1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Generic driver for the OLPC Embedded Controller. 4 * 5 * Author: Andres Salomon <dilinger@queued.net> 6 * 7 * Copyright (C) 2011-2012 One Laptop per Child Foundation. 8 */ 9 #include <linux/completion.h> 10 #include <linux/debugfs.h> 11 #include <linux/spinlock.h> 12 #include <linux/mutex.h> 13 #include <linux/platform_device.h> 14 #include <linux/slab.h> 15 #include <linux/workqueue.h> 16 #include <linux/init.h> 17 #include <linux/list.h> 18 #include <linux/regulator/driver.h> 19 #include <linux/olpc-ec.h> 20 21 struct ec_cmd_desc { 22 u8 cmd; 23 u8 *inbuf, *outbuf; 24 size_t inlen, outlen; 25 26 int err; 27 struct completion finished; 28 struct list_head node; 29 30 void *priv; 31 }; 32 33 struct olpc_ec_priv { 34 struct olpc_ec_driver *drv; 35 u8 version; 36 struct work_struct worker; 37 struct mutex cmd_lock; 38 39 /* DCON regulator */ 40 bool dcon_enabled; 41 42 /* Pending EC commands */ 43 struct list_head cmd_q; 44 spinlock_t cmd_q_lock; 45 46 struct dentry *dbgfs_dir; 47 48 /* 49 * EC event mask to be applied during suspend (defining wakeup 50 * sources). 51 */ 52 u16 ec_wakeup_mask; 53 54 /* 55 * Running an EC command while suspending means we don't always finish 56 * the command before the machine suspends. This means that the EC 57 * is expecting the command protocol to finish, but we after a period 58 * of time (while the OS is asleep) the EC times out and restarts its 59 * idle loop. Meanwhile, the OS wakes up, thinks it's still in the 60 * middle of the command protocol, starts throwing random things at 61 * the EC... and everyone's uphappy. 62 */ 63 bool suspended; 64 }; 65 66 static struct olpc_ec_driver *ec_driver; 67 static struct olpc_ec_priv *ec_priv; 68 static void *ec_cb_arg; 69 70 void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg) 71 { 72 ec_driver = drv; 73 ec_cb_arg = arg; 74 } 75 EXPORT_SYMBOL_GPL(olpc_ec_driver_register); 76 77 static void olpc_ec_worker(struct work_struct *w) 78 { 79 struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker); 80 struct ec_cmd_desc *desc = NULL; 81 unsigned long flags; 82 83 /* Grab the first pending command from the queue */ 84 spin_lock_irqsave(&ec->cmd_q_lock, flags); 85 if (!list_empty(&ec->cmd_q)) { 86 desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node); 87 list_del(&desc->node); 88 } 89 spin_unlock_irqrestore(&ec->cmd_q_lock, flags); 90 91 /* Do we actually have anything to do? */ 92 if (!desc) 93 return; 94 95 /* Protect the EC hw with a mutex; only run one cmd at a time */ 96 mutex_lock(&ec->cmd_lock); 97 desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen, 98 desc->outbuf, desc->outlen, ec_cb_arg); 99 mutex_unlock(&ec->cmd_lock); 100 101 /* Finished, wake up olpc_ec_cmd() */ 102 complete(&desc->finished); 103 104 /* Run the worker thread again in case there are more cmds pending */ 105 schedule_work(&ec->worker); 106 } 107 108 /* 109 * Throw a cmd descripter onto the list. We now have SMP OLPC machines, so 110 * locking is pretty critical. 