This should provide support to unmap scatterlist with the
dmaengine_unmap_data. We will support only 1 scatterlist per
direction. The DMA addresses array has been overloaded for the
2 or less entries DMA unmap data structure in order to store the
SG pointer(s).
Signed-off-by: Dave Jiang <dave.ji...@intel.com>
---
drivers/dma/dmaengine.c | 45 ++++++++++++++++++++++++++++++++++++---------
include/linux/dmaengine.h | 4 ++++
2 files changed, 40 insertions(+), 9 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index d9118ec..81d10c97 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1126,16 +1126,35 @@ static void dmaengine_unmap(struct kref *kref)
{
struct dmaengine_unmap_data *unmap = container_of(kref, typeof(*unmap),
kref);
struct device *dev = unmap->dev;
- int cnt, i;
+ int cnt, i, sg_nents;
+ struct scatterlist *sg;
+
+ sg_nents = dma_unmap_data_sg_to_nents(unmap, unmap->map_cnt);
+ if (sg_nents) {
+ i = 0;
+ cnt = 1;
+ sg = (struct scatterlist *)unmap->addr[i];
+ dma_unmap_sg(dev, sg, sg_nents, DMA_TO_DEVICE);
+ } else {
+ cnt = unmap->to_cnt;
+ for (i = 0; i < cnt; i++)
+ dma_unmap_page(dev, unmap->addr[i], unmap->len,
+ DMA_TO_DEVICE);
+ }
+
+ sg_nents = dma_unmap_data_sg_from_nents(unmap, unmap->map_cnt);
+ if (sg_nents) {
+ sg = (struct scatterlist *)unmap->addr[i];
+ dma_unmap_sg(dev, sg, sg_nents, DMA_FROM_DEVICE);
+ cnt++;
+ i++;
+ } else {
+ cnt += unmap->from_cnt;
+ for (; i < cnt; i++)
+ dma_unmap_page(dev, unmap->addr[i], unmap->len,
+ DMA_FROM_DEVICE);
+ }
- cnt = unmap->to_cnt;
- for (i = 0; i < cnt; i++)
- dma_unmap_page(dev, unmap->addr[i], unmap->len,
- DMA_TO_DEVICE);
- cnt += unmap->from_cnt;
- for (; i < cnt; i++)
- dma_unmap_page(dev, unmap->addr[i], unmap->len,
- DMA_FROM_DEVICE);
cnt += unmap->bidi_cnt;
for (; i < cnt; i++) {
if (unmap->addr[i] == 0)
@@ -1179,6 +1198,10 @@ static int __init dmaengine_init_unmap_pool(void)
size = sizeof(struct dmaengine_unmap_data) +
sizeof(dma_addr_t) * p->size;
+ /* add 2 more entries for SG nents overload */
+ if (i == 0)
+ size += sizeof(dma_addr_t) * 2;
+
p->cache = kmem_cache_create(p->name, size, 0,
SLAB_HWCACHE_ALIGN, NULL);
if (!p->cache)
@@ -1205,6 +1228,10 @@ dmaengine_get_unmap_data(struct device *dev, int nr,
gfp_t flags)
return NULL;
memset(unmap, 0, sizeof(*unmap));
+ /* clear the overloaded sg nents entries */
+ if (nr < 3)
+ memset(&unmap->addr[nr], 0,
+ DMA_UNMAP_SG_ENTS * sizeof(dma_addr_t));
kref_init(&unmap->kref);
unmap->dev = dev;
unmap->map_cnt = nr;
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 060f152..ba978dd 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -475,6 +475,10 @@ struct dmaengine_unmap_data {
dma_addr_t addr[0];
};
+#define DMA_UNMAP_SG_ENTS 2
+#define dma_unmap_data_sg_to_nents(x, n) x->addr[n]
+#define dma_unmap_data_sg_from_nents(x, n) x->addr[n+1]
+
/**
* struct dma_async_tx_descriptor - async transaction descriptor
* ---dma generic offload fields---
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