Xen: consolidate and simplify struct xenbus_driver instantiation
[linux-2.6.git] / drivers / pci / xen-pcifront.c
1 /*
2  * Xen PCI Frontend.
3  *
4  *   Author: Ryan Wilson <hap9@epoch.ncsc.mil>
5  */
6 #include <linux/module.h>
7 #include <linux/init.h>
8 #include <linux/mm.h>
9 #include <xen/xenbus.h>
10 #include <xen/events.h>
11 #include <xen/grant_table.h>
12 #include <xen/page.h>
13 #include <linux/spinlock.h>
14 #include <linux/pci.h>
15 #include <linux/msi.h>
16 #include <xen/interface/io/pciif.h>
17 #include <asm/xen/pci.h>
18 #include <linux/interrupt.h>
19 #include <linux/atomic.h>
20 #include <linux/workqueue.h>
21 #include <linux/bitops.h>
22 #include <linux/time.h>
23
24 #define INVALID_GRANT_REF (0)
25 #define INVALID_EVTCHN    (-1)
26
27 struct pci_bus_entry {
28         struct list_head list;
29         struct pci_bus *bus;
30 };
31
32 #define _PDEVB_op_active                (0)
33 #define PDEVB_op_active                 (1 << (_PDEVB_op_active))
34
35 struct pcifront_device {
36         struct xenbus_device *xdev;
37         struct list_head root_buses;
38
39         int evtchn;
40         int gnt_ref;
41
42         int irq;
43
44         /* Lock this when doing any operations in sh_info */
45         spinlock_t sh_info_lock;
46         struct xen_pci_sharedinfo *sh_info;
47         struct work_struct op_work;
48         unsigned long flags;
49
50 };
51
52 struct pcifront_sd {
53         int domain;
54         struct pcifront_device *pdev;
55 };
56
57 static inline struct pcifront_device *
58 pcifront_get_pdev(struct pcifront_sd *sd)
59 {
60         return sd->pdev;
61 }
62
63 static inline void pcifront_init_sd(struct pcifront_sd *sd,
64                                     unsigned int domain, unsigned int bus,
65                                     struct pcifront_device *pdev)
66 {
67         sd->domain = domain;
68         sd->pdev = pdev;
69 }
70
71 static DEFINE_SPINLOCK(pcifront_dev_lock);
72 static struct pcifront_device *pcifront_dev;
73
74 static int verbose_request;
75 module_param(verbose_request, int, 0644);
76
77 static int errno_to_pcibios_err(int errno)
78 {
79         switch (errno) {
80         case XEN_PCI_ERR_success:
81                 return PCIBIOS_SUCCESSFUL;
82
83         case XEN_PCI_ERR_dev_not_found:
84                 return PCIBIOS_DEVICE_NOT_FOUND;
85
86         case XEN_PCI_ERR_invalid_offset:
87         case XEN_PCI_ERR_op_failed:
88                 return PCIBIOS_BAD_REGISTER_NUMBER;
89
90         case XEN_PCI_ERR_not_implemented:
91                 return PCIBIOS_FUNC_NOT_SUPPORTED;
92
93         case XEN_PCI_ERR_access_denied:
94                 return PCIBIOS_SET_FAILED;
95         }
96         return errno;
97 }
98
99 static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
100 {
101         if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
102                 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
103                 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
104                 schedule_work(&pdev->op_work);
105         }
106 }
107
108 static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
109 {
110         int err = 0;
111         struct xen_pci_op *active_op = &pdev->sh_info->op;
112         unsigned long irq_flags;
113         evtchn_port_t port = pdev->evtchn;
114         unsigned irq = pdev->irq;
115         s64 ns, ns_timeout;
116         struct timeval tv;
117
118         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
119
120         memcpy(active_op, op, sizeof(struct xen_pci_op));
121
122         /* Go */
123         wmb();
124         set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
125         notify_remote_via_evtchn(port);
126
127         /*
128          * We set a poll timeout of 3 seconds but give up on return after
129          * 2 seconds. It is better to time out too late rather than too early
130          * (in the latter case we end up continually re-executing poll() with a
131          * timeout in the past). 1s difference gives plenty of slack for error.
