Version:  2.0.40 2.2.26 2.4.37 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 4.0 4.1 4.2

Linux/drivers/virtio/virtio_mmio.c

  1 /*
  2  * Virtio memory mapped device driver
  3  *
  4  * Copyright 2011-2014, 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  * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
 54  *
 55  * This work is licensed under the terms of the GNU GPL, version 2 or later.
 56  * See the COPYING file in the top-level directory.
 57  */
 58 
 59 #define pr_fmt(fmt) "virtio-mmio: " fmt
 60 
 61 #include <linux/highmem.h>
 62 #include <linux/interrupt.h>
 63 #include <linux/io.h>
 64 #include <linux/list.h>
 65 #include <linux/module.h>
 66 #include <linux/platform_device.h>
 67 #include <linux/slab.h>
 68 #include <linux/spinlock.h>
 69 #include <linux/virtio.h>
 70 #include <linux/virtio_config.h>
 71 #include <linux/virtio_mmio.h>
 72 #include <linux/virtio_ring.h>
 73 
 74 
 75 
 76 /* The alignment to use between consumer and producer parts of vring.
 77  * Currently hardcoded to the page size. */
 78 #define VIRTIO_MMIO_VRING_ALIGN         PAGE_SIZE
 79 
 80 
 81 
 82 #define to_virtio_mmio_device(_plat_dev) \
 83         container_of(_plat_dev, struct virtio_mmio_device, vdev)
 84 
 85 struct virtio_mmio_device {
 86         struct virtio_device vdev;
 87         struct platform_device *pdev;
 88 
 89         void __iomem *base;
 90         unsigned long version;
 91 
 92         /* a list of queues so we can dispatch IRQs */
 93         spinlock_t lock;
 94         struct list_head virtqueues;
 95 };
 96 
 97 struct virtio_mmio_vq_info {
 98         /* the actual virtqueue */
 99         struct virtqueue *vq;
100 
101         /* the number of entries in the queue */
102         unsigned int num;
103 
104         /* the virtual address of the ring queue */
105         void *queue;
106 
107         /* the list node for the virtqueues list */
108         struct list_head node;
109 };
110 
111 
112 
113 /* Configuration interface */
114 
115 static u64 vm_get_features(struct virtio_device *vdev)
116 {
117         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
118         u64 features;
119 
120         writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
121         features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
122         features <<= 32;
123 
124         writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
125         features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
126 
127         return features;
128 }
129 
130 static int vm_finalize_features(struct virtio_device *vdev)
131 {
132         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
133 
134         /* Give virtio_ring a chance to accept features. */
135         vring_transport_features(vdev);
136 
137         /* Make sure there is are no mixed devices */
138         if (vm_dev->version == 2 &&
139                         !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
140                 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
141                 return -EINVAL;
142         }
143 
144         writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
145         writel((u32)(vdev->features >> 32),
146                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
147 
148         writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
149         writel((u32)vdev->features,
150                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
151 
152         return 0;
153 }
154 
155 static void vm_get(struct virtio_device *vdev, unsigned offset,
156                    void *buf, unsigned len)
157 {
158         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
159         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
160         u8 b;
161         __le16 w;
162         __le32 l;
163 
164         if (vm_dev->version == 1) {
165                 u8 *ptr = buf;
166                 int i;
167 
168                 for (i = 0; i < len; i++)
169                         ptr[i] = readb(base + offset + i);
170                 return;
171         }
172 
173         switch (len) {
174         case 1:
175                 b = readb(base + offset);
176                 memcpy(buf, &b, sizeof b);
177                 break;
178         case 2:
179                 w = cpu_to_le16(readw(base + offset));
180                 memcpy(buf, &w, sizeof w);
181                 break;
182         case 4:
183                 l = cpu_to_le32(readl(base + offset));
184                 memcpy(buf, &l, sizeof l);
185                 break;
186         case 8:
187                 l = cpu_to_le32(readl(base + offset));
188                 memcpy(buf, &l, sizeof l);
189                 l = cpu_to_le32(ioread32(base + offset + sizeof l));
190                 memcpy(buf + sizeof l, &l, sizeof l);
191                 break;
192         default:
193                 BUG();
194         }
195 }
196 
197 static void vm_set(struct virtio_device *vdev, unsigned offset,
198                    const void *buf, unsigned len)
199 {
200         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
201         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
202         u8 b;
203         __le16 w;
204         __le32 l;
205 
206         if (vm_dev->version == 1) {
207                 const u8 *ptr = buf;
208                 int i;
209 
210                 for (i = 0; i < len; i++)
211                         writeb(ptr[i], base + offset + i);
212 
213                 return;
214         }
215 
