Linux kernel & device driver programming

Cross-Referenced Linux and Device Driver Code

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Version: [ 2.6.11.8 ] [ 2.6.25 ] [ 2.6.25.8 ] [ 2.6.31.13 ] Architecture: [ i386 ]
  1 /*
  2  * Input layer to RF Kill interface connector
  3  *
  4  * Copyright (c) 2007 Dmitry Torokhov
  5  * Copyright 2009 Johannes Berg <johannes@sipsolutions.net>
  6  *
  7  * This program is free software; you can redistribute it and/or modify it
  8  * under the terms of the GNU General Public License version 2 as published
  9  * by the Free Software Foundation.
 10  *
 11  * If you ever run into a situation in which you have a SW_ type rfkill
 12  * input device, then you can revive code that was removed in the patch
 13  * "rfkill-input: remove unused code".
 14  */
 15 
 16 #include <linux/input.h>
 17 #include <linux/slab.h>
 18 #include <linux/workqueue.h>
 19 #include <linux/init.h>
 20 #include <linux/rfkill.h>
 21 #include <linux/sched.h>
 22 
 23 #include "rfkill.h"
 24 
 25 enum rfkill_input_master_mode {
 26         RFKILL_INPUT_MASTER_UNLOCK = 0,
 27         RFKILL_INPUT_MASTER_RESTORE = 1,
 28         RFKILL_INPUT_MASTER_UNBLOCKALL = 2,
 29         NUM_RFKILL_INPUT_MASTER_MODES
 30 };
 31 
 32 /* Delay (in ms) between consecutive switch ops */
 33 #define RFKILL_OPS_DELAY 200
 34 
 35 static enum rfkill_input_master_mode rfkill_master_switch_mode =
 36                                         RFKILL_INPUT_MASTER_UNBLOCKALL;
 37 module_param_named(master_switch_mode, rfkill_master_switch_mode, uint, 0);
 38 MODULE_PARM_DESC(master_switch_mode,
 39         "SW_RFKILL_ALL ON should: 0=do nothing (only unlock); 1=restore; 2=unblock all");
 40 
 41 static spinlock_t rfkill_op_lock;
 42 static bool rfkill_op_pending;
 43 static unsigned long rfkill_sw_pending[BITS_TO_LONGS(NUM_RFKILL_TYPES)];
 44 static unsigned long rfkill_sw_state[BITS_TO_LONGS(NUM_RFKILL_TYPES)];
 45 
 46 enum rfkill_sched_op {
 47         RFKILL_GLOBAL_OP_EPO = 0,
 48         RFKILL_GLOBAL_OP_RESTORE,
 49         RFKILL_GLOBAL_OP_UNLOCK,
 50         RFKILL_GLOBAL_OP_UNBLOCK,
 51 };
 52 
 53 static enum rfkill_sched_op rfkill_master_switch_op;
 54 static enum rfkill_sched_op rfkill_op;
 55 
 56 static void __rfkill_handle_global_op(enum rfkill_sched_op op)
 57 {
 58         unsigned int i;
 59 
 60         switch (op) {
 61         case RFKILL_GLOBAL_OP_EPO:
 62                 rfkill_epo();
 63                 break;
 64         case RFKILL_GLOBAL_OP_RESTORE:
 65                 rfkill_restore_states();
 66                 break;
 67         case RFKILL_GLOBAL_OP_UNLOCK:
 68                 rfkill_remove_epo_lock();
 69                 break;
 70         case RFKILL_GLOBAL_OP_UNBLOCK:
 71                 rfkill_remove_epo_lock();
 72                 for (i = 0; i < NUM_RFKILL_TYPES; i++)
 73                         rfkill_switch_all(i, false);
 74                 break;
 75         default:
 76                 /* memory corruption or bug, fail safely */
 77                 rfkill_epo();
 78                 WARN(1, "Unknown requested operation %d! "
 79                         "rfkill Emergency Power Off activated\n",
 80                         op);
 81         }
 82 }
 83 
 84 static void __rfkill_handle_normal_op(const enum rfkill_type type,
 85                                       const bool complement)
 86 {
 87         bool blocked;
 88 
 89         blocked = rfkill_get_global_sw_state(type);
 90         if (complement)
 91                 blocked = !blocked;
 92 
 93         rfkill_switch_all(type, blocked);
 94 }
 95 
 96 static void rfkill_op_handler(struct work_struct *work)
 97 {
 98         unsigned int i;
 99         bool c;
100 
101         spin_lock_irq(&rfkill_op_lock);
102         do {
103                 if (rfkill_op_pending) {
104                         enum rfkill_sched_op op = rfkill_op;
105                         rfkill_op_pending = false;
106                         memset(rfkill_sw_pending, 0,
107                                 sizeof(rfkill_sw_pending));
108                         spin_unlock_irq(&rfkill_op_lock);
109 
110                         __rfkill_handle_global_op(op);
111 
112                         spin_lock_irq(&rfkill_op_lock);
113 
114                         /*
115                          * handle global ops first -- during unlocked period
116                          * we might have gotten a new global op.