132          */
133         do_gettimeofday(&tv);
134         ns_timeout = timeval_to_ns(&tv) + 2 * (s64)NSEC_PER_SEC;
135
136         xen_clear_irq_pending(irq);
137
138         while (test_bit(_XEN_PCIF_active,
139                         (unsigned long *)&pdev->sh_info->flags)) {
140                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
141                 xen_clear_irq_pending(irq);
142                 do_gettimeofday(&tv);
143                 ns = timeval_to_ns(&tv);
144                 if (ns > ns_timeout) {
145                         dev_err(&pdev->xdev->dev,
146                                 "pciback not responding!!!\n");
147                         clear_bit(_XEN_PCIF_active,
148                                   (unsigned long *)&pdev->sh_info->flags);
149                         err = XEN_PCI_ERR_dev_not_found;
150                         goto out;
151                 }
152         }
153
154         /*
155         * We might lose backend service request since we
156         * reuse same evtchn with pci_conf backend response. So re-schedule
157         * aer pcifront service.
158         */
159         if (test_bit(_XEN_PCIB_active,
160                         (unsigned long *)&pdev->sh_info->flags)) {
161                 dev_err(&pdev->xdev->dev,
162                         "schedule aer pcifront service\n");
163                 schedule_pcifront_aer_op(pdev);
164         }
165
166         memcpy(op, active_op, sizeof(struct xen_pci_op));
167
168         err = op->err;
169 out:
170         spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
171         return err;
172 }
173
174 /* Access to this function is spinlocked in drivers/pci/access.c */
175 static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
176                              int where, int size, u32 *val)
177 {
178         int err = 0;
179         struct xen_pci_op op = {
180                 .cmd    = XEN_PCI_OP_conf_read,
181                 .domain = pci_domain_nr(bus),
182                 .bus    = bus->number,
183                 .devfn  = devfn,
184                 .offset = where,
185                 .size   = size,
186         };
187         struct pcifront_sd *sd = bus->sysdata;
188         struct pcifront_device *pdev = pcifront_get_pdev(sd);
189
190         if (verbose_request)
191                 dev_info(&pdev->xdev->dev,
192                          "read dev=%04x:%02x:%02x.%01x - offset %x size %d\n",
193                          pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
194                          PCI_FUNC(devfn), where, size);
195
196         err = do_pci_op(pdev, &op);
197
198         if (likely(!err)) {
199                 if (verbose_request)
200                         dev_info(&pdev->xdev->dev, "read got back value %x\n",
201                                  op.value);
202
203                 *val = op.value;
204         } else if (err == -ENODEV) {
205                 /* No device here, pretend that it just returned 0 */
206                 err = 0;
207                 *val = 0;
208         }
209
210         return errno_to_pcibios_err(err);
211 }
212
213 /* Access to this function is spinlocked in drivers/pci/access.c */
214 static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
215                               int where, int size, u32 val)
216 {
217         struct xen_pci_op op = {
218                 .cmd    = XEN_PCI_OP_conf_write,
219                 .domain = pci_domain_nr(bus),
220                 .bus    = bus->number,
221                 .devfn  = devfn,
222                 .offset = where,
223                 .size   = size,
224                 .value  = val,
225         };
226         struct pcifront_sd *sd = bus->sysdata;
227         struct pcifront_device *pdev = pcifront_get_pdev(sd);
228
229         if (verbose_request)
230                 dev_info(&pdev->xdev->dev,
231                          "write dev=%04x:%02x:%02x.%01x - "
232                          "offset %x size %d val %x\n",
233                          pci_domain_nr(bus), bus->number,
234                          PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
235
236         return errno_to_pcibios_err(do_pci_op(pdev, &op));
237 }
238
239 struct pci_ops pcifront_bus_ops = {
240         .read = pcifront_bus_read,
241         .write = pcifront_bus_write,
242 };
243
244 #ifdef CONFIG_PCI_MSI
245 static int pci_frontend_enable_msix(struct pci_dev *dev,
246                                     int vector[], int nvec)
247 {
248         int err;
249         int i;
250         struct xen_pci_op op = {
251                 .cmd    = XEN_PCI_OP_enable_msix,
252                 .domain = pci_domain_nr(dev->bus),
253                 .bus = dev->bus->number,
254                 .devfn = dev->devfn,
255                 .value = nvec,
256         };
257         struct pcifront_sd *sd = dev->bus->sysdata;
258         struct pcifront_device *pdev = pcifront_get_pdev(sd);
259         struct msi_desc *entry;
260
261         if (nvec > SH_INFO_MAX_VEC) {
262                 dev_err(&dev->dev, "too much vector for pci frontend: %x."
