Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  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
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
/*
 * Wireless Host Controller: Radio Control Interface (WHCI v0.95[2.3])
 * Radio Control command/event transport to the UWB stack
 *
 * Copyright (C) 2005-2006 Intel Corporation
 * 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.
 *
 *
 * Initialize and hook up the Radio Control interface.
 *
 * For each device probed, creates an 'struct whcrc' which contains
 * just the representation of the UWB Radio Controller, and the logic
 * for reading notifications and passing them to the UWB Core.
 *
 * So we initialize all of those, register the UWB Radio Controller
 * and setup the notification/event handle to pipe the notifications
 * to the UWB management Daemon.
 *
 * Once uwb_rc_add() is called, the UWB stack takes control, resets
 * the radio and readies the device to take commands the UWB
 * API/user-space.
 *
 * Note this driver is just a transport driver; the commands are
 * formed at the UWB stack and given to this driver who will deliver
 * them to the hw and transfer the replies/notifications back to the
 * UWB stack through the UWB daemon (UWBD).
 */
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/uwb.h>
#include <linux/uwb/whci.h>
#include <linux/uwb/umc.h>

#include "uwb-internal.h"

/**
 * Descriptor for an instance of the UWB Radio Control Driver that
 * attaches to the URC interface of the WHCI PCI card.
 *
 * Unless there is a lock specific to the 'data members', all access
 * is protected by uwb_rc->mutex.
 */
struct whcrc {
	struct umc_dev *umc_dev;
	struct uwb_rc *uwb_rc;		/* UWB host controller */

	unsigned long area;
	void __iomem *rc_base;
	size_t rc_len;
	spinlock_t irq_lock;

	void *evt_buf, *cmd_buf;
	dma_addr_t evt_dma_buf, cmd_dma_buf;
	wait_queue_head_t cmd_wq;
	struct work_struct event_work;
};

/**
 * Execute an UWB RC command on WHCI/RC
 *
 * @rc:       Instance of a Radio Controller that is a whcrc
 * @cmd:      Buffer containing the RCCB and payload to execute
 * @cmd_size: Size of the command buffer.
 *
 * We copy the command into whcrc->cmd_buf (as it is pretty and
 * aligned`and physically contiguous) and then press the right keys in
 * the controller's URCCMD register to get it to read it. We might
 * have to wait for the cmd_sem to be open to us.
 *
 * NOTE: rc's mutex has to be locked
 */
static int whcrc_cmd(struct uwb_rc *uwb_rc,
	      const struct uwb_rccb *cmd, size_t cmd_size)
{
	int result = 0;
	struct whcrc *whcrc = uwb_rc->priv;
	struct device *dev = &whcrc->umc_dev->dev;
	u32 urccmd;

	if (cmd_size >= 4096)
		return -EINVAL;

	/*
	 * If the URC is halted, then the hardware has reset itself.
	 * Attempt to recover by restarting the device and then return
	 * an error as it's likely that the current command isn't
	 * valid for a newly started RC.
	 */
	if (le_readl(whcrc->rc_base + URCSTS) & URCSTS_HALTED) {
		dev_err(dev, "requesting reset of halted radio controller\n");
		uwb_rc_reset_all(uwb_rc);
		return -EIO;
	}

	result = wait_event_timeout(whcrc->cmd_wq,
		!(le_readl(whcrc->rc_base + URCCMD) & URCCMD_ACTIVE), HZ/2);
	if (result == 0) {
		dev_err(dev, "device is not ready to execute commands\n");
		return -ETIMEDOUT;
	}

	memmove(whcrc->cmd_buf, cmd, cmd_size);
	le_writeq(whcrc->cmd_dma_buf, whcrc->rc_base + URCCMDADDR);

	spin_lock(&whcrc->irq_lock);
	urccmd = le_readl(whcrc->rc_base + URCCMD);
	urccmd &= ~(URCCMD_EARV | URCCMD_SIZE_MASK);
	le_writel(urccmd | URCCMD_ACTIVE | URCCMD_IWR | cmd_size,
		  whcrc->rc_base + URCCMD);
	spin_unlock(&whcrc->irq_lock);

