drivers/gpu/drm/drm_sysfs.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2
   3 /*
   4  * drm_sysfs.c - Modifications to drm_sysfs_class.c to support
   5  *               extra sysfs attribute from DRM. Normal drm_sysfs_class
   6  *               does not allow adding attributes.
   7  *
   8  * Copyright (c) 2004 Jon Smirl <jonsmirl@gmail.com>
   9  * Copyright (c) 2003-2004 Greg Kroah-Hartman <greg@kroah.com>
  10  * Copyright (c) 2003-2004 IBM Corp.
  11  */
  12
  13 #include <linux/device.h>
  14 #include <linux/err.h>
  15 #include <linux/export.h>
  16 #include <linux/gfp.h>
  17 #include <linux/i2c.h>
  18 #include <linux/kdev_t.h>
  19 #include <linux/slab.h>
  20
  21 #include <drm/drm_connector.h>
  22 #include <drm/drm_device.h>
  23 #include <drm/drm_file.h>
  24 #include <drm/drm_modes.h>
  25 #include <drm/drm_print.h>
  26 #include <drm/drm_property.h>
  27 #include <drm/drm_sysfs.h>
  28
  29 #include "drm_internal.h"
  30 #include "drm_crtc_internal.h"
  31
  32 #define to_drm_minor(d) dev_get_drvdata(d)
  33 #define to_drm_connector(d) dev_get_drvdata(d)
  34
  35 /**
  36  * DOC: overview
  37  *
  38  * DRM provides very little additional support to drivers for sysfs
  39  * interactions, beyond just all the standard stuff. Drivers who want to expose
  40  * additional sysfs properties and property groups can attach them at either
  41  * &drm_device.dev or &drm_connector.kdev.
  42  *
  43  * Registration is automatically handled when calling drm_dev_register(), or
  44  * drm_connector_register() in case of hot-plugged connectors. Unregistration is
  45  * also automatically handled by drm_dev_unregister() and
  46  * drm_connector_unregister().
  47  */
  48
  49 static struct device_type drm_sysfs_device_minor = {
  50         .name = "drm_minor"
  51 };
  52
  53 struct class *drm_class;
  54
  55 static char *drm_devnode(struct device *dev, umode_t *mode)
  56 {
  57         return kasprintf(GFP_KERNEL, "dri/%s", dev_name(dev));
  58 }
  59
  60 static CLASS_ATTR_STRING(version, S_IRUGO, "drm 1.1.0 20060810");
  61
  62 /**
  63  * drm_sysfs_init - initialize sysfs helpers
  64  *
  65  * This is used to create the DRM class, which is the implicit parent of any
  66  * other top-level DRM sysfs objects.
  67  *
  68  * You must call drm_sysfs_destroy() to release the allocated resources.
  69  *
  70  * Return: 0 on success, negative error code on failure.
  71  */
  72 int drm_sysfs_init(void)
  73 {
  74         int err;
  75
  76         drm_class = class_create(THIS_MODULE, "drm");
  77         if (IS_ERR(drm_class))
  78                 return PTR_ERR(drm_class);
  79
  80         err = class_create_file(drm_class, &class_attr_version.attr);
  81         if (err) {
  82                 class_destroy(drm_class);
  83                 drm_class = NULL;
  84                 return err;
  85         }
  86
  87         drm_class->devnode = drm_devnode;
  88         return 0;
  89 }
  90
  91 /**
  92  * drm_sysfs_destroy - destroys DRM class
  93  *
  94  * Destroy the DRM device class.
