Commit | Line | Data |
---|---|---|
392a325c AS |
1 | /* |
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 | */ | |
3d26c20b | 8 | #include <linux/completion.h> |
6cca83d4 | 9 | #include <linux/debugfs.h> |
3d26c20b AS |
10 | #include <linux/spinlock.h> |
11 | #include <linux/mutex.h> | |
ac250415 | 12 | #include <linux/platform_device.h> |
d278b7a2 | 13 | #include <linux/slab.h> |
3d26c20b | 14 | #include <linux/workqueue.h> |
392a325c | 15 | #include <linux/module.h> |
3d26c20b AS |
16 | #include <linux/list.h> |
17 | #include <linux/olpc-ec.h> | |
392a325c AS |
18 | #include <asm/olpc.h> |
19 | ||
3d26c20b AS |
20 | struct 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 | ||
d278b7a2 AS |
32 | struct olpc_ec_priv { |
33 | struct olpc_ec_driver *drv; | |
99ecb01c AS |
34 | 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; | |
d278b7a2 | 40 | |
6cca83d4 AS |
41 | struct dentry *dbgfs_dir; |
42 | ||
d278b7a2 AS |
43 | /* |
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 | ||
3d26c20b | 55 | static struct olpc_ec_driver *ec_driver; |
d278b7a2 | 56 | static struct olpc_ec_priv *ec_priv; |
3d26c20b | 57 | static void *ec_cb_arg; |
3d26c20b AS |
58 | |
59 | void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg) | |
60 | { | |
61 | ec_driver = drv; | |
62 | ec_cb_arg = arg; | |
63 | } | |
64 | EXPORT_SYMBOL_GPL(olpc_ec_driver_register); | |
65 | ||
66 | static void olpc_ec_worker(struct work_struct *w) | |
67 | { | |
99ecb01c | 68 | struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker); |
3d26c20b AS |
69 | struct ec_cmd_desc *desc = NULL; |
70 | unsigned long flags; | |
71 | ||
72 | /* Grab the first pending command from the queue */ | |
99ecb01c AS |
73 | 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); | |
3d26c20b AS |
76 | list_del(&desc->node); |
77 | } | |
99ecb01c | 78 | spin_unlock_irqrestore(&ec->cmd_q_lock, flags); |
3d26c20b AS |
79 | |
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 */ | |
99ecb01c | 85 | mutex_lock(&ec->cmd_lock); |
3d26c20b AS |
86 | desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen, |
87 | desc->outbuf, desc->outlen, ec_cb_arg); | |
99ecb01c | 88 | mutex_unlock(&ec->cmd_lock); |
3d26c20b AS |
89 | |
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 */ | |
99ecb01c | 94 | schedule_work(&ec->worker); |
3d26c20b AS |
95 | } |
96 | ||
97 | /* | |
98 | * Throw a cmd descripter onto the list. We now have SMP OLPC machines, so | |
99 | * locking is pretty critical. | |
100 | */ | |
99ecb01c AS |
101 | static void queue_ec_descriptor(struct ec_cmd_desc *desc, |
102 | struct olpc_ec_priv *ec) | |
3d26c20b AS |
103 | { |
104 | unsigned long flags; | |
105 | ||
106 | INIT_LIST_HEAD(&desc->node); | |
107 | ||
99ecb01c AS |
108 | 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); | |
3d26c20b | 111 | |
99ecb01c | 112 | schedule_work(&ec->worker); |
3d26c20b AS |
113 | } |
114 | ||
392a325c AS |
115 | int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen) |
116 | { | |
d278b7a2 | 117 | struct olpc_ec_priv *ec = ec_priv; |
3d26c20b AS |
118 | struct ec_cmd_desc desc; |
119 | ||
3d26c20b AS |
120 | /* Ensure a driver and ec hook have been registered */ |
121 | if (WARN_ON(!ec_driver || !ec_driver->ec_cmd)) | |
122 | return -ENODEV; | |
123 | ||
d278b7a2 AS |
124 | 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 | ||
3d26c20b AS |
131 | 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 | ||