111 */ 112 static void queue_ec_descriptor(struct ec_cmd_desc *desc, 113 struct olpc_ec_priv *ec) 114 { 115 unsigned long flags; 116 117 INIT_LIST_HEAD(&desc->node); 118 119 spin_lock_irqsave(&ec->cmd_q_lock, flags); 120 list_add_tail(&desc->node, &ec->cmd_q); 121 spin_unlock_irqrestore(&ec->cmd_q_lock, flags); 122 123 schedule_work(&ec->worker); 124 } 125 126 int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen) 127 { 128 struct olpc_ec_priv *ec = ec_priv; 129 struct ec_cmd_desc desc; 130 131 /* Driver not yet registered. */ 132 if (!ec_driver) 133 return -EPROBE_DEFER; 134 135 if (WARN_ON(!ec_driver->ec_cmd)) 136 return -ENODEV; 137 138 if (!ec) 139 return -ENOMEM; 140 141 /* Suspending in the middle of a command hoses things really badly */ 142 if (WARN_ON(ec->suspended)) 143 return -EBUSY; 144 145 might_sleep(); 146 147 desc.cmd = cmd; 148 desc.inbuf = inbuf; 149 desc.outbuf = outbuf; 150 desc.inlen = inlen; 151 desc.outlen = outlen; 152 desc.err = 0; 153 init_completion(&desc.finished); 154 155 queue_ec_descriptor(&desc, ec); 156 157 /* Timeouts must be handled in the platform-specific EC hook */ 158 wait_for_completion(&desc.finished); 159 160 /* The worker thread dequeues the cmd; no need to do anything here */ 161 return desc.err; 162 } 163 EXPORT_SYMBOL_GPL(olpc_ec_cmd); 164 165 void olpc_ec_wakeup_set(u16 value) 166 { 167 struct olpc_ec_priv *ec = ec_priv; 168 169 if (WARN_ON(!ec)) 170 return; 171 172 ec->ec_wakeup_mask |= value; 173 } 174 EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set); 175 176 void olpc_ec_wakeup_clear(u16 value) 177 { 178 struct olpc_ec_priv *ec = ec_priv; 179 180 if (WARN_ON(!ec)) 181 return; 182 183 ec->ec_wakeup_mask &= ~value; 184 } 185 EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear); 186 187 int olpc_ec_mask_write(u16 bits) 188 { 189 struct olpc_ec_priv *ec = ec_priv; 190 191 if (WARN_ON(!ec)) 192 return -ENODEV; 193 194 /* EC version 0x5f adds support for wide SCI mask */ 195 if (ec->version >= 0x5f) { 196 __be16 ec_word = cpu_to_be16(bits); 197 198 return olpc_ec_cmd(EC_WRITE_EXT_SCI_MASK, (void *)&ec_word, 2, NULL, 0); 199 } else { 200 u8 ec_byte = bits & 0xff; 201 202 return olpc_ec_cmd(EC_WRITE_SCI_MASK, &ec_byte, 1, NULL, 0); 203 } 204 } 205 EXPORT_SYMBOL_GPL(olpc_ec_mask_write); 206 207 /* 208 * Returns true if the compile and runtime configurations allow for EC events 209 * to wake the system. 210 */ 211 bool olpc_ec_wakeup_available(void) 212 { 213 if (WARN_ON(!ec_driver)) 214 return false; 215 216 return ec_driver->wakeup_available; 217 } 218 EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available); 219 220 int olpc_ec_sci_query(u16 *sci_value) 221 { 222 struct olpc_ec_priv *ec = ec_priv; 223 int ret; 224 225 if (WARN_ON(!ec)) 226 return -ENODEV; 227 228 /* EC version 0x5f adds support for wide SCI mask */ 229 if (ec->version >= 0x5f) { 230 __be16 ec_word; 231 232 ret = olpc_ec_cmd(EC_EXT_SCI_QUERY, NULL, 0, (void *)&ec_word, 2); 233 if (ret == 0) 234 *sci_value = be16_to_cpu(ec_word); 235 } else { 236 u8 ec_byte; 237 238 ret = olpc_ec_cmd(EC_SCI_QUERY, NULL, 0, &ec_byte, 1); 239 if (ret == 0) 240 *sci_value = ec_byte; 241 } 242 243 return ret; 244 } 245 EXPORT_SYMBOL_GPL(olpc_ec_sci_query); 246 247 #ifdef CONFIG_DEBUG_FS 248 249 /* 250 * debugfs support for "generic commands", to allow sending 251 * arbitrary EC commands from userspace. 