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[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / virtio / virtio_mmio.c
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 * 0x060 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 void 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(virtqueue_get_queue_index(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY);
229 }
230
231 /* Notify all virtqueues on an interrupt. */
232 static irqreturn_t vm_interrupt(int irq, void *opaque)
233 {
234 struct virtio_mmio_device *vm_dev = opaque;
235 struct virtio_mmio_vq_info *info;
236 struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver,
237 struct virtio_driver, driver);
238 unsigned long status;
239 unsigned long flags;
240 irqreturn_t ret = IRQ_NONE;
241
242 /* Read and acknowledge interrupts */
243 status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS);
244 writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK);
245
246 if (unlikely(status & VIRTIO_MMIO_INT_CONFIG)
247 && vdrv && vdrv->config_changed) {
248 vdrv->config_changed(&vm_dev->vdev);
249 ret = IRQ_HANDLED;
250 }
251
252 if (likely(status & VIRTIO_MMIO_INT_VRING)) {
253 spin_lock_irqsave(&vm_dev->lock, flags);
254 list_for_each_entry(info, &vm_dev->virtqueues, node)
255 ret |= vring_interrupt(irq, info->vq);
256 spin_unlock_irqrestore(&vm_dev->lock, flags);
257 }
258
259 return ret;
260 }
261
262
263
264 static void vm_del_vq(struct virtqueue *vq)
265 {
266 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev);
267 struct virtio_mmio_vq_info *info = vq->priv;
268 unsigned long flags, size;
269 unsigned int index = virtqueue_get_queue_index(vq);
270
271 spin_lock_irqsave(&vm_dev->lock, flags);
272 list_del(&info->node);
273 spin_unlock_irqrestore(&vm_dev->lock, flags);
274
275 vring_del_virtqueue(vq);
276
277 /* Select and deactivate the queue */
278 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
279 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
280
281 size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN));
282 free_pages_exact(info->queue, size);
283 kfree(info);
284 }
285
286 static void vm_del_vqs(struct virtio_device *vdev)
287 {
288 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
289 struct virtqueue *vq, *n;
290
291 list_for_each_entry_safe(vq, n, &vdev->vqs, list)
292 vm_del_vq(vq);
293
294 free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev);
295 }
296
297
298
299 static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
300 void (*callback)(struct virtqueue *vq),
301 const char *name)
302 {
303 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
304 struct virtio_mmio_vq_info *info;
305 struct virtqueue *vq;
306 unsigned long flags, size;
307 int err;
308
309 /* Select the queue we're interested in */
310 writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL);
311
312 /* Queue shouldn't already be set up. */
313 if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) {
314 err = -ENOENT;
315 goto error_available;
316 }
317
318 /* Allocate and fill out our active queue description */
319 info = kmalloc(sizeof(*info), GFP_KERNEL);
320 if (!info) {
321 err = -ENOMEM;
322 goto error_kmalloc;
323 }
324
325 /* Allocate pages for the queue - start with a queue as big as
326 * possible (limited by maximum size allowed by device), drop down
327 * to a minimal size, just big enough to fit descriptor table
328 * and two rings (which makes it "alignment_size * 2")
329 */
330 info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX);
331 while (1) {
332 size = PAGE_ALIGN(vring_size(info->num,
333 VIRTIO_MMIO_VRING_ALIGN));
334 /* Already smallest possible allocation? */
335 if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
336 err = -ENOMEM;
337 goto error_alloc_pages;
338 }
339
340 info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO);
341 if (info->queue)
342 break;
343
344 info->num /= 2;
345 }
346
347 /* Activate the queue */
348 writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