263                                    " Increase SH_INFO_MAX_VEC.\n", nvec);
264                 return -EINVAL;
265         }
266
267         i = 0;
268         list_for_each_entry(entry, &dev->msi_list, list) {
269                 op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
270                 /* Vector is useless at this point. */
271                 op.msix_entries[i].vector = -1;
272                 i++;
273         }
274
275         err = do_pci_op(pdev, &op);
276
277         if (likely(!err)) {
278                 if (likely(!op.value)) {
279                         /* we get the result */
280                         for (i = 0; i < nvec; i++) {
281                                 if (op.msix_entries[i].vector <= 0) {
282                                         dev_warn(&dev->dev, "MSI-X entry %d is invalid: %d!\n",
283                                                 i, op.msix_entries[i].vector);
284                                         err = -EINVAL;
285                                         vector[i] = -1;
286                                         continue;
287                                 }
288                                 vector[i] = op.msix_entries[i].vector;
289                         }
290                 } else {
291                         printk(KERN_DEBUG "enable msix get value %x\n",
292                                 op.value);
293                 }
294         } else {
295                 dev_err(&dev->dev, "enable msix get err %x\n", err);
296         }
297         return err;
298 }
299
300 static void pci_frontend_disable_msix(struct pci_dev *dev)
301 {
302         int err;
303         struct xen_pci_op op = {
304                 .cmd    = XEN_PCI_OP_disable_msix,
305                 .domain = pci_domain_nr(dev->bus),
306                 .bus = dev->bus->number,
307                 .devfn = dev->devfn,
308         };
309         struct pcifront_sd *sd = dev->bus->sysdata;
310         struct pcifront_device *pdev = pcifront_get_pdev(sd);
311
312         err = do_pci_op(pdev, &op);
313
314         /* What should do for error ? */
315         if (err)
316                 dev_err(&dev->dev, "pci_disable_msix get err %x\n", err);
317 }
318
319 static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
320 {
321         int err;
322         struct xen_pci_op op = {
323                 .cmd    = XEN_PCI_OP_enable_msi,
324                 .domain = pci_domain_nr(dev->bus),
325                 .bus = dev->bus->number,
326                 .devfn = dev->devfn,
327         };
328         struct pcifront_sd *sd = dev->bus->sysdata;
329         struct pcifront_device *pdev = pcifront_get_pdev(sd);
330
331         err = do_pci_op(pdev, &op);
332         if (likely(!err)) {
333                 vector[0] = op.value;
334                 if (op.value <= 0) {
335                         dev_warn(&dev->dev, "MSI entry is invalid: %d!\n",
336                                 op.value);
337                         err = -EINVAL;
338                         vector[0] = -1;
339                 }
340         } else {
341                 dev_err(&dev->dev, "pci frontend enable msi failed for dev "
342                                     "%x:%x\n", op.bus, op.devfn);
343                 err = -EINVAL;
344         }
345         return err;
346 }
347
348 static void pci_frontend_disable_msi(struct pci_dev *dev)
349 {
350         int err;
351         struct xen_pci_op op = {
352                 .cmd    = XEN_PCI_OP_disable_msi,
353                 .domain = pci_domain_nr(dev->bus),
354                 .bus = dev->bus->number,
355                 .devfn = dev->devfn,
356         };
357         struct pcifront_sd *sd = dev->bus->sysdata;
358         struct pcifront_device *pdev = pcifront_get_pdev(sd);
359
360         err = do_pci_op(pdev, &op);
361         if (err == XEN_PCI_ERR_dev_not_found) {
362                 /* XXX No response from backend, what shall we do? */
363                 printk(KERN_DEBUG "get no response from backend for disable MSI\n");
364                 return;
365         }
366         if (err)
367                 /* how can pciback notify us fail? */
368                 printk(KERN_DEBUG "get fake response frombackend\n");
369 }
370
371 static struct xen_pci_frontend_ops pci_frontend_ops = {
372         .enable_msi = pci_frontend_enable_msi,
373         .disable_msi = pci_frontend_disable_msi,
374         .enable_msix = pci_frontend_enable_msix,
375         .disable_msix = pci_frontend_disable_msix,
376 };
377
378 static void pci_frontend_registrar(int enable)
379 {
380         if (enable)
381                 xen_pci_frontend = &pci_frontend_ops;
382         else
383                 xen_pci_frontend = NULL;
384 };
385 #else
386 static inline void pci_frontend_registrar(int enable) { };
387 #endif /* CONFIG_PCI_MSI */
388
389 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
390 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
391 {
392         struct pcifront_device *pdev = data;
393         int i;
394         struct resource *r;
395
396         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
397                 r = &dev->resource[i];
398
399                 if (!r->parent && r->start && r->flags) {
400                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
401                                 pci_name(dev), i);
402                         if (pci_claim_resource(dev, i)) {
403                                 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
404                                         "Device offline. Try using e820_host=1 in the guest config.\n",
405                                         pci_name(dev), i);
406                         }
407                 }
408         }
409
410         return 0;
411 }
412
413 static int __devinit pcifront_scan_bus(struct pcifront_device *pdev,
414                                 unsigned int domain, unsigned int bus,
415                                 struct pci_bus *b)
416 {
417         struct pci_dev *d;
418         unsigned int devfn;
419
420         /* Scan the bus for functions and add.