	return 0;
}

static int whcrc_reset(struct uwb_rc *rc)
{
	struct whcrc *whcrc = rc->priv;

	return umc_controller_reset(whcrc->umc_dev);
}

/**
 * Reset event reception mechanism and tell hw we are ready to get more
 *
 * We have read all the events in the event buffer, so we are ready to
 * reset it to the beginning.
 *
 * This is only called during initialization or after an event buffer
 * has been retired.  This means we can be sure that event processing
 * is disabled and it's safe to update the URCEVTADDR register.
 *
 * There's no need to wait for the event processing to start as the
 * URC will not clear URCCMD_ACTIVE until (internal) event buffer
 * space is available.
 */
static
void whcrc_enable_events(struct whcrc *whcrc)
{
	u32 urccmd;

	le_writeq(whcrc->evt_dma_buf, whcrc->rc_base + URCEVTADDR);

	spin_lock(&whcrc->irq_lock);
	urccmd = le_readl(whcrc->rc_base + URCCMD) & ~URCCMD_ACTIVE;
	le_writel(urccmd | URCCMD_EARV, whcrc->rc_base + URCCMD);
	spin_unlock(&whcrc->irq_lock);
}

static void whcrc_event_work(struct work_struct *work)
{
	struct whcrc *whcrc = container_of(work, struct whcrc, event_work);
	size_t size;
	u64 urcevtaddr;

	urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
	size = urcevtaddr & URCEVTADDR_OFFSET_MASK;

	uwb_rc_neh_grok(whcrc->uwb_rc, whcrc->evt_buf, size);
	whcrc_enable_events(whcrc);
}

/**
 * Catch interrupts?
 *
 * We ack inmediately (and expect the hw to do the right thing and
 * raise another IRQ if things have changed :)
 */
static
irqreturn_t whcrc_irq_cb(int irq, void *_whcrc)
{
	struct whcrc *whcrc = _whcrc;
	struct device *dev = &whcrc->umc_dev->dev;
	u32 urcsts;

	urcsts = le_readl(whcrc->rc_base + URCSTS);
	if (!(urcsts & URCSTS_INT_MASK))
		return IRQ_NONE;
	le_writel(urcsts & URCSTS_INT_MASK, whcrc->rc_base + URCSTS);

	if (urcsts & URCSTS_HSE) {
		dev_err(dev, "host system error -- hardware halted\n");
		/* FIXME: do something sensible here */
		goto out;
	}
	if (urcsts & URCSTS_ER)
		schedule_work(&whcrc->event_work);
	if (urcsts & URCSTS_RCI)
		wake_up_all(&whcrc->cmd_wq);
out:
	return IRQ_HANDLED;
}


/**
 * Initialize a UMC RC interface: map regions, get (shared) IRQ
 */
static
int whcrc_setup_rc_umc(struct whcrc *whcrc)
{
	int result = 0;
	struct device *dev = &whcrc->umc_dev->dev;
	struct umc_dev *umc_dev = whcrc->umc_dev;

	whcrc->area = umc_dev->resource.start;
	whcrc->rc_len = umc_dev->resource.end - umc_dev->resource.start + 1;
	result = -EBUSY;
	if (request_mem_region(whcrc->area, whcrc->rc_len, KBUILD_MODNAME) == NULL) {
		dev_err(dev, "can't request URC region (%zu bytes @ 0x%lx): %d\n",
			whcrc->rc_len, whcrc->area, result);
		goto error_request_region;
	}

	whcrc->rc_base = ioremap_nocache(whcrc->area, whcrc->rc_len);
	if (whcrc->rc_base == NULL) {
		dev_err(dev, "can't ioremap registers (%zu bytes @ 0x%lx): %d\n",
			whcrc->rc_len, whcrc->area, result);
		goto error_ioremap_nocache;
	}