216         switch (len) {
217         case 1:
218                 memcpy(&b, buf, sizeof b);
219                 writeb(b, base + offset);
220                 break;
221         case 2:
222                 memcpy(&w, buf, sizeof w);
223                 writew(le16_to_cpu(w), base + offset);
224                 break;
225         case 4:
226                 memcpy(&l, buf, sizeof l);
227                 writel(le32_to_cpu(l), base + offset);
228                 break;
229         case 8:
230                 memcpy(&l, buf, sizeof l);
231                 writel(le32_to_cpu(l), base + offset);
232                 memcpy(&l, buf + sizeof l, sizeof l);
233                 writel(le32_to_cpu(l), base + offset + sizeof l);
234                 break;
235         default:
236                 BUG();
237         }
238 }
239 
240 static u32 vm_generation(struct virtio_device *vdev)
241 {
242         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
243 
244         if (vm_dev->version == 1)
245                 return 0;
246         else
247                 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
248 }
249 
250 static u8 vm_get_status(struct virtio_device *vdev)
251 {
252         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
253 
254         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
255 }
256 
257 static void vm_set_status(struct virtio_device *vdev, u8 status)
258 {
259         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
260 
261         /* We should never be setting status to 0. */
262         BUG_ON(status == 0);
263 
264         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
265 }
266 
267 static void vm_reset(struct virtio_device *vdev)
268 {
269         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
270 
271         /* 0 status means a reset. */
272         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
273 }
274 
275 
276 
277 /* Transport interface */
278 
279 /* the notify function used when creating a virt queue */
280 static bool vm_notify(struct virtqueue *vq)
281 {
282         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
283 
284         /* We write the queue's selector into the notification register to
285          * signal the other end */
286         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
287         return true;
288 }
289 
290 /* Notify all virtqueues on an interrupt. */
291 static irqreturn_t vm_interrupt(int irq, void *opaque)
292 {
293         struct virtio_mmio_device *vm_dev = opaque;
294         struct virtio_mmio_vq_info *info;
295         unsigned long status;
296         unsigned long flags;
297         irqreturn_t ret = IRQ_NONE;
298 
299         /* Read and acknowledge interrupts */
300         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
301         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
302 
303         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
304                 virtio_config_changed(&vm_dev->vdev);
305                 ret = IRQ_HANDLED;
306         }
307 
308         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
309                 spin_lock_irqsave(&vm_dev->lock, flags);
310                 list_for_each_entry(info, &vm_dev->virtqueues, node)
311                         ret |= vring_interrupt(irq, info->vq);
312                 spin_unlock_irqrestore(&vm_dev->lock, flags);
313         }
314 
315         return ret;
316 }
317 
318 
319 
320 static void vm_del_vq(struct virtqueue *vq)
321 {
322         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
323         struct virtio_mmio_vq_info *info = vq->priv;
324         unsigned long flags, size;
325         unsigned int index = vq->index;
326 
327         spin_lock_irqsave(&vm_dev->lock, flags);
328         list_del(&info->node);
329         spin_unlock_irqrestore(&vm_dev->lock, flags);
330 
331         vring_del_virtqueue(vq);
332 
333         /* Select and deactivate the queue */
334         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
335         if (vm_dev->version == 1) {
336                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
337         } else {
338                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
339                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
340         }
341 
342         size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
343         free_pages_exact(info->queue, size);
344         kfree(info);
345 }
346 
347 static void vm_del_vqs(struct virtio_device *vdev)
348 {
349         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
350         struct virtqueue *vq, *n;
351 
352         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
353                 vm_del_vq(vq);
354 
355         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
356 }
357 
358 
359 
360 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
361                                   void (*callback)(struct virtqueue *vq),
362                                   const char *name)
363 {
364         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
365         struct virtio_mmio_vq_info *info;
366         struct virtqueue *vq;
367         unsigned long flags, size;
368         int err;
369 
370         if (!name)
371                 return NULL;
372 
373         /* Select the queue we're interested in */
374         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
375 
376         /* Queue shouldn't already be set up. */
377         if (readl(vm_dev->base + (vm_dev->version == 1 ?
