xref: /openbmc/linux/drivers/virtio/virtio_mmio.c (revision fab7f259)
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/spinlock.h>
69 #include <linux/virtio.h>
70 #include <linux/virtio_config.h>
71 #include <uapi/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 list node for the virtqueues list */
102 	struct list_head node;
103 };
104 
105 
106 
107 /* Configuration interface */
108 
vm_get_features(struct virtio_device * vdev)109 static u64 vm_get_features(struct virtio_device *vdev)
110 {
111 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
112 	u64 features;
113 
114 	writel(1, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
115 	features = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
116 	features <<= 32;
117 
118 	writel(0, vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES_SEL);
119 	features |= readl(vm_dev->base + VIRTIO_MMIO_DEVICE_FEATURES);
120 
121 	return features;
122 }
123 
vm_finalize_features(struct virtio_device * vdev)124 static int vm_finalize_features(struct virtio_device *vdev)
125 {
126 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
127 
128 	/* Give virtio_ring a chance to accept features. */
129 	vring_transport_features(vdev);
130 
131 	/* Make sure there are no mixed devices */
132 	if (vm_dev->version == 2 &&
133 			!__virtio_test_bit(vdev, VIRTIO_F_VERSION_1)) {
134 		dev_err(&vdev->dev, "New virtio-mmio devices (version 2) must provide VIRTIO_F_VERSION_1 feature!\n");
135 		return -EINVAL;
136 	}
137 
138 	writel(1, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
139 	writel((u32)(vdev->features >> 32),
140 			vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
141 
142 	writel(0, vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES_SEL);
143 	writel((u32)vdev->features,
144 			vm_dev->base + VIRTIO_MMIO_DRIVER_FEATURES);
145 
146 	return 0;
147 }
148 
vm_get(struct virtio_device * vdev,unsigned int offset,void * buf,unsigned int len)149 static void vm_get(struct virtio_device *vdev, unsigned int offset,
150 		   void *buf, unsigned int len)
151 {
152 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
153 	void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
154 	u8 b;
155 	__le16 w;
156 	__le32 l;
157 
158 	if (vm_dev->version == 1) {
159 		u8 *ptr = buf;
160 		int i;
161 
162 		for (i = 0; i < len; i++)
163 			ptr[i] = readb(base + offset + i);
164 		return;
165 	}
166 
167 	switch (len) {
168 	case 1:
169 		b = readb(base + offset);
170 		memcpy(buf, &b, sizeof b);
171 		break;
172 	case 2:
173 		w = cpu_to_le16(readw(base + offset));
174 		memcpy(buf, &w, sizeof w);
175 		break;
176 	case 4:
177 		l = cpu_to_le32(readl(base + offset));
178 		memcpy(buf, &l, sizeof l);
179 		break;
180 	case 8:
181 		l = cpu_to_le32(readl(base + offset));
182 		memcpy(buf, &l, sizeof l);
183 		l = cpu_to_le32(ioread32(base + offset + sizeof l));
184 		memcpy(buf + sizeof l, &l, sizeof l);
185 		break;
186 	default:
187 		BUG();
188 	}
189 }
190 
vm_set(struct virtio_device * vdev,unsigned int offset,const void * buf,unsigned int len)191 static void vm_set(struct virtio_device *vdev, unsigned int offset,
192 		   const void *buf, unsigned int len)
193 {
194 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
195 	void __iomem *base = vm_dev->base + VIRTIO_MMIO_CONFIG;
196 	u8 b;
197 	__le16 w;
198 	__le32 l;
199 
200 	if (vm_dev->version == 1) {
201 		const u8 *ptr = buf;
202 		int i;
203 
204 		for (i = 0; i < len; i++)
205 			writeb(ptr[i], base + offset + i);
206 
207 		return;
208 	}
209 
210 	switch (len) {
211 	case 1:
212 		memcpy(&b, buf, sizeof b);
213 		writeb(b, base + offset);
214 		break;
215 	case 2:
216 		memcpy(&w, buf, sizeof w);
217 		writew(le16_to_cpu(w), base + offset);
218 		break;
219 	case 4:
220 		memcpy(&l, buf, sizeof l);
221 		writel(le32_to_cpu(l), base + offset);
222 		break;
223 	case 8:
224 		memcpy(&l, buf, sizeof l);
225 		writel(le32_to_cpu(l), base + offset);
226 		memcpy(&l, buf + sizeof l, sizeof l);
227 		writel(le32_to_cpu(l), base + offset + sizeof l);
228 		break;
229 	default:
230 		BUG();
231 	}
232 }
233 
vm_generation(struct virtio_device * vdev)234 static u32 vm_generation(struct virtio_device *vdev)
235 {
236 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
237 
238 	if (vm_dev->version == 1)
239 		return 0;
240 	else
241 		return readl(vm_dev->base + VIRTIO_MMIO_CONFIG_GENERATION);
242 }
243 
vm_get_status(struct virtio_device * vdev)244 static u8 vm_get_status(struct virtio_device *vdev)
245 {
246 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
247 
248 	return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
249 }
250 
vm_set_status(struct virtio_device * vdev,u8 status)251 static void vm_set_status(struct virtio_device *vdev, u8 status)
252 {
253 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
254 
255 	/* We should never be setting status to 0. */
256 	BUG_ON(status == 0);
257 
258 	/*
259 	 * Per memory-barriers.txt, wmb() is not needed to guarantee
260 	 * that the cache coherent memory writes have completed
261 	 * before writing to the MMIO region.
