Commit | Line | Data |
---|---|---|
392a325c AS |
1 | /* |
2 | * Generic driver for the OLPC Embedded Controller. | |
3 | * | |
f48d1496 PG |
4 | * Author: Andres Salomon <dilinger@queued.net> |
5 | * | |
392a325c AS |
6 | * Copyright (C) 2011-2012 One Laptop per Child Foundation. |
7 | * | |
8 | * Licensed under the GPL v2 or later. | |
9 | */ | |
3d26c20b | 10 | #include <linux/completion.h> |
6cca83d4 | 11 | #include <linux/debugfs.h> |
3d26c20b AS |
12 | #include <linux/spinlock.h> |
13 | #include <linux/mutex.h> | |
ac250415 | 14 | #include <linux/platform_device.h> |
d278b7a2 | 15 | #include <linux/slab.h> |
3d26c20b | 16 | #include <linux/workqueue.h> |
f48d1496 | 17 | #include <linux/init.h> |
3d26c20b AS |
18 | #include <linux/list.h> |
19 | #include <linux/olpc-ec.h> | |
392a325c AS |
20 | #include <asm/olpc.h> |
21 | ||
3d26c20b AS |
22 | struct ec_cmd_desc { |
23 | u8 cmd; | |
24 | u8 *inbuf, *outbuf; | |
25 | size_t inlen, outlen; | |
26 | ||
27 | int err; | |
28 | struct completion finished; | |
29 | struct list_head node; | |
30 | ||
31 | void *priv; | |
32 | }; | |
33 | ||
d278b7a2 AS |
34 | struct olpc_ec_priv { |
35 | struct olpc_ec_driver *drv; | |
99ecb01c AS |
36 | struct work_struct worker; |
37 | struct mutex cmd_lock; | |
38 | ||
39 | /* Pending EC commands */ | |
40 | struct list_head cmd_q; | |
41 | spinlock_t cmd_q_lock; | |
d278b7a2 | 42 | |
6cca83d4 AS |
43 | struct dentry *dbgfs_dir; |
44 | ||
d278b7a2 AS |
45 | /* |
46 | * Running an EC command while suspending means we don't always finish | |
47 | * the command before the machine suspends. This means that the EC | |
48 | * is expecting the command protocol to finish, but we after a period | |
49 | * of time (while the OS is asleep) the EC times out and restarts its | |
50 | * idle loop. Meanwhile, the OS wakes up, thinks it's still in the | |
51 | * middle of the command protocol, starts throwing random things at | |
52 | * the EC... and everyone's uphappy. | |
53 | */ | |
54 | bool suspended; | |
55 | }; | |
56 | ||
3d26c20b | 57 | static struct olpc_ec_driver *ec_driver; |
d278b7a2 | 58 | static struct olpc_ec_priv *ec_priv; |
3d26c20b | 59 | static void *ec_cb_arg; |
3d26c20b AS |
60 | |
61 | void olpc_ec_driver_register(struct olpc_ec_driver *drv, void *arg) | |
62 | { | |
63 | ec_driver = drv; | |
64 | ec_cb_arg = arg; | |
65 | } | |
66 | EXPORT_SYMBOL_GPL(olpc_ec_driver_register); | |
67 | ||
68 | static void olpc_ec_worker(struct work_struct *w) | |
69 | { | |
99ecb01c | 70 | struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker); |
3d26c20b AS |
71 | struct ec_cmd_desc *desc = NULL; |
72 | unsigned long flags; | |
73 | ||
74 | /* Grab the first pending command from the queue */ | |
99ecb01c AS |
75 | spin_lock_irqsave(&ec->cmd_q_lock, flags); |
76 | if (!list_empty(&ec->cmd_q)) { | |
77 | desc = list_first_entry(&ec->cmd_q, struct ec_cmd_desc, node); | |
