Merge branch 'clk-qcom-sdm845' into clk-next
[linux-2.6-microblaze.git] / drivers / pci / xen-pcifront.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Xen PCI Frontend
4  *
5  * Author: Ryan Wilson <hap9@epoch.ncsc.mil>
6  */
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/mm.h>
10 #include <xen/xenbus.h>
11 #include <xen/events.h>
12 #include <xen/grant_table.h>
13 #include <xen/page.h>
14 #include <linux/spinlock.h>
15 #include <linux/pci.h>
16 #include <linux/msi.h>
17 #include <xen/interface/io/pciif.h>
18 #include <asm/xen/pci.h>
19 #include <linux/interrupt.h>
20 #include <linux/atomic.h>
21 #include <linux/workqueue.h>
22 #include <linux/bitops.h>
23 #include <linux/time.h>
24 #include <linux/ktime.h>
25 #include <xen/platform_pci.h>
26
27 #include <asm/xen/swiotlb-xen.h>
28 #define INVALID_GRANT_REF (0)
29 #define INVALID_EVTCHN    (-1)
30
31 struct pci_bus_entry {
32         struct list_head list;
33         struct pci_bus *bus;
34 };
35
36 #define _PDEVB_op_active                (0)
37 #define PDEVB_op_active                 (1 << (_PDEVB_op_active))
38
39 struct pcifront_device {
40         struct xenbus_device *xdev;
41         struct list_head root_buses;
42
43         int evtchn;
44         int gnt_ref;
45
46         int irq;
47
48         /* Lock this when doing any operations in sh_info */
49         spinlock_t sh_info_lock;
50         struct xen_pci_sharedinfo *sh_info;
51         struct work_struct op_work;
52         unsigned long flags;
53
54 };
55
56 struct pcifront_sd {
57         struct pci_sysdata sd;
58         struct pcifront_device *pdev;
59 };
60
61 static inline struct pcifront_device *
62 pcifront_get_pdev(struct pcifront_sd *sd)
63 {
64         return sd->pdev;
65 }
66
67 static inline void pcifront_init_sd(struct pcifront_sd *sd,
68                                     unsigned int domain, unsigned int bus,
69                                     struct pcifront_device *pdev)
70 {
71         /* Because we do not expose that information via XenBus. */
72         sd->sd.node = first_online_node;
73         sd->sd.domain = domain;
74         sd->pdev = pdev;
75 }
76
77 static DEFINE_SPINLOCK(pcifront_dev_lock);
78 static struct pcifront_device *pcifront_dev;
79
80 static int verbose_request;
81 module_param(verbose_request, int, 0644);
82
83 static int errno_to_pcibios_err(int errno)
84 {
85         switch (errno) {
86         case XEN_PCI_ERR_success:
87                 return PCIBIOS_SUCCESSFUL;
88
89         case XEN_PCI_ERR_dev_not_found:
90                 return PCIBIOS_DEVICE_NOT_FOUND;
91
92         case XEN_PCI_ERR_invalid_offset:
93         case XEN_PCI_ERR_op_failed:
94                 return PCIBIOS_BAD_REGISTER_NUMBER;
95
96         case XEN_PCI_ERR_not_implemented:
97                 return PCIBIOS_FUNC_NOT_SUPPORTED;
98
99         case XEN_PCI_ERR_access_denied:
100                 return PCIBIOS_SET_FAILED;
101         }
102         return errno;
103 }
104
105 static inline void schedule_pcifront_aer_op(struct pcifront_device *pdev)
106 {
107         if (test_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags)
108                 && !test_and_set_bit(_PDEVB_op_active, &pdev->flags)) {
109                 dev_dbg(&pdev->xdev->dev, "schedule aer frontend job\n");
110                 schedule_work(&pdev->op_work);
111         }
112 }
113
114 static int do_pci_op(struct pcifront_device *pdev, struct xen_pci_op *op)
115 {
116         int err = 0;
117         struct xen_pci_op *active_op = &pdev->sh_info->op;
118         unsigned long irq_flags;
119         evtchn_port_t port = pdev->evtchn;
120         unsigned irq = pdev->irq;
121         s64 ns, ns_timeout;
122
123         spin_lock_irqsave(&pdev->sh_info_lock, irq_flags);
124
125         memcpy(active_op, op, sizeof(struct xen_pci_op));
126
127         /* Go */
128         wmb();
129         set_bit(_XEN_PCIF_active, (unsigned long *)&pdev->sh_info->flags);
130         notify_remote_via_evtchn(port);
131
132         /*
133          * We set a poll timeout of 3 seconds but give up on return after
134          * 2 seconds. It is better to time out too late rather than too early
135          * (in the latter case we end up continually re-executing poll() with a
136          * timeout in the past). 1s difference gives plenty of slack for error.
137          */
138         ns_timeout = ktime_get_ns() + 2 * (s64)NSEC_PER_SEC;
139
140         xen_clear_irq_pending(irq);
141
142         while (test_bit(_XEN_PCIF_active,
143                         (unsigned long *)&pdev->sh_info->flags)) {
144                 xen_poll_irq_timeout(irq, jiffies + 3*HZ);
145                 xen_clear_irq_pending(irq);
146                 ns = ktime_get_ns();
147                 if (ns > ns_timeout) {
148                         dev_err(&pdev->xdev->dev,
149                                 "pciback not responding!!!\n");
150                         clear_bit(_XEN_PCIF_active,
151                                   (unsigned long *)&pdev->sh_info->flags);
152                         err = XEN_PCI_ERR_dev_not_found;
153                         goto out;
154                 }
155         }
156
157         /*
158         * We might lose backend service request since we
159         * reuse same evtchn with pci_conf backend response. So re-schedule
160         * aer pcifront service.
