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
85struct 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
97struct 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
115static 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
130static 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
155static 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
197static 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
240static 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
250static 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
257static 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
267static 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 */
280static 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. */
291static 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
320static 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
347static 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
360static 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
466error_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);
474error_alloc_pages:
475	kfree(info);
476error_kmalloc:
477error_available:
478	return ERR_PTR(err);
479}
480
481static 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
506static 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
513static 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
531static 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
592static 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
607static struct device vm_cmdline_parent = {
608	.init_name = "virtio-mmio-cmdline",
609};
610
611static int vm_cmdline_parent_registered;
612static int vm_cmdline_id;
613
614static 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
672static 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
686static 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
694static struct kernel_param_ops vm_cmdline_param_ops = {
695	.set = vm_cmdline_set,
696	.get = vm_cmdline_get,
697};
698
699device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
700
701static 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
709static 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
721static void vm_unregister_cmdline_devices(void)
722{
723}
724
725#endif
726
727/* Platform driver */
728
729static struct of_device_id virtio_mmio_match[] = {
730	{ .compatible = "virtio,mmio", },
731	{},
732};
733MODULE_DEVICE_TABLE(of, virtio_mmio_match);
734
735static 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
744static int __init virtio_mmio_init(void)
745{
746	return platform_driver_register(&virtio_mmio_driver);
747}
748
749static void __exit virtio_mmio_exit(void)
750{
751	platform_driver_unregister(&virtio_mmio_driver);
752	vm_unregister_cmdline_devices();
753}
754
755module_init(virtio_mmio_init);
756module_exit(virtio_mmio_exit);
757
758MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
759MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
760MODULE_LICENSE("GPL");
761