Free Electrons

Embedded Linux Experts

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
/*
 * Linux WiMAX
 * RF-kill framework integration
 *
 *
 * Copyright (C) 2008 Intel Corporation <linux-wimax@intel.com>
 * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 *
 *
 * This integrates into the Linux Kernel rfkill susbystem so that the
 * drivers just have to do the bare minimal work, which is providing a
 * method to set the software RF-Kill switch and to report changes in
 * the software and hardware switch status.
 *
 * A non-polled generic rfkill device is embedded into the WiMAX
 * subsystem's representation of a device.
 *
 * FIXME: Need polled support? Let drivers provide a poll routine
 *	  and hand it to rfkill ops then?
 *
 * All device drivers have to do is after wimax_dev_init(), call
 * wimax_report_rfkill_hw() and wimax_report_rfkill_sw() to update
 * initial state and then every time it changes. See wimax.h:struct
 * wimax_dev for more information.
 *
 * ROADMAP
 *
 * wimax_gnl_doit_rfkill()      User space calling wimax_rfkill()
 *   wimax_rfkill()             Kernel calling wimax_rfkill()
 *     __wimax_rf_toggle_radio()
 *
 * wimax_rfkill_set_radio_block()  RF-Kill subsystem calling
 *   __wimax_rf_toggle_radio()
 *
 * __wimax_rf_toggle_radio()
 *   wimax_dev->op_rfkill_sw_toggle() Driver backend
 *   __wimax_state_change()
 *
 * wimax_report_rfkill_sw()     Driver reports state change
 *   __wimax_state_change()
 *
 * wimax_report_rfkill_hw()     Driver reports state change
 *   __wimax_state_change()
 *
 * wimax_rfkill_add()           Initialize/shutdown rfkill support
 * wimax_rfkill_rm()            [called by wimax_dev_add/rm()]
 */

#include <net/wimax.h>
#include <net/genetlink.h>
#include <linux/wimax.h>
#include <linux/security.h>
#include <linux/rfkill.h>
#include <linux/export.h>
#include "wimax-internal.h"

#define D_SUBMODULE op_rfkill
#include "debug-levels.h"

/**
 * wimax_report_rfkill_hw - Reports changes in the hardware RF switch
 *
 * @wimax_dev: WiMAX device descriptor
 *
 * @state: New state of the RF Kill switch. %WIMAX_RF_ON radio on,
 *     %WIMAX_RF_OFF radio off.
 *
 * When the device detects a change in the state of thehardware RF
 * switch, it must call this function to let the WiMAX kernel stack
 * know that the state has changed so it can be properly propagated.
 *
 * The WiMAX stack caches the state (the driver doesn't need to). As
 * well, as the change is propagated it will come back as a request to
 * change the software state to mirror the hardware state.
 *
 * If the device doesn't have a hardware kill switch, just report
 * it on initialization as always on (%WIMAX_RF_ON, radio on).
 */
void wimax_report_rfkill_hw(struct wimax_dev *wimax_dev,
			    enum wimax_rf_state state)
{
	int result;
	struct device *dev = wimax_dev_to_dev(wimax_dev);
	enum wimax_st wimax_state;

	d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
	BUG_ON(state == WIMAX_RF_QUERY);
	BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);

	mutex_lock(&wimax_dev->mutex);
	result = wimax_dev_is_ready(wimax_dev);
	if (result < 0)
		goto error_not_ready;

	if (state != wimax_dev->rf_hw) {
		wimax_dev->rf_hw = state;
		if (wimax_dev->rf_hw == WIMAX_RF_ON &&
		    wimax_dev->rf_sw == WIMAX_RF_ON)
			wimax_state = WIMAX_ST_READY;
		else
			wimax_state = WIMAX_ST_RADIO_OFF;

		result = rfkill_set_hw_state(wimax_dev->rfkill,
					     state == WIMAX_RF_OFF);