378                         VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
379                 err = -ENOENT;
380                 goto error_available;
381         }
382 
383         /* Allocate and fill out our active queue description */
384         info = kmalloc(sizeof(*info), GFP_KERNEL);
385         if (!info) {
386                 err = -ENOMEM;
387                 goto error_kmalloc;
388         }
389 
390         /* Allocate pages for the queue - start with a queue as big as
391          * possible (limited by maximum size allowed by device), drop down
392          * to a minimal size, just big enough to fit descriptor table
393          * and two rings (which makes it "alignment_size * 2")
394          */
395         info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
396 
397         /* If the device reports a 0 entry queue, we won't be able to
398          * use it to perform I/O, and vring_new_virtqueue() can't create
399          * empty queues anyway, so don't bother to set up the device.
400          */
401         if (info->num == 0) {
402                 err = -ENOENT;
403                 goto error_alloc_pages;
404         }
405 
406         while (1) {
407                 size = PAGE_ALIGN(vring_size(info->num,
408                                 VIRTIO_MMIO_VRING_ALIGN));
409                 /* Did the last iter shrink the queue below minimum size? */
410                 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
411                         err = -ENOMEM;
412                         goto error_alloc_pages;
413                 }
414 
415                 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
416                 if (info->queue)
417                         break;
418 
419                 info->num /= 2;
420         }
421 
422         /* Create the vring */
423         vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
424                                  true, info->queue, vm_notify, callback, name);
425         if (!vq) {
426                 err = -ENOMEM;
427                 goto error_new_virtqueue;
428         }
429 
430         /* Activate the queue */
431         writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
432         if (vm_dev->version == 1) {
433                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
434                 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
435                                 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
436         } else {
437                 u64 addr;
438 
439                 addr = virt_to_phys(info->queue);
440                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
441                 writel((u32)(addr >> 32),
442                                 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
443 
444                 addr = virt_to_phys(virtqueue_get_avail(vq));
445                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
446                 writel((u32)(addr >> 32),
447                                 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
448 
449                 addr = virt_to_phys(virtqueue_get_used(vq));
450                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
451                 writel((u32)(addr >> 32),
452                                 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
453 
454                 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
455         }
456 
457         vq->priv = info;
458         info->vq = vq;
459 
460         spin_lock_irqsave(&vm_dev->lock, flags);
461         list_add(&info->node, &vm_dev->virtqueues);
462         spin_unlock_irqrestore(&vm_dev->lock, flags);
463 
464         return vq;
465 
466 error_new_virtqueue:
467         if (vm_dev->version == 1) {
468                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
469         } else {
470                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
471                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
472         }
473         free_pages_exact(info->queue, size);
474 error_alloc_pages:
475         kfree(info);
476 error_kmalloc:
477 error_available:
478         return ERR_PTR(err);
479 }
480 
481 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
482                        struct virtqueue *vqs[],
483                        vq_callback_t *callbacks[],
484                        const char *names[])
485 {
486         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
487         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
488         int i, err;
