Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/drivers/virtio/virtio_mmio.c

  1 /*
  2  * Virtio memory mapped device driver
  3  *
  4  * Copyright 2011, ARM Ltd.
  5  *
  6  * This module allows virtio devices to be used over a virtual, memory mapped
  7  * platform device.
  8  *
  9  * The guest device(s) may be instantiated in one of three equivalent ways:
 10  *
 11  * 1. Static platform device in board's code, eg.:
 12  *
 13  *      static struct platform_device v2m_virtio_device = {
 14  *              .name = "virtio-mmio",
 15  *              .id = -1,
 16  *              .num_resources = 2,
 17  *              .resource = (struct resource []) {
 18  *                      {
 19  *                              .start = 0x1001e000,
 20  *                              .end = 0x1001e0ff,
 21  *                              .flags = IORESOURCE_MEM,
 22  *                      }, {
 23  *                              .start = 42 + 32,
 24  *                              .end = 42 + 32,
 25  *                              .flags = IORESOURCE_IRQ,
 26  *                      },
 27  *              }
 28  *      };
 29  *
 30  * 2. Device Tree node, eg.:
 31  *
 32  *              virtio_block@1e000 {
 33  *                      compatible = "virtio,mmio";
 34  *                      reg = <0x1e000 0x100>;
 35  *                      interrupts = <42>;
 36  *              }
 37  *
 38  * 3. Kernel module (or command line) parameter. Can be used more than once -
 39  *    one device will be created for each one. Syntax:
 40  *
 41  *              [virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
 42  *    where:
 43  *              <size>     := size (can use standard suffixes like K, M or G)
 44  *              <baseaddr> := physical base address
 45  *              <irq>      := interrupt number (as passed to request_irq())
 46  *              <id>       := (optional) platform device id
 47  *    eg.:
 48  *              virtio_mmio.device=0x100@0x100b0000:48 \
 49  *                              virtio_mmio.device=1K@0x1001e000:74
 50  *
 51  *
 52  *
 53  * Registers layout (all 32-bit wide):
 54  *
 55  * offset d. name             description
 56  * ------ -- ---------------- -----------------
 57  *
 58  * 0x000  R  MagicValue       Magic value "virt"
 59  * 0x004  R  Version          Device version (current max. 1)
 60  * 0x008  R  DeviceID         Virtio device ID
 61  * 0x00c  R  VendorID         Virtio vendor ID
 62  *
 63  * 0x010  R  HostFeatures     Features supported by the host
 64  * 0x014  W  HostFeaturesSel  Set of host features to access via HostFeatures
 65  *
 66  * 0x020  W  GuestFeatures    Features activated by the guest
 67  * 0x024  W  GuestFeaturesSel Set of activated features to set via GuestFeatures
 68  * 0x028  W  GuestPageSize    Size of guest's memory page in bytes
 69  *
 70  * 0x030  W  QueueSel         Queue selector
 71  * 0x034  R  QueueNumMax      Maximum size of the currently selected queue
 72  * 0x038  W  QueueNum         Queue size for the currently selected queue
 73  * 0x03c  W  QueueAlign       Used Ring alignment for the current queue
 74  * 0x040  RW QueuePFN         PFN for the currently selected queue
 75  *
 76  * 0x050  W  QueueNotify      Queue notifier
 77  * 0x060  R  InterruptStatus  Interrupt status register
 78  * 0x064  W  InterruptACK     Interrupt acknowledge register
 79  * 0x070  RW Status           Device status register
 80  *
 81  * 0x100+ RW                  Device-specific configuration space
 82  *
 83  * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
 84  *
 85  * This work is licensed under the terms of the GNU GPL, version 2 or later.
 86  * See the COPYING file in the top-level directory.