262 	 */
263 	writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
264 }
265 
vm_reset(struct virtio_device * vdev)266 static void vm_reset(struct virtio_device *vdev)
267 {
268 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
269 
270 	/* 0 status means a reset. */
271 	writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
272 }
273 
274 
275 
276 /* Transport interface */
277 
278 /* the notify function used when creating a virt queue */
vm_notify(struct virtqueue * vq)279 static bool vm_notify(struct virtqueue *vq)
280 {
281 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
282 
283 	/* We write the queue's selector into the notification register to
284 	 * signal the other end */
285 	writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
286 	return true;
287 }
288 
vm_notify_with_data(struct virtqueue * vq)289 static bool vm_notify_with_data(struct virtqueue *vq)
290 {
291 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
292 	u32 data = vring_notification_data(vq);
293 
294 	writel(data, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
295 
296 	return true;
297 }
298 
299 /* Notify all virtqueues on an interrupt. */
vm_interrupt(int irq,void * opaque)300 static irqreturn_t vm_interrupt(int irq, void *opaque)
301 {
302 	struct virtio_mmio_device *vm_dev = opaque;
303 	struct virtio_mmio_vq_info *info;
304 	unsigned long status;
305 	unsigned long flags;
306 	irqreturn_t ret = IRQ_NONE;
307 
308 	/* Read and acknowledge interrupts */
309 	status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
310 	writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
311 
312 	if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)) {
313 		virtio_config_changed(&vm_dev->vdev);
314 		ret = IRQ_HANDLED;
315 	}
316 
317 	if (likely(status & VIRTIO_MMIO_INT_VRING)) {
318 		spin_lock_irqsave(&vm_dev->lock, flags);
319 		list_for_each_entry(info, &vm_dev->virtqueues, node)
320 			ret |= vring_interrupt(irq, info->vq);
321 		spin_unlock_irqrestore(&vm_dev->lock, flags);
322 	}
323 
324 	return ret;
325 }
326 
327 
328 
vm_del_vq(struct virtqueue * vq)329 static void vm_del_vq(struct virtqueue *vq)
330 {
331 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
332 	struct virtio_mmio_vq_info *info = vq->priv;
333 	unsigned long flags;
334 	unsigned int index = vq->index;
335 
336 	spin_lock_irqsave(&vm_dev->lock, flags);
337 	list_del(&info->node);
338 	spin_unlock_irqrestore(&vm_dev->lock, flags);
339 
340 	/* Select and deactivate the queue */
341 	writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
342 	if (vm_dev->version == 1) {
343 		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
344 	} else {
345 		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
346 		WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
347 	}
348 
349 	vring_del_virtqueue(vq);
350 
351 	kfree(info);
352 }
353 
vm_del_vqs(struct virtio_device * vdev)354 static void vm_del_vqs(struct virtio_device *vdev)
355 {
356 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
357 	struct virtqueue *vq, *n;
358 
359 	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
360 		vm_del_vq(vq);
361 
362 	free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
363 }
364 
vm_synchronize_cbs(struct virtio_device * vdev)365 static void vm_synchronize_cbs(struct virtio_device *vdev)
366 {
367 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
368 
369 	synchronize_irq(platform_get_irq(vm_dev->pdev, 0));
370 }
371 
vm_setup_vq(struct virtio_device * vdev,unsigned int index,void (* callback)(struct virtqueue * vq),const char * name,bool ctx)372 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned int index,
373 				  void (*callback)(struct virtqueue *vq),
374 				  const char *name, bool ctx)
375 {
376 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
377 	bool (*notify)(struct virtqueue *vq);
378 	struct virtio_mmio_vq_info *info;
379 	struct virtqueue *vq;
380 	unsigned long flags;
381 	unsigned int num;
382 	int err;
383 
384 	if (__virtio_test_bit(vdev, VIRTIO_F_NOTIFICATION_DATA))
385 		notify = vm_notify_with_data;
386 	else
387 		notify = vm_notify;
388 
389 	if (!name)
390 		return NULL;
391 
392 	/* Select the queue we're interested in */
393 	writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
394 
395 	/* Queue shouldn't already be set up. */
396 	if (readl(vm_dev->base + (vm_dev->version == 1 ?