161         */
162         if (test_bit(_XEN_PCIB_active,
163                         (unsigned long *)&pdev->sh_info->flags)) {
164                 dev_err(&pdev->xdev->dev,
165                         "schedule aer pcifront service\n");
166                 schedule_pcifront_aer_op(pdev);
167         }
168
169         memcpy(op, active_op, sizeof(struct xen_pci_op));
170
171         err = op->err;
172 out:
173         spin_unlock_irqrestore(&pdev->sh_info_lock, irq_flags);
174         return err;
175 }
176
177 /* Access to this function is spinlocked in drivers/pci/access.c */
178 static int pcifront_bus_read(struct pci_bus *bus, unsigned int devfn,
179                              int where, int size, u32 *val)
180 {
181         int err = 0;
182         struct xen_pci_op op = {
183                 .cmd    = XEN_PCI_OP_conf_read,
184                 .domain = pci_domain_nr(bus),
185                 .bus    = bus->number,
186                 .devfn  = devfn,
187                 .offset = where,
188                 .size   = size,
189         };
190         struct pcifront_sd *sd = bus->sysdata;
191         struct pcifront_device *pdev = pcifront_get_pdev(sd);
192
193         if (verbose_request)
194                 dev_info(&pdev->xdev->dev,
195                          "read dev=%04x:%02x:%02x.%d - offset %x size %d\n",
196                          pci_domain_nr(bus), bus->number, PCI_SLOT(devfn),
197                          PCI_FUNC(devfn), where, size);
198
199         err = do_pci_op(pdev, &op);
200
201         if (likely(!err)) {
202                 if (verbose_request)
203                         dev_info(&pdev->xdev->dev, "read got back value %x\n",
204                                  op.value);
205
206                 *val = op.value;
207         } else if (err == -ENODEV) {
208                 /* No device here, pretend that it just returned 0 */
209                 err = 0;
210                 *val = 0;
211         }
212
213         return errno_to_pcibios_err(err);
214 }
215
216 /* Access to this function is spinlocked in drivers/pci/access.c */
217 static int pcifront_bus_write(struct pci_bus *bus, unsigned int devfn,
218                               int where, int size, u32 val)
219 {
220         struct xen_pci_op op = {
221                 .cmd    = XEN_PCI_OP_conf_write,
222                 .domain = pci_domain_nr(bus),
223                 .bus    = bus->number,
224                 .devfn  = devfn,
225                 .offset = where,
226                 .size   = size,
227                 .value  = val,
228         };
229         struct pcifront_sd *sd = bus->sysdata;
230         struct pcifront_device *pdev = pcifront_get_pdev(sd);
231
232         if (verbose_request)
233                 dev_info(&pdev->xdev->dev,
234                          "write dev=%04x:%02x:%02x.%d - "
235                          "offset %x size %d val %x\n",
236                          pci_domain_nr(bus), bus->number,
237                          PCI_SLOT(devfn), PCI_FUNC(devfn), where, size, val);
238
239         return errno_to_pcibios_err(do_pci_op(pdev, &op));
240 }
241
242 static struct pci_ops pcifront_bus_ops = {
243         .read = pcifront_bus_read,
244         .write = pcifront_bus_write,
245 };
246
247 #ifdef CONFIG_PCI_MSI
248 static int pci_frontend_enable_msix(struct pci_dev *dev,
249                                     int vector[], int nvec)
250 {
251         int err;
252         int i;
253         struct xen_pci_op op = {
254                 .cmd    = XEN_PCI_OP_enable_msix,
255                 .domain = pci_domain_nr(dev->bus),
256                 .bus = dev->bus->number,
257                 .devfn = dev->devfn,
258                 .value = nvec,
259         };
260         struct pcifront_sd *sd = dev->bus->sysdata;
261         struct pcifront_device *pdev = pcifront_get_pdev(sd);
262         struct msi_desc *entry;
263
264         if (nvec > SH_INFO_MAX_VEC) {
265                 pci_err(dev, "too many vectors (0x%x) for PCI frontend:"
266                                    " Increase SH_INFO_MAX_VEC\n", nvec);
267                 return -EINVAL;
268         }
269
270         i = 0;
271         for_each_pci_msi_entry(entry, dev) {
272                 op.msix_entries[i].entry = entry->msi_attrib.entry_nr;
273                 /* Vector is useless at this point. */
274                 op.msix_entries[i].vector = -1;
275                 i++;
276         }
277
278         err = do_pci_op(pdev, &op);
279
280         if (likely(!err)) {
281                 if (likely(!op.value)) {
282                         /* we get the result */
283                         for (i = 0; i < nvec; i++) {
284                                 if (op.msix_entries[i].vector <= 0) {
285                                         pci_warn(dev, "MSI-X entry %d is invalid: %d!\n",
286                                                 i, op.msix_entries[i].vector);
287                                         err = -EINVAL;
288                                         vector[i] = -1;
289                                         continue;
290                                 }
