The current descriptor layout is:
struct dw_edma_desc *desc
└─ chunk list
└─ burst list
Creating a DMA descriptor requires at least three kzalloc() calls because
each burst is allocated as a linked-list node. Since the number of bursts
is already known when the descriptor is created, a linked list is not
necessary.
Allocate a burst array when creating each chunk to simplify the code and
eliminate one kzalloc() call.
Signed-off-by: Frank Li <[email protected]>
---
drivers/dma/dw-edma/dw-edma-core.c | 114 +++++++------------------------------
drivers/dma/dw-edma/dw-edma-core.h | 9 +--
2 files changed, 24 insertions(+), 99 deletions(-)
diff --git a/drivers/dma/dw-edma/dw-edma-core.c
b/drivers/dma/dw-edma/dw-edma-core.c
index
37918f733eb4d36c7ced6418b85a885affadc8f7..9e65155fd93d69ddbc8235fad671fad4dc120979
100644
--- a/drivers/dma/dw-edma/dw-edma-core.c
+++ b/drivers/dma/dw-edma/dw-edma-core.c
@@ -40,38 +40,15 @@ u64 dw_edma_get_pci_address(struct dw_edma_chan *chan,
phys_addr_t cpu_addr)
return cpu_addr;
}
-static struct dw_edma_burst *dw_edma_alloc_burst(struct dw_edma_chunk *chunk)
-{
- struct dw_edma_burst *burst;
-
- burst = kzalloc(sizeof(*burst), GFP_NOWAIT);
- if (unlikely(!burst))
- return NULL;
-
- INIT_LIST_HEAD(&burst->list);
- if (chunk->burst) {
- /* Create and add new element into the linked list */
- chunk->bursts_alloc++;
- list_add_tail(&burst->list, &chunk->burst->list);
- } else {
- /* List head */
- chunk->bursts_alloc = 0;
- chunk->burst = burst;
- }
-
- return burst;
-}
-
-static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc)
+static struct dw_edma_chunk *dw_edma_alloc_chunk(struct dw_edma_desc *desc,
u32 nburst)
{
struct dw_edma_chan *chan = desc->chan;
struct dw_edma_chunk *chunk;
- chunk = kzalloc(sizeof(*chunk), GFP_NOWAIT);
+ chunk = kzalloc(struct_size(chunk, burst, nburst), GFP_NOWAIT);
if (unlikely(!chunk))
return NULL;
- INIT_LIST_HEAD(&chunk->list);
chunk->chan = chan;
/* Toggling change bit (CB) in each chunk, this is a mechanism to
* inform the eDMA HW block that this is a new linked list ready
@@ -81,20 +58,10 @@ static struct dw_edma_chunk *dw_edma_alloc_chunk(struct
dw_edma_desc *desc)
*/
chunk->cb = !(desc->chunks_alloc % 2);
- if (desc->chunk) {
- /* Create and add new element into the linked list */
- if (!dw_edma_alloc_burst(chunk)) {
- kfree(chunk);
- return NULL;
- }
- desc->chunks_alloc++;
- list_add_tail(&chunk->list, &desc->chunk->list);
- } else {
- /* List head */
- chunk->burst = NULL;
- desc->chunks_alloc = 0;
- desc->chunk = chunk;
- }
+ chunk->nburst = nburst;
+
+ list_add_tail(&chunk->list, &desc->chunk_list);
+ desc->chunks_alloc++;
return chunk;
}
@@ -108,53 +75,23 @@ static struct dw_edma_desc *dw_edma_alloc_desc(struct
dw_edma_chan *chan)
return NULL;
desc->chan = chan;
- if (!dw_edma_alloc_chunk(desc)) {
- kfree(desc);
- return NULL;
- }
- return desc;
-}
+ INIT_LIST_HEAD(&desc->chunk_list);
-static void dw_edma_free_burst(struct dw_edma_chunk *chunk)
-{
- struct dw_edma_burst *child, *_next;
-
- /* Remove all the list elements */
- list_for_each_entry_safe(child, _next, &chunk->burst->list, list) {
- list_del(&child->list);
- kfree(child);
- chunk->bursts_alloc--;
- }
-
- /* Remove the list head */
- kfree(child);
- chunk->burst = NULL;
+ return desc;
}
-static void dw_edma_free_chunk(struct dw_edma_desc *desc)
+static void dw_edma_free_desc(struct dw_edma_desc *desc)
{
struct dw_edma_chunk *child, *_next;
- if (!desc->chunk)
- return;
-
/* Remove all the list elements */