3d26c20b AS |
78 | list_del(&desc->node); |
79 | } | |
99ecb01c | 80 | spin_unlock_irqrestore(&ec->cmd_q_lock, flags); |
3d26c20b AS |
81 | |
82 | /* Do we actually have anything to do? */ | |
83 | if (!desc) | |
84 | return; | |
85 | ||
86 | /* Protect the EC hw with a mutex; only run one cmd at a time */ | |
99ecb01c | 87 | mutex_lock(&ec->cmd_lock); |
3d26c20b AS |
88 | desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen, |
89 | desc->outbuf, desc->outlen, ec_cb_arg); | |
99ecb01c | 90 | mutex_unlock(&ec->cmd_lock); |
3d26c20b AS |
91 | |
92 | /* Finished, wake up olpc_ec_cmd() */ | |
93 | complete(&desc->finished); | |
94 | ||
95 | /* Run the worker thread again in case there are more cmds pending */ | |
99ecb01c | 96 | schedule_work(&ec->worker); |
3d26c20b AS |
97 | } |
98 | ||
99 | /* | |
100 | * Throw a cmd descripter onto the list. We now have SMP OLPC machines, so | |
101 | * locking is pretty critical. | |
102 | */ | |
99ecb01c AS |
103 | static void queue_ec_descriptor(struct ec_cmd_desc *desc, |
104 | struct olpc_ec_priv *ec) | |
3d26c20b AS |
105 | { |
106 | unsigned long flags; | |
107 | ||
108 | INIT_LIST_HEAD(&desc->node); | |
109 | ||
99ecb01c AS |
110 | spin_lock_irqsave(&ec->cmd_q_lock, flags); |
111 | list_add_tail(&desc->node, &ec->cmd_q); | |
112 | spin_unlock_irqrestore(&ec->cmd_q_lock, flags); | |
3d26c20b | 113 | |
99ecb01c | 114 | schedule_work(&ec->worker); |
3d26c20b AS |
115 | } |
116 | ||
392a325c AS |
117 | int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen) |
118 | { | |
d278b7a2 | 119 | struct olpc_ec_priv *ec = ec_priv; |
3d26c20b AS |
120 | struct ec_cmd_desc desc; |
121 | ||
3d26c20b AS |
122 | /* Ensure a driver and ec hook have been registered */ |
123 | if (WARN_ON(!ec_driver || !ec_driver->ec_cmd)) | |
124 | return -ENODEV; | |
125 | ||
d278b7a2 AS |
126 | if (!ec) |
127 | return -ENOMEM; | |
128 | ||
129 | /* Suspending in the middle of a command hoses things really badly */ | |
130 | if (WARN_ON(ec->suspended)) | |
131 | return -EBUSY; | |
132 | ||
3d26c20b AS |
133 | might_sleep(); |
134 | ||
135 | desc.cmd = cmd; | |
136 | desc.inbuf = inbuf; | |
137 | desc.outbuf = outbuf; | |
138 | desc.inlen = inlen; | |
139 | desc.outlen = outlen; | |
140 | desc.err = 0; | |
141 | init_completion(&desc.finished); | |
142 | ||
99ecb01c | 143 | queue_ec_descriptor(&desc, ec); |
3d26c20b AS |
144 | |
145 | /* Timeouts must be handled in the platform-specific EC hook */ | |
146 | wait_for_completion(&desc.finished); | |
147 | ||
148 | /* The worker thread dequeues the cmd; no need to do anything here */ | |
149 | return desc.err; | |
392a325c AS |
150 | } |
151 | EXPORT_SYMBOL_GPL(olpc_ec_cmd); | |
ac250415 | 152 | |
6cca83d4 AS |
153 | #ifdef CONFIG_DEBUG_FS |
154 | ||
155 | /* | |
156 | * debugfs support for "generic commands", to allow sending | |
157 | * arbitrary EC commands from userspace. | |