117                          */
118                         if (rfkill_op_pending)
119                                 continue;
120                 }
121 
122                 if (rfkill_is_epo_lock_active())
123                         continue;
124 
125                 for (i = 0; i < NUM_RFKILL_TYPES; i++) {
126                         if (__test_and_clear_bit(i, rfkill_sw_pending)) {
127                                 c = __test_and_clear_bit(i, rfkill_sw_state);
128                                 spin_unlock_irq(&rfkill_op_lock);
129 
130                                 __rfkill_handle_normal_op(i, c);
131 
132                                 spin_lock_irq(&rfkill_op_lock);
133                         }
134                 }
135         } while (rfkill_op_pending);
136         spin_unlock_irq(&rfkill_op_lock);
137 }
138 
139 static DECLARE_DELAYED_WORK(rfkill_op_work, rfkill_op_handler);
140 static unsigned long rfkill_last_scheduled;
141 
142 static unsigned long rfkill_ratelimit(const unsigned long last)
143 {
144         const unsigned long delay = msecs_to_jiffies(RFKILL_OPS_DELAY);
145         return (time_after(jiffies, last + delay)) ? 0 : delay;
146 }
147 
148 static void rfkill_schedule_ratelimited(void)
149 {
150         if (delayed_work_pending(&rfkill_op_work))
151                 return;
152         schedule_delayed_work(&rfkill_op_work,
153                               rfkill_ratelimit(rfkill_last_scheduled));
154         rfkill_last_scheduled = jiffies;
155 }
156 
157 static void rfkill_schedule_global_op(enum rfkill_sched_op op)
158 {
159         unsigned long flags;
160 
161         spin_lock_irqsave(&rfkill_op_lock, flags);
162         rfkill_op = op;
163         rfkill_op_pending = true;
164         if (op == RFKILL_GLOBAL_OP_EPO && !rfkill_is_epo_lock_active()) {
165                 /* bypass the limiter for EPO */
166                 cancel_delayed_work(&rfkill_op_work);
167                 schedule_delayed_work(&rfkill_op_work, 0);
168                 rfkill_last_scheduled = jiffies;
169         } else
170                 rfkill_schedule_ratelimited();
171         spin_unlock_irqrestore(&rfkill_op_lock, flags);
172 }
173 
174 static void rfkill_schedule_toggle(enum rfkill_type type)
175 {
176         unsigned long flags;
177 
178         if (rfkill_is_epo_lock_active())
179                 return;
180 
181         spin_lock_irqsave(&rfkill_op_lock, flags);
182         if (!rfkill_op_pending) {
183                 __set_bit(type, rfkill_sw_pending);
184                 __change_bit(type, rfkill_sw_state);
185                 rfkill_schedule_ratelimited();
186         }
187         spin_unlock_irqrestore(&rfkill_op_lock, flags);
188 }
189 
190 static void rfkill_schedule_evsw_rfkillall(int state)
191 {
192         if (state)
193                 rfkill_schedule_global_op(rfkill_master_switch_op);
194         else
195                 rfkill_schedule_global_op(RFKILL_GLOBAL_OP_EPO);
196 }
197 
198 static void rfkill_event(struct input_handle *handle, unsigned int type,
199                         unsigned int code, int data)
200 {
201         if (type == EV_KEY && data == 1) {
202                 switch (code) {
203                 case KEY_WLAN:
204                         rfkill_schedule_toggle(RFKILL_TYPE_WLAN);
205                         break;
206                 case KEY_BLUETOOTH:
207                         rfkill_schedule_toggle(RFKILL_TYPE_BLUETOOTH);
208                         break;
209                 case KEY_UWB:
210                         rfkill_schedule_toggle(RFKILL_TYPE_UWB);
211                         break;
212                 case KEY_WIMAX:
213                         rfkill_schedule_toggle(RFKILL_TYPE_WIMAX);
214                         break;
215                 }
216         } else if (type == EV_SW && code == SW_RFKILL_ALL)
217                 rfkill_schedule_evsw_rfkillall(data);
218 }
219 
220 static int rfkill_connect(struct input_handler *handler, struct input_dev *dev,
221                           const struct input_device_id *id)
222 {
223         struct input_handle *handle;
224         int error;
225 
226         handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL);
227         if (!handle)
228                 return -ENOMEM;
229 
230         handle->dev = dev;
231         handle->handler = handler;
232         handle->name = "rfkill";
233 
234         /* causes rfkill_start() to be called */
235         error = input_register_handle(handle);
236         if (error)
237                 goto err_free_handle;
238 
239         error = input_open_device(handle);
240         if (error)
241                 goto err_unregister_handle;
242 
243         return 0;
244 
245  err_unregister_handle:
246         input_unregister_handle(handle);
247  err_free_handle:
248         kfree(handle);
249         return error;
250 }
251 
252 static void rfkill_start(struct input_handle *handle)
253 {
254         /*
255          * Take event_lock to guard against configuration changes, we
256          * should be able to deal with concurrency with rfkill_event()
257          * just fine (which event_lock will also avoid).
