1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * cec-core.c - HDMI Consumer Electronics Control framework - Core 4 * 5 * Copyright 2016 Cisco Systems, Inc. and/or its affiliates. All rights reserved. 6 */ 7 8 #include <linux/errno.h> 9 #include <linux/init.h> 10 #include <linux/module.h> 11 #include <linux/kernel.h> 12 #include <linux/kmod.h> 13 #include <linux/slab.h> 14 #include <linux/mm.h> 15 #include <linux/string.h> 16 #include <linux/types.h> 17 18 #include "cec-priv.h" 19 20 #define CEC_NUM_DEVICES 256 21 #define CEC_NAME "cec" 22 23 int cec_debug; 24 module_param_named(debug, cec_debug, int, 0644); 25 MODULE_PARM_DESC(debug, "debug level (0-2)"); 26 27 static bool debug_phys_addr; 28 module_param(debug_phys_addr, bool, 0644); 29 MODULE_PARM_DESC(debug_phys_addr, "add CEC_CAP_PHYS_ADDR if set"); 30 31 static dev_t cec_dev_t; 32 33 /* Active devices */ 34 static DEFINE_MUTEX(cec_devnode_lock); 35 static DECLARE_BITMAP(cec_devnode_nums, CEC_NUM_DEVICES); 36 37 static struct dentry *top_cec_dir; 38 39 /* dev to cec_devnode */ 40 #define to_cec_devnode(cd) container_of(cd, struct cec_devnode, dev) 41 42 int cec_get_device(struct cec_devnode *devnode) 43 { 44 /* 45 * Check if the cec device is available. This needs to be done with 46 * the devnode->lock held to prevent an open/unregister race: 47 * without the lock, the device could be unregistered and freed between 48 * the devnode->registered check and get_device() calls, leading to 49 * a crash. 50 */ 51 mutex_lock(&devnode->lock); 52 /* 53 * return ENXIO if the cec device has been removed 54 * already or if it is not registered anymore. 55 */ 56 if (!devnode->registered) { 57 mutex_unlock(&devnode->lock); 58 return -ENXIO; 59 } 60 /* and increase the device refcount */ 61 get_device(&devnode->dev); 62 mutex_unlock(&devnode->lock); 63 return 0; 64 } 65 66 void cec_put_device(struct cec_devnode *devnode) 67 { 68 put_device(&devnode->dev); 69 } 70 71 /* Called when the last user of the cec device exits. */ 72 static void cec_devnode_release(struct device *cd) 73 { 74 struct cec_devnode *devnode = to_cec_devnode(cd); 75 76 mutex_lock(&cec_devnode_lock); 77 /* Mark device node number as free */ 78 clear_bit(devnode->minor, cec_devnode_nums); 79 mutex_unlock(&cec_devnode_lock); 80 81 cec_delete_adapter(to_cec_adapter(devnode)); 82 } 83 84 static struct bus_type cec_bus_type = { 85 .name = CEC_NAME, 86 }; 87 88 /* 89 * Register a cec device node 90 * 91 * The registration code assigns minor numbers and registers the new device node 92 * with the kernel. An error is returned if no free minor number can be found, 93 * or if the registration of the device node fails. 94 * 95 * Zero is returned on success. 96 * 97 * Note that if the cec_devnode_register call fails, the release() callback of 98 * the cec_devnode structure is *not* called, so the caller is responsible for 99 * freeing any data. 100 */ 101 static int __must_check cec_devnode_register(struct cec_devnode *devnode, 102 struct module *owner) 103 { 104 int minor; 105 int ret; 106 107 /* Part 1: Find a free minor number */ 108 mutex_lock(&cec_devnode_lock); 109 minor = find_first_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES); 