| /****************************************************************************** |
| * Copyright (c) 2016 IBM Corporation |
| * All rights reserved. |
| * This program and the accompanying materials |
| * are made available under the terms of the BSD License |
| * which accompanies this distribution, and is available at |
| * http://www.opensource.org/licenses/bsd-license.php |
| * |
| * Contributors: |
| * IBM Corporation - initial implementation |
| *****************************************************************************/ |
| |
| /* |
| * Virtio serial device definitions. |
| * See Virtio 1.0 - 5.3 Console Device, for details |
| */ |
| #include <stdio.h> |
| #include <string.h> |
| #include <cpu.h> |
| #include <helpers.h> |
| #include <byteorder.h> |
| #include "virtio.h" |
| #include "virtio-serial.h" |
| #include "virtio-internal.h" |
| |
| #define DRIVER_FEATURE_SUPPORT VIRTIO_F_VERSION_1 |
| #define RX_ELEM_SIZE 4 |
| #define RX_NUM_ELEMS 128 |
| |
| #define RX_Q 0 |
| #define TX_Q 1 |
| |
| static uint16_t last_rx_idx; /* Last index in RX "used" ring */ |
| |
| int virtio_serial_init(struct virtio_device *dev) |
| { |
| struct vqs *vq_rx, *vq_tx; |
| int status = VIRTIO_STAT_ACKNOWLEDGE; |
| int i; |
| |
| /* Reset device */ |
| virtio_reset_device(dev); |
| |
| /* Acknowledge device. */ |
| virtio_set_status(dev, status); |
| |
| /* Tell HV that we know how to drive the device. */ |
| status |= VIRTIO_STAT_DRIVER; |
| virtio_set_status(dev, status); |
| |
| if (dev->features & VIRTIO_F_VERSION_1) { |
| /* Negotiate features and sets FEATURES_OK if successful */ |
| if (virtio_negotiate_guest_features(dev, DRIVER_FEATURE_SUPPORT)) |
| goto dev_error; |
| |
| virtio_get_status(dev, &status); |
| } |
| |
| vq_rx = virtio_queue_init_vq(dev, RX_Q); |
| if (!vq_rx) |
| goto dev_error; |
| |
| /* Allocate memory for multiple receive buffers */ |
| vq_rx->buf_mem = SLOF_alloc_mem(RX_ELEM_SIZE * RX_NUM_ELEMS); |
| if (!vq_rx->buf_mem) { |
| printf("virtio-serial: Failed to allocate buffers!\n"); |
| goto dev_error; |
| } |
| |
| /* Prepare receive buffer queue */ |
| for (i = 0; i < RX_NUM_ELEMS; i++) { |
| uint64_t addr = (uint64_t)vq_rx->buf_mem + i * RX_ELEM_SIZE; |
| |
| /* Descriptor for data: */ |
| virtio_fill_desc(vq_rx, i, dev->features, addr, 1, VRING_DESC_F_WRITE, 0); |
| vq_rx->avail->ring[i] = virtio_cpu_to_modern16(dev, i); |
| } |
| vq_rx->avail->idx = virtio_cpu_to_modern16(dev, RX_NUM_ELEMS); |
| sync(); |
| |
| last_rx_idx = virtio_modern16_to_cpu(dev, vq_rx->used->idx); |
| |
| vq_tx = virtio_queue_init_vq(dev, TX_Q); |
| if (!vq_tx) |
| goto dev_error; |
| |
| |
| /* Tell HV that setup succeeded */ |
| status |= VIRTIO_STAT_DRIVER_OK; |
| virtio_set_status(dev, status); |
| |
| return 1; |
| dev_error: |
| printf("%s: failed\n", __func__); |
| status |= VIRTIO_STAT_FAILED; |