421          * We omit handling of PCI bridge attachment because pciback prevents
422          * bridges from being exported.
423          */
424         for (devfn = 0; devfn < 0x100; devfn++) {
425                 d = pci_get_slot(b, devfn);
426                 if (d) {
427                         /* Device is already known. */
428                         pci_dev_put(d);
429                         continue;
430                 }
431
432                 d = pci_scan_single_device(b, devfn);
433                 if (d)
434                         dev_info(&pdev->xdev->dev, "New device on "
435                                  "%04x:%02x:%02x.%02x found.\n", domain, bus,
436                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
437         }
438
439         return 0;
440 }
441
442 static int __devinit pcifront_scan_root(struct pcifront_device *pdev,
443                                  unsigned int domain, unsigned int bus)
444 {
445         struct pci_bus *b;
446         struct pcifront_sd *sd = NULL;
447         struct pci_bus_entry *bus_entry = NULL;
448         int err = 0;
449
450 #ifndef CONFIG_PCI_DOMAINS
451         if (domain != 0) {
452                 dev_err(&pdev->xdev->dev,
453                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
454                 dev_err(&pdev->xdev->dev,
455                         "Please compile with CONFIG_PCI_DOMAINS\n");
456                 err = -EINVAL;
457                 goto err_out;
458         }
459 #endif
460
461         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
462                  domain, bus);
463
464         bus_entry = kmalloc(sizeof(*bus_entry), GFP_KERNEL);
465         sd = kmalloc(sizeof(*sd), GFP_KERNEL);
466         if (!bus_entry || !sd) {
467                 err = -ENOMEM;
468                 goto err_out;
469         }
470         pcifront_init_sd(sd, domain, bus, pdev);
471
472         b = pci_scan_bus_parented(&pdev->xdev->dev, bus,
473                                   &pcifront_bus_ops, sd);
474         if (!b) {
475                 dev_err(&pdev->xdev->dev,
476                         "Error creating PCI Frontend Bus!\n");
477                 err = -ENOMEM;
478                 goto err_out;
479         }
480
481         bus_entry->bus = b;
482
483         list_add(&bus_entry->list, &pdev->root_buses);
484
485         /* pci_scan_bus_parented skips devices which do not have a have
486         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
487         err = pcifront_scan_bus(pdev, domain, bus, b);
488
489         /* Claim resources before going "live" with our devices */
490         pci_walk_bus(b, pcifront_claim_resource, pdev);
491
492         /* Create SysFS and notify udev of the devices. Aka: "going live" */
493         pci_bus_add_devices(b);
494
495         return err;
496
497 err_out:
498         kfree(bus_entry);
499         kfree(sd);
500
501         return err;
502 }
503
504 static int __devinit pcifront_rescan_root(struct pcifront_device *pdev,
505                                    unsigned int domain, unsigned int bus)
506 {
507         int err;
508         struct pci_bus *b;
509
510 #ifndef CONFIG_PCI_DOMAINS
511         if (domain != 0) {
512                 dev_err(&pdev->xdev->dev,
513                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
514                 dev_err(&pdev->xdev->dev,
515                         "Please compile with CONFIG_PCI_DOMAINS\n");
516                 return -EINVAL;
517         }
518 #endif
519
520         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
521                  domain, bus);
522
523         b = pci_find_bus(domain, bus);
524         if (!b)
525                 /* If the bus is unknown, create it. */
526                 return pcifront_scan_root(pdev, domain, bus);
527
528         err = pcifront_scan_bus(pdev, domain, bus, b);
529
530         /* Claim resources before going "live" with our devices */
531         pci_walk_bus(b, pcifront_claim_resource, pdev);
532
533         /* Create SysFS and notify udev of the devices. Aka: "going live" */
534         pci_bus_add_devices(b);
535
536         return err;
537 }
538
539 static void free_root_bus_devs(struct pci_bus *bus)
540 {
541         struct pci_dev *dev;
542
543         while (!list_empty(&bus->devices)) {
544                 dev = container_of(bus->devices.next, struct pci_dev,
545                                    bus_list);
546                 dev_dbg(&dev->dev, "removing device\n");
547                 pci_remove_bus_device(dev);
548         }
549 }
550
551 static void pcifront_free_roots(struct pcifront_device *pdev)
552 {
553         struct pci_bus_entry *bus_entry, *t;
554
555         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
556
557         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
558                 list_del(&bus_entry->list);
559
560                 free_root_bus_devs(bus_entry->bus);
561
562                 kfree(bus_entry->bus->sysdata);
563
564                 device_unregister(bus_entry->bus->bridge);
565                 pci_remove_bus(bus_entry->bus);
566
567                 kfree(bus_entry);
568         }
569 }
570
571 static pci_ers_result_t pcifront_common_process(int cmd,
572                                                 struct pcifront_device *pdev,
