Version:  2.0.40 2.2.26 2.4.37 3.13 3.14 3.15 3.16 3.17 3.18 3.19 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 4.9 4.10

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/acpi.h>
 62 #include <linux/dma-mapping.h>
 63 #include <linux/highmem.h>
 64 #include <linux/interrupt.h>
 65 #include <linux/io.h>
 66 #include <linux/list.h>
 67 #include <linux/module.h>
 68 #include <linux/platform_device.h>
 69 #include <linux/slab.h>
 70 #include <linux/spinlock.h>
 71 #include <linux/virtio.h>
 72 #include <linux/virtio_config.h>
 73 #include <linux/virtio_mmio.h>
 74 #include <linux/virtio_ring.h>
 75 
 76 
 77 
 78 /* The alignment to use between consumer and producer parts of vring.
 79  * Currently hardcoded to the page size. */
 80 #define VIRTIO_MMIO_VRING_ALIGN         PAGE_SIZE
 81 
 82 
 83 
 84 #define to_virtio_mmio_device(_plat_dev) \
 85         container_of(_plat_dev, struct virtio_mmio_device, vdev)
 86 
 87 struct virtio_mmio_device {
 88         struct virtio_device vdev;
 89         struct platform_device *pdev;
 90 
 91         void __iomem *base;
 92         unsigned long version;
 93 
 94         /* a list of queues so we can dispatch IRQs */
 95         spinlock_t lock;
 96         struct list_head virtqueues;
 97 };
 98 
 99 struct virtio_mmio_vq_info {
100         /* the actual virtqueue */
101         struct virtqueue *vq;
102 
103         /* the list node for the virtqueues list */
104         struct list_head node;
105 };
106 
107 
108 
109 /* Configuration interface */
110 
111 static u64 vm_get_features(struct virtio_device *vdev)
112 {
113         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
114         u64 features;
115 
116         writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
117         features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
118         features <<= 32;
119 
120         writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
121         features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
122 
123         return features;
124 }
125 
126 static int vm_finalize_features(struct virtio_device *vdev)
127 {
128         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
129 
130         /* Give virtio_ring a chance to accept features. */
131         vring_transport_features(vdev);
132 
133         /* Make sure there is are no mixed devices */
134         if (vm_dev->version == 2 &&
135                         !__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
136                 dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
137                 return -EINVAL;
138         }
139 
140         writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
141         writel((u32)(vdev->features >> 32),
142                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
143 
144         writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
145         writel((u32)vdev->features,
146                         vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
147 
148         return 0;
149 }
150 
151 static void vm_get(struct virtio_device *vdev, unsigned offset,
152                    void *buf, unsigned len)
153 {
154         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
155         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
156         u8 b;
157         __le16 w;
158         __le32 l;
159 
160         if (vm_dev->version == 1) {
161                 u8 *ptr = buf;
162                 int i;
163 
164                 for (i = 0; i < len; i++)
165                         ptr[i] = readb(base + offset + i);
166                 return;
167         }
168 
169         switch (len) {
170         case 1:
171                 b = readb(base + offset);
172                 memcpy(buf, &b, sizeof b);
173                 break;
174         case 2:
175                 w = cpu_to_le16(readw(base + offset));
176                 memcpy(buf, &w, sizeof w);
177                 break;
178         case 4:
179                 l = cpu_to_le32(readl(base + offset));
180                 memcpy(buf, &l, sizeof l);
181                 break;
182         case 8:
183                 l = cpu_to_le32(readl(base + offset));
184                 memcpy(buf, &l, sizeof l);
185                 l = cpu_to_le32(ioread32(base + offset + sizeof l));
186                 memcpy(buf + sizeof l, &l, sizeof l);
187                 break;
188         default:
189                 BUG();
190         }
191 }
192 
193 static void vm_set(struct virtio_device *vdev, unsigned offset,
194                    const void *buf, unsigned len)
195 {
196         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
197         void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
198         u8 b;
199         __le16 w;
200         __le32 l;
201 
202         if (vm_dev->version == 1) {
203                 const u8 *ptr = buf;
204                 int i;
205 
206                 for (i = 0; i < len; i++)
207                         writeb(ptr[i], base + offset + i);
208 
209                 return;
210         }
211 
212         switch (len) {
213         case 1:
214                 memcpy(&b, buf, sizeof b);
215                 writeb(b, base + offset);
216                 break;
217         case 2:
