From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
SYS-DMAC can use 40bit address transfer, and it supports Descriptor
Mode too. Current SYS-DMAC driver disables Descriptor Mode if it was
40bit address today. But it can use Descriptor Mode with 40bit if
transfer Source/Destination address are located in same 4GiB region
in the 40 bit address space.
This patch enables it if all condition was clear
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
---
v1 -> v2
- do high_dev_addr / high_mem_addr in out of sg loop
- reuse if (dev_addr >> 32 != (dev_addr + size - 1) >> 32)
drivers/dma/sh/rcar-dmac.c | 52 ++++++++++++++++++++++++++++------------------
1 file changed, 32 insertions(+), 20 deletions(-)
diff --git a/drivers/dma/sh/rcar-dmac.c b/drivers/dma/sh/rcar-dmac.c
index 48b22d5..a420921 100644
--- a/drivers/dma/sh/rcar-dmac.c
+++ b/drivers/dma/sh/rcar-dmac.c
@@ -344,13 +344,19 @@ static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)
rcar_dmac_chan_write(chan, RCAR_DMARS, chan->mid_rid);
if (desc->hwdescs.use) {
- struct rcar_dmac_xfer_chunk *chunk;
+ struct rcar_dmac_xfer_chunk *chunk =
+ list_first_entry(&desc->chunks,
+ struct rcar_dmac_xfer_chunk, node);
dev_dbg(chan->chan.device->dev,
"chan%u: queue desc %p: %u@%pad\n",
chan->index, desc, desc->nchunks, &desc->hwdescs.dma);
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+ rcar_dmac_chan_write(chan, RCAR_DMAFIXSAR,
+ chunk->src_addr >> 32);
+ rcar_dmac_chan_write(chan, RCAR_DMAFIXDAR,
+ chunk->dst_addr >> 32);
rcar_dmac_chan_write(chan, RCAR_DMAFIXDPBASE,
desc->hwdescs.dma >> 32);
#endif
@@ -368,8 +374,6 @@ static void rcar_dmac_chan_start_xfer(struct rcar_dmac_chan *chan)
* should. Initialize it manually with the destination address
* of the first chunk.
*/
- chunk = list_first_entry(&desc->chunks,
- struct rcar_dmac_xfer_chunk, node);
rcar_dmac_chan_write(chan, RCAR_DMADAR,
chunk->dst_addr & 0xffffffff);
@@ -855,8 +859,12 @@ static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
unsigned int nchunks = 0;
unsigned int max_chunk_size;
unsigned int full_size = 0;
- bool highmem = false;
+ bool cross_boundary = false;
unsigned int i;
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+ u32 high_dev_addr = 0;
+ u32 high_mem_addr = 0;
+#endif
desc = rcar_dmac_desc_get(chan);
if (!desc)
@@ -882,6 +890,16 @@ static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
full_size += len;
+#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
+ if (i == 0) {
+ high_dev_addr = dev_addr >> 32;
+ high_mem_addr = mem_addr >> 32;
+ }
+
+ if ((dev_addr >> 32 != high_dev_addr) ||
+ (mem_addr >> 32 != high_mem_addr))
+ cross_boundary = true;
+#endif
while (len) {
unsigned int size = min(len, max_chunk_size);
@@ -890,18 +908,14 @@ static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
* Prevent individual transfers from crossing 4GB
* boundaries.
*/
- if (dev_addr >> 32 != (dev_addr + size - 1) >> 32)
+ if (dev_addr >> 32 != (dev_addr + size - 1) >> 32) {
size = ALIGN(dev_addr, 1ULL << 32) - dev_addr;
- if (mem_addr >> 32 != (mem_addr + size - 1) >> 32)
+ cross_boundary = true;
+ }
+ if (mem_addr >> 32 != (mem_addr + size - 1) >> 32) {
size = ALIGN(mem_addr, 1ULL << 32) - mem_addr;
-
- /*
- * Check if either of the source or destination address
- * can't be expressed in 32 bits. If so we can't use
- * hardware descriptor lists.
- */
- if (dev_addr >> 32 || mem_addr >> 32)
- highmem = true;
+ cross_boundary = true;
+ }
#endif
chunk = rcar_dmac_xfer_chunk_get(chan);
@@ -943,13 +957,11 @@ static void rcar_dmac_chan_configure_desc(struct rcar_dmac_chan *chan,
* Use hardware descriptor lists if possible when more than one chunk
* needs to be transferred (otherwise they don't make much sense).
*
- * The highmem check currently covers the whole transfer. As an
- * optimization we could use descriptor lists for consecutive lowmem
- * chunks and direct manual mode for highmem chunks. Whether the
- * performance improvement would be significant enough compared to the
- * additional complexity remains to be investigated.
+ * Source/Destination address should be located in same 4GiB region
+ * in the 40bit address space when it uses Hardware descriptor,
+ * and cross_boundary is checking it.
*/
- desc->hwdescs.use = !highmem && nchunks > 1;
+ desc->hwdescs.use = !cross_boundary && nchunks > 1;
if (desc->hwdescs.use) {
if (rcar_dmac_fill_hwdesc(chan, desc) < 0)
desc->hwdescs.use = false;
--
1.9.1
--
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