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Commit 22843545 authored by Lior Amsalem's avatar Lior Amsalem Committed by Vinod Koul
Browse files

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: default avatarLior Amsalem <alior@marvell.com>
Signed-off-by: default avatarEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: default avatarVinod Koul <vinod.koul@intel.com>
parent 37380b98

drivers/dma/mv_xor.c

+34 −0
Original line number Diff line number Diff line
@@ -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)) {

drivers/dma/mv_xor.h

+6 −5
Original line number Diff line number Diff line
@@ -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