	result = request_irq(umc_dev->irq, whcrc_irq_cb, IRQF_SHARED,
			     KBUILD_MODNAME, whcrc);
	if (result < 0) {
		dev_err(dev, "can't allocate IRQ %d: %d\n",
			umc_dev->irq, result);
		goto error_request_irq;
	}

	result = -ENOMEM;
	whcrc->cmd_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
					    &whcrc->cmd_dma_buf, GFP_KERNEL);
	if (whcrc->cmd_buf == NULL) {
		dev_err(dev, "Can't allocate cmd transfer buffer\n");
		goto error_cmd_buffer;
	}

	whcrc->evt_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
					    &whcrc->evt_dma_buf, GFP_KERNEL);
	if (whcrc->evt_buf == NULL) {
		dev_err(dev, "Can't allocate evt transfer buffer\n");
		goto error_evt_buffer;
	}
	return 0;

error_evt_buffer:
	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
			  whcrc->cmd_dma_buf);
error_cmd_buffer:
	free_irq(umc_dev->irq, whcrc);
error_request_irq:
	iounmap(whcrc->rc_base);
error_ioremap_nocache:
	release_mem_region(whcrc->area, whcrc->rc_len);
error_request_region:
	return result;
}


/**
 * Release RC's UMC resources
 */
static
void whcrc_release_rc_umc(struct whcrc *whcrc)
{
	struct umc_dev *umc_dev = whcrc->umc_dev;

	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->evt_buf,
			  whcrc->evt_dma_buf);
	dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
			  whcrc->cmd_dma_buf);
	free_irq(umc_dev->irq, whcrc);
	iounmap(whcrc->rc_base);
	release_mem_region(whcrc->area, whcrc->rc_len);
}


/**
 * whcrc_start_rc - start a WHCI radio controller
 * @whcrc: the radio controller to start
 *
 * Reset the UMC device, start the radio controller, enable events and
 * finally enable interrupts.
 */
static int whcrc_start_rc(struct uwb_rc *rc)
{
	struct whcrc *whcrc = rc->priv;
	struct device *dev = &whcrc->umc_dev->dev;

	/* Reset the thing */
	le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);
	if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,
			  5000, "hardware reset") < 0)
		return -EBUSY;

	/* Set the event buffer, start the controller (enable IRQs later) */
	le_writel(0, whcrc->rc_base + URCINTR);
	le_writel(URCCMD_RS, whcrc->rc_base + URCCMD);
	if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,
			  5000, "radio controller start") < 0)
		return -ETIMEDOUT;
	whcrc_enable_events(whcrc);
	le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);
	return 0;
}


/**
 * whcrc_stop_rc - stop a WHCI radio controller
 * @whcrc: the radio controller to stop
 *
 * Disable interrupts and cancel any pending event processing work
 * before clearing the Run/Stop bit.
 */
static
void whcrc_stop_rc(struct uwb_rc *rc)
{
	struct whcrc *whcrc = rc->priv;
	struct umc_dev *umc_dev = whcrc->umc_dev;

	le_writel(0, whcrc->rc_base + URCINTR);
	cancel_work_sync(&whcrc->event_work);

	le_writel(0, whcrc->rc_base + URCCMD);
	whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,
		      URCSTS_HALTED, URCSTS_HALTED, 100, "radio controller stop");
}

static void whcrc_init(struct whcrc *whcrc)
{
	spin_lock_init(&whcrc->irq_lock);
	init_waitqueue_head(&whcrc->cmd_wq);
	INIT_WORK(&whcrc->event_work, whcrc_event_work);
}

