The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other
computations. But the bandwidth of the entire DMA engine is shared
among all channels. This patch re-configures operations availability
such that one can achieve maximum performance for XOR and PQ
computation by removing the memory offload operations.
Signed-off-by: Rameshwar Prasad Sahu <rsahu@xxxxxxx>
---
drivers/dma/xgene-dma.c | 59 +------------------------------------------------
1 file changed, 1 insertion(+), 58 deletions(-)
diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c
index 8d57b1b..b291733 100644
--- a/drivers/dma/xgene-dma.c
+++ b/drivers/dma/xgene-dma.c
@@ -894,60 +894,6 @@ static void xgene_dma_free_chan_resources(struct dma_chan *dchan)
chan->desc_pool = NULL;
}
-static struct dma_async_tx_descriptor *xgene_dma_prep_memcpy(
- struct dma_chan *dchan, dma_addr_t dst, dma_addr_t src,
- size_t len, unsigned long flags)
-{
- struct xgene_dma_desc_sw *first = NULL, *new;
- struct xgene_dma_chan *chan;
- size_t copy;
-
- if (unlikely(!dchan || !len))
- return NULL;
-
- chan = to_dma_chan(dchan);
-
- do {
- /* Allocate the link descriptor from DMA pool */
- new = xgene_dma_alloc_descriptor(chan);
- if (!new)
- goto fail;
-
- /* Create the largest transaction possible */
- copy = min_t(size_t, len, XGENE_DMA_MAX_64B_DESC_BYTE_CNT);
-
- /* Prepare DMA descriptor */
- xgene_dma_prep_cpy_desc(chan, new, dst, src, copy);
-
- if (!first)
- first = new;
-
- new->tx.cookie = 0;
- async_tx_ack(&new->tx);
-
- /* Update metadata */
- len -= copy;
- dst += copy;
- src += copy;
-
- /* Insert the link descriptor to the LD ring */
- list_add_tail(&new->node, &first->tx_list);
- } while (len);
-
- new->tx.flags = flags; /* client is in control of this ack */
- new->tx.cookie = -EBUSY;
- list_splice(&first->tx_list, &new->tx_list);
-
- return &new->tx;
-
-fail:
- if (!first)
- return NULL;
-
- xgene_dma_free_desc_list(chan, &first->tx_list);
- return NULL;
-}
-
static struct dma_async_tx_descriptor *xgene_dma_prep_sg(
struct dma_chan *dchan, struct scatterlist *dst_sg,
u32 dst_nents, struct scatterlist *src_sg,
@@ -1707,7 +1653,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
dma_cap_zero(dma_dev->cap_mask);
/* Set DMA device capability */
- dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask);
dma_cap_set(DMA_SG, dma_dev->cap_mask);
/* Basically here, the X-Gene SoC DMA engine channel 0 supports XOR
@@ -1734,7 +1679,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan,
dma_dev->device_free_chan_resources = xgene_dma_free_chan_resources;
dma_dev->device_issue_pending = xgene_dma_issue_pending;
dma_dev->device_tx_status = xgene_dma_tx_status;
- dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy;
dma_dev->device_prep_dma_sg = xgene_dma_prep_sg;
if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
@@ -1787,8 +1731,7 @@ static int xgene_dma_async_register(struct xgene_dma *pdma, int id)
/* DMA capability info */
dev_info(pdma->dev,
- "%s: CAPABILITY ( %s%s%s%s)\n", dma_chan_name(&chan->dma_chan),
- dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask) ? "MEMCPY " : "",
+ "%s: CAPABILITY ( %s%s%s)\n", dma_chan_name(&chan->dma_chan),
dma_has_cap(DMA_SG, dma_dev->cap_mask) ? "SGCPY " : "",
dma_has_cap(DMA_XOR, dma_dev->cap_mask) ? "XOR " : "",
dma_has_cap(DMA_PQ, dma_dev->cap_mask) ? "PQ " : "");
--
1.8.2.1
--
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