349 writel(VIRTIO_MMIO_VRING_ALIGN,
350 vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN);
351 writel(virt_to_phys(info->queue) >> PAGE_SHIFT,
352 vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
353
354 /* Create the vring */
355 vq = vring_new_virtqueue(index, info->num, VIRTIO_MMIO_VRING_ALIGN, vdev,
356 true, info->queue, vm_notify, callback, name);
357 if (!vq) {
358 err = -ENOMEM;
359 goto error_new_virtqueue;
360 }
361
362 vq->priv = info;
363 info->vq = vq;
364
365 spin_lock_irqsave(&vm_dev->lock, flags);
366 list_add(&info->node, &vm_dev->virtqueues);
367 spin_unlock_irqrestore(&vm_dev->lock, flags);
368
369 return vq;
370
371 error_new_virtqueue:
372 writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN);
373 free_pages_exact(info->queue, size);
374 error_alloc_pages:
375 kfree(info);
376 error_kmalloc:
377 error_available:
378 return ERR_PTR(err);
379 }
380
381 static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
382 struct virtqueue *vqs[],
383 vq_callback_t *callbacks[],
384 const char *names[])
385 {
386 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
387 unsigned int irq = platform_get_irq(vm_dev->pdev, 0);
388 int i, err;
389
390 err = request_irq(irq, vm_interrupt, IRQF_SHARED,
391 dev_name(&vdev->dev), vm_dev);
392 if (err)
393 return err;
394
395 for (i = 0; i < nvqs; ++i) {
396 vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]);
397 if (IS_ERR(vqs[i])) {
398 vm_del_vqs(vdev);
399 return PTR_ERR(vqs[i]);
400 }
401 }
402
403 return 0;
404 }
405
406 static const char *vm_bus_name(struct virtio_device *vdev)
407 {
408 struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
409
410 return vm_dev->pdev->name;
411 }
412
413 static struct virtio_config_ops virtio_mmio_config_ops = {
414 .get = vm_get,
415 .set = vm_set,
416 .get_status = vm_get_status,
417 .set_status = vm_set_status,
418 .reset = vm_reset,
419 .find_vqs = vm_find_vqs,
420 .del_vqs = vm_del_vqs,
421 .get_features = vm_get_features,
422 .finalize_features = vm_finalize_features,
423 .bus_name = vm_bus_name,
424 };
425
426
427
428 /* Platform device */
429
430 static int __devinit virtio_mmio_probe(struct platform_device *pdev)
431 {
432 struct virtio_mmio_device *vm_dev;
433 struct resource *mem;
434 unsigned long magic;
435
436 mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
437 if (!mem)
438 return -EINVAL;
439
440 if (!devm_request_mem_region(&pdev->dev, mem->start,
441 resource_size(mem), pdev->name))
442 return -EBUSY;
443
444 vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL);
445 if (!vm_dev)
446 return -ENOMEM;
447
448 vm_dev->vdev.dev.parent = &pdev->dev;
449 vm_dev->vdev.config = &virtio_mmio_config_ops;
450 vm_dev->pdev = pdev;
451 INIT_LIST_HEAD(&vm_dev->virtqueues);
452 spin_lock_init(&vm_dev->lock);
453
454 vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem));
455 if (vm_dev->base == NULL)
456 return -EFAULT;
457
458 /* Check magic value */
459 magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE);
460 if (memcmp(&magic, "virt", 4) != 0) {
461 dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic);
462 return -ENODEV;
463 }
464
465 /* Check device version */
466 vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION);
467 if (vm_dev->version != 1) {
468 dev_err(&pdev->dev, "Version %ld not supported!\n",
469 vm_dev->version);
470 return -ENXIO;
471 }
472
473 vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID);
474 vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID);
475
476 writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE);
477
478 platform_set_drvdata(pdev, vm_dev);
479
480 return register_virtio_device(&vm_dev->vdev);
481 }
482
483 static int __devexit virtio_mmio_remove(struct platform_device *pdev)
484 {
485 struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev);
486
487 unregister_virtio_device(&vm_dev->vdev);
488
489 return 0;
490 }
491
492
493
494 /* Devices list parameter */
495
496 #if defined(CONFIG_VIRTIO_MMIO_CMDLINE_DEVICES)
