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i2c: acorn: is tristate and should use module.h
[linux-2.6/btrfs-unstable.git] / drivers / virtio / virtio_mmio.c
blobc600ccfd6922b8226727c516ba8a980502e05458
1 /*
2 * Virtio memory mapped device driver
3 *
4 * Copyright 2011, 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 * Registers layout (all 32-bit wide):
54 *
55 * offset d. name description
56 * ------ -- ---------------- -----------------
57 *
58 * 0x000 R MagicValue Magic value "virt"
59 * 0x004 R Version Device version (current max. 1)
60 * 0x008 R DeviceID Virtio device ID
61 * 0x00c R VendorID Virtio vendor ID
62 *
63 * 0x010 R HostFeatures Features supported by the host
64 * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures
65 *
66 * 0x020 W GuestFeatures Features activated by the guest
67 * 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures
68 * 0x028 W GuestPageSize Size of guest's memory page in bytes
69 *
70 * 0x030 W QueueSel Queue selector
71 * 0x034 R QueueNumMax Maximum size of the currently selected queue
72 * 0x038 W QueueNum Queue size for the currently selected queue
73 * 0x03c W QueueAlign Used Ring alignment for the current queue
74 * 0x040 RW QueuePFN PFN for the currently selected queue
75 *
76 * 0x050 W QueueNotify Queue notifier
77 * 0x060 R InterruptStatus Interrupt status register
78 * 0x064 W InterruptACK Interrupt acknowledge register
79 * 0x070 RW Status Device status register
80 *
81 * 0x100+ RW Device-specific configuration space
82 *
83 * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007
84 *
85 * This work is licensed under the terms of the GNU GPL, version 2 or later.
86 * See the COPYING file in the top-level directory.
87 */
88
89 #define pr_fmt(fmt) "virtio-mmio: " fmt
90
91 #include <linux/highmem.h>
92 #include <linux/interrupt.h>
93 #include <linux/io.h>
94 #include <linux/list.h>
95 #include <linux/module.h>
96 #include <linux/platform_device.h>
97 #include <linux/slab.h>
98 #include <linux/spinlock.h>
99 #include <linux/virtio.h>
100 #include <linux/virtio_config.h>
101 #include <linux/virtio_mmio.h>
102 #include <linux/virtio_ring.h>
103
104
105
106 /* The alignment to use between consumer and producer parts of vring.
107 * Currently hardcoded to the page size. */
108 #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE
109
110
111
112 #define to_virtio_mmio_device(_plat_dev) \
113 container_of(_plat_dev, struct virtio_mmio_device, vdev)
114
115 struct virtio_mmio_device {
116 struct virtio_device vdev;
117 struct platform_device *pdev;
118
119 void __iomem *base;
120 unsigned long version;
121
122 /* a list of queues so we can dispatch IRQs */
123 spinlock_t lock;
124 struct list_head virtqueues;
125 };
126
127 struct virtio_mmio_vq_info {
128 /* the actual virtqueue */
129 struct virtqueue *vq;
130
131 /* the number of entries in the queue */
132 unsigned int num;
133
134 /* the virtual address of the ring queue */
135 void *queue;
136
137 /* the list node for the virtqueues list */
138 struct list_head node;
139 };
140
141
142
143 /* Configuration interface */
144
145 static u32 vm_get_features(struct virtio_device *vdev)
146 {
147 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
148
149 /* TODO: Features > 32 bits */
150 writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
151
152 return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
153 }
154
155 static void vm_finalize_features(struct virtio_device *vdev)
156 {
157 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
158 int i;
159
160 /* Give virtio_ring a chance to accept features. */
161 vring_transport_features(vdev);
162
163 for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
164 writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
165 writel(vdev->features[i],
166 vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
167 }
168 }
169
170 static void vm_get(struct virtio_device *vdev, unsigned offset,
171 void *buf, unsigned len)
172 {
173 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
174 u8 *ptr = buf;
175 int i;
176
177 for (i = 0; i < len; i++)
178 ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
179 }
180
181 static void vm_set(struct virtio_device *vdev, unsigned offset,
182 const void *buf, unsigned len)
183 {
184 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
185 const u8 *ptr = buf;
186 int i;
187
188 for (i = 0; i < len; i++)
189 writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i);