489 
490         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
491                         dev_name(&vdev->dev), vm_dev);
492         if (err)
493                 return err;
494 
495         for (i = 0; i < nvqs; ++i) {
496                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
497                 if (IS_ERR(vqs[i])) {
498                         vm_del_vqs(vdev);
499                         return PTR_ERR(vqs[i]);
500                 }
501         }
502 
503         return 0;
504 }
505 
506 static const char *vm_bus_name(struct virtio_device *vdev)
507 {
508         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
509 
510         return vm_dev->pdev->name;
511 }
512 
513 static const struct virtio_config_ops virtio_mmio_config_ops = {
514         .get            = vm_get,
515         .set            = vm_set,
516         .generation     = vm_generation,
517         .get_status     = vm_get_status,
518         .set_status     = vm_set_status,
519         .reset          = vm_reset,
520         .find_vqs       = vm_find_vqs,
521         .del_vqs        = vm_del_vqs,
522         .get_features   = vm_get_features,
523         .finalize_features = vm_finalize_features,
524         .bus_name       = vm_bus_name,
525 };
526 
527 
528 
529 /* Platform device */
530 
531 static int virtio_mmio_probe(struct platform_device *pdev)
532 {
533         struct virtio_mmio_device *vm_dev;
534         struct resource *mem;
535         unsigned long magic;
536 
537         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
538         if (!mem)
539                 return -EINVAL;
540 
541         if (!devm_request_mem_region(&pdev->dev, mem->start,
542                         resource_size(mem), pdev->name))
543                 return -EBUSY;
544 
545         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
546         if (!vm_dev)
547                 return  -ENOMEM;
548 
549         vm_dev->vdev.dev.parent = &pdev->dev;
550         vm_dev->vdev.config = &virtio_mmio_config_ops;
551         vm_dev->pdev = pdev;
552         INIT_LIST_HEAD(&vm_dev->virtqueues);
553         spin_lock_init(&vm_dev->lock);
554 
555         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
556         if (vm_dev->base == NULL)
557                 return -EFAULT;
558 
559         /* Check magic value */
560         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
561         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
562                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
563                 return -ENODEV;
564         }
565 
566         /* Check device version */
567         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
568         if (vm_dev->version < 1 || vm_dev->version > 2) {
569                 dev_err(&pdev->dev, "Version %ld not supported!\n",
570                                 vm_dev->version);
571                 return -ENXIO;
572         }
573 
574         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
575         if (vm_dev->vdev.id.device == 0) {
576                 /*
577                  * virtio-mmio device with an ID 0 is a (dummy) placeholder
578                  * with no function. End probing now with no error reported.
579                  */
580                 return -ENODEV;
581         }
582         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
583 
584         if (vm_dev->version == 1)
585                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
586 
587         platform_set_drvdata(pdev, vm_dev);
588 
589         return register_virtio_device(&vm_dev->vdev);
590 }
591 
592 static int virtio_mmio_remove(struct platform_device *pdev)
593 {
594         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
595 
596         unregister_virtio_device(&vm_dev->vdev);
597 
598         return 0;
599 }
600 
601 
602 
603 /* Devices list parameter */
604 
605 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
606 
607 static struct device vm_cmdline_parent = {
608         .init_name = "virtio-mmio-cmdline",
609 };
610 
611 static int vm_cmdline_parent_registered;
612 static int vm_cmdline_id;
613 
614 static int vm_cmdline_set(const char *device,
615                 const struct kernel_param *kp)
616 {
617         int err;
618         struct resource resources[2] = {};
619         char *str;
620         long long int base, size;
621         unsigned int irq;
622         int processed, consumed = 0;
623         struct platform_device *pdev;
624 
625         /* Consume "size" part of the command line parameter */
