virtio_mmio.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Virtio memory mapped device driver
  4 *
  5 * Copyright 2011-2014, ARM Ltd.
  6 *
  7 * This module allows virtio devices to be used over a virtual, memory mapped
  8 * platform device.
  9 *
 10 * The guest device(s) may be instantiated in one of three equivalent ways:
 11 *
 12 * 1. Static platform device in board's code, eg.:
 13 *
 14 *	static struct platform_device v2m_virtio_device = {
 15 *		.name = "virtio-mmio",
 16 *		.id = -1,
 17 *		.num_resources = 2,
 18 *		.resource = (struct resource []) {
 19 *			{
 20 *				.start = 0x1001e000,
 21 *				.end = 0x1001e0ff,
 22 *				.flags = IORESOURCE_MEM,
 23 *			}, {
 24 *				.start = 42 + 32,
 25 *				.end = 42 + 32,
 26 *				.flags = IORESOURCE_IRQ,
 27 *			},
 28 *		}
 29 *	};
 30 *
 31 * 2. Device Tree node, eg.:
 32 *
 33 *		virtio_block@1e000 {
 34 *			compatible = "virtio,mmio";
 35 *			reg = <0x1e000 0x100>;
 36 *			interrupts = <42>;
 37 *		}
 38 *
 39 * 3. Kernel module (or command line) parameter. Can be used more than once -
 40 *    one device will be created for each one. Syntax:
 41 *
 42 *		[virtio_mmio.]device=<size>@<baseaddr>:<irq>[:<id>]
 43 *    where:
 44 *		<size>     := size (can use standard suffixes like K, M or G)
 45 *		<baseaddr> := physical base address
 46 *		<irq>      := interrupt number (as passed to request_irq())
 47 *		<id>       := (optional) platform device id
 48 *    eg.:
 49 *		virtio_mmio.device=0x100@0x100b0000:48 \
 50 *				virtio_mmio.device=1K@0x1001e000:74
 51 *
 52 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
 53 */
 54
 55#define pr_fmt(fmt) "virtio-mmio: " fmt
 56
 57#include <linux/acpi.h>
 58#include <linux/dma-mapping.h>
 59#include <linux/highmem.h>
 60#include <linux/interrupt.h>
 61#include <linux/io.h>
 62#include <linux/list.h>
 63#include <linux/module.h>
 64#include <linux/of.h>
 65#include <linux/platform_device.h>
 66#include <linux/pm.h>
 67#include <linux/slab.h>
 68#include <linux/virtio.h>
 69#include <linux/virtio_config.h>
 70#include <uapi/linux/virtio_mmio.h>
 71#include <linux/virtio_ring.h>
 72
 73
 74
 75/* The alignment to use between consumer and producer parts of vring.
 76 * Currently hardcoded to the page size. */
 77#define VIRTIO_MMIO_VRING_ALIGN		PAGE_SIZE
 78
 79
 80
 81#define to_virtio_mmio_device(_plat_dev) \
 82	container_of(_plat_dev, struct virtio_mmio_device, vdev)
 83
 84struct virtio_mmio_device {
 85	struct virtio_device vdev;
 86	struct platform_device *pdev;
 87
 88	void __iomem *base;
 89	unsigned long version;
 90};
 91
 92/* Configuration interface */
 93
 94static u64 vm_get_features(struct virtio_device *vdev)
 95{
 96	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
 97	u64 features;
 98
 99	writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
100	features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
101	features <<= 32;
102
103	writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
104	features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
105
106	return features;
107}
108
109static int vm_finalize_features(struct virtio_device *vdev)
110{
111	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
112
113	/* Give virtio_ring a chance to accept features. */
114	vring_transport_features(vdev);
115
116	/* Make sure there are no mixed devices */
117	if (vm_dev->version == 2 &&
118			!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
119		dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
120		return -EINVAL;
121	}
122
123	writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
124	writel((u32)(vdev->features >> 32),
125			vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
126
127	writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
128	writel((u32)vdev->features,
129			vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
130
131	return 0;
132}
133
134static void vm_get(struct virtio_device *vdev, unsigned int offset,
135		   void *buf, unsigned int len)
136{
137	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
138	void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
139	u8 b;
140	__le16 w;
141	__le32 l;
142
143	if (vm_dev->version == 1) {
144		u8 *ptr = buf;
145		int i;
146
147		for (i = 0; i < len; i++)
148			ptr[i] = readb(base + offset + i);
149		return;
150	}
151
152	switch (len) {
153	case 1:
154		b = readb(base + offset);
155		memcpy(buf, &b, sizeof b);
156		break;
157	case 2:
158		w = cpu_to_le16(readw(base + offset));
159		memcpy(buf, &w, sizeof w);
160		break;
161	case 4:
162		l = cpu_to_le32(readl(base + offset));
163		memcpy(buf, &l, sizeof l);
164		break;
165	case 8:
166		l = cpu_to_le32(readl(base + offset));
167		memcpy(buf, &l, sizeof l);
168		l = cpu_to_le32(ioread32(base + offset + sizeof l));
169		memcpy(buf + sizeof l, &l, sizeof l);
170		break;
171	default:
172		BUG();
173	}
174}
175
176static void vm_set(struct virtio_device *vdev, unsigned int offset,
177		   const void *buf, unsigned int len)
178{
179	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
