}
}
+#ifdef EFX_USE_PIO
+
+struct efx_short_copy_buffer {
+ int used;
+ u8 buf[L1_CACHE_BYTES];
+};
+
+/* Copy to PIO, respecting that writes to PIO buffers must be dword aligned.
+ * Advances piobuf pointer. Leaves additional data in the copy buffer.
+ */
+static void efx_memcpy_toio_aligned(struct efx_nic *efx, u8 __iomem **piobuf,
+ u8 *data, int len,
+ struct efx_short_copy_buffer *copy_buf)
+{
+ int block_len = len & ~(sizeof(copy_buf->buf) - 1);
+
+ memcpy_toio(*piobuf, data, block_len);
+ *piobuf += block_len;
+ len -= block_len;
+
+ if (len) {
+ data += block_len;
+ BUG_ON(copy_buf->used);
+ BUG_ON(len > sizeof(copy_buf->buf));
+ memcpy(copy_buf->buf, data, len);
+ copy_buf->used = len;
+ }
+}
+
+/* Copy to PIO, respecting dword alignment, popping data from copy buffer first.
+ * Advances piobuf pointer. Leaves additional data in the copy buffer.
+ */
+static void efx_memcpy_toio_aligned_cb(struct efx_nic *efx, u8 __iomem **piobuf,
+ u8 *data, int len,
+ struct efx_short_copy_buffer *copy_buf)
+{
+ if (copy_buf->used) {
+ /* if the copy buffer is partially full, fill it up and write */
+ int copy_to_buf =
+ min_t(int, sizeof(copy_buf->buf) - copy_buf->used, len);
+
+ memcpy(copy_buf->buf + copy_buf->used, data, copy_to_buf);
+ copy_buf->used += copy_to_buf;
+
+ /* if we didn't fill it up then we're done for now */
+ if (copy_buf->used < sizeof(copy_buf->buf))
+ return;
+
+ memcpy_toio(*piobuf, copy_buf->buf, sizeof(copy_buf->buf));
+ *piobuf += sizeof(copy_buf->buf);
+ data += copy_to_buf;
+ len -= copy_to_buf;
+ copy_buf->used = 0;
+ }
+
+ efx_memcpy_toio_aligned(efx, piobuf, data, len, copy_buf);
+}
+
+static void efx_flush_copy_buffer(struct efx_nic *efx, u8 __iomem *piobuf,
+ struct efx_short_copy_buffer *copy_buf)
+{
+ /* if there's anything in it, write the whole buffer, including junk */
+ if (copy_buf->used)
+ memcpy_toio(piobuf, copy_buf->buf, sizeof(copy_buf->buf));
+}
+
+/* Traverse skb structure and copy fragments in to PIO buffer.
+ * Advances piobuf pointer.
+ */
+static void efx_skb_copy_bits_to_pio(struct efx_nic *efx, struct sk_buff *skb,
+ u8 __iomem **piobuf,
+ struct efx_short_copy_buffer *copy_buf)
+{
+ int i;
+
+ efx_memcpy_toio_aligned(efx, piobuf, skb->data, skb_headlen(skb),
+ copy_buf);
+
+ for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
+ skb_frag_t *f = &skb_shinfo(skb)->frags[i];
+ u8 *vaddr;
+
+ vaddr = kmap_atomic(skb_frag_page(f));
+
+ efx_memcpy_toio_aligned_cb(efx, piobuf, vaddr + f->page_offset,
+ skb_frag_size(f), copy_buf);
+ kunmap_atomic(vaddr);
+ }
+
+ EFX_BUG_ON_PARANOID(skb_shinfo(skb)->frag_list);
+}
+
+static struct efx_tx_buffer *
+efx_enqueue_skb_pio(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
+{
+ struct efx_tx_buffer *buffer =
+ efx_tx_queue_get_insert_buffer(tx_queue);
+ u8 __iomem *piobuf = tx_queue->piobuf;
+
+ /* Copy to PIO buffer. Ensure the writes are padded to the end
+ * of a cache line, as this is required for write-combining to be
+ * effective on at least x86.
+ */
+
+ if (skb_shinfo(skb)->nr_frags) {
+ /* The size of the copy buffer will ensure all writes
+ * are the size of a cache line.
+ */
+ struct efx_short_copy_buffer copy_buf;
+
+ copy_buf.used = 0;
+
+ efx_skb_copy_bits_to_pio(tx_queue->efx, skb,
+ &piobuf, ©_buf);
+ efx_flush_copy_buffer(tx_queue->efx, piobuf, ©_buf);
+ } else {
+ /* Pad the write to the size of a cache line.
+ * We can do this because we know the skb_shared_info sruct is
+ * after the source, and the destination buffer is big enough.
+ */
+ BUILD_BUG_ON(L1_CACHE_BYTES >
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+ memcpy_toio(tx_queue->piobuf, skb->data,
+ ALIGN(skb->len, L1_CACHE_BYTES));
+ }
+
+ EFX_POPULATE_QWORD_5(buffer->option,
+ ESF_DZ_TX_DESC_IS_OPT, 1,
+ ESF_DZ_TX_OPTION_TYPE, ESE_DZ_TX_OPTION_DESC_PIO,
+ ESF_DZ_TX_PIO_CONT, 0,
+ ESF_DZ_TX_PIO_BYTE_CNT, skb->len,
+ ESF_DZ_TX_PIO_BUF_ADDR,
+ tx_queue->piobuf_offset);
+ ++tx_queue->pio_packets;
+ ++tx_queue->insert_count;
+ return buffer;
+}
+#endif /* EFX_USE_PIO */
+
/*
* Add a socket buffer to a TX queue
*
return NETDEV_TX_OK;
}
+ /* Consider using PIO for short packets */
+#ifdef EFX_USE_PIO
+ if (skb->len <= efx_piobuf_size && tx_queue->piobuf &&
+ efx_nic_tx_is_empty(tx_queue) &&
+ efx_nic_tx_is_empty(efx_tx_queue_partner(tx_queue))) {
+ buffer = efx_enqueue_skb_pio(tx_queue, skb);
+ dma_flags = EFX_TX_BUF_OPTION;
+ goto finish_packet;
+ }
+#endif
+
/* Map for DMA. Use dma_map_single rather than dma_map_page
* since this is more efficient on machines with sparse
* memory.
}
/* Transfer ownership of the skb to the final buffer */
+finish_packet:
buffer->skb = skb;
buffer->flags = EFX_TX_BUF_SKB | dma_flags;
projects / karo-tx-linux.git / blobdiff