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  * (C) Copyright David Brownell 2000-2002
  3  *
  4  * This program is free software; you can redistribute it and/or modify it
  5  * under the terms of the GNU General Public License as published by the
  6  * Free Software Foundation; either version 2 of the License, or (at your
  7  * option) any later version.
  8  *
  9  * This program is distributed in the hope that it will be useful, but
 10  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 11  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * for more details.
 13  *
 14  * You should have received a copy of the GNU General Public License
 15  * along with this program; if not, write to the Free Software Foundation,
 16  * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 17  */
 18 
 19 #include <linux/kernel.h>
 20 #include <linux/module.h>
 21 #include <linux/pci.h>
 22 #include <linux/usb.h>
 23 
 24 #include <asm/io.h>
 25 #include <asm/irq.h>
 26 
 27 #ifdef CONFIG_PPC_PMAC
 28 #include <asm/machdep.h>
 29 #include <asm/pmac_feature.h>
 30 #include <asm/pci-bridge.h>
 31 #include <asm/prom.h>
 32 #endif
 33 
 34 #include "usb.h"
 35 #include "hcd.h"
 36 
 37 
 38 /* PCI-based HCs are common, but plenty of non-PCI HCs are used too */
 39 
 40 
 41 /*-------------------------------------------------------------------------*/
 42 
 43 /* configure so an HC device and id are always provided */
 44 /* always called with process context; sleeping is OK */
 45 
 46 /**
 47  * usb_hcd_pci_probe - initialize PCI-based HCDs
 48  * @dev: USB Host Controller being probed
 49  * @id: pci hotplug id connecting controller to HCD framework
 50  * Context: !in_interrupt()
 51  *
 52  * Allocates basic PCI resources for this USB host controller, and
 53  * then invokes the start() method for the HCD associated with it
 54  * through the hotplug entry's driver_data.
 55  *
 56  * Store this function in the HCD's struct pci_driver as probe().
 57  */
 58 int usb_hcd_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
 59 {
 60         struct hc_driver        *driver;
 61         struct usb_hcd          *hcd;
 62         int                     retval;
 63 
 64         if (usb_disabled())
 65                 return -ENODEV;
 66 
 67         if (!id)
 68                 return -EINVAL;
 69         driver = (struct hc_driver *)id->driver_data;
 70         if (!driver)
 71                 return -EINVAL;
 72 
 73         if (pci_enable_device(dev) < 0)
 74                 return -ENODEV;
 75         dev->current_state = PCI_D0;
 76         dev->dev.power.power_state = PMSG_ON;
 77 
 78         if (!dev->irq) {
 79                 dev_err(&dev->dev,
 80                         "Found HC with no IRQ.  Check BIOS/PCI %s setup!\n",
 81                         pci_name(dev));
 82                 retval = -ENODEV;
 83                 goto err1;
 84         }
 85 
 86         hcd = usb_create_hcd(driver, &dev->dev, pci_name(dev));
 87         if (!hcd) {
 88                 retval = -ENOMEM;
 89                 goto err1;
 90         }
 91 
 92         if (driver->flags & HCD_MEMORY) {
 93                 /* EHCI, OHCI */
 94                 hcd->rsrc_start = pci_resource_start(dev, 0);
 95                 hcd->rsrc_len = pci_resource_len(dev, 0);
 96                 if (!request_mem_region(hcd->rsrc_start, hcd->rsrc_len,
 97                                 driver->description)) {
 98                         dev_dbg(&dev->dev, "controller already in use\n");
 99                         retval = -EBUSY;
100                         goto err2;
101                 }
102                 hcd->regs = ioremap_nocache(hcd->rsrc_start, hcd->rsrc_len);
103                 if (hcd->regs == NULL) {
104                         dev_dbg(&dev->dev, "error mapping memory\n");
105                         retval = -EFAULT;
106                         goto err3;
107                 }
108 
109         } else {
110                 /* UHCI */
111                 int     region;
112 
113                 for (region = 0; region < PCI_ROM_RESOURCE; region++) {
114                         if (!(pci_resource_flags(dev, region) &
115                                         IORESOURCE_IO))
116                                 continue;
117 
