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1// SPDX-License-Identifier: GPL-2.0-or-later2/*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 21struct 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 33struct 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 wakeup50 * sources).51 */52 u16 ec_wakeup_mask;53 54 /*55 * Running an EC command while suspending means we don't always finish56 * the command before the machine suspends. This means that the EC57 * is expecting the command protocol to finish, but we after a period58 * of time (while the OS is asleep) the EC times out and restarts its59 * idle loop. Meanwhile, the OS wakes up, thinks it's still in the60 * middle of the command protocol, starts throwing random things at61 * the EC... and everyone's uphappy.62 */63 bool suspended;64};65 66static struct olpc_ec_driver *ec_driver;67static struct olpc_ec_priv *ec_priv;68static void *ec_cb_arg;69 70void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg)71{72 ec_driver = drv;73 ec_cb_arg = arg;74}75EXPORT_SYMBOL_GPL(olpc_ec_driver_register);76 77static 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, so110 * locking is pretty critical.111 */112static 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 126int 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}163EXPORT_SYMBOL_GPL(olpc_ec_cmd);164 165void 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}174EXPORT_SYMBOL_GPL(olpc_ec_wakeup_set);175 176void 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}185EXPORT_SYMBOL_GPL(olpc_ec_wakeup_clear);186 187int 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}205EXPORT_SYMBOL_GPL(olpc_ec_mask_write);206 207/*208 * Returns true if the compile and runtime configurations allow for EC events209 * to wake the system.210 */211bool olpc_ec_wakeup_available(void)212{213 if (WARN_ON(!ec_driver))214 return false;215 216 return ec_driver->wakeup_available;217}218EXPORT_SYMBOL_GPL(olpc_ec_wakeup_available);219 220int 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}245EXPORT_SYMBOL_GPL(olpc_ec_sci_query);246 247#ifdef CONFIG_DEBUG_FS248 249/*250 * debugfs support for "generic commands", to allow sending251 * 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 257static DEFINE_MUTEX(ec_dbgfs_lock);258static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];259static unsigned int ec_dbgfs_resp_bytes;260 261static 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 301out:302 mutex_unlock(&ec_dbgfs_lock);303 return size;304}305 306static 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 325static const struct file_operations ec_dbgfs_ops = {326 .write = ec_dbgfs_cmd_write,327 .read = ec_dbgfs_cmd_read,328};329 330static struct dentry *olpc_ec_setup_debugfs(void)331{332 struct dentry *dbgfs_dir;333 334 dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);335 debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);336 337 return dbgfs_dir;338}339 340#else341 342static struct dentry *olpc_ec_setup_debugfs(void)343{344 return NULL;345}346 347#endif /* CONFIG_DEBUG_FS */348 349static int olpc_ec_set_dcon_power(struct olpc_ec_priv *ec, bool state)350{351 unsigned char ec_byte = state;352 int ret;353 354 if (ec->dcon_enabled == state)355 return 0;356 357 ret = olpc_ec_cmd(EC_DCON_POWER_MODE, &ec_byte, 1, NULL, 0);358 if (ret)359 return ret;360 361 ec->dcon_enabled = state;362 return 0;363}364 365static int dcon_regulator_enable(struct regulator_dev *rdev)366{367 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);368 369 return olpc_ec_set_dcon_power(ec, true);370}371 372static int dcon_regulator_disable(struct regulator_dev *rdev)373{374 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);375 376 return olpc_ec_set_dcon_power(ec, false);377}378 379static int dcon_regulator_is_enabled(struct regulator_dev *rdev)380{381 struct olpc_ec_priv *ec = rdev_get_drvdata(rdev);382 383 return ec->dcon_enabled ? 1 : 0;384}385 386static const struct regulator_ops dcon_regulator_ops = {387 .enable = dcon_regulator_enable,388 .disable = dcon_regulator_disable,389 .is_enabled = dcon_regulator_is_enabled,390};391 392static const struct regulator_desc dcon_desc = {393 .name = "dcon",394 .id = 0,395 .ops = &dcon_regulator_ops,396 .type = REGULATOR_VOLTAGE,397 .owner = THIS_MODULE,398 .enable_time = 25000,399};400 401static int olpc_ec_probe(struct platform_device *pdev)402{403 struct olpc_ec_priv *ec;404 struct regulator_config config = { };405 struct regulator_dev *regulator;406 int err;407 408 if (!ec_driver)409 return -ENODEV;410 411 ec = kzalloc(sizeof(*ec), GFP_KERNEL);412 if (!ec)413 return -ENOMEM;414 415 ec->drv = ec_driver;416 INIT_WORK(&ec->worker, olpc_ec_worker);417 mutex_init(&ec->cmd_lock);418 419 INIT_LIST_HEAD(&ec->cmd_q);420 spin_lock_init(&ec->cmd_q_lock);421 422 ec_priv = ec;423 platform_set_drvdata(pdev, ec);424 425 /* get the EC revision */426 err = olpc_ec_cmd(EC_FIRMWARE_REV, NULL, 0, &ec->version, 1);427 if (err)428 goto error;429 430 config.dev = pdev->dev.parent;431 config.driver_data = ec;432 ec->dcon_enabled = true;433 regulator = devm_regulator_register(&pdev->dev, &dcon_desc, &config);434 if (IS_ERR(regulator)) {435 dev_err(&pdev->dev, "failed to register DCON regulator\n");436 err = PTR_ERR(regulator);437 goto error;438 }439 440 ec->dbgfs_dir = olpc_ec_setup_debugfs();441 442 return 0;443 444error:445 ec_priv = NULL;446 kfree(ec);447 return err;448}449 450static int olpc_ec_suspend(struct device *dev)451{452 struct platform_device *pdev = to_platform_device(dev);453 struct olpc_ec_priv *ec = platform_get_drvdata(pdev);454 int err = 0;455 456 olpc_ec_mask_write(ec->ec_wakeup_mask);457 458 if (ec_driver->suspend)459 err = ec_driver->suspend(pdev);460 if (!err)461 ec->suspended = true;462 463 return err;464}465 466static int olpc_ec_resume(struct device *dev)467{468 struct platform_device *pdev = to_platform_device(dev);469 struct olpc_ec_priv *ec = platform_get_drvdata(pdev);470 471 ec->suspended = false;472 return ec_driver->resume ? ec_driver->resume(pdev) : 0;473}474 475static const struct dev_pm_ops olpc_ec_pm_ops = {476 .suspend_late = olpc_ec_suspend,477 .resume_early = olpc_ec_resume,478};479 480static struct platform_driver olpc_ec_plat_driver = {481 .probe = olpc_ec_probe,482 .driver = {483 .name = "olpc-ec",484 .pm = &olpc_ec_pm_ops,485 },486};487 488static int __init olpc_ec_init_module(void)489{490 return platform_driver_register(&olpc_ec_plat_driver);491}492arch_initcall(olpc_ec_init_module);493