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(head: &ec->cmd_q)) { |
86 | desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node); |
87 | list_del(entry: &desc->node); |
88 | } |
89 | spin_unlock_irqrestore(lock: &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(lock: &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(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(list: &desc->node); |
118 | |
119 | spin_lock_irqsave(&ec->cmd_q_lock, flags); |
120 | list_add_tail(new: &desc->node, head: &ec->cmd_q); |
121 | spin_unlock_irqrestore(lock: &ec->cmd_q_lock, flags); |
122 | |
123 | schedule_work(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(x: &desc.finished); |
154 | |
155 | queue_ec_descriptor(desc: &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(to: cmdbuf, available: sizeof(cmdbuf), ppos, from: buf, count: 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(lock: &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(buf: rp, fmt: "%02x" , ec_dbgfs_resp[0]); |
316 | for (i = 1; i < ec_dbgfs_resp_bytes; i++) |
317 | rp += sprintf(buf: rp, fmt: ", %02x" , ec_dbgfs_resp[i]); |
318 | mutex_unlock(lock: &ec_dbgfs_lock); |
319 | rp += sprintf(buf: rp, fmt: "\n" ); |
320 | |
321 | r = rp - respbuf; |
322 | return simple_read_from_buffer(to: buf, count: size, ppos, from: respbuf, available: 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(name: "olpc-ec" , NULL); |
335 | if (IS_ERR_OR_NULL(ptr: dbgfs_dir)) |
336 | return NULL; |
337 | |
338 | debugfs_create_file(name: "cmd" , mode: 0600, parent: dbgfs_dir, NULL, fops: &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, state: 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, state: 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(size: 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(list: &ec->cmd_q); |
423 | spin_lock_init(&ec->cmd_q_lock); |
424 | |
425 | ec_priv = ec; |
426 | platform_set_drvdata(pdev, data: 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(dev: &pdev->dev, regulator_desc: &dcon_desc, config: &config); |
437 | if (IS_ERR(ptr: regulator)) { |
438 | dev_err(&pdev->dev, "failed to register DCON regulator\n" ); |
439 | err = PTR_ERR(ptr: 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(objp: 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 | |