218                 memcpy(&w, buf, sizeof w);
219                 writew(le16_to_cpu(w), base + offset);
220                 break;
221         case 4:
222                 memcpy(&l, buf, sizeof l);
223                 writel(le32_to_cpu(l), base + offset);
224                 break;
225         case 8:
226                 memcpy(&l, buf, sizeof l);
227                 writel(le32_to_cpu(l), base + offset);
228                 memcpy(&l, buf + sizeof l, sizeof l);
229                 writel(le32_to_cpu(l), base + offset + sizeof l);
230                 break;
231         default:
232                 BUG();
233         }
234 }
235 
236 static u32 vm_generation(struct virtio_device *vdev)
237 {
238         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
239 
240         if (vm_dev->version == 1)
241                 return 0;
242         else
243                 return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
244 }
245 
246 static u8 vm_get_status(struct virtio_device *vdev)
247 {
248         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
249 
250         return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
251 }
252 
253 static void vm_set_status(struct virtio_device *vdev, u8 status)
254 {
255         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
256 
257         /* We should never be setting status to 0. */
258         BUG_ON(status == 0);
259 
260         writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
261 }
262 
263 static void vm_reset(struct virtio_device *vdev)
264 {
265         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
266 
267         /* 0 status means a reset. */
268         writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
269 }
270 
271 
272 
273 /* Transport interface */
274 
275 /* the notify function used when creating a virt queue */
276 static bool vm_notify(struct virtqueue *vq)
277 {
278         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
279 
280         /* We write the queue's selector into the notification register to
281          * signal the other end */
282         writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
283         return true;
284 }
285 
286 /* Notify all virtqueues on an interrupt. */
287 static irqreturn_t vm_interrupt(int irq, void *opaque)
288 {
289         struct virtio_mmio_device *vm_dev = opaque;
290         struct virtio_mmio_vq_info *info;
291         unsigned long status;
292         unsigned long flags;
293         irqreturn_t ret = IRQ_NONE;
294 
295         /* Read and acknowledge interrupts */
296         status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
297         writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
298 
299         if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
300                 virtio_config_changed(&vm_dev->vdev);
301                 ret = IRQ_HANDLED;
302         }
303 
304         if (likely(status & VIRTIO_MMIO_INT_VRING)) {
305                 spin_lock_irqsave(&vm_dev->lock, flags);
306                 list_for_each_entry(info, &vm_dev->virtqueues, node)
307                         ret |= vring_interrupt(irq, info->vq);
308                 spin_unlock_irqrestore(&vm_dev->lock, flags);
309         }
310 
311         return ret;
312 }
313 
314 
315 
316 static void vm_del_vq(struct virtqueue *vq)
317 {
318         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
319         struct virtio_mmio_vq_info *info = vq->priv;
320         unsigned long flags;
321         unsigned int index = vq->index;
322 
323         spin_lock_irqsave(&vm_dev->lock, flags);
324         list_del(&info->node);
325         spin_unlock_irqrestore(&vm_dev->lock, flags);
326 
327         /* Select and deactivate the queue */
328         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
329         if (vm_dev->version == 1) {
330                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
331         } else {
332                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
333                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
334         }
335 
336         vring_del_virtqueue(vq);
337 
338         kfree(info);
339 }
340 
341 static void vm_del_vqs(struct virtio_device *vdev)
342 {
343         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
344         struct virtqueue *vq, *n;
345 
346         list_for_each_entry_safe(vq, n, &vdev->vqs, list)
347                 vm_del_vq(vq);
348 
349         free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
350 }
351 
352 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
353                                   void (*callback)(struct virtqueue *vq),
354                                   const char *name)
355 {
356         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
357         struct virtio_mmio_vq_info *info;
358         struct virtqueue *vq;
359         unsigned long flags;
360         unsigned int num;
361         int err;
362 
363         if (!name)
364                 return NULL;
365 
366         /* Select the queue we're interested in */
367         writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
368 
369         /* Queue shouldn't already be set up. */
370         if (readl(vm_dev->base + (vm_dev->version == 1 ?
