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Andres Salomon392a3252012-07-10 19:31:51 -07001/*
2 * Generic driver for the OLPC Embedded Controller.
3 *
4 * Copyright (C) 2011-2012 One Laptop per Child Foundation.
5 *
6 * Licensed under the GPL v2 or later.
7 */
Andres Salomon3d26c202012-07-11 17:40:25 -07008#include <linux/completion.h>
Andres Salomon6cca83d2012-07-12 20:45:14 -07009#include <linux/debugfs.h>
Andres Salomon3d26c202012-07-11 17:40:25 -070010#include <linux/spinlock.h>
11#include <linux/mutex.h>
Andres Salomonac250412012-07-13 05:57:17 -070012#include <linux/platform_device.h>
Andres Salomond278b7a2012-07-13 15:54:25 -070013#include <linux/slab.h>
Andres Salomon3d26c202012-07-11 17:40:25 -070014#include <linux/workqueue.h>
Andres Salomon392a3252012-07-10 19:31:51 -070015#include <linux/module.h>
Andres Salomon3d26c202012-07-11 17:40:25 -070016#include <linux/list.h>
17#include <linux/olpc-ec.h>
Andres Salomon392a3252012-07-10 19:31:51 -070018#include <asm/olpc.h>
19
Andres Salomon3d26c202012-07-11 17:40:25 -070020struct ec_cmd_desc {
21 u8 cmd;
22 u8 *inbuf, *outbuf;
23 size_t inlen, outlen;
24
25 int err;
26 struct completion finished;
27 struct list_head node;
28
29 void *priv;
30};
31
Andres Salomond278b7a2012-07-13 15:54:25 -070032struct olpc_ec_priv {
33 struct olpc_ec_driver *drv;
Andres Salomon99ecb012012-07-13 17:10:45 -070034 struct work_struct worker;
35 struct mutex cmd_lock;
36
37 /* Pending EC commands */
38 struct list_head cmd_q;
39 spinlock_t cmd_q_lock;
Andres Salomond278b7a2012-07-13 15:54:25 -070040
Andres Salomon6cca83d2012-07-12 20:45:14 -070041 struct dentry *dbgfs_dir;
42
Andres Salomond278b7a2012-07-13 15:54:25 -070043 /*
44 * Running an EC command while suspending means we don't always finish
45 * the command before the machine suspends. This means that the EC
46 * is expecting the command protocol to finish, but we after a period
47 * of time (while the OS is asleep) the EC times out and restarts its
48 * idle loop. Meanwhile, the OS wakes up, thinks it's still in the
49 * middle of the command protocol, starts throwing random things at
50 * the EC... and everyone's uphappy.
51 */
52 bool suspended;
53};
54
Andres Salomon3d26c202012-07-11 17:40:25 -070055static struct olpc_ec_driver *ec_driver;
Andres Salomond278b7a2012-07-13 15:54:25 -070056static struct olpc_ec_priv *ec_priv;
Andres Salomon3d26c202012-07-11 17:40:25 -070057static void *ec_cb_arg;
Andres Salomon3d26c202012-07-11 17:40:25 -070058
59void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg)
60{
61 ec_driver = drv;
62 ec_cb_arg = arg;
63}
64EXPORT_SYMBOL_GPL(olpc_ec_driver_register);
65
66static void olpc_ec_worker(struct work_struct *w)
67{
Andres Salomon99ecb012012-07-13 17:10:45 -070068 struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker);
Andres Salomon3d26c202012-07-11 17:40:25 -070069 struct ec_cmd_desc *desc = NULL;
70 unsigned long flags;
71
72 /* Grab the first pending command from the queue */
Andres Salomon99ecb012012-07-13 17:10:45 -070073 spin_lock_irqsave(&ec->cmd_q_lock, flags);
74 if (!list_empty(&ec->cmd_q)) {
75 desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node);
Andres Salomon3d26c202012-07-11 17:40:25 -070076 list_del(&desc->node);
77 }
Andres Salomon99ecb012012-07-13 17:10:45 -070078 spin_unlock_irqrestore(&ec->cmd_q_lock, flags);
Andres Salomon3d26c202012-07-11 17:40:25 -070079
80 /* Do we actually have anything to do? */
81 if (!desc)
82 return;
83
84 /* Protect the EC hw with a mutex; only run one cmd at a time */
Andres Salomon99ecb012012-07-13 17:10:45 -070085 mutex_lock(&ec->cmd_lock);
Andres Salomon3d26c202012-07-11 17:40:25 -070086 desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
87 desc->outbuf, desc->outlen, ec_cb_arg);
Andres Salomon99ecb012012-07-13 17:10:45 -070088 mutex_unlock(&ec->cmd_lock);
Andres Salomon3d26c202012-07-11 17:40:25 -070089
90 /* Finished, wake up olpc_ec_cmd() */
91 complete(&desc->finished);
92
93 /* Run the worker thread again in case there are more cmds pending */
Andres Salomon99ecb012012-07-13 17:10:45 -070094 schedule_work(&ec->worker);
Andres Salomon3d26c202012-07-11 17:40:25 -070095}
96
97/*
98 * Throw a cmd descripter onto the list. We now have SMP OLPC machines, so
99 * locking is pretty critical.