158 | */ | |
159 | ||
160 | #define EC_MAX_CMD_ARGS (5 + 1) /* cmd byte + 5 args */ | |
161 | #define EC_MAX_CMD_REPLY (8) | |
162 | ||
163 | static DEFINE_MUTEX(ec_dbgfs_lock); | |
164 | static unsigned char ec_dbgfs_resp[EC_MAX_CMD_REPLY]; | |
165 | static unsigned int ec_dbgfs_resp_bytes; | |
166 | ||
167 | static ssize_t ec_dbgfs_cmd_write(struct file *file, const char __user *buf, | |
168 | size_t size, loff_t *ppos) | |
169 | { | |
170 | int i, m; | |
171 | unsigned char ec_cmd[EC_MAX_CMD_ARGS]; | |
172 | unsigned int ec_cmd_int[EC_MAX_CMD_ARGS]; | |
173 | char cmdbuf[64]; | |
174 | int ec_cmd_bytes; | |
175 | ||
176 | mutex_lock(&ec_dbgfs_lock); | |
177 | ||
178 | size = simple_write_to_buffer(cmdbuf, sizeof(cmdbuf), ppos, buf, size); | |
179 | ||
180 | m = sscanf(cmdbuf, "%x:%u %x %x %x %x %x", &ec_cmd_int[0], | |
181 | &ec_dbgfs_resp_bytes, &ec_cmd_int[1], &ec_cmd_int[2], | |
182 | &ec_cmd_int[3], &ec_cmd_int[4], &ec_cmd_int[5]); | |
183 | if (m < 2 || ec_dbgfs_resp_bytes > EC_MAX_CMD_REPLY) { | |
184 | /* reset to prevent overflow on read */ | |
185 | ec_dbgfs_resp_bytes = 0; | |
186 | ||
187 | pr_debug("olpc-ec: bad ec cmd: cmd:response-count [arg1 [arg2 ...]]\n"); | |
188 | size = -EINVAL; | |
189 | goto out; | |
190 | } | |
191 | ||
192 | /* convert scanf'd ints to char */ | |
193 | ec_cmd_bytes = m - 2; | |
194 | for (i = 0; i <= ec_cmd_bytes; i++) | |
195 | ec_cmd[i] = ec_cmd_int[i]; | |
196 | ||
7d3777d1 AS |
197 | pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %5ph, want %d returns\n", |
198 | ec_cmd[0], ec_cmd_bytes, ec_cmd + 1, | |
199 | ec_dbgfs_resp_bytes); | |
6cca83d4 AS |
200 | |
201 | olpc_ec_cmd(ec_cmd[0], (ec_cmd_bytes == 0) ? NULL : &ec_cmd[1], | |
202 | ec_cmd_bytes, ec_dbgfs_resp, ec_dbgfs_resp_bytes); | |
203 | ||
7d3777d1 AS |
204 | pr_debug("olpc-ec: response %8ph (%d bytes expected)\n", |
205 | ec_dbgfs_resp, ec_dbgfs_resp_bytes); | |
6cca83d4 AS |
206 | |
207 | out: | |
208 | mutex_unlock(&ec_dbgfs_lock); | |
209 | return size; | |
210 | } | |
211 | ||
212 | static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf, | |
213 | size_t size, loff_t *ppos) | |
214 | { | |
215 | unsigned int i, r; | |
216 | char *rp; | |
217 | char respbuf[64]; | |
218 | ||
219 | mutex_lock(&ec_dbgfs_lock); | |
220 | rp = respbuf; | |
221 | rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]); | |
222 | for (i = 1; i < ec_dbgfs_resp_bytes; i++) | |
223 | rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]); | |
224 | mutex_unlock(&ec_dbgfs_lock); | |
225 | rp += sprintf(rp, "\n"); | |
226 | ||
227 | r = rp - respbuf; | |
228 | return simple_read_from_buffer(buf, size, ppos, respbuf, r); | |
229 | } | |
230 | ||
231 | static const struct file_operations ec_dbgfs_ops = { | |
232 | .write = ec_dbgfs_cmd_write, | |
233 | .read = ec_dbgfs_cmd_read, | |
234 | }; | |
235 | ||