180	void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
181	u8 b;
182	__le16 w;
183	__le32 l;
184
185	if (vm_dev->version == 1) {
186		const u8 *ptr = buf;
187		int i;
188
189		for (i = 0; i < len; i++)
190			writeb(ptr[i], base + offset + i);
191
192		return;
193	}
194
195	switch (len) {
196	case 1:
197		memcpy(&b, buf, sizeof b);
198		writeb(b, base + offset);
199		break;
200	case 2:
201		memcpy(&w, buf, sizeof w);
202		writew(le16_to_cpu(w), base + offset);
203		break;
204	case 4:
205		memcpy(&l, buf, sizeof l);
206		writel(le32_to_cpu(l), base + offset);
207		break;
208	case 8:
209		memcpy(&l, buf, sizeof l);
210		writel(le32_to_cpu(l), base + offset);
211		memcpy(&l, buf + sizeof l, sizeof l);
212		writel(le32_to_cpu(l), base + offset + sizeof l);
213		break;
214	default:
215		BUG();
216	}
217}
218
219static u32 vm_generation(struct virtio_device *vdev)
220{
221	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
222
223	if (vm_dev->version == 1)
224		return 0;
225	else
226		return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
227}
228
229static u8 vm_get_status(struct virtio_device *vdev)
230{
231	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
232
233	return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
234}
235
236static void vm_set_status(struct virtio_device *vdev, u8 status)
237{
238	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
239
240	/* We should never be setting status to 0. */
241	BUG_ON(status == 0);
242
243	/*
244	 * Per memory-barriers.txt, wmb() is not needed to guarantee
245	 * that the cache coherent memory writes have completed
246	 * before writing to the MMIO region.
247	 */
248	writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
249}
250
251static void vm_reset(struct virtio_device *vdev)
252{
253	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
254
255	/* 0 status means a reset. */
256	writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
257}
258
259
260
261/* Transport interface */
262
263/* the notify function used when creating a virt queue */
264static bool vm_notify(struct virtqueue *vq)
265{
266	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
267
268	/* We write the queue's selector into the notification register to
269	 * signal the other end */
270	writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
271	return true;
272}
273
274static bool vm_notify_with_data(struct virtqueue *vq)
275{
276	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
277	u32 data = vring_notification_data(vq);
278
279	writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
280
281	return true;
282}
283
284/* Notify all virtqueues on an interrupt. */
285static irqreturn_t vm_interrupt(int irq, void *opaque)
286{
287	struct virtio_mmio_device *vm_dev = opaque;
288	struct virtqueue *vq;
289	unsigned long status;
290	irqreturn_t ret = IRQ_NONE;
291
292	/* Read and acknowledge interrupts */
293	status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
294	writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
295
296	if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
297		virtio_config_changed(&vm_dev->vdev);
298		ret = IRQ_HANDLED;
299	}
300
301	if (likely(status & VIRTIO_MMIO_INT_VRING)) {
302		virtio_device_for_each_vq(&vm_dev->vdev, vq)
303			ret |= vring_interrupt(irq, vq);
304	}
305
306	return ret;
307}
308
309
310
311static void vm_del_vq(struct virtqueue *vq)
312{
313	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
314	unsigned int index = vq->index;
315
316	/* Select and deactivate the queue */
317	writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
318	if (vm_dev->version == 1) {
319		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
320	} else {
321		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
322		WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
323	}
324
325	vring_del_virtqueue(vq);
326}
327
328static void vm_del_vqs(struct virtio_device *vdev)
329{
330	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
331	struct virtqueue *vq, *n;
332
333	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
334		vm_del_vq(vq);
335
336	free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
337}
338
339static void vm_synchronize_cbs(struct virtio_device *vdev)
340{
341	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
342
343	synchronize_irq(platform_get_irq(vm_dev->pdev, 0));
344}
345
346static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int index,
347				  void (*callback)(struct virtqueue *vq),
348				  const char *name, bool ctx)
349{
350	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
351	bool (*notify)(struct virtqueue *vq);
352	struct virtqueue *vq;
353	unsigned int num;
354	int err;
355
356	if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
357		notify = vm_notify_with_data;
358	else
359		notify = vm_notify;
360
361	if (!name)
362		return NULL;
363
364	/* Select the queue we're interested in */
365	writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
366
367	/* Queue shouldn't already be set up. */
368	if (readl(vm_dev->base + (vm_dev->version == 1 ?
