Pawel Moll | edfd52e | 2011-10-24 14:07:03 +0100 | [diff] [blame] | 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 | * Registers layout (all 32-bit wide): |
| 10 | * |
| 11 | * offset d. name description |
| 12 | * ------ -- ---------------- ----------------- |
| 13 | * |
| 14 | * 0x000 R MagicValue Magic value "virt" |
| 15 | * 0x004 R Version Device version (current max. 1) |
| 16 | * 0x008 R DeviceID Virtio device ID |
| 17 | * 0x00c R VendorID Virtio vendor ID |
| 18 | * |
| 19 | * 0x010 R HostFeatures Features supported by the host |
| 20 | * 0x014 W HostFeaturesSel Set of host features to access via HostFeatures |
| 21 | * |
| 22 | * 0x020 W GuestFeatures Features activated by the guest |
| 23 | * 0x024 W GuestFeaturesSel Set of activated features to set via GuestFeatures |
| 24 | * 0x028 W GuestPageSize Size of guest's memory page in bytes |
| 25 | * |
| 26 | * 0x030 W QueueSel Queue selector |
| 27 | * 0x034 R QueueNumMax Maximum size of the currently selected queue |
| 28 | * 0x038 W QueueNum Queue size for the currently selected queue |
| 29 | * 0x03c W QueueAlign Used Ring alignment for the current queue |
| 30 | * 0x040 RW QueuePFN PFN for the currently selected queue |
| 31 | * |
| 32 | * 0x050 W QueueNotify Queue notifier |
| 33 | * 0x060 R InterruptStatus Interrupt status register |
| 34 | * 0x060 W InterruptACK Interrupt acknowledge register |
| 35 | * 0x070 RW Status Device status register |
| 36 | * |
| 37 | * 0x100+ RW Device-specific configuration space |
| 38 | * |
| 39 | * Based on Virtio PCI driver by Anthony Liguori, copyright IBM Corp. 2007 |
| 40 | * |
| 41 | * This work is licensed under the terms of the GNU GPL, version 2 or later. |
| 42 | * See the COPYING file in the top-level directory. |
| 43 | */ |
| 44 | |
| 45 | #include <linux/highmem.h> |
| 46 | #include <linux/interrupt.h> |
| 47 | #include <linux/io.h> |
| 48 | #include <linux/list.h> |
| 49 | #include <linux/module.h> |
| 50 | #include <linux/platform_device.h> |
| 51 | #include <linux/slab.h> |
| 52 | #include <linux/spinlock.h> |
| 53 | #include <linux/virtio.h> |
| 54 | #include <linux/virtio_config.h> |
| 55 | #include <linux/virtio_mmio.h> |
| 56 | #include <linux/virtio_ring.h> |
| 57 | |
| 58 | |
| 59 | |
| 60 | /* The alignment to use between consumer and producer parts of vring. |
| 61 | * Currently hardcoded to the page size. */ |
| 62 | #define VIRTIO_MMIO_VRING_ALIGN PAGE_SIZE |
| 63 | |
| 64 | |
| 65 | |
| 66 | #define to_virtio_mmio_device(_plat_dev) \ |
| 67 | container_of(_plat_dev, struct virtio_mmio_device, vdev) |
| 68 | |
| 69 | struct virtio_mmio_device { |
| 70 | struct virtio_device vdev; |
| 71 | struct platform_device *pdev; |
| 72 | |
| 73 | void __iomem *base; |
| 74 | unsigned long version; |
| 75 | |
| 76 | /* a list of queues so we can dispatch IRQs */ |
| 77 | spinlock_t lock; |
| 78 | struct list_head virtqueues; |
| 79 | }; |
| 80 | |
| 81 | struct virtio_mmio_vq_info { |
| 82 | /* the actual virtqueue */ |
| 83 | struct virtqueue *vq; |
| 84 | |
| 85 | /* the number of entries in the queue */ |
| 86 | unsigned int num; |
| 87 | |
| 88 | /* the index of the queue */ |
| 89 | int queue_index; |
| 90 | |
| 91 | /* the virtual address of the ring queue */ |
| 92 | void *queue; |
| 93 | |
| 94 | /* the list node for the virtqueues list */ |
| 95 | struct list_head node; |
| 96 | }; |
| 97 | |
| 98 | |
| 99 | |
| 100 | /* Configuration interface */ |
| 101 | |