110 if (minor == CEC_NUM_DEVICES) { 111 mutex_unlock(&cec_devnode_lock); 112 pr_err("could not get a free minor\n"); 113 return -ENFILE; 114 } 115 116 set_bit(minor, cec_devnode_nums); 117 mutex_unlock(&cec_devnode_lock); 118 119 devnode->minor = minor; 120 devnode->dev.bus = &cec_bus_type; 121 devnode->dev.devt = MKDEV(MAJOR(cec_dev_t), minor); 122 devnode->dev.release = cec_devnode_release; 123 dev_set_name(&devnode->dev, "cec%d", devnode->minor); 124 device_initialize(&devnode->dev); 125 126 /* Part 2: Initialize and register the character device */ 127 cdev_init(&devnode->cdev, &cec_devnode_fops); 128 devnode->cdev.owner = owner; 129 kobject_set_name(&devnode->cdev.kobj, "cec%d", devnode->minor); 130 131 devnode->registered = true; 132 ret = cdev_device_add(&devnode->cdev, &devnode->dev); 133 if (ret) { 134 devnode->registered = false; 135 pr_err("%s: cdev_device_add failed\n", __func__); 136 goto clr_bit; 137 } 138 139 return 0; 140 141 clr_bit: 142 mutex_lock(&cec_devnode_lock); 143 clear_bit(devnode->minor, cec_devnode_nums); 144 mutex_unlock(&cec_devnode_lock); 145 return ret; 146 } 147 148 /* 149 * Unregister a cec device node 150 * 151 * This unregisters the passed device. Future open calls will be met with 152 * errors. 153 * 154 * This function can safely be called if the device node has never been 155 * registered or has already been unregistered. 156 */ 157 static void cec_devnode_unregister(struct cec_adapter *adap) 158 { 159 struct cec_devnode *devnode = &adap->devnode; 160 struct cec_fh *fh; 161 162 mutex_lock(&devnode->lock); 163 164 /* Check if devnode was never registered or already unregistered */ 165 if (!devnode->registered || devnode->unregistered) { 166 mutex_unlock(&devnode->lock); 167 return; 168 } 169 devnode->registered = false; 170 devnode->unregistered = true; 171 172 mutex_lock(&devnode->lock_fhs); 173 list_for_each_entry(fh, &devnode->fhs, list) 174 wake_up_interruptible(&fh->wait); 175 mutex_unlock(&devnode->lock_fhs); 176 177 mutex_unlock(&devnode->lock); 178 179 mutex_lock(&adap->lock); 180 __cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false); 181 __cec_s_log_addrs(adap, NULL, false); 182 mutex_unlock(&adap->lock); 183 184 cdev_device_del(&devnode->cdev, &devnode->dev); 185 put_device(&devnode->dev); 186 } 187 188 #ifdef CONFIG_DEBUG_FS 189 static ssize_t cec_error_inj_write(struct file *file, 190 const char __user *ubuf, size_t count, loff_t *ppos) 191 { 192 struct seq_file *sf = file->private_data; 193 struct cec_adapter *adap = sf->private; 194 char *buf; 195 char *line; 196 char *p; 197 198 buf = memdup_user_nul(ubuf, min_t(size_t, PAGE_SIZE, count)); 199 if (IS_ERR(buf)) 200 return PTR_ERR(buf); 201 p = buf; 202 while (p && *p) { 203 p = skip_spaces(p); 204 line = strsep(&p, "\n"); 205 if (!