371                         VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
372                 err = -ENOENT;
373                 goto error_available;
374         }
375 
376         /* Allocate and fill out our active queue description */
377         info = kmalloc(sizeof(*info), GFP_KERNEL);
378         if (!info) {
379                 err = -ENOMEM;
380                 goto error_kmalloc;
381         }
382 
383         num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
384         if (num == 0) {
385                 err = -ENOENT;
386                 goto error_new_virtqueue;
387         }
388 
389         /* Create the vring */
390         vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
391                                  true, true, vm_notify, callback, name);
392         if (!vq) {
393                 err = -ENOMEM;
394                 goto error_new_virtqueue;
395         }
396 
397         /* Activate the queue */
398         writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
399         if (vm_dev->version == 1) {
400                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
401                 writel(virtqueue_get_desc_addr(vq) >> PAGE_SHIFT,
402                                 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
403         } else {
404                 u64 addr;
405 
406                 addr = virtqueue_get_desc_addr(vq);
407                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
408                 writel((u32)(addr >> 32),
409                                 vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
410 
411                 addr = virtqueue_get_avail_addr(vq);
412                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
413                 writel((u32)(addr >> 32),
414                                 vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
415 
416                 addr = virtqueue_get_used_addr(vq);
417                 writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
418                 writel((u32)(addr >> 32),
419                                 vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
420 
421                 writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
422         }
423 
424         vq->priv = info;
425         info->vq = vq;
426 
427         spin_lock_irqsave(&vm_dev->lock, flags);
428         list_add(&info->node, &vm_dev->virtqueues);
429         spin_unlock_irqrestore(&vm_dev->lock, flags);
430 
431         return vq;
432 
433 error_new_virtqueue:
434         if (vm_dev->version == 1) {
435                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
436         } else {
437                 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
438                 WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
439         }
440         kfree(info);
441 error_kmalloc:
442 error_available:
443         return ERR_PTR(err);
444 }
445 
446 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
447                        struct virtqueue *vqs[],
448                        vq_callback_t *callbacks[],
449                        const char * const names[])
450 {
451         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
452         unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
453         int i, err;
454 
455         err = request_irq(irq, vm_interrupt, IRQF_SHARED,
456                         dev_name(&vdev->dev), vm_dev);
457         if (err)
458                 return err;
459 
460         for (i = 0; i < nvqs; ++i) {
461                 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
462                 if (IS_ERR(vqs[i])) {
463                         vm_del_vqs(vdev);
464                         return PTR_ERR(vqs[i]);
465                 }
466         }
467 
468         return 0;
469 }
470 
471 static const char *vm_bus_name(struct virtio_device *vdev)
472 {
473         struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
474 
475         return vm_dev->pdev->name;
476 }
477 
478 static const struct virtio_config_ops virtio_mmio_config_ops = {
479         .get            = vm_get,
480         .set            = vm_set,
481         .generation     = vm_generation,
482         .get_status     = vm_get_status,
483         .set_status     = vm_set_status,
484         .reset          = vm_reset,
485         .find_vqs       = vm_find_vqs,
486         .del_vqs        = vm_del_vqs,
487         .get_features   = vm_get_features,
488         .finalize_features = vm_finalize_features,
489         .bus_name       = vm_bus_name,