258          */
259         spin_lock_irq(&handle->dev->event_lock);
260 
261         if (test_bit(EV_SW, handle->dev->evbit) &&
262             test_bit(SW_RFKILL_ALL, handle->dev->swbit))
263                 rfkill_schedule_evsw_rfkillall(test_bit(SW_RFKILL_ALL,
264                                                         handle->dev->sw));
265 
266         spin_unlock_irq(&handle->dev->event_lock);
267 }
268 
269 static void rfkill_disconnect(struct input_handle *handle)
270 {
271         input_close_device(handle);
272         input_unregister_handle(handle);
273         kfree(handle);
274 }
275 
276 static const struct input_device_id rfkill_ids[] = {
277         {
278                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
279                 .evbit = { BIT_MASK(EV_KEY) },
280                 .keybit = { [BIT_WORD(KEY_WLAN)] = BIT_MASK(KEY_WLAN) },
281         },
282         {
283                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
284                 .evbit = { BIT_MASK(EV_KEY) },
285                 .keybit = { [BIT_WORD(KEY_BLUETOOTH)] = BIT_MASK(KEY_BLUETOOTH) },
286         },
287         {
288                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
289                 .evbit = { BIT_MASK(EV_KEY) },
290                 .keybit = { [BIT_WORD(KEY_UWB)] = BIT_MASK(KEY_UWB) },
291         },
292         {
293                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_KEYBIT,
294                 .evbit = { BIT_MASK(EV_KEY) },
295                 .keybit = { [BIT_WORD(KEY_WIMAX)] = BIT_MASK(KEY_WIMAX) },
296         },
297         {
298                 .flags = INPUT_DEVICE_ID_MATCH_EVBIT | INPUT_DEVICE_ID_MATCH_SWBIT,
299                 .evbit = { BIT(EV_SW) },
300                 .swbit = { [BIT_WORD(SW_RFKILL_ALL)] = BIT_MASK(SW_RFKILL_ALL) },
301         },
302         { }
303 };
304 
305 static struct input_handler rfkill_handler = {
306         .name = "rfkill",
307         .event = rfkill_event,
308         .connect = rfkill_connect,
309         .start = rfkill_start,
310         .disconnect = rfkill_disconnect,
311         .id_table = rfkill_ids,
312 };
313 
314 int __init rfkill_handler_init(void)
315 {
316         switch (rfkill_master_switch_mode) {
317         case RFKILL_INPUT_MASTER_UNBLOCKALL:
318                 rfkill_master_switch_op = RFKILL_GLOBAL_OP_UNBLOCK;
319                 break;
320         case RFKILL_INPUT_MASTER_RESTORE:
321                 rfkill_master_switch_op = RFKILL_GLOBAL_OP_RESTORE;
322                 break;
323         case RFKILL_INPUT_MASTER_UNLOCK:
324                 rfkill_master_switch_op = RFKILL_GLOBAL_OP_UNLOCK;
325                 break;
326         default:
327                 return -EINVAL;
328         }
329 
330         spin_lock_init(&rfkill_op_lock);
331 
332         /* Avoid delay at first schedule */
333         rfkill_last_scheduled =
334                         jiffies - msecs_to_jiffies(RFKILL_OPS_DELAY) - 1;
335         return input_register_handler(&rfkill_handler);
336 }
337 
338 void __exit rfkill_handler_exit(void)
339 {
340         input_unregister_handler(&rfkill_handler);
341         cancel_delayed_work_sync(&rfkill_op_work);
342 }
343 
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