369			VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
370		err = -ENOENT;
371		goto error_available;
372	}
373
374	num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
375	if (num == 0) {
376		err = -ENOENT;
377		goto error_new_virtqueue;
378	}
379
380	/* Create the vring */
381	vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
382				 true, true, ctx, notify, callback, name);
383	if (!vq) {
384		err = -ENOMEM;
385		goto error_new_virtqueue;
386	}
387
388	vq->num_max = num;
389
390	/* Activate the queue */
391	writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
392	if (vm_dev->version == 1) {
393		u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT;
394
395		/*
396		 * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
397		 * that doesn't fit in 32bit, fail the setup rather than
398		 * pretending to be successful.
399		 */
400		if (q_pfn >> 32) {
401			dev_err(&vdev->dev,
402				"platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
403				0x1ULL << (32 + PAGE_SHIFT - 30));
404			err = -E2BIG;
405			goto error_bad_pfn;
406		}
407
408		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
409		writel(q_pfn, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
410	} else {
411		u64 addr;
412
413		addr = virtqueue_get_desc_addr(vq);
414		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
415		writel((u32)(addr >> 32),
416				vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
417
418		addr = virtqueue_get_avail_addr(vq);
419		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
420		writel((u32)(addr >> 32),
421				vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
422
423		addr = virtqueue_get_used_addr(vq);
424		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
425		writel((u32)(addr >> 32),
426				vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
427
428		writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
429	}
430
431	return vq;
432
433error_bad_pfn:
434	vring_del_virtqueue(vq);
435error_new_virtqueue:
436	if (vm_dev->version == 1) {
437		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
438	} else {
439		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
440		WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
441	}
442error_available:
443	return ERR_PTR(err);
444}
445
446static int vm_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
447		       struct virtqueue *vqs[],
448		       struct virtqueue_info vqs_info[],
449		       struct irq_affinity *desc)
450{
451	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
452	int irq = platform_get_irq(vm_dev->pdev, 0);
453	int i, err, queue_idx = 0;
454
455	if (irq < 0)
456		return irq;
457
458	err = request_irq(irq, vm_interrupt, IRQF_SHARED,
459			dev_name(&vdev->dev), vm_dev);
460	if (err)
461		return err;
462
463	if (of_property_read_bool(vm_dev->pdev->dev.of_node, "wakeup-source"))
464		enable_irq_wake(irq);
465
466	for (i = 0; i < nvqs; ++i) {
467		struct virtqueue_info *vqi = &vqs_info[i];
468
469		if (!vqi->name) {
470			vqs[i] = NULL;
471			continue;
472		}
473
474		vqs[i] = vm_setup_vq(vdev, queue_idx++, vqi->callback,
475				     vqi->name, vqi->ctx);
476		if (IS_ERR(vqs[i])) {
477			vm_del_vqs(vdev);
478			return PTR_ERR(vqs[i]);
479		}
480	}
481
482	return 0;
483}
484
485static const char *vm_bus_name(struct virtio_device *vdev)
486{
487	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
488
489	return vm_dev->pdev->name;
490}
491
492static bool vm_get_shm_region(struct virtio_device *vdev,
493			      struct virtio_shm_region *region, u8 id)
494{
495	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
496	u64 len, addr;
497
498	/* Select the region we're interested in */
499	writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
500
501	/* Read the region size */
502	len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
503	len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
504
505	region->len = len;
506
507	/* Check if region length is -1. If that's the case, the shared memory
508	 * region does not exist and there is no need to proceed further.