497
498 static struct device vm_cmdline_parent = {
499 .init_name = "virtio-mmio-cmdline",
500 };
501
502 static int vm_cmdline_parent_registered;
503 static int vm_cmdline_id;
504
505 static int vm_cmdline_set(const char *device,
506 const struct kernel_param *kp)
507 {
508 int err;
509 struct resource resources[2] = {};
510 char *str;
511 long long int base;
512 int processed, consumed = 0;
513 struct platform_device *pdev;
514
515 resources[0].flags = IORESOURCE_MEM;
516 resources[1].flags = IORESOURCE_IRQ;
517
518 resources[0].end = memparse(device, &str) - 1;
519
520 processed = sscanf(str, "@%lli:%u%n:%d%n",
521 &base, &resources[1].start, &consumed,
522 &vm_cmdline_id, &consumed);
523
524 if (processed < 2 || processed > 3 || str[consumed])
525 return -EINVAL;
526
527 resources[0].start = base;
528 resources[0].end += base;
529 resources[1].end = resources[1].start;
530
531 if (!vm_cmdline_parent_registered) {
532 err = device_register(&vm_cmdline_parent);
533 if (err) {
534 pr_err("Failed to register parent device!\n");
535 return err;
536 }
537 vm_cmdline_parent_registered = 1;
538 }
539
540 pr_info("Registering device virtio-mmio.%d at 0x%llx-0x%llx, IRQ %d.\n",
541 vm_cmdline_id,
542 (unsigned long long)resources[0].start,
543 (unsigned long long)resources[0].end,
544 (int)resources[1].start);
545
546 pdev = platform_device_register_resndata(&vm_cmdline_parent,
547 "virtio-mmio", vm_cmdline_id++,
548 resources, ARRAY_SIZE(resources), NULL, 0);
549 if (IS_ERR(pdev))
550 return PTR_ERR(pdev);
551
552 return 0;
553 }
554
555 static int vm_cmdline_get_device(struct device *dev, void *data)
556 {
557 char *buffer = data;
558 unsigned int len = strlen(buffer);
559 struct platform_device *pdev = to_platform_device(dev);
560
561 snprintf(buffer + len, PAGE_SIZE - len, "0x%llx@0x%llx:%llu:%d\n",
562 pdev->resource[0].end - pdev->resource[0].start + 1ULL,
563 (unsigned long long)pdev->resource[0].start,
564 (unsigned long long)pdev->resource[1].start,
565 pdev->id);
566 return 0;
567 }
568
569 static int vm_cmdline_get(char *buffer, const struct kernel_param *kp)
570 {
571 buffer[0] = '\0';
572 device_for_each_child(&vm_cmdline_parent, buffer,
573 vm_cmdline_get_device);
574 return strlen(buffer) + 1;
575 }
576
577 static struct kernel_param_ops vm_cmdline_param_ops = {
578 .set = vm_cmdline_set,
579 .get = vm_cmdline_get,
580 };
581
582 device_param_cb(device, &vm_cmdline_param_ops, NULL, S_IRUSR);
583
584 static int vm_unregister_cmdline_device(struct device *dev,
585 void *data)
586 {
587 platform_device_unregister(to_platform_device(dev));
588
589 return 0;
590 }
591
592 static void vm_unregister_cmdline_devices(void)
593 {
594 if (vm_cmdline_parent_registered) {
595 device_for_each_child(&vm_cmdline_parent, NULL,
596 vm_unregister_cmdline_device);
597 device_unregister(&vm_cmdline_parent);
598 vm_cmdline_parent_registered = 0;
599 }
600 }
601
602 #else
603
604 static void vm_unregister_cmdline_devices(void)
605 {
606 }
607
608 #endif
609
610 /* Platform driver */
611
612 static struct of_device_id virtio_mmio_match[] = {
613 { .compatible = "virtio,mmio", },
614 {},
615 };
616 MODULE_DEVICE_TABLE(of, virtio_mmio_match);
617
618 static struct platform_driver virtio_mmio_driver = {
619 .probe = virtio_mmio_probe,
620 .remove = __devexit_p(virtio_mmio_remove),
621 .driver = {
622 .name = "virtio-mmio",
623 .owner = THIS_MODULE,
624 .of_match_table = virtio_mmio_match,
625 },
626 };
627
628 static int __init virtio_mmio_init(void)
629 {
630 return platform_driver_register(&virtio_mmio_driver);
631 }
632
633 static void __exit virtio_mmio_exit(void)
634 {
635 platform_driver_unregister(&virtio_mmio_driver);
636 vm_unregister_cmdline_devices();
637 }
638
639 module_init(virtio_mmio_init);
640 module_exit(virtio_mmio_exit);
641
642 MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>");
643 MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices");
644 MODULE_LICENSE("GPL");
kernel source for telekom puls (alcatel/mediatek)