/**
 * Initialize the radio controller.
 *
 * NOTE: we setup whcrc->uwb_rc before calling uwb_rc_add(); in the
 *       IRQ handler we use that to determine if the hw is ready to
 *       handle events. Looks like a race condition, but it really is
 *       not.
 */
static
int whcrc_probe(struct umc_dev *umc_dev)
{
	int result;
	struct uwb_rc *uwb_rc;
	struct whcrc *whcrc;
	struct device *dev = &umc_dev->dev;

	result = -ENOMEM;
	uwb_rc = uwb_rc_alloc();
	if (uwb_rc == NULL) {
		dev_err(dev, "unable to allocate RC instance\n");
		goto error_rc_alloc;
	}
	whcrc = kzalloc(sizeof(*whcrc), GFP_KERNEL);
	if (whcrc == NULL) {
		dev_err(dev, "unable to allocate WHC-RC instance\n");
		goto error_alloc;
	}
	whcrc_init(whcrc);
	whcrc->umc_dev = umc_dev;

	result = whcrc_setup_rc_umc(whcrc);
	if (result < 0) {
		dev_err(dev, "Can't setup RC UMC interface: %d\n", result);
		goto error_setup_rc_umc;
	}
	whcrc->uwb_rc = uwb_rc;

	uwb_rc->owner = THIS_MODULE;
	uwb_rc->cmd   = whcrc_cmd;
	uwb_rc->reset = whcrc_reset;
	uwb_rc->start = whcrc_start_rc;
	uwb_rc->stop  = whcrc_stop_rc;

	result = uwb_rc_add(uwb_rc, dev, whcrc);
	if (result < 0)
		goto error_rc_add;
	umc_set_drvdata(umc_dev, whcrc);
	return 0;

error_rc_add:
	whcrc_release_rc_umc(whcrc);
error_setup_rc_umc:
	kfree(whcrc);
error_alloc:
	uwb_rc_put(uwb_rc);
error_rc_alloc:
	return result;
}

/**
 * Clean up the radio control resources
 *
 * When we up the command semaphore, everybody possibly held trying to
 * execute a command should be granted entry and then they'll see the
 * host is quiescing and up it (so it will chain to the next waiter).
 * This should not happen (in any case), as we can only remove when
 * there are no handles open...
 */
static void whcrc_remove(struct umc_dev *umc_dev)
{
	struct whcrc *whcrc = umc_get_drvdata(umc_dev);
	struct uwb_rc *uwb_rc = whcrc->uwb_rc;

	umc_set_drvdata(umc_dev, NULL);
	uwb_rc_rm(uwb_rc);
	whcrc_release_rc_umc(whcrc);
	kfree(whcrc);
	uwb_rc_put(uwb_rc);
}

static int whcrc_pre_reset(struct umc_dev *umc)
{
	struct whcrc *whcrc = umc_get_drvdata(umc);
	struct uwb_rc *uwb_rc = whcrc->uwb_rc;

	uwb_rc_pre_reset(uwb_rc);
	return 0;
}

static int whcrc_post_reset(struct umc_dev *umc)
{
	struct whcrc *whcrc = umc_get_drvdata(umc);
	struct uwb_rc *uwb_rc = whcrc->uwb_rc;

	return uwb_rc_post_reset(uwb_rc);
}

/* PCI device ID's that we handle [so it gets loaded] */
static struct pci_device_id whcrc_id_table[] = {
	{ PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
	{ /* empty last entry */ }
};
MODULE_DEVICE_TABLE(pci, whcrc_id_table);

static struct umc_driver whcrc_driver = {
	.name       = "whc-rc",
	.cap_id     = UMC_CAP_ID_WHCI_RC,
	.probe      = whcrc_probe,
	.remove     = whcrc_remove,
	.pre_reset  = whcrc_pre_reset,
	.post_reset = whcrc_post_reset,
};

static int __init whcrc_driver_init(void)
{
	return umc_driver_register(&whcrc_driver);
}
module_init(whcrc_driver_init);

static void __exit whcrc_driver_exit(void)
{
	umc_driver_unregister(&whcrc_driver);
}
module_exit(whcrc_driver_exit);

MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver");
MODULE_LICENSE("GPL");