397 			VIRTIO_MMIO_QUEUE_PFN : VIRTIO_MMIO_QUEUE_READY))) {
398 		err = -ENOENT;
399 		goto error_available;
400 	}
401 
402 	/* Allocate and fill out our active queue description */
403 	info = kmalloc(sizeof(*info), GFP_KERNEL);
404 	if (!info) {
405 		err = -ENOMEM;
406 		goto error_kmalloc;
407 	}
408 
409 	num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
410 	if (num == 0) {
411 		err = -ENOENT;
412 		goto error_new_virtqueue;
413 	}
414 
415 	/* Create the vring */
416 	vq = vring_create_virtqueue(index, num, VIRTIO_MMIO_VRING_ALIGN, vdev,
417 				 true, true, ctx, notify, callback, name);
418 	if (!vq) {
419 		err = -ENOMEM;
420 		goto error_new_virtqueue;
421 	}
422 
423 	vq->num_max = num;
424 
425 	/* Activate the queue */
426 	writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
427 	if (vm_dev->version == 1) {
428 		u64 q_pfn = virtqueue_get_desc_addr(vq) >> PAGE_SHIFT;
429 
430 		/*
431 		 * virtio-mmio v1 uses a 32bit QUEUE PFN. If we have something
432 		 * that doesn't fit in 32bit, fail the setup rather than
433 		 * pretending to be successful.
434 		 */
435 		if (q_pfn >> 32) {
436 			dev_err(&vdev->dev,
437 				"platform bug: legacy virtio-mmio must not be used with RAM above 0x%llxGB\n",
438 				0x1ULL << (32 + PAGE_SHIFT - 30));
439 			err = -E2BIG;
440 			goto error_bad_pfn;
441 		}
442 
443 		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
444 		writel(q_pfn, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
445 	} else {
446 		u64 addr;
447 
448 		addr = virtqueue_get_desc_addr(vq);
449 		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_LOW);
450 		writel((u32)(addr >> 32),
451 				vm_dev->base + VIRTIO_MMIO_QUEUE_DESC_HIGH);
452 
453 		addr = virtqueue_get_avail_addr(vq);
454 		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_LOW);
455 		writel((u32)(addr >> 32),
456 				vm_dev->base + VIRTIO_MMIO_QUEUE_AVAIL_HIGH);
457 
458 		addr = virtqueue_get_used_addr(vq);
459 		writel((u32)addr, vm_dev->base + VIRTIO_MMIO_QUEUE_USED_LOW);
460 		writel((u32)(addr >> 32),
461 				vm_dev->base + VIRTIO_MMIO_QUEUE_USED_HIGH);
462 
463 		writel(1, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
464 	}
465 
466 	vq->priv = info;
467 	info->vq = vq;
468 
469 	spin_lock_irqsave(&vm_dev->lock, flags);
470 	list_add(&info->node, &vm_dev->virtqueues);
471 	spin_unlock_irqrestore(&vm_dev->lock, flags);
472 
473 	return vq;
474 
475 error_bad_pfn:
476 	vring_del_virtqueue(vq);
477 error_new_virtqueue:
478 	if (vm_dev->version == 1) {
479 		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
480 	} else {
481 		writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_READY);
482 		WARN_ON(readl(vm_dev->base + VIRTIO_MMIO_QUEUE_READY));
483 	}
484 	kfree(info);
485 error_kmalloc:
486 error_available:
487 	return ERR_PTR(err);
488 }
489 
vm_find_vqs(struct virtio_device * vdev,unsigned int nvqs,struct virtqueue * vqs[],vq_callback_t * callbacks[],const char * const names[],const bool * ctx,struct irq_affinity * desc)490 static int vm_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
491 		       struct virtqueue *vqs[],
492 		       vq_callback_t *callbacks[],
493 		       const char * const names[],
494 		       const bool *ctx,
495 		       struct irq_affinity *desc)
496 {
497 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
498 	int irq = platform_get_irq(vm_dev->pdev, 0);
499 	int i, err, queue_idx = 0;
500 
501 	if (irq < 0)
502 		return irq;
503 
504 	err = request_irq(irq, vm_interrupt, IRQF_SHARED,
505 			dev_name(&vdev->dev), vm_dev);
506 	if (err)
507 		return err;
508 
509 	if (of_property_read_bool(vm_dev->pdev->dev.of_node, "wakeup-source"))
510 		enable_irq_wake(irq);
511 