573                                                 pci_channel_state_t state)
574 {
575         pci_ers_result_t result;
576         struct pci_driver *pdrv;
577         int bus = pdev->sh_info->aer_op.bus;
578         int devfn = pdev->sh_info->aer_op.devfn;
579         struct pci_dev *pcidev;
580         int flag = 0;
581
582         dev_dbg(&pdev->xdev->dev,
583                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
584                 cmd, bus, devfn);
585         result = PCI_ERS_RESULT_NONE;
586
587         pcidev = pci_get_bus_and_slot(bus, devfn);
588         if (!pcidev || !pcidev->driver) {
589                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
590                 if (pcidev)
591                         pci_dev_put(pcidev);
592                 return result;
593         }
594         pdrv = pcidev->driver;
595
596         if (get_driver(&pdrv->driver)) {
597                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
598                         dev_dbg(&pcidev->dev,
599                                 "trying to call AER service\n");
600                         if (pcidev) {
601                                 flag = 1;
602                                 switch (cmd) {
603                                 case XEN_PCI_OP_aer_detected:
604                                         result = pdrv->err_handler->
605                                                  error_detected(pcidev, state);
606                                         break;
607                                 case XEN_PCI_OP_aer_mmio:
608                                         result = pdrv->err_handler->
609                                                  mmio_enabled(pcidev);
610                                         break;
611                                 case XEN_PCI_OP_aer_slotreset:
612                                         result = pdrv->err_handler->
613                                                  slot_reset(pcidev);
614                                         break;
615                                 case XEN_PCI_OP_aer_resume:
616                                         pdrv->err_handler->resume(pcidev);
617                                         break;
618                                 default:
619                                         dev_err(&pdev->xdev->dev,
620                                                 "bad request in aer recovery "
621                                                 "operation!\n");
622
623                                 }
624                         }
625                 }
626                 put_driver(&pdrv->driver);
627         }
628         if (!flag)
629                 result = PCI_ERS_RESULT_NONE;
630
631         return result;
632 }
633
634
635 static void pcifront_do_aer(struct work_struct *data)
636 {
637         struct pcifront_device *pdev =
638                 container_of(data, struct pcifront_device, op_work);
639         int cmd = pdev->sh_info->aer_op.cmd;
640         pci_channel_state_t state =
641                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
642
643         /*If a pci_conf op is in progress,
644                 we have to wait until it is done before service aer op*/
645         dev_dbg(&pdev->xdev->dev,
646                 "pcifront service aer bus %x devfn %x\n",
647                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
648
649         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
650
651         /* Post the operation to the guest. */
652         wmb();
653         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
654         notify_remote_via_evtchn(pdev->evtchn);
655
656         /*in case of we lost an aer request in four lines time_window*/
657         smp_mb__before_clear_bit();
658         clear_bit(_PDEVB_op_active, &pdev->flags);
659         smp_mb__after_clear_bit();
660
661         schedule_pcifront_aer_op(pdev);
662
663 }
664
665 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
666 {
667         struct pcifront_device *pdev = dev;
668         schedule_pcifront_aer_op(pdev);
669         return IRQ_HANDLED;
670 }
671 static int pcifront_connect(struct pcifront_device *pdev)
672 {
673         int err = 0;
674
675         spin_lock(&pcifront_dev_lock);
676
677         if (!pcifront_dev) {
678                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
679                 pcifront_dev = pdev;
680         } else {
681                 dev_err(&pdev->xdev->dev, "PCI frontend already installed!\n");
682                 err = -EEXIST;
683         }
684
685         spin_unlock(&pcifront_dev_lock);
686
687         return err;
688 }
689
690 static void pcifront_disconnect(struct pcifront_device *pdev)
691 {
692         spin_lock(&pcifront_dev_lock);
693
694         if (pdev == pcifront_dev) {
695                 dev_info(&pdev->xdev->dev,
696                          "Disconnecting PCI Frontend Buses\n");
697                 pcifront_dev = NULL;
698         }
699
700         spin_unlock(&pcifront_dev_lock);
701 }
702 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
703 {
704         struct pcifront_device *pdev;
705
706         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
707         if (pdev == NULL)