490 };
491 
492 
493 static void virtio_mmio_release_dev_empty(struct device *_d) {}
494 
495 /* Platform device */
496 
497 static int virtio_mmio_probe(struct platform_device *pdev)
498 {
499         struct virtio_mmio_device *vm_dev;
500         struct resource *mem;
501         unsigned long magic;
502         int rc;
503 
504         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
505         if (!mem)
506                 return -EINVAL;
507 
508         if (!devm_request_mem_region(&pdev->dev, mem->start,
509                         resource_size(mem), pdev->name))
510                 return -EBUSY;
511 
512         vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
513         if (!vm_dev)
514                 return  -ENOMEM;
515 
516         vm_dev->vdev.dev.parent = &pdev->dev;
517         vm_dev->vdev.dev.release = virtio_mmio_release_dev_empty;
518         vm_dev->vdev.config = &virtio_mmio_config_ops;
519         vm_dev->pdev = pdev;
520         INIT_LIST_HEAD(&vm_dev->virtqueues);
521         spin_lock_init(&vm_dev->lock);
522 
523         vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
524         if (vm_dev->base == NULL)
525                 return -EFAULT;
526 
527         /* Check magic value */
528         magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
529         if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
530                 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
531                 return -ENODEV;
532         }
533 
534         /* Check device version */
535         vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
536         if (vm_dev->version < 1 || vm_dev->version > 2) {
537                 dev_err(&pdev->dev, "Version %ld not supported!\n",
538                                 vm_dev->version);
539                 return -ENXIO;
540         }
541 
542         vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
543         if (vm_dev->vdev.id.device == 0) {
544                 /*
545                  * virtio-mmio device with an ID 0 is a (dummy) placeholder
546                  * with no function. End probing now with no error reported.
547                  */
548                 return -ENODEV;
549         }
550         vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
551 
552         if (vm_dev->version == 1) {
553                 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
554 
555                 rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
556                 /*
557                  * In the legacy case, ensure our coherently-allocated virtio
558                  * ring will be at an address expressable as a 32-bit PFN.
559                  */
560                 if (!rc)
561                         dma_set_coherent_mask(&pdev->dev,
562                                               DMA_BIT_MASK(32 + PAGE_SHIFT));
563         } else {
564                 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
565         }
566         if (rc)
567                 rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
568         if (rc)
569                 dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
570 
571         platform_set_drvdata(pdev, vm_dev);
572 
573         return register_virtio_device(&vm_dev->vdev);
574 }
575 
576 static int virtio_mmio_remove(struct platform_device *pdev)
577 {
578         struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
579 
580         unregister_virtio_device(&vm_dev->vdev);
581 
582         return 0;
583 }
584 
585 
586 
587 /* Devices list parameter */
588 
589 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
590 
591 static struct device vm_cmdline_parent = {
592         .init_name = "virtio-mmio-cmdline",
593 };
594 
595 static int vm_cmdline_parent_registered;
596 static int vm_cmdline_id;
597 
598 static int vm_cmdline_set(const char *device,
599                 const struct kernel_param *kp)
600 {
601         int err;
602         struct resource resources[2] = {};
603         char *str;
604         long long int base, size;
605         unsigned int irq;
606         int processed, consumed = 0;
607         struct platform_device *pdev;
608 
609         /* Consume "size" part of the command line parameter */
610         size = memparse(device, &str);
611 
612         /* Get "@<base>:<irq>[:<id>]" chunks */
613         processed = sscanf(str, "@%lli:%u%n:%d%n",
614                         &base, &irq, &consumed,
615                         &vm_cmdline_id, &consumed);
616 
617         /*
618          * sscanf() must processes at least 2 chunks; also there