252 */ 253 254 #define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */ 255 #define EC_MAX_CMD_REPLY (8) 256 257 static DEFINE_MUTEX(ec_dbgfs_lock); 258 static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY]; 259 static unsigned int ec_dbgfs_resp_bytes; 260 261 static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf, 262 size_t size, loff_t *ppos) 263 { 264 int i, m; 265 unsigned char ec_cmd[EC_MAX_CMD_ARGS]; 266 unsigned int ec_cmd_int[EC_MAX_CMD_ARGS]; 267 char cmdbuf[64] = ""; 268 int ec_cmd_bytes; 269 270 mutex_lock(&ec_dbgfs_lock); 271 272 size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size); 273 274 m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0], 275 &ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2], 276 &ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]); 277 if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) { 278 /* reset to prevent overflow on read */ 279 ec_dbgfs_resp_bytes = 0; 280 281 pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n"); 282 size = -EINVAL; 283 goto out; 284 } 285 286 /* convert scanf'd ints to char */ 287 ec_cmd_bytes = m - 2; 288 for (i = 0; i <= ec_cmd_bytes; i++) 289 ec_cmd[i] = ec_cmd_int[i]; 290 291 pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %5ph, want %d returns\n", 292 ec_cmd[0], ec_cmd_bytes, ec_cmd + 1, 293 ec_dbgfs_resp_bytes); 294 295 olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1], 296 ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes); 297 298 pr_debug("olpc-ec: response %8ph (%d bytes expected)\n", 299 ec_dbgfs_resp, ec_dbgfs_resp_bytes); 300 301 out: 302 mutex_unlock(&ec_dbgfs_lock); 303 return size; 304 } 305 306 static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf, 307 size_t size, loff_t *ppos) 308 { 309 unsigned int i, r; 310 char *rp; 311 char respbuf[64]; 312 313 mutex_lock(&ec_dbgfs_lock); 314 rp = respbuf; 315 rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]); 316 for (i = 1; i < ec_dbgfs_resp_bytes; i++) 317 rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]); 318 mutex_unlock(&ec_dbgfs_lock); 319 rp += sprintf(rp, "\n"); 320 321 r = rp - respbuf; 322 return simple_read_from_buffer(buf, size, ppos, respbuf, r); 323 } 324 325 static const struct file_operations ec_dbgfs_ops = { 326 .write = ec_dbgfs_cmd_write, 327 .read = ec_dbgfs_cmd_read, 328 }; 329 330 static struct dentry *olpc_ec_setup_debugfs(void) 331 { 332 struct dentry *dbgfs_dir; 333 334 dbgfs_dir = debugfs_create_dir("olpc-ec", NULL); 335 if (IS_ERR_OR_NULL(dbgfs_dir)) 336 return NULL; 337 338 debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops); 339 340 return dbgfs_dir; 341 } 342 343 #else 344 345 static struct dentry *olpc_ec_setup_debugfs(void) 346 { 347 return NULL; 348 } 349 350 #endif /* CONFIG_DEBUG_FS */ 351 352 static int olpc_ec_set_dcon_power(struct olpc_ec_priv *ec, bool state) 353 { 354 unsigned char ec_byte = state; 355 int ret; 356 357 if (ec->dcon_enabled == state) 358 return 0; 359 360 ret = olpc_ec_cmd(EC_DCON_POWER_MODE, &ec_byte, 1, NULL, 0); 361 if (ret) 362 return ret; 363 364 ec->dcon_enabled = state; 365 return 0; 366 } 367 368 static int dcon_regulator_enable(struct