- list_for_each_entry_safe(child, _next, &desc->chunk->list, list) {
- dw_edma_free_burst(child);
+ list_for_each_entry_safe(child, _next, &desc->chunk_list, list) {
list_del(&child->list);
kfree(child);
desc->chunks_alloc--;
}
- /* Remove the list head */
- kfree(child);
- desc->chunk = NULL;
-}
-
-static void dw_edma_free_desc(struct dw_edma_desc *desc)
-{
- dw_edma_free_chunk(desc);
kfree(desc);
}
@@ -166,15 +103,11 @@ static void vchan_free_desc(struct virt_dma_desc *vdesc)
static void dw_edma_core_start(struct dw_edma_chunk *chunk, bool first)
{
struct dw_edma_chan *chan = chunk->chan;
- struct dw_edma_burst *child;
u32 i = 0;
- int j;
- j = chunk->bursts_alloc;
- list_for_each_entry(child, &chunk->burst->list, list) {
- j--;
- dw_edma_core_ll_data(chan, child, i++, chunk->cb, !j);
- }
+ for (i = 0; i < chunk->nburst; i++)
+ dw_edma_core_ll_data(chan, &chunk->burst[i], i, chunk->cb,
+ i == chunk->nburst - 1);
dw_edma_core_ll_link(chan, i, chunk->cb, chan->ll_region.paddr);
@@ -198,14 +131,13 @@ static int dw_edma_start_transfer(struct dw_edma_chan
*chan)
if (!desc)
return 0;
- child = list_first_entry_or_null(&desc->chunk->list,
+ child = list_first_entry_or_null(&desc->chunk_list,
struct dw_edma_chunk, list);
if (!child)
return 0;
dw_edma_core_start(child, !desc->xfer_sz);
desc->xfer_sz += child->xfer_sz;
- dw_edma_free_burst(child);
list_del(&child->list);
kfree(child);
desc->chunks_alloc--;
@@ -375,13 +307,13 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer,
struct dw_edma_chan *chan = dchan2dw_edma_chan(xfer->dchan);
enum dma_transfer_direction dir = xfer->direction;
struct scatterlist *sg = NULL;
- struct dw_edma_chunk *chunk;
+ struct dw_edma_chunk *chunk = NULL;
struct dw_edma_burst *burst;
struct dw_edma_desc *desc;
u64 src_addr, dst_addr;
size_t fsz = 0;
u32 cnt = 0;
- int i;
+ u32 i;
if (!chan->configured)
return NULL;
@@ -441,10 +373,6 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer,
if (unlikely(!desc))
goto err_alloc;
- chunk = dw_edma_alloc_chunk(desc);
- if (unlikely(!chunk))
- goto err_alloc;
-
if (xfer->type == EDMA_XFER_INTERLEAVED) {
src_addr = xfer->xfer.il->src_start;
dst_addr = xfer->xfer.il->dst_start;
@@ -472,15 +400,15 @@ dw_edma_device_transfer(struct dw_edma_transfer *xfer,
if (xfer->type == EDMA_XFER_SCATTER_GATHER && !sg)
break;
- if (chunk->bursts_alloc == chan->ll_max) {
- chunk = dw_edma_alloc_chunk(desc);
+ if (!(i % chan->ll_max)) {
+ u32 n = min(cnt - i, chan->ll_max);
+
+ chunk = dw_edma_alloc_chunk(desc, n);
if (unlikely(!chunk))
goto err_alloc;
}
- burst = dw_edma_alloc_burst(chunk);
- if (unlikely(!burst))
- goto err_alloc;
+ burst = chunk->burst + (i % chan->ll_max);
if (xfer->type == EDMA_XFER_CYCLIC)
burst->sz = xfer->xfer.cyclic.len;
diff --git a/drivers/dma/dw-edma/dw-edma-core.h
b/drivers/dma/dw-edma/dw-edma-core.h
index
7a0d8405eb7feaedf4b19fd83bbeb5d24781bb7b..1930c3bce2bf33fdfbf4e8d99002483a4565faed
100644
--- a/drivers/dma/dw-edma/dw-edma-core.h
+++ b/drivers/dma/dw-edma/dw-edma-core.h
@@ -43,7 +43,6 @@ struct dw_edma_chan;
struct dw_edma_chunk;
struct dw_edma_burst {
- struct list_head list;
u64 sar;
u64 dar;
u32 sz;
@@ -52,18 +51,16 @@ struct dw_edma_burst {
struct dw_edma_chunk {
struct list_head list;
struct dw_edma_chan *chan;
- struct dw_edma_burst *burst;
-
- u32 bursts_alloc;
-
u8 cb;
u32 xfer_sz;
+ u32 nburst;
+ struct dw_edma_burst burst[] __counted_by(nburst);
};
struct dw_edma_desc {
struct virt_dma_desc vd;
struct dw_edma_chan *chan;
- struct dw_edma_chunk *chunk;
+ struct list_head chunk_list;
u32 chunks_alloc;
--
2.34.1