100 */
Andres Salomon99ecb012012-07-13 17:10:45 -0700101static void queue_ec_descriptor(struct ec_cmd_desc *desc,
102 struct olpc_ec_priv *ec)
Andres Salomon3d26c202012-07-11 17:40:25 -0700103{
104 unsigned long flags;
105
106 INIT_LIST_HEAD(&desc->node);
107
Andres Salomon99ecb012012-07-13 17:10:45 -0700108 spin_lock_irqsave(&ec->cmd_q_lock, flags);
109 list_add_tail(&desc->node, &ec->cmd_q);
110 spin_unlock_irqrestore(&ec->cmd_q_lock, flags);
Andres Salomon3d26c202012-07-11 17:40:25 -0700111
Andres Salomon99ecb012012-07-13 17:10:45 -0700112 schedule_work(&ec->worker);
Andres Salomon3d26c202012-07-11 17:40:25 -0700113}
114
Andres Salomon392a3252012-07-10 19:31:51 -0700115int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
116{
Andres Salomond278b7a2012-07-13 15:54:25 -0700117 struct olpc_ec_priv *ec = ec_priv;
Andres Salomon3d26c202012-07-11 17:40:25 -0700118 struct ec_cmd_desc desc;
119
Andres Salomon3d26c202012-07-11 17:40:25 -0700120 /* Ensure a driver and ec hook have been registered */
121 if (WARN_ON(!ec_driver || !ec_driver->ec_cmd))
122 return -ENODEV;
123
Andres Salomond278b7a2012-07-13 15:54:25 -0700124 if (!ec)
125 return -ENOMEM;
126
127 /* Suspending in the middle of a command hoses things really badly */
128 if (WARN_ON(ec->suspended))
129 return -EBUSY;
130
Andres Salomon3d26c202012-07-11 17:40:25 -0700131 might_sleep();
132
133 desc.cmd = cmd;
134 desc.inbuf = inbuf;
135 desc.outbuf = outbuf;
136 desc.inlen = inlen;
137 desc.outlen = outlen;
138 desc.err = 0;
139 init_completion(&desc.finished);
140
Andres Salomon99ecb012012-07-13 17:10:45 -0700141 queue_ec_descriptor(&desc, ec);
Andres Salomon3d26c202012-07-11 17:40:25 -0700142
143 /* Timeouts must be handled in the platform-specific EC hook */
144 wait_for_completion(&desc.finished);
145
146 /* The worker thread dequeues the cmd; no need to do anything here */
147 return desc.err;
Andres Salomon392a3252012-07-10 19:31:51 -0700148}
149EXPORT_SYMBOL_GPL(olpc_ec_cmd);
Andres Salomonac250412012-07-13 05:57:17 -0700150
Andres Salomon6cca83d2012-07-12 20:45:14 -0700151#ifdef CONFIG_DEBUG_FS
152
153/*
154 * debugfs support for "generic commands", to allow sending
155 * arbitrary EC commands from userspace.
156 */
157
158#define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */
159#define EC_MAX_CMD_REPLY (8)
160
161static DEFINE_MUTEX(ec_dbgfs_lock);
162static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY];
163static unsigned int ec_dbgfs_resp_bytes;
164
165static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf,
166 size_t size, loff_t *ppos)
167{
168 int i, m;
169 unsigned char ec_cmd[EC_MAX_CMD_ARGS];
170 unsigned int ec_cmd_int[EC_MAX_CMD_ARGS];
171 char cmdbuf[64];
172 int ec_cmd_bytes;
173
174 mutex_lock(&ec_dbgfs_lock);
175
176 size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size);
177
178 m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0],
179 &ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2],
180 &ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]);
181 if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) {
182 /* reset to prevent overflow on read */
183 ec_dbgfs_resp_bytes = 0;
184
185 pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n");
186 size = -EINVAL;
187 goto out;
188 }
189
190 /* convert scanf'd ints to char */
191 ec_cmd_bytes = m - 2;
192 for (i = 0; i <= ec_cmd_bytes; i++)
193 ec_cmd[i] = ec_cmd_int[i];
194
Andy Shevchenko7d3777d2014-12-29 14:26:50 +0200195 pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %5ph, want %d returns\n",
196 ec_cmd[0], ec_cmd_bytes, ec_cmd + 1,
197 ec_dbgfs_resp_bytes);
Andres Salomon6cca83d2012-07-12 20:45:14 -0700198
199 olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1],
200 ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes);
201
Andy Shevchenko7d3777d2014-12-29 14:26:50 +0200202 pr_debug("olpc-ec: response %8ph (%d bytes expected)\n",
