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Linux/drivers/uwb/whc-rc.c

  1 /*
  2  * Wireless Host Controller: Radio Control Interface (WHCI v0.95[2.3])
  3  * Radio Control command/event transport to the UWB stack
  4  *
  5  * Copyright (C) 2005-2006 Intel Corporation
  6  * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>
  7  *
  8  * This program is free software; you can redistribute it and/or
  9  * modify it under the terms of the GNU General Public License version
 10  * 2 as published by the Free Software Foundation.
 11  *
 12  * This program is distributed in the hope that it will be useful,
 13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15  * GNU General Public License for more details.
 16  *
 17  * You should have received a copy of the GNU General Public License
 18  * along with this program; if not, write to the Free Software
 19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 20  * 02110-1301, USA.
 21  *
 22  *
 23  * Initialize and hook up the Radio Control interface.
 24  *
 25  * For each device probed, creates an 'struct whcrc' which contains
 26  * just the representation of the UWB Radio Controller, and the logic
 27  * for reading notifications and passing them to the UWB Core.
 28  *
 29  * So we initialize all of those, register the UWB Radio Controller
 30  * and setup the notification/event handle to pipe the notifications
 31  * to the UWB management Daemon.
 32  *
 33  * Once uwb_rc_add() is called, the UWB stack takes control, resets
 34  * the radio and readies the device to take commands the UWB
 35  * API/user-space.
 36  *
 37  * Note this driver is just a transport driver; the commands are
 38  * formed at the UWB stack and given to this driver who will deliver
 39  * them to the hw and transfer the replies/notifications back to the
 40  * UWB stack through the UWB daemon (UWBD).
 41  */
 42 #include <linux/init.h>
 43 #include <linux/module.h>
 44 #include <linux/pci.h>
 45 #include <linux/sched.h>
 46 #include <linux/dma-mapping.h>
 47 #include <linux/interrupt.h>
 48 #include <linux/slab.h>
 49 #include <linux/workqueue.h>
 50 #include <linux/uwb.h>
 51 #include <linux/uwb/whci.h>
 52 #include <linux/uwb/umc.h>
 53 
 54 #include "uwb-internal.h"
 55 
 56 /**
 57  * Descriptor for an instance of the UWB Radio Control Driver that
 58  * attaches to the URC interface of the WHCI PCI card.
 59  *
 60  * Unless there is a lock specific to the 'data members', all access
 61  * is protected by uwb_rc->mutex.
 62  */
 63 struct whcrc {
 64         struct umc_dev *umc_dev;
 65         struct uwb_rc *uwb_rc;          /* UWB host controller */
 66 
 67         unsigned long area;
 68         void __iomem *rc_base;
 69         size_t rc_len;
 70         spinlock_t irq_lock;
 71 
 72         void *evt_buf, *cmd_buf;
 73         dma_addr_t evt_dma_buf, cmd_dma_buf;
 74         wait_queue_head_t cmd_wq;
 75         struct work_struct event_work;
 76 };
 77 
 78 /**
 79  * Execute an UWB RC command on WHCI/RC
 80  *
 81  * @rc:       Instance of a Radio Controller that is a whcrc
 82  * @cmd:      Buffer containing the RCCB and payload to execute
 83  * @cmd_size: Size of the command buffer.
 84  *
 85  * We copy the command into whcrc->cmd_buf (as it is pretty and
 86  * aligned`and physically contiguous) and then press the right keys in
 87  * the controller's URCCMD register to get it to read it. We might
 88  * have to wait for the cmd_sem to be open to us.
 89  *
 90  * NOTE: rc's mutex has to be locked
 91  */
 92 static int whcrc_cmd(struct uwb_rc *uwb_rc,
 93               const struct uwb_rccb *cmd, size_t cmd_size)
 94 {
 95         int result = 0;
 96         struct whcrc *whcrc = uwb_rc->priv;
 97         struct device *dev = &whcrc->umc_dev->dev;
 98         u32 urccmd;
 99 
100         if (cmd_size >= 4096)
101                 return -EINVAL;
102 
103         /*
104          * If the URC is halted, then the hardware has reset itself.
105          * Attempt to recover by restarting the device and then return
106          * an error as it's likely that the current command isn't
107          * valid for a newly started RC.