		__wimax_state_change(wimax_dev, wimax_state);
	}
error_not_ready:
	mutex_unlock(&wimax_dev->mutex);
	d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
		wimax_dev, state, result);
}
EXPORT_SYMBOL_GPL(wimax_report_rfkill_hw);


/**
 * wimax_report_rfkill_sw - Reports changes in the software RF switch
 *
 * @wimax_dev: WiMAX device descriptor
 *
 * @state: New state of the RF kill switch. %WIMAX_RF_ON radio on,
 *     %WIMAX_RF_OFF radio off.
 *
 * Reports changes in the software RF switch state to the the WiMAX
 * stack.
 *
 * The main use is during initialization, so the driver can query the
 * device for its current software radio kill switch state and feed it
 * to the system.
 *
 * On the side, the device does not change the software state by
 * itself. In practice, this can happen, as the device might decide to
 * switch (in software) the radio off for different reasons.
 */
void wimax_report_rfkill_sw(struct wimax_dev *wimax_dev,
			    enum wimax_rf_state state)
{
	int result;
	struct device *dev = wimax_dev_to_dev(wimax_dev);
	enum wimax_st wimax_state;

	d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
	BUG_ON(state == WIMAX_RF_QUERY);
	BUG_ON(state != WIMAX_RF_ON && state != WIMAX_RF_OFF);

	mutex_lock(&wimax_dev->mutex);
	result = wimax_dev_is_ready(wimax_dev);
	if (result < 0)
		goto error_not_ready;

	if (state != wimax_dev->rf_sw) {
		wimax_dev->rf_sw = state;
		if (wimax_dev->rf_hw == WIMAX_RF_ON &&
		    wimax_dev->rf_sw == WIMAX_RF_ON)
			wimax_state = WIMAX_ST_READY;
		else
			wimax_state = WIMAX_ST_RADIO_OFF;
		__wimax_state_change(wimax_dev, wimax_state);
		rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
	}
error_not_ready:
	mutex_unlock(&wimax_dev->mutex);
	d_fnend(3, dev, "(wimax_dev %p state %u) = void [%d]\n",
		wimax_dev, state, result);
}
EXPORT_SYMBOL_GPL(wimax_report_rfkill_sw);


/*
 * Callback for the RF Kill toggle operation
 *
 * This function is called by:
 *
 * - The rfkill subsystem when the RF-Kill key is pressed in the
 *   hardware and the driver notifies through
 *   wimax_report_rfkill_hw(). The rfkill subsystem ends up calling back
 *   here so the software RF Kill switch state is changed to reflect
 *   the hardware switch state.
 *
 * - When the user sets the state through sysfs' rfkill/state file
 *
 * - When the user calls wimax_rfkill().
 *
 * This call blocks!
 *
 * WARNING! When we call rfkill_unregister(), this will be called with
 * state 0!
 *
 * WARNING: wimax_dev must be locked
 */
static
int __wimax_rf_toggle_radio(struct wimax_dev *wimax_dev,
			    enum wimax_rf_state state)
{
	int result = 0;
	struct device *dev = wimax_dev_to_dev(wimax_dev);
	enum wimax_st wimax_state;

	might_sleep();
	d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
	if (wimax_dev->rf_sw == state)
		goto out_no_change;
	if (wimax_dev->op_rfkill_sw_toggle != NULL)
		result = wimax_dev->op_rfkill_sw_toggle(wimax_dev, state);
	else if (state == WIMAX_RF_OFF)	/* No op? can't turn off */
		result = -ENXIO;
	else				/* No op? can turn on */
		result = 0;		/* should never happen tho */
	if (result >= 0) {
		result = 0;
		wimax_dev->rf_sw = state;
		wimax_state = state == WIMAX_RF_ON ?
			WIMAX_ST_READY : WIMAX_ST_RADIO_OFF;
		__wimax_state_change(wimax_dev, wimax_state);
	}
out_no_change:
	d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
		wimax_dev, state, result);
	return result;
}