203 ec_dbgfs_resp, ec_dbgfs_resp_bytes);
Andres Salomon6cca83d2012-07-12 20:45:14 -0700204
205out:
206 mutex_unlock(&ec_dbgfs_lock);
207 return size;
208}
209
210static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf,
211 size_t size, loff_t *ppos)
212{
213 unsigned int i, r;
214 char *rp;
215 char respbuf[64];
216
217 mutex_lock(&ec_dbgfs_lock);
218 rp = respbuf;
219 rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
220 for (i = 1; i < ec_dbgfs_resp_bytes; i++)
221 rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
222 mutex_unlock(&ec_dbgfs_lock);
223 rp += sprintf(rp, "\n");
224
225 r = rp - respbuf;
226 return simple_read_from_buffer(buf, size, ppos, respbuf, r);
227}
228
229static const struct file_operations ec_dbgfs_ops = {
230 .write = ec_dbgfs_cmd_write,
231 .read = ec_dbgfs_cmd_read,
232};
233
234static struct dentry *olpc_ec_setup_debugfs(void)
235{
236 struct dentry *dbgfs_dir;
237
238 dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
239 if (IS_ERR_OR_NULL(dbgfs_dir))
240 return NULL;
241
242 debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);
243
244 return dbgfs_dir;
245}
246
247#else
248
249static struct dentry *olpc_ec_setup_debugfs(void)
250{
251 return NULL;
252}
253
254#endif /* CONFIG_DEBUG_FS */
255
Andres Salomonac250412012-07-13 05:57:17 -0700256static int olpc_ec_probe(struct platform_device *pdev)
257{
Andres Salomond278b7a2012-07-13 15:54:25 -0700258 struct olpc_ec_priv *ec;
Andres Salomonac250412012-07-13 05:57:17 -0700259 int err;
260
261 if (!ec_driver)
262 return -ENODEV;
263
Andres Salomond278b7a2012-07-13 15:54:25 -0700264 ec = kzalloc(sizeof(*ec), GFP_KERNEL);
265 if (!ec)
266 return -ENOMEM;
Andres Salomon99ecb012012-07-13 17:10:45 -0700267
Andres Salomond278b7a2012-07-13 15:54:25 -0700268 ec->drv = ec_driver;
Andres Salomon99ecb012012-07-13 17:10:45 -0700269 INIT_WORK(&ec->worker, olpc_ec_worker);
270 mutex_init(&ec->cmd_lock);
271
272 INIT_LIST_HEAD(&ec->cmd_q);
273 spin_lock_init(&ec->cmd_q_lock);
274
Andres Salomond278b7a2012-07-13 15:54:25 -0700275 ec_priv = ec;
276 platform_set_drvdata(pdev, ec);
277
Andres Salomonac250412012-07-13 05:57:17 -0700278 err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
Andres Salomon6cca83d2012-07-12 20:45:14 -0700279 if (err) {
280 ec_priv = NULL;
281 kfree(ec);
282 } else {
283 ec->dbgfs_dir = olpc_ec_setup_debugfs();
284 }
Andres Salomonac250412012-07-13 05:57:17 -0700285
286 return err;
287}
288
289static int olpc_ec_suspend(struct device *dev)
290{
291 struct platform_device *pdev = to_platform_device(dev);
Andres Salomond278b7a2012-07-13 15:54:25 -0700292 struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
293 int err = 0;
294
295 if (ec_driver->suspend)
296 err = ec_driver->suspend(pdev);
297 if (!err)
298 ec->suspended = true;
299
300 return err;
Andres Salomonac250412012-07-13 05:57:17 -0700301}
302
303static int olpc_ec_resume(struct device *dev)
304{
305 struct platform_device *pdev = to_platform_device(dev);
Andres Salomond278b7a2012-07-13 15:54:25 -0700306 struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
307
308 ec->suspended = false;
Andres Salomonac250412012-07-13 05:57:17 -0700309 return ec_driver->resume ? ec_driver->resume(pdev) : 0;
310}
311
312static const struct dev_pm_ops olpc_ec_pm_ops = {
313 .suspend_late = olpc_ec_suspend,
314 .resume_early = olpc_ec_resume,
315};
316
317static struct platform_driver olpc_ec_plat_driver = {
318 .probe = olpc_ec_probe,
319 .driver = {
320 .name = "olpc-ec",
321 .pm = &olpc_ec_pm_ops,
322 },
323};
324
325static int __init olpc_ec_init_module(void)
326{
327 return platform_driver_register(&olpc_ec_plat_driver);
328}
329
Daniel Drake93dbc1b2013-08-22 16:35:43 -0700330arch_initcall(olpc_ec_init_module);
Andres Salomonac250412012-07-13 05:57:17 -0700331
332MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
333MODULE_LICENSE("GPL");