1/*
  2 * Virtio PCI driver - legacy device support
  3 *
  4 * This module allows virtio devices to be used over a virtual PCI device.
  5 * This can be used with QEMU based VMMs like KVM or Xen.
  6 *
  7 * Copyright IBM Corp. 2007
  8 * Copyright Red Hat, Inc. 2014
  9 *
 10 * Authors:
 11 *  Anthony Liguori  <aliguori@us.ibm.com>
 12 *  Rusty Russell <rusty@rustcorp.com.au>
 13 *  Michael S. Tsirkin <mst@redhat.com>
 14 *
 15 * This work is licensed under the terms of the GNU GPL, version 2 or later.
 16 * See the COPYING file in the top-level directory.
 17 *
 18 */
 19
 20#include "virtio_pci_common.h"
 21
 22/* virtio config->get_features() implementation */
 23static u64 vp_get_features(struct virtio_device *vdev)
 24{
 25	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 26
 27	/* When someone needs more than 32 feature bits, we'll need to
 28	 * steal a bit to indicate that the rest are somewhere else. */
 29	return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
 30}
 31
 32/* virtio config->finalize_features() implementation */
 33static int vp_finalize_features(struct virtio_device *vdev)
 34{
 35	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 36
 37	/* Give virtio_ring a chance to accept features. */
 38	vring_transport_features(vdev);
 39
 40	/* Make sure we don't have any features > 32 bits! */
 41	BUG_ON((u32)vdev->features != vdev->features);
 42
 43	/* We only support 32 feature bits. */
 44	iowrite32(vdev->features, vp_dev->ioaddr + VIRTIO_PCI_GUEST_FEATURES);
 45
 46	return 0;
 47}
 48
 49/* virtio config->get() implementation */
 50static void vp_get(struct virtio_device *vdev, unsigned offset,
 51		   void *buf, unsigned len)
 52{
 53	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 54	void __iomem *ioaddr = vp_dev->ioaddr +
 55				VIRTIO_PCI_CONFIG(vp_dev) + offset;
 56	u8 *ptr = buf;
 57	int i;
 58
 59	for (i = 0; i < len; i++)
 60		ptr[i] = ioread8(ioaddr + i);
 61}
 62
 63/* the config->set() implementation.  it's symmetric to the config->get()
 64 * implementation */
 65static void vp_set(struct virtio_device *vdev, unsigned offset,
 66		   const void *buf, unsigned len)
 67{
 68	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 69	void __iomem *ioaddr = vp_dev->ioaddr +
 70				VIRTIO_PCI_CONFIG(vp_dev) + offset;
 71	const u8 *ptr = buf;
 72	int i;
 73
 74	for (i = 0; i < len; i++)
 75		iowrite8(ptr[i], ioaddr + i);
 76}
 77
 78/* config->{get,set}_status() implementations */
 79static u8 vp_get_status(struct virtio_device *vdev)
 80{
 81	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 82	return ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 83}
 84
 85static void vp_set_status(struct virtio_device *vdev, u8 status)
 86{
 87	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 88	/* We should never be setting status to 0. */
 89	BUG_ON(status == 0);
 90	iowrite8(status, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 91}
 92
 93static void vp_reset(struct virtio_device *vdev)
 94{
 95	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 96	/* 0 status means a reset. */
 97	iowrite8(0, vp_dev->ioaddr + VIRTIO_PCI_STATUS);
 98	/* Flush out the status write, and flush in device writes,
 99	 * including MSi-X interrupts, if any. */
100	ioread8(vp_dev->ioaddr + VIRTIO_PCI_STATUS);
101	/* Flush pending VQ/configuration callbacks. */
102	vp_synchronize_vectors(vdev);
103}
104
105static u16 vp_config_vector(struct virtio_pci_device *vp_dev, u16 vector)
106{
107	/* Setup the vector used for configuration events */
108	iowrite16(vector, vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
109	/* Verify we had enough resources to assign the vector */
110	/* Will also flush the write out to device */
111	return ioread16(vp_dev->ioaddr + VIRTIO_MSI_CONFIG_VECTOR);
112}
113
114static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
115				  struct virtio_pci_vq_info *info,
116				  unsigned index,
117				  void (*callback)(struct virtqueue *vq),
118				  const char *name,
119				  bool ctx,
120				  u16 msix_vec)
121{
122	struct virtqueue *vq;
123	u16 num;
124	int err;
125
126	/* Select the queue we're interested in */
127	iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
128
129	/* Check if queue is either not available or already active. */