| virtio_set_status(dev, status); |
| return 0; |
| } |
| |
| void virtio_serial_shutdown(struct virtio_device *dev) |
| { |
| /* Quiesce device */ |
| virtio_set_status(dev, VIRTIO_STAT_FAILED); |
| |
| /* Stop queues */ |
| virtio_queue_term_vq(dev, &dev->vq[TX_Q], TX_Q); |
| virtio_queue_term_vq(dev, &dev->vq[RX_Q], RX_Q); |
| |
| /* Reset device */ |
| virtio_reset_device(dev); |
| } |
| |
| int virtio_serial_putchar(struct virtio_device *dev, char c) |
| { |
| int id, ret; |
| uint32_t time; |
| volatile uint16_t *current_used_idx; |
| uint16_t last_used_idx, avail_idx; |
| struct vqs *vq = &dev->vq[TX_Q]; |
| |
| if (!vq->desc) |
| return 0; |
| |
| avail_idx = virtio_modern16_to_cpu(dev, vq->avail->idx); |
| |
| last_used_idx = vq->used->idx; |
| current_used_idx = &vq->used->idx; |
| |
| /* Determine descriptor index */ |
| id = avail_idx % vq->size; |
| |
| /* Set up virtqueue descriptor for header */ |
| virtio_fill_desc(vq, id, dev->features, (uint64_t)&c, 1, 0, 0); |
| |
| vq->avail->ring[avail_idx % vq->size] = virtio_cpu_to_modern16 (dev, id); |
| mb(); |
| vq->avail->idx = virtio_cpu_to_modern16(dev, avail_idx + 1); |
| |
| /* Tell HV that the queue is ready */ |
| virtio_queue_notify(dev, TX_Q); |
| |
| /* Wait for host to consume the descriptor */ |
| ret = 1; |
| time = SLOF_GetTimer() + VIRTIO_TIMEOUT; |
| while (*current_used_idx == last_used_idx) { |
| // do something better |
| mb(); |
| if (time < SLOF_GetTimer()) { |
| printf("virtio_serial_putchar failed! \n"); |
| ret = 0; |
| break; |
| } |
| } |
| |
| virtio_free_desc(vq, id, dev->features); |
| |
| return ret; |
| } |
| |
| char virtio_serial_getchar(struct virtio_device *dev) |
| { |
| int id, idx; |
| char buf[RX_NUM_ELEMS] = {0}; |
| uint16_t avail_idx; |
| struct vqs *vq_rx = &dev->vq[RX_Q]; |
| |
| idx = virtio_modern16_to_cpu(dev, vq_rx->used->idx); |
| if (last_rx_idx == idx) { |
| /* Nothing received yet */ |
| return 0; |
| } |
| |
| id = (virtio_modern32_to_cpu(dev, vq_rx->used->ring[last_rx_idx % vq_rx->size].id) + 1) |
| % vq_rx->size; |
| |
| /* Copy data to destination buffer */ |
| memcpy(buf, virtio_desc_addr(dev, RX_Q, id - 1), RX_ELEM_SIZE); |
| |
| /* Move indices to next entries */ |
| last_rx_idx = last_rx_idx + 1; |
| |
| avail_idx = virtio_modern16_to_cpu(dev, vq_rx->avail->idx); |
| vq_rx->avail->ring[avail_idx % vq_rx->size] = virtio_cpu_to_modern16(dev, id - 1); |
| sync(); |
| vq_rx->avail->idx = virtio_cpu_to_modern16(dev, avail_idx + 1); |
| sync(); |
| |
| /* Tell HV that RX queue entry is ready */ |
| virtio_queue_notify(dev, RX_Q); |
| |
| return buf[0]; |
| } |
| |
| int virtio_serial_haschar(struct virtio_device *dev) |
| { |
| struct vqs *vq_rx = &dev->vq[RX_Q]; |
| |
| if (last_rx_idx == virtio_modern16_to_cpu(dev, vq_rx->used->idx)) |
| return 0; |
| else |
| return 1; |
| } |