Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/platform/olpc/olpc-ec.c

  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  */
  8 #include <linux/completion.h>
  9 #include <linux/debugfs.h>
 10 #include <linux/spinlock.h>
 11 #include <linux/mutex.h>
 12 #include <linux/platform_device.h>
 13 #include <linux/slab.h>
 14 #include <linux/workqueue.h>
 15 #include <linux/module.h>
 16 #include <linux/list.h>
 17 #include <linux/olpc-ec.h>
 18 #include <asm/olpc.h>
 19 
 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 
 32 struct olpc_ec_priv {
 33         struct olpc_ec_driver *drv;
 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;
 40 
 41         struct dentry *dbgfs_dir;
 42 
 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 
 55 static struct olpc_ec_driver *ec_driver;
 56 static struct olpc_ec_priv *ec_priv;
 57 static void *ec_cb_arg;
 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 {
 68         struct olpc_ec_priv *ec = container_of(w, struct olpc_ec_priv, worker);
 69         struct ec_cmd_desc *desc = NULL;
 70         unsigned long flags;
 71 
 72         /* Grab the first pending command from the queue */
 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);
 76                 list_del(&desc->node);
 77         }
 78         spin_unlock_irqrestore(&ec->cmd_q_lock, flags);
 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 */
 85         mutex_lock(&ec->cmd_lock);
 86         desc->err = ec_driver->ec_cmd(desc->cmd, desc->inbuf, desc->inlen,
 87                         desc->outbuf, desc->outlen, ec_cb_arg);
 88         mutex_unlock(&ec->cmd_lock);
 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 */
 94         schedule_work(&ec->worker);
 95 }
 96 
 97 /*
 98  * Throw a cmd descripter onto the list.  We now have SMP OLPC machines, so
 99  * locking is pretty critical.
100  */
101 static void queue_ec_descriptor(struct ec_cmd_desc *desc,
102                 struct olpc_ec_priv *ec)
103 {
104         unsigned long flags;
105 
106         INIT_LIST_HEAD(&desc->node);
107 
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);
111 
112         schedule_work(&ec->worker);
113 }
114 
115 int olpc_ec_cmd(u8 cmd, u8 *inbuf, size_t inlen, u8 *outbuf, size_t outlen)
116 {
117         struct olpc_ec_priv *ec = ec_priv;
118         struct ec_cmd_desc desc;
119 
120         /* Ensure a driver and ec hook have been registered */
121         if (WARN_ON(!ec_driver || !ec_driver->ec_cmd))
122                 return -ENODEV;
123 
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 
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 
141         queue_ec_descriptor(&desc, ec);
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;
148 }
149 EXPORT_SYMBOL_GPL(olpc_ec_cmd);
150 
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 
195         pr_debug("olpc-ec: debugfs cmd 0x%02x with %d args %02x %02x %02x %02x %02x, want %d returns\n",
196                         ec_cmd[0], ec_cmd_bytes, ec_cmd[1], ec_cmd[2],
197                         ec_cmd[3], ec_cmd[4], ec_cmd[5], ec_dbgfs_resp_bytes);
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 
202         pr_debug("olpc-ec: response %02x %02x %02x %02x %02x %02x %02x %02x (%d bytes expected)\n",
203                         ec_dbgfs_resp[0], ec_dbgfs_resp[1], ec_dbgfs_resp[2],
204                         ec_dbgfs_resp[3], ec_dbgfs_resp[4], ec_dbgfs_resp[5],
205                         ec_dbgfs_resp[6], ec_dbgfs_resp[7],
206                         ec_dbgfs_resp_bytes);
207 
208 out:
209         mutex_unlock(&ec_dbgfs_lock);
210         return size;
211 }
212 