708                 goto out;
709
710         pdev->sh_info =
711             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
712         if (pdev->sh_info == NULL) {
713                 kfree(pdev);
714                 pdev = NULL;
715                 goto out;
716         }
717         pdev->sh_info->flags = 0;
718
719         /*Flag for registering PV AER handler*/
720         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
721
722         dev_set_drvdata(&xdev->dev, pdev);
723         pdev->xdev = xdev;
724
725         INIT_LIST_HEAD(&pdev->root_buses);
726
727         spin_lock_init(&pdev->sh_info_lock);
728
729         pdev->evtchn = INVALID_EVTCHN;
730         pdev->gnt_ref = INVALID_GRANT_REF;
731         pdev->irq = -1;
732
733         INIT_WORK(&pdev->op_work, pcifront_do_aer);
734
735         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
736                 pdev, pdev->sh_info);
737 out:
738         return pdev;
739 }
740
741 static void free_pdev(struct pcifront_device *pdev)
742 {
743         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
744
745         pcifront_free_roots(pdev);
746
747         cancel_work_sync(&pdev->op_work);
748
749         if (pdev->irq >= 0)
750                 unbind_from_irqhandler(pdev->irq, pdev);
751
752         if (pdev->evtchn != INVALID_EVTCHN)
753                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
754
755         if (pdev->gnt_ref != INVALID_GRANT_REF)
756                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
757                                           (unsigned long)pdev->sh_info);
758         else
759                 free_page((unsigned long)pdev->sh_info);
760
761         dev_set_drvdata(&pdev->xdev->dev, NULL);
762
763         kfree(pdev);
764 }
765
766 static int pcifront_publish_info(struct pcifront_device *pdev)
767 {
768         int err = 0;
769         struct xenbus_transaction trans;
770
771         err = xenbus_grant_ring(pdev->xdev, virt_to_mfn(pdev->sh_info));
772         if (err < 0)
773                 goto out;
774
775         pdev->gnt_ref = err;
776
777         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
778         if (err)
779                 goto out;
780
781         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
782                 0, "pcifront", pdev);
783
784         if (err < 0)
785                 return err;
786
787         pdev->irq = err;
788
789 do_publish:
790         err = xenbus_transaction_start(&trans);
791         if (err) {
792                 xenbus_dev_fatal(pdev->xdev, err,
793                                  "Error writing configuration for backend "
794                                  "(start transaction)");
795                 goto out;
796         }
797
798         err = xenbus_printf(trans, pdev->xdev->nodename,
799                             "pci-op-ref", "%u", pdev->gnt_ref);
800         if (!err)
801                 err = xenbus_printf(trans, pdev->xdev->nodename,
802                                     "event-channel", "%u", pdev->evtchn);
803         if (!err)
804                 err = xenbus_printf(trans, pdev->xdev->nodename,
805                                     "magic", XEN_PCI_MAGIC);
806
807         if (err) {
808                 xenbus_transaction_end(trans, 1);
809                 xenbus_dev_fatal(pdev->xdev, err,
810                                  "Error writing configuration for backend");
811                 goto out;
812         } else {
813                 err = xenbus_transaction_end(trans, 0);
814                 if (err == -EAGAIN)
815                         goto do_publish;
816                 else if (err) {
817                         xenbus_dev_fatal(pdev->xdev, err,
818                                          "Error completing transaction "
819                                          "for backend");
820                         goto out;
821                 }
822         }
823
824         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
825
826         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
827
828 out:
829         return err;
830 }
831
832 static int __devinit pcifront_try_connect(struct pcifront_device *pdev)
833 {
834         int err = -EFAULT;
835         int i, num_roots, len;
836         char str[64];
837         unsigned int domain, bus;
838
839
840         /* Only connect once */
841         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
842             XenbusStateInitialised)
843                 goto out;
844
845         err = pcifront_connect(pdev);
846         if (err) {
847                 xenbus_dev_fatal(pdev->xdev, err,
848                                  "Error connecting PCI Frontend");
849                 goto out;
850         }
851
852         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
853                            "root_num", "%d", &num_roots);
854         if (err == -ENOENT) {
855                 xenbus_dev_error(pdev->xdev, err,
856                                  "No PCI Roots found, trying 0000:00");
857                 err = pcifront_scan_root(pdev, 0, 0);
858                 num_roots = 0;
859         } else if (err != 1) {
860                 if (err == 0)
861                         err = -EINVAL;
862                 xenbus_dev_fatal(pdev->xdev, err,