190 }
191
192 static u8 vm_get_status(struct virtio_device *vdev)
193 {
194 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
195
196 return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff;
197 }
198
199 static void vm_set_status(struct virtio_device *vdev, u8 status)
200 {
201 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
202
203 /* We should never be setting status to 0. */
204 BUG_ON(status == 0);
205
206 writel(status, vm_dev->base + VIRTIO_MMIO_STATUS);
207 }
208
209 static void vm_reset(struct virtio_device *vdev)
210 {
211 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
212
213 /* 0 status means a reset. */
214 writel(0, vm_dev->base + VIRTIO_MMIO_STATUS);
215 }
216
217
218
219 /* Transport interface */
220
221 /* the notify function used when creating a virt queue */
222 static bool vm_notify(struct virtqueue *vq)
223 {
224 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
225
226 /* We write the queue's selector into the notification register to
227 * signal the other end */
228 writel(vq->index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
229 return true;
230 }
231
232 /* Notify all virtqueues on an interrupt. */
233 static irqreturn_t vm_interrupt(int irq, void *opaque)
234 {
235 struct virtio_mmio_device *vm_dev = opaque;
236 struct virtio_mmio_vq_info *info;
237 struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
238 struct virtio_driver, driver);
239 unsigned long status;
240 unsigned long flags;
241 irqreturn_t ret = IRQ_NONE;
242
243 /* Read and acknowledge interrupts */
244 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
245 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
246
247 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
248 && vdrv && vdrv->config_changed) {
249 vdrv->config_changed(&vm_dev->vdev);
250 ret = IRQ_HANDLED;
251 }
252
253 if (likely(status & VIRTIO_MMIO_INT_VRING)) {
254 spin_lock_irqsave(&vm_dev->lock, flags);
255 list_for_each_entry(info, &vm_dev->virtqueues, node)
256 ret |= vring_interrupt(irq, info->vq);
257 spin_unlock_irqrestore(&vm_dev->lock, flags);
258 }
259
260 return ret;
261 }
262
263
264
265 static void vm_del_vq(struct virtqueue *vq)
266 {
267 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
268 struct virtio_mmio_vq_info *info = vq->priv;
269 unsigned long flags, size;
270 unsigned int index = vq->index;
271
272 spin_lock_irqsave(&vm_dev->lock, flags);
273 list_del(&info->node);
274 spin_unlock_irqrestore(&vm_dev->lock, flags);
275
276 vring_del_virtqueue(vq);
277
278 /* Select and deactivate the queue */
279 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
280 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
281
282 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
283 free_pages_exact(info->queue, size);
284 kfree(info);
285 }
286
287 static void vm_del_vqs(struct virtio_device *vdev)
288 {
289 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
290 struct virtqueue *vq, *n;
291
292 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
293 vm_del_vq(vq);
294
295 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
296 }
297
298
299
300 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
301 void (*callback)(struct virtqueue *vq),
302 const char *name)
303 {
304 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
305 struct virtio_mmio_vq_info *info;
306 struct virtqueue *vq;
307 unsigned long flags, size;
308 int err;
309
310 if (!name)
311 return NULL;
312
313 /* Select the queue we're interested in */
314 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
315
316 /* Queue shouldn't already be set up. */
317 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
318 err = -ENOENT;
319 goto error_available;
320 }
321
322 /* Allocate and fill out our active queue description */
323 info = kmalloc(sizeof(*info), GFP_KERNEL);
324 if (!info) {
325 err = -ENOMEM;
326 goto error_kmalloc;
327 }
328
329 /* Allocate pages for the queue - start with a queue as big as
330 * possible (limited by maximum size allowed by device), drop down
331 * to a minimal size, just big enough to fit descriptor table
332 * and two rings (which makes it "alignment_size * 2")
333 */
334 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
335
336 /* If the device reports a 0 entry queue, we won't be able to
337 * use it to perform I/O, and vring_new_virtqueue() can't create
338 * empty queues anyway, so don't bother to set up the device.