213 static ssize_t ec_dbgfs_cmd_read(struct file *file, char __user *buf,
214                 size_t size, loff_t *ppos)
215 {
216         unsigned int i, r;
217         char *rp;
218         char respbuf[64];
219 
220         mutex_lock(&ec_dbgfs_lock);
221         rp = respbuf;
222         rp += sprintf(rp, "%02x", ec_dbgfs_resp[0]);
223         for (i = 1; i < ec_dbgfs_resp_bytes; i++)
224                 rp += sprintf(rp, ", %02x", ec_dbgfs_resp[i]);
225         mutex_unlock(&ec_dbgfs_lock);
226         rp += sprintf(rp, "\n");
227 
228         r = rp - respbuf;
229         return simple_read_from_buffer(buf, size, ppos, respbuf, r);
230 }
231 
232 static const struct file_operations ec_dbgfs_ops = {
233         .write = ec_dbgfs_cmd_write,
234         .read = ec_dbgfs_cmd_read,
235 };
236 
237 static struct dentry *olpc_ec_setup_debugfs(void)
238 {
239         struct dentry *dbgfs_dir;
240 
241         dbgfs_dir = debugfs_create_dir("olpc-ec", NULL);
242         if (IS_ERR_OR_NULL(dbgfs_dir))
243                 return NULL;
244 
245         debugfs_create_file("cmd", 0600, dbgfs_dir, NULL, &ec_dbgfs_ops);
246 
247         return dbgfs_dir;
248 }
249 
250 #else
251 
252 static struct dentry *olpc_ec_setup_debugfs(void)
253 {
254         return NULL;
255 }
256 
257 #endif /* CONFIG_DEBUG_FS */
258 
259 static int olpc_ec_probe(struct platform_device *pdev)
260 {
261         struct olpc_ec_priv *ec;
262         int err;
263 
264         if (!ec_driver)
265                 return -ENODEV;
266 
267         ec = kzalloc(sizeof(*ec), GFP_KERNEL);
268         if (!ec)
269                 return -ENOMEM;
270 
271         ec->drv = ec_driver;
272         INIT_WORK(&ec->worker, olpc_ec_worker);
273         mutex_init(&ec->cmd_lock);
274 
275         INIT_LIST_HEAD(&ec->cmd_q);
276         spin_lock_init(&ec->cmd_q_lock);
277 
278         ec_priv = ec;
279         platform_set_drvdata(pdev, ec);
280 
281         err = ec_driver->probe ? ec_driver->probe(pdev) : 0;
282         if (err) {
283                 ec_priv = NULL;
284                 kfree(ec);
285         } else {
286                 ec->dbgfs_dir = olpc_ec_setup_debugfs();
287         }
288 
289         return err;
290 }
291 
292 static int olpc_ec_suspend(struct device *dev)
293 {
294         struct platform_device *pdev = to_platform_device(dev);
295         struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
296         int err = 0;
297 
298         if (ec_driver->suspend)
299                 err = ec_driver->suspend(pdev);
300         if (!err)
301                 ec->suspended = true;
302 
303         return err;
304 }
305 
306 static int olpc_ec_resume(struct device *dev)
307 {
308         struct platform_device *pdev = to_platform_device(dev);
309         struct olpc_ec_priv *ec = platform_get_drvdata(pdev);
310 
311         ec->suspended = false;
312         return ec_driver->resume ? ec_driver->resume(pdev) : 0;
313 }
314 
315 static const struct dev_pm_ops olpc_ec_pm_ops = {
316         .suspend_late = olpc_ec_suspend,
317         .resume_early = olpc_ec_resume,
318 };
319 
320 static struct platform_driver olpc_ec_plat_driver = {
321         .probe = olpc_ec_probe,
322         .driver = {
323                 .name = "olpc-ec",
324                 .pm = &olpc_ec_pm_ops,
325         },
326 };
327 
328 static int __init olpc_ec_init_module(void)
329 {
330         return platform_driver_register(&olpc_ec_plat_driver);
331 }
332 
333 arch_initcall(olpc_ec_init_module);
334 
335 MODULE_AUTHOR("Andres Salomon <dilinger@queued.net>");
336 MODULE_LICENSE("GPL");
337 

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