  95  */
  96 void drm_sysfs_destroy(void)
  97 {
  98         if (IS_ERR_OR_NULL(drm_class))
  99                 return;
 100         class_remove_file(drm_class, &class_attr_version.attr);
 101         class_destroy(drm_class);
 102         drm_class = NULL;
 103 }
 104
 105 /*
 106  * Connector properties
 107  */
 108 static ssize_t status_store(struct device *device,
 109                            struct device_attribute *attr,
 110                            const char *buf, size_t count)
 111 {
 112         struct drm_connector *connector = to_drm_connector(device);
 113         struct drm_device *dev = connector->dev;
 114         enum drm_connector_force old_force;
 115         int ret;
 116
 117         ret = mutex_lock_interruptible(&dev->mode_config.mutex);
 118         if (ret)
 119                 return ret;
 120
 121         old_force = connector->force;
 122
 123         if (sysfs_streq(buf, "detect"))
 124                 connector->force = 0;
 125         else if (sysfs_streq(buf, "on"))
 126                 connector->force = DRM_FORCE_ON;
 127         else if (sysfs_streq(buf, "on-digital"))
 128                 connector->force = DRM_FORCE_ON_DIGITAL;
 129         else if (sysfs_streq(buf, "off"))
 130                 connector->force = DRM_FORCE_OFF;
 131         else
 132                 ret = -EINVAL;
 133
 134         if (old_force != connector->force || !connector->force) {
 135                 DRM_DEBUG_KMS("[CONNECTOR:%d:%s] force updated from %d to %d or reprobing\n",
 136                               connector->base.id,
 137                               connector->name,
 138                               old_force, connector->force);
 139
 140                 connector->funcs->fill_modes(connector,
 141                                              dev->mode_config.max_width,
 142                                              dev->mode_config.max_height);
 143         }
 144
 145         mutex_unlock(&dev->mode_config.mutex);
 146
 147         return ret ? ret : count;
 148 }
 149
 150 static ssize_t status_show(struct device *device,
 151                            struct device_attribute *attr,
 152                            char *buf)
 153 {
 154         struct drm_connector *connector = to_drm_connector(device);
 155         enum drm_connector_status status;
 156
 157         status = READ_ONCE(connector->status);
 158
 159         return snprintf(buf, PAGE_SIZE, "%s\n",
 160                         drm_get_connector_status_name(status));
 161 }
 162
 163 static ssize_t dpms_show(struct device *device,
 164                            struct device_attribute *attr,
 165                            char *buf)
 166 {
 167         struct drm_connector *connector = to_drm_connector(device);
 168         int dpms;
 169
 170         dpms = READ_ONCE(connector->dpms);
 171
 172         return snprintf(buf, PAGE_SIZE, "%s\n",
 173                         drm_get_dpms_name(dpms));
 174 }
 175
 176 static ssize_t enabled_show(struct device *device,
 177                             struct device_attribute *attr,
 178                            char *buf)
 179 {
 180         struct drm_connector *connector = to_drm_connector(device);
 181         bool enabled;
 182
 183         enabled = READ_ONCE(connector->encoder);
 184
 185         return snprintf(buf, PAGE_SIZE, enabled ? "enabled\n" : "disabled\n");
 186 }
 187
 188 static ssize_t edid_show(struct file *filp, struct kobject *kobj,
 189                          struct bin_attribute *attr, char *buf, loff_t off,
 190                          size_t count)
 191 {
 192         struct device *connector_dev = kobj_to_dev(kobj);
 193         struct drm_connector *connector = to_drm_connector(connector_dev);
 194         unsigned char *edid;
 195         size_t size;
 196         ssize_t ret = 0;
 197
 198         mutex_lock(&connector->dev->mode_config.mutex);
 199         if (!connector->edid_blob_ptr)
 200                 goto unlock;
 201
 202         edid = connector->edid_blob_ptr->data;
 203         size = connector->edid_blob_ptr->length;
 204         if (!edid)
 205                 goto unlock;
 206
 207         if (off >= size)
 208                 goto unlock;
 209
 210         if (off + count > size)