291                                 vector[i] = op.msix_entries[i].vector;
292                         }
293                 } else {
294                         printk(KERN_DEBUG "enable msix get value %x\n",
295                                 op.value);
296                         err = op.value;
297                 }
298         } else {
299                 pci_err(dev, "enable msix get err %x\n", err);
300         }
301         return err;
302 }
303
304 static void pci_frontend_disable_msix(struct pci_dev *dev)
305 {
306         int err;
307         struct xen_pci_op op = {
308                 .cmd    = XEN_PCI_OP_disable_msix,
309                 .domain = pci_domain_nr(dev->bus),
310                 .bus = dev->bus->number,
311                 .devfn = dev->devfn,
312         };
313         struct pcifront_sd *sd = dev->bus->sysdata;
314         struct pcifront_device *pdev = pcifront_get_pdev(sd);
315
316         err = do_pci_op(pdev, &op);
317
318         /* What should do for error ? */
319         if (err)
320                 pci_err(dev, "pci_disable_msix get err %x\n", err);
321 }
322
323 static int pci_frontend_enable_msi(struct pci_dev *dev, int vector[])
324 {
325         int err;
326         struct xen_pci_op op = {
327                 .cmd    = XEN_PCI_OP_enable_msi,
328                 .domain = pci_domain_nr(dev->bus),
329                 .bus = dev->bus->number,
330                 .devfn = dev->devfn,
331         };
332         struct pcifront_sd *sd = dev->bus->sysdata;
333         struct pcifront_device *pdev = pcifront_get_pdev(sd);
334
335         err = do_pci_op(pdev, &op);
336         if (likely(!err)) {
337                 vector[0] = op.value;
338                 if (op.value <= 0) {
339                         pci_warn(dev, "MSI entry is invalid: %d!\n",
340                                 op.value);
341                         err = -EINVAL;
342                         vector[0] = -1;
343                 }
344         } else {
345                 pci_err(dev, "pci frontend enable msi failed for dev "
346                                     "%x:%x\n", op.bus, op.devfn);
347                 err = -EINVAL;
348         }
349         return err;
350 }
351
352 static void pci_frontend_disable_msi(struct pci_dev *dev)
353 {
354         int err;
355         struct xen_pci_op op = {
356                 .cmd    = XEN_PCI_OP_disable_msi,
357                 .domain = pci_domain_nr(dev->bus),
358                 .bus = dev->bus->number,
359                 .devfn = dev->devfn,
360         };
361         struct pcifront_sd *sd = dev->bus->sysdata;
362         struct pcifront_device *pdev = pcifront_get_pdev(sd);
363
364         err = do_pci_op(pdev, &op);
365         if (err == XEN_PCI_ERR_dev_not_found) {
366                 /* XXX No response from backend, what shall we do? */
367                 printk(KERN_DEBUG "get no response from backend for disable MSI\n");
368                 return;
369         }
370         if (err)
371                 /* how can pciback notify us fail? */
372                 printk(KERN_DEBUG "get fake response frombackend\n");
373 }
374
375 static struct xen_pci_frontend_ops pci_frontend_ops = {
376         .enable_msi = pci_frontend_enable_msi,
377         .disable_msi = pci_frontend_disable_msi,
378         .enable_msix = pci_frontend_enable_msix,
379         .disable_msix = pci_frontend_disable_msix,
380 };
381
382 static void pci_frontend_registrar(int enable)
383 {
384         if (enable)
385                 xen_pci_frontend = &pci_frontend_ops;
386         else
387                 xen_pci_frontend = NULL;
388 };
389 #else
390 static inline void pci_frontend_registrar(int enable) { };
391 #endif /* CONFIG_PCI_MSI */
392
393 /* Claim resources for the PCI frontend as-is, backend won't allow changes */
394 static int pcifront_claim_resource(struct pci_dev *dev, void *data)
395 {
396         struct pcifront_device *pdev = data;
397         int i;
398         struct resource *r;
399
400         for (i = 0; i < PCI_NUM_RESOURCES; i++) {
401                 r = &dev->resource[i];
402
403                 if (!r->parent && r->start && r->flags) {
404                         dev_info(&pdev->xdev->dev, "claiming resource %s/%d\n",
405                                 pci_name(dev), i);
406                         if (pci_claim_resource(dev, i)) {
407                                 dev_err(&pdev->xdev->dev, "Could not claim resource %s/%d! "
408                                         "Device offline. Try using e820_host=1 in the guest config.\n",
409                                         pci_name(dev), i);
410                         }
411                 }
412         }
413
414         return 0;
415 }
416
417 static int pcifront_scan_bus(struct pcifront_device *pdev,
418                                 unsigned int domain, unsigned int bus,
419                                 struct pci_bus *b)
420 {
421         struct pci_dev *d;
422         unsigned int devfn;
423
424         /* Scan the bus for functions and add.
425          * We omit handling of PCI bridge attachment because pciback prevents
426          * bridges from being exported.
