Version:  2.0.40 2.2.26 2.4.37 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 3.19

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 u64 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 int vm_finalize_features(struct virtio_device *vdev)
156 {
157         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
158 
159         /* Give virtio_ring a chance to accept features. */
160         vring_transport_features(vdev);
161 
162         /* Make sure we don't have any features > 32 bits! */
163         BUG_ON((u32)vdev->features != vdev->features);
164 
165         writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
166         writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
167 
168         return 0;
169 }
170 
171 static void vm_get(struct virtio_device *vdev, unsigned offset,
172                    void *buf, unsigned len)
173 {
174         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
175         u8 *ptr = buf;
176         int i;
177 
178         for (i = 0; i < len; i++)
179                 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
180 }
181 
182 static void vm_set(struct virtio_device *vdev, unsigned offset,
183                    const void *buf, unsigned len)
184 {
185         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
186         const u8 *ptr = buf;
187         int i;
188 
189         for (i = 0; i < len; i++)
190                 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
191 }
192 
193 static u8 vm_get_status(struct virtio_device *vdev)
194 {
195         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
196 
197         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
198 }
199 
200 static void vm_set_status(struct virtio_device *vdev, u8 status)
201 {
202         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
203 
204         /* We should never be setting status to 0. */
205         BUG_ON(status == 0);
206 
207         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
208 }
209 
210 static void vm_reset(struct virtio_device *vdev)
211 {
212         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
213 
214         /* 0 status means a reset. */
215         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
216 }
217 
218 
219 
220 /* Transport interface */
221 
222 /* the notify function used when creating a virt queue */
223 static bool vm_notify(struct virtqueue *vq)
224 {
225         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
226 
227         /* We write the queue's selector into the notification register to
228          * signal the other end */
229         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
230         return true;
231 }
232 
233 /* Notify all virtqueues on an interrupt. */
234 static irqreturn_t vm_interrupt(int irq, void *opaque)
235 {
236         struct virtio_mmio_device *vm_dev = opaque;
237         struct virtio_mmio_vq_info *info;
238         unsigned long status;
239         unsigned long flags;
240         irqreturn_t ret = IRQ_NONE;
241 
242         /* Read and acknowledge interrupts */
243         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
244         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
245 
246         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
247                 virtio_config_changed(&vm_dev->vdev);
248                 ret = IRQ_HANDLED;
249         }
250 
251         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
252                 spin_lock_irqsave(&vm_dev->lock, flags);
253                 list_for_each_entry(info, &vm_dev->virtqueues, node)
254                         ret |= vring_interrupt(irq, info->vq);
255                 spin_unlock_irqrestore(&vm_dev->lock, flags);
256         }
257 
258         return ret;
259 }
260 
261 
262 
263 static void vm_del_vq(struct virtqueue *vq)
264 {
265         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
266         struct virtio_mmio_vq_info *info = vq->priv;
267         unsigned long flags, size;
268         unsigned int index = vq->index;
269 
270         spin_lock_irqsave(&vm_dev->lock, flags);
271         list_del(&info->node);
272         spin_unlock_irqrestore(&vm_dev->lock, flags);
273 
274         vring_del_virtqueue(vq);
275 
276         /* Select and deactivate the queue */
277         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
278         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
279 
280         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
281         free_pages_exact(info->queue, size);
282         kfree(info);
283 }
284 
285 static void vm_del_vqs(struct virtio_device *vdev)
286 {
287         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
288         struct virtqueue *vq, *n;
289 
290         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
291                 vm_del_vq(vq);
292 
293         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
294 }
295 
296 
297 
298 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
299                                   void (*callback)(struct virtqueue *vq),
300                                   const char *name)
301 {
302         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
303         struct virtio_mmio_vq_info *info;
304         struct virtqueue *vq;
305         unsigned long flags, size;
306         int err;
307 
308         if (!name)
309                 return NULL;
310 
311         /* Select the queue we're interested in */
312         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
313 
314         /* Queue shouldn't already be set up. */
315         if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
316                 err = -ENOENT;
317                 goto error_available;
318         }
319 
320         /* Allocate and fill out our active queue description */
321         info = kmalloc(sizeof(*info), GFP_KERNEL);
322         if (!info) {
323                 err = -ENOMEM;
324                 goto error_kmalloc;
325         }
326 
327         /* Allocate pages for the queue - start with a queue as big as
328          * possible (limited by maximum size allowed by device), drop down
329          * to a minimal size, just big enough to fit descriptor table
330          * and two rings (which makes it "alignment_size * 2")
331          */
332         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
333 
334         /* If the device reports a 0 entry queue, we won't be able to
335          * use it to perform I/O, and vring_new_virtqueue() can't create
336          * empty queues anyway, so don't bother to set up the device.
