From 22843545b20007ae33bc3774043303e0b44e3d65 Mon Sep 17 00:00:00 2001 From: Lior Amsalem Date: Wed, 27 Aug 2014 10:52:55 -0300 Subject: [PATCH] dma: mv_xor: Add support for DMA_INTERRUPT The driver is capable of supporting DMA_INTERRUPT by issuing a dummy 128-byte transfer. This helps removing a poll in the async_tx stack, replacing it with a completion interrupt. Signed-off-by: Lior Amsalem Signed-off-by: Ezequiel Garcia Signed-off-by: Vinod Koul --- drivers/dma/mv_xor.c | 34 ++++++++++++++++++++++++++++++++++ drivers/dma/mv_xor.h | 11 ++++++----- 2 files changed, 40 insertions(+), 5 deletions(-) diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c index 744a0077e5aa..769d35c3a82b 100644 --- a/drivers/dma/mv_xor.c +++ b/drivers/dma/mv_xor.c @@ -538,6 +538,24 @@ mv_xor_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src, return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags); } +static struct dma_async_tx_descriptor * +mv_xor_prep_dma_interrupt(struct dma_chan *chan, unsigned long flags) +{ + struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan); + dma_addr_t src, dest; + size_t len; + + src = mv_chan->dummy_src_addr; + dest = mv_chan->dummy_dst_addr; + len = MV_XOR_MIN_BYTE_COUNT; + + /* + * We implement the DMA_INTERRUPT operation as a minimum sized + * XOR operation with a single dummy source address. + */ + return mv_xor_prep_dma_xor(chan, dest, &src, 1, len, flags); +} + static void mv_xor_free_chan_resources(struct dma_chan *chan) { struct mv_xor_chan *mv_chan = to_mv_xor_chan(chan); @@ -881,6 +899,10 @@ static int mv_xor_channel_remove(struct mv_xor_chan *mv_chan) dma_free_coherent(dev, MV_XOR_POOL_SIZE, mv_chan->dma_desc_pool_virt, mv_chan->dma_desc_pool); + dma_unmap_single(dev, mv_chan->dummy_src_addr, + MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE); + dma_unmap_single(dev, mv_chan->dummy_dst_addr, + MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE); list_for_each_entry_safe(chan, _chan, &mv_chan->dmadev.channels, device_node) { @@ -910,6 +932,16 @@ mv_xor_channel_add(struct mv_xor_device *xordev, dma_dev = &mv_chan->dmadev; + /* + * These source and destination dummy buffers are used to implement + * a DMA_INTERRUPT operation as a minimum-sized XOR operation. + * Hence, we only need to map the buffers at initialization-time. + */ + mv_chan->dummy_src_addr = dma_map_single(dma_dev->dev, + mv_chan->dummy_src, MV_XOR_MIN_BYTE_COUNT, DMA_FROM_DEVICE); + mv_chan->dummy_dst_addr = dma_map_single(dma_dev->dev, + mv_chan->dummy_dst, MV_XOR_MIN_BYTE_COUNT, DMA_TO_DEVICE); + /* allocate coherent memory for hardware descriptors * note: writecombine gives slightly better performance, but * requires that we explicitly flush the writes @@ -934,6 +966,8 @@ mv_xor_channel_add(struct mv_xor_device *xordev, dma_dev->dev = &pdev->dev; /* set prep routines based on capability */ + if (dma_has_cap(DMA_INTERRUPT, dma_dev->cap_mask)) + dma_dev->device_prep_dma_interrupt = mv_xor_prep_dma_interrupt; if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) dma_dev->device_prep_dma_memcpy = mv_xor_prep_dma_memcpy; if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) { diff --git a/drivers/dma/mv_xor.h b/drivers/dma/mv_xor.h index de400365bc49..78edc7e44569 100644 --- a/drivers/dma/mv_xor.h +++ b/drivers/dma/mv_xor.h @@ -28,6 +28,9 @@ #define MV_XOR_THRESHOLD 1 #define MV_XOR_MAX_CHANNELS 2 +#define MV_XOR_MIN_BYTE_COUNT SZ_128 +#define MV_XOR_MAX_BYTE_COUNT (SZ_16M - 1) + /* Values for the XOR_CONFIG register */ #define XOR_OPERATION_MODE_XOR 0 #define XOR_OPERATION_MODE_MEMCPY 2 @@ -116,6 +119,9 @@ struct mv_xor_chan { struct list_head all_slots; int slots_allocated; struct tasklet_struct irq_tasklet; + char dummy_src[MV_XOR_MIN_BYTE_COUNT]; + char dummy_dst[MV_XOR_MIN_BYTE_COUNT]; + dma_addr_t dummy_src_addr, dummy_dst_addr; }; /** @@ -184,9 +190,4 @@ struct mv_xor_desc { #define mv_hw_desc_slot_idx(hw_desc, idx) \ ((void *)(((unsigned long)hw_desc) + ((idx) << 5))) -#define MV_XOR_MIN_BYTE_COUNT (128) -#define XOR_MAX_BYTE_COUNT ((16 * 1024 * 1024) - 1) -#define MV_XOR_MAX_BYTE_COUNT XOR_MAX_BYTE_COUNT - - #endif -- 2.20.1