118                         hcd->rsrc_start = pci_resource_start(dev, region);
119                         hcd->rsrc_len = pci_resource_len(dev, region);
120                         if (request_region(hcd->rsrc_start, hcd->rsrc_len,
121                                         driver->description))
122                                 break;
123                 }
124                 if (region == PCI_ROM_RESOURCE) {
125                         dev_dbg(&dev->dev, "no i/o regions available\n");
126                         retval = -EBUSY;
127                         goto err1;
128                 }
129         }
130 
131         pci_set_master(dev);
132 
133         retval = usb_add_hcd(hcd, dev->irq, IRQF_DISABLED | IRQF_SHARED);
134         if (retval != 0)
135                 goto err4;
136         return retval;
137 
138  err4:
139         if (driver->flags & HCD_MEMORY) {
140                 iounmap(hcd->regs);
141  err3:
142                 release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
143         } else
144                 release_region(hcd->rsrc_start, hcd->rsrc_len);
145  err2:
146         usb_put_hcd(hcd);
147  err1:
148         pci_disable_device(dev);
149         dev_err(&dev->dev, "init %s fail, %d\n", pci_name(dev), retval);
150         return retval;
151 }
152 EXPORT_SYMBOL_GPL(usb_hcd_pci_probe);
153 
154 
155 /* may be called without controller electrically present */
156 /* may be called with controller, bus, and devices active */
157 
158 /**
159  * usb_hcd_pci_remove - shutdown processing for PCI-based HCDs
160  * @dev: USB Host Controller being removed
161  * Context: !in_interrupt()
162  *
163  * Reverses the effect of usb_hcd_pci_probe(), first invoking
164  * the HCD's stop() method.  It is always called from a thread
165  * context, normally "rmmod", "apmd", or something similar.
166  *
167  * Store this function in the HCD's struct pci_driver as remove().
168  */
169 void usb_hcd_pci_remove(struct pci_dev *dev)
170 {
171         struct usb_hcd          *hcd;
172 
173         hcd = pci_get_drvdata(dev);
174         if (!hcd)
175                 return;
176 
177         usb_remove_hcd(hcd);
178         if (hcd->driver->flags & HCD_MEMORY) {
179                 iounmap(hcd->regs);
180                 release_mem_region(hcd->rsrc_start, hcd->rsrc_len);
181         } else {
182                 release_region(hcd->rsrc_start, hcd->rsrc_len);
183         }
184         usb_put_hcd(hcd);
185         pci_disable_device(dev);
186 }
187 EXPORT_SYMBOL_GPL(usb_hcd_pci_remove);
188 
189 
190 #ifdef  CONFIG_PM
191 
192 /**
193  * usb_hcd_pci_suspend - power management suspend of a PCI-based HCD
194  * @dev: USB Host Controller being suspended
195  * @message: semantics in flux
196  *
197  * Store this function in the HCD's struct pci_driver as suspend().
198  */
199 int usb_hcd_pci_suspend(struct pci_dev *dev, pm_message_t message)
200 {
201         struct usb_hcd          *hcd;
202         int                     retval = 0;
203         int                     has_pci_pm;
204 
205         hcd = pci_get_drvdata(dev);
206 
207         /* Root hub suspend should have stopped all downstream traffic,
208          * and all bus master traffic.  And done so for both the interface
209          * and the stub usb_device (which we check here).  But maybe it
210          * didn't; writing sysfs power/state files ignores such rules...
211          *
212          * We must ignore the FREEZE vs SUSPEND distinction here, because
213          * otherwise the swsusp will save (and restore) garbage state.
214          */
215         if (!(hcd->state == HC_STATE_SUSPENDED ||
216                         hcd->state == HC_STATE_HALT))
217                 return -EBUSY;
218 
219         if (hcd->driver->suspend) {
220                 retval = hcd->driver->suspend(hcd, message);
221                 suspend_report_result(hcd->driver->suspend, retval);
222                 if (retval)
223                         goto done;
224         }
225         synchronize_irq(dev->irq);
226 
227         /* FIXME until the generic PM interfaces change a lot more, this
228          * can't use PCI D1 and D2 states.  For example, the confusion
229          * between messages and states will need to vanish, and messages
230          * will need to provide a target system state again.