/*
 * Translate from rfkill state to wimax state
 *
 * NOTE: Special state handling rules here
 *
 *     Just pretend the call didn't happen if we are in a state where
 *     we know for sure it cannot be handled (WIMAX_ST_DOWN or
 *     __WIMAX_ST_QUIESCING). rfkill() needs it to register and
 *     unregister, as it will run this path.
 *
 * NOTE: This call will block until the operation is completed.
 */
static int wimax_rfkill_set_radio_block(void *data, bool blocked)
{
	int result;
	struct wimax_dev *wimax_dev = data;
	struct device *dev = wimax_dev_to_dev(wimax_dev);
	enum wimax_rf_state rf_state;

	d_fnstart(3, dev, "(wimax_dev %p blocked %u)\n", wimax_dev, blocked);
	rf_state = WIMAX_RF_ON;
	if (blocked)
		rf_state = WIMAX_RF_OFF;
	mutex_lock(&wimax_dev->mutex);
	if (wimax_dev->state <= __WIMAX_ST_QUIESCING)
		result = 0;
	else
		result = __wimax_rf_toggle_radio(wimax_dev, rf_state);
	mutex_unlock(&wimax_dev->mutex);
	d_fnend(3, dev, "(wimax_dev %p blocked %u) = %d\n",
		wimax_dev, blocked, result);
	return result;
}

static const struct rfkill_ops wimax_rfkill_ops = {
	.set_block = wimax_rfkill_set_radio_block,
};

/**
 * wimax_rfkill - Set the software RF switch state for a WiMAX device
 *
 * @wimax_dev: WiMAX device descriptor
 *
 * @state: New RF state.
 *
 * Returns:
 *
 * >= 0 toggle state if ok, < 0 errno code on error. The toggle state
 * is returned as a bitmap, bit 0 being the hardware RF state, bit 1
 * the software RF state.
 *
 * 0 means disabled (%WIMAX_RF_ON, radio on), 1 means enabled radio
 * off (%WIMAX_RF_OFF).
 *
 * Description:
 *
 * Called by the user when he wants to request the WiMAX radio to be
 * switched on (%WIMAX_RF_ON) or off (%WIMAX_RF_OFF). With
 * %WIMAX_RF_QUERY, just the current state is returned.
 *
 * NOTE:
 *
 * This call will block until the operation is complete.
 */
int wimax_rfkill(struct wimax_dev *wimax_dev, enum wimax_rf_state state)
{
	int result;
	struct device *dev = wimax_dev_to_dev(wimax_dev);

	d_fnstart(3, dev, "(wimax_dev %p state %u)\n", wimax_dev, state);
	mutex_lock(&wimax_dev->mutex);
	result = wimax_dev_is_ready(wimax_dev);
	if (result < 0) {
		/* While initializing, < 1.4.3 wimax-tools versions use
		 * this call to check if the device is a valid WiMAX
		 * device; so we allow it to proceed always,
		 * considering the radios are all off. */
		if (result == -ENOMEDIUM && state == WIMAX_RF_QUERY)
			result = WIMAX_RF_OFF << 1 | WIMAX_RF_OFF;
		goto error_not_ready;
	}
	switch (state) {
	case WIMAX_RF_ON:
	case WIMAX_RF_OFF:
		result = __wimax_rf_toggle_radio(wimax_dev, state);
		if (result < 0)
			goto error;
		rfkill_set_sw_state(wimax_dev->rfkill, state == WIMAX_RF_OFF);
		break;
	case WIMAX_RF_QUERY:
		break;
	default:
		result = -EINVAL;
		goto error;
	}
	result = wimax_dev->rf_sw << 1 | wimax_dev->rf_hw;
error:
error_not_ready:
	mutex_unlock(&wimax_dev->mutex);
	d_fnend(3, dev, "(wimax_dev %p state %u) = %d\n",
		wimax_dev, state, result);
	return result;
}
EXPORT_SYMBOL(wimax_rfkill);