236 | static struct dentry *olpc_ec_setup_debugfs(void) | |
237 | { | |
238 | struct dentry *dbgfs_dir; | |
239 | ||
240 | dbgfs_dir = debugfs_create_dir("olpc-ec", NULL); | |
241 | if (IS_ERR_OR_NULL(dbgfs_dir)) | |
242 | return NULL; | |
243 | ||
244 | debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops); | |
245 | ||
246 | return dbgfs_dir; | |
247 | } | |
248 | ||
249 | #else | |
250 | ||
251 | static struct dentry *olpc_ec_setup_debugfs(void) | |
252 | { | |
253 | return NULL; | |
254 | } | |
255 | ||
256 | #endif /* CONFIG_DEBUG_FS */ | |
257 | ||
ac250415 AS |
258 | static int olpc_ec_probe(struct platform_device *pdev) |
259 | { | |
d278b7a2 | 260 | struct olpc_ec_priv *ec; |
ac250415 AS |
261 | int err; |
262 | ||
263 | if (!ec_driver) | |
264 | return -ENODEV; | |
265 | ||
d278b7a2 AS |
266 | ec = kzalloc(sizeof(*ec), GFP_KERNEL); |
267 | if (!ec) | |
268 | return -ENOMEM; | |
99ecb01c | 269 | |
d278b7a2 | 270 | ec->drv = ec_driver; |
99ecb01c AS |
271 | INIT_WORK(&ec->worker, olpc_ec_worker); |
272 | mutex_init(&ec->cmd_lock); | |
273 | ||
274 | INIT_LIST_HEAD(&ec->cmd_q); | |
275 | spin_lock_init(&ec->cmd_q_lock); | |
276 | ||
d278b7a2 AS |
277 | ec_priv = ec; |
278 | platform_set_drvdata(pdev, ec); | |
279 | ||
ac250415 | 280 | err = ec_driver->probe ? ec_driver->probe(pdev) : 0; |
6cca83d4 AS |
281 | if (err) { |
282 | ec_priv = NULL; | |
283 | kfree(ec); | |
284 | } else { | |
285 | ec->dbgfs_dir = olpc_ec_setup_debugfs(); | |
286 | } | |
ac250415 AS |
287 | |
288 | return err; | |
289 | } | |
290 | ||
291 | static int olpc_ec_suspend(struct device *dev) | |
292 | { | |
293 | struct platform_device *pdev = to_platform_device(dev); | |
d278b7a2 AS |
294 | struct olpc_ec_priv *ec = platform_get_drvdata(pdev); |
295 | int err = 0; | |
296 | ||
297 | if (ec_driver->suspend) | |
298 | err = ec_driver->suspend(pdev); | |
299 | if (!err) | |
300 | ec->suspended = true; | |
301 | ||
302 | return err; | |
ac250415 AS |
303 | } |
304 | ||
305 | static int olpc_ec_resume(struct device *dev) | |
306 | { | |
307 | struct platform_device *pdev = to_platform_device(dev); | |
d278b7a2 AS |
308 | struct olpc_ec_priv *ec = platform_get_drvdata(pdev); |
309 | ||
310 | ec->suspended = false; | |
ac250415 AS |
311 | return ec_driver->resume ? ec_driver->resume(pdev) : 0; |
312 | } | |
313 | ||
314 | static const struct dev_pm_ops olpc_ec_pm_ops = { | |
315 | .suspend_late = olpc_ec_suspend, | |
316 | .resume_early = olpc_ec_resume, | |
317 | }; | |
318 | ||
319 | static struct platform_driver olpc_ec_plat_driver = { | |
320 | .probe = olpc_ec_probe, | |
321 | .driver = { | |
322 | .name = "olpc-ec", | |
323 | .pm = &olpc_ec_pm_ops, | |
324 | }, | |
325 | }; | |
326 | ||
327 | static int __init olpc_ec_init_module(void) | |
328 | { | |
329 | return platform_driver_register(&olpc_ec_plat_driver); | |
330 | } | |
93dbc1b3 | 331 | arch_initcall(olpc_ec_init_module); |