863                                  "Error reading number of PCI roots");
864                 goto out;
865         }
866
867         for (i = 0; i < num_roots; i++) {
868                 len = snprintf(str, sizeof(str), "root-%d", i);
869                 if (unlikely(len >= (sizeof(str) - 1))) {
870                         err = -ENOMEM;
871                         goto out;
872                 }
873
874                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
875                                    "%x:%x", &domain, &bus);
876                 if (err != 2) {
877                         if (err >= 0)
878                                 err = -EINVAL;
879                         xenbus_dev_fatal(pdev->xdev, err,
880                                          "Error reading PCI root %d", i);
881                         goto out;
882                 }
883
884                 err = pcifront_scan_root(pdev, domain, bus);
885                 if (err) {
886                         xenbus_dev_fatal(pdev->xdev, err,
887                                          "Error scanning PCI root %04x:%02x",
888                                          domain, bus);
889                         goto out;
890                 }
891         }
892
893         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
894
895 out:
896         return err;
897 }
898
899 static int pcifront_try_disconnect(struct pcifront_device *pdev)
900 {
901         int err = 0;
902         enum xenbus_state prev_state;
903
904
905         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
906
907         if (prev_state >= XenbusStateClosing)
908                 goto out;
909
910         if (prev_state == XenbusStateConnected) {
911                 pcifront_free_roots(pdev);
912                 pcifront_disconnect(pdev);
913         }
914
915         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
916
917 out:
918
919         return err;
920 }
921
922 static int __devinit pcifront_attach_devices(struct pcifront_device *pdev)
923 {
924         int err = -EFAULT;
925         int i, num_roots, len;
926         unsigned int domain, bus;
927         char str[64];
928
929         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
930             XenbusStateReconfiguring)
931                 goto out;
932
933         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
934                            "root_num", "%d", &num_roots);
935         if (err == -ENOENT) {
936                 xenbus_dev_error(pdev->xdev, err,
937                                  "No PCI Roots found, trying 0000:00");
938                 err = pcifront_rescan_root(pdev, 0, 0);
939                 num_roots = 0;
940         } else if (err != 1) {
941                 if (err == 0)
942                         err = -EINVAL;
943                 xenbus_dev_fatal(pdev->xdev, err,
944                                  "Error reading number of PCI roots");
945                 goto out;
946         }
947
948         for (i = 0; i < num_roots; i++) {
949                 len = snprintf(str, sizeof(str), "root-%d", i);
950                 if (unlikely(len >= (sizeof(str) - 1))) {
951                         err = -ENOMEM;
952                         goto out;
953                 }
954
955                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
956                                    "%x:%x", &domain, &bus);
957                 if (err != 2) {
958                         if (err >= 0)
959                                 err = -EINVAL;
960                         xenbus_dev_fatal(pdev->xdev, err,
961                                          "Error reading PCI root %d", i);
962                         goto out;
963                 }
964
965                 err = pcifront_rescan_root(pdev, domain, bus);
966                 if (err) {
967                         xenbus_dev_fatal(pdev->xdev, err,
968                                          "Error scanning PCI root %04x:%02x",
969                                          domain, bus);
970                         goto out;
971                 }
972         }
973
974         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
975
976 out:
977         return err;
978 }
979
980 static int pcifront_detach_devices(struct pcifront_device *pdev)
981 {
982         int err = 0;
983         int i, num_devs;
984         unsigned int domain, bus, slot, func;
985         struct pci_bus *pci_bus;
986         struct pci_dev *pci_dev;
987         char str[64];
988
989         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
990             XenbusStateConnected)
991                 goto out;
992
993         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
994                            &num_devs);
995         if (err != 1) {
996                 if (err >= 0)
997                         err = -EINVAL;
998                 xenbus_dev_fatal(pdev->xdev, err,
999                                  "Error reading number of PCI devices");
1000                 goto out;
1001         }
1002
1003         /* Find devices being detached and remove them. */
1004         for (i = 0; i < num_devs; i++) {
1005                 int l, state;
1006                 l = snprintf(str, sizeof(str), "state-%d", i);
1007                 if (unlikely(l >= (sizeof(str) - 1))) {