509	 */
510	if (len == ~(u64)0)
511		return false;
512
513	/* Read the region base address */
514	addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
515	addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
516
517	region->addr = addr;
518
519	return true;
520}
521
522static const struct virtio_config_ops virtio_mmio_config_ops = {
523	.get		= vm_get,
524	.set		= vm_set,
525	.generation	= vm_generation,
526	.get_status	= vm_get_status,
527	.set_status	= vm_set_status,
528	.reset		= vm_reset,
529	.find_vqs	= vm_find_vqs,
530	.del_vqs	= vm_del_vqs,
531	.get_features	= vm_get_features,
532	.finalize_features = vm_finalize_features,
533	.bus_name	= vm_bus_name,
534	.get_shm_region = vm_get_shm_region,
535	.synchronize_cbs = vm_synchronize_cbs,
536};
537
538#ifdef CONFIG_PM_SLEEP
539static int virtio_mmio_freeze(struct device *dev)
540{
541	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
542
543	return virtio_device_freeze(&vm_dev->vdev);
544}
545
546static int virtio_mmio_restore(struct device *dev)
547{
548	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
549
550	if (vm_dev->version == 1)
551		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
552
553	return virtio_device_restore(&vm_dev->vdev);
554}
555
556static const struct dev_pm_ops virtio_mmio_pm_ops = {
557	SET_SYSTEM_SLEEP_PM_OPS(virtio_mmio_freeze, virtio_mmio_restore)
558};
559#endif
560
561static void virtio_mmio_release_dev(struct device *_d)
562{
563	struct virtio_device *vdev =
564			container_of(_d, struct virtio_device, dev);
565	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
566
567	kfree(vm_dev);
568}
569
570/* Platform device */
571
572static int virtio_mmio_probe(struct platform_device *pdev)
573{
574	struct virtio_mmio_device *vm_dev;
575	unsigned long magic;
576	int rc;
577
578	vm_dev = kzalloc(sizeof(*vm_dev), GFP_KERNEL);
579	if (!vm_dev)
580		return -ENOMEM;
581
582	vm_dev->vdev.dev.parent = &pdev->dev;
583	vm_dev->vdev.dev.release = virtio_mmio_release_dev;
584	vm_dev->vdev.config = &virtio_mmio_config_ops;
585	vm_dev->pdev = pdev;
586
587	vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
588	if (IS_ERR(vm_dev->base)) {
589		rc = PTR_ERR(vm_dev->base);
590		goto free_vm_dev;
591	}
592
593	/* Check magic value */
594	magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
595	if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
596		dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
597		rc = -ENODEV;
598		goto free_vm_dev;
599	}
600
601	/* Check device version */
602	vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
603	if (vm_dev->version < 1 || vm_dev->version > 2) {
604		dev_err(&pdev->dev, "Version %ld not supported!\n",
605				vm_dev->version);
606		rc = -ENXIO;
607		goto free_vm_dev;
608	}
609
610	vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
611	if (vm_dev->vdev.id.device == 0) {
612		/*
613		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
614		 * with no function. End probing now with no error reported.
615		 */
616		rc = -ENODEV;
617		goto free_vm_dev;
618	}
619	vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
620
621	if (vm_dev->version == 1) {
622		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
623
624		rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
625		/*
626		 * In the legacy case, ensure our coherently-allocated virtio
627		 * ring will be at an address expressable as a 32-bit PFN.