337          */
338         if (info->num == 0) {
339                 err = -ENOENT;
340                 goto error_alloc_pages;
341         }
342 
343         while (1) {
344                 size = PAGE_ALIGN(vring_size(info->num,
345                                 VIRTIO_MMIO_VRING_ALIGN));
346                 /* Did the last iter shrink the queue below minimum size? */
347                 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
348                         err = -ENOMEM;
349                         goto error_alloc_pages;
350                 }
351 
352                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
353                 if (info->queue)
354                         break;
355 
356                 info->num /= 2;
357         }
358 
359         /* Activate the queue */
360         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
361         writel(VIRTIO_MMIO_VRING_ALIGN,
362                         vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
363         writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
364                         vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
365 
366         /* Create the vring */
367         vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
368                                  true, info->queue, vm_notify, callback, name);
369         if (!vq) {
370                 err = -ENOMEM;
371                 goto error_new_virtqueue;
372         }
373 
374         vq->priv = info;
375         info->vq = vq;
376 
377         spin_lock_irqsave(&vm_dev->lock, flags);
378         list_add(&info->node, &vm_dev->virtqueues);
379         spin_unlock_irqrestore(&vm_dev->lock, flags);
380 
381         return vq;
382 
383 error_new_virtqueue:
384         writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
385         free_pages_exact(info->queue, size);
386 error_alloc_pages:
387         kfree(info);
388 error_kmalloc:
389 error_available:
390         return ERR_PTR(err);
391 }
392 
393 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
394                        struct virtqueue *vqs[],
395                        vq_callback_t *callbacks[],
396                        const char *names[])
397 {
398         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
399         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
400         int i, err;
401 
402         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
403                         dev_name(&vdev->dev), vm_dev);
404         if (err)
405                 return err;
406 
407         for (i = 0; i < nvqs; ++i) {
408                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
409                 if (IS_ERR(vqs[i])) {
410                         vm_del_vqs(vdev);
411                         return PTR_ERR(vqs[i]);
412                 }
413         }
414 
415         return 0;
416 }
417 
418 static const char *vm_bus_name(struct virtio_device *vdev)
419 {
420         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
421 
422         return vm_dev->pdev->name;
423 }
424 
425 static const struct virtio_config_ops virtio_mmio_config_ops = {
426         .get            = vm_get,
427         .set            = vm_set,
428         .get_status     = vm_get_status,
429         .set_status     = vm_set_status,
430         .reset          = vm_reset,
431         .find_vqs       = vm_find_vqs,
432         .del_vqs        = vm_del_vqs,
433         .get_features   = vm_get_features,
434         .finalize_features = vm_finalize_features,
435         .bus_name       = vm_bus_name,
436 };
437 
438 
439 
440 /* Platform device */
441 
442 static int virtio_mmio_probe(struct platform_device *pdev)
443 {
444         struct virtio_mmio_device *vm_dev;
445         struct resource *mem;
446         unsigned long magic;
447 
448         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
449         if (!mem)
450                 return -EINVAL;
451 
452         if (!devm_request_mem_region(&pdev->dev, mem->start,
453                         resource_size(mem), pdev->name))
454                 return -EBUSY;
455 
456         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
457         if (!vm_dev)
458                 return  -ENOMEM;
459 
460         vm_dev->vdev.dev.parent = &pdev->dev;
461         vm_dev->vdev.config = &virtio_mmio_config_ops;
462         vm_dev->pdev = pdev;
463         INIT_LIST_HEAD(&vm_dev->virtqueues);
464         spin_lock_init(&vm_dev->lock);
465 
466         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
467         if (vm_dev->base == NULL)
468                 return -EFAULT;
469 
470         /* Check magic value */
471         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
472         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
473                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
474                 return -ENODEV;
475         }
476 
477         /* Check device version */
478         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
479         if (vm_dev->version != 1) {
480                 dev_err(&pdev->dev, "Version %ld not supported!\n",
481                                 vm_dev->version);
482                 return -ENXIO;
483         }
484 
485         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
