diff options
Diffstat (limited to 'drivers/net/ethernet/chelsio/cxgb4/sge.c')
-rw-r--r-- | drivers/net/ethernet/chelsio/cxgb4/sge.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c b/drivers/net/ethernet/chelsio/cxgb4/sge.c index 01bd9c0dfe4e..196652a114c5 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/sge.c +++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c @@ -890,6 +890,114 @@ void cxgb4_write_sgl(const struct sk_buff *skb, struct sge_txq *q, } EXPORT_SYMBOL(cxgb4_write_sgl); +/* cxgb4_write_partial_sgl - populate SGL for partial packet + * @skb: the packet + * @q: the Tx queue we are writing into + * @sgl: starting location for writing the SGL + * @end: points right after the end of the SGL + * @addr: the list of bus addresses for the SGL elements + * @start: start offset in the SKB where partial data starts + * @len: length of data from @start to send out + * + * This API will handle sending out partial data of a skb if required. + * Unlike cxgb4_write_sgl, @start can be any offset into the skb data, + * and @len will decide how much data after @start offset to send out. + */ +void cxgb4_write_partial_sgl(const struct sk_buff *skb, struct sge_txq *q, + struct ulptx_sgl *sgl, u64 *end, + const dma_addr_t *addr, u32 start, u32 len) +{ + struct ulptx_sge_pair buf[MAX_SKB_FRAGS / 2 + 1] = {0}, *to; + u32 frag_size, skb_linear_data_len = skb_headlen(skb); + struct skb_shared_info *si = skb_shinfo(skb); + u8 i = 0, frag_idx = 0, nfrags = 0; + skb_frag_t *frag; + + /* Fill the first SGL either from linear data or from partial + * frag based on @start. + */ + if (unlikely(start < skb_linear_data_len)) { + frag_size = min(len, skb_linear_data_len - start); + sgl->len0 = htonl(frag_size); + sgl->addr0 = cpu_to_be64(addr[0] + start); + len -= frag_size; + nfrags++; + } else { + start -= skb_linear_data_len; + frag = &si->frags[frag_idx]; + frag_size = skb_frag_size(frag); + /* find the first frag */ + while (start >= frag_size) { + start -= frag_size; + frag_idx++; + frag = &si->frags[frag_idx]; + frag_size = skb_frag_size(frag); + } + + frag_size = min(len, skb_frag_size(frag) - start); + sgl->len0 = cpu_to_be32(frag_size); + sgl->addr0 = cpu_to_be64(addr[frag_idx + 1] + start); + len -= frag_size; + nfrags++; + frag_idx++; + } + + /* If the entire partial data fit in one SGL, then send it out + * now. + */ + if (!len) + goto done; + + /* Most of the complexity below deals with the possibility we hit the + * end of the queue in the middle of writing the SGL. For this case + * only we create the SGL in a temporary buffer and then copy it. + */ + to = (u8 *)end > (u8 *)q->stat ? buf : sgl->sge; + + /* If the skb couldn't fit in first SGL completely, fill the + * rest of the frags in subsequent SGLs. Note that each SGL + * pair can store 2 frags. + */ + while (len) { + frag_size = min(len, skb_frag_size(&si->frags[frag_idx])); + to->len[i & 1] = cpu_to_be32(frag_size); + to->addr[i & 1] = cpu_to_be64(addr[frag_idx + 1]); + if (i && (i & 1)) + to++; + nfrags++; + frag_idx++; + i++; + len -= frag_size; + } + + /* If we ended in an odd boundary, then set the second SGL's + * length in the pair to 0. + */ + if (i & 1) + to->len[1] = cpu_to_be32(0); + + /* Copy from temporary buffer to Tx ring, in case we hit the + * end of the queue in the middle of writing the SGL. + */ + if (unlikely((u8 *)end > (u8 *)q->stat)) { + u32 part0 = (u8 *)q->stat - (u8 *)sgl->sge, part1; + + if (likely(part0)) + memcpy(sgl->sge, buf, part0); + part1 = (u8 *)end - (u8 *)q->stat; + memcpy(q->desc, (u8 *)buf + part0, part1); + end = (void *)q->desc + part1; + } + + /* 0-pad to multiple of 16 */ + if ((uintptr_t)end & 8) + *end = 0; +done: + sgl->cmd_nsge = htonl(ULPTX_CMD_V(ULP_TX_SC_DSGL) | + ULPTX_NSGE_V(nfrags)); +} +EXPORT_SYMBOL(cxgb4_write_partial_sgl); + /* This function copies 64 byte coalesced work request to * memory mapped BAR2 space. For coalesced WR SGE fetches * data from the FIFO instead of from Host. |