/*
 * Register a new WiMAX device's RF Kill support
 *
 * WARNING: wimax_dev->mutex must be unlocked
 */
int wimax_rfkill_add(struct wimax_dev *wimax_dev)
{
	int result;
	struct rfkill *rfkill;
	struct device *dev = wimax_dev_to_dev(wimax_dev);

	d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
	/* Initialize RF Kill */
	result = -ENOMEM;
	rfkill = rfkill_alloc(wimax_dev->name, dev, RFKILL_TYPE_WIMAX,
			      &wimax_rfkill_ops, wimax_dev);
	if (rfkill == NULL)
		goto error_rfkill_allocate;

	d_printf(1, dev, "rfkill %p\n", rfkill);

	wimax_dev->rfkill = rfkill;

	rfkill_init_sw_state(rfkill, 1);
	result = rfkill_register(wimax_dev->rfkill);
	if (result < 0)
		goto error_rfkill_register;

	/* If there is no SW toggle op, SW RFKill is always on */
	if (wimax_dev->op_rfkill_sw_toggle == NULL)
		wimax_dev->rf_sw = WIMAX_RF_ON;

	d_fnend(3, dev, "(wimax_dev %p) = 0\n", wimax_dev);
	return 0;

error_rfkill_register:
	rfkill_destroy(wimax_dev->rfkill);
error_rfkill_allocate:
	d_fnend(3, dev, "(wimax_dev %p) = %d\n", wimax_dev, result);
	return result;
}


/*
 * Deregister a WiMAX device's RF Kill support
 *
 * Ick, we can't call rfkill_free() after rfkill_unregister()...oh
 * well.
 *
 * WARNING: wimax_dev->mutex must be unlocked
 */
void wimax_rfkill_rm(struct wimax_dev *wimax_dev)
{
	struct device *dev = wimax_dev_to_dev(wimax_dev);
	d_fnstart(3, dev, "(wimax_dev %p)\n", wimax_dev);
	rfkill_unregister(wimax_dev->rfkill);
	rfkill_destroy(wimax_dev->rfkill);
	d_fnend(3, dev, "(wimax_dev %p)\n", wimax_dev);
}


/*
 * Exporting to user space over generic netlink
 *
 * Parse the rfkill command from user space, return a combination
 * value that describe the states of the different toggles.
 *
 * Only one attribute: the new state requested (on, off or no change,
 * just query).
 */

int wimax_gnl_doit_rfkill(struct sk_buff *skb, struct genl_info *info)
{
	int result, ifindex;
	struct wimax_dev *wimax_dev;
	struct device *dev;
	enum wimax_rf_state new_state;

	d_fnstart(3, NULL, "(skb %p info %p)\n", skb, info);
	result = -ENODEV;
	if (info->attrs[WIMAX_GNL_RFKILL_IFIDX] == NULL) {
		printk(KERN_ERR "WIMAX_GNL_OP_RFKILL: can't find IFIDX "
			"attribute\n");
		goto error_no_wimax_dev;
	}
	ifindex = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_IFIDX]);
	wimax_dev = wimax_dev_get_by_genl_info(info, ifindex);
	if (wimax_dev == NULL)
		goto error_no_wimax_dev;
	dev = wimax_dev_to_dev(wimax_dev);
	result = -EINVAL;
	if (info->attrs[WIMAX_GNL_RFKILL_STATE] == NULL) {
		dev_err(dev, "WIMAX_GNL_RFKILL: can't find RFKILL_STATE "
			"attribute\n");
		goto error_no_pid;
	}
	new_state = nla_get_u32(info->attrs[WIMAX_GNL_RFKILL_STATE]);

	/* Execute the operation and send the result back to user space */
	result = wimax_rfkill(wimax_dev, new_state);
error_no_pid:
	dev_put(wimax_dev->net_dev);
error_no_wimax_dev:
	d_fnend(3, NULL, "(skb %p info %p) = %d\n", skb, info, result);
	return result;
}