231          *
232          * It'll be important to learn characteristics of the target state,
233          * especially on embedded hardware where the HCD will often be in
234          * charge of an external VBUS power supply and one or more clocks.
235          * Some target system states will leave them active; others won't.
236          * (With PCI, that's often handled by platform BIOS code.)
237          */
238 
239         /* even when the PCI layer rejects some of the PCI calls
240          * below, HCs can try global suspend and reduce DMA traffic.
241          * PM-sensitive HCDs may already have done this.
242          */
243         has_pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM);
244 
245         /* Downstream ports from this root hub should already be quiesced, so
246          * there will be no DMA activity.  Now we can shut down the upstream
247          * link (except maybe for PME# resume signaling) and enter some PCI
248          * low power state, if the hardware allows.
249          */
250         if (hcd->state == HC_STATE_SUSPENDED) {
251 
252                 /* no DMA or IRQs except when HC is active */
253                 if (dev->current_state == PCI_D0) {
254                         pci_save_state(dev);
255                         pci_disable_device(dev);
256                 }
257 
258                 if (message.event == PM_EVENT_FREEZE ||
259                                 message.event == PM_EVENT_PRETHAW) {
260                         dev_dbg(hcd->self.controller, "--> no state change\n");
261                         goto done;
262                 }
263 
264                 if (!has_pci_pm) {
265                         dev_dbg(hcd->self.controller, "--> PCI D0/legacy\n");
266                         goto done;
267                 }
268 
269                 /* NOTE:  dev->current_state becomes nonzero only here, and
270                  * only for devices that support PCI PM.  Also, exiting
271                  * PCI_D3 (but not PCI_D1 or PCI_D2) is allowed to reset
272                  * some device state (e.g. as part of clock reinit).
273                  */
274                 retval = pci_set_power_state(dev, PCI_D3hot);
275                 suspend_report_result(pci_set_power_state, retval);
276                 if (retval == 0) {
277                         int wake = device_can_wakeup(&hcd->self.root_hub->dev);
278 
279                         wake = wake && device_may_wakeup(hcd->self.controller);
280 
281                         dev_dbg(hcd->self.controller, "--> PCI D3%s\n",
282                                         wake ? "/wakeup" : "");
283 
284                         /* Ignore these return values.  We rely on pci code to
285                          * reject requests the hardware can't implement, rather
286                          * than coding the same thing.
287                          */
288                         (void) pci_enable_wake(dev, PCI_D3hot, wake);
289                         (void) pci_enable_wake(dev, PCI_D3cold, wake);
290                 } else {
291                         dev_dbg(&dev->dev, "PCI D3 suspend fail, %d\n",
292                                         retval);
293                         (void) usb_hcd_pci_resume(dev);
294                 }
295 
296         } else if (hcd->state != HC_STATE_HALT) {
297                 dev_dbg(hcd->self.controller, "hcd state %d; not suspended\n",
298                         hcd->state);
299                 WARN_ON(1);
300                 retval = -EINVAL;
301         }
302 
303 done:
304         if (retval == 0) {
305                 dev->dev.power.power_state = PMSG_SUSPEND;
306 
307 #ifdef CONFIG_PPC_PMAC
308                 /* Disable ASIC clocks for USB */
309                 if (machine_is(powermac)) {
310                         struct device_node      *of_node;
311 
312                         of_node = pci_device_to_OF_node(dev);
313                         if (of_node)
314                                 pmac_call_feature(PMAC_FTR_USB_ENABLE,
315                                                         of_node, 0, 0);
316                 }
317 #endif
318         }
319 
320         return retval;
321 }
322 EXPORT_SYMBOL_GPL(usb_hcd_pci_suspend);
323 
324 /**
325  * usb_hcd_pci_resume - power management resume of a PCI-based HCD
326  * @dev: USB Host Controller being resumed
327  *
328  * Store this function in the HCD's struct pci_driver as resume().