regulator_dev *rdev) 369 { 370 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); 371 372 return olpc_ec_set_dcon_power(ec, true); 373 } 374 375 static int dcon_regulator_disable(struct regulator_dev *rdev) 376 { 377 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); 378 379 return olpc_ec_set_dcon_power(ec, false); 380 } 381 382 static int dcon_regulator_is_enabled(struct regulator_dev *rdev) 383 { 384 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev); 385 386 return ec->dcon_enabled ? 1 : 0; 387 } 388 389 static const struct regulator_ops dcon_regulator_ops = { 390 .enable = dcon_regulator_enable, 391 .disable = dcon_regulator_disable, 392 .is_enabled = dcon_regulator_is_enabled, 393 }; 394 395 static const struct regulator_desc dcon_desc = { 396 .name = "dcon", 397 .id = 0, 398 .ops = &dcon_regulator_ops, 399 .type = REGULATOR_VOLTAGE, 400 .owner = THIS_MODULE, 401 .enable_time = 25000, 402 }; 403 404 static int olpc_ec_probe(struct platform_device *pdev) 405 { 406 struct olpc_ec_priv *ec; 407 struct regulator_config config = { }; 408 struct regulator_dev *regulator; 409 int err; 410 411 if (!ec_driver) 412 return -ENODEV; 413 414 ec = kzalloc(sizeof(*ec), GFP_KERNEL); 415 if (!ec) 416 return -ENOMEM; 417 418 ec->drv = ec_driver; 419 INIT_WORK(&ec->worker, olpc_ec_worker); 420 mutex_init(&ec->cmd_lock); 421 422 INIT_LIST_HEAD(&ec->cmd_q); 423 spin_lock_init(&ec->cmd_q_lock); 424 425 ec_priv = ec; 426 platform_set_drvdata(pdev, ec); 427 428 /* get the EC revision */ 429 err = olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0, &ec->version, 1); 430 if (err) 431 goto error; 432 433 config.dev = pdev->dev.parent; 434 config.driver_data = ec; 435 ec->dcon_enabled = true; 436 regulator = devm_regulator_register(&pdev->dev, &dcon_desc, &config); 437 if (IS_ERR(regulator)) { 438 dev_err(&pdev->dev, "failed to register DCON regulator\n"); 439 err = PTR_ERR(regulator); 440 goto error; 441 } 442 443 ec->dbgfs_dir = olpc_ec_setup_debugfs(); 444 445 return 0; 446 447 error: 448 ec_priv = NULL; 449 kfree(ec); 450 return err; 451 } 452 453 static int olpc_ec_suspend(struct device *dev) 454 { 455 struct platform_device *pdev = to_platform_device(dev); 456 struct olpc_ec_priv *ec = platform_get_drvdata(pdev); 457 int err = 0; 458 459 olpc_ec_mask_write(ec->ec_wakeup_mask); 460 461 if (ec_driver->suspend) 462 err = ec_driver->suspend(pdev); 463 if (!err) 464 ec->suspended = true; 465 466 return err; 467 } 468 469 static int olpc_ec_resume(struct device *dev) 470 { 471 struct platform_device *pdev = to_platform_device(dev); 472 struct olpc_ec_priv *ec = platform_get_drvdata(pdev); 473 474 ec->suspended = false; 475 return ec_driver->resume ? ec_driver->resume(pdev) : 0; 476 } 477 478 static const struct dev_pm_ops olpc_ec_pm_ops = { 479 .suspend_late = olpc_ec_suspend, 480 .resume_early = olpc_ec_resume, 481 }; 482 483 static struct platform_driver olpc_ec_plat_driver = { 484 .probe = olpc_ec_probe, 485 .driver = { 486 .name = "olpc-ec", 487 .pm = &olpc_ec_pm_ops, 488 }, 489 }; 490 491 static int __init olpc_ec_init_module(void) 492 { 493 return platform_driver_register(&olpc_ec_plat_driver); 494 } 495 arch_initcall(olpc_ec_init_module); 496