99ecb01c | 141 | queue_ec_descriptor(&desc, ec); |
3d26c20b AS |
142 | |
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; | |
392a325c AS |
148 | } |
149 | EXPORT_SYMBOL_GPL(olpc_ec_cmd); | |
ac250415 | 150 | |
6cca83d4 AS |
151 | #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 | ||
161 | static DEFINE_MUTEX(ec_dbgfs_lock); | |
162 | static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY]; | |
163 | static unsigned int ec_dbgfs_resp_bytes; | |
164 | ||
165 | static 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 | ||
7d3777d1 AS |
195 | 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); | |
6cca83d4 AS |
198 | |
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 | ||
7d3777d1 AS |
202 | pr_debug("olpc-ec: response %8ph (%d bytes expected)\n", |
203 | ec_dbgfs_resp, ec_dbgfs_resp_bytes); | |
6cca83d4 AS |
204 | |
205 | out: | |
206 | mutex_unlock(&ec_dbgfs_lock); | |
207 | return size; | |
208 | } | |
209 | ||
210 | static 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 | ||
229 | static const struct file_operations ec_dbgfs_ops = { | |
230 | .write = ec_dbgfs_cmd_write, | |
231 | .read = ec_dbgfs_cmd_read, | |
232 | }; | |
233 | ||
234 | static 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 | ||
249 | static struct dentry *olpc_ec_setup_debugfs(void) | |
250 | { | |
251 | return NULL; | |
252 | } | |
253 | ||
254 | #endif /* CONFIG_DEBUG_FS */ | |
255 | ||
ac250415 AS |
256 | static int olpc_ec_probe(struct platform_device *pdev) |
257 | { | |
d278b7a2 | 258 | struct olpc_ec_priv *ec; |
ac250415 AS |
259 | int err; |
260 | ||
261 | if (!ec_driver) | |
262 | return -ENODEV; | |
263 | ||
d278b7a2 AS |
264 | ec = kzalloc(sizeof(*ec), GFP_KERNEL); |
265 | if (!ec) | |
266 | return -ENOMEM; | |
99ecb01c | 267 | |
d278b7a2 | 268 | ec->drv = ec_driver; |
99ecb01c AS |
269 | 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 | ||
d278b7a2 AS |
275 | ec_priv = ec; |
276 | platform_set_drvdata(pdev, ec); | |
277 | ||
ac250415 | 278 | err = ec_driver->probe ? ec_driver->probe(pdev) : 0; |
6cca83d4 AS |
279 | if (err) { |
280 | ec_priv = NULL; | |
281 | kfree(ec); | |
282 | } else { | |
283 | ec->dbgfs_dir = olpc_ec_setup_debugfs(); | |
284 | } | |
ac250415 AS |
285 | |
286 | return err; | |
287 | } | |
288 | ||
289 | static int olpc_ec_suspend(struct device *dev) | |
290 | { | |
291 | struct platform_device *pdev = to_platform_device(dev); | |
d278b7a2 AS |
292 | 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; | |
ac250415 AS |
301 | } |
302 | ||
303 | static int olpc_ec_resume(struct device *dev) | |
304 | { | |
305 | struct platform_device *pdev = to_platform_device(dev); | |
d278b7a2 AS |
306 | struct olpc_ec_priv *ec = platform_get_drvdata(pdev); |
307 | ||
308 | ec->suspended = false; | |
ac250415 AS |
309 | return ec_driver->resume ? ec_driver->resume(pdev) : 0; |
310 | } | |
311 | ||
312 | static const struct dev_pm_ops olpc_ec_pm_ops = { | |
313 | .suspend_late = olpc_ec_suspend, | |
314 | .resume_early = olpc_ec_resume, | |
315 | }; | |
316 | ||
317 | static 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 | ||
325 | static int __init olpc_ec_init_module(void) | |
326 | { | |
327 | return platform_driver_register(&olpc_ec_plat_driver); | |
328 | } | |
329 | ||
93dbc1b3 | 330 | arch_initcall(olpc_ec_init_module); |
ac250415 AS |
331 | |
332 | MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>"); | |
333 | MODULE_LICENSE("GPL"); |