512 	for (i = 0; i < nvqs; ++i) {
513 		if (!names[i]) {
514 			vqs[i] = NULL;
515 			continue;
516 		}
517 
518 		vqs[i] = vm_setup_vq(vdev, queue_idx++, callbacks[i], names[i],
519 				     ctx ? ctx[i] : false);
520 		if (IS_ERR(vqs[i])) {
521 			vm_del_vqs(vdev);
522 			return PTR_ERR(vqs[i]);
523 		}
524 	}
525 
526 	return 0;
527 }
528 
vm_bus_name(struct virtio_device * vdev)529 static const char *vm_bus_name(struct virtio_device *vdev)
530 {
531 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
532 
533 	return vm_dev->pdev->name;
534 }
535 
vm_get_shm_region(struct virtio_device * vdev,struct virtio_shm_region * region,u8 id)536 static bool vm_get_shm_region(struct virtio_device *vdev,
537 			      struct virtio_shm_region *region, u8 id)
538 {
539 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
540 	u64 len, addr;
541 
542 	/* Select the region we're interested in */
543 	writel(id, vm_dev->base + VIRTIO_MMIO_SHM_SEL);
544 
545 	/* Read the region size */
546 	len = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_LOW);
547 	len |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_LEN_HIGH) << 32;
548 
549 	region->len = len;
550 
551 	/* Check if region length is -1. If that's the case, the shared memory
552 	 * region does not exist and there is no need to proceed further.
553 	 */
554 	if (len == ~(u64)0)
555 		return false;
556 
557 	/* Read the region base address */
558 	addr = (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_LOW);
559 	addr |= (u64) readl(vm_dev->base + VIRTIO_MMIO_SHM_BASE_HIGH) << 32;
560 
561 	region->addr = addr;
562 
563 	return true;
564 }
565 
566 static const struct virtio_config_ops virtio_mmio_config_ops = {
567 	.get		= vm_get,
568 	.set		= vm_set,
569 	.generation	= vm_generation,
570 	.get_status	= vm_get_status,
571 	.set_status	= vm_set_status,
572 	.reset		= vm_reset,
573 	.find_vqs	= vm_find_vqs,
574 	.del_vqs	= vm_del_vqs,
575 	.get_features	= vm_get_features,
576 	.finalize_features = vm_finalize_features,
577 	.bus_name	= vm_bus_name,
578 	.get_shm_region = vm_get_shm_region,
579 	.synchronize_cbs = vm_synchronize_cbs,
580 };
581 
582 #ifdef CONFIG_PM_SLEEP
virtio_mmio_freeze(struct device * dev)583 static int virtio_mmio_freeze(struct device *dev)
584 {
585 	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
586 
587 	return virtio_device_freeze(&vm_dev->vdev);
588 }
589 
virtio_mmio_restore(struct device * dev)590 static int virtio_mmio_restore(struct device *dev)
591 {
592 	struct virtio_mmio_device *vm_dev = dev_get_drvdata(dev);
593 
594 	if (vm_dev->version == 1)
595 		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
596 
597 	return virtio_device_restore(&vm_dev->vdev);
598 }
599 
600 static const struct dev_pm_ops virtio_mmio_pm_ops = {
601 	SET_SYSTEM_SLEEP_PM_OPS(virtio_mmio_freeze, virtio_mmio_restore)
602 };
603 #endif
604 
virtio_mmio_release_dev(struct device * _d)605 static void virtio_mmio_release_dev(struct device *_d)
606 {
607 	struct virtio_device *vdev =
608 			container_of(_d, struct virtio_device, dev);
609 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
610 
611 	kfree(vm_dev);
612 }
613 
614 /* Platform device */
615 
virtio_mmio_probe(struct platform_device * pdev)616 static int virtio_mmio_probe(struct platform_device *pdev)
617 {
618 	struct virtio_mmio_device *vm_dev;
619 	unsigned long magic;
620 	int rc;
621 
622 	vm_dev = kzalloc(sizeof(*vm_dev), GFP_KERNEL);
623 	if (!vm_dev)
624 		return -ENOMEM;
625 
626 	vm_dev->vdev.dev.parent = &pdev->dev;
627 	vm_dev->vdev.dev.release = virtio_mmio_release_dev;
628 	vm_dev->vdev.config = &virtio_mmio_config_ops;
629 	vm_dev->pdev = pdev;
630 	INIT_LIST_HEAD(&vm_dev->virtqueues);