339 */
340 if (info->num == 0) {
341 err = -ENOENT;
342 goto error_alloc_pages;
343 }
344
345 while (1) {
346 size = PAGE_ALIGN(vring_size(info->num,
347 VIRTIO_MMIO_VRING_ALIGN));
348 /* Did the last iter shrink the queue below minimum size? */
349 if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
350 err = -ENOMEM;
351 goto error_alloc_pages;
352 }
353
354 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
355 if (info->queue)
356 break;
357
358 info->num /= 2;
359 }
360
361 /* Activate the queue */
362 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
363 writel(VIRTIO_MMIO_VRING_ALIGN,
364 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
365 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
366 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
367
368 /* Create the vring */
369 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
370 true, info->queue, vm_notify, callback, name);
371 if (!vq) {
372 err = -ENOMEM;
373 goto error_new_virtqueue;
374 }
375
376 vq->priv = info;
377 info->vq = vq;
378
379 spin_lock_irqsave(&vm_dev->lock, flags);
380 list_add(&info->node, &vm_dev->virtqueues);
381 spin_unlock_irqrestore(&vm_dev->lock, flags);
382
383 return vq;
384
385 error_new_virtqueue:
386 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
387 free_pages_exact(info->queue, size);
388 error_alloc_pages:
389 kfree(info);
390 error_kmalloc:
391 error_available:
392 return ERR_PTR(err);
393 }
394
395 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
396 struct virtqueue *vqs[],
397 vq_callback_t *callbacks[],
398 const char *names[])
399 {
400 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
401 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
402 int i, err;
403
404 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
405 dev_name(&vdev->dev), vm_dev);
406 if (err)
407 return err;
408
409 for (i = 0; i < nvqs; ++i) {
410 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
411 if (IS_ERR(vqs[i])) {
412 vm_del_vqs(vdev);
413 return PTR_ERR(vqs[i]);
414 }
415 }
416
417 return 0;
418 }
419
420 static const char *vm_bus_name(struct virtio_device *vdev)
421 {
422 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
423
424 return vm_dev->pdev->name;
425 }
426
427 static const struct virtio_config_ops virtio_mmio_config_ops = {
428 .get = vm_get,
429 .set = vm_set,
430 .get_status = vm_get_status,
431 .set_status = vm_set_status,
432 .reset = vm_reset,
433 .find_vqs = vm_find_vqs,
434 .del_vqs = vm_del_vqs,
435 .get_features = vm_get_features,
436 .finalize_features = vm_finalize_features,
437 .bus_name = vm_bus_name,
438 };
439
440
441
442 /* Platform device */
443
444 static int virtio_mmio_probe(struct platform_device *pdev)
445 {
446 struct virtio_mmio_device *vm_dev;
447 struct resource *mem;
448 unsigned long magic;
449
450 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
451 if (!mem)
452 return -EINVAL;
453
454 if (!devm_request_mem_region(&pdev->dev, mem->start,
455 resource_size(mem), pdev->name))
456 return -EBUSY;
457
458 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
459 if (!vm_dev)
460 return -ENOMEM;
461
462 vm_dev->vdev.dev.parent = &pdev->dev;
463 vm_dev->vdev.config = &virtio_mmio_config_ops;
464 vm_dev->pdev = pdev;
465 INIT_LIST_HEAD(&vm_dev->virtqueues);
466 spin_lock_init(&vm_dev->lock);
467
468 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
469 if (vm_dev->base == NULL)
470 return -EFAULT;
471
472 /* Check magic value */
473 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
474 if (magic != ('v' | 'i' << 8 | 'r' << 16 | 't' << 24)) {
475 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
476 return -ENODEV;
477 }
478
479 /* Check device version */
480 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
481 if (vm_dev->version != 1) {
482 dev_err(&pdev->dev, "Version %ld not supported!\n",
483 vm_dev->version);
484 return -ENXIO;
485 }
486
487 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
488 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
489
490 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
491
492 platform_set_drvdata(pdev, vm_dev);
493
494 return register_virtio_device(&vm_dev->vdev);
495 }
496
497 static int virtio_mmio_remove(struct platform_device *pdev)
498 {
499 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
500
501 unregister_virtio_device(&vm_dev->vdev);
