mirror of
https://github.com/AsahiLinux/u-boot
synced 2024-12-05 02:51:00 +00:00
321 lines
9.4 KiB
C
321 lines
9.4 KiB
C
|
/* SPDX-License-Identifier: BSD-3-Clause */
|
||
|
/*
|
||
|
* Copyright (C) 2018, Tuomas Tynkkynen <tuomas.tynkkynen@iki.fi>
|
||
|
* Copyright (C) 2018, Bin Meng <bmeng.cn@gmail.com>
|
||
|
*
|
||
|
* From Linux kernel include/uapi/linux/virtio_ring.h
|
||
|
*/
|
||
|
|
||
|
#ifndef _LINUX_VIRTIO_RING_H
|
||
|
#define _LINUX_VIRTIO_RING_H
|
||
|
|
||
|
#include <virtio_types.h>
|
||
|
|
||
|
/* This marks a buffer as continuing via the next field */
|
||
|
#define VRING_DESC_F_NEXT 1
|
||
|
/* This marks a buffer as write-only (otherwise read-only) */
|
||
|
#define VRING_DESC_F_WRITE 2
|
||
|
/* This means the buffer contains a list of buffer descriptors */
|
||
|
#define VRING_DESC_F_INDIRECT 4
|
||
|
|
||
|
/*
|
||
|
* The Host uses this in used->flags to advise the Guest: don't kick me when
|
||
|
* you add a buffer. It's unreliable, so it's simply an optimization. Guest
|
||
|
* will still kick if it's out of buffers.
|
||
|
*/
|
||
|
#define VRING_USED_F_NO_NOTIFY 1
|
||
|
|
||
|
/*
|
||
|
* The Guest uses this in avail->flags to advise the Host: don't interrupt me
|
||
|
* when you consume a buffer. It's unreliable, so it's simply an optimization.
|
||
|
*/
|
||
|
#define VRING_AVAIL_F_NO_INTERRUPT 1
|
||
|
|
||
|
/* We support indirect buffer descriptors */
|
||
|
#define VIRTIO_RING_F_INDIRECT_DESC 28
|
||
|
|
||
|
/*
|
||
|
* The Guest publishes the used index for which it expects an interrupt
|
||
|
* at the end of the avail ring. Host should ignore the avail->flags field.
|
||
|
*
|
||
|
* The Host publishes the avail index for which it expects a kick
|
||
|
* at the end of the used ring. Guest should ignore the used->flags field.
|
||
|
*/
|
||
|
#define VIRTIO_RING_F_EVENT_IDX 29
|
||
|
|
||
|
/* Virtio ring descriptors: 16 bytes. These can chain together via "next". */
|
||
|
struct vring_desc {
|
||
|
/* Address (guest-physical) */
|
||
|
__virtio64 addr;
|
||
|
/* Length */
|
||
|
__virtio32 len;
|
||
|
/* The flags as indicated above */
|
||
|
__virtio16 flags;
|
||
|
/* We chain unused descriptors via this, too */
|
||
|
__virtio16 next;
|
||
|
};
|
||
|
|
||
|
struct vring_avail {
|
||
|
__virtio16 flags;
|
||
|
__virtio16 idx;
|
||
|
__virtio16 ring[];
|
||
|
};
|
||
|
|
||
|
struct vring_used_elem {
|
||
|
/* Index of start of used descriptor chain */
|
||
|
__virtio32 id;
|
||
|
/* Total length of the descriptor chain which was used (written to) */
|
||
|
__virtio32 len;
|
||
|
};
|
||
|
|
||
|
struct vring_used {
|
||
|
__virtio16 flags;
|
||
|
__virtio16 idx;
|
||
|
struct vring_used_elem ring[];
|
||
|
};
|
||
|
|
||
|
struct vring {
|
||
|
unsigned int num;
|
||
|
struct vring_desc *desc;
|
||
|
struct vring_avail *avail;
|
||
|
struct vring_used *used;
|
||
|
};
|
||
|
|
||
|
/**
|
||
|
* virtqueue - a queue to register buffers for sending or receiving.