486         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
487 
488         writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
489 
490         platform_set_drvdata(pdev, vm_dev);
491 
492         return register_virtio_device(&vm_dev->vdev);
493 }
494 
495 static int virtio_mmio_remove(struct platform_device *pdev)
496 {
497         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
498 
499         unregister_virtio_device(&vm_dev->vdev);
500 
501         return 0;
502 }
503 
504 
505 
506 /* Devices list parameter */
507 
508 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
509 
510 static struct device vm_cmdline_parent = {
511         .init_name = "virtio-mmio-cmdline",
512 };
513 
514 static int vm_cmdline_parent_registered;
515 static int vm_cmdline_id;
516 
517 static int vm_cmdline_set(const char *device,
518                 const struct kernel_param *kp)
519 {
520         int err;
521         struct resource resources[2] = {};
522         char *str;
523         long long int base, size;
524         unsigned int irq;
525         int processed, consumed = 0;
526         struct platform_device *pdev;
527 
528         /* Consume "size" part of the command line parameter */
529         size = memparse(device, &str);
530 
531         /* Get "@<base>:<irq>[:<id>]" chunks */
532         processed = sscanf(str, "@%lli:%u%n:%d%n",
533                         &base, &irq, &consumed,
534                         &vm_cmdline_id, &consumed);
535 
536         /*
537          * sscanf() must processes at least 2 chunks; also there
538          * must be no extra characters after the last chunk, so
539          * str[consumed] must be '\0'
540          */
541         if (processed < 2 || str[consumed])
542                 return -EINVAL;
543 
544         resources[0].flags = IORESOURCE_MEM;
545         resources[0].start = base;
546         resources[0].end = base + size - 1;
547 
548         resources[1].flags = IORESOURCE_IRQ;
549         resources[1].start = resources[1].end = irq;
550 
551         if (!vm_cmdline_parent_registered) {
552                 err = device_register(&vm_cmdline_parent);
553                 if (err) {
554                         pr_err("Failed to register parent device!\n");
555                         return err;
556                 }
557                 vm_cmdline_parent_registered = 1;
558         }
559 
560         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
561                        vm_cmdline_id,
562                        (unsigned long long)resources[0].start,
563                        (unsigned long long)resources[0].end,
564                        (int)resources[1].start);
565 
566         pdev = platform_device_register_resndata(&vm_cmdline_parent,
567                         "virtio-mmio", vm_cmdline_id++,
568                         resources, ARRAY_SIZE(resources), NULL, 0);
569         if (IS_ERR(pdev))
570                 return PTR_ERR(pdev);
571 
572         return 0;
573 }
574 
575 static int vm_cmdline_get_device(struct device *dev, void *data)
576 {
577         char *buffer = data;
578         unsigned int len = strlen(buffer);
579         struct platform_device *pdev = to_platform_device(dev);
580 
581         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
582                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
583                         (unsigned long long)pdev->resource[0].start,
584                         (unsigned long long)pdev->resource[1].start,
585                         pdev->id);
586         return 0;
587 }
588 
589 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
590 {
591         buffer[0] = '\0';
592         device_for_each_child(&vm_cmdline_parent, buffer,
593                         vm_cmdline_get_device);
594         return strlen(buffer) + 1;
595 }
596 
597 static struct kernel_param_ops vm_cmdline_param_ops = {
598         .set = vm_cmdline_set,
599         .get = vm_cmdline_get,
600 };
601 
602 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
603 
604 static int vm_unregister_cmdline_device(struct device *dev,
605                 void *data)
606 {
607         platform_device_unregister(to_platform_device(dev));
608 
609         return 0;
610 }
611 
612 static void vm_unregister_cmdline_devices(void)
613 {
614         if (vm_cmdline_parent_registered) {
615                 device_for_each_child(&vm_cmdline_parent, NULL,
616                                 vm_unregister_cmdline_device);
617                 device_unregister(&vm_cmdline_parent);
618                 vm_cmdline_parent_registered = 0;
619         }
620 }
621 
622 #else
623 
624 static void vm_unregister_cmdline_devices(void)
625 {
626 }
627 
628 #endif
629 
630 /* Platform driver */
631 
632 static struct of_device_id virtio_mmio_match[] = {
633         { .compatible = "virtio,mmio", },
634         {},
635 };
636 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
637 
638 static struct platform_driver virtio_mmio_driver = {
639         .probe          = virtio_mmio_probe,
640         .remove         = virtio_mmio_remove,
641         .driver         = {
642                 .name   = "virtio-mmio",
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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