first commit

1 files changed, 166 insertions, 0 deletions

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
new file mode 100644
index 000000000..29b910423
--- /dev/null
+++ b/include/linux/virtio_config.h
@@ -0,0 +1,166 @@
+#ifndef _LINUX_VIRTIO_CONFIG_H
+#define _LINUX_VIRTIO_CONFIG_H
+
+#include <linux/err.h>
+#include <linux/bug.h>
+#include <linux/virtio.h>
+#include <uapi/linux/virtio_config.h>
+
+/**
+ * virtio_config_ops - operations for configuring a virtio device
+ * @get: read the value of a configuration field
+ *	vdev: the virtio_device
+ *	offset: the offset of the configuration field
+ *	buf: the buffer to write the field value into.
+ *	len: the length of the buffer
+ * @set: write the value of a configuration field
+ *	vdev: the virtio_device
+ *	offset: the offset of the configuration field
+ *	buf: the buffer to read the field value from.
+ *	len: the length of the buffer
+ * @get_status: read the status byte
+ *	vdev: the virtio_device
+ *	Returns the status byte
+ * @set_status: write the status byte
+ *	vdev: the virtio_device
+ *	status: the new status byte
+ * @reset: reset the device
+ *	vdev: the virtio device
+ *	After this, status and feature negotiation must be done again
+ *	Device must not be reset from its vq/config callbacks, or in
+ *	parallel with being added/removed.
+ * @find_vqs: find virtqueues and instantiate them.
+ *	vdev: the virtio_device
+ *	nvqs: the number of virtqueues to find
+ *	vqs: on success, includes new virtqueues
+ *	callbacks: array of callbacks, for each virtqueue
+ *		include a NULL entry for vqs that do not need a callback
+ *	names: array of virtqueue names (mainly for debugging)
+ *		include a NULL entry for vqs unused by driver
+ *	Returns 0 on success or error status
+ * @del_vqs: free virtqueues found by find_vqs().
+ * @get_features: get the array of feature bits for this device.
+ *	vdev: the virtio_device
+ *	Returns the first 32 feature bits (all we currently need).
+ * @finalize_features: confirm what device features we'll be using.
+ *	vdev: the virtio_device
+ *	This gives the final feature bits for the device: it can change
+ *	the dev->feature bits if it wants.
+ * @bus_name: return the bus name associated with the device
+ *	vdev: the virtio_device
+ *      This returns a pointer to the bus name a la pci_name from which
+ *      the caller can then copy.
+ * @set_vq_affinity: set the affinity for a virtqueue.
+ */
+typedef void vq_callback_t(struct virtqueue *);
+struct virtio_config_ops {
+	void (*get)(struct virtio_device *vdev, unsigned offset,
+		    void *buf, unsigned len);
+	void (*set)(struct virtio_device *vdev, unsigned offset,
+		    const void *buf, unsigned len);
+	u8 (*get_status)(struct virtio_device *vdev);
+	void (*set_status)(struct virtio_device *vdev, u8 status);
+	void (*reset)(struct virtio_device *vdev);
+	int (*find_vqs)(struct virtio_device *, unsigned nvqs,
+			struct virtqueue *vqs[],
+			vq_callback_t *callbacks[],
+			const char *names[]);
+	void (*del_vqs)(struct virtio_device *);
+	u32 (*get_features)(struct virtio_device *vdev);
+	void (*finalize_features)(struct virtio_device *vdev);
+	const char *(*bus_name)(struct virtio_device *vdev);
+	int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
+};
+
+/* If driver didn't advertise the feature, it will never appear. */
+void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
+					 unsigned int fbit);
+
+/**
+ * virtio_has_feature - helper to determine if this device has this feature.
+ * @vdev: the device
+ * @fbit: the feature bit
+ */
+static inline bool virtio_has_feature(const struct virtio_device *vdev,
+				      unsigned int fbit)
+{
+	/* Did you forget to fix assumptions on max features? */
+	if (__builtin_constant_p(fbit))
+		BUILD_BUG_ON(fbit >= 32);
+	else
+		BUG_ON(fbit >= 32);
+
+	if (fbit < VIRTIO_TRANSPORT_F_START)
+		virtio_check_driver_offered_feature(vdev, fbit);
+
+	return test_bit(fbit, vdev->features);
+}
+
+/**
+ * virtio_config_val - look for a feature and get a virtio config entry.
+ * @vdev: the virtio device
+ * @fbit: the feature bit
+ * @offset: the type to search for.
+ * @v: a pointer to the value to fill in.
+ *
+ * The return value is -ENOENT if the feature doesn't exist.  Otherwise
+ * the config value is copied into whatever is pointed to by v. */
+#define virtio_config_val(vdev, fbit, offset, v) \
+	virtio_config_buf((vdev), (fbit), (offset), (v), sizeof(*v))
+
+#define virtio_config_val_len(vdev, fbit, offset, v, len) \
+	virtio_config_buf((vdev), (fbit), (offset), (v), (len))
+
+static inline int virtio_config_buf(struct virtio_device *vdev,
+				    unsigned int fbit,
+				    unsigned int offset,
+				    void *buf, unsigned len)
+{
+	if (!virtio_has_feature(vdev, fbit))
+		return -ENOENT;
+
+	vdev->config->get(vdev, offset, buf, len);
+	return 0;
+}
+
+static inline
+struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
+					vq_callback_t *c, const char *n)
+{
+	vq_callback_t *callbacks[] = { c };
+	const char *names[] = { n };
+	struct virtqueue *vq;
+	int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names);
+	if (err < 0)
+		return ERR_PTR(err);
+	return vq;
+}
+
+static inline
+const char *virtio_bus_name(struct virtio_device *vdev)
+{
+	if (!vdev->config->bus_name)
+		return "virtio";
+	return vdev->config->bus_name(vdev);
+}
+
+/**
+ * virtqueue_set_affinity - setting affinity for a virtqueue
+ * @vq: the virtqueue
+ * @cpu: the cpu no.
+ *
+ * Pay attention the function are best-effort: the affinity hint may not be set
+ * due to config support, irq type and sharing.
+ *
+ */
+static inline
+int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
+{
+	struct virtio_device *vdev = vq->vdev;
+	if (vdev->config->set_vq_affinity)
+		return vdev->config->set_vq_affinity(vq, cpu);
+	return 0;
+}
+
+
+#endif /* _LINUX_VIRTIO_CONFIG_H */