*line || *line == '#') 206 continue; 207 if (!adap->ops->error_inj_parse_line(adap, line)) { 208 kfree(buf); 209 return -EINVAL; 210 } 211 } 212 kfree(buf); 213 return count; 214 } 215 216 static int cec_error_inj_show(struct seq_file *sf, void *unused) 217 { 218 struct cec_adapter *adap = sf->private; 219 220 return adap->ops->error_inj_show(adap, sf); 221 } 222 223 static int cec_error_inj_open(struct inode *inode, struct file *file) 224 { 225 return single_open(file, cec_error_inj_show, inode->i_private); 226 } 227 228 static const struct file_operations cec_error_inj_fops = { 229 .open = cec_error_inj_open, 230 .write = cec_error_inj_write, 231 .read = seq_read, 232 .llseek = seq_lseek, 233 .release = single_release, 234 }; 235 #endif 236 237 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, 238 void *priv, const char *name, u32 caps, 239 u8 available_las) 240 { 241 struct cec_adapter *adap; 242 int res; 243 244 #ifndef CONFIG_MEDIA_CEC_RC 245 caps &= ~CEC_CAP_RC; 246 #endif 247 248 if (WARN_ON(!caps)) 249 return ERR_PTR(-EINVAL); 250 if (WARN_ON(!ops)) 251 return ERR_PTR(-EINVAL); 252 if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS)) 253 return ERR_PTR(-EINVAL); 254 adap = kzalloc(sizeof(*adap), GFP_KERNEL); 255 if (!adap) 256 return ERR_PTR(-ENOMEM); 257 strscpy(adap->name, name, sizeof(adap->name)); 258 adap->phys_addr = CEC_PHYS_ADDR_INVALID; 259 adap->cec_pin_is_high = true; 260 adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0; 261 adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE; 262 adap->capabilities = caps; 263 if (debug_phys_addr) 264 adap->capabilities |= CEC_CAP_PHYS_ADDR; 265 adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD; 266 adap->available_log_addrs = available_las; 267 adap->sequence = 0; 268 adap->ops = ops; 269 adap->priv = priv; 270 mutex_init(&adap->lock); 271 INIT_LIST_HEAD(&adap->transmit_queue); 272 INIT_LIST_HEAD(&adap->wait_queue); 273 init_waitqueue_head(&adap->kthread_waitq); 274 275 /* adap->devnode initialization */ 276 INIT_LIST_HEAD(&adap->devnode.fhs); 277 mutex_init(&adap->devnode.lock_fhs); 278 mutex_init(&adap->devnode.lock); 279 280 adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name); 281 if (IS_ERR(adap->kthread)) { 282 pr_err("cec-%s: kernel_thread() failed\n", name); 283 res = PTR_ERR(adap->kthread); 284 kfree(adap); 285 return ERR_PTR(res); 286 } 287 288 #ifdef CONFIG_MEDIA_CEC_RC 289 if (!(caps & CEC_CAP_RC)) 290 return adap; 291 292 /* Prepare the RC input device */ 293 adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE); 294 if (!adap->rc) { 295 pr_err("cec-%s: failed to allocate memory for rc_dev\n", 296 name); 297 kthread_stop(adap->kthread); 298 kfree(adap); 299 return ERR_PTR(-ENOMEM); 300 } 301 302 snprintf(adap->input_phys, sizeof(adap->input_phys), 303 "%s/input0", adap->name); 304 305 adap->rc->device_name = adap->name; 306 adap->rc->input_phys = adap->input_phys; 307 adap->rc->input_id.bustype = BUS_CEC; 308 adap->rc->input_id.vendor = 0; 309 adap->rc->input_id.product = 0; 310 adap->rc->input_id.version = 1; 311 adap->rc->driver_name = CEC_NAME; 312 adap->rc->allowed_protocols = RC_PROTO_BIT_CEC; 313 adap->rc->priv = adap; 314 adap->rc->map_name = RC_MAP_CEC; 315 adap->rc->timeout = MS_TO_US(550); 316 #endif 317 return adap; 318 } 319 EXPORT_SYMBOL_GPL(cec_allocate_adapter); 320 321 int cec_register_adapter(struct cec_adapter *adap, 322 struct device *parent) 323 { 324 int res; 325 326 if (IS_ERR_OR_NULL(adap)) 327 return 0; 328 329 if (WARN_ON(!parent)) 330 return -EINVAL; 331 332 adap->owner = parent->driver->owner; 333 