nr_links_show(struct device *dev, 17 struct device_attribute *attr, 18 char *buf) 19 { 20 struct coresight_device *csdev = to_coresight_device(dev); 21 22 return sprintf(buf, "%d\n", csdev->nr_links); 23 } 24 static DEVICE_ATTR_RO(nr_links); 25 26 static struct attribute *coresight_conns_attrs[] = { 27 &dev_attr_nr_links.attr, 28 NULL, 29 }; 30 31 static struct attribute_group coresight_conns_group = { 32 .attrs = coresight_conns_attrs, 33 .name = "connections", 34 }; 35 36 /* 37 * Create connections group for CoreSight devices. 38 * This group will then be used to collate the sysfs links between 39 * devices. 40 */ 41 int coresight_create_conns_sysfs_group(struct coresight_device *csdev) 42 { 43 int ret = 0; 44 45 if (!csdev) 46 return -EINVAL; 47 48 ret = sysfs_create_group(&csdev->dev.kobj, &coresight_conns_group); 49 if (ret) 50 return ret; 51 52 csdev->has_conns_grp = true; 53 return ret; 54 } 55 56 void coresight_remove_conns_sysfs_group(struct coresight_device *csdev) 57 { 58 if (!csdev) 59 return; 60 61 if (csdev->has_conns_grp) { 62 sysfs_remove_group(&csdev->dev.kobj, &coresight_conns_group); 63 csdev->has_conns_grp = false; 64 } 65 } 66 67 int coresight_add_sysfs_link(struct coresight_sysfs_link *info) 68 { 69 int ret = 0; 70 71 if (!info) 72 return -EINVAL; 73 if (!info->orig || !info->target || 74 !info->orig_name || !info->target_name) 75 return -EINVAL; 76 if (!info->orig->has_conns_grp || !info->target->has_conns_grp) 77 return -EINVAL; 78 79 /* first link orig->target */ 80 ret = sysfs_add_link_to_group(&info->orig->dev.kobj, 81 coresight_conns_group.name, 82 &info->target->dev.kobj, 83 info->orig_name); 84 if (ret) 85 return ret; 86 87 /* second link target->orig */ 88 ret = sysfs_add_link_to_group(&info->target->dev.kobj, 89 coresight_conns_group.name, 90 &info->orig->dev.kobj, 91 info->target_name); 92 93 /* error in second link - remove first - otherwise inc counts */ 94 if (ret) { 95 sysfs_remove_link_from_group(&info->orig->dev.kobj, 96 coresight_conns_group.name, 97 info->orig_name); 98 } else { 99 info->orig->nr_links++; 100 info->target->nr_links++; 101 } 102 103 return ret; 104 } 105 EXPORT_SYMBOL_GPL(coresight_add_sysfs_link); 106 107 void coresight_remove_sysfs_link(struct coresight_sysfs_link *info) 108 { 109 if (!info) 110 return; 111 if (!info->orig || !info->target || 112 !info->orig_name || !info->target_name) 113 return; 114 115 sysfs_remove_link_from_group(&info->orig->dev.kobj, 116 coresight_conns_group.name, 117 info->orig_name); 118 119 sysfs_remove_link_from_group(&info->target->dev.kobj, 120 coresight_conns_group.name, 121 info->target_name); 122 123 info->orig->nr_links--; 124 info->target->nr_links--; 125 } 126 EXPORT_SYMBOL_GPL(coresight_remove_sysfs_link); 127 128 /* 129 * coresight_make_links: Make a link for a connection from a @orig 130 * device to @target, represented by @conn. 131 * 132 * e.g, for devOrig[output_X] -> devTarget[input_Y] is represented 133 * as two symbolic links : 134 * 135 * /sys/.../devOrig/out:X -> /sys/.../devTarget/ 136 * /sys/.../devTarget/in:Y -> /sys/.../devOrig/ 137 * 138 * The link names are allocated for a device where it appears. i.e, the 139 * "out" link on the master and "in" link on the slave device. 140 * The link info is stored in the connection record for avoiding 141 * the reconstruction of names for removal. 142 */ 143 int coresight_make_links(struct coresight_device *orig, 144 struct coresight_connection *conn, 145 struct coresight_device *target) 146 { 147 int ret = -ENOMEM; 148 char *outs = NULL, *ins = NULL; 149 struct coresight_sysfs_link *link = NULL; 150 151 /* Helper devices aren't shown in sysfs */ 152 if (conn->dest_port == -1 && conn->src_port == -1) 153 return 0; 154 155 do { 156 outs = devm_kasprintf(&orig->dev, GFP_KERNEL, 157 "out:%d", conn->src_port); 158 if (!outs) 159 break; 160 ins = devm_kasprintf(&target->dev, GFP_KERNEL, 161 "in:%d", conn->dest_port); 162 if (!ins) 163 break; 164 link = devm_kzalloc(&orig->dev, 165 sizeof(struct coresight_sysfs_link), 166 GFP_KERNEL); 167 if (!link) 168 break; 169 170 link->orig = orig; 171 link->target = target; 172 link->orig_name = outs; 173 link->target_name = ins; 174 175 ret = coresight_add_sysfs_link(link); 176 if (ret) 177 break; 178 179 conn->link = link; 180 return 0; 181 } while (0); 182 183 return ret; 184 } 185 186 /* 187 * coresight_remove_links: Remove the sysfs links for a given connection @conn, 188 * from @orig device to @target device. See coresight_make_links() for more 189 * details. 190 */ 191 void coresight_remove_links(struct coresight_device *orig, 192 struct coresight_connection *conn) 193 { 194 if (!orig || !conn->link) 195 return; 196 197 coresight_remove_sysfs_link(conn->link); 198 199 devm_kfree(&conn->dest_dev->dev, conn->link->target_name); 200 devm_kfree(&orig->dev, conn->link->orig_name); 201 devm_kfree(&orig->dev, conn->link); 202 conn->link = NULL; 203 } 204