|
||
|
*
|
||
|
* @list: the chain of virtqueues for this device
|
||
|
* @vdev: the virtio device this queue was created for
|
||
|
* @index: the zero-based ordinal number for this queue
|
||
|
* @num_free: number of elements we expect to be able to fit
|
||
|
* @vring: actual memory layout for this queue
|
||
|
* @event: host publishes avail event idx
|
||
|
* @free_head: head of free buffer list
|
||
|
* @num_added: number we've added since last sync
|
||
|
* @last_used_idx: last used index we've seen
|
||
|
* @avail_flags_shadow: last written value to avail->flags
|
||
|
* @avail_idx_shadow: last written value to avail->idx in guest byte order
|
||
|
*/
|
||
|
struct virtqueue {
|
||
|
struct list_head list;
|
||
|
struct udevice *vdev;
|
||
|
unsigned int index;
|
||
|
unsigned int num_free;
|
||
|
struct vring vring;
|
||
|
bool event;
|
||
|
unsigned int free_head;
|
||
|
unsigned int num_added;
|
||
|
u16 last_used_idx;
|
||
|
u16 avail_flags_shadow;
|
||
|
u16 avail_idx_shadow;
|
||
|
};
|
||
|
|
||
|
/*
|
||
|
* Alignment requirements for vring elements.
|
||
|
* When using pre-virtio 1.0 layout, these fall out naturally.
|
||
|
*/
|
||
|
#define VRING_AVAIL_ALIGN_SIZE 2
|
||
|
#define VRING_USED_ALIGN_SIZE 4
|
||
|
#define VRING_DESC_ALIGN_SIZE 16
|
||
|
|
||
|
/*
|
||
|
* We publish the used event index at the end of the available ring,
|
||
|
* and vice versa. They are at the end for backwards compatibility.
|
||
|
*/
|
||
|
#define vring_used_event(vr) ((vr)->avail->ring[(vr)->num])
|
||
|
#define vring_avail_event(vr) (*(__virtio16 *)&(vr)->used->ring[(vr)->num])
|
||
|
|
||
|
static inline void vring_init(struct vring *vr, unsigned int num, void *p,
|
||
|
unsigned long align)
|
||
|
{
|
||
|
vr->num = num;
|
||
|
vr->desc = p;
|
||
|
vr->avail = p + num * sizeof(struct vring_desc);
|
||
|
vr->used = (void *)(((uintptr_t)&vr->avail->ring[num] +
|
||
|
sizeof(__virtio16) + align - 1) & ~(align - 1));
|
||
|
}
|
||
|
|
||
|
static inline unsigned int vring_size(unsigned int num, unsigned long align)
|
||
|
{
|
||
|
return ((sizeof(struct vring_desc) * num +
|
||
|
sizeof(__virtio16) * (3 + num) + align - 1) & ~(align - 1)) +
|
||
|
sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX.
|
||
|
* Assuming a given event_idx value from the other side, if we have just
|
||
|
* incremented index from old to new_idx, should we trigger an event?
|
||
|
*/
|
||
|
static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
|
||
|
{
|
||
|
/*
|
||
|
* Note: Xen has similar logic for notification hold-off
|
||
|
* in include/xen/interface/io/ring.h with req_event and req_prod
|
||
|
* corresponding to event_idx + 1 and new_idx respectively.
|
||
|
* Note also that req_event and req_prod in Xen start at 1,
|
||
|
* event indexes in virtio start at 0.
|
||
|
*/
|
||
|
return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
|
||
|
}
|
||
|
|
||
|
struct virtio_sg;
|
||
|
|
||
|
/**
|
||
|
* virtqueue_add - expose buffers to other end
|
||
|
*
|
||
|
* @vq: the struct virtqueue we're talking about
|
||
|
* @sgs: array of terminated scatterlists
|
||
|
* @out_sgs: the number of scatterlists readable by other side
|
||
|
* @in_sgs: the number of scatterlists which are writable
|
||
|
* (after readable ones)
|
||
|
*
|
||
|
* Caller must ensure we don't call this with other virtqueue operations
|
||
|
* at the same time (except where noted).
|
||
|
*
|
||
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
|
||
|
*/
|
||
|
int virtqueue_add(struct virtqueue *vq, struct virtio_sg *sgs[],
|
||
|
unsigned int out_sgs, unsigned int in_sgs);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_kick - update after add_buf
|
||
|
*
|
||
|
* @vq: the struct virtqueue
|
||
|
*
|
||
|
* After one or more virtqueue_add() calls, invoke this to kick
|
||
|
* the other side.
|
||
|
*
|
||
|
* Caller must ensure we don't call this with other virtqueue
|
||
|
* operations at the same time (except where noted).
|
||
|
*/
|
||
|
void virtqueue_kick(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_get_buf - get the next used buffer
|
||
|
*
|
||
|
* @vq: the struct virtqueue we're talking about
|
||
|
* @len: the length written into the buffer
|
||
|
*
|
||
|
* If the device wrote data into the buffer, @len will be set to the
|
||
|
* amount written. This means you don't need to clear the buffer
|
||
|
* beforehand to ensure there's no data leakage in the case of short
|
||
|
* writes.