| 102 | static u32 vm_get_features(struct virtio_device *vdev) |
| 103 | { |
| 104 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 105 | |
| 106 | /* TODO: Features > 32 bits */ |
| 107 | writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL); |
| 108 | |
| 109 | return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES); |
| 110 | } |
| 111 | |
| 112 | static void vm_finalize_features(struct virtio_device *vdev) |
| 113 | { |
| 114 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 115 | int i; |
| 116 | |
| 117 | /* Give virtio_ring a chance to accept features. */ |
| 118 | vring_transport_features(vdev); |
| 119 | |
| 120 | for (i = 0; i < ARRAY_SIZE(vdev->features); i++) { |
Sasha Levin | fe1a7fe | 2011-11-15 16:17:18 +0200 | [diff] [blame] | 121 | writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL); |
Pawel Moll | edfd52e | 2011-10-24 14:07:03 +0100 | [diff] [blame] | 122 | writel(vdev->features[i], |
| 123 | vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES); |
| 124 | } |
| 125 | } |
| 126 | |
| 127 | static void vm_get(struct virtio_device *vdev, unsigned offset, |
| 128 | void *buf, unsigned len) |
| 129 | { |
| 130 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 131 | u8 *ptr = buf; |
| 132 | int i; |
| 133 | |
| 134 | for (i = 0; i < len; i++) |
| 135 | ptr[i] = readb(vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); |
| 136 | } |
| 137 | |
| 138 | static void vm_set(struct virtio_device *vdev, unsigned offset, |
| 139 | const void *buf, unsigned len) |
| 140 | { |
| 141 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 142 | const u8 *ptr = buf; |
| 143 | int i; |
| 144 | |
| 145 | for (i = 0; i < len; i++) |
| 146 | writeb(ptr[i], vm_dev->base + VIRTIO_MMIO_CONFIG + offset + i); |
| 147 | } |
| 148 | |
| 149 | static u8 vm_get_status(struct virtio_device *vdev) |
| 150 | { |
| 151 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 152 | |
| 153 | return readl(vm_dev->base + VIRTIO_MMIO_STATUS) & 0xff; |
| 154 | } |
| 155 | |
| 156 | static void vm_set_status(struct virtio_device *vdev, u8 status) |
| 157 | { |
| 158 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 159 | |
| 160 | /* We should never be setting status to 0. */ |
| 161 | BUG_ON(status == 0); |
| 162 | |
| 163 | writel(status, vm_dev->base + VIRTIO_MMIO_STATUS); |
| 164 | } |
| 165 | |
| 166 | static void vm_reset(struct virtio_device *vdev) |
| 167 | { |
| 168 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 169 | |
| 170 | /* 0 status means a reset. */ |
| 171 | writel(0, vm_dev->base + VIRTIO_MMIO_STATUS); |
| 172 | } |
| 173 | |
| 174 | |
| 175 | |
| 176 | /* Transport interface */ |
| 177 | |
| 178 | /* the notify function used when creating a virt queue */ |
| 179 | static void vm_notify(struct virtqueue *vq) |
| 180 | { |
| 181 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); |
| 182 | struct virtio_mmio_vq_info *info = vq->priv; |
| 183 | |
| 184 | /* We write the queue's selector into the notification register to |
| 185 | * signal the other end */ |
| 186 | writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_NOTIFY); |
| 187 | } |
| 188 | |
| 189 | /* Notify all virtqueues on an interrupt. */ |
| 190 | static irqreturn_t vm_interrupt(int irq, void *opaque) |
| 191 | { |
| 192 | struct virtio_mmio_device *vm_dev = opaque; |
| 193 | struct virtio_mmio_vq_info *info; |
| 194 | struct virtio_driver *vdrv = container_of(vm_dev->vdev.dev.driver, |
