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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Generic driver for the OLPC Embedded Controller.
4 *
5 * Author: Andres Salomon <[email protected]>
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 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
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, so
110 * 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 events
209 * 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_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
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#else
341
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_obj(*ec);
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);