 211                 count = size - off;
 212         memcpy(buf, edid + off, count);
 213
 214         ret = count;
 215 unlock:
 216         mutex_unlock(&connector->dev->mode_config.mutex);
 217
 218         return ret;
 219 }
 220
 221 static ssize_t modes_show(struct device *device,
 222                            struct device_attribute *attr,
 223                            char *buf)
 224 {
 225         struct drm_connector *connector = to_drm_connector(device);
 226         struct drm_display_mode *mode;
 227         int written = 0;
 228
 229         mutex_lock(&connector->dev->mode_config.mutex);
 230         list_for_each_entry(mode, &connector->modes, head) {
 231                 written += scnprintf(buf + written, PAGE_SIZE - written, "%s\n",
 232                                     mode->name);
 233         }
 234         mutex_unlock(&connector->dev->mode_config.mutex);
 235
 236         return written;
 237 }
 238
 239 static DEVICE_ATTR_RW(status);
 240 static DEVICE_ATTR_RO(enabled);
 241 static DEVICE_ATTR_RO(dpms);
 242 static DEVICE_ATTR_RO(modes);
 243
 244 static struct attribute *connector_dev_attrs[] = {
 245         &dev_attr_status.attr,
 246         &dev_attr_enabled.attr,
 247         &dev_attr_dpms.attr,
 248         &dev_attr_modes.attr,
 249         NULL
 250 };
 251
 252 static struct bin_attribute edid_attr = {
 253         .attr.name = "edid",
 254         .attr.mode = 0444,
 255         .size = 0,
 256         .read = edid_show,
 257 };
 258
 259 static struct bin_attribute *connector_bin_attrs[] = {
 260         &edid_attr,
 261         NULL
 262 };
 263
 264 static const struct attribute_group connector_dev_group = {
 265         .attrs = connector_dev_attrs,
 266         .bin_attrs = connector_bin_attrs,
 267 };
 268
 269 static const struct attribute_group *connector_dev_groups[] = {
 270         &connector_dev_group,
 271         NULL
 272 };
 273
 274 int drm_sysfs_connector_add(struct drm_connector *connector)
 275 {
 276         struct drm_device *dev = connector->dev;
 277
 278         if (connector->kdev)
 279                 return 0;
 280
 281         connector->kdev =
 282                 device_create_with_groups(drm_class, dev->primary->kdev, 0,
 283                                           connector, connector_dev_groups,
 284                                           "card%d-%s", dev->primary->index,
 285                                           connector->name);
 286         DRM_DEBUG("adding \"%s\" to sysfs\n",
 287                   connector->name);
 288
 289         if (IS_ERR(connector->kdev)) {
 290                 DRM_ERROR("failed to register connector device: %ld\n", PTR_ERR(connector->kdev));
 291                 return PTR_ERR(connector->kdev);
 292         }
 293
 294         /* Let userspace know we have a new connector */
 295         drm_sysfs_hotplug_event(dev);
 296
 297         if (connector->ddc)
 298                 return sysfs_create_link(&connector->kdev->kobj,
 299                                  &connector->ddc->dev.kobj, "ddc");
 300         return 0;
 301 }
 302
 303 void drm_sysfs_connector_remove(struct drm_connector *connector)
 304 {
 305         if (!connector->kdev)
 306                 return;
 307
 308         if (connector->ddc)
 309                 sysfs_remove_link(&connector->kdev->kobj, "ddc");
 310
 311         DRM_DEBUG("removing \"%s\" from sysfs\n",
 312                   connector->name);
 313
 314         device_unregister(connector->kdev);
 315         connector->kdev = NULL;
 316 }
 317
 318 void drm_sysfs_lease_event(struct drm_device *dev)
 319 {
 320         char *event_string = "LEASE=1";
 321         char *envp[] = { event_string, NULL };
 322
 323         DRM_DEBUG("generating lease event\n");
 324
 325         kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
 326 }
 327
 328 /**
 329  * drm_sysfs_hotplug_event - generate a DRM uevent
 330  * @dev: DRM device
 331  *
 332  * Send a uevent for the DRM device specified by @dev.  Currently we only
 333  * set HOTPLUG=1 in the uevent environment, but this could be expanded to
 334  * deal with other types of events.
 335  *
 336  * Any new uapi should be using the drm_sysfs_connector_status_event()
 337  * for uevents on connector status change.