329  */
330 int usb_hcd_pci_resume(struct pci_dev *dev)
331 {
332         struct usb_hcd          *hcd;
333         int                     retval;
334 
335         hcd = pci_get_drvdata(dev);
336         if (hcd->state != HC_STATE_SUSPENDED) {
337                 dev_dbg(hcd->self.controller,
338                                 "can't resume, not suspended!\n");
339                 return 0;
340         }
341 
342 #ifdef CONFIG_PPC_PMAC
343         /* Reenable ASIC clocks for USB */
344         if (machine_is(powermac)) {
345                 struct device_node *of_node;
346 
347                 of_node = pci_device_to_OF_node(dev);
348                 if (of_node)
349                         pmac_call_feature(PMAC_FTR_USB_ENABLE,
350                                                 of_node, 0, 1);
351         }
352 #endif
353 
354         /* NOTE:  chip docs cover clean "real suspend" cases (what Linux
355          * calls "standby", "suspend to RAM", and so on).  There are also
356          * dirty cases when swsusp fakes a suspend in "shutdown" mode.
357          */
358         if (dev->current_state != PCI_D0) {
359 #ifdef  DEBUG
360                 int     pci_pm;
361                 u16     pmcr;
362 
363                 pci_pm = pci_find_capability(dev, PCI_CAP_ID_PM);
364                 pci_read_config_word(dev, pci_pm + PCI_PM_CTRL, &pmcr);
365                 pmcr &= PCI_PM_CTRL_STATE_MASK;
366                 if (pmcr) {
367                         /* Clean case:  power to USB and to HC registers was
368                          * maintained; remote wakeup is easy.
369                          */
370                         dev_dbg(hcd->self.controller, "resume from PCI D%d\n",
371                                         pmcr);
372                 } else {
373                         /* Clean:  HC lost Vcc power, D0 uninitialized
374                          *   + Vaux may have preserved port and transceiver
375                          *     state ... for remote wakeup from D3cold
376                          *   + or not; HCD must reinit + re-enumerate
377                          *
378                          * Dirty: D0 semi-initialized cases with swsusp
379                          *   + after BIOS init
380                          *   + after Linux init (HCD statically linked)
381                          */
382                         dev_dbg(hcd->self.controller,
383                                 "PCI D0, from previous PCI D%d\n",
384                                 dev->current_state);
385                 }
386 #endif
387                 /* yes, ignore these results too... */
388                 (void) pci_enable_wake(dev, dev->current_state, 0);
389                 (void) pci_enable_wake(dev, PCI_D3cold, 0);
390         } else {
391                 /* Same basic cases: clean (powered/not), dirty */
392                 dev_dbg(hcd->self.controller, "PCI legacy resume\n");
393         }
394 
395         /* NOTE:  the PCI API itself is asymmetric here.  We don't need to
396          * pci_set_power_state(PCI_D0) since that's part of re-enabling;
397          * but that won't re-enable bus mastering.  Yet pci_disable_device()
398          * explicitly disables bus mastering...
399          */
400         retval = pci_enable_device(dev);
401         if (retval < 0) {
402                 dev_err(hcd->self.controller,
403                         "can't re-enable after resume, %d!\n", retval);
404                 return retval;
405         }
406         pci_set_master(dev);
407         pci_restore_state(dev);
408 
409         dev->dev.power.power_state = PMSG_ON;
410 
411         clear_bit(HCD_FLAG_SAW_IRQ, &hcd->flags);
412 
413         if (hcd->driver->resume) {
414                 retval = hcd->driver->resume(hcd);
415                 if (retval) {
416                         dev_err(hcd->self.controller,
417                                 "PCI post-resume error %d!\n", retval);
418                         usb_hc_died(hcd);
419                 }
420         }
421 
422         return retval;
423 }
424 EXPORT_SYMBOL_GPL(usb_hcd_pci_resume);
425 
426 #endif  /* CONFIG_PM */
427 
428 /**
429  * usb_hcd_pci_shutdown - shutdown host controller
430  * @dev: USB Host Controller being shutdown
431  */
432 void usb_hcd_pci_shutdown(struct pci_dev *dev)
433 {
434         struct usb_hcd          *hcd;
435 
436         hcd = pci_get_drvdata(dev);
437         if (!hcd)
438                 return;
439 
440         if (hcd->driver->shutdown)
441                 hcd->driver->shutdown(hcd);
442 }
443 EXPORT_SYMBOL_GPL(usb_hcd_pci_shutdown);
444 
445 
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