427          */
428         for (devfn = 0; devfn < 0x100; devfn++) {
429                 d = pci_get_slot(b, devfn);
430                 if (d) {
431                         /* Device is already known. */
432                         pci_dev_put(d);
433                         continue;
434                 }
435
436                 d = pci_scan_single_device(b, devfn);
437                 if (d)
438                         dev_info(&pdev->xdev->dev, "New device on "
439                                  "%04x:%02x:%02x.%d found.\n", domain, bus,
440                                  PCI_SLOT(devfn), PCI_FUNC(devfn));
441         }
442
443         return 0;
444 }
445
446 static int pcifront_scan_root(struct pcifront_device *pdev,
447                                  unsigned int domain, unsigned int bus)
448 {
449         struct pci_bus *b;
450         LIST_HEAD(resources);
451         struct pcifront_sd *sd = NULL;
452         struct pci_bus_entry *bus_entry = NULL;
453         int err = 0;
454         static struct resource busn_res = {
455                 .start = 0,
456                 .end = 255,
457                 .flags = IORESOURCE_BUS,
458         };
459
460 #ifndef CONFIG_PCI_DOMAINS
461         if (domain != 0) {
462                 dev_err(&pdev->xdev->dev,
463                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
464                 dev_err(&pdev->xdev->dev,
465                         "Please compile with CONFIG_PCI_DOMAINS\n");
466                 err = -EINVAL;
467                 goto err_out;
468         }
469 #endif
470
471         dev_info(&pdev->xdev->dev, "Creating PCI Frontend Bus %04x:%02x\n",
472                  domain, bus);
473
474         bus_entry = kzalloc(sizeof(*bus_entry), GFP_KERNEL);
475         sd = kzalloc(sizeof(*sd), GFP_KERNEL);
476         if (!bus_entry || !sd) {
477                 err = -ENOMEM;
478                 goto err_out;
479         }
480         pci_add_resource(&resources, &ioport_resource);
481         pci_add_resource(&resources, &iomem_resource);
482         pci_add_resource(&resources, &busn_res);
483         pcifront_init_sd(sd, domain, bus, pdev);
484
485         pci_lock_rescan_remove();
486
487         b = pci_scan_root_bus(&pdev->xdev->dev, bus,
488                                   &pcifront_bus_ops, sd, &resources);
489         if (!b) {
490                 dev_err(&pdev->xdev->dev,
491                         "Error creating PCI Frontend Bus!\n");
492                 err = -ENOMEM;
493                 pci_unlock_rescan_remove();
494                 pci_free_resource_list(&resources);
495                 goto err_out;
496         }
497
498         bus_entry->bus = b;
499
500         list_add(&bus_entry->list, &pdev->root_buses);
501
502         /* pci_scan_root_bus skips devices which do not have a
503         * devfn==0. The pcifront_scan_bus enumerates all devfn. */
504         err = pcifront_scan_bus(pdev, domain, bus, b);
505
506         /* Claim resources before going "live" with our devices */
507         pci_walk_bus(b, pcifront_claim_resource, pdev);
508
509         /* Create SysFS and notify udev of the devices. Aka: "going live" */
510         pci_bus_add_devices(b);
511
512         pci_unlock_rescan_remove();
513         return err;
514
515 err_out:
516         kfree(bus_entry);
517         kfree(sd);
518
519         return err;
520 }
521
522 static int pcifront_rescan_root(struct pcifront_device *pdev,
523                                    unsigned int domain, unsigned int bus)
524 {
525         int err;
526         struct pci_bus *b;
527
528 #ifndef CONFIG_PCI_DOMAINS
529         if (domain != 0) {
530                 dev_err(&pdev->xdev->dev,
531                         "PCI Root in non-zero PCI Domain! domain=%d\n", domain);
532                 dev_err(&pdev->xdev->dev,
533                         "Please compile with CONFIG_PCI_DOMAINS\n");
534                 return -EINVAL;
535         }
536 #endif
537
538         dev_info(&pdev->xdev->dev, "Rescanning PCI Frontend Bus %04x:%02x\n",
539                  domain, bus);
540
541         b = pci_find_bus(domain, bus);
542         if (!b)
543                 /* If the bus is unknown, create it. */
544                 return pcifront_scan_root(pdev, domain, bus);
545
546         err = pcifront_scan_bus(pdev, domain, bus, b);
547
548         /* Claim resources before going "live" with our devices */
549         pci_walk_bus(b, pcifront_claim_resource, pdev);
550
551         /* Create SysFS and notify udev of the devices. Aka: "going live" */
552         pci_bus_add_devices(b);
553
554         return err;
555 }
556
557 static void free_root_bus_devs(struct pci_bus *bus)
558 {
559         struct pci_dev *dev;
560
561         while (!list_empty(&bus->devices)) {
562                 dev = container_of(bus->devices.next, struct pci_dev,
563                                    bus_list);
564                 pci_dbg(dev, "removing device\n");
565                 pci_stop_and_remove_bus_device(dev);
566         }
567 }
568
569 static void pcifront_free_roots(struct pcifront_device *pdev)
570 {
571         struct pci_bus_entry *bus_entry, *t;
572
573         dev_dbg(&pdev->xdev->dev, "cleaning up root buses\n");
574
575         pci_lock_rescan_remove();
576         list_for_each_entry_safe(bus_entry, t, &pdev->root_buses, list) {
577                 list_del(&bus_entry->list);
578
579                 free_root_bus_devs(bus_entry->bus);
580
581                 kfree(bus_entry->bus->sysdata);
582
583                 device_unregister(bus_entry->bus->bridge);