 87  */
 88 
 89 #define pr_fmt(fmt) "virtio-mmio: " fmt
 90 
 91 #include <linux/highmem.h>
 92 #include <linux/interrupt.h>
 93 #include <linux/io.h>
 94 #include <linux/list.h>
 95 #include <linux/module.h>
 96 #include <linux/platform_device.h>
 97 #include <linux/slab.h>
 98 #include <linux/spinlock.h>
 99 #include <linux/virtio.h>
100 #include <linux/virtio_config.h>
101 #include <linux/virtio_mmio.h>
102 #include <linux/virtio_ring.h>
103 
104 
105 
106 /* The alignment to use between consumer and producer parts of vring.
107  * Currently hardcoded to the page size. */
108 #define VIRTIO_MMIO_VRING_ALIGN         PAGE_SIZE
109 
110 
111 
112 #define to_virtio_mmio_device(_plat_dev) \
113         container_of(_plat_dev, struct virtio_mmio_device, vdev)
114 
115 struct virtio_mmio_device {
116         struct virtio_device vdev;
117         struct platform_device *pdev;
118 
119         void __iomem *base;
120         unsigned long version;
121 
122         /* a list of queues so we can dispatch IRQs */
123         spinlock_t lock;
124         struct list_head virtqueues;
125 };
126 
127 struct virtio_mmio_vq_info {
128         /* the actual virtqueue */
129         struct virtqueue *vq;
130 
131         /* the number of entries in the queue */
132         unsigned int num;
133 
134         /* the virtual address of the ring queue */
135         void *queue;
136 
137         /* the list node for the virtqueues list */
138         struct list_head node;
139 };
140 
141 
142 
143 /* Configuration interface */
144 
145 static u32 vm_get_features(struct virtio_device *vdev)
146 {
147         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
148 
149         /* TODO: Features > 32 bits */
150         writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
151 
152         return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
153 }
154 
155 static void vm_finalize_features(struct virtio_device *vdev)
156 {
157         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
158         int i;
159 
160         /* Give virtio_ring a chance to accept features. */
161         vring_transport_features(vdev);
162 
163         for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
164                 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
165                 writel(vdev->features[i],
166                                 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
167         }
168 }
169 
170 static void vm_get(struct virtio_device *vdev, unsigned offset,
171                    void *buf, unsigned len)
172 {
173         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
174         u8 *ptr = buf;
175         int i;
176 
177         for (i = 0; i < len; i++)
178                 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
179 }
180 
181 static void vm_set(struct virtio_device *vdev, unsigned offset,
182                    const void *buf, unsigned len)
183 {
184         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
185         const u8 *ptr = buf;
186         int i;
187 
188         for (i = 0; i < len; i++)
189                 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
190 }
191 
192 static u8 vm_get_status(struct virtio_device *vdev)
193 {
194         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
195 
196         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
197 }
198 
199 static void vm_set_status(struct virtio_device *vdev, u8 status)
200 {
201         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
202 
203         /* We should never be setting status to 0. */
204         BUG_ON(status == 0);
205 
206         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
207 }
208 
209 static void vm_reset(struct virtio_device *vdev)
210 {
211         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
212 
213         /* 0 status means a reset. */
214         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
215 }
216 
217 
218 
219 /* Transport interface */
220 
221 /* the notify function used when creating a virt queue */
222 static bool vm_notify(struct virtqueue *vq)
223 {
224         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
225 
226         /* We write the queue's selector into the notification register to
227          * signal the other end */
228         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
229         return true;
230 }
231 
232 /* Notify all virtqueues on an interrupt. */
233 static irqreturn_t vm_interrupt(int irq, void *opaque)
234 {
235         struct virtio_mmio_device *vm_dev = opaque;
236         struct virtio_mmio_vq_info *info;
237         unsigned long status;
238         unsigned long flags;
239         irqreturn_t ret = IRQ_NONE;
240 
241         /* Read and acknowledge interrupts */
242         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
