/*
* Try to receive a packet.
*/
static ssize_t
e1000_recv(struct netdriver_data * data, size_t max)
{
e1000_t *e;
e1000_rx_desc_t *desc;
unsigned int head, tail, cur;
char *ptr;
size_t size;
e = &e1000_state;
/* If the queue head and tail are equal, the queue is empty. */
head = e1000_reg_read(e, E1000_REG_RDH);
tail = e1000_reg_read(e, E1000_REG_RDT);
E1000_DEBUG(4, ("%s: head=%u, tail=%u\n", e->name, head, tail));
if (head == tail)
return SUSPEND;
/* Has a packet been received? */
cur = (tail + 1) % e->rx_desc_count;
desc = &e->rx_desc[cur];
if (!(desc->status & E1000_RX_STATUS_DONE))
return SUSPEND;
/*
* HACK: we expect all packets to fit in a single receive buffer.
* Eventually, some sort of support to deal with packets spanning
* multiple receive descriptors should be added. For now, we panic,
* so that we can continue after the restart; this is already an
* improvement over freezing (the old behavior of this driver).
*/
size = desc->length;
if (!(desc->status & E1000_RX_STATUS_EOP))
panic("received packet too large");
/* Copy the packet to the caller. */
ptr = e->rx_buffer + cur * E1000_IOBUF_SIZE;
if (size > max)
size = max;
netdriver_copyout(data, 0, ptr, size);
/* Reset the descriptor. */
desc->status = 0;
/* Increment tail. */
e1000_reg_write(e, E1000_REG_RDT, cur);
/* Return the size of the received packet. */
return size;
}
/*
* Put a packet receive from the RX queue into a user buffer, and return the
* packet length. If there are no received packets, return SUSPEND.
*/
static ssize_t
virtio_net_recv(struct netdriver_data * data, size_t max)
{
struct packet *p;
ssize_t len;
/* Get the first received packet, if any. */
if (STAILQ_EMPTY(&recv_list))
return SUSPEND;
p = STAILQ_FIRST(&recv_list);
STAILQ_REMOVE_HEAD(&recv_list, next);
/* Copy out the packet contents. */
len = p->len - sizeof(struct virtio_net_hdr);
if (len > max)
len = max;
/*
* HACK: due to lack of padding, received packets may in fact be
* smaller than the minimum ethernet packet size. Inet will accept the
* packets just fine if we increase the length to its minimum. We
* already zeroed out the rest of the packet data, so this is safe.
*/
if (len < ETH_MIN_PACK_SIZE)
len = ETH_MIN_PACK_SIZE;
netdriver_copyout(data, 0, p->vdata, len);
/* Clean the packet. */
memset(p->vhdr, 0, sizeof(*p->vhdr));
memset(p->vdata, 0, MAX_PACK_SIZE);
STAILQ_INSERT_HEAD(&free_list, p, next);
/* Readd packets to the receive queue as necessary. */
virtio_net_refill_rx_queue();
return len;
}
/*============================================================================*
* lan8710a_recv *
*============================================================================*/
static ssize_t
lan8710a_recv(struct netdriver_data * data, size_t max)
{
lan8710a_t *e = &lan8710a_state;
lan8710a_desc_t *p_rx_desc;
u32_t flags;
u8_t *buf;
size_t off, size, chunk;
/*
* Only handle one packet at a time.
*/
p_rx_desc = &(e->rx_desc[e->rx_desc_idx]);
/* find next OWN descriptor with SOP flag */
while ((0 == (LAN8710A_DESC_FLAG_SOP & p_rx_desc->pkt_len_flags)) &&
(0 == (LAN8710A_DESC_FLAG_OWN & p_rx_desc->pkt_len_flags))) {
p_rx_desc->buffer_length_off = LAN8710A_IOBUF_SIZE;
/* set ownership of current descriptor to EMAC */
p_rx_desc->pkt_len_flags = LAN8710A_DESC_FLAG_OWN;
e->rx_desc_idx++;
if (LAN8710A_NUM_RX_DESC == e->rx_desc_idx)
e->rx_desc_idx = 0;
p_rx_desc = &(e->rx_desc[e->rx_desc_idx]);
}
if (0 == (LAN8710A_DESC_FLAG_SOP & p_rx_desc->pkt_len_flags)) {
/* SOP was not found */
return SUSPEND;
}
/*
* Copy data from descriptors, from SOP to EOP inclusive.
* TODO: make sure that the presence of a SOP slot implies the presence
* of an EOP slot, because we are not checking for ownership below..
*/
size = 0;
off = 0;
for (;;) {
buf = e->p_rx_buf + e->rx_desc_idx * LAN8710A_IOBUF_SIZE + off;
chunk = p_rx_desc->buffer_length_off & 0xFFFF;
/* Truncate packets that are too large. */
if (chunk > max - size)
chunk = max - size;
if (chunk > 0) {
netdriver_copyout(data, size, buf, chunk);
size += chunk;
}
flags = p_rx_desc->pkt_len_flags;
/* Whole buffer move to the next descriptor */
p_rx_desc->buffer_length_off = LAN8710A_IOBUF_SIZE;
/* set ownership of current desc to EMAC */
p_rx_desc->pkt_len_flags = LAN8710A_DESC_FLAG_OWN;
e->rx_desc_idx++;
if (LAN8710A_NUM_RX_DESC == e->rx_desc_idx)
e->rx_desc_idx = 0;
p_rx_desc = &(e->rx_desc[e->rx_desc_idx]);
/* if EOP flag is set -> stop processing */
if (flags & LAN8710A_DESC_FLAG_EOP)
break;
/*
* TODO: the upper 16 bits of buffer_length_off are used *only*
* for descriptors *after* the first one; I'm retaining this
* behavior because I don't have the chip's spec, but it may be
* better to simplify/correct this behavior. --David
*/
off = p_rx_desc->buffer_length_off >> 16;
}
return size;
}
