static int unipro_continue_xfer(struct unipro_xfer_descriptor *desc)
{
size_t xfer_len;
desc->remaining_xfer_len -= desc->dma_arg.unipro_tx_arg.next_transfer_len;
xfer_len = unipro_get_tx_free_buffer_space(desc->cport);
if (!xfer_len)
return -ENOSPC;
xfer_len = MIN(desc->remaining_xfer_len, xfer_len);
desc->dma_arg.unipro_tx_arg.next_transfer_len = xfer_len;
if (xfer_len == desc->remaining_xfer_len)
desc->dma_arg.unipro_tx_arg.eom_addr = CPORT_EOM_BIT(desc->cport);
return 0;
}
static int unipro_dma_xfer(struct unipro_xfer_descriptor *desc,
struct dma_channel *channel)
{
int retval;
size_t xfer_len;
void *cport_buf;
void *xfer_buf;
xfer_len = unipro_get_tx_free_buffer_space(desc->cport);
if (!xfer_len)
return -ENOSPC;
xfer_len = MIN(desc->remaining_xfer_len, xfer_len);
desc->channel = channel;
desc->dma_arg.unipro_tx_arg.next_transfer_len = xfer_len;
if (xfer_len == desc->remaining_xfer_len)
desc->dma_arg.unipro_tx_arg.eom_addr = CPORT_EOM_BIT(desc->cport);
DBG_UNIPRO("xfer: chan=%u, len=%zu\n", channel->id, xfer_len);
cport_buf = desc->cport->tx_buf;
xfer_buf = (void*) desc->data;
/* resuming a paused xfer */
if (desc->remaining_xfer_len != desc->len) {
cport_buf = (char*) cport_buf + 1; /* skip the start byte */
/* move buffer offset to the beginning of the remaning bytes to xfer */
xfer_buf = (char*) xfer_buf + (desc->len - desc->remaining_xfer_len);
}
retval = device_dma_transfer(unipro_dma.dev, channel->id, xfer_buf,
cport_buf, xfer_len, &desc->dma_arg);
if (retval) {
lowsyslog("unipro: failed to start DMA transfer: %d\n", retval);
return retval;
}
return 0;
}
/**
* @brief Set EOM (End Of Message) flag
* @param[in] cport: CPort handle
*/
static inline void unipro_set_eom_flag(struct cport *cport)
{
putreg8(1, CPORT_EOM_BIT(cport));
}