243         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
244 
245         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
246                 virtio_config_changed(&vm_dev->vdev);
247                 ret = IRQ_HANDLED;
248         }
249 
250         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
251                 spin_lock_irqsave(&vm_dev->lock, flags);
252                 list_for_each_entry(info, &vm_dev->virtqueues, node)
253                         ret |= vring_interrupt(irq, info->vq);
254                 spin_unlock_irqrestore(&vm_dev->lock, flags);
255         }
256 
257         return ret;
258 }
259 
260 
261 
262 static void vm_del_vq(struct virtqueue *vq)
263 {
264         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
265         struct virtio_mmio_vq_info *info = vq->priv;
266         unsigned long flags, size;
267         unsigned int index = vq->index;
268 
269         spin_lock_irqsave(&vm_dev->lock, flags);
270         list_del(&info->node);
271         spin_unlock_irqrestore(&vm_dev->lock, flags);
272 
273         vring_del_virtqueue(vq);
274 
275         /* Select and deactivate the queue */
276         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
277         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
278 
279         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
280         free_pages_exact(info->queue, size);
281         kfree(info);
282 }
283 
284 static void vm_del_vqs(struct virtio_device *vdev)
285 {
286         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
287         struct virtqueue *vq, *n;
288 
289         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
290                 vm_del_vq(vq);
291 
292         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
293 }
294 
295 
296 
297 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
298                                   void (*callback)(struct virtqueue *vq),
299                                   const char *name)
300 {
301         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
302         struct virtio_mmio_vq_info *info;
303         struct virtqueue *vq;
304         unsigned long flags, size;
305         int err;
306 
307         if (!name)
308                 return NULL;
309 
310         /* Select the queue we're interested in */
311         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
312 
313         /* Queue shouldn't already be set up. */
314         if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
315                 err = -ENOENT;
316                 goto error_available;
317         }
318 
319         /* Allocate and fill out our active queue description */
320         info = kmalloc(sizeof(*info), GFP_KERNEL);
321         if (!info) {
322                 err = -ENOMEM;
323                 goto error_kmalloc;
324         }
325 
326         /* Allocate pages for the queue - start with a queue as big as
327          * possible (limited by maximum size allowed by device), drop down
328          * to a minimal size, just big enough to fit descriptor table
329          * and two rings (which makes it "alignment_size * 2")
330          */
331         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
332 
333         /* If the device reports a 0 entry queue, we won't be able to
334          * use it to perform I/O, and vring_new_virtqueue() can't create
335          * empty queues anyway, so don't bother to set up the device.
336          */
337         if (info->num == 0) {
338                 err = -ENOENT;
339                 goto error_alloc_pages;
340         }
341 
342         while (1) {
343                 size = PAGE_ALIGN(vring_size(info->num,
344                                 VIRTIO_MMIO_VRING_ALIGN));
345                 /* Did the last iter shrink the queue below minimum size? */
346                 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
347                         err = -ENOMEM;
348                         goto error_alloc_pages;
349                 }
350 
351                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
352                 if (info->queue)
353                         break;
354 
355                 info->num /= 2;
356         }
357 
358         /* Activate the queue */
359         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
360         writel(VIRTIO_MMIO_VRING_ALIGN,
361                         vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
362         writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
363                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
364 
365         /* Create the vring */
366         vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
367                                  true, info->queue, vm_notify, callback, name);
368         if (!vq) {
369                 err = -ENOMEM;
370                 goto error_new_virtqueue;