502
503 return 0;
504 }
505
506
507
508 /* Devices list parameter */
509
510 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
511
512 static struct device vm_cmdline_parent = {
513 .init_name = "virtio-mmio-cmdline",
514 };
515
516 static int vm_cmdline_parent_registered;
517 static int vm_cmdline_id;
518
519 static int vm_cmdline_set(const char *device,
520 const struct kernel_param *kp)
521 {
522 int err;
523 struct resource resources[2] = {};
524 char *str;
525 long long int base, size;
526 unsigned int irq;
527 int processed, consumed = 0;
528 struct platform_device *pdev;
529
530 /* Consume "size" part of the command line parameter */
531 size = memparse(device, &str);
532
533 /* Get "@<base>:<irq>[:<id>]" chunks */
534 processed = sscanf(str, "@%lli:%u%n:%d%n",
535 &base, &irq, &consumed,
536 &vm_cmdline_id, &consumed);
537
538 /*
539 * sscanf() must processes at least 2 chunks; also there
540 * must be no extra characters after the last chunk, so
541 * str[consumed] must be '\0'
542 */
543 if (processed < 2 || str[consumed])
544 return -EINVAL;
545
546 resources[0].flags = IORESOURCE_MEM;
547 resources[0].start = base;
548 resources[0].end = base + size - 1;
549
550 resources[1].flags = IORESOURCE_IRQ;
551 resources[1].start = resources[1].end = irq;
552
553 if (!vm_cmdline_parent_registered) {
554 err = device_register(&vm_cmdline_parent);
555 if (err) {
556 pr_err("Failed to register parent device!\n");
557 return err;
558 }
559 vm_cmdline_parent_registered = 1;
560 }
561
562 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
563 vm_cmdline_id,
564 (unsigned long long)resources[0].start,
565 (unsigned long long)resources[0].end,
566 (int)resources[1].start);
567
568 pdev = platform_device_register_resndata(&vm_cmdline_parent,
569 "virtio-mmio", vm_cmdline_id++,
570 resources, ARRAY_SIZE(resources), NULL, 0);
571 if (IS_ERR(pdev))
572 return PTR_ERR(pdev);
573
574 return 0;
575 }
576
577 static int vm_cmdline_get_device(struct device *dev, void *data)
578 {
579 char *buffer = data;
580 unsigned int len = strlen(buffer);
581 struct platform_device *pdev = to_platform_device(dev);
582
583 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
584 pdev->resource[0].end - pdev->resource[0].start + 1ULL,
585 (unsigned long long)pdev->resource[0].start,
586 (unsigned long long)pdev->resource[1].start,
587 pdev->id);
588 return 0;
589 }
590
591 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
592 {
593 buffer[0] = '\0';
594 device_for_each_child(&vm_cmdline_parent, buffer,
595 vm_cmdline_get_device);
596 return strlen(buffer) + 1;
597 }
598
599 static struct kernel_param_ops vm_cmdline_param_ops = {
600 .set = vm_cmdline_set,
601 .get = vm_cmdline_get,
602 };
603
604 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
605
606 static int vm_unregister_cmdline_device(struct device *dev,
607 void *data)
608 {
609 platform_device_unregister(to_platform_device(dev));
610
611 return 0;
612 }
613
614 static void vm_unregister_cmdline_devices(void)
615 {
616 if (vm_cmdline_parent_registered) {
617 device_for_each_child(&vm_cmdline_parent, NULL,
618 vm_unregister_cmdline_device);
619 device_unregister(&vm_cmdline_parent);
620 vm_cmdline_parent_registered = 0;
621 }
622 }
623
624 #else
625
626 static void vm_unregister_cmdline_devices(void)
627 {
628 }
629
630 #endif
631
632 /* Platform driver */
633
634 static struct of_device_id virtio_mmio_match[] = {
635 { .compatible = "virtio,mmio", },
636 {},
637 };
638 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
639
640 static struct platform_driver virtio_mmio_driver = {
641 .probe = virtio_mmio_probe,
642 .remove = virtio_mmio_remove,
643 .driver = {
644 .name = "virtio-mmio",
645 .owner = THIS_MODULE,
646 .of_match_table = virtio_mmio_match,
647 },
648 };
649
650 static int __init virtio_mmio_init(void)
651 {
652 return platform_driver_register(&virtio_mmio_driver);
653 }
654
655 static void __exit virtio_mmio_exit(void)
656 {
657 platform_driver_unregister(&virtio_mmio_driver);
658 vm_unregister_cmdline_devices();
659 }
660
661 module_init(virtio_mmio_init);
662 module_exit(virtio_mmio_exit);
663
664 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
665 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
666 MODULE_LICENSE("GPL");
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