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				  u16 msix_vec)
120{
121	struct virtqueue *vq;
122	u16 num;
123	int err;
124
125	/* Select the queue we're interested in */
126	iowrite16(index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
127
128	/* Check if queue is either not available or already active. */
129	num = ioread16(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NUM);
130	if (!num || ioread32(vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN))
131		return ERR_PTR(-ENOENT);
132
133	info->msix_vector = msix_vec;
134
135	/* create the vring */
136	vq = vring_create_virtqueue(index, num,
137				    VIRTIO_PCI_VRING_ALIGN, &vp_dev->vdev,
138				    true, false, vp_notify, callback, name);
139	if (!vq)
140		return ERR_PTR(-ENOMEM);
141
142	/* activate the queue */
143	iowrite32(virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT,
144		  vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
145
146	vq->priv = (void __force *)vp_dev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
147
148	if (msix_vec != VIRTIO_MSI_NO_VECTOR) {
149		iowrite16(msix_vec, vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
150		msix_vec = ioread16(vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
151		if (msix_vec == VIRTIO_MSI_NO_VECTOR) {
152			err = -EBUSY;
153			goto out_deactivate;
154		}
155	}
156
157	return vq;
158
159out_deactivate:
160	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
161	vring_del_virtqueue(vq);
162	return ERR_PTR(err);
163}
164
165static void del_vq(struct virtio_pci_vq_info *info)
166{
167	struct virtqueue *vq = info->vq;
168	struct virtio_pci_device *vp_dev = to_vp_device(vq->vdev);
169
170	iowrite16(vq->index, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_SEL);
171
172	if (vp_dev->msix_enabled) {
173		iowrite16(VIRTIO_MSI_NO_VECTOR,
174			  vp_dev->ioaddr + VIRTIO_MSI_QUEUE_VECTOR);
175		/* Flush the write out to device */
176		ioread8(vp_dev->ioaddr + VIRTIO_PCI_ISR);
177	}
178
179	/* Select and deactivate the queue */
180	iowrite32(0, vp_dev->ioaddr + VIRTIO_PCI_QUEUE_PFN);
181
182	vring_del_virtqueue(vq);
183}
184
185static const struct virtio_config_ops virtio_pci_config_ops = {
186	.get		= vp_get,
187	.set		= vp_set,
188	.get_status	= vp_get_status,
189	.set_status	= vp_set_status,
190	.reset		= vp_reset,
191	.find_vqs	= vp_find_vqs,
192	.del_vqs	= vp_del_vqs,
193	.get_features	= vp_get_features,
194	.finalize_features = vp_finalize_features,
195	.bus_name	= vp_bus_name,
196	.set_vq_affinity = vp_set_vq_affinity,
197};
198
199/* the PCI probing function */
200int virtio_pci_legacy_probe(struct virtio_pci_device *vp_dev)
201{
202	struct pci_dev *pci_dev = vp_dev->pci_dev;
203	int rc;
204
205	/* We only own devices >= 0x1000 and <= 0x103f: leave the rest. */
206	if (pci_dev->device < 0x1000 || pci_dev->device > 0x103f)
207		return -ENODEV;
208
209	if (pci_dev->revision != VIRTIO_PCI_ABI_VERSION) {
210		printk(KERN_ERR "virtio_pci: expected ABI version %d, got %d\n",
211		       VIRTIO_PCI_ABI_VERSION, pci_dev->revision);
212		return -ENODEV;
213	}
214
215	rc = dma_set_mask_and_coherent(&pci_dev->dev, DMA_BIT_MASK(64));
216	if (rc)
217		rc = dma_set_mask_and_coherent(&pci_dev->dev,
218						DMA_BIT_MASK(32));
219	if (rc)
220		dev_warn(&pci_dev->dev, "Failed to enable 64-bit or 32-bit DMA.  Trying to continue, but this might not work.\n");
221
222	rc = pci_request_region(pci_dev, 0, "virtio-pci-legacy");
223	if (rc)
224		return rc;
225
226	rc = -ENOMEM;
227	vp_dev->ioaddr = pci_iomap(pci_dev, 0, 0);
228	if (!vp_dev->ioaddr)
229		goto err_iomap;
230
231	vp_dev->isr = vp_dev->ioaddr + VIRTIO_PCI_ISR;
232
233	/* we use the subsystem vendor/device id as the virtio vendor/device
234	 * id.  this allows us to use the same PCI vendor/device id for all
235	 * virtio devices and to identify the particular virtio driver by
236	 * the subsystem ids */
237	vp_dev->vdev.id.vendor = pci_dev->subsystem_vendor;
238	vp_dev->vdev.id.device = pci_dev->subsystem_device;
239
240	vp_dev->vdev.config = &virtio_pci_config_ops;
241
242	vp_dev->config_vector = vp_config_vector;
243	vp_dev->setup_vq = setup_vq;
244	vp_dev->del_vq = del_vq;
245
246	return 0;
247
248err_iomap:
249	pci_release_region(pci_dev, 0);
250	return rc;
251}
252
253void virtio_pci_legacy_remove(struct virtio_pci_device *vp_dev)
254{
255	struct pci_dev *pci_dev = vp_dev->pci_dev;
256
257	pci_iounmap(pci_dev, vp_dev->ioaddr);
258	pci_release_region(pci_dev, 0);
259}