371         }
372 
373         vq->priv = info;
374         info->vq = vq;
375 
376         spin_lock_irqsave(&vm_dev->lock, flags);
377         list_add(&info->node, &vm_dev->virtqueues);
378         spin_unlock_irqrestore(&vm_dev->lock, flags);
379 
380         return vq;
381 
382 error_new_virtqueue:
383         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
384         free_pages_exact(info->queue, size);
385 error_alloc_pages:
386         kfree(info);
387 error_kmalloc:
388 error_available:
389         return ERR_PTR(err);
390 }
391 
392 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
393                        struct virtqueue *vqs[],
394                        vq_callback_t *callbacks[],
395                        const char *names[])
396 {
397         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
398         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
399         int i, err;
400 
401         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
402                         dev_name(&vdev->dev), vm_dev);
403         if (err)
404                 return err;
405 
406         for (i = 0; i < nvqs; ++i) {
407                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
408                 if (IS_ERR(vqs[i])) {
409                         vm_del_vqs(vdev);
410                         return PTR_ERR(vqs[i]);
411                 }
412         }
413 
414         return 0;
415 }
416 
417 static const char *vm_bus_name(struct virtio_device *vdev)
418 {
419         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
420 
421         return vm_dev->pdev->name;
422 }
423 
424 static const struct virtio_config_ops virtio_mmio_config_ops = {
425         .get            = vm_get,
426         .set            = vm_set,
427         .get_status     = vm_get_status,
428         .set_status     = vm_set_status,
429         .reset          = vm_reset,
430         .find_vqs       = vm_find_vqs,
431         .del_vqs        = vm_del_vqs,
432         .get_features   = vm_get_features,
433         .finalize_features = vm_finalize_features,
434         .bus_name       = vm_bus_name,
435 };
436 
437 
438 
439 /* Platform device */
440 
441 static int virtio_mmio_probe(struct platform_device *pdev)
442 {
443         struct virtio_mmio_device *vm_dev;
444         struct resource *mem;
445         unsigned long magic;
446 
447         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
448         if (!mem)
449                 return -EINVAL;
450 
451         if (!devm_request_mem_region(&pdev->dev, mem->start,
452                         resource_size(mem), pdev->name))
453                 return -EBUSY;
454 
455         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
456         if (!vm_dev)
457                 return  -ENOMEM;
458 
459         vm_dev->vdev.dev.parent = &pdev->dev;
460         vm_dev->vdev.config = &virtio_mmio_config_ops;
461         vm_dev->pdev = pdev;
462         INIT_LIST_HEAD(&vm_dev->virtqueues);
463         spin_lock_init(&vm_dev->lock);
464 
465         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
466         if (vm_dev->base == NULL)
467                 return -EFAULT;
468 
469         /* Check magic value */
470         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
471         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
472                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
473                 return -ENODEV;
474         }
475 
476         /* Check device version */
477         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
478         if (vm_dev->version != 1) {
479                 dev_err(&pdev->dev, "Version %ld not supported!\n",
480                                 vm_dev->version);
481                 return -ENXIO;
482         }
483 
484         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
485         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
486 
487         writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
488 
489         platform_set_drvdata(pdev, vm_dev);
490 
491         return register_virtio_device(&vm_dev->vdev);
492 }
493 
494 static int virtio_mmio_remove(struct platform_device *pdev)
495 {
496         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
497 
498         unregister_virtio_device(&vm_dev->vdev);
499 
500         return 0;
501 }
502 
503 
504 
505 /* Devices list parameter */
506 
507 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
508 
509 static struct device vm_cmdline_parent = {
510         .init_name = "virtio-mmio-cmdline",
511 };
512 
513 static int vm_cmdline_parent_registered;
514 static int vm_cmdline_id;
515 
516 static int vm_cmdline_set(const char *device,
517                 const struct kernel_param *kp)
518 {
519         int err;
520         struct resource resources[2] = {};
521         char *str;