108          */
109         if (le_readl(whcrc->rc_base + URCSTS) & URCSTS_HALTED) {
110                 dev_err(dev, "requesting reset of halted radio controller\n");
111                 uwb_rc_reset_all(uwb_rc);
112                 return -EIO;
113         }
114 
115         result = wait_event_timeout(whcrc->cmd_wq,
116                 !(le_readl(whcrc->rc_base + URCCMD) & URCCMD_ACTIVE), HZ/2);
117         if (result == 0) {
118                 dev_err(dev, "device is not ready to execute commands\n");
119                 return -ETIMEDOUT;
120         }
121 
122         memmove(whcrc->cmd_buf, cmd, cmd_size);
123         le_writeq(whcrc->cmd_dma_buf, whcrc->rc_base + URCCMDADDR);
124 
125         spin_lock(&whcrc->irq_lock);
126         urccmd = le_readl(whcrc->rc_base + URCCMD);
127         urccmd &= ~(URCCMD_EARV | URCCMD_SIZE_MASK);
128         le_writel(urccmd | URCCMD_ACTIVE | URCCMD_IWR | cmd_size,
129                   whcrc->rc_base + URCCMD);
130         spin_unlock(&whcrc->irq_lock);
131 
132         return 0;
133 }
134 
135 static int whcrc_reset(struct uwb_rc *rc)
136 {
137         struct whcrc *whcrc = rc->priv;
138 
139         return umc_controller_reset(whcrc->umc_dev);
140 }
141 
142 /**
143  * Reset event reception mechanism and tell hw we are ready to get more
144  *
145  * We have read all the events in the event buffer, so we are ready to
146  * reset it to the beginning.
147  *
148  * This is only called during initialization or after an event buffer
149  * has been retired.  This means we can be sure that event processing
150  * is disabled and it's safe to update the URCEVTADDR register.
151  *
152  * There's no need to wait for the event processing to start as the
153  * URC will not clear URCCMD_ACTIVE until (internal) event buffer
154  * space is available.
155  */
156 static
157 void whcrc_enable_events(struct whcrc *whcrc)
158 {
159         u32 urccmd;
160 
161         le_writeq(whcrc->evt_dma_buf, whcrc->rc_base + URCEVTADDR);
162 
163         spin_lock(&whcrc->irq_lock);
164         urccmd = le_readl(whcrc->rc_base + URCCMD) & ~URCCMD_ACTIVE;
165         le_writel(urccmd | URCCMD_EARV, whcrc->rc_base + URCCMD);
166         spin_unlock(&whcrc->irq_lock);
167 }
168 
169 static void whcrc_event_work(struct work_struct *work)
170 {
171         struct whcrc *whcrc = container_of(work, struct whcrc, event_work);
172         size_t size;
173         u64 urcevtaddr;
174 
175         urcevtaddr = le_readq(whcrc->rc_base + URCEVTADDR);
176         size = urcevtaddr & URCEVTADDR_OFFSET_MASK;
177 
178         uwb_rc_neh_grok(whcrc->uwb_rc, whcrc->evt_buf, size);
179         whcrc_enable_events(whcrc);
180 }
181 
182 /**
183  * Catch interrupts?
184  *
185  * We ack inmediately (and expect the hw to do the right thing and
186  * raise another IRQ if things have changed :)
187  */
188 static
189 irqreturn_t whcrc_irq_cb(int irq, void *_whcrc)
190 {
191         struct whcrc *whcrc = _whcrc;
192         struct device *dev = &whcrc->umc_dev->dev;
193         u32 urcsts;
194 
195         urcsts = le_readl(whcrc->rc_base + URCSTS);
196         if (!(urcsts & URCSTS_INT_MASK))
197                 return IRQ_NONE;
198         le_writel(urcsts & URCSTS_INT_MASK, whcrc->rc_base + URCSTS);
199 
200         if (urcsts & URCSTS_HSE) {
201                 dev_err(dev, "host system error -- hardware halted\n");
202                 /* FIXME: do something sensible here */
203                 goto out;
204         }
205         if (urcsts & URCSTS_ER)
206                 schedule_work(&whcrc->event_work);
207         if (urcsts & URCSTS_RCI)
208                 wake_up_all(&whcrc->cmd_wq);
209 out:
210         return IRQ_HANDLED;
211 }
212 
213 
214 /**
215  * Initialize a UMC RC interface: map regions, get (shared) IRQ
216  */
217 static
218 int whcrc_setup_rc_umc(struct whcrc *whcrc)
219 {
220         int result = 0;
221         struct device *dev = &whcrc->umc_dev->dev;
222         struct umc_dev *umc_dev = whcrc->umc_dev;
223 
224         whcrc->area = umc_dev->resource.start;
225         whcrc->rc_len = resource_size(&umc_dev->resource);
226         result = -EBUSY;
227         if (request_mem_region(whcrc->area, whcrc->rc_len, KBUILD_MODNAME) == NULL) {
228                 dev_err(dev, "can't request URC region (%zu bytes @ 0x%lx): %d\n",
229                         whcrc->rc_len, whcrc->area, result);
230                 goto error_request_region;
231         }
232 
233         whcrc->rc_base = ioremap_nocache(whcrc->area, whcrc->rc_len);