584                 pci_remove_bus(bus_entry->bus);
585
586                 kfree(bus_entry);
587         }
588         pci_unlock_rescan_remove();
589 }
590
591 static pci_ers_result_t pcifront_common_process(int cmd,
592                                                 struct pcifront_device *pdev,
593                                                 pci_channel_state_t state)
594 {
595         pci_ers_result_t result;
596         struct pci_driver *pdrv;
597         int bus = pdev->sh_info->aer_op.bus;
598         int devfn = pdev->sh_info->aer_op.devfn;
599         int domain = pdev->sh_info->aer_op.domain;
600         struct pci_dev *pcidev;
601         int flag = 0;
602
603         dev_dbg(&pdev->xdev->dev,
604                 "pcifront AER process: cmd %x (bus:%x, devfn%x)",
605                 cmd, bus, devfn);
606         result = PCI_ERS_RESULT_NONE;
607
608         pcidev = pci_get_domain_bus_and_slot(domain, bus, devfn);
609         if (!pcidev || !pcidev->driver) {
610                 dev_err(&pdev->xdev->dev, "device or AER driver is NULL\n");
611                 pci_dev_put(pcidev);
612                 return result;
613         }
614         pdrv = pcidev->driver;
615
616         if (pdrv) {
617                 if (pdrv->err_handler && pdrv->err_handler->error_detected) {
618                         pci_dbg(pcidev, "trying to call AER service\n");
619                         if (pcidev) {
620                                 flag = 1;
621                                 switch (cmd) {
622                                 case XEN_PCI_OP_aer_detected:
623                                         result = pdrv->err_handler->
624                                                  error_detected(pcidev, state);
625                                         break;
626                                 case XEN_PCI_OP_aer_mmio:
627                                         result = pdrv->err_handler->
628                                                  mmio_enabled(pcidev);
629                                         break;
630                                 case XEN_PCI_OP_aer_slotreset:
631                                         result = pdrv->err_handler->
632                                                  slot_reset(pcidev);
633                                         break;
634                                 case XEN_PCI_OP_aer_resume:
635                                         pdrv->err_handler->resume(pcidev);
636                                         break;
637                                 default:
638                                         dev_err(&pdev->xdev->dev,
639                                                 "bad request in aer recovery "
640                                                 "operation!\n");
641
642                                 }
643                         }
644                 }
645         }
646         if (!flag)
647                 result = PCI_ERS_RESULT_NONE;
648
649         return result;
650 }
651
652
653 static void pcifront_do_aer(struct work_struct *data)
654 {
655         struct pcifront_device *pdev =
656                 container_of(data, struct pcifront_device, op_work);
657         int cmd = pdev->sh_info->aer_op.cmd;
658         pci_channel_state_t state =
659                 (pci_channel_state_t)pdev->sh_info->aer_op.err;
660
661         /*If a pci_conf op is in progress,
662                 we have to wait until it is done before service aer op*/
663         dev_dbg(&pdev->xdev->dev,
664                 "pcifront service aer bus %x devfn %x\n",
665                 pdev->sh_info->aer_op.bus, pdev->sh_info->aer_op.devfn);
666
667         pdev->sh_info->aer_op.err = pcifront_common_process(cmd, pdev, state);
668
669         /* Post the operation to the guest. */
670         wmb();
671         clear_bit(_XEN_PCIB_active, (unsigned long *)&pdev->sh_info->flags);
672         notify_remote_via_evtchn(pdev->evtchn);
673
674         /*in case of we lost an aer request in four lines time_window*/
675         smp_mb__before_atomic();
676         clear_bit(_PDEVB_op_active, &pdev->flags);
677         smp_mb__after_atomic();
678
679         schedule_pcifront_aer_op(pdev);
680
681 }
682
683 static irqreturn_t pcifront_handler_aer(int irq, void *dev)
684 {
685         struct pcifront_device *pdev = dev;
686         schedule_pcifront_aer_op(pdev);
687         return IRQ_HANDLED;
688 }
689 static int pcifront_connect_and_init_dma(struct pcifront_device *pdev)
690 {
691         int err = 0;
692
693         spin_lock(&pcifront_dev_lock);
694
695         if (!pcifront_dev) {
696                 dev_info(&pdev->xdev->dev, "Installing PCI frontend\n");
697                 pcifront_dev = pdev;
698         } else
699                 err = -EEXIST;
700
701         spin_unlock(&pcifront_dev_lock);
702
703         if (!err && !swiotlb_nr_tbl()) {
704                 err = pci_xen_swiotlb_init_late();
705                 if (err)
706                         dev_err(&pdev->xdev->dev, "Could not setup SWIOTLB!\n");
707         }
708         return err;
709 }
710
711 static void pcifront_disconnect(struct pcifront_device *pdev)
712 {
713         spin_lock(&pcifront_dev_lock);
714
715         if (pdev == pcifront_dev) {
716                 dev_info(&pdev->xdev->dev,
717                          "Disconnecting PCI Frontend Buses\n");
718                 pcifront_dev = NULL;
719         }
720
721         spin_unlock(&pcifront_dev_lock);
722 }
723 static struct pcifront_device *alloc_pdev(struct xenbus_device *xdev)
724 {
725         struct pcifront_device *pdev;
726