628		 */
629		if (!rc)
630			dma_set_coherent_mask(&pdev->dev,
631					      DMA_BIT_MASK(32 + PAGE_SHIFT));
632	} else {
633		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
634	}
635	if (rc)
636		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
637	if (rc)
638		dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
639
640	platform_set_drvdata(pdev, vm_dev);
641
642	rc = register_virtio_device(&vm_dev->vdev);
643	if (rc)
644		put_device(&vm_dev->vdev.dev);
645
646	return rc;
647
648free_vm_dev:
649	kfree(vm_dev);
650	return rc;
651}
652
653static void virtio_mmio_remove(struct platform_device *pdev)
654{
655	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
656	unregister_virtio_device(&vm_dev->vdev);
657}
658
659
660
661/* Devices list parameter */
662
663#if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
664
665static struct device vm_cmdline_parent = {
666	.init_name = "virtio-mmio-cmdline",
667};
668
669static int vm_cmdline_parent_registered;
670static int vm_cmdline_id;
671
672static int vm_cmdline_set(const char *device,
673		const struct kernel_param *kp)
674{
675	int err;
676	struct resource resources[2] = {};
677	char *str;
678	long long base, size;
679	unsigned int irq;
680	int processed, consumed = 0;
681	struct platform_device *pdev;
682
683	/* Consume "size" part of the command line parameter */
684	size = memparse(device, &str);
685
686	/* Get "@<base>:<irq>[:<id>]" chunks */
687	processed = sscanf(str, "@%lli:%u%n:%d%n",
688			&base, &irq, &consumed,
689			&vm_cmdline_id, &consumed);
690
691	/*
692	 * sscanf() must process at least 2 chunks; also there
693	 * must be no extra characters after the last chunk, so
694	 * str[consumed] must be '\0'
695	 */
696	if (processed < 2 || str[consumed] || irq == 0)
697		return -EINVAL;
698
699	resources[0].flags = IORESOURCE_MEM;
700	resources[0].start = base;
701	resources[0].end = base + size - 1;
702
703	resources[1].flags = IORESOURCE_IRQ;
704	resources[1].start = resources[1].end = irq;
705
706	if (!vm_cmdline_parent_registered) {
707		err = device_register(&vm_cmdline_parent);
708		if (err) {
709			put_device(&vm_cmdline_parent);
710			pr_err("Failed to register parent device!\n");
711			return err;
712		}
713		vm_cmdline_parent_registered = 1;
714	}
715
716	pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
717		       vm_cmdline_id,
718		       (unsigned long long)resources[0].start,
719		       (unsigned long long)resources[0].end,
720		       (int)resources[1].start);
721
722	pdev = platform_device_register_resndata(&vm_cmdline_parent,
723			"virtio-mmio", vm_cmdline_id++,
724			resources, ARRAY_SIZE(resources), NULL, 0);
725
726	return PTR_ERR_OR_ZERO(pdev);
727}
728
729static int vm_cmdline_get_device(struct device *dev, void *data)
730{
731	char *buffer = data;
732	unsigned int len = strlen(buffer);
733	struct platform_device *pdev = to_platform_device(dev);
734
735	snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
736			pdev->resource[0].end - pdev->resource[0].start + 1ULL,
737			(unsigned long long)pdev->resource[0].start,
738			(unsigned long long)pdev->resource[1].start,
739			pdev->id);
740	return 0;
741}
742
743static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
744{
745	buffer[0] = '\0';
746	device_for_each_child(&vm_cmdline_parent, buffer,
747			vm_cmdline_get_device);
748	return strlen(buffer) + 1;
749}
750
751static const struct kernel_param_ops vm_cmdline_param_ops = {
752	.set = vm_cmdline_set,
753	.get = vm_cmdline_get,
754};
755
756device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
757
758static int vm_unregister_cmdline_device(struct device *dev,
759		void *data)
760{
761	platform_device_unregister(to_platform_device(dev));
762
763	return 0;
764}
765
766static void vm_unregister_cmdline_devices(void)
767{
768	if (vm_cmdline_parent_registered) {
769		device_for_each_child(&vm_cmdline_parent, NULL,
770				vm_unregister_cmdline_device);
771		device_unregister(&vm_cmdline_parent);
772		vm_cmdline_parent_registered = 0;
773	}
774}
775
776#else
777
778static void vm_unregister_cmdline_devices(void)
779{
780}
781
782#endif
783
784/* Platform driver */
785
786static const struct of_device_id virtio_mmio_match[] = {
787	{ .compatible = "virtio,mmio", },
788	{},
789};
790MODULE_DEVICE_TABLE(of, virtio_mmio_match);
791
792#ifdef CONFIG_ACPI
793static const struct acpi_device_id virtio_mmio_acpi_match[] = {
794	{ "LNRO0005", },
795	{ }
796};
797MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
798#endif
799
800static struct platform_driver virtio_mmio_driver = {
801	.probe		= virtio_mmio_probe,
802	.remove		= virtio_mmio_remove,
803	.driver		= {
804		.name	= "virtio-mmio",
805		.of_match_table	= virtio_mmio_match,
806		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
807#ifdef CONFIG_PM_SLEEP
808		.pm	= &virtio_mmio_pm_ops,
809#endif
810	},
811};
812
813static int __init virtio_mmio_init(void)
814{
815	return platform_driver_register(&virtio_mmio_driver);
816}
817
818static void __exit virtio_mmio_exit(void)
819{
820	platform_driver_unregister(&virtio_mmio_driver);
821	vm_unregister_cmdline_devices();
822}
823
824module_init(virtio_mmio_init);
825module_exit(virtio_mmio_exit);
826
827MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
828MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
829MODULE_LICENSE("GPL");