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.jiang@xxxxxxxxx>
---
drivers/dma/dmaengine.c | 45 ++++++++++++++++++++++++++++++++++++---------
include/linux/dmaengine.h | 22 ++++++++++++++++++++++
2 files changed, 58 insertions(+), 9 deletions(-)
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
index d9a71f0..7d1f7ad 100644
--- a/drivers/dma/dmaengine.c
+++ b/drivers/dma/dmaengine.c
@@ -1130,16 +1130,35 @@ 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;
+ dma_unmap_data_get_virt(unmap, sg, 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) {
+ dma_unmap_data_get_virt(unmap, sg, 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)
@@ -1183,6 +1202,10 @@ 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)
@@ -1209,6 +1232,10 @@ 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 fc25475..3a7fc68 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -476,6 +476,28 @@ 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]
+
+#if !defined(CONFIG_64BIT) && defined(CONFIG_PCI_BUS_ADDR_T_64BIT)
+/* 32bit CPU, 64bit DMA */
+#define dma_unmap_data_set_virt(u, virt, idx) \
+ do {\
+ u32 tmp = (u32)virt; \
+ u->addr[idx] = tmp; \
+ } while (0);
+
+#define dma_unmap_data_get_virt(u, ptr, idx) \
+ do {\
+ u32 tmp = u->addr[idx]; \
+ ptr = (void *)tmp; \
+ } while (0);
+#else
+#define dma_unmap_data_set_virt(u, virt, idx) u->addr[idx] = (dma_addr_t)virt;
+#define dma_unmap_data_get_virt(u, ptr, idx) ptr = (void *)u->addr[idx]
+#endif
+
/**
* struct dma_async_tx_descriptor - async transaction descriptor
* ---dma generic offload fields---
--
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