| 195 | struct virtio_driver, driver); |
| 196 | unsigned long status; |
| 197 | unsigned long flags; |
| 198 | irqreturn_t ret = IRQ_NONE; |
| 199 | |
| 200 | /* Read and acknowledge interrupts */ |
| 201 | status = readl(vm_dev->base + VIRTIO_MMIO_INTERRUPT_STATUS); |
| 202 | writel(status, vm_dev->base + VIRTIO_MMIO_INTERRUPT_ACK); |
| 203 | |
| 204 | if (unlikely(status & VIRTIO_MMIO_INT_CONFIG) |
| 205 | && vdrv && vdrv->config_changed) { |
| 206 | vdrv->config_changed(&vm_dev->vdev); |
| 207 | ret = IRQ_HANDLED; |
| 208 | } |
| 209 | |
| 210 | if (likely(status & VIRTIO_MMIO_INT_VRING)) { |
| 211 | spin_lock_irqsave(&vm_dev->lock, flags); |
| 212 | list_for_each_entry(info, &vm_dev->virtqueues, node) |
| 213 | ret |= vring_interrupt(irq, info->vq); |
| 214 | spin_unlock_irqrestore(&vm_dev->lock, flags); |
| 215 | } |
| 216 | |
| 217 | return ret; |
| 218 | } |
| 219 | |
| 220 | |
| 221 | |
| 222 | static void vm_del_vq(struct virtqueue *vq) |
| 223 | { |
| 224 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vq->vdev); |
| 225 | struct virtio_mmio_vq_info *info = vq->priv; |
| 226 | unsigned long flags, size; |
| 227 | |
| 228 | spin_lock_irqsave(&vm_dev->lock, flags); |
| 229 | list_del(&info->node); |
| 230 | spin_unlock_irqrestore(&vm_dev->lock, flags); |
| 231 | |
| 232 | vring_del_virtqueue(vq); |
| 233 | |
| 234 | /* Select and deactivate the queue */ |
| 235 | writel(info->queue_index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); |
| 236 | writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); |
| 237 | |
| 238 | size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); |
| 239 | free_pages_exact(info->queue, size); |
| 240 | kfree(info); |
| 241 | } |
| 242 | |
| 243 | static void vm_del_vqs(struct virtio_device *vdev) |
| 244 | { |
| 245 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 246 | struct virtqueue *vq, *n; |
| 247 | |
| 248 | list_for_each_entry_safe(vq, n, &vdev->vqs, list) |
| 249 | vm_del_vq(vq); |
| 250 | |
| 251 | free_irq(platform_get_irq(vm_dev->pdev, 0), vm_dev); |
| 252 | } |
| 253 | |
| 254 | |
| 255 | |
| 256 | static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, |
| 257 | void (*callback)(struct virtqueue *vq), |
| 258 | const char *name) |
| 259 | { |
| 260 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 261 | struct virtio_mmio_vq_info *info; |
| 262 | struct virtqueue *vq; |
| 263 | unsigned long flags, size; |
| 264 | int err; |
| 265 | |
| 266 | /* Select the queue we're interested in */ |
| 267 | writel(index, vm_dev->base + VIRTIO_MMIO_QUEUE_SEL); |
| 268 | |
| 269 | /* Queue shouldn't already be set up. */ |
| 270 | if (readl(vm_dev->base + VIRTIO_MMIO_QUEUE_PFN)) { |
| 271 | err = -ENOENT; |
| 272 | goto error_available; |
| 273 | } |
| 274 | |
| 275 | /* Allocate and fill out our active queue description */ |
| 276 | info = kmalloc(sizeof(*info), GFP_KERNEL); |
| 277 | if (!info) { |
| 278 | err = -ENOMEM; |
| 279 | goto error_kmalloc; |
| 280 | } |
| 281 | info->queue_index = index; |
| 282 | |
| 283 | /* Allocate pages for the queue - start with a queue as big as |
| 284 | * possible (limited by maximum size allowed by device), drop down |
| 285 | * to a minimal size, just big enough to fit descriptor table |
| 286 | * and two rings (which makes it "alignment_size * 2") |
| 287 | */ |
| 288 | info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); |
| 289 | while (1) { |