adap->devnode.dev.parent = parent; 334 335 #ifdef CONFIG_MEDIA_CEC_RC 336 if (adap->capabilities & CEC_CAP_RC) { 337 adap->rc->dev.parent = parent; 338 res = rc_register_device(adap->rc); 339 340 if (res) { 341 pr_err("cec-%s: failed to prepare input device\n", 342 adap->name); 343 rc_free_device(adap->rc); 344 adap->rc = NULL; 345 return res; 346 } 347 } 348 #endif 349 350 res = cec_devnode_register(&adap->devnode, adap->owner); 351 if (res) { 352 #ifdef CONFIG_MEDIA_CEC_RC 353 /* Note: rc_unregister also calls rc_free */ 354 rc_unregister_device(adap->rc); 355 adap->rc = NULL; 356 #endif 357 return res; 358 } 359 360 dev_set_drvdata(&adap->devnode.dev, adap); 361 #ifdef CONFIG_DEBUG_FS 362 if (!top_cec_dir) 363 return 0; 364 365 adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), 366 top_cec_dir); 367 368 debugfs_create_devm_seqfile(&adap->devnode.dev, "status", adap->cec_dir, 369 cec_adap_status); 370 371 if (!adap->ops->error_inj_show || !adap->ops->error_inj_parse_line) 372 return 0; 373 debugfs_create_file("error-inj", 0644, adap->cec_dir, adap, 374 &cec_error_inj_fops); 375 #endif 376 return 0; 377 } 378 EXPORT_SYMBOL_GPL(cec_register_adapter); 379 380 void cec_unregister_adapter(struct cec_adapter *adap) 381 { 382 if (IS_ERR_OR_NULL(adap)) 383 return; 384 385 #ifdef CONFIG_MEDIA_CEC_RC 386 /* Note: rc_unregister also calls rc_free */ 387 rc_unregister_device(adap->rc); 388 adap->rc = NULL; 389 #endif 390 debugfs_remove_recursive(adap->cec_dir); 391 #ifdef CONFIG_CEC_NOTIFIER 392 cec_notifier_cec_adap_unregister(adap->notifier, adap); 393 #endif 394 cec_devnode_unregister(adap); 395 } 396 EXPORT_SYMBOL_GPL(cec_unregister_adapter); 397 398 void cec_delete_adapter(struct cec_adapter *adap) 399 { 400 if (IS_ERR_OR_NULL(adap)) 401 return; 402 if (adap->kthread_config) 403 kthread_stop(adap->kthread_config); 404 kthread_stop(adap->kthread); 405 if (adap->ops->adap_free) 406 adap->ops->adap_free(adap); 407 #ifdef CONFIG_MEDIA_CEC_RC 408 rc_free_device(adap->rc); 409 #endif 410 kfree(adap); 411 } 412 EXPORT_SYMBOL_GPL(cec_delete_adapter); 413 414 /* 415 * Initialise cec for linux 416 */ 417 static int __init cec_devnode_init(void) 418 { 419 int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME); 420 421 if (ret < 0) { 422 pr_warn("cec: unable to allocate major\n"); 423 return ret; 424 } 425 426 #ifdef CONFIG_DEBUG_FS 427 top_cec_dir = debugfs_create_dir("cec", NULL); 428 if (IS_ERR_OR_NULL(top_cec_dir)) { 429 pr_warn("cec: Failed to create debugfs cec dir\n"); 430 top_cec_dir = NULL; 431 } 432 #endif 433 434 ret = bus_register(&cec_bus_type); 435 if (ret < 0) { 436 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES); 437 pr_warn("cec: bus_register failed\n"); 438 return -EIO; 439 } 440 441 return 0; 442 } 443 444 static void __exit cec_devnode_exit(void) 445 { 446 debugfs_remove_recursive(top_cec_dir); 447 bus_unregister(&cec_bus_type); 448 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES); 449 } 450 451 subsys_initcall(cec_devnode_init); 452 module_exit(cec_devnode_exit) 453 454 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>"); 455 MODULE_DESCRIPTION("Device node registration for cec drivers"); 456 MODULE_LICENSE("GPL"); 457