1008                         err = -ENOMEM;
1009                         goto out;
1010                 }
1011                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str, "%d",
1012                                    &state);
1013                 if (err != 1)
1014                         state = XenbusStateUnknown;
1015
1016                 if (state != XenbusStateClosing)
1017                         continue;
1018
1019                 /* Remove device. */
1020                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1021                 if (unlikely(l >= (sizeof(str) - 1))) {
1022                         err = -ENOMEM;
1023                         goto out;
1024                 }
1025                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1026                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1027                 if (err != 4) {
1028                         if (err >= 0)
1029                                 err = -EINVAL;
1030                         xenbus_dev_fatal(pdev->xdev, err,
1031                                          "Error reading PCI device %d", i);
1032                         goto out;
1033                 }
1034
1035                 pci_bus = pci_find_bus(domain, bus);
1036                 if (!pci_bus) {
1037                         dev_dbg(&pdev->xdev->dev, "Cannot get bus %04x:%02x\n",
1038                                 domain, bus);
1039                         continue;
1040                 }
1041                 pci_dev = pci_get_slot(pci_bus, PCI_DEVFN(slot, func));
1042                 if (!pci_dev) {
1043                         dev_dbg(&pdev->xdev->dev,
1044                                 "Cannot get PCI device %04x:%02x:%02x.%02x\n",
1045                                 domain, bus, slot, func);
1046                         continue;
1047                 }
1048                 pci_remove_bus_device(pci_dev);
1049                 pci_dev_put(pci_dev);
1050
1051                 dev_dbg(&pdev->xdev->dev,
1052                         "PCI device %04x:%02x:%02x.%02x removed.\n",
1053                         domain, bus, slot, func);
1054         }
1055
1056         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1057
1058 out:
1059         return err;
1060 }
1061
1062 static void __init_refok pcifront_backend_changed(struct xenbus_device *xdev,
1063                                                   enum xenbus_state be_state)
1064 {
1065         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1066
1067         switch (be_state) {
1068         case XenbusStateUnknown:
1069         case XenbusStateInitialising:
1070         case XenbusStateInitWait:
1071         case XenbusStateInitialised:
1072         case XenbusStateClosed:
1073                 break;
1074
1075         case XenbusStateConnected:
1076                 pcifront_try_connect(pdev);
1077                 break;
1078
1079         case XenbusStateClosing:
1080                 dev_warn(&xdev->dev, "backend going away!\n");
1081                 pcifront_try_disconnect(pdev);
1082                 break;
1083
1084         case XenbusStateReconfiguring:
1085                 pcifront_detach_devices(pdev);
1086                 break;
1087
1088         case XenbusStateReconfigured:
1089                 pcifront_attach_devices(pdev);
1090                 break;
1091         }
1092 }
1093
1094 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1095                                  const struct xenbus_device_id *id)
1096 {
1097         int err = 0;
1098         struct pcifront_device *pdev = alloc_pdev(xdev);
1099
1100         if (pdev == NULL) {
1101                 err = -ENOMEM;
1102                 xenbus_dev_fatal(xdev, err,
1103                                  "Error allocating pcifront_device struct");
1104                 goto out;
1105         }
1106
1107         err = pcifront_publish_info(pdev);
1108         if (err)
1109                 free_pdev(pdev);
1110
1111 out:
1112         return err;
1113 }
1114
1115 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1116 {
1117         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1118         if (pdev)
1119                 free_pdev(pdev);
1120
1121         return 0;
1122 }
1123
1124 static const struct xenbus_device_id xenpci_ids[] = {
1125         {"pci"},
1126         {""},
1127 };
1128
1129 static DEFINE_XENBUS_DRIVER(xenpci, "pcifront",
1130         .probe                  = pcifront_xenbus_probe,
1131         .remove                 = pcifront_xenbus_remove,
1132         .otherend_changed       = pcifront_backend_changed,
1133 );
1134
1135 static int __init pcifront_init(void)
1136 {
1137         if (!xen_pv_domain() || xen_initial_domain())
1138                 return -ENODEV;
1139
1140         pci_frontend_registrar(1 /* enable */);
1141
1142         return xenbus_register_frontend(&xenpci_driver);
1143 }
1144
1145 static void __exit pcifront_cleanup(void)
1146 {
1147         xenbus_unregister_driver(&xenpci_driver);
1148         pci_frontend_registrar(0 /* disable */);
1149 }
1150 module_init(pcifront_init);
1151 module_exit(pcifront_cleanup);
1152
1153 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1154 MODULE_LICENSE("GPL");
1155 MODULE_ALIAS("xen:pci");