727         pdev = kzalloc(sizeof(struct pcifront_device), GFP_KERNEL);
728         if (pdev == NULL)
729                 goto out;
730
731         pdev->sh_info =
732             (struct xen_pci_sharedinfo *)__get_free_page(GFP_KERNEL);
733         if (pdev->sh_info == NULL) {
734                 kfree(pdev);
735                 pdev = NULL;
736                 goto out;
737         }
738         pdev->sh_info->flags = 0;
739
740         /*Flag for registering PV AER handler*/
741         set_bit(_XEN_PCIB_AERHANDLER, (void *)&pdev->sh_info->flags);
742
743         dev_set_drvdata(&xdev->dev, pdev);
744         pdev->xdev = xdev;
745
746         INIT_LIST_HEAD(&pdev->root_buses);
747
748         spin_lock_init(&pdev->sh_info_lock);
749
750         pdev->evtchn = INVALID_EVTCHN;
751         pdev->gnt_ref = INVALID_GRANT_REF;
752         pdev->irq = -1;
753
754         INIT_WORK(&pdev->op_work, pcifront_do_aer);
755
756         dev_dbg(&xdev->dev, "Allocated pdev @ 0x%p pdev->sh_info @ 0x%p\n",
757                 pdev, pdev->sh_info);
758 out:
759         return pdev;
760 }
761
762 static void free_pdev(struct pcifront_device *pdev)
763 {
764         dev_dbg(&pdev->xdev->dev, "freeing pdev @ 0x%p\n", pdev);
765
766         pcifront_free_roots(pdev);
767
768         cancel_work_sync(&pdev->op_work);
769
770         if (pdev->irq >= 0)
771                 unbind_from_irqhandler(pdev->irq, pdev);
772
773         if (pdev->evtchn != INVALID_EVTCHN)
774                 xenbus_free_evtchn(pdev->xdev, pdev->evtchn);
775
776         if (pdev->gnt_ref != INVALID_GRANT_REF)
777                 gnttab_end_foreign_access(pdev->gnt_ref, 0 /* r/w page */,
778                                           (unsigned long)pdev->sh_info);
779         else
780                 free_page((unsigned long)pdev->sh_info);
781
782         dev_set_drvdata(&pdev->xdev->dev, NULL);
783
784         kfree(pdev);
785 }
786
787 static int pcifront_publish_info(struct pcifront_device *pdev)
788 {
789         int err = 0;
790         struct xenbus_transaction trans;
791         grant_ref_t gref;
792
793         err = xenbus_grant_ring(pdev->xdev, pdev->sh_info, 1, &gref);
794         if (err < 0)
795                 goto out;
796
797         pdev->gnt_ref = gref;
798
799         err = xenbus_alloc_evtchn(pdev->xdev, &pdev->evtchn);
800         if (err)
801                 goto out;
802
803         err = bind_evtchn_to_irqhandler(pdev->evtchn, pcifront_handler_aer,
804                 0, "pcifront", pdev);
805
806         if (err < 0)
807                 return err;
808
809         pdev->irq = err;
810
811 do_publish:
812         err = xenbus_transaction_start(&trans);
813         if (err) {
814                 xenbus_dev_fatal(pdev->xdev, err,
815                                  "Error writing configuration for backend "
816                                  "(start transaction)");
817                 goto out;
818         }
819
820         err = xenbus_printf(trans, pdev->xdev->nodename,
821                             "pci-op-ref", "%u", pdev->gnt_ref);
822         if (!err)
823                 err = xenbus_printf(trans, pdev->xdev->nodename,
824                                     "event-channel", "%u", pdev->evtchn);
825         if (!err)
826                 err = xenbus_printf(trans, pdev->xdev->nodename,
827                                     "magic", XEN_PCI_MAGIC);
828
829         if (err) {
830                 xenbus_transaction_end(trans, 1);
831                 xenbus_dev_fatal(pdev->xdev, err,
832                                  "Error writing configuration for backend");
833                 goto out;
834         } else {
835                 err = xenbus_transaction_end(trans, 0);
836                 if (err == -EAGAIN)
837                         goto do_publish;
838                 else if (err) {
839                         xenbus_dev_fatal(pdev->xdev, err,
840                                          "Error completing transaction "
841                                          "for backend");
842                         goto out;
843                 }
844         }
845
846         xenbus_switch_state(pdev->xdev, XenbusStateInitialised);
847
848         dev_dbg(&pdev->xdev->dev, "publishing successful!\n");
849
850 out:
851         return err;
852 }
853
854 static int pcifront_try_connect(struct pcifront_device *pdev)
855 {
856         int err = -EFAULT;
857         int i, num_roots, len;
858         char str[64];
859         unsigned int domain, bus;
860
861
862         /* Only connect once */
863         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
864             XenbusStateInitialised)
865                 goto out;
866
867         err = pcifront_connect_and_init_dma(pdev);
868         if (err && err != -EEXIST) {
869                 xenbus_dev_fatal(pdev->xdev, err,
870                                  "Error setting up PCI Frontend");
871                 goto out;
872         }
873
874         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
875                            "root_num", "%d", &num_roots);
876         if (err == -ENOENT) {
877                 xenbus_dev_error(pdev->xdev, err,
878                                  "No PCI Roots found, trying 0000:00");
879                 err = pcifront_scan_root(pdev, 0, 0);
880                 if (err) {
881                         xenbus_dev_fatal(pdev->xdev, err,
882                                          "Error scanning PCI root 0000:00");
883                         goto out;
884                 }
885                 num_roots = 0;