234         if (whcrc->rc_base == NULL) {
235                 dev_err(dev, "can't ioremap registers (%zu bytes @ 0x%lx): %d\n",
236                         whcrc->rc_len, whcrc->area, result);
237                 goto error_ioremap_nocache;
238         }
239 
240         result = request_irq(umc_dev->irq, whcrc_irq_cb, IRQF_SHARED,
241                              KBUILD_MODNAME, whcrc);
242         if (result < 0) {
243                 dev_err(dev, "can't allocate IRQ %d: %d\n",
244                         umc_dev->irq, result);
245                 goto error_request_irq;
246         }
247 
248         result = -ENOMEM;
249         whcrc->cmd_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
250                                             &whcrc->cmd_dma_buf, GFP_KERNEL);
251         if (whcrc->cmd_buf == NULL) {
252                 dev_err(dev, "Can't allocate cmd transfer buffer\n");
253                 goto error_cmd_buffer;
254         }
255 
256         whcrc->evt_buf = dma_alloc_coherent(&umc_dev->dev, PAGE_SIZE,
257                                             &whcrc->evt_dma_buf, GFP_KERNEL);
258         if (whcrc->evt_buf == NULL) {
259                 dev_err(dev, "Can't allocate evt transfer buffer\n");
260                 goto error_evt_buffer;
261         }
262         return 0;
263 
264 error_evt_buffer:
265         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
266                           whcrc->cmd_dma_buf);
267 error_cmd_buffer:
268         free_irq(umc_dev->irq, whcrc);
269 error_request_irq:
270         iounmap(whcrc->rc_base);
271 error_ioremap_nocache:
272         release_mem_region(whcrc->area, whcrc->rc_len);
273 error_request_region:
274         return result;
275 }
276 
277 
278 /**
279  * Release RC's UMC resources
280  */
281 static
282 void whcrc_release_rc_umc(struct whcrc *whcrc)
283 {
284         struct umc_dev *umc_dev = whcrc->umc_dev;
285 
286         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->evt_buf,
287                           whcrc->evt_dma_buf);
288         dma_free_coherent(&umc_dev->dev, PAGE_SIZE, whcrc->cmd_buf,
289                           whcrc->cmd_dma_buf);
290         free_irq(umc_dev->irq, whcrc);
291         iounmap(whcrc->rc_base);
292         release_mem_region(whcrc->area, whcrc->rc_len);
293 }
294 
295 
296 /**
297  * whcrc_start_rc - start a WHCI radio controller
298  * @whcrc: the radio controller to start
299  *
300  * Reset the UMC device, start the radio controller, enable events and
301  * finally enable interrupts.
302  */
303 static int whcrc_start_rc(struct uwb_rc *rc)
304 {
305         struct whcrc *whcrc = rc->priv;
306         struct device *dev = &whcrc->umc_dev->dev;
307 
308         /* Reset the thing */
309         le_writel(URCCMD_RESET, whcrc->rc_base + URCCMD);
310         if (whci_wait_for(dev, whcrc->rc_base + URCCMD, URCCMD_RESET, 0,
311                           5000, "hardware reset") < 0)
312                 return -EBUSY;
313 
314         /* Set the event buffer, start the controller (enable IRQs later) */
315         le_writel(0, whcrc->rc_base + URCINTR);
316         le_writel(URCCMD_RS, whcrc->rc_base + URCCMD);
317         if (whci_wait_for(dev, whcrc->rc_base + URCSTS, URCSTS_HALTED, 0,
318                           5000, "radio controller start") < 0)
319                 return -ETIMEDOUT;
320         whcrc_enable_events(whcrc);
321         le_writel(URCINTR_EN_ALL, whcrc->rc_base + URCINTR);
322         return 0;
323 }
324 
325 
326 /**
327  * whcrc_stop_rc - stop a WHCI radio controller
328  * @whcrc: the radio controller to stop
329  *
330  * Disable interrupts and cancel any pending event processing work
331  * before clearing the Run/Stop bit.
332  */
333 static
334 void whcrc_stop_rc(struct uwb_rc *rc)
335 {
336         struct whcrc *whcrc = rc->priv;
337         struct umc_dev *umc_dev = whcrc->umc_dev;
338 
339         le_writel(0, whcrc->rc_base + URCINTR);
340         cancel_work_sync(&whcrc->event_work);
341 
342         le_writel(0, whcrc->rc_base + URCCMD);
343         whci_wait_for(&umc_dev->dev, whcrc->rc_base + URCSTS,
344                       URCSTS_HALTED, URCSTS_HALTED, 100, "radio controller stop");
345 }
346 
347 static void whcrc_init(struct whcrc *whcrc)
348 {
349         spin_lock_init(&whcrc->irq_lock);
350         init_waitqueue_head(&whcrc->cmd_wq);
351         INIT_WORK(&whcrc->event_work, whcrc_event_work);
352 }
353 
354 /**
355  * Initialize the radio controller.