 338  */
 339 void drm_sysfs_hotplug_event(struct drm_device *dev)
 340 {
 341         char *event_string = "HOTPLUG=1";
 342         char *envp[] = { event_string, NULL };
 343
 344         DRM_DEBUG("generating hotplug event\n");
 345
 346         kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
 347 }
 348 EXPORT_SYMBOL(drm_sysfs_hotplug_event);
 349
 350 /**
 351  * drm_sysfs_connector_status_event - generate a DRM uevent for connector
 352  * property status change
 353  * @connector: connector on which property status changed
 354  * @property: connector property whose status changed.
 355  *
 356  * Send a uevent for the DRM device specified by @dev.  Currently we
 357  * set HOTPLUG=1 and connector id along with the attached property id
 358  * related to the status change.
 359  */
 360 void drm_sysfs_connector_status_event(struct drm_connector *connector,
 361                                       struct drm_property *property)
 362 {
 363         struct drm_device *dev = connector->dev;
 364         char hotplug_str[] = "HOTPLUG=1", conn_id[21], prop_id[21];
 365         char *envp[4] = { hotplug_str, conn_id, prop_id, NULL };
 366
 367         WARN_ON(!drm_mode_obj_find_prop_id(&connector->base,
 368                                            property->base.id));
 369
 370         snprintf(conn_id, ARRAY_SIZE(conn_id),
 371                  "CONNECTOR=%u", connector->base.id);
 372         snprintf(prop_id, ARRAY_SIZE(prop_id),
 373                  "PROPERTY=%u", property->base.id);
 374
 375         DRM_DEBUG("generating connector status event\n");
 376
 377         kobject_uevent_env(&dev->primary->kdev->kobj, KOBJ_CHANGE, envp);
 378 }
 379 EXPORT_SYMBOL(drm_sysfs_connector_status_event);
 380
 381 static void drm_sysfs_release(struct device *dev)
 382 {
 383         kfree(dev);
 384 }
 385
 386 struct device *drm_sysfs_minor_alloc(struct drm_minor *minor)
 387 {
 388         const char *minor_str;
 389         struct device *kdev;
 390         int r;
 391
 392         if (minor->type == DRM_MINOR_RENDER)
 393                 minor_str = "renderD%d";
 394         else
 395                 minor_str = "card%d";
 396
 397         kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
 398         if (!kdev)
 399                 return ERR_PTR(-ENOMEM);
 400
 401         device_initialize(kdev);
 402         kdev->devt = MKDEV(DRM_MAJOR, minor->index);
 403         kdev->class = drm_class;
 404         kdev->type = &drm_sysfs_device_minor;
 405         kdev->parent = minor->dev->dev;
 406         kdev->release = drm_sysfs_release;
 407         dev_set_drvdata(kdev, minor);
 408
 409         r = dev_set_name(kdev, minor_str, minor->index);
 410         if (r < 0)
 411                 goto err_free;
 412
 413         return kdev;
 414
 415 err_free:
 416         put_device(kdev);
 417         return ERR_PTR(r);
 418 }
 419
 420 /**
 421  * drm_class_device_register - register new device with the DRM sysfs class
 422  * @dev: device to register
 423  *
 424  * Registers a new &struct device within the DRM sysfs class. Essentially only
 425  * used by ttm to have a place for its global settings. Drivers should never use
 426  * this.
 427  */
 428 int drm_class_device_register(struct device *dev)
 429 {
 430         if (!drm_class || IS_ERR(drm_class))
 431                 return -ENOENT;
 432
 433         dev->class = drm_class;
 434         return device_register(dev);
 435 }
 436 EXPORT_SYMBOL_GPL(drm_class_device_register);
 437
 438 /**
 439  * drm_class_device_unregister - unregister device with the DRM sysfs class
 440  * @dev: device to unregister
 441  *
 442  * Unregisters a &struct device from the DRM sysfs class. Essentially only used
 443  * by ttm to have a place for its global settings. Drivers should never use
 444  * this.
 445  */
 446 void drm_class_device_unregister(struct device *dev)
 447 {
 448         return device_unregister(dev);
 449 }
 450 EXPORT_SYMBOL_GPL(drm_class_device_unregister);