886         } else if (err != 1) {
887                 if (err == 0)
888                         err = -EINVAL;
889                 xenbus_dev_fatal(pdev->xdev, err,
890                                  "Error reading number of PCI roots");
891                 goto out;
892         }
893
894         for (i = 0; i < num_roots; i++) {
895                 len = snprintf(str, sizeof(str), "root-%d", i);
896                 if (unlikely(len >= (sizeof(str) - 1))) {
897                         err = -ENOMEM;
898                         goto out;
899                 }
900
901                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
902                                    "%x:%x", &domain, &bus);
903                 if (err != 2) {
904                         if (err >= 0)
905                                 err = -EINVAL;
906                         xenbus_dev_fatal(pdev->xdev, err,
907                                          "Error reading PCI root %d", i);
908                         goto out;
909                 }
910
911                 err = pcifront_scan_root(pdev, domain, bus);
912                 if (err) {
913                         xenbus_dev_fatal(pdev->xdev, err,
914                                          "Error scanning PCI root %04x:%02x",
915                                          domain, bus);
916                         goto out;
917                 }
918         }
919
920         err = xenbus_switch_state(pdev->xdev, XenbusStateConnected);
921
922 out:
923         return err;
924 }
925
926 static int pcifront_try_disconnect(struct pcifront_device *pdev)
927 {
928         int err = 0;
929         enum xenbus_state prev_state;
930
931
932         prev_state = xenbus_read_driver_state(pdev->xdev->nodename);
933
934         if (prev_state >= XenbusStateClosing)
935                 goto out;
936
937         if (prev_state == XenbusStateConnected) {
938                 pcifront_free_roots(pdev);
939                 pcifront_disconnect(pdev);
940         }
941
942         err = xenbus_switch_state(pdev->xdev, XenbusStateClosed);
943
944 out:
945
946         return err;
947 }
948
949 static int pcifront_attach_devices(struct pcifront_device *pdev)
950 {
951         int err = -EFAULT;
952         int i, num_roots, len;
953         unsigned int domain, bus;
954         char str[64];
955
956         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
957             XenbusStateReconfiguring)
958                 goto out;
959
960         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend,
961                            "root_num", "%d", &num_roots);
962         if (err == -ENOENT) {
963                 xenbus_dev_error(pdev->xdev, err,
964                                  "No PCI Roots found, trying 0000:00");
965                 err = pcifront_rescan_root(pdev, 0, 0);
966                 if (err) {
967                         xenbus_dev_fatal(pdev->xdev, err,
968                                          "Error scanning PCI root 0000:00");
969                         goto out;
970                 }
971                 num_roots = 0;
972         } else if (err != 1) {
973                 if (err == 0)
974                         err = -EINVAL;
975                 xenbus_dev_fatal(pdev->xdev, err,
976                                  "Error reading number of PCI roots");
977                 goto out;
978         }
979
980         for (i = 0; i < num_roots; i++) {
981                 len = snprintf(str, sizeof(str), "root-%d", i);
982                 if (unlikely(len >= (sizeof(str) - 1))) {
983                         err = -ENOMEM;
984                         goto out;
985                 }
986
987                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
988                                    "%x:%x", &domain, &bus);
989                 if (err != 2) {
990                         if (err >= 0)
991                                 err = -EINVAL;
992                         xenbus_dev_fatal(pdev->xdev, err,
993                                          "Error reading PCI root %d", i);
994                         goto out;
995                 }
996
997                 err = pcifront_rescan_root(pdev, domain, bus);
998                 if (err) {
999                         xenbus_dev_fatal(pdev->xdev, err,
1000                                          "Error scanning PCI root %04x:%02x",
1001                                          domain, bus);
1002                         goto out;
1003                 }
1004         }
1005
1006         xenbus_switch_state(pdev->xdev, XenbusStateConnected);
1007
1008 out:
1009         return err;
1010 }
1011
1012 static int pcifront_detach_devices(struct pcifront_device *pdev)
1013 {
1014         int err = 0;
1015         int i, num_devs;
1016         unsigned int domain, bus, slot, func;
1017         struct pci_dev *pci_dev;
1018         char str[64];
1019
1020         if (xenbus_read_driver_state(pdev->xdev->nodename) !=
1021             XenbusStateConnected)
1022                 goto out;
1023
1024         err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, "num_devs", "%d",
1025                            &num_devs);
1026         if (err != 1) {
1027                 if (err >= 0)
1028                         err = -EINVAL;
1029                 xenbus_dev_fatal(pdev->xdev, err,
1030                                  "Error reading number of PCI devices");
1031                 goto out;
1032         }
1033
1034         /* Find devices being detached and remove them. */
1035         for (i = 0; i < num_devs; i++) {
1036                 int l, state;