626         size = memparse(device, &str);
627 
628         /* Get "@<base>:<irq>[:<id>]" chunks */
629         processed = sscanf(str, "@%lli:%u%n:%d%n",
630                         &base, &irq, &consumed,
631                         &vm_cmdline_id, &consumed);
632 
633         /*
634          * sscanf() must processes at least 2 chunks; also there
635          * must be no extra characters after the last chunk, so
636          * str[consumed] must be '\0'
637          */
638         if (processed < 2 || str[consumed])
639                 return -EINVAL;
640 
641         resources[0].flags = IORESOURCE_MEM;
642         resources[0].start = base;
643         resources[0].end = base + size - 1;
644 
645         resources[1].flags = IORESOURCE_IRQ;
646         resources[1].start = resources[1].end = irq;
647 
648         if (!vm_cmdline_parent_registered) {
649                 err = device_register(&vm_cmdline_parent);
650                 if (err) {
651                         pr_err("Failed to register parent device!\n");
652                         return err;
653                 }
654                 vm_cmdline_parent_registered = 1;
655         }
656 
657         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
658                        vm_cmdline_id,
659                        (unsigned long long)resources[0].start,
660                        (unsigned long long)resources[0].end,
661                        (int)resources[1].start);
662 
663         pdev = platform_device_register_resndata(&vm_cmdline_parent,
664                         "virtio-mmio", vm_cmdline_id++,
665                         resources, ARRAY_SIZE(resources), NULL, 0);
666         if (IS_ERR(pdev))
667                 return PTR_ERR(pdev);
668 
669         return 0;
670 }
671 
672 static int vm_cmdline_get_device(struct device *dev, void *data)
673 {
674         char *buffer = data;
675         unsigned int len = strlen(buffer);
676         struct platform_device *pdev = to_platform_device(dev);
677 
678         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
679                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
680                         (unsigned long long)pdev->resource[0].start,
681                         (unsigned long long)pdev->resource[1].start,
682                         pdev->id);
683         return 0;
684 }
685 
686 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
687 {
688         buffer[0] = '\0';
689         device_for_each_child(&vm_cmdline_parent, buffer,
690                         vm_cmdline_get_device);
691         return strlen(buffer) + 1;
692 }
693 
694 static const struct kernel_param_ops vm_cmdline_param_ops = {
695         .set = vm_cmdline_set,
696         .get = vm_cmdline_get,
697 };
698 
699 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
700 
701 static int vm_unregister_cmdline_device(struct device *dev,
702                 void *data)
703 {
704         platform_device_unregister(to_platform_device(dev));
705 
706         return 0;
707 }
708 
709 static void vm_unregister_cmdline_devices(void)
710 {
711         if (vm_cmdline_parent_registered) {
712                 device_for_each_child(&vm_cmdline_parent, NULL,
713                                 vm_unregister_cmdline_device);
714                 device_unregister(&vm_cmdline_parent);
715                 vm_cmdline_parent_registered = 0;
716         }
717 }
718 
719 #else
720 
721 static void vm_unregister_cmdline_devices(void)
722 {
723 }
724 
725 #endif
726 
727 /* Platform driver */
728 
729 static struct of_device_id virtio_mmio_match[] = {
730         { .compatible = "virtio,mmio", },
731         {},
732 };
733 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
734 
735 static struct platform_driver virtio_mmio_driver = {
736         .probe          = virtio_mmio_probe,
737         .remove         = virtio_mmio_remove,
738         .driver         = {
739                 .name   = "virtio-mmio",
740                 .of_match_table = virtio_mmio_match,
741         },
742 };
743 
744 static int __init virtio_mmio_init(void)
745 {
746         return platform_driver_register(&virtio_mmio_driver);
747 }
748 
749 static void __exit virtio_mmio_exit(void)
750 {
751         platform_driver_unregister(&virtio_mmio_driver);
752         vm_unregister_cmdline_devices();
753 }
754 
755 module_init(virtio_mmio_init);
756 module_exit(virtio_mmio_exit);
757 
758 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
759 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
760 MODULE_LICENSE("GPL");
761 

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