130	num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
131	if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
132		return ERR_PTR(-ENOENT);
133
134	info->msix_vector = msix_vec;
135
136	/* create the vring */
137	vq = vring_create_virtqueue(index, num,
138				    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
139				    true, false, ctx,
140				    vp_notify, callback, name);
141	if (!vq)
142		return ERR_PTR(-ENOMEM);
143
144	/* activate the queue */
145	iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
146		  vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
147
148	vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
149
150	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
151		iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
152		msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
153		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
154			err = -EBUSY;
155			goto out_deactivate;
156		}
157	}
158
159	return vq;
160
161out_deactivate:
162	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
163	vring_del_virtqueue(vq);
164	return ERR_PTR(err);
165}
166
167static void del_vq(struct virtio_pci_vq_info *info)
168{
169	struct virtqueue *vq = info->vq;
170	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
171
172	iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
173
174	if (vp_dev->msix_enabled) {
175		iowrite16(VIRTIO_MSI_NO_VECTOR,
176			  vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
177		/* Flush the write out to device */
178		ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
179	}
180
181	/* Select and deactivate the queue */
182	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
183
184	vring_del_virtqueue(vq);
185}
186
187static const struct virtio_config_ops virtio_pci_config_ops = {
188	.get		= vp_get,
189	.set		= vp_set,
190	.get_status	= vp_get_status,
191	.set_status	= vp_set_status,
192	.reset		= vp_reset,
193	.find_vqs	= vp_find_vqs,
194	.del_vqs	= vp_del_vqs,
195	.get_features	= vp_get_features,
196	.finalize_features = vp_finalize_features,
197	.bus_name	= vp_bus_name,
198	.set_vq_affinity = vp_set_vq_affinity,
199	.get_vq_affinity = vp_get_vq_affinity,
200};
201
202/* the PCI probing function */
203int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
204{
205	struct pci_dev *pci_dev = vp_dev->pci_dev;
206	int rc;
207
208	/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
209	if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
210		return -ENODEV;
211
212	if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
213		printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
214		       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
215		return -ENODEV;
216	}
217
218	rc = dma_set_mask(&pci_dev->dev, DMA_BIT_MASK(64));
219	if (rc) {
220		rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(32));
221	} else {
222		/*
223		 * The virtio ring base address is expressed as a 32-bit PFN,
224		 * with a page size of 1 << VIRTIO_PCI_QUEUE_ADDR_SHIFT.
225		 */
226		dma_set_coherent_mask(&pci_dev->dev,
227				DMA_BIT_MASK(32 + VIRTIO_PCI_QUEUE_ADDR_SHIFT));
228	}
229
230	if (rc)
231		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
232
233	rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
234	if (rc)
235		return rc;
236
237	rc = -ENOMEM;
238	vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
239	if (!vp_dev->ioaddr)
240		goto err_iomap;
241
242	vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
243
244	/* we use the subsystem vendor/device id as the virtio vendor/device
245	 * id.  this allows us to use the same PCI vendor/device id for all
246	 * virtio devices and to identify the particular virtio driver by
247	 * the subsystem ids */
248	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
249	vp_dev->vdev.id.device = pci_dev->subsystem_device;
250
251	vp_dev->vdev.config = &virtio_pci_config_ops;
252
253	vp_dev->config_vector = vp_config_vector;
254	vp_dev->setup_vq = setup_vq;
255	vp_dev->del_vq = del_vq;
256
257	return 0;
258
259err_iomap:
260	pci_release_region(pci_dev, 0);
261	return rc;
262}
263
264void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
265{
266	struct pci_dev *pci_dev = vp_dev->pci_dev;
267
268	pci_iounmap(pci_dev, vp_dev->ioaddr);
269	pci_release_region(pci_dev, 0);
270}