522         long long int base, size;
523         unsigned int irq;
524         int processed, consumed = 0;
525         struct platform_device *pdev;
526 
527         /* Consume "size" part of the command line parameter */
528         size = memparse(device, &str);
529 
530         /* Get "@<base>:<irq>[:<id>]" chunks */
531         processed = sscanf(str, "@%lli:%u%n:%d%n",
532                         &base, &irq, &consumed,
533                         &vm_cmdline_id, &consumed);
534 
535         /*
536          * sscanf() must processes at least 2 chunks; also there
537          * must be no extra characters after the last chunk, so
538          * str[consumed] must be '\0'
539          */
540         if (processed < 2 || str[consumed])
541                 return -EINVAL;
542 
543         resources[0].flags = IORESOURCE_MEM;
544         resources[0].start = base;
545         resources[0].end = base + size - 1;
546 
547         resources[1].flags = IORESOURCE_IRQ;
548         resources[1].start = resources[1].end = irq;
549 
550         if (!vm_cmdline_parent_registered) {
551                 err = device_register(&vm_cmdline_parent);
552                 if (err) {
553                         pr_err("Failed to register parent device!\n");
554                         return err;
555                 }
556                 vm_cmdline_parent_registered = 1;
557         }
558 
559         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
560                        vm_cmdline_id,
561                        (unsigned long long)resources[0].start,
562                        (unsigned long long)resources[0].end,
563                        (int)resources[1].start);
564 
565         pdev = platform_device_register_resndata(&vm_cmdline_parent,
566                         "virtio-mmio", vm_cmdline_id++,
567                         resources, ARRAY_SIZE(resources), NULL, 0);
568         if (IS_ERR(pdev))
569                 return PTR_ERR(pdev);
570 
571         return 0;
572 }
573 
574 static int vm_cmdline_get_device(struct device *dev, void *data)
575 {
576         char *buffer = data;
577         unsigned int len = strlen(buffer);
578         struct platform_device *pdev = to_platform_device(dev);
579 
580         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
581                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
582                         (unsigned long long)pdev->resource[0].start,
583                         (unsigned long long)pdev->resource[1].start,
584                         pdev->id);
585         return 0;
586 }
587 
588 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
589 {
590         buffer[0] = '\0';
591         device_for_each_child(&vm_cmdline_parent, buffer,
592                         vm_cmdline_get_device);
593         return strlen(buffer) + 1;
594 }
595 
596 static struct kernel_param_ops vm_cmdline_param_ops = {
597         .set = vm_cmdline_set,
598         .get = vm_cmdline_get,
599 };
600 
601 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
602 
603 static int vm_unregister_cmdline_device(struct device *dev,
604                 void *data)
605 {
606         platform_device_unregister(to_platform_device(dev));
607 
608         return 0;
609 }
610 
611 static void vm_unregister_cmdline_devices(void)
612 {
613         if (vm_cmdline_parent_registered) {
614                 device_for_each_child(&vm_cmdline_parent, NULL,
615                                 vm_unregister_cmdline_device);
616                 device_unregister(&vm_cmdline_parent);
617                 vm_cmdline_parent_registered = 0;
618         }
619 }
620 
621 #else
622 
623 static void vm_unregister_cmdline_devices(void)
624 {
625 }
626 
627 #endif
628 
629 /* Platform driver */
630 
631 static struct of_device_id virtio_mmio_match[] = {
632         { .compatible = "virtio,mmio", },
633         {},
634 };
635 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
636 
637 static struct platform_driver virtio_mmio_driver = {
638         .probe          = virtio_mmio_probe,
639         .remove         = virtio_mmio_remove,
640         .driver         = {
641                 .name   = "virtio-mmio",
642                 .owner  = THIS_MODULE,
643                 .of_match_table = virtio_mmio_match,
644         },
645 };
646 
647 static int __init virtio_mmio_init(void)
648 {
649         return platform_driver_register(&virtio_mmio_driver);
650 }
651 
652 static void __exit virtio_mmio_exit(void)
653 {
654         platform_driver_unregister(&virtio_mmio_driver);
655         vm_unregister_cmdline_devices();
656 }
657 
658 module_init(virtio_mmio_init);
659 module_exit(virtio_mmio_exit);
660 
661 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
662 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
663 MODULE_LICENSE("GPL");
664 

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