631 	spin_lock_init(&vm_dev->lock);
632 
633 	vm_dev->base = devm_platform_ioremap_resource(pdev, 0);
634 	if (IS_ERR(vm_dev->base)) {
635 		rc = PTR_ERR(vm_dev->base);
636 		goto free_vm_dev;
637 	}
638 
639 	/* Check magic value */
640 	magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
641 	if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
642 		dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
643 		rc = -ENODEV;
644 		goto free_vm_dev;
645 	}
646 
647 	/* Check device version */
648 	vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
649 	if (vm_dev->version < 1 || vm_dev->version > 2) {
650 		dev_err(&pdev->dev, "Version %ld not supported!\n",
651 				vm_dev->version);
652 		rc = -ENXIO;
653 		goto free_vm_dev;
654 	}
655 
656 	vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
657 	if (vm_dev->vdev.id.device == 0) {
658 		/*
659 		 * virtio-mmio device with an ID 0 is a (dummy) placeholder
660 		 * with no function. End probing now with no error reported.
661 		 */
662 		rc = -ENODEV;
663 		goto free_vm_dev;
664 	}
665 	vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
666 
667 	if (vm_dev->version == 1) {
668 		writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
669 
670 		rc = dma_set_mask(&pdev->dev, DMA_BIT_MASK(64));
671 		/*
672 		 * In the legacy case, ensure our coherently-allocated virtio
673 		 * ring will be at an address expressable as a 32-bit PFN.
674 		 */
675 		if (!rc)
676 			dma_set_coherent_mask(&pdev->dev,
677 					      DMA_BIT_MASK(32 + PAGE_SHIFT));
678 	} else {
679 		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
680 	}
681 	if (rc)
682 		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
683 	if (rc)
684 		dev_warn(&pdev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
685 
686 	platform_set_drvdata(pdev, vm_dev);
687 
688 	rc = register_virtio_device(&vm_dev->vdev);
689 	if (rc)
690 		put_device(&vm_dev->vdev.dev);
691 
692 	return rc;
693 
694 free_vm_dev:
695 	kfree(vm_dev);
696 	return rc;
697 }
698 
virtio_mmio_remove(struct platform_device * pdev)699 static int virtio_mmio_remove(struct platform_device *pdev)
700 {
701 	struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
702 	unregister_virtio_device(&vm_dev->vdev);
703 
704 	return 0;
705 }
706 
707 
708 
709 /* Devices list parameter */
710 
711 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
712 
713 static struct device vm_cmdline_parent = {
714 	.init_name = "virtio-mmio-cmdline",
715 };
716 
717 static int vm_cmdline_parent_registered;
718 static int vm_cmdline_id;
719 
vm_cmdline_set(const char * device,const struct kernel_param * kp)720 static int vm_cmdline_set(const char *device,
721 		const struct kernel_param *kp)
722 {
723 	int err;
724 	struct resource resources[2] = {};
725 	char *str;
726 	long long base, size;
727 	unsigned int irq;
728 	int processed, consumed = 0;
729 	struct platform_device *pdev;
730 
731 	/* Consume "size" part of the command line parameter */
732 	size = memparse(device, &str);
733 
734 	/* Get "@<base>:<irq>[:<id>]" chunks */
735 	processed = sscanf(str, "@%lli:%u%n:%d%n",
736 			&base, &irq, &consumed,
737 			&vm_cmdline_id, &consumed);
738 
739 	/*
740 	 * sscanf() must process at least 2 chunks; also there
741 	 * must be no extra characters after the last chunk, so
742 	 * str[consumed] must be '\0'
743 	 */
744 	if (processed < 2 || str[consumed] || irq == 0)
745 		return -EINVAL;
746 
747 	resources[0].flags = IORESOURCE_MEM;
748 	resources[0].start = base;
749 	resources[0].end = base + size - 1;
750 
751 	resources[1].flags = IORESOURCE_IRQ;
752 	resources[1].start = resources[1].end = irq;
753 
754 	if (!vm_cmdline_parent_registered) {