1037                 l = snprintf(str, sizeof(str), "state-%d", i);
1038                 if (unlikely(l >= (sizeof(str) - 1))) {
1039                         err = -ENOMEM;
1040                         goto out;
1041                 }
1042                 state = xenbus_read_unsigned(pdev->xdev->otherend, str,
1043                                              XenbusStateUnknown);
1044
1045                 if (state != XenbusStateClosing)
1046                         continue;
1047
1048                 /* Remove device. */
1049                 l = snprintf(str, sizeof(str), "vdev-%d", i);
1050                 if (unlikely(l >= (sizeof(str) - 1))) {
1051                         err = -ENOMEM;
1052                         goto out;
1053                 }
1054                 err = xenbus_scanf(XBT_NIL, pdev->xdev->otherend, str,
1055                                    "%x:%x:%x.%x", &domain, &bus, &slot, &func);
1056                 if (err != 4) {
1057                         if (err >= 0)
1058                                 err = -EINVAL;
1059                         xenbus_dev_fatal(pdev->xdev, err,
1060                                          "Error reading PCI device %d", i);
1061                         goto out;
1062                 }
1063
1064                 pci_dev = pci_get_domain_bus_and_slot(domain, bus,
1065                                 PCI_DEVFN(slot, func));
1066                 if (!pci_dev) {
1067                         dev_dbg(&pdev->xdev->dev,
1068                                 "Cannot get PCI device %04x:%02x:%02x.%d\n",
1069                                 domain, bus, slot, func);
1070                         continue;
1071                 }
1072                 pci_lock_rescan_remove();
1073                 pci_stop_and_remove_bus_device(pci_dev);
1074                 pci_dev_put(pci_dev);
1075                 pci_unlock_rescan_remove();
1076
1077                 dev_dbg(&pdev->xdev->dev,
1078                         "PCI device %04x:%02x:%02x.%d removed.\n",
1079                         domain, bus, slot, func);
1080         }
1081
1082         err = xenbus_switch_state(pdev->xdev, XenbusStateReconfiguring);
1083
1084 out:
1085         return err;
1086 }
1087
1088 static void __ref pcifront_backend_changed(struct xenbus_device *xdev,
1089                                                   enum xenbus_state be_state)
1090 {
1091         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1092
1093         switch (be_state) {
1094         case XenbusStateUnknown:
1095         case XenbusStateInitialising:
1096         case XenbusStateInitWait:
1097         case XenbusStateInitialised:
1098                 break;
1099
1100         case XenbusStateConnected:
1101                 pcifront_try_connect(pdev);
1102                 break;
1103
1104         case XenbusStateClosed:
1105                 if (xdev->state == XenbusStateClosed)
1106                         break;
1107                 /* Missed the backend's CLOSING state -- fallthrough */
1108         case XenbusStateClosing:
1109                 dev_warn(&xdev->dev, "backend going away!\n");
1110                 pcifront_try_disconnect(pdev);
1111                 break;
1112
1113         case XenbusStateReconfiguring:
1114                 pcifront_detach_devices(pdev);
1115                 break;
1116
1117         case XenbusStateReconfigured:
1118                 pcifront_attach_devices(pdev);
1119                 break;
1120         }
1121 }
1122
1123 static int pcifront_xenbus_probe(struct xenbus_device *xdev,
1124                                  const struct xenbus_device_id *id)
1125 {
1126         int err = 0;
1127         struct pcifront_device *pdev = alloc_pdev(xdev);
1128
1129         if (pdev == NULL) {
1130                 err = -ENOMEM;
1131                 xenbus_dev_fatal(xdev, err,
1132                                  "Error allocating pcifront_device struct");
1133                 goto out;
1134         }
1135
1136         err = pcifront_publish_info(pdev);
1137         if (err)
1138                 free_pdev(pdev);
1139
1140 out:
1141         return err;
1142 }
1143
1144 static int pcifront_xenbus_remove(struct xenbus_device *xdev)
1145 {
1146         struct pcifront_device *pdev = dev_get_drvdata(&xdev->dev);
1147         if (pdev)
1148                 free_pdev(pdev);
1149
1150         return 0;
1151 }
1152
1153 static const struct xenbus_device_id xenpci_ids[] = {
1154         {"pci"},
1155         {""},
1156 };
1157
1158 static struct xenbus_driver xenpci_driver = {
1159         .name                   = "pcifront",
1160         .ids                    = xenpci_ids,
1161         .probe                  = pcifront_xenbus_probe,
1162         .remove                 = pcifront_xenbus_remove,
1163         .otherend_changed       = pcifront_backend_changed,
1164 };
1165
1166 static int __init pcifront_init(void)
1167 {
1168         if (!xen_pv_domain() || xen_initial_domain())
1169                 return -ENODEV;
1170
1171         if (!xen_has_pv_devices())
1172                 return -ENODEV;
1173
1174         pci_frontend_registrar(1 /* enable */);
1175
1176         return xenbus_register_frontend(&xenpci_driver);
1177 }
1178
1179 static void __exit pcifront_cleanup(void)
1180 {
1181         xenbus_unregister_driver(&xenpci_driver);
1182         pci_frontend_registrar(0 /* disable */);
1183 }
1184 module_init(pcifront_init);
1185 module_exit(pcifront_cleanup);
1186
1187 MODULE_DESCRIPTION("Xen PCI passthrough frontend.");
1188 MODULE_LICENSE("GPL");
1189 MODULE_ALIAS("xen:pci");