| 290 | size = PAGE_ALIGN(vring_size(info->num, |
| 291 | VIRTIO_MMIO_VRING_ALIGN)); |
| 292 | /* Already smallest possible allocation? */ |
| 293 | if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) { |
| 294 | err = -ENOMEM; |
| 295 | goto error_alloc_pages; |
| 296 | } |
| 297 | |
| 298 | info->queue = alloc_pages_exact(size, GFP_KERNEL | __GFP_ZERO); |
| 299 | if (info->queue) |
| 300 | break; |
| 301 | |
| 302 | info->num /= 2; |
| 303 | } |
| 304 | |
| 305 | /* Activate the queue */ |
| 306 | writel(info->num, vm_dev->base + VIRTIO_MMIO_QUEUE_NUM); |
| 307 | writel(VIRTIO_MMIO_VRING_ALIGN, |
| 308 | vm_dev->base + VIRTIO_MMIO_QUEUE_ALIGN); |
| 309 | writel(virt_to_phys(info->queue) >> PAGE_SHIFT, |
| 310 | vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); |
| 311 | |
| 312 | /* Create the vring */ |
| 313 | vq = vring_new_virtqueue(info->num, VIRTIO_MMIO_VRING_ALIGN, |
| 314 | vdev, info->queue, vm_notify, callback, name); |
| 315 | if (!vq) { |
| 316 | err = -ENOMEM; |
| 317 | goto error_new_virtqueue; |
| 318 | } |
| 319 | |
| 320 | vq->priv = info; |
| 321 | info->vq = vq; |
| 322 | |
| 323 | spin_lock_irqsave(&vm_dev->lock, flags); |
| 324 | list_add(&info->node, &vm_dev->virtqueues); |
| 325 | spin_unlock_irqrestore(&vm_dev->lock, flags); |
| 326 | |
| 327 | return vq; |
| 328 | |
| 329 | error_new_virtqueue: |
| 330 | writel(0, vm_dev->base + VIRTIO_MMIO_QUEUE_PFN); |
| 331 | free_pages_exact(info->queue, size); |
| 332 | error_alloc_pages: |
| 333 | kfree(info); |
| 334 | error_kmalloc: |
| 335 | error_available: |
| 336 | return ERR_PTR(err); |
| 337 | } |
| 338 | |
| 339 | static int vm_find_vqs(struct virtio_device *vdev, unsigned nvqs, |
| 340 | struct virtqueue *vqs[], |
| 341 | vq_callback_t *callbacks[], |
| 342 | const char *names[]) |
| 343 | { |
| 344 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
| 345 | unsigned int irq = platform_get_irq(vm_dev->pdev, 0); |
| 346 | int i, err; |
| 347 | |
| 348 | err = request_irq(irq, vm_interrupt, IRQF_SHARED, |
| 349 | dev_name(&vdev->dev), vm_dev); |
| 350 | if (err) |
| 351 | return err; |
| 352 | |
| 353 | for (i = 0; i < nvqs; ++i) { |
| 354 | vqs[i] = vm_setup_vq(vdev, i, callbacks[i], names[i]); |
| 355 | if (IS_ERR(vqs[i])) { |
| 356 | vm_del_vqs(vdev); |
| 357 | return PTR_ERR(vqs[i]); |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | return 0; |
| 362 | } |
| 363 | |
Rick Jones | 6684604 | 2011-11-14 14:17:08 +0000 | [diff] [blame] | 364 | static const char *vm_bus_name(struct virtio_device *vdev) |
| 365 | { |
| 366 | struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev); |
Pawel Moll | edfd52e | 2011-10-24 14:07:03 +0100 | [diff] [blame] | 367 | |
Rick Jones | 6684604 | 2011-11-14 14:17:08 +0000 | [diff] [blame] | 368 | return vm_dev->pdev->name; |
| 369 | } |
Pawel Moll | edfd52e | 2011-10-24 14:07:03 +0100 | [diff] [blame] | 370 | |
| 371 | static struct virtio_config_ops virtio_mmio_config_ops = { |
| 372 | .get = vm_get, |
| 373 | .set = vm_set, |
| 374 | .get_status = vm_get_status, |
| 375 | .set_status = vm_set_status, |
| 376 | .reset = vm_reset, |
| 377 | .find_vqs = vm_find_vqs, |
| 378 | .del_vqs = vm_del_vqs, |
| 379 | .get_features = vm_get_features, |
| 380 | .finalize_features = vm_finalize_features, |
Rick Jones | 6684604 | 2011-11-14 14:17:08 +0000 | [diff] [blame] | 381 | .bus_name = vm_bus_name, |
Pawel Moll | edfd52e | 2011-10-24 14:07:03 +0100 | [diff] [blame] | 382 | }; |
