1 /*
2 * Copyright (c) 2025 Antmicro <www.antmicro.com>
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/logging/log.h>
8 #include <zephyr/sys/byteorder.h>
9 #include <zephyr/drivers/virtio.h>
10 #include <zephyr/drivers/virtio/virtqueue.h>
11 #include "virtio_common.h"
12
13 LOG_MODULE_REGISTER(virtio_common, CONFIG_VIRTIO_LOG_LEVEL);
14
virtio_isr(const struct device * dev,uint8_t isr_status,uint16_t virtqueue_count)15 void virtio_isr(const struct device *dev, uint8_t isr_status, uint16_t virtqueue_count)
16 {
17 if (isr_status & VIRTIO_QUEUE_INTERRUPT) {
18 for (int i = 0; i < virtqueue_count; i++) {
19 struct virtq *vq = virtio_get_virtqueue(dev, i);
20 uint16_t used_idx = sys_le16_to_cpu(vq->used->idx);
21
22 while (vq->last_used_idx != used_idx) {
23 uint16_t idx = vq->last_used_idx % vq->num;
24 uint16_t idx_le = sys_cpu_to_le16(idx);
25 uint16_t chain_head_le = vq->used->ring[idx_le].id;
26 uint16_t chain_head = sys_le16_to_cpu(chain_head_le);
27 uint32_t used_len = sys_le32_to_cpu(
28 vq->used->ring[idx_le].len
29 );
30
31 /*
32 * We are making a copy here, because chain will be
33 * returned before invoking the callback and may be
34 * overwritten by the time callback is called. This
35 * is to allow callback to immediately place the
36 * descriptors back in the avail_ring
37 */
38 struct virtq_receive_callback_entry cbe =
39 vq->recv_cbs[chain_head];
40
41 uint16_t next = chain_head;
42 bool last = false;
43
44 /*
45 * We are done processing the descriptor chain, and
46 * we can add used descriptors back to the free stack.
47 * The only thing left to do is calling the callback
48 * associated with the chain, but it was saved above on
49 * the stack, so other code is free to use the descriptors
50 */
51 while (!last) {
52 uint16_t curr = next;
53 uint16_t curr_le = sys_cpu_to_le16(curr);
54
55 next = vq->desc[curr_le].next;
56 last = !(vq->desc[curr_le].flags & VIRTQ_DESC_F_NEXT);
57 virtq_add_free_desc(vq, curr);
58 }
59
60 vq->last_used_idx++;
61
62 if (cbe.cb) {
63 cbe.cb(cbe.opaque, used_len);
64 }
65 }
66 }
67 }
68 if (isr_status & VIRTIO_DEVICE_CONFIGURATION_INTERRUPT) {
69 LOG_ERR("device configuration change interrupt is currently unsupported");
70 }
71 }
72