356  *
357  * NOTE: we setup whcrc->uwb_rc before calling uwb_rc_add(); in the
358  *       IRQ handler we use that to determine if the hw is ready to
359  *       handle events. Looks like a race condition, but it really is
360  *       not.
361  */
362 static
363 int whcrc_probe(struct umc_dev *umc_dev)
364 {
365         int result;
366         struct uwb_rc *uwb_rc;
367         struct whcrc *whcrc;
368         struct device *dev = &umc_dev->dev;
369 
370         result = -ENOMEM;
371         uwb_rc = uwb_rc_alloc();
372         if (uwb_rc == NULL) {
373                 dev_err(dev, "unable to allocate RC instance\n");
374                 goto error_rc_alloc;
375         }
376         whcrc = kzalloc(sizeof(*whcrc), GFP_KERNEL);
377         if (whcrc == NULL) {
378                 dev_err(dev, "unable to allocate WHC-RC instance\n");
379                 goto error_alloc;
380         }
381         whcrc_init(whcrc);
382         whcrc->umc_dev = umc_dev;
383 
384         result = whcrc_setup_rc_umc(whcrc);
385         if (result < 0) {
386                 dev_err(dev, "Can't setup RC UMC interface: %d\n", result);
387                 goto error_setup_rc_umc;
388         }
389         whcrc->uwb_rc = uwb_rc;
390 
391         uwb_rc->owner = THIS_MODULE;
392         uwb_rc->cmd   = whcrc_cmd;
393         uwb_rc->reset = whcrc_reset;
394         uwb_rc->start = whcrc_start_rc;
395         uwb_rc->stop  = whcrc_stop_rc;
396 
397         result = uwb_rc_add(uwb_rc, dev, whcrc);
398         if (result < 0)
399                 goto error_rc_add;
400         umc_set_drvdata(umc_dev, whcrc);
401         return 0;
402 
403 error_rc_add:
404         whcrc_release_rc_umc(whcrc);
405 error_setup_rc_umc:
406         kfree(whcrc);
407 error_alloc:
408         uwb_rc_put(uwb_rc);
409 error_rc_alloc:
410         return result;
411 }
412 
413 /**
414  * Clean up the radio control resources
415  *
416  * When we up the command semaphore, everybody possibly held trying to
417  * execute a command should be granted entry and then they'll see the
418  * host is quiescing and up it (so it will chain to the next waiter).
419  * This should not happen (in any case), as we can only remove when
420  * there are no handles open...
421  */
422 static void whcrc_remove(struct umc_dev *umc_dev)
423 {
424         struct whcrc *whcrc = umc_get_drvdata(umc_dev);
425         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
426 
427         umc_set_drvdata(umc_dev, NULL);
428         uwb_rc_rm(uwb_rc);
429         whcrc_release_rc_umc(whcrc);
430         kfree(whcrc);
431         uwb_rc_put(uwb_rc);
432 }
433 
434 static int whcrc_pre_reset(struct umc_dev *umc)
435 {
436         struct whcrc *whcrc = umc_get_drvdata(umc);
437         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
438 
439         uwb_rc_pre_reset(uwb_rc);
440         return 0;
441 }
442 
443 static int whcrc_post_reset(struct umc_dev *umc)
444 {
445         struct whcrc *whcrc = umc_get_drvdata(umc);
446         struct uwb_rc *uwb_rc = whcrc->uwb_rc;
447 
448         return uwb_rc_post_reset(uwb_rc);
449 }
450 
451 /* PCI device ID's that we handle [so it gets loaded] */
452 static struct pci_device_id __used whcrc_id_table[] = {
453         { PCI_DEVICE_CLASS(PCI_CLASS_WIRELESS_WHCI, ~0) },
454         { /* empty last entry */ }
455 };
456 MODULE_DEVICE_TABLE(pci, whcrc_id_table);
457 
458 static struct umc_driver whcrc_driver = {
459         .name       = "whc-rc",
460         .cap_id     = UMC_CAP_ID_WHCI_RC,
461         .probe      = whcrc_probe,
462         .remove     = whcrc_remove,
463         .pre_reset  = whcrc_pre_reset,
464         .post_reset = whcrc_post_reset,
465 };
466 
467 static int __init whcrc_driver_init(void)
468 {
469         return umc_driver_register(&whcrc_driver);
470 }
471 module_init(whcrc_driver_init);
472 
473 static void __exit whcrc_driver_exit(void)
474 {
475         umc_driver_unregister(&whcrc_driver);
476 }
477 module_exit(whcrc_driver_exit);
478 
479 MODULE_AUTHOR("Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>");
480 MODULE_DESCRIPTION("Wireless Host Controller Radio Control Driver");
481 MODULE_LICENSE("GPL");
482 

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