619          * must be no extra characters after the last chunk, so
620          * str[consumed] must be '\0'
621          */
622         if (processed < 2 || str[consumed])
623                 return -EINVAL;
624 
625         resources[0].flags = IORESOURCE_MEM;
626         resources[0].start = base;
627         resources[0].end = base + size - 1;
628 
629         resources[1].flags = IORESOURCE_IRQ;
630         resources[1].start = resources[1].end = irq;
631 
632         if (!vm_cmdline_parent_registered) {
633                 err = device_register(&vm_cmdline_parent);
634                 if (err) {
635                         pr_err("Failed to register parent device!\n");
636                         return err;
637                 }
638                 vm_cmdline_parent_registered = 1;
639         }
640 
641         pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
642                        vm_cmdline_id,
643                        (unsigned long long)resources[0].start,
644                        (unsigned long long)resources[0].end,
645                        (int)resources[1].start);
646 
647         pdev = platform_device_register_resndata(&vm_cmdline_parent,
648                         "virtio-mmio", vm_cmdline_id++,
649                         resources, ARRAY_SIZE(resources), NULL, 0);
650         if (IS_ERR(pdev))
651                 return PTR_ERR(pdev);
652 
653         return 0;
654 }
655 
656 static int vm_cmdline_get_device(struct device *dev, void *data)
657 {
658         char *buffer = data;
659         unsigned int len = strlen(buffer);
660         struct platform_device *pdev = to_platform_device(dev);
661 
662         snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
663                         pdev->resource[0].end - pdev->resource[0].start + 1ULL,
664                         (unsigned long long)pdev->resource[0].start,
665                         (unsigned long long)pdev->resource[1].start,
666                         pdev->id);
667         return 0;
668 }
669 
670 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
671 {
672         buffer[0] = '\0';
673         device_for_each_child(&vm_cmdline_parent, buffer,
674                         vm_cmdline_get_device);
675         return strlen(buffer) + 1;
676 }
677 
678 static const struct kernel_param_ops vm_cmdline_param_ops = {
679         .set = vm_cmdline_set,
680         .get = vm_cmdline_get,
681 };
682 
683 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
684 
685 static int vm_unregister_cmdline_device(struct device *dev,
686                 void *data)
687 {
688         platform_device_unregister(to_platform_device(dev));
689 
690         return 0;
691 }
692 
693 static void vm_unregister_cmdline_devices(void)
694 {
695         if (vm_cmdline_parent_registered) {
696                 device_for_each_child(&vm_cmdline_parent, NULL,
697                                 vm_unregister_cmdline_device);
698                 device_unregister(&vm_cmdline_parent);
699                 vm_cmdline_parent_registered = 0;
700         }
701 }
702 
703 #else
704 
705 static void vm_unregister_cmdline_devices(void)
706 {
707 }
708 
709 #endif
710 
711 /* Platform driver */
712 
713 static struct of_device_id virtio_mmio_match[] = {
714         { .compatible = "virtio,mmio", },
715         {},
716 };
717 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
718 
719 #ifdef CONFIG_ACPI
720 static const struct acpi_device_id virtio_mmio_acpi_match[] = {
721         { "LNRO0005", },
722         { }
723 };
724 MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
725 #endif
726 
727 static struct platform_driver virtio_mmio_driver = {
728         .probe          = virtio_mmio_probe,
729         .remove         = virtio_mmio_remove,
730         .driver         = {
731                 .name   = "virtio-mmio",
732                 .of_match_table = virtio_mmio_match,
733                 .acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
734         },
735 };
736 
737 static int __init virtio_mmio_init(void)
738 {
739         return platform_driver_register(&virtio_mmio_driver);
740 }
741 
742 static void __exit virtio_mmio_exit(void)
743 {
744         platform_driver_unregister(&virtio_mmio_driver);
745         vm_unregister_cmdline_devices();
746 }
747 
748 module_init(virtio_mmio_init);
749 module_exit(virtio_mmio_exit);
750 
751 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
752 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
753 MODULE_LICENSE("GPL");
754 

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