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_next_zero_bit(cec_devnode_nums, CEC_NUM_DEVICES, 0); 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 list_for_each_entry(fh, &devnode->fhs, list) 173 wake_up_interruptible(&fh->wait); 174 175 mutex_unlock(&devnode->lock); 176 177 mutex_lock(&adap->lock); 178 __cec_s_phys_addr(adap, CEC_PHYS_ADDR_INVALID, false); 179 __cec_s_log_addrs(adap, NULL, false); 180 mutex_unlock(&adap->lock); 181 182 cdev_device_del(&devnode->cdev, &devnode->dev); 183 put_device(&devnode->dev); 184 } 185 186 #ifdef CONFIG_DEBUG_FS 187 static ssize_t cec_error_inj_write(struct file *file, 188 const char __user *ubuf, size_t count, loff_t *ppos) 189 { 190 struct seq_file *sf = file->private_data; 191 struct cec_adapter *adap = sf->private; 192 char *buf; 193 char *line; 194 char *p; 195 196 buf = memdup_user_nul(ubuf, min_t(size_t, PAGE_SIZE, count)); 197 if (IS_ERR(buf)) 198 return PTR_ERR(buf); 199 p = buf; 200 while (p && *p) { 201 p = skip_spaces(p); 202 line = strsep(&p, "\n"); 203 if (!*line || *line == '#') 204 continue; 205 if (!adap->ops->error_inj_parse_line(adap, line)) { 206 kfree(buf); 207 return -EINVAL; 208 } 209 } 210 kfree(buf); 211 return count; 212 } 213 214 static int cec_error_inj_show(struct seq_file *sf, void *unused) 215 { 216 struct cec_adapter *adap = sf->private; 217 218 return adap->ops->error_inj_show(adap, sf); 219 } 220 221 static int cec_error_inj_open(struct inode *inode, struct file *file) 222 { 223 return single_open(file, cec_error_inj_show, inode->i_private); 224 } 225 226 static const struct file_operations cec_error_inj_fops = { 227 .open = cec_error_inj_open, 228 .write = cec_error_inj_write, 229 .read = seq_read, 230 .llseek = seq_lseek, 231 .release = single_release, 232 }; 233 #endif 234 235 struct cec_adapter *cec_allocate_adapter(const struct cec_adap_ops *ops, 236 void *priv, const char *name, u32 caps, 237 u8 available_las) 238 { 239 struct cec_adapter *adap; 240 int res; 241 242 #ifndef CONFIG_MEDIA_CEC_RC 243 caps &= ~CEC_CAP_RC; 244 #endif 245 246 if (WARN_ON(!caps)) 247 return ERR_PTR(-EINVAL); 248 if (WARN_ON(!ops)) 249 return ERR_PTR(-EINVAL); 250 if (WARN_ON(!available_las || available_las > CEC_MAX_LOG_ADDRS)) 251 return ERR_PTR(-EINVAL); 252 adap = kzalloc(sizeof(*adap), GFP_KERNEL); 253 if (!adap) 254 return ERR_PTR(-ENOMEM); 255 strscpy(adap->name, name, sizeof(adap->name)); 256 adap->phys_addr = CEC_PHYS_ADDR_INVALID; 257 adap->cec_pin_is_high = true; 258 adap->log_addrs.cec_version = CEC_OP_CEC_VERSION_2_0; 259 adap->log_addrs.vendor_id = CEC_VENDOR_ID_NONE; 260 adap->capabilities = caps; 261 if (debug_phys_addr) 262 adap->capabilities |= CEC_CAP_PHYS_ADDR; 263 adap->needs_hpd = caps & CEC_CAP_NEEDS_HPD; 264 adap->available_log_addrs = available_las; 265 adap->sequence = 0; 266 adap->ops = ops; 267 adap->priv = priv; 268 mutex_init(&adap->lock); 269 INIT_LIST_HEAD(&adap->transmit_queue); 270 INIT_LIST_HEAD(&adap->wait_queue); 271 init_waitqueue_head(&adap->kthread_waitq); 272 273 /* adap->devnode initialization */ 274 INIT_LIST_HEAD(&adap->devnode.fhs); 275 mutex_init(&adap->devnode.lock); 276 277 adap->kthread = kthread_run(cec_thread_func, adap, "cec-%s", name); 278 if (IS_ERR(adap->kthread)) { 279 pr_err("cec-%s: kernel_thread() failed\n", name); 280 res = PTR_ERR(adap->kthread); 281 kfree(adap); 282 return ERR_PTR(res); 283 } 284 285 #ifdef CONFIG_MEDIA_CEC_RC 286 if (!