755 		err = device_register(&vm_cmdline_parent);
756 		if (err) {
757 			put_device(&vm_cmdline_parent);
758 			pr_err("Failed to register parent device!\n");
759 			return err;
760 		}
761 		vm_cmdline_parent_registered = 1;
762 	}
763 
764 	pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
765 		       vm_cmdline_id,
766 		       (unsigned long long)resources[0].start,
767 		       (unsigned long long)resources[0].end,
768 		       (int)resources[1].start);
769 
770 	pdev = platform_device_register_resndata(&vm_cmdline_parent,
771 			"virtio-mmio", vm_cmdline_id++,
772 			resources, ARRAY_SIZE(resources), NULL, 0);
773 
774 	return PTR_ERR_OR_ZERO(pdev);
775 }
776 
vm_cmdline_get_device(struct device * dev,void * data)777 static int vm_cmdline_get_device(struct device *dev, void *data)
778 {
779 	char *buffer = data;
780 	unsigned int len = strlen(buffer);
781 	struct platform_device *pdev = to_platform_device(dev);
782 
783 	snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
784 			pdev->resource[0].end - pdev->resource[0].start + 1ULL,
785 			(unsigned long long)pdev->resource[0].start,
786 			(unsigned long long)pdev->resource[1].start,
787 			pdev->id);
788 	return 0;
789 }
790 
vm_cmdline_get(char * buffer,const struct kernel_param * kp)791 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
792 {
793 	buffer[0] = '\0';
794 	device_for_each_child(&vm_cmdline_parent, buffer,
795 			vm_cmdline_get_device);
796 	return strlen(buffer) + 1;
797 }
798 
799 static const struct kernel_param_ops vm_cmdline_param_ops = {
800 	.set = vm_cmdline_set,
801 	.get = vm_cmdline_get,
802 };
803 
804 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
805 
vm_unregister_cmdline_device(struct device * dev,void * data)806 static int vm_unregister_cmdline_device(struct device *dev,
807 		void *data)
808 {
809 	platform_device_unregister(to_platform_device(dev));
810 
811 	return 0;
812 }
813 
vm_unregister_cmdline_devices(void)814 static void vm_unregister_cmdline_devices(void)
815 {
816 	if (vm_cmdline_parent_registered) {
817 		device_for_each_child(&vm_cmdline_parent, NULL,
818 				vm_unregister_cmdline_device);
819 		device_unregister(&vm_cmdline_parent);
820 		vm_cmdline_parent_registered = 0;
821 	}
822 }
823 
824 #else
825 
vm_unregister_cmdline_devices(void)826 static void vm_unregister_cmdline_devices(void)
827 {
828 }
829 
830 #endif
831 
832 /* Platform driver */
833 
834 static const struct of_device_id virtio_mmio_match[] = {
835 	{ .compatible = "virtio,mmio", },
836 	{},
837 };
838 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
839 
840 #ifdef CONFIG_ACPI
841 static const struct acpi_device_id virtio_mmio_acpi_match[] = {
842 	{ "LNRO0005", },
843 	{ }
844 };
845 MODULE_DEVICE_TABLE(acpi, virtio_mmio_acpi_match);
846 #endif
847 
848 static struct platform_driver virtio_mmio_driver = {
849 	.probe		= virtio_mmio_probe,
850 	.remove		= virtio_mmio_remove,
851 	.driver		= {
852 		.name	= "virtio-mmio",
853 		.of_match_table	= virtio_mmio_match,
854 		.acpi_match_table = ACPI_PTR(virtio_mmio_acpi_match),
855 #ifdef CONFIG_PM_SLEEP
856 		.pm	= &virtio_mmio_pm_ops,
857 #endif
858 	},
859 };
860 
virtio_mmio_init(void)861 static int __init virtio_mmio_init(void)
862 {
863 	return platform_driver_register(&virtio_mmio_driver);
864 }
865 
virtio_mmio_exit(void)866 static void __exit virtio_mmio_exit(void)
867 {
868 	platform_driver_unregister(&virtio_mmio_driver);
869 	vm_unregister_cmdline_devices();
870 }
871 
872 module_init(virtio_mmio_init);
873 module_exit(virtio_mmio_exit);
874 
875 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
876 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
877 MODULE_LICENSE("GPL");
878