| 383 | |
| 384 | |
| 385 | |
| 386 | /* Platform device */ |
| 387 | |
| 388 | static int __devinit virtio_mmio_probe(struct platform_device *pdev) |
| 389 | { |
| 390 | struct virtio_mmio_device *vm_dev; |
| 391 | struct resource *mem; |
| 392 | unsigned long magic; |
| 393 | |
| 394 | mem = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 395 | if (!mem) |
| 396 | return -EINVAL; |
| 397 | |
| 398 | if (!devm_request_mem_region(&pdev->dev, mem->start, |
| 399 | resource_size(mem), pdev->name)) |
| 400 | return -EBUSY; |
| 401 | |
| 402 | vm_dev = devm_kzalloc(&pdev->dev, sizeof(*vm_dev), GFP_KERNEL); |
| 403 | if (!vm_dev) |
| 404 | return -ENOMEM; |
| 405 | |
| 406 | vm_dev->vdev.dev.parent = &pdev->dev; |
| 407 | vm_dev->vdev.config = &virtio_mmio_config_ops; |
| 408 | vm_dev->pdev = pdev; |
| 409 | INIT_LIST_HEAD(&vm_dev->virtqueues); |
| 410 | spin_lock_init(&vm_dev->lock); |
| 411 | |
| 412 | vm_dev->base = devm_ioremap(&pdev->dev, mem->start, resource_size(mem)); |
| 413 | if (vm_dev->base == NULL) |
| 414 | return -EFAULT; |
| 415 | |
| 416 | /* Check magic value */ |
| 417 | magic = readl(vm_dev->base + VIRTIO_MMIO_MAGIC_VALUE); |
| 418 | if (memcmp(&magic, "virt", 4) != 0) { |
| 419 | dev_warn(&pdev->dev, "Wrong magic value 0x%08lx!\n", magic); |
| 420 | return -ENODEV; |
| 421 | } |
| 422 | |
| 423 | /* Check device version */ |
| 424 | vm_dev->version = readl(vm_dev->base + VIRTIO_MMIO_VERSION); |
| 425 | if (vm_dev->version != 1) { |
| 426 | dev_err(&pdev->dev, "Version %ld not supported!\n", |
| 427 | vm_dev->version); |
| 428 | return -ENXIO; |
| 429 | } |
| 430 | |
| 431 | vm_dev->vdev.id.device = readl(vm_dev->base + VIRTIO_MMIO_DEVICE_ID); |
| 432 | vm_dev->vdev.id.vendor = readl(vm_dev->base + VIRTIO_MMIO_VENDOR_ID); |
| 433 | |
| 434 | writel(PAGE_SIZE, vm_dev->base + VIRTIO_MMIO_GUEST_PAGE_SIZE); |
| 435 | |
| 436 | platform_set_drvdata(pdev, vm_dev); |
| 437 | |
| 438 | return register_virtio_device(&vm_dev->vdev); |
| 439 | } |
| 440 | |
| 441 | static int __devexit virtio_mmio_remove(struct platform_device *pdev) |
| 442 | { |
| 443 | struct virtio_mmio_device *vm_dev = platform_get_drvdata(pdev); |
| 444 | |
| 445 | unregister_virtio_device(&vm_dev->vdev); |
| 446 | |
| 447 | return 0; |
| 448 | } |
| 449 | |
| 450 | |
| 451 | |
| 452 | /* Platform driver */ |
| 453 | |
| 454 | static struct of_device_id virtio_mmio_match[] = { |
| 455 | { .compatible = "virtio,mmio", }, |
| 456 | {}, |
| 457 | }; |
| 458 | MODULE_DEVICE_TABLE(of, virtio_mmio_match); |
| 459 | |
| 460 | static struct platform_driver virtio_mmio_driver = { |
| 461 | .probe = virtio_mmio_probe, |
| 462 | .remove = __devexit_p(virtio_mmio_remove), |
| 463 | .driver = { |
| 464 | .name = "virtio-mmio", |
| 465 | .owner = THIS_MODULE, |
| 466 | .of_match_table = virtio_mmio_match, |
| 467 | }, |
| 468 | }; |
| 469 | |
| 470 | static int __init virtio_mmio_init(void) |
| 471 | { |
| 472 | return platform_driver_register(&virtio_mmio_driver); |
| 473 | } |
| 474 | |
| 475 | static void __exit virtio_mmio_exit(void) |
| 476 | { |
| 477 | platform_driver_unregister(&virtio_mmio_driver); |
| 478 | } |
| 479 | |
| 480 | module_init(virtio_mmio_init); |
| 481 | module_exit(virtio_mmio_exit); |
| 482 | |
| 483 | MODULE_AUTHOR("Pawel Moll <pawel.moll@arm.com>"); |
| 484 | MODULE_DESCRIPTION("Platform bus driver for memory mapped virtio devices"); |
| 485 | MODULE_LICENSE("GPL"); |