(caps & CEC_CAP_RC)) 287 return adap; 288 289 /* Prepare the RC input device */ 290 adap->rc = rc_allocate_device(RC_DRIVER_SCANCODE); 291 if (!adap->rc) { 292 pr_err("cec-%s: failed to allocate memory for rc_dev\n", 293 name); 294 kthread_stop(adap->kthread); 295 kfree(adap); 296 return ERR_PTR(-ENOMEM); 297 } 298 299 snprintf(adap->input_phys, sizeof(adap->input_phys), 300 "%s/input0", adap->name); 301 302 adap->rc->device_name = adap->name; 303 adap->rc->input_phys = adap->input_phys; 304 adap->rc->input_id.bustype = BUS_CEC; 305 adap->rc->input_id.vendor = 0; 306 adap->rc->input_id.product = 0; 307 adap->rc->input_id.version = 1; 308 adap->rc->driver_name = CEC_NAME; 309 adap->rc->allowed_protocols = RC_PROTO_BIT_CEC; 310 adap->rc->priv = adap; 311 adap->rc->map_name = RC_MAP_CEC; 312 adap->rc->timeout = MS_TO_US(550); 313 #endif 314 return adap; 315 } 316 EXPORT_SYMBOL_GPL(cec_allocate_adapter); 317 318 int cec_register_adapter(struct cec_adapter *adap, 319 struct device *parent) 320 { 321 int res; 322 323 if (IS_ERR_OR_NULL(adap)) 324 return 0; 325 326 if (WARN_ON(!parent)) 327 return -EINVAL; 328 329 adap->owner = parent->driver->owner; 330 adap->devnode.dev.parent = parent; 331 332 #ifdef CONFIG_MEDIA_CEC_RC 333 if (adap->capabilities & CEC_CAP_RC) { 334 adap->rc->dev.parent = parent; 335 res = rc_register_device(adap->rc); 336 337 if (res) { 338 pr_err("cec-%s: failed to prepare input device\n", 339 adap->name); 340 rc_free_device(adap->rc); 341 adap->rc = NULL; 342 return res; 343 } 344 } 345 #endif 346 347 res = cec_devnode_register(&adap->devnode, adap->owner); 348 if (res) { 349 #ifdef CONFIG_MEDIA_CEC_RC 350 /* Note: rc_unregister also calls rc_free */ 351 rc_unregister_device(adap->rc); 352 adap->rc = NULL; 353 #endif 354 return res; 355 } 356 357 dev_set_drvdata(&adap->devnode.dev, adap); 358 #ifdef CONFIG_DEBUG_FS 359 if (!top_cec_dir) 360 return 0; 361 362 adap->cec_dir = debugfs_create_dir(dev_name(&adap->devnode.dev), 363 top_cec_dir); 364 365 debugfs_create_devm_seqfile(&adap->devnode.dev, "status", adap->cec_dir, 366 cec_adap_status); 367 368 if (!adap->ops->error_inj_show || !adap->ops->error_inj_parse_line) 369 return 0; 370 debugfs_create_file("error-inj", 0644, adap->cec_dir, adap, 371 &cec_error_inj_fops); 372 #endif 373 return 0; 374 } 375 EXPORT_SYMBOL_GPL(cec_register_adapter); 376 377 void cec_unregister_adapter(struct cec_adapter *adap) 378 { 379 if (IS_ERR_OR_NULL(adap)) 380 return; 381 382 #ifdef CONFIG_MEDIA_CEC_RC 383 /* Note: rc_unregister also calls rc_free */ 384 rc_unregister_device(adap->rc); 385 adap->rc = NULL; 386 #endif 387 debugfs_remove_recursive(adap->cec_dir); 388 #ifdef CONFIG_CEC_NOTIFIER 389 cec_notifier_cec_adap_unregister(adap->notifier, adap); 390 #endif 391 cec_devnode_unregister(adap); 392 } 393 EXPORT_SYMBOL_GPL(cec_unregister_adapter); 394 395 void cec_delete_adapter(struct cec_adapter *adap) 396 { 397 if (IS_ERR_OR_NULL(adap)) 398 return; 399 if (adap->kthread_config) 400 kthread_stop(adap->kthread_config); 401 kthread_stop(adap->kthread); 402 if (adap->ops->adap_free) 403 adap->ops->adap_free(adap); 404 #ifdef CONFIG_MEDIA_CEC_RC 405 rc_free_device(adap->rc); 406 #endif 407 kfree(adap); 408 } 409 EXPORT_SYMBOL_GPL(cec_delete_adapter); 410 411 /* 412 * Initialise cec for linux 413 */ 414 static int __init cec_devnode_init(void) 415 { 416 int ret = alloc_chrdev_region(&cec_dev_t, 0, CEC_NUM_DEVICES, CEC_NAME); 417 418 if (ret < 0) { 419 pr_warn("cec: unable to allocate major\n"); 420 return ret; 421 } 422 423 #ifdef CONFIG_DEBUG_FS 424 top_cec_dir = debugfs_create_dir("cec", NULL); 425 if (IS_ERR_OR_NULL(top_cec_dir)) { 426 pr_warn("cec: Failed to create debugfs cec dir\n"); 427 top_cec_dir = NULL; 428 } 429 #endif 430 431 ret = bus_register(&cec_bus_type); 432 if (ret < 0) { 433 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES); 434 pr_warn("cec: bus_register failed\n"); 435 return -EIO; 436 } 437 438 return 0; 439 } 440 441 static void __exit cec_devnode_exit(void) 442 { 443 debugfs_remove_recursive(top_cec_dir); 444 bus_unregister(&cec_bus_type); 445 unregister_chrdev_region(cec_dev_t, CEC_NUM_DEVICES); 446 } 447 448 subsys_initcall(cec_devnode_init); 449 module_exit(cec_devnode_exit) 450 451 MODULE_AUTHOR("Hans Verkuil <hans.verkuil@cisco.com>"); 452 MODULE_DESCRIPTION("Device node registration for cec drivers"); 453 MODULE_LICENSE("GPL"); 454