|
||
|
*
|
||
|
* Caller must ensure we don't call this with other virtqueue
|
||
|
* operations at the same time (except where noted).
|
||
|
*
|
||
|
* Returns NULL if there are no used buffers, or the memory buffer
|
||
|
* handed to virtqueue_add_*().
|
||
|
*/
|
||
|
void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
|
||
|
|
||
|
/**
|
||
|
* vring_create_virtqueue - create a virtqueue for a virtio device
|
||
|
*
|
||
|
* @index: the index of the queue
|
||
|
* @num: number of elements of the queue
|
||
|
* @vring_align:the alignment requirement of the descriptor ring
|
||
|
* @udev: the virtio transport udevice
|
||
|
* @return: the virtqueue pointer or NULL if failed
|
||
|
*
|
||
|
* This creates a virtqueue and allocates the descriptor ring for a virtio
|
||
|
* device. The caller should query virtqueue_get_ring_size() to learn the
|
||
|
* actual size of the ring.
|
||
|
*
|
||
|
* This API is supposed to be called by the virtio transport driver in the
|
||
|
* virtio find_vqs() uclass method.
|
||
|
*/
|
||
|
struct virtqueue *vring_create_virtqueue(unsigned int index, unsigned int num,
|
||
|
unsigned int vring_align,
|
||
|
struct udevice *udev);
|
||
|
|
||
|
/**
|
||
|
* vring_del_virtqueue - destroy a virtqueue
|
||
|
*
|
||
|
* @vq: the struct virtqueue we're talking about
|
||
|
*
|
||
|
* This destroys a virtqueue. If created with vring_create_virtqueue(),
|
||
|
* this also frees the descriptor ring.
|
||
|
*
|
||
|
* This API is supposed to be called by the virtio transport driver in the
|
||
|
* virtio del_vqs() uclass method.
|
||
|
*/
|
||
|
void vring_del_virtqueue(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_get_vring_size - get the size of the virtqueue's vring
|
||
|
*
|
||
|
* @vq: the struct virtqueue containing the vring of interest
|
||
|
* @return: the size of the vring in a virtqueue.
|
||
|
*/
|
||
|
unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_get_desc_addr - get the vring descriptor table address
|
||
|
*
|
||
|
* @vq: the struct virtqueue containing the vring of interest
|
||
|
* @return: the descriptor table address of the vring in a virtqueue.
|
||
|
*/
|
||
|
ulong virtqueue_get_desc_addr(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_get_avail_addr - get the vring available ring address
|
||
|
*
|
||
|
* @vq: the struct virtqueue containing the vring of interest
|
||
|
* @return: the available ring address of the vring in a virtqueue.
|
||
|
*/
|
||
|
ulong virtqueue_get_avail_addr(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_get_used_addr - get the vring used ring address
|
||
|
*
|
||
|
* @vq: the struct virtqueue containing the vring of interest
|
||
|
* @return: the used ring address of the vring in a virtqueue.
|
||
|
*/
|
||
|
ulong virtqueue_get_used_addr(struct virtqueue *vq);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_poll - query pending used buffers
|
||
|
*
|
||
|
* @vq: the struct virtqueue we're talking about
|
||
|
* @last_used_idx: virtqueue last used index
|
||
|
*
|
||
|
* Returns "true" if there are pending used buffers in the queue.
|
||
|
*/
|
||
|
bool virtqueue_poll(struct virtqueue *vq, u16 last_used_idx);
|
||
|
|
||
|
/**
|
||
|
* virtqueue_dump - dump the virtqueue for debugging
|
||
|
*
|
||
|
* @vq: the struct virtqueue we're talking about
|
||
|
*
|
||
|
* Caller must ensure we don't call this with other virtqueue operations
|
||
|
* at the same time (except where noted).
|
||
|
*/
|
||
|
void virtqueue_dump(struct virtqueue *vq);
|
||
|
|
||
|
/*
|
||
|
* Barriers in virtio are tricky. Since we are not in a hyperviosr/guest
|
||
|
* scenario, having these as nops is enough to work as expected.
|
||
|
*/
|
||
|
|
||
|
static inline void virtio_mb(void)
|
||
|
{
|
||
|
}
|
||
|
|
||
|
static inline void virtio_rmb(void)
|
||
|
{
|
||
|
}
|
||
|
|
||
|
static inline void virtio_wmb(void)
|
||
|
{
|
||
|
}
|
||
|
|
||
|
static inline void virtio_store_mb(__virtio16 *p, __virtio16 v)
|
||
|
{
|
||
|
WRITE_ONCE(*p, v);
|
||
|
}
|
||